WorldWideScience

Sample records for range material temperature

  1. Characterization of advanced piezoelectric materials in the wide temperature range

    Energy Technology Data Exchange (ETDEWEB)

    Burianova, L.; Kopal, A.; Nosek, J

    2003-05-25

    We report about methods and results of our measurements of piezoelectric, dielectric and elastic properties of piezoelectric materials like crystals, ceramics, composites, polymers and thin layer composites. Among the methods, used in our laboratories are: the resonance method working in the temperature range 208-358 K, hydrostatic methods, both static and dynamic in the range 273-333 K, laser interferometric methods, using single and double-beam interferometer, working at room temperature, single and double-beam micro-interferometers, working inside of optical cryostat in the range 150-330 K, and pulse echo method for measurements of elastic coefficients, using ultrasonic set, working at room temperature. In our earlier papers we reported about some of our results of piezoelectric measurements of PZT ceramics using resonance method and laser interferometric method. The results of both methods were in good agreement. Now, the measurements are realized on 0-3 ceramic-polymer composites and thin layer composites. It is well known, that both intrinsic (material) and extrinsic (domain structure) contributions to properties of ferroelectric samples have characteristic, sometimes rather strong, temperature dependence. Therefore, any extension of temperature range of the above mentioned methods is welcomed.

  2. 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 ...

  3. 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)

  4. 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.

  5. Sample environment for neutron scattering measurements of internal stresses in engineering materials in the temperature range of 6 K to 300 K.

    Science.gov (United States)

    Kirichek, O; Timms, J D; Kelleher, J F; Down, R B E; Offer, C D; Kabra, S; Zhang, S Y

    2017-02-01

    Internal stresses in materials have a considerable effect on material properties including strength, fracture toughness, and fatigue resistance. The ENGIN-X beamline is an engineering science facility at ISIS optimized for the measurement of strain and stress using the atomic lattice planes as a strain gauge. Nowadays, the rapidly rising interest in the mechanical properties of engineering materials at low temperatures has been stimulated by the dynamic development of the cryogenic industry and the advanced applications of the superconductor technology. Here we present the design and discuss the test results of a new cryogenic sample environment system for neutron scattering measurements of internal stresses in engineering materials under a load of up to 100 kN and in the temperature range of 6 K to 300 K. Complete cooling of the system starting from the room temperature down to the base temperature takes around 90 min. Understanding of internal stresses in engineering materials at cryogenic temperatures is vital for the modelling and designing of cutting-edge superconducting magnets and other superconductor based applications.

  6. 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

    International Nuclear Information System (INIS)

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

    2011-01-01

    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.

  7. 1981 Annual status report. High-temperature materials

    International Nuclear Information System (INIS)

    1981-01-01

    The high temperature materials programme is executed at the JRC, Petten Establishment and has for the 1980/83 programme period the objective to promote within the European Community the development of high temperature materials required for future energy technologies. A range of engineering studies is being carried out. A data bank storing factual data on alloys for high temperature applications is being developed and has reached the operational phase

  8. 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 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...

  9. A wide temperature range irradiation cryostat for reasearch on solid state targets

    Energy Technology Data Exchange (ETDEWEB)

    Reeve, Scott; Dutz, Hartmut; Goertz, Stefan; Runkel, Stefan; Voge, Thomas [Physikalisches Institut, Universitaet Bonn (Germany)

    2012-07-01

    To qualitatively improve the data obtained in asymmetry measurements of scattering experiments the figure of merit (FOM) plays a major role and can reduce the data acquisition time when a certain precision in the measurement is needed. One of the defining factors for the improvement of the polarised experiment lies in the target choice and preparation, in particular the method employed to introduce the paramagnetic defects for the use of dynamic nuclear polarisation (DNP). To this end the Polarized Target Group in Bonn has developed a wide range temperature cryostat for the irradiation of potential target materials in which materials can be irradiated to varying doses at specified temperatures. The stable irradiation temperature of the materials can be controlled to within {+-}1 K over a range of 90 K

  10. Application of piezoceramic materials in low temperature scanning tunnel microscope

    International Nuclear Information System (INIS)

    Volodin, A.P.; Panich, A.E.

    1989-01-01

    Temperature dependences of the voltage-to-movement conversion coefficients for piezoceramic domestic materials PKR and TsTS-19 are measured using a capacitance dilatometer in the 0.4< T<300K temperature range. Anisotropy of thermal expansion of materials determined by the polarization vector is observed. Some recommendations concerning the use of the given materials in low-temperature scanning tunnel microscopes are given

  11. Minimizing material damage using low temperature irradiation

    Science.gov (United States)

    Craven, E.; Hasanain, F.; Winters, M.

    2012-08-01

    Scientific advancements in healthcare driven both by technological breakthroughs and an aging and increasingly obese population have lead to a changing medical device market. Complex products and devices are being developed to meet the demands of leading edge medical procedures. Specialized materials in these medical devices, including pharmaceuticals and biologics as well as exotic polymers present a challenge for radiation sterilization as many of these components cannot withstand conventional irradiation methods. The irradiation of materials at dry ice temperatures has emerged as a technique that can be used to decrease the radiation sensitivity of materials. The purpose of this study is to examine the effect of low temperature irradiation on a variety of polymer materials, and over a range of temperatures from 0 °C down to -80 °C. The effectiveness of microbial kill is also investigated under each of these conditions. The results of the study show that the effect of low temperature irradiation is material dependent and can alter the balance between crosslinking and chain scission of the polymer. Low temperatures also increase the dose required to achieve an equivalent microbiological kill, therefore dose setting exercises must be performed under the environmental conditions of use.

  12. Minimizing material damage using low temperature irradiation

    International Nuclear Information System (INIS)

    Craven, E.; Hasanain, F.; Winters, M.

    2012-01-01

    Scientific advancements in healthcare driven both by technological breakthroughs and an aging and increasingly obese population have lead to a changing medical device market. Complex products and devices are being developed to meet the demands of leading edge medical procedures. Specialized materials in these medical devices, including pharmaceuticals and biologics as well as exotic polymers present a challenge for radiation sterilization as many of these components cannot withstand conventional irradiation methods. The irradiation of materials at dry ice temperatures has emerged as a technique that can be used to decrease the radiation sensitivity of materials. The purpose of this study is to examine the effect of low temperature irradiation on a variety of polymer materials, and over a range of temperatures from 0 °C down to −80 °C. The effectiveness of microbial kill is also investigated under each of these conditions. The results of the study show that the effect of low temperature irradiation is material dependent and can alter the balance between crosslinking and chain scission of the polymer. Low temperatures also increase the dose required to achieve an equivalent microbiological kill, therefore dose setting exercises must be performed under the environmental conditions of use. - Highlights: ► A study is performed to quantify low temperature irradiation effects on polymer materials and BIs. ► Low temperature irradiation alters the balance of cross-linking and chain scissoning in polymers. ► Low temperatures provide radioprotection for BIs. ► Benefits of low temperatures are application specific and must be considered when dose setting.

  13. High temperature humidity sensing materials

    International Nuclear Information System (INIS)

    Tsai, P.P.; Tanase, S.; Greenblatt, M.

    1989-01-01

    This paper reports on new proton conducting materials prepared and characterized for potential applications in humidity sensing at temperatures higher than 100 degrees C by complex impedance or galvanic cell type techniques. Calcium metaphosphate, β-Ca(PO 3 ) 2 as a galvanic cell type sensor material yields reproducible signals in the range from 5 to 200 mm Hg water vapor pressure at 578 degrees C, with short response time (∼ 30 sec). Polycrystalline samples of α-Zr(HPO 4 ) 2 and KMo 3 P 5.8 Si 2 O 25 , and the gel converted ceramic, 0.10Li 2 O-0.25P 2 O 5 -0.65SiO 2 as impedance sensor materials show decreases in impedance with increasing humidity in the range from 9 mm Hg to 1 atm water vapor pressure at 179 degrees C

  14. Fluoride salts and container materials for thermal energy storage applications in the temperature range 973 - 1400 K

    Science.gov (United States)

    Misra, Ajay K.; Whittenberger, J. Daniel

    1987-01-01

    Multicomponent fluoride salt mixtures were characterized for use as latent heat of fusion heat storage materials in advanced solar dynamic space power systems with operating temperatures in the range of 973 to 1400 K. The melting points and eutectic composition for many systems with published phase diagrams were verified, and several new eutectic compositions were identified. Additionally, the heats of fusion of several binary and ternary eutectics and congruently melting intermediate compounds were measured by differential scanning calorimetry. The extent of corrosion of various metals by fluoride melts was estimated from thermodynamic considerations, and equilibrium conditions inside a containment vessel were calculated as functions of the initial moisture content of the salt and free volume above the molten salt. Preliminary experimental data on the corrosion of commercial, high-temperature alloys in LiF-19.5CaF2 and NaF-27CaF2-36MgF2 melts are presented and compared to the thermodynamic predictions.

  15. Transducer-based fiber Bragg grating high-temperature sensor with enhanced range and stability

    Science.gov (United States)

    Mamidi, Venkata Reddy; Kamineni, Srimannarayana; Ravinuthala, Lakshmi Narayana Sai Prasad; Tumu, Venkatappa Rao

    2017-09-01

    Fiber Bragg grating (FBG)-based high-temperature sensor with enhanced-temperature range and stability has been developed and tested. The sensor consists of an FBG and a mechanical transducer, which furnishes a linear temperature-dependent tensile strain on FBG by means of differential linear thermal expansion of two different ceramic materials. The designed sensor is tested over a range: 20°C to 1160°C and is expected to measure up to 1500°C.

  16. Mechanical degradation temperature of waste storage materials

    International Nuclear Information System (INIS)

    Fink, M.C.; Meyer, M.L.

    1993-01-01

    Heat loading analysis of the Solid Waste Disposal Facility (SWDF) waste storage configurations show the containers may exceed 90 degrees C without any radioactive decay heat contribution. Contamination containment is primarily controlled in TRU waste packaging by using multiple bag layers of polyvinyl chloride and polyethylene. Since literature values indicate that these thermoplastic materials can begin mechanical degradation at 66 degrees C, there was concern that the containment layers could be breached by heating. To better define the mechanical degradation temperature limits for the materials, a series of heating tests were conducted over a fifteen and thirty minute time interval. Samples of a low-density polyethylene (LDPE) bag, a high-density polyethylene (HDPE) high efficiency particulate air filter (HEPA) container, PVC bag and sealing tape were heated in a convection oven to temperatures ranging from 90 to 185 degrees C. The following temperature limits are recommended for each of the tested materials: (1) low-density polyethylene -- 110 degrees C; (2) polyvinyl chloride -- 130 degrees C; (3) high-density polyethylene -- 140 degrees C; (4) sealing tape -- 140 degrees C. Testing with LDPE and PVC at temperatures ranging from 110 to 130 degrees C for 60 and 120 minutes also showed no observable differences between the samples exposed at 15 and 30 minute intervals. Although these observed temperature limits differ from the literature values, the trend of HDPE having a higher temperature than LDPE is consistent with the reference literature. Experimental observations indicate that the HDPE softens at elevated temperatures, but will retain its shape upon cooling. In SWDF storage practices, this might indicate some distortion of the waste container, but catastrophic failure of the liner due to elevated temperatures (<185 degrees C) is not anticipated

  17. Fluoride salts as phase change materials for thermal energy storage in the temperature range 1000-1400 K

    Science.gov (United States)

    Misra, Ajay K.

    1988-01-01

    Eutectic compositions and congruently melting intermediate compounds in binary and ternary fluoride salt systems were characterized for potential use as latent heat of fusion phase change materials to store thermal energy in the temperature range 1000-1400 K. The melting points and eutectic compositions for many systems with published phase diagrams were experimentally verified and new eutectic compositions having melting points between 1000 and 1400 K were identified. Heats of fusion of several binary and ternary eutectics and congruently melting compounds were experimentally measured by differential scanning calorimetry. For a few systems in which heats of mixing in the melts have been measured, heats of fusion of the eutectics were calculated from thermodynamic considerations and good agreement was obtained between the measured and calculated values. Several combinations of salts with high heats of fusion per unit mass (greater than 0.7 kJ/g) have been identified for possible use as phase change materials in advanced solar dynamic space power applications.

  18. High temperature creep behavior in the (α + β) phase temperature range of M5 alloy

    International Nuclear Information System (INIS)

    Trego, G.

    2011-01-01

    The isothermal steady-state creep behavior of a M5 thin sheet alloy in a vacuum environment was investigated in the (α + β) temperature, low-stress (1-10 MPa) range. To this aim, the simplest approach consists in identifying α and β creep flow rules in their respective single-phase temperature ranges and extrapolating them in the two-phase domain. However, the (α + β) experimental behavior may fall outside any bounds calculated using such creep flow data. Here, the model was improved for each phase by considering two microstructural effects: (i) Grain size: Thermo-mechanical treatments applied on the material yielded various controlled grain size distributions. Creep tests in near-α and near-β ranges evidenced a strong grain-size effect, especially in the diffusional creep regime. (ii) Chemical contrast between the two phases in the (α + β) range: From thermodynamic calculations and microstructural investigations, the β phase is enriched in Nb and depleted in O (the reverse being true for the α phase). Thus, creep tests were performed on model Zr-Nb-O thin sheets with Nb and O concentrations representative of each phase in the considered temperature range. New α and β creep flow equations were developed from this extended experimental database and used to compute, via a finite element model, the creep rates of the two-phase material. The 3D morphology of phases (β grains nucleated at α grain boundaries) was explicitly introduced in the computations. The effect of phase morphology on the macroscopic creep flow was shown using this specific morphology, compared to other typical morphologies and to experimental data. (author) [fr

  19. Long-term creep behavior of high-temperature gas turbine materials under constant and variable stress

    International Nuclear Information System (INIS)

    Granacher, J.; Preussler, T.

    1987-01-01

    Within the framework of the documented research project, extensive creep rupture tests were carried out with characteristic, high-temperature gas turbine materials for establishment of improved design data. In the range of the main application temperatures and in stress ranges down to application-relevant values the tests extended over a period of about 40,000 hours. In addition, long-term annealing tests were carried out in the most important temperature ranges for the measurement of the density-dependent straim, which almost always manifested itself as a material contraction. Furthermore, hot tensile tests were carried out for the description of the elastoplastic short-term behavior. Several creep curves were derived from the results of the different tests with a differentiated evaluation method. On the basis of these creep curves, creep equations were set up for a series of materials which are valid in the entire examined temperature range and stress range and up to the end of the secondary creep range. Also, equations for the time-temperature-dependent description of the material contraction behavior were derived. With these equations, the high-temperature deformation behavior of the examined materials under constant creep stress can be described simply and application-oriented. (orig.) With 109 figs., 19 tabs., 77 refs [de

  20. A comparison between rare earth and transition metals working as magnetic materials in an AMR refrigerator in the room temperature range

    International Nuclear Information System (INIS)

    Aprea, C.; Greco, A.; Maiorino, A.; Masselli, C.

    2015-01-01

    This paper describes a two-dimensional (2D) multiphysics model of a packed bed regenerator made of magnetocaloric material. The regenerator operates as a refrigerant for a magnetic refrigerator operating at room temperature on the strength of an active magnetic regenerator (AMR) cycle. The model is able to simulate the thermofluidodynamic behavior of the magnetocaloric material and the magnetocaloric effect of the refrigerant. The model has been validated by means of experimental results. Different magnetic materials have been tested with the model as refrigerants: pure gadolinium, second order phase magnetic transition Pr_0_._4_5Sr_0_._3_5MnO_3 and first order phase magnetic transition alloys Gd_5(Si_xGe_1_−_x)_4, LaFe_1_1_._3_8_4Mn_0_._3_5_6Si_1_._2_6H_1_._5_2, LaFe_1_1_._0_5Co_0_._9_4Si_1_._1_0 and MnFeP_0_._4_5As_0_._5_5. The tests were performed with fixed fluid flow rate (5 l/min), AMR cycle frequency (1.25 Hz) and cold heat exchanger temperature (288 K) while the hot heat exchanger temperature was varied in the range 295–302 K. The results, generated for a magnetic induction which varies from 0 to 1.5 T, are presented in terms of temperature span, refrigeration power and coefficient of performance. From a global point of view (performances and cost), the most promising materials are LaFeSi compounds which are really cheaper than rare earth compounds and they give a performance sufficiently higher than gadolinium. - Graphical abstract: • Active Magnetic Refrigeration (AMR) cycle; • First Order Transition magnetic materials (FOMT); • Second Order Transition magnetic materials (SOMT). - Highlights: • Comparison between different magnetic materials. • 2D model of an Active Magnetic Regenerative refrigeration cycle. • Validation of the model with experimental data. • Gd_5(Si_xGe_1_−_x)_4 is the most performant magnetic material. • The most promising are LaFeSi compounds which are cheaper and they give high performances.

  1. High temperature materials

    International Nuclear Information System (INIS)

    2003-01-01

    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.)

  2. Fluoride salts and container materials for thermal energy storage applications in the temperature range 973 to 1400 K

    Science.gov (United States)

    Misra, Ajay K.; Whittenberger, J. Daniel

    1987-01-01

    Multicomponent fluoride salt mixtures were characterized for use as latent heat of fusion heat storage materials in advanced solar dynamic space power systems with operating temperatures in the range of 973 to 1400 K. The melting points and eutectic composition for many systems with published phase diagrams were verified, and several new eutectic compositions were identified. Additionally, the heats of fusion of several binary and ternary eutectics and congruently melting intermediate compounds were measured by differential scanning calorimetry. The extent of corrosion of various metals by fluoride melts was estimated from thermodynamic considerations, and equilibrium conditions inside a containment vessel were calculated as functions of the initial moisture content of the salt and free volume above the molten salt. Preliminary experimental data on the corrosion of commercial, high-temperature alloys in LiF-19.5CaF2 and NaF-27CaF2-36MgF2 melts are presented and compared to the thermodynamic predictions.

  3. Variability of Diurnal Temperature Range During Winter Over Western Himalaya: Range- and Altitude-Wise Study

    Science.gov (United States)

    Shekhar, M. S.; Devi, Usha; Dash, S. K.; Singh, G. P.; Singh, Amreek

    2018-04-01

    The current trends in diurnal temperature range, maximum temperature, minimum temperature, mean temperature, and sun shine hours over different ranges and altitudes of Western Himalaya during winter have been studied. Analysis of 25 years of data shows an increasing trend in diurnal temperature range over all the ranges and altitudes of Western Himalaya during winter, thereby confirming regional warming of the region due to present climate change and global warming. Statistical studies show significant increasing trend in maximum temperature over all the ranges and altitudes of Western Himalaya. Minimum temperature shows significant decreasing trend over Pir Panjal and Shamshawari range and significant increasing trend over higher altitude of Western Himalaya. Similarly, sunshine hours show significant decreasing trend over Karakoram range. There exists strong positive correlation between diurnal temperature range and maximum temperature for all the ranges and altitudes of Western Himalaya. Strong negative correlation exists between diurnal temperature range and minimum temperature over Shamshawari and Great Himalaya range and lower altitude of Western Himalaya. Sunshine hours show strong positive correlation with diurnal temperature range over Pir Panjal and Great Himalaya range and lower and higher altitudes.

  4. Methods for measuring the spectral reflectivity of advanced materials at high temperature

    International Nuclear Information System (INIS)

    Salikhov, T.P.; Kan, V.V.

    1993-01-01

    For investigation in the domain of advanced materials as well as for new technologies there is an urgent need for knowledge of the spectral reflectivity of the materials specially at high temperatures. However the methods available are mostly intended for measuring the model materials with specular or diffuse reflection surface. This is not quite correct since advanced materials have mixed specular diffuse reflection surfaces. New methods for reflectivity measurements of materials in the visible, near and middle infrared range at high temperature, regardless of surface texture, have been developed. The advantages of the methods proposed are as flows: (a) the facility of performing the reflectivity measurements for materials with mixed specular diffuse reflectance; (b) wide spectral range 0,38-8 micro m; (c) wide temperature range 300-3000 K; (d) high accuracy and rapid measurements. The methods are based on the following principals (i) Diffuse irradiation of the sample surface and the use of Helkholtz reciprocity principle to determine the directional hemispherical reflectivity ii) Pulse polychromatic probing of the sample by additional light source. The first principle excludes the influence of the angular reflection distribution of sample surface on data obtained. The second principle gives the possibility of simultaneous measurements of the reflectivity. The second principle gives the possibility of simultaneous measurements of the reflectivity in wide spectral range. On the basis of these principles for high temperature reflectometers have been developed and discussed here. (author)

  5. Study of tertiary creep instability in several elevated-temperature structural materials

    International Nuclear Information System (INIS)

    Booker, M.K.; Sikka, V.K.

    1978-01-01

    Data for a number of common elevated temperature structural materials have been analyzed to yield mathematical predictions for the time and strain to tertiary creep at various rupture lives and temperatures. Materials examined include types 304 and 316 stainless steel, 2 1/4 Cr-1 Mo steel, alloy 800H, alloy 718, Hastelloy alloy X, and ERNiCr--3 weld metal. Data were typically examined over a range of creep temperatures for rupture lives ranging from less than 100 to greater than 10,000 hours. Within a given material, trends in these quantities can be consistently described, but it is difficult to directly relate the onset of tertiary creep to failure-inducing instabilities. A series of discontinued tests for alloy 718 at 649 and 620 0 C showed that the material fails by intergranular cracking but that no significant intergranular cracking occurs until well after the onset of tertiary creep

  6. Modelling flow and work hardening behaviour of cold worked Zr–2.5Nb pressure tube material in the temperature range of 30–600 oC

    International Nuclear Information System (INIS)

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

    2014-01-01

    Under a postulated accident scenario of loss of cooling medium in an Indian Pressurised Heavy Water Reactor (IPHWR), temperature of the pressure tubes can rise and lead to large deformations. In order to investigate the modes of deformation of pressure tube – calandria tube assembly, material property data defining the flow behaviour over a temperature range from room temperature (RT) to 800 o C are needed. It is of practical importance to formulate mathematical equations to describe the stress–strain relationships of a material for a variety of reasons, such as the analysis of forming operations and the assessment of component's performance in service. A number of constitutive relations of empirical nature have been proposed and they have been found very suitable to describe the behaviour of a material. Although these relations are of empirical nature, various metallurgical factors appear to decide applicability of each of these relations. For example, grain size influences mainly the friction stress while the strain hardening is governed by dislocation density. In a recent work, tensile deformation behaviour of pressure tube material of IPHWR has been carried out over a range of temperature and strain rates (Dureja et al., 2011). It has been found that the strength parameters (yield and ultimate tensile strength) vary along the length of the tube with higher strength at the trailing end as compared to the leading end. This stems from cooling of the billet during the extrusion process which results in the variation of microstructure, texture and dislocation density from the leading to the trailing end. In addition, the variation in metallurgical parameters is also expected to influence the work hardening behaviour, which is known to control the plastic instability (related to uniform strain). In the present investigation, the tensile flow and work-hardening behaviour of a cold worked Zr–2.5Nb pressure tube material of IPHWRs has been studied over the

  7. Phase Change Material Selection for Thermal Energy Storage at High Temperature Range between 210 °C and 270 °C

    Directory of Open Access Journals (Sweden)

    José Miguel Maldonado

    2018-04-01

    Full Text Available The improvement of thermal energy storage systems implemented in solar technologies increases not only their performance but also their dispatchability and competitiveness in the energy market. Latent heat thermal energy storage systems are one of those storing methods. Therefore, the need of finding the best materials for each application becomes an appealing research subject. The main goal of this paper is to find suitable and economically viable materials able to work as phase change material (PCM within the temperature range of 210–270 °C and endure daily loading and unloading processes in a system with Fresnel collector and an organic Rankine cycle (ORC. Twenty-six materials have been tested and characterized in terms of their thermophysical conditions, thermal and cycling stability, and health hazard. Two materials out of the 26 candidates achieved the last stage of the selection process. However, one of the two finalists would require an inert working atmosphere, which would highly increase the cost for the real scale application. This leads to a unique suitable material, solar salt (40 wt % KNO3/60 wt % NaNO3.

  8. Thermal-mechanical fatigue of high temperature structural materials

    Science.gov (United States)

    Renauld, Mark Leo

    Experimental and analytical methods were developed to address the effect of thermal-mechanical strain cycling on high temperature structural materials under uniaxial and biaxial stress states. Two materials were used in the investigation, a nickel-base superalloy of low ductility, IN-738LC and a high ductility material, 316 stainless steel. A uniaxial life prediction model for the IN-738LC material was based on tensile hysteresis energy measured in stabilized, mid-life hysteresis loops. Hold-time effects and temperature cycling were incorporated in the hysteresis energy approach. Crack growth analysis was also included in the model to predict the number of TMF cycles to initiate and grow a fatigue crack through the coating. The nickel-base superalloy, IN-738LC, was primarily tested in out-of-phase (OP) TMF with a temperature range from 482-871sp°C (900-1600sp°F) under continuous and compressive hold-time cycling. IN-738LC fatigue specimens were coated either with an aluminide, NiCoCrAlHfSi overlay or CoNiCrAlY overlay coating on the outer surface of the specimen. Metallurgical failure analysis via optical and scanning electron microscopy, was used to characterize failure behavior of both substrate and coating materials. Type 316 SS was subjected to continuous biaxial strain cycling with an in-phase (IP) TMF loading and a temperature range from 399-621sp°C (750-1150sp°F). As a result, a biaxial TMF life prediction model was proposed on the basis of an extended isothermal fatigue model. The model incorporates a frequency effect and phase factors to assess the different damage mechanisms observed during TMF loading. The model was also applied to biaxial TMF data generated on uncoated IN-738LC.

  9. Effect of thermal cycling on the transformation temperature ranges of a Ni-Ti shape memory alloy

    International Nuclear Information System (INIS)

    Paula, A.S.; Canejo, J.P.H.G.; Martins, R.M.S.; Braz Fernandes, F.M.

    2003-01-01

    Shape memory alloys (SMA) represents a class of metallic materials that has the capability of recovering a previously defined initial shape when subject to an adequate thermomechanical treatment. The present work aims to study the influence of thermal cycles on the transition temperatures of a Ni-Ti alloy. In this system, small variations around the equiatomic composition give rise to significant transformation temperature variations ranging from 173 to 373 K. SMA usually presents the shape memory effect after an annealing treatment at ca. 973 K. The optimisation of the thermomechanical treatment will allow to 'tune' the material to different transformation temperature ranges from the same starting material, just by changing the processing conditions. Differential scanning calorimeter (DSC) and in situ high-temperature X-ray diffraction (XRD) have been used to identify the transformation temperatures and the phases that are present after different thermal cycles. The results concerning a series of thermal cycles with different heating and cooling rates (from 1.67x10 -2 to 1.25x10 -1 K/s) and different holding temperatures (from 473 to 1033 K) are presented

  10. Evaluation of creep-fatigue strength of P122 high temperature boiler material

    International Nuclear Information System (INIS)

    Pumwa, John

    2003-01-01

    In components, which operate at high temperatures, changes in conditions at the beginning and end of operation or during operation result in transient temperature gradients. If these transients are repeated, the differential thermal expansion during each transient may result in thermally induced cyclic stresses. The extent of the resulting fatigue damage depends on the nature and frequency of the transient, the thermal gradient in the component, and the material properties. Components, which are subjected to thermally induced stresses generally, operate within the creep range so that damage due to both fatigue and creep has to be taken into account. In order to select the correct materials for these hostile operating environmental conditions, it is vitally important to understand the behaviour of mechanical properties such as creep-fatigue properties of these materials. This paper reports the results of standard creep-fatigue tests conducted using P122 (HCM12A or 12Cr-1.8W-1.5Cu) high temperature boiler material. P122 is one of the latest developed materials for high temperature environments, which has the potential to be successful in such hostile operation environments. The tests were conducted at temperatures ranging from 550degC to 700degC at 50degC intervals with strain ranges of ±1.5 to ±3.0% at 0.5% intervals and a strain rate of 4 x 10 -3 s -1 with an application of 10-minute tensile hold time using a closed-loop hydraulic Instron material testing machine with a servo hydraulic controller. The results confirm that P122 is comparable to conventional high temperature steels. (author)

  11. 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.)

  12. High-temperature materials and structural ceramics

    International Nuclear Information System (INIS)

    1990-01-01

    This report gives a survey of research work in the area of high-temperature materials and structural ceramics of the KFA (Juelich Nuclear Research Center). The following topics are treated: (1) For energy facilities: ODS materials for gas turbine blades and heat exchangers; assessment of the remaining life of main steam pipes, material characterization and material stress limits for First-Wall components; metallic and graphitic materials for high-temperature reactors. (2) For process engineering plants: composites for reformer tubes and cracking tubes; ceramic/ceramic joints and metal/ceramic and metal/metal joints; Composites and alloys for rolling bearing and sliding systems up to application temperatures of 1000deg C; high-temperature corrosion of metal and ceramic material; porous ceramic high-temperature filters and moulding coat-mix techniques; electrically conducting ceramic material (superconductors, fuel cells, solid electrolytes); high-temperature light sources (high-temperature chemistry); oil vapor engines with caramic components; ODS materials for components in diesel engines and vehicle gas turbines. (MM) [de

  13. Radiation tests at cryogenic temperature on selected organic materials for LHC

    International Nuclear Information System (INIS)

    Humer, K.; Weber, H.W.; Szeless, B.; Tavlet, M.

    1997-01-01

    Future multi-TeV particle accelerators like the CERN Large Hadron Collider (LHC) will use superconducting magnets in which organic materials will be exposed to high radiation levels at temperatures as low as 2 K. A representative selection of organic materials comprising insulating films, cable insulations, epoxy resins and composites were exposed to neutron and gamma radiation of a nuclear reactor. Depending on the type of materials, the integrated radiation doses varied between 180 kGy and 155 MGy. During irradiation, the samples were kept close to the boiling temperature of liquid nitrogen, i.e. at 80 K, and thereafter stored in liquid nitrogen and transferred at the same temperature into the testing device for measurement of tensile and flexural strength. Tests were carried out on the same materials at similar dose rates at room temperature, and the results are compared with the ones obtained at cryogenic temperature. They show that within the selected dose range, a number of organic materials are suitable for use in radiation fields of the LHC at cryogenic temperature

  14. High Temperature Materials Characterization and Advanced Materials Development

    International Nuclear Information System (INIS)

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

    2007-06-01

    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

  15. MICROWAVE MEASUREMENT OF REFRACTORY MATERIALS AT HIGH-TEMPERATURE

    International Nuclear Information System (INIS)

    Kharkovsky, S.; Zoughi, R.; Smith, J.; Davis, B.; Limmer, R.

    2009-01-01

    Knowledge of the electrical behavior of refractory materials may enable the development and optimization of microwave nondestructive techniques to detect and evaluate changes in their physical properties while the materials are in service. This paper presents the results of a limited and preliminary investigation in which two refractory materials (dense chrome and dense zircon) were subjected to increasing temperature in a furnace and in which a frequency-modulated continuous-wave radar operating in the frequency range of 8-18 GHz radar was used to evaluate their attenuation properties.

  16. Microwave Measurement of Refractory Materials at High-Temperature

    Science.gov (United States)

    Kharkovsky, S.; Zoughi, R.; Smith, J.; Davis, B.; Limmer, R.

    2009-03-01

    Knowledge of the electrical behavior of refractory materials may enable the development and optimization of microwave nondestructive techniques to detect and evaluate changes in their physical properties while the materials are in service. This paper presents the results of a limited and preliminary investigation in which two refractory materials (dense chrome and dense zircon) were subjected to increasing temperature in a furnace and in which a frequency-modulated continuous-wave radar operating in the frequency range of 8-18 GHz radar was used to evaluate their attenuation properties.

  17. Pseudo-icosahedral Cr55Al232 -δ as a high-temperature protective material

    Science.gov (United States)

    Rosa, R.; Bhattacharya, S.; Pabla, J.; He, H.; Misuraca, J.; Nakajima, Y.; Bender, A. D.; Antonacci, A. K.; Adrip, W.; McNally, D. E.; Zebro, A.; Kamenov, P.; Geschwind, G.; Ghose, S.; Dooryhee, E.; Ibrahim, A.; Tritt, T. M.; Aronson, M. C.; Simonson, J. W.

    2018-03-01

    We report here a course of basic research into the potential suitability of a pseudo-icosahedral Cr aluminide as a material for high-temperature protective coatings. Cr55Al232 -δ [ δ =2.70 (6 ) ] exhibits high hardness at room temperature as well as low thermal conductivity and excellent oxidation resistance at 973 K, with an oxidation rate comparable to those of softer, denser benchmark materials. The origin of these promising properties can be traced to competing long-range and short-range symmetries within the pseudo-icosahedral crystal structure, suggesting new criteria for future materials research.

  18. Short-time, high temperature mechanical testing of electrically conductive materials

    International Nuclear Information System (INIS)

    Marion, R.H.; Karnes, C.H.

    1975-10-01

    Design and performance details are given for a facility which was developed to obtain the mechanical properties of materials under high heating rate or transient temperature conditions and medium strain rates. The system is shown to be applicable to materials possessing electrical resistivities ranging from that of aluminum to that of graphite without taxing the heating capability. Heating rates as high as 2000 0 K/s in graphite are attained under controlled conditions. Methods of measuring temperature and the effects of expected temperature distributions are discussed. A method for measuring strain valid for transient temperature conditions to 3000 0 K is described. Results are presented for the stress-strain behavior of 316 stainless steel and ATJ(S) graphite obtained for heating times of a few seconds. (auth)

  19. Thermal conductivity of an organic phase change material/expanded graphite composite across the phase change temperature range and a novel thermal conductivity model

    International Nuclear Information System (INIS)

    Ling, Ziye; Chen, Jiajie; Xu, Tao; Fang, Xiaoming; Gao, Xuenong; Zhang, Zhengguo

    2015-01-01

    Highlights: • Expanded graphite can improve thermal conductivity of RT44HC by 20–60 times. • Thermal conductivity of PCM/EG composites keeps constant before/after melting. • Thermal conductivity of PCMs nearly doubled during phase changing. • Thermal conductivity of composite PCM increases with density and percentage of EG. • The simple model predicts thermal conductivity of EG-based composites accurately. - Abstract: This work studies factors that affect the thermal conductivity of an organic phase change material (PCM), RT44HC/expanded graphite (EG) composite, which include: EG mass fraction, composite PCM density and temperature. The increase of EG mass fraction and bulk density will both enhance thermal conductivity of composite PCMs, by up to 60 times. Thermal conductivity of RT44HC/EG composites remains independent on temperature outside the phase change range (40–45 °C), but nearly doubles during the phase change. The narrow temperature change during the phase change allows the maximum heat flux or minimum temperature for heat source if attaching PCMs to a first (constant temperature) or second (constant heat flux) thermal boundary. At last, a simple thermal conductivity model for EG-based composites is put forward, based on only two parameters: mass fraction of EG and bulk density of the composite. This model is validated with experiment data presented in this paper and in literature, showing this model has general applicability to any composite of EG and poor thermal conductive materials

  20. High temperature material characterization and advanced materials development

    International Nuclear Information System (INIS)

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

    2005-03-01

    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

  1. Effects of temperature on mechanical properties of SU-8 photoresist material

    Energy Technology Data Exchange (ETDEWEB)

    Chung, Soon Wan; Park, Seung Bae [State University of New York, New York (United States)

    2013-09-15

    A representative fabrication processing of SU-8 photoresist, Ultraviolet (UV) lithography is usually composed of spin coat, soft bake, UV exposure, post exposure bake (PEB), development and optional hard bake, etc. The exposed region of SU-8 is crosslinked during the PEB process and its physical properties highly depend on UV exposure and PEB condition. This work was initiated to investigate if thermal baking after fabrication can affect the mechanical properties of SU-8 photoresist material because SU-8 is trying to be used as a structural material for MEMS operated at high temperature. Since a temperature of 95 .deg. C is normally recommended for PEB process, elevated temperatures up to 200 .deg. C were considered for the optional hard bake process. The viscoelastic material properties were measured by dynamic mechanical analyses (DMA). Also, pulling tests were performed to obtain Young's modulus and Poisson's ratio as a function of strain rate in a wide temperature range. From this study, the effects of temperature on the elastic and viscoelastic material properties of SU-8 were obtained.

  2. Effects of temperature on mechanical properties of SU-8 photoresist material

    International Nuclear Information System (INIS)

    Chung, Soon Wan; Park, Seung Bae

    2013-01-01

    A representative fabrication processing of SU-8 photoresist, Ultraviolet (UV) lithography is usually composed of spin coat, soft bake, UV exposure, post exposure bake (PEB), development and optional hard bake, etc. The exposed region of SU-8 is crosslinked during the PEB process and its physical properties highly depend on UV exposure and PEB condition. This work was initiated to investigate if thermal baking after fabrication can affect the mechanical properties of SU-8 photoresist material because SU-8 is trying to be used as a structural material for MEMS operated at high temperature. Since a temperature of 95 .deg. C is normally recommended for PEB process, elevated temperatures up to 200 .deg. C were considered for the optional hard bake process. The viscoelastic material properties were measured by dynamic mechanical analyses (DMA). Also, pulling tests were performed to obtain Young's modulus and Poisson's ratio as a function of strain rate in a wide temperature range. From this study, the effects of temperature on the elastic and viscoelastic material properties of SU-8 were obtained.

  3. The dynamical mechanical properties of tungsten under compression at working temperature range of divertors

    International Nuclear Information System (INIS)

    Zhu, C.C.; Song, Y.T.; Peng, X.B.; Wei, Y.P.; Mao, X.; Li, W.X.; Qian, X.Y.

    2016-01-01

    In the divertor structure of ITER and EAST with mono-block module, tungsten plays not only a role of armor material but also a role of structural material, because electromagnetic (EM) impact will be exerted on tungsten components in VDEs or CQ. The EM loads can reach to 100 MN, which would cause high strain rates. In addition, directly exposed to high-temperature plasma, the temperature regime of divertor components is complex. Aiming at studying dynamical response of tungsten divertors under EM loads, an experiment on tungsten employed in EAST divertors was performed using a Kolsky bar system. The testing strain rates and temperatures is derived from actual working conditions, which makes the constitutive equation concluded by using John-Cook model and testing data very accurate and practical. The work would give a guidance to estimate the dynamical response, fatigue life and damage evolution of tungsten divertor components under EM impact loads. - Graphical abstract: From the comparison between the experimental curves and the predicted curves calculated by adopting the corrected m, it is very clear that the new model is of great capability to explain the deformation behavior of the tungsten material under dynamic compression at high temperatures. (EC, PC and PCM refers to experimental curve, predicted curve and predicted curve with a corrected m. Different colors represent different scenarios.). - Highlights: • Test research on dynamic properties of tungsten at working temperature range and strain rate range of divertors. • Constitutive equation descrbing strain hardening, strain rate hardening and temperature softening. • A guidance to estimate dynamical response and damage evolution of tungsten divertor components under impact.

  4. Modelling of monovacancy diffusion in W over wide temperature range

    International Nuclear Information System (INIS)

    Bukonte, L.; Ahlgren, T.; Heinola, K.

    2014-01-01

    The diffusion of monovacancies in tungsten is studied computationally over a wide temperature range from 1300 K until the melting point of the material. Our modelling is based on Molecular Dynamics technique and Density Functional Theory. The monovacancy migration barriers are calculated using nudged elastic band method for nearest and next-nearest neighbour monovacancy jumps. The diffusion pre-exponential factor for monovacancy diffusion is found to be two to three orders of magnitude higher than commonly used in computational studies, resulting in attempt frequency of the order 10 15 Hz. Multiple nearest neighbour jumps of monovacancy are found to play an important role in the contribution to the total diffusion coefficient, especially at temperatures above 2/3 of T m , resulting in an upward curvature of the Arrhenius diagram. The probabilities for different nearest neighbour jumps for monovacancy in W are calculated at different temperatures

  5. Nickel-titanium alloys: stress-related temperature transitional range.

    Science.gov (United States)

    Santoro, M; Beshers, D N

    2000-12-01

    The inducement of mechanical stress within nickel-titanium wires can influence the transitional temperature range of the alloy and therefore the expression of the superelastic properties. An analogous variation of the transitional temperature range may be expected during orthodontic therapy, when the archwires are engaged into the brackets. To investigate this possibility, samples of currently used orthodontic nickel-titanium wires (Sentalloy, GAC; Copper Ni-Ti superelastic at 27 degrees C, 35 degrees C, 40 degrees C, Ormco; Nitinol Heat-Activated, 3M-Unitek) were subjected to temperature cycles ranging between 4 degrees C and 60 degrees C. The wires were mounted in a plexiglass loading device designed to simulate clinical situations of minimum and severe dental crowding. Electrical resistivity was used to monitor the phase transformations. The data were analyzed with paired t tests. The results confirmed the presence of displacements of the transitional temperature ranges toward higher temperatures when stress was induced. Because nickel-titanium wires are most commonly used during the aligning stage in cases of severe dental crowding, particular attention was given to the performance of the orthodontic wires under maximum loading. An alloy with a stress-related transitional temperature range corresponding to the fluctuations of the oral temperature should express superelastic properties more consistently than others. According to our results, Copper Ni-Ti 27 degrees C and Nitinol Heat-Activated wires may be considered suitable alloys for the alignment stage.

  6. Thermal Stability of Austempered Ductile Iron Evaluated in a Temperature Range of 20-300K

    Directory of Open Access Journals (Sweden)

    Dawid MYSZKA

    2016-05-01

    Full Text Available The aim of this article was to determine through changes in magnetic properties the stability of the austempered ductile iron (ADI microstructure during temperature changes in a range of 20 – 300 K. The measurements were taken in a vibrating sample magnetometer (VSM using Fe27Ni2TiMoAlNb austenitic stainless steel and four types of austempered ductile iron obtained under various heat treatment conditions. The plotted curves showing changes in the magnetisation degree as a function of temperature had a number of characteristic points illustrating changes taking place in the microstructure. For each of the materials examined, the martensite start temperature Ms and the temperature range within which the martensitic transformation takes place were identified.

  7. Deformability of 12MKh steel within the temperature range of polymorphous transformations

    International Nuclear Information System (INIS)

    Surovtsev, A.P.; Sukhanov, V.E.

    1987-01-01

    Deformability and the structure of 12 MKh steel under tension, upsetting and torsion within the temperature range of polymorphous transformations have been investigated. Tests for tension showed the presence of two plasticity maxima, which correspond to the temperatures of P-A and F-A structural transformation beginning. Loss of strength during deformation is connected with dynamic polygonization and the initial stage of dynamic recrystallization as well as the state preceding ferrite transformation. Loss of plasticity is observed at the temperature accompanying the end of F-A transformation; it is explained by the formation of more strength martensite and by increase of material porosity as a result of the transformation with volume decrease

  8. Deformability of 12MKh steel within the temperature range of polymorphous transformations

    Energy Technology Data Exchange (ETDEWEB)

    Surovtsev, A P; Sukhanov, V E

    1987-01-01

    Deformability and the structure of 12 MKh steel under tension, upsetting and torsion within the temperature range of polymorphous transformations have been investigated. Tests for tension showed the presence of two plasticity maxima, which correspond to the temperatures of P-A and F-A structural transformation beginning. Loss of strength during deformation is connected with dynamic polygonization and the initial stage of dynamic recrystallization as well as the state preceding ferrite transformation. Loss of plasticity is observed at the temperature accompanying the end of F-A transformation; it is explained by the formation of more strength martensite and by increase of material porosity as a result of the transformation with volume decrease.

  9. Shock-induced synthesis of high temperature superconducting materials

    Science.gov (United States)

    Ginley, D.S.; Graham, R.A.; Morosin, B.; Venturini, E.L.

    1987-06-18

    It has now been determined that the unique features of the high pressure shock method, especially the shock-induced chemical synthesis technique, are fully applicable to high temperature superconducting materials. Extraordinarily high yields are achievable in accordance with this invention, e.g., generally in the range from about 20% to about 99%, often in the range from about 50% to about 90%, lower and higher yields, of course, also being possible. The method of this invention involves the application of a controlled high pressure shock compression pulse which can be produced in any conventional manner, e.g., by detonation of a high explosive material, the impact of a high speed projectile or the effect of intense pulsed radiation sources such as lasers or electron beams. Examples and a discussion are presented.

  10. PETIs as High-Temperature Resin-Transfer-Molding Materials

    Science.gov (United States)

    Connell, John N.; Smith, Joseph G., Jr.; Hergenrother, Paul M.

    2005-01-01

    Compositions of, and processes for fabricating, high-temperature composite materials from phenylethynyl-terminated imide (PETI) oligomers by resin-transfer molding (RTM) and resin infusion have been developed. Composites having a combination of excellent mechanical properties and long-term high-temperature stability have been readily fabricated. These materials are particularly useful for the fabrication of high-temperature structures for jet-engine components, structural components on highspeed aircraft, spacecraft, and missiles. Phenylethynyl-terminated amide acid oligomers that are precursors of PETI oligomers are easily made through the reaction of a mixture of aromatic diamines with aromatic dianhydrides at high stoichiometric offsets and 4-phenylethynylphthalic anhydride (PEPA) as an end-capper in a polar solvent such as N-methylpyrrolidinone (NMP). These oligomers are subsequently cyclodehydrated -- for example, by heating the solution in the presence of toluene to remove the water by azeotropic distillation to form low-molecular-weight imide oligomers. More precisely, what is obtained is a mixture of PETI oligomeric species, spanning a range of molecular weights, that exhibits a stable melt viscosity of less than approximately 60 poise (and generally less than 10 poise) at a temperature below 300 deg C. After curing of the oligomers at a temperature of 371 deg C, the resulting polymer can have a glass-transition temperature (Tg) as high as 375 C, the exact value depending on the compositions.

  11. Methodology of investigation of the effect of ultrasonic oscillations on mechanical properties of structural materials in a wide range of temperatures and strain rates

    International Nuclear Information System (INIS)

    Bakay, S.O.; Gurin, V.A.; Gurin, I.V.; Neklyudov, I.M.; Gorbatenko, V.M.; Netesov, V.M.; Dub, S.N.

    2007-01-01

    The present message is devoted to the description of a method of research of influence of ultrasound on physicomechanical properties of constructional materials during plastic deformation in vacuum. The functional diagram and the description of created experimental facility which allows to carry out researches by this method is resulted. The created method and the equipment it has been approved for studying influence of ultrasound on physicomechanical properties of carbon composite materials of nuclear industry. Mechanical properties of carbon - carbon composite materials are investigated in a range of temperatures from room up to 600 degree C, at various strain rates, in conditions of ultrasonic vibrations and without them. The analysis of results received is carried out at use of a method of mechanical tests of samples of carbon before ultrasonic processing on nanohardness. The comparative estimation of the received experimental data is resulted

  12. 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.

  13. Wide range scaling laws for radiation driven shock speed, wall albedo and ablation parameters for high-Z materials

    Science.gov (United States)

    Mishra, Gaurav; Ghosh, Karabi; Ray, Aditi; Gupta, N. K.

    2018-06-01

    Radiation hydrodynamic (RHD) simulations for four different potential high-Z hohlraum materials, namely Tungsten (W), Gold (Au), Lead (Pb), and Uranium (U) are performed in order to investigate their performance with respect to x-ray absorption, re-emission and ablation properties, when irradiated by constant temperature drives. A universal functional form is derived for estimating time dependent wall albedo for high-Z materials. Among the high-Z materials studied, it is observed that for a fixed simulation time the albedo is maximum for Au below 250 eV, whereas it is maximum for U above 250 eV. New scaling laws for shock speed vs drive temperature, applicable over a wide temperature range of 100 eV to 500 eV, are proposed based on the physics of x-ray driven stationary ablation. The resulting scaling relation for a reference material Aluminium (Al), shows good agreement with that of Kauffman's power law for temperatures ranging from 100 eV to 275 eV. New scaling relations are also obtained for temperature dependent mass ablation rate and ablation pressure, through RHD simulation. Finally, our study reveals that for temperatures above 250 eV, U serves as a better hohlraum material since it offers maximum re-emission for x-rays along with comparable mass ablation rate. Nevertheless, traditional choice, Au works well for temperatures below 250 eV. Besides inertial confinement fusion (ICF), the new scaling relations may find its application in view-factor codes, which generally ignore atomic physics calculations of opacities and emissivities, details of laser-plasma interaction and hydrodynamic motions.

  14. A combined stochastic analysis of mean daily temperature and diurnal temperature range

    Science.gov (United States)

    Sirangelo, B.; Caloiero, T.; Coscarelli, R.; Ferrari, E.

    2018-03-01

    In this paper, a stochastic model, previously proposed for the maximum daily temperature, has been improved for the combined analysis of mean daily temperature and diurnal temperature range. In particular, the procedure applied to each variable sequentially performs the deseasonalization, by means of truncated Fourier series expansions, and the normalization of the temperature data, with the use of proper transformation functions. Then, a joint stochastic analysis of both the climatic variables has been performed by means of a FARIMA model, taking into account the stochastic dependency between the variables, namely introducing a cross-correlation between the standardized noises. The model has been applied to five daily temperature series of southern Italy. After the application of a Monte Carlo simulation procedure, the return periods of the joint behavior of the mean daily temperature and the diurnal temperature range have been evaluated. Moreover, the annual maxima of the temperature excursions in consecutive days have been analyzed for the synthetic series. The results obtained showed different behaviors probably linked to the distance from the sea and to the latitude of the station.

  15. 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

  16. 1982 Annual status report: high-temperature materials

    International Nuclear Information System (INIS)

    Van de Voorde, M.

    1983-01-01

    The High Temperature Materials Programme is executed at the JRC, Petten Establishment and has for the 1980/83 programme period the objective to promote within the European Community the development of high temperature materials required for future energy technologies. Materials and engineering studies include: corrosion with or without load, mechanical properties under static or dynamic loads, surface protection creep of tubular components in corrosive environments and high temperature materials data bank

  17. A luminescent Lanthanide-free MOF nanohybrid for highly sensitive ratiometric temperature sensing in physiological range.

    Science.gov (United States)

    Zhou, You; Zhang, Denan; Zeng, Jin; Gan, Ning; Cuan, Jing

    2018-05-01

    Luminescent MOF materials with tunable emissions and energy/charge transfer processes have been extensively explored as ratiometric temperature sensors. However, most of the ratiometric MOF thermometers reported thus far are based on the MOFs containing photoactive lanthanides, which are potentially facing cost issue and serious supply shortage. Here, we present a ratiometric luminescent thermometer based on a dual-emitting lanthanide-free MOF hybrid, which is developed by encapsulation of a fluorescent dye into a robust nanocrystalline zirconium-based MOF through a one-pot synthesis approach. The structure and morphology of the hybrid product was characterized by Powder X-ray diffraction (PXRD), N 2 adsorption-desorption measurement and Scanning electron microscopy (SEM). The pore confinement effect well isolates the guest dye molecules and therefore suppresses the nonradiative energy transfer process between dye molecules. The incorporated dye emission is mainly sensitized by the organic linkers within MOF through fluorescence resonance energy transfer. The ratiometric luminescence of the MOF hybrid shows a significant response to temperature due to the thermal-related back energy transfer process from dye molecules and organic linkers, thus can be exploited for self-calibrated temperature sensing. The maximum thermometric sensitivity is 1.19% °C -1 in the physiological temperature range, which is among the highest for the ratiomtric MOF thermometers that operating in 25-45°C. The temperature resolution is better than 0.1°C over the entire operative range (20-60°C). By integrating the advantages of excellent stability, nanoscale nature, and high sensitivity and precision in the physiological temperature range, this dye@MOF hybrid might have potential application in biomedical diagnosis. What' more, this work has expanded the possibility of non-lanthanide luminescent MOF materials for the development of ratiometric temperature sensors. Copyright © 2018

  18. Experimental study of phase change materials for thermal storage in the temperature range of 300–400°C

    Directory of Open Access Journals (Sweden)

    Adinberg R.

    2014-01-01

    Full Text Available Phase change materials (PCM based on inorganic salts having a temperature of fusion between 300 and 400°C, were investigated using a lab scale set-up dedicated for studying latent heat storage for concentrating solar thermal power (CSP technology. This experimental system provides thermal measurements of PCM specimens of about 1000 g under the heating temperature up to 450°C and enables simultaneous investigation of calorimetric properties of the loaded materials and heat transfer effects developed in the thermal storage during the charge and discharge phases. The measurement technique comprised temperature and pressure sensors, a control and data acquisition system and a thermal analysis model used to evaluate the experimental data. Results of the thermochemical tests conducted with a thermal storage medium composed of the ternary eutectic mixture of carbonate salts (34.5% K2CO3–33.4% Na2CO3–32.1% Li2CO3 and Diphyl (synthetic thermal oil, max working temperature 400°C used as the heat transfer fluid are presented and discussed in this paper.

  19. Natural circulation studies in a LBE loop for a wide range of temperature

    International Nuclear Information System (INIS)

    Borgohain, A.; Srivastava, A.K.; Jana, S.S.; Maheshwari, N.K.; Kulkarni, R.D.; Vijayan, P.K.; Tewari, R.; Ram, A. Maruthi; Jha, S.K.

    2016-01-01

    Highlights: • A high temperature Lead Bismuth Eutectic loop named as Kilo Temperature Loop (KTL) has been made. • Natural circulation experimental studies were carried out and reported in the range of 200–780 °C. • The experiments at high temperature were carried in inert atmosphere to avoid oxidation of the loop material. • Theoretical studies are carried out to simulate the loop with natural circulation in primary as well as in the secondary side. • The predictions of the code LeBENC used to simulate the natural circulation in the loop are compared with the experimental results. - Abstract: Lead–Bismuth Eutectic (LBE) is increasingly getting more attention as a coolant for advanced reactor systems. It is also the primary coolant of the Compact High Temperature Reactor (CHTR) being designed at Bhabha Atomic Research Centre (BARC). A high temperature liquid metal loop named as Kilo Temperature Loop (KTL) has been installed at BARC for thermal hydraulics, instrument development and material related studies. Natural circulation experimental studies were carried out for the power range of 200–1200 W in the loop. The corresponding LBE flow rate is calculated to be in the range of 0.075–0.12 kg/s. Transient studies for start-up of natural circulation in the loop, loss of heat sink and step power change have also been carried out. The maximum temperature of the loop operated so far is 1100 °C. A computer code named LeBENC has been developed at BARC to simulate the natural circulation characteristics in closed loops. The salient features of the code include ability to handle non-uniform diameter components, axial thermal conduction in fluid and heat losses from the piping to the environment. The code has been modified to take into account of two natural circulation loops in series so that the natural cooling by argon gas in the secondary side of the loop can be simulated. This paper deals with the description of the loop and its operation. The various

  20. Peculiarities of austenitic state in premartensitic temperature range

    International Nuclear Information System (INIS)

    Sarrak, V.I.; Suvorova, S.O.

    1982-01-01

    A review of works on the study of austenite behaviour in premartensitic temperature range carried out using the investigation methods of resistance to microplastic deformation, mechanical properties and internal friction, is presented. The investigation is carried out using carbon-free iron-nickel alloy N31, alloy 40N24 and alloy 50Kh20N10. It is established that in premartensitic temperature range at a certain temperature Msub(elast.) exceeding by approximately 35 deg C the starting temperature of martensitic transformation, austenite state changes sharply: mechanical instability as to microplastic deformation appears. It manifests itself in an anomalous decrease of resistance to microplastic deformation at the temperature approaching the beginning of martensitic transformation. Martensitic transformation develops under tension in an elastic region. At the temperature above Msub(elast.) martensitic transformation develops only under the effect of plastic deformation. Decrease of temperature of martensitic transformation start as a result of microplastic deformation and subsequent ageing is connected with blocking of possible places of martensite initiation

  1. Peculiarities of austenitic state in premartensitic temperature range

    Energy Technology Data Exchange (ETDEWEB)

    Sarrak, V.I.; Suvorova, S.O.

    A review of works on the study of austenite behaviour in premartensitic temperature range carried out using the investigation methods of resistance to microplastic deformation, mechanical properties and internal friction, is presented. The investigation is carried out using carbon-free iron-nickel alloy N31, alloy 40N24 and alloy 50Kh20N10. It is established that in premartensitic temperature range at a certain temperature Msub(elast.) exceeding by approximately 35 deg C the starting temperature of martensitic transformation austenite state changes sharply: mechanical instability as to microplastic deformation appears. It manifests itself in an anomalous decrease of resistance to microplastic deformation at the temperature approaching the beginning of martensitic transformation. Martensitic transformation develops under tension in an elastic region. At the temperature above Msub(elast.) martensitic transformation develops only under the effect of plastic deformation. Decrease of temperature of martensitic transformation start as a result of microplastic deformation and subsequent ageing is connected with blocking of possible places of martensite initiation.

  2. Promising materials for HTGR high temperature heat exchangers

    International Nuclear Information System (INIS)

    Kuznetsov, E.V.; Tokareva, T.B.; Ryabchenkov, A.V.; Novichkova, O.V.; Starostin, Yu.D.

    1989-01-01

    The service conditions for high-temperature heat-exchangers with helium coolant of HTGRs and requirements imposed on materials for their production are discussed. The choice of nickel-base alloys with solid-solution hardening for long-term service at high temperatures is grounded. Results of study on properties and structure of types Ni-25Cr-5W-5Mo and Ni-20Cr-20W alloy in the temperature range of 900 deg. - 1,000 deg. C are given. The ageing of Ni-25Cr-5W-5Mo alloy at 900 deg. - 950 deg. C results in decreased corrosion-mechanical properties and is caused by the change of structural metal stability. Alloy with 20% tungsten retains a high stability of both structure and properties after prolonged exposure in helium at above temperatures. The alloy has also increased resistance to delayed fracture and low-cycle fatigue at high temperatures. The developed alloy of type Ni-20Cr-20W with microalloying is recommended for production of tubes for HTGR high-temperature heat-exchangers with helium coolant. (author). 3 refs, 8 figs

  3. 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...

  4. Lateral Temperature-Gradient Method for High-Throughput Characterization of Material Processing by Millisecond Laser Annealing.

    Science.gov (United States)

    Bell, Robert T; Jacobs, Alan G; Sorg, Victoria C; Jung, Byungki; Hill, Megan O; Treml, Benjamin E; Thompson, Michael O

    2016-09-12

    A high-throughput method for characterizing the temperature dependence of material properties following microsecond to millisecond thermal annealing, exploiting the temperature gradients created by a lateral gradient laser spike anneal (lgLSA), is presented. Laser scans generate spatial thermal gradients of up to 5 °C/μm with peak temperatures ranging from ambient to in excess of 1400 °C, limited only by laser power and materials thermal limits. Discrete spatial property measurements across the temperature gradient are then equivalent to independent measurements after varying temperature anneals. Accurate temperature calibrations, essential to quantitative analysis, are critical and methods for both peak temperature and spatial/temporal temperature profile characterization are presented. These include absolute temperature calibrations based on melting and thermal decomposition, and time-resolved profiles measured using platinum thermistors. A variety of spatially resolved measurement probes, ranging from point-like continuous profiling to large area sampling, are discussed. Examples from annealing of III-V semiconductors, CdSe quantum dots, low-κ dielectrics, and block copolymers are included to demonstrate the flexibility, high throughput, and precision of this technique.

  5. Effect of calcination temperature on microstructure and electrochemical performance of lithium-rich layered oxide cathode materials

    International Nuclear Information System (INIS)

    Ma, Quanxin; Peng, Fangwei; Li, Ruhong; Yin, Shibo; Dai, Changsong

    2016-01-01

    Highlights: • A series of Li-rich layered oxide cathode materials (Li_1_._2Mn_0_._5_6Ni_0_._1_6Co_0_._0_8O_2) were successfully synthesized via a two-step synthesis method. • The effects of calcination temperature on the cathode materials were researched in detail. • A well-crystallized layered structure was obtained as the calcination temperature increased. • The samples calcined in a range of 850–900 °C exhibited excellent electrochemical performance. - Abstract: Lithium-rich layered oxide cathode materials (Li_1_._2Mn_0_._5_6Ni_0_._1_6Co_0_._0_8O_2 (LLMO)) were synthesized via a two-step synthesis method involving co-precipitation and high-temperature calcination. The effects of calcination temperature on the cathode materials were studied in detail. Structural and morphological characterizations revealed that a well-crystallized layered structure was obtained at a higher calcination temperature. Electrochemical performance evaluation revealed that a cathode material obtained at a calcination temperature of 850 °C delivered a high initial discharge capacity of 266.8 mAh g"−"1 at a 0.1 C rate and a capacity retention rate of 95.8% after 100 cycles as well as excellent rate capability. Another sample calcinated at 900 °C exhibited good cycling stability. It is concluded that the structural stability and electrochemical performance of Li-rich layered oxide cathode materials were strongly dependent on calcination temperatures. The results suggest that a calcination temperature in a range of 850–900 °C could promote electrochemical performance of this type of cathode materials.

  6. Effect of calcination temperature on microstructure and electrochemical performance of lithium-rich layered oxide cathode materials

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Quanxin; Peng, Fangwei; Li, Ruhong; Yin, Shibo; Dai, Changsong, E-mail: changsd@hit.edu.cn

    2016-11-15

    Highlights: • A series of Li-rich layered oxide cathode materials (Li{sub 1.2}Mn{sub 0.56}Ni{sub 0.16}Co{sub 0.08}O{sub 2}) were successfully synthesized via a two-step synthesis method. • The effects of calcination temperature on the cathode materials were researched in detail. • A well-crystallized layered structure was obtained as the calcination temperature increased. • The samples calcined in a range of 850–900 °C exhibited excellent electrochemical performance. - Abstract: Lithium-rich layered oxide cathode materials (Li{sub 1.2}Mn{sub 0.56}Ni{sub 0.16}Co{sub 0.08}O{sub 2} (LLMO)) were synthesized via a two-step synthesis method involving co-precipitation and high-temperature calcination. The effects of calcination temperature on the cathode materials were studied in detail. Structural and morphological characterizations revealed that a well-crystallized layered structure was obtained at a higher calcination temperature. Electrochemical performance evaluation revealed that a cathode material obtained at a calcination temperature of 850 °C delivered a high initial discharge capacity of 266.8 mAh g{sup −1} at a 0.1 C rate and a capacity retention rate of 95.8% after 100 cycles as well as excellent rate capability. Another sample calcinated at 900 °C exhibited good cycling stability. It is concluded that the structural stability and electrochemical performance of Li-rich layered oxide cathode materials were strongly dependent on calcination temperatures. The results suggest that a calcination temperature in a range of 850–900 °C could promote electrochemical performance of this type of cathode materials.

  7. A sub-circuit MOSFET model with a wide temperature range including cryogenic temperature

    Energy Technology Data Exchange (ETDEWEB)

    Jia Kan; Sun Weifeng; Shi Longxing, E-mail: jiakan.01@gmail.com [National ASIC System Engineering Research Center, Southeast University, Nanjing 210096 (China)

    2011-06-15

    A sub-circuit SPICE model of a MOSFET for low temperature operation is presented. Two resistors are introduced for the freeze-out effect, and the explicit behavioral models are developed for them. The model can be used in a wide temperature range covering both cryogenic temperature and regular temperatures. (semiconductor devices)

  8. Symposium on high temperature and materials chemistry

    International Nuclear Information System (INIS)

    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

  9. 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.

  10. Critical current measurements of high-temperature superconducting short samples at a wide range of temperatures and magnetic fields

    Science.gov (United States)

    Ma, Hongjun; Liu, Huajun; Liu, Fang; Zhang, Huahui; Ci, Lu; Shi, Yi; Lei, Lei

    2018-01-01

    High-Temperature Superconductors (HTS) are potential materials for high-field magnets, low-loss transmission cables, and Superconducting Magnetic Energy Storage (SMES) due to their high upper critical magnetic field (Hc2) and critical temperature (Tc). The critical current (Ic) of HTS, which is one of the most important parameters for superconductor application, depends strongly on the magnetic fields and temperatures. A new Ic measurement system that can carry out accurate Ic measurement for HTS short samples with various temperatures (4.2-80 K), magnetic fields (0-14 T), and angles of the magnetic field (0°-90°) has been developed. The Ic measurement system mainly consists of a measurement holder, temperature-control system, background magnet, test cryostat, data acquisition system, and DC power supply. The accuracy of temperature control is better than ±0.1 K over the 20-80 K range and ±0.05 K when measured below 20 K. The maximum current is over 1000 A with a measurement uncertainty of 1%. The system had been successfully used for YBa2Cu3O7-x(YBCO) tapes Ic determination with different temperatures and magnetic fields.

  11. Critical current measurements of high-temperature superconducting short samples at a wide range of temperatures and magnetic fields.

    Science.gov (United States)

    Ma, Hongjun; Liu, Huajun; Liu, Fang; Zhang, Huahui; Ci, Lu; Shi, Yi; Lei, Lei

    2018-01-01

    High-Temperature Superconductors (HTS) are potential materials for high-field magnets, low-loss transmission cables, and Superconducting Magnetic Energy Storage (SMES) due to their high upper critical magnetic field (H c2 ) and critical temperature (T c ). The critical current (I c ) of HTS, which is one of the most important parameters for superconductor application, depends strongly on the magnetic fields and temperatures. A new I c measurement system that can carry out accurate I c measurement for HTS short samples with various temperatures (4.2-80 K), magnetic fields (0-14 T), and angles of the magnetic field (0°-90°) has been developed. The I c measurement system mainly consists of a measurement holder, temperature-control system, background magnet, test cryostat, data acquisition system, and DC power supply. The accuracy of temperature control is better than ±0.1 K over the 20-80 K range and ±0.05 K when measured below 20 K. The maximum current is over 1000 A with a measurement uncertainty of 1%. The system had been successfully used for YBa 2 Cu 3 O 7-x (YBCO) tapes I c determination with different temperatures and magnetic fields.

  12. High temperature brazing of reactor materials

    International Nuclear Information System (INIS)

    Orlov, A.V.; Nechaev, V.A.; Rybkin, B.V.; Ponimash, I.D.

    1990-01-01

    Application of high-temperature brazing for joining products of such materials as molybdenum, tungsten, zirconium, beryllium, magnesium, nickel and aluminium alloys, graphite ceramics etc. is described. Brazing materials composition and brazed joints properties are presented. A satisfactory strength of brazed joints is detected under reactor operation temperatures and coolant and irradiation effect

  13. Recrystallization kinetics of warm-rolled tungsten in the temperature range 1150-1350 °C

    Science.gov (United States)

    Alfonso, A.; Juul Jensen, D.; Luo, G.-N.; Pantleon, W.

    2014-12-01

    Pure tungsten is a potential candidate material for the plasma-facing first wall and the divertor of fusion reactors. Both parts have to withstand high temperatures during service. This will alter the microstructure of the material by recovery, recrystallization and grain growth and will cause degradation in material properties as a loss in mechanical strength and embrittlement. The thermal stability of a pure tungsten plate warm-rolled to 67% thickness reduction was investigated by long-term isothermal annealing in the temperature range between 1150 °C and 1350 °C up to 2200 h. Changes in the mechanical properties during annealing are quantified by Vickers hardness measurements. They are described concisely by classical kinetic models for recovery and recrystallization. The observed time spans for recrystallization and the obtained value for the activation energy of the recrystallization process indicate a sufficient thermal stability of the tungsten plate during operation below 1075 °C.

  14. Platform for high temperature materials (PHiTEM)

    International Nuclear Information System (INIS)

    Baluc, N.; Hoffelner, W.; Michler, J.

    2007-01-01

    Advanced energy power systems like Generation IV fission reactors, thermonuclear fusion reactors, solar thermal/solar chemical reactors, gas turbines and coal gasification systems require materials that can operate at high temperatures in extreme environments: irradiation, corrosion, unidirectional and cyclic loads. On the path to development of new and adequate high temperature materials, understanding of damage formation and evolution and of damage effects is indispensable. Damage of materials in components takes place on different time and length scales. Component failure is usually a macroscopic event. Macroscopic material properties and their changes with time (e.g., hardening, creep embrittlement, corrosion) are determined by the micro- to nano-properties of the material. The multi scale is an ambitious and challenging attempt to take these facts into consideration by developing an unified model of the material behaviour. This requires, however, dedicated tools to test and analyse materials on different scales. The platform for high temperatures materials is being set up within the framework of collaboration between the EPFL, the PSI and the EMPA. It has three main goals: 1) Establish a platform that allows the multi scale characterization of relationships between microstructure and mechanical properties of advanced, high temperature materials, with a focus on irradiated, i.e. radioactive, materials, by combining the use of a focused ion beam and a nano indentation device with multi scale modelling and simulations. 2) Use the methods developed and the results gained for existing materials for developing improved high temperature materials to be used in advanced and sustainable future energy power plants. 3) Become an attractive partner for industry by providing a wide knowledge base, flexibility in answering technical questions and skills to better understand damage in already existing plants and to support development of new products at the industrial scale

  15. Characterization of piezoelectric materials for simultaneous strain and temperature sensing for ultra-low frequency applications

    International Nuclear Information System (INIS)

    Islam, Mohammad Nouroz; Seethaler, Rudolf; Alam, M Shahria

    2015-01-01

    Piezoelectric materials are used extensively in a number of sensing applications ranging from aerospace industries to medical diagnostics. Piezoelectric materials generate charge when they are subjected to strain. However, since measuring charge is difficult at low frequencies, traditional piezoelectric sensors are limited to dynamic applications. In this research an alternative technique is proposed to determine static strain that relies upon the measurement of piezoelectric capacitance and resistance using piezoelectric sensors. To demonstrate the validity of this approach, the capacitance and resistance of a piezoelectric patch sensor was characterized for a wide range of strain and temperature. The study shows that the piezoelectric capacitance is sensitive to both strain and temperature while the resistance is mostly dependent on the temperature variation. The findings can be implemented to obtain thermally compensated static strain from piezoelectric sensors, which does not require an additional temperature sensor. (paper)

  16. Temperature and loading frequency effects of fatigue crack growth in HDPE pipe material

    International Nuclear Information System (INIS)

    Merah, N.; Khan, Z.; Bazoune, A.; Saghir, F.

    2006-01-01

    High density polyethylene (HDPE) pipes are being extensively used for gas, water, sewage and waste water distribution systems. Laboratory tests appear to show that HDPE is more able to suppress rapid crack propagation, while remaining somehow resistant to slow crack growth failures observed in service. Procedures for estimating pipe life in service have been established by making use of fatigue crack growth (FCG) results. These procedures are concerned mainly with room temperature. Applications with some safety factor to include the temperature effect. Use of HDPE pipes in water and gas distribution in the Gulf area has seen a net increase. This study addresses the combined effects of temperature and frequency on FCG properties of commercial HDPE pipe material. FCG accelerated tests were conducted on single-etch notch (SEN) specimens in the temperature range of -10 to 70C at frequencies ranging from 0.1 to 50 Hz. The FCG tests are conducted at a stress amplitude level approximately 1/4 of room temperature yield stress and crack growth behavior was investigated using linear elastic fracture mechanics concepts. The stress intensity range delta K gave satisfactory correlation of crack, growth rate (da/dN) at the temperatures of -10, 0, 23 and 40C and at frequencies of 0.1, 1, and 50 Hz. The crack growth resistance was found to decrease with increase in test temperature and decrease growth resistance was found to decrease with increase in test temperature and decrease with frequency. For 70C no crack propagation was observed, the failure was observed to occur by collapse or generalized yielding. Fractographic analyses results are used to explain temperature and frequency effects on FCG. The effect of temperature on da/dN for HDPE material was investigated by considering the variation of mechanical properties with temperature. Master curves were developed by normalizing delta K yield stress. (author)

  17. Results of radiation tests at cryogenic temperature on some selected organic materials for the LHC

    International Nuclear Information System (INIS)

    Schoenbacher, H.; Szeless, B.; Tavlet, M.; Humer, K.; Weber, H.W.

    1996-01-01

    Future multi-TeV particle accelerators like the CERN Large Hadron Collider (LHC) will use superconducting magnets where organic materials will be exposed to high radiation levels at temperatures as low as 2 K. A representative selection of organic materials comprising insulating films, cable insulations, and epoxy-type impregnated resins were exposed to neutron and gamma radiation of a nuclear reactor. Depending on the type of materials, the integrated radiation doses varied between 180 kGy and 155 MGy. During irradiation, the samples were kept close to the boiling temperature of liquid nitrogen i.e. ∼ 80 K and thereafter stored in liquid nitrogen and transferred at the same temperature into the testing device for measurement of tensile and flexural strength. Tests were carried out on the same materials at similar dose rates at room temperature, and the results were compared with those obtained at cryogenic temperature. They show that, within the selected dose range, a number of organic materials are suitable for use in the radiation field of the LHC at cryogenic temperature. (orig.)

  18. Measuring Systems for Thermometer Calibration in Low-Temperature Range

    Science.gov (United States)

    Szmyrka-Grzebyk, A.; Lipiński, L.; Manuszkiewicz, H.; Kowal, A.; Grykałowska, A.; Jancewicz, D.

    2011-12-01

    The national temperature standard for the low-temperature range between 13.8033 K and 273.16 K has been established in Poland at the Institute of Low Temperature and Structure Research (INTiBS). The standard consists of sealed cells for realization of six fixed points of the International Temperature Scale of 1990 (ITS-90) in the low-temperature range, an adiabatic cryostat and Isotech water and mercury triple-point baths, capsule standard resistance thermometers (CSPRT), and AC and DC bridges with standard resistors for thermometers resistance measurements. INTiBS calibrates CSPRTs at the low-temperature fixed points with uncertainties less than 1 mK. In lower temperature range—between 2.5 K and about 25 K — rhodium-iron (RhFe) resistance thermometers are calibrated by comparison with a standard which participated in the EURAMET.T-K1.1 comparison. INTiBS offers a calibration service for industrial platinum resistance thermometers and for digital thermometers between 77 K and 273 K. These types of thermometers may be calibrated at INTiBS also in a higher temperature range up to 550°C. The Laboratory of Temperature Standard at INTiBS acquired an accreditation from the Polish Centre for Accreditation. A management system according to EN ISO/IEC 17025:2005 was established at the Laboratory and presented on EURAMET QSM Forum.

  19. High temperature materials characterization

    Science.gov (United States)

    Workman, Gary L.

    1990-01-01

    A lab facility for measuring elastic moduli up to 1700 C was constructed and delivered. It was shown that the ultrasonic method can be used to determine elastic constants of materials from room temperature to their melting points. The ease in coupling high frequency acoustic energy is still a difficult task. Even now, new coupling materials and higher power ultrasonic pulsers are being suggested. The surface was only scratched in terms of showing the full capabilities of either technique used, especially since there is such a large learning curve in developing proper methodologies to take measurements into the high temperature region. The laser acoustic system does not seem to have sufficient precision at this time to replace the normal buffer rod methodology.

  20. 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

  1. 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.

  2. Atmospheric Plasma Spraying Low-Temperature Cathode Materials for Solid Oxide Fuel Cells

    Science.gov (United States)

    Harris, J.; Kesler, O.

    2010-01-01

    Atmospheric plasma spraying (APS) is attractive for manufacturing solid oxide fuel cells (SOFCs) because it allows functional layers to be built rapidly with controlled microstructures. The technique allows SOFCs that operate at low temperatures (500-700 °C) to be fabricated by spraying directly onto robust and inexpensive metallic supports. However, standard cathode materials used in commercial SOFCs exhibit high polarization resistances at low operating temperatures. Therefore, alternative cathode materials with high performance at low temperatures are essential to facilitate the use of metallic supports. Coatings of lanthanum strontium cobalt ferrite (LSCF) were fabricated on steel substrates using axial-injection APS. The thickness and microstructure of the coating layers were evaluated, and x-ray diffraction analysis was performed on the coatings to detect material decomposition and the formation of undesired phases in the plasma. These results determined the envelope of plasma spray parameters in which coatings of LSCF can be manufactured, and the range of conditions in which composite cathode coatings could potentially be manufactured.

  3. 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.

  4. 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

    The worldwide development of fuel cells and electrolysers has so far almost exclusively addressed either the low temperature window (20-200 °C) or the high temperature window (600-1000 °C). This work concerns the development of key materials and components of a new generation of fuel cells...... 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...... might be used. One of the key materials in the fuel cell and electrolyser systems is the electrolyte. Proton conducting materials such as cesium hydrogen phosphates, zirconium hydrogen phosphates and tin pyrophosphates have been investigated by others and have shown interesting potential....

  5. Note: A wide temperature range MOKE system with annealing capability.

    Science.gov (United States)

    Chahil, Narpinder Singh; Mankey, G J

    2017-07-01

    A novel sample stage integrated with a longitudinal MOKE system has been developed for wide temperature range measurements and annealing capabilities in the temperature range 65 K temperatures without adversely affecting the cryostat and minimizes thermal drift in position. In this system the hysteresis loops of magnetic samples can be measured simultaneously while annealing the sample in a magnetic field.

  6. Evaluation of the local temperature of conductive filaments in resistive switching materials

    International Nuclear Information System (INIS)

    Yalon, E; Cohen, S; Gavrilov, A; Ritter, D

    2012-01-01

    The resistive switching effect in metal oxides and other dielectric materials is among the leading future non-volatile memory technologies. Resistive switching is widely ascribed to the formation and rupture of conductive filaments in the oxide, which are generated by temperature-enhanced nano-scale ion migration or other thermal effects. In spite of the central role of the local filament temperature on the switching effect, as well as on the conduction and reliability physics, no measurement methods of the filament temperature are yet available. In this work, we report on a method for evaluating the conducting filament temperature, using a metal–insulator–semiconductor bipolar transistor structure. The filament temperature is obtained by analyzing the thermal excitation rate of electrons from the filament Fermi level into the conduction band of a p-type semiconductor electrode. Measurements were carried out to obtain the conductive filament temperature in hafnia at varying ambient temperatures in the range of 3–300 K. Significant Joule heating of the filament was observed across the entire measured ambient temperature range. The extracted temperatures provide physical insight into the resistive switching effect. (paper)

  7. Extending the temperature range of the HTR

    International Nuclear Information System (INIS)

    Balcomb, J.D.; Wagner, P.

    1975-01-01

    The operating temperature of the high temperature helium-cooled reactor can be increased in a number of ways in order to provide higher temperature nuclear heat for various industrial processes. Modifications are of two types: 1) decrease in the temperature difference between the maximum coated particle fuel temperature and the mean exit gas temperature, and 2) increased maximum coated particle temperature. Gains in the latter category are limited by fission product diffusion into the gas steam and increases greater than 100 0 K are not forseen. Increases in the former category, however, are readily made and a variety of modifications are proposed as follows: incorporation of coated particles in the fuel matrix; use of a more finely-divided fuel coolant hole geometry to increase heat transfer coefficients and reduce conduction temperature differences; large increases in the fuel matrix graphite thermal conductivity (to about 50 W/m 0 K) to reduce conduction temperature differences; and modifications to the core distribution, both radially and axially. By such means the exit gas temperature can be increased to the range of 1200 0 K to 1600 0 K. (author)

  8. Effects of molten material temperatures and coolant temperatures on vapor explosion

    Institute of Scientific and Technical Information of China (English)

    LI Tianshu; YANG Yanhua; YUAN Minghao; HU Zhihua

    2007-01-01

    An observable experiment facility for low-temperature molten materials to be dropped into water was set up in this study to investigate the mechanism of the vapor explosion. The effect of the fuel and coolant interaction(FCI) on the vapor explosion during the severe accidents of a fission nuclear reactor has been studied. The experiment results showed that the molten material temperature has an important effect on the vapor explosion behavior and pressure. The increase of the coolant temperature would decrease the pressure of the vapor explosion.

  9. Characterization of sapphire: For its material properties at high temperatures

    Science.gov (United States)

    Bal, Harman Singh

    There are numerous needs for sensing, one of which is in pressure sensing for high temperature application such as combustion related process and embedded in aircraft wings for reusable space vehicles. Currently, silicon based MEMS technology is used for pressure sensing. However, due to material properties the sensors have a limited range of approximately 600 °C which is capable of being pushed towards 1000 °C with active cooling. This can introduce reliability issues when you add more parts and high flow rates to remove large amounts of heat. To overcome this challenge, sapphire is investigated for optical based pressure transducers at temperatures approaching 1400 °C. Due to its hardness and chemical inertness, traditional cutting and etching methods used in MEMS technology are not applicable. A method that is being investigated as a possible alternative is laser machining using a picosecond laser. In this research, we study the material property changes that occur from laser machining and quantify the changes with the experimental results obtained by testing sapphire at high-temperature with a standard 4-point bending set-up.

  10. Recrystallization kinetics of warm-rolled tungsten in the temperature range 1150–1350 °C

    Energy Technology Data Exchange (ETDEWEB)

    Alfonso, A., E-mail: aalz@dtu.dk [Section of Materials and Surface Engineering, Department of Mechanical Engineering, Technical University of Denmark, 2800 Lyngby (Denmark); Sino-Danish Center for Education and Research (China); Sino-Danish Center for Education and Research (Denmark); Juul Jensen, D. [Danish-Chinese Center for Nanometals, Section of Materials Science and Advanced Characterization, Department of Wind Energy, Technical University of Denmark, Risø Campus, 4000 Roskilde (Denmark); Sino-Danish Center for Education and Research (China); Sino-Danish Center for Education and Research (Denmark); Luo, G.-N. [Fusion Reactor Materials Science and Technology Division, Institute of Plasma Physics, Chinese Academy of Sciences, 230031 Hefei, Anhui (China); Sino-Danish Center for Education and Research (China); Sino-Danish Center for Education and Research (Denmark); Pantleon, W. [Section of Materials and Surface Engineering, Department of Mechanical Engineering, Technical University of Denmark, 2800 Lyngby (Denmark); Association EURATOM-DTU (Denmark); Sino-Danish Center for Education and Research (China); Sino-Danish Center for Education and Research (Denmark)

    2014-12-15

    Pure tungsten is a potential candidate material for the plasma-facing first wall and the divertor of fusion reactors. Both parts have to withstand high temperatures during service. This will alter the microstructure of the material by recovery, recrystallization and grain growth and will cause degradation in material properties as a loss in mechanical strength and embrittlement. The thermal stability of a pure tungsten plate warm-rolled to 67% thickness reduction was investigated by long-term isothermal annealing in the temperature range between 1150 °C and 1350 °C up to 2200 h. Changes in the mechanical properties during annealing are quantified by Vickers hardness measurements. They are described concisely by classical kinetic models for recovery and recrystallization. The observed time spans for recrystallization and the obtained value for the activation energy of the recrystallization process indicate a sufficient thermal stability of the tungsten plate during operation below 1075 °C.

  11. Recrystallization kinetics of warm-rolled tungsten in the temperature range 1150–1350 °C

    International Nuclear Information System (INIS)

    Alfonso, A.; Juul Jensen, D.; Luo, G.-N.; Pantleon, W.

    2014-01-01

    Pure tungsten is a potential candidate material for the plasma-facing first wall and the divertor of fusion reactors. Both parts have to withstand high temperatures during service. This will alter the microstructure of the material by recovery, recrystallization and grain growth and will cause degradation in material properties as a loss in mechanical strength and embrittlement. The thermal stability of a pure tungsten plate warm-rolled to 67% thickness reduction was investigated by long-term isothermal annealing in the temperature range between 1150 °C and 1350 °C up to 2200 h. Changes in the mechanical properties during annealing are quantified by Vickers hardness measurements. They are described concisely by classical kinetic models for recovery and recrystallization. The observed time spans for recrystallization and the obtained value for the activation energy of the recrystallization process indicate a sufficient thermal stability of the tungsten plate during operation below 1075 °C

  12. Material Properties at Low Temperature

    International Nuclear Information System (INIS)

    Duthil, P

    2014-01-01

    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

  13. 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.

  14. Material Properties at Low Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Duthil, P [Orsay, IPN (France)

    2014-07-01

    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.

  15. Heat treated 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

    2012-08-21

    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.

  16. Performance of candidate gas turbine abradeable seal materials in high temperature combustion atmospheres

    Energy Technology Data Exchange (ETDEWEB)

    Simms, N.J. [Cranfield University, Power Generation Technology Centre, Cranfield, Beds, MK43 0AL (United Kingdom); Norton, J.F. [Cranfield University, Power Generation Technology Centre, Cranfield, Beds, MK43 0AL (United Kingdom); Consultant in Corrosion Science and Technology, Hemel Hempstead, Herts HP1 1SR (United Kingdom); McColvin, G. [Siemens Industrial Turbines Ltd., Lincoln, LN5 7FD (United Kingdom)

    2005-11-01

    The development of abradeable gas turbine seals for higher temperature duties has been the target of an EU-funded R and D project, ADSEALS, with the aim of moving towards seals that can withstand surface temperatures as high as {proportional_to} 1100 C for periods of at least 24,000 h. The ADSEALS project has investigated the manufacturing and performance of a number of alternative materials for the traditional honeycomb seal design and novel alternative designs. This paper reports results from two series of exposure tests carried out to evaluate the oxidation performance of the seal structures in combustion gases and under thermal cycling conditions. These investigations formed one part of the evaluation of seal materials that has been carried out within the ADSEALS project. The first series of three tests, carried out for screening purposes, exposed candidate abradeable seal materials to a simulated natural gas combustion environment at temperatures within the range 1050-1150 C in controlled atmosphere furnaces for periods of up to {proportional_to} 2,500 h with fifteen thermal cycles. The samples were thermally cycled to room temperature on a weekly basis to enable the progress of the degradation to be monitored by mass change and visual observation, as well as allowing samples to be exchanged at planned intervals. The honeycombs were manufactured from PM2000 and Haynes 214. The backing plates for the seal constructions were manufactured from Haynes 214. Some seals contained fillers or had been surface treated (e.g. aluminised). The second series of three tests were carried out in a natural gas fired ribbon furnace facility that allowed up to sixty samples of candidate seal structures (including honeycombs, hollow sphere structures and porous ceramics manufactured from an extended range of materials including Aluchrom YHf, PM2Hf, Haynes 230, IN738LC and MarM247) to be exposed simultaneously to a stream of hot combustion gas. In this case the samples were cooled

  17. Elevated temperature erosion studies on some materials for high temperature applications

    International Nuclear Information System (INIS)

    Zhou Jianren.

    1991-01-01

    The surface degradation of materials due to high temperature erosion or combined erosion corrosion is a serious problem in many industrial and aeronautical applications. As such, it has become an important design consideration in many situations. The materials investigated in the present studies are stainless steels, Ti-6Al-4V, alumina ceramics, with and without silicate glassy phase, and zirconia. These are some of the potential materials for use in the high temperature erosive-corrosive environments. The erosion or erosion-corrosion experiments were performed in a high temperature sand-blast type of test rig. The variables studied included the temperature, material composition, heat treatment condition, impingement velocity and angle, erodent concentration, etc. The morphological features of the eroded or eroded-corroded surfaces, substrate deformation, and oxide characteristics were studied by optical and scanning electron microscopy, X-ray diffraction, energy dispersive X-ray spectroscopy, thermogravimetric analysis. The scratch test, single ball impact, and indentation tests were used to understand the behavior of oxide film in particle impacts. Based on these studies, the understanding of the mechanisms involved in the mechanical or combined mechanical and chemical actions in erosion was developed

  18. 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

  19. Materials corrosion and protection at high temperatures

    International Nuclear Information System (INIS)

    Balbaud, F.; Desgranges, Clara; Martinelli, Laure; Rouillard, Fabien; Duhamel, Cecile; Marchetti, Loic; Perrin, Stephane; Molins, Regine; Chevalier, S.; Heintz, O.; David, N.; Fiorani, J.M.; Vilasi, M.; Wouters, Y.; Galerie, A.; Mangelinck, D.; Viguier, B.; Monceau, D.; Soustelle, M.; Pijolat, M.; Favergeon, J.; Brancherie, D.; Moulin, G.; Dawi, K.; Wolski, K.; Barnier, V.; Rebillat, F.; Lavigne, O.; Brossard, J.M.; Ropital, F.; Mougin, J.

    2011-01-01

    This book was made from the lectures given in 2010 at the thematic school on 'materials corrosion and protection at high temperatures'. It gathers the contributions from scientists and engineers coming from various communities and presents a state-of-the-art of the scientific and technological developments concerning the behaviour of materials at high temperature, in aggressive environments and in various domains (aerospace, nuclear, energy valorization, and chemical industries). It supplies pedagogical tools to grasp high temperature corrosion thanks to the understanding of oxidation mechanisms. It proposes some protection solutions for materials and structures. Content: 1 - corrosion costs; macro-economical and metallurgical approach; 2 - basic concepts of thermo-chemistry; 3 - introduction to the Calphad (calculation of phase diagrams) method; 4 - use of the thermodynamic tool: application to pack-cementation; 5 - elements of crystallography and of real solids description; 6 - diffusion in solids; 7 - notions of mechanics inside crystals; 8 - high temperature corrosion: phenomena, models, simulations; 9 - pseudo-stationary regime in heterogeneous kinetics; 10 - nucleation, growth and kinetic models; 11 - test experiments in heterogeneous kinetics; 12 - mechanical aspects of metal/oxide systems; 13 - coupling phenomena in high temperature oxidation; 14 - other corrosion types; 15 - methods of oxidized surfaces analysis at micro- and nano-scales; 16 - use of SIMS in the study of high temperature corrosion of metals and alloys; 17 - oxidation of ceramics and of ceramic matrix composite materials; 18 - protective coatings against corrosion and oxidation; 19 - high temperature corrosion in the 4. generation of nuclear reactor systems; 20 - heat exchangers corrosion in municipal waste energy valorization facilities; 21 - high temperature corrosion in oil refining and petrochemistry; 22 - high temperature corrosion in new energies industry. (J.S.)

  20. INVESTIGATION OF THE FREQUENCY-TEMPERATURE RELATIONSHIP OF THE DIELECTRIC PERMITTIVITY OF THE PZT PIEZOCERAMICS IN THE LOW FREQUENCY RANGE

    Directory of Open Access Journals (Sweden)

    A. I. ZOLOTAREVSKIY

    2018-05-01

    Full Text Available Purpose. To investigate the frequency-temperature relationship of the dielectric permittivity of PZT piezoceramics in the low frequency range. Methodology. To obtain the frequency-temperature relationship of the dielectric permittivity of the PZT piezoceramics, a technique was used to determine the capacitance of the capacitor, between which plates the sample was placed. The value of the dielectric permittivity of the sample was calculated from the capacitor capacitance obtained. Findings. The frequency-temperature relationship of the dielectric permittivity of the PZT piezoceramics in the low frequency range has been obtained by the authors. The dielectric permittivity is not practically related to the frequency of the alternating voltage at a low temperature, with increasing in temperature its value increases and frequency relationship is observed. The temperature relationship of the dielectric permittivity of the PZT piezoceramics is satisfactorily described by the exponential functional dependence in the low-temperature range. The activation energy of the PZT piezoceramics polarization is determined from the graph of the dependence of the logarithm of the dielectric permittivity upon the inverse temperature. Different values of the activation energy for the two temperature regions prove on the existence of different mechanisms of the PZT piezoceramics polarization in the temperature range being investigated. Originality. The authors investigated the frequency-temperature relationship of the dielectric permittivity of the PZT piezoceramics in the low-frequency range. It is established that the temperature relationship of the dielectric permittivity of the PZT piezoceramics is satisfactorily described by an exponential functional relationship in the lowtemperature range. The activation energy of polarization is determined for two temperature sections. Practical value. The research results can be used to study the mechanism of polarization of

  1. Heart rate, multiple body temperature, long-range and long-life telemetry system for free-ranging animals

    Science.gov (United States)

    Lund, G. F.; Westbrook, R. M.; Fryer, T. B.

    1980-01-01

    The design details and rationale for a versatile, long-range, long-life telemetry data acquisition system for heart rates and body temperatures at multiple locations from free-ranging animals are presented. The design comprises an implantable transmitter for short to medium range transmission, a receiver retransmitter collar to be worn for long-range transmission, and a signal conditioner interface circuit to assist in signal discrimination and demodulation of receiver or tape-recorded audio outputs. Implanted electrodes are used to obtain an ECG, from which R-wave characteristics are selected to trigger a short RF pulse. Pulses carrying heart rate information are interrupted periodically by a series of pulse interval modulated RF pulses conveying temperature information sensed at desired locations by thermistors. Pulse duration and pulse sequencing are used to discriminate between heart rate and temperature pulses as well as radio frequency interference. The implanted transmitter may be used alone for medium and short-range tracking, or with a receiver-transmitter collar that employs commercial tracking equipment for transmissions of up to 12 km. A system prototype has been tested on a dog.

  2. Dielectric characterization of materials at microwave frequency range

    Directory of Open Access Journals (Sweden)

    J. de los Santos

    2003-01-01

    Full Text Available In this study a coaxial line was used to connect a microwave-frequency Network Analyzer and a base moving sample holder for dielectric characterization of ferroelectric materials in the microwave range. The main innovation of the technique is the introduction of a special sample holder that eliminates the air gap effect by pressing sample using a fine pressure system control. The device was preliminary tested with alumina (Al2O3 ceramics and validated up to 2 GHz. Dielectric measurements of lanthanum and manganese modified lead titanate (PLTM ceramics were carried out in order to evaluate the technique for a high permittivity material in the microwave range. Results showed that such method is very useful for materials with high dielectric permittivities, which is generally a limiting factor of other techniques in the frequency range from 50 MHz to 2 GHz.

  3. Bioinspired large-scale aligned porous materials assembled with dual temperature gradients.

    Science.gov (United States)

    Bai, Hao; Chen, Yuan; Delattre, Benjamin; Tomsia, Antoni P; Ritchie, Robert O

    2015-12-01

    Natural materials, such as bone, teeth, shells, and wood, exhibit outstanding properties despite being porous and made of weak constituents. Frequently, they represent a source of inspiration to design strong, tough, and lightweight materials. Although many techniques have been introduced to create such structures, a long-range order of the porosity as well as a precise control of the final architecture remain difficult to achieve. These limitations severely hinder the scale-up fabrication of layered structures aimed for larger applications. We report on a bidirectional freezing technique to successfully assemble ceramic particles into scaffolds with large-scale aligned, lamellar, porous, nacre-like structure and long-range order at the centimeter scale. This is achieved by modifying the cold finger with a polydimethylsiloxane (PDMS) wedge to control the nucleation and growth of ice crystals under dual temperature gradients. Our approach could provide an effective way of manufacturing novel bioinspired structural materials, in particular advanced materials such as composites, where a higher level of control over the structure is required.

  4. Advanced ceramic material for high temperature turbine tip seals

    Science.gov (United States)

    Solomon, N. G.; Vogan, J. W.

    1978-01-01

    Ceramic material systems are being considered for potential use as turbine blade tip gas path seals at temperatures up to 1370 1/4 C. Silicon carbide and silicon nitride structures were selected for study since an initial analysis of the problem gave these materials the greatest potential for development into a successful materials system. Segments of silicon nitride and silicon carbide materials over a range of densities, processed by various methods, a honeycomb structure of silicon nitride and ceramic blade tip inserts fabricated from both materials by hot pressing were tested singly and in combination. The evaluations included wear under simulated engine blade tip rub conditions, thermal stability, impact resistance, machinability, hot gas erosion and feasibility of fabrication into engine components. The silicon nitride honeycomb and low-density silicon carbide using a selected grain size distribution gave the most promising results as rub-tolerant shroud liners. Ceramic blade tip inserts made from hot-pressed silicon nitride gave excellent test results. Their behavior closely simulated metal tips. Wear was similar to that of metals but reduced by a factor of six.

  5. Dimethyl terephthalate (DMT) as a candidate phase change material for high temperature thermal energy storage

    Energy Technology Data Exchange (ETDEWEB)

    Kuecuekaltun, Engin [Advansa Sasa Polyester San, A.S., Adana (Turkey); Paksoy, Halime; Bilgin, Ramazan; Yuecebilgic, Guezide [Cukurova Univ., Adana (Turkey). Chemistry Dept.; Evliya, Hunay [Cukurova Univ., Adana (Turkey). Center for Environmental Research

    2010-07-01

    Thermal energy storage at elevated temperatures, particularly in the range of 120-250 C is of interest with a significant potential for industrial applications that use process steam at low or intermediate pressures. At given temperature range there are few studies on thermal energy storage materials and most of them are dedicated to sensible heat. In this study, Dimethyl Terephthalate - DMT (CAS No: 120-61-6) is investigated as a candidate phase change material (PCM) for high temperature thermal energy storage. DMT is a monomer commonly used in Polyethylene terephtalate industry and has reasonable cost and availability. The Differential Scanning Calorimetry (DSC) analysis and heating cooling curves show that DMT melts at 140-146 C within a narrow window. Supercooling that was detected in DSC results was not observed in the cooling curve measurements made with a larger sample. With a latent heat of 193 J/g, DMT is a candidate PCM for high temperature storage. Potential limitations such as, low thermal conductivity and sublimation needs further investigation. (orig.)

  6. Comparison of thermal properties of fish collagen and bovine collagen in the temperature range 298-670K.

    Science.gov (United States)

    Gauza-Włodarczyk, Marlena; Kubisz, Leszek; Mielcarek, Sławomir; Włodarczyk, Dariusz

    2017-11-01

    The increased interest in fish collagen is a consequence of the risk of exposure to Creutzfeld-Jacob disease (CJD) and the bovine spongiform encephalopathy (BSE), whose occurrence is associated with prions carried by bovine collagen. Collagen is the main biopolymer in living organisms and the main component of the skin and bones. Until the discovery of the BSE, bovine collagen had been widely used. The BSE epidemic increased the interest in new sources of collagen such as fish skin collagen (FSC) and its properties. Although the thermal properties of collagen originating from mammals have been well described, less attention has been paid to the thermal properties of FSC. Denaturation temperature is a particularly important parameter, depending on the collagen origin and hydration level. In the reported experiment, the free water and bound water release processes along with thermal denaturation process were studied by means of the differential scanning calorimetry (DSC). Measurements were carried out using a DSC 7 instrument (Elmer-Perkin), in the temperature range 298-670K. The study material was FSC derived by acidic hydration method. The bovine Achilles tendon (BAT) collagen type I was used as the control material. The thermograms recorded revealed both, exothermic and endothermic peaks. For both materials, the peaks in the temperature range of 330-360K were assigned to the release of free water and bound water. The denaturation temperatures of FSC and BAT collagen were determined as 420K and 493K, respectively. Thermal decomposition process was observed at about 500K for FSC and at about 510K for BAT collagen. These results show that FSC is less resistant to high temperature than BAT collagen. Copyright © 2017 Elsevier B.V. All rights reserved.

  7. High-temperature absorbed dose measurements in the megagray range

    International Nuclear Information System (INIS)

    Balian, P.; Ardonceau, J.; Zuppiroli, L.

    1988-01-01

    Organic conductors of the tetraselenotetracene family have been tested as ''high-temperature'' absorbed dose dosimeters. They were heated up to 120 0 C and irradiated at this temperature with 1-MeV electrons in order to simulate, in a short time, a much longer γ-ray irradiation. The electric resistance increase of the crystal can be considered a good measurement of the absorbed dose in the range 10 6 Gy to a few 10 8 Gy and presumably one order of magnitude more. This dosimeter also permits on-line (in-situ) measurements of the absorbed dose without removing the sensor from the irradiation site. The respective advantages of organic and inorganic dosimeters at these temperature and dose ranges are also discussed. In this connection, we outline new, but negative, results concerning the possible use of silica as a high-temperature, high-dose dosimeter. (author)

  8. 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

  9. Irradiation Creep of Ferritic-Martensitic Steels EP-450, EP-823 and EI-852 Irradiated in the BN-350 Reactor over Wide Ranges of Irradiation Temperature and Dose

    International Nuclear Information System (INIS)

    Porollo, S.I.; Konobeev, Y.V.; Ivanov, A.A.; Shulepin, S.V.; Garner, F.

    2007-01-01

    Full text of publication follows: Ferritic/martensitic (F/M) steels appear to be the most promising materials for advanced nuclear systems, especially for fusion reactors. Their main advantages are higher resistance to swelling and lower irradiation creep rate as has been repeatedly demonstrated in examinations of these materials after irradiation. Nevertheless, available experimental data on irradiation resistance of F/M steels are insufficient, with the greatest deficiency of data for high doses and for both low and high irradiation temperatures. From the very beginning of operation the BN-350 fast reactor has been used for irradiation of specimens of structural materials, including F/M steels. The most unique feature of BN-350 was its low inlet sodium temperature, allowing irradiation at temperatures over a very wide range of temperatures compared with the range in other fast reactors. In this paper data are presented on swelling and irradiation creep of three Russian F/M steels EP-450, EP-823 and EI-852, irradiated in experimental assemblies of the BN-350 reactor at temperatures in the range of 305-700 deg. C to doses ranging from 20 to 89 dpa. The investigation was performed using gas-pressurized creep tubes with hoop stresses in the range of 0 - 294 MPa. (authors)

  10. The materials programme for the high-temperature gas-cooled reactor in the Federal Republic of Germany: Status of the development of high-temperature materials, integrity concept, and design codes

    International Nuclear Information System (INIS)

    Nickel, H.; Bodmann, E.; Seehafer, H.J.

    1990-01-01

    During the last 15 years, the research and development of materials for high temperature gas-cooled reactor (HTGR) applications in the Federal Republic of Germany have been concentrated on the qualification of high-temperature structural alloys. Such materials are required for heat exchanger components of advanced HTGRs supplying nuclear process heat in the temperature range between 750 deg. and 950 deg. C. The suitability of the candidate alloys for service in the HTGR has been established, and continuing research is aimed at verification of the integrity of components over the envisaged service lifetimes. The special features of the HTGR which provide a high degree of safety are the use of ceramics for the core construction and the low power density of the core. The reactor integrity concept which has been developed is based on these two characteristics. Previously, technical guidelines and design codes for nuclear plants were tailored exclusively to light water reactor systems. An extensive research project was therefore initiated which led to the formulation of the basic principles on which a high temperature design code can be based. (author)

  11. Tribological behavior and self-healing functionality of TiNbCN-Ag coatings in wide temperature range

    Energy Technology Data Exchange (ETDEWEB)

    Bondarev, A.V., E-mail: abondarev88@gmail.com; Kiryukhantsev-Korneev, Ph.V.; Levashov, E.A.; Shtansky, D.V., E-mail: shtansky@shs.misis.ru

    2017-02-28

    Highlights: • TiNbCN–Ag coatings for wide temperature range tribological applications. • Alloying with Nb and Ag improve tribological properties and oxidation resistance. • Ag-rich TiNbCN coatings show friction coefficient below 0.45 in range of 25–700 °C. • Ag-doped coatings show active oxidation protection and self-healing functionality. - Abstract: Ag- and Nb-doped TiCN coatings with about 2 at.% of Nb and Ag contents varied between 4.0 and 15.1 at.% were designed as promising materials for tribological applications in a wide temperature range. We report on the structure, mechanical, and tribological properties of TiNbCN-Ag coatings fabricated by simultaneous co-sputtering of TiC{sub 0.5} + 10%Nb{sub 2}C and Ag targets in comparison with those of Ag-free coating. The tribological characteristics were evaluated during constant-temperature tests both at room temperature and 300 °C, as well as during dynamic temperature ramp tests in the range of 25–700 °C. The coating structure and elemental composition were studied by means of X-ray diffraction, scanning and transmission electron microscopy, and glow discharge optical emission spectroscopy. The coating microstructures and elemental compositions inside wear tracks, as well as the wear products, were examined by scanning electron microscopy, energy-dispersive spectroscopy, and Raman spectroscopy. We demonstrate that simultaneous alloying with Nb and Ag permits to overcome the main drawbacks of TiCN coatings such as their relatively high values of friction coefficient at elevated temperatures and low oxidation resistance. It is shown that a relatively high amount of Ag (15 at.%) is required to provide enhanced tribological behavior in a wide temperature range of 25–700 °C. In addition, the prepared Ag-doped coatings demonstrated active oxidation protection and self-healing functionality due to the segregation of Ag metallic particles in damage areas such as cracks, pin-holes, or oxidation sites.

  12. 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.

  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. High-entropy alloys as high-temperature thermoelectric materials

    Energy Technology Data Exchange (ETDEWEB)

    Shafeie, Samrand [Surface and Microstructure Engineering Group, Materials and Manufacturing Technology, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Guo, Sheng, E-mail: sheng.guo@chalmers.se [Surface and Microstructure Engineering Group, Materials and Manufacturing Technology, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Hu, Qiang [Institute of Applied Physics, Jiangxi Academy of Sciences, Nanchang 330029 (China); Fahlquist, Henrik [Bruker AXS Nordic AB, 17067 Solna (Sweden); Erhart, Paul [Department of Applied Physics, Chalmers University of Technology, SE-41296 Gothenburg (Sweden); Palmqvist, Anders, E-mail: anders.palmqvist@chalmers.se [Department of Chemistry and Chemical Engineering, Chalmers University of Technology, SE-41296 Gothenburg (Sweden)

    2015-11-14

    Thermoelectric (TE) generators that efficiently recycle a large portion of waste heat will be an important complementary energy technology in the future. While many efficient TE materials exist in the lower temperature region, few are efficient at high temperatures. Here, we present the high temperature properties of high-entropy alloys (HEAs), as a potential new class of high temperature TE materials. We show that their TE properties can be controlled significantly by changing the valence electron concentration (VEC) of the system with appropriate substitutional elements. Both the electrical and thermal transport properties in this system were found to decrease with a lower VEC number. Overall, the large microstructural complexity and lower average VEC in these types of alloys can potentially be used to lower both the total and the lattice thermal conductivity. These findings highlight the possibility to exploit HEAs as a new class of future high temperature TE materials.

  15. Materials Science of High-Temperature Superconducting Coated Conductor Materials

    National Research Council Canada - National Science Library

    Beasley, M. R

    2007-01-01

    This program was broadly focused on the materials science of high temperature superconducting coated conductors, which are of potential interest for application in electric power systems of interest to the Air Force...

  16. Corrosion assessment of refractory materials for high temperature waste vitrification

    International Nuclear Information System (INIS)

    Marra, J.C.; Congdon, J.W.; Kielpinski, A.L.

    1995-01-01

    A variety of vitrification technologies are being evaluated to immobilize radioactive and hazardous wastes following years of nuclear materials production throughout the Department of Energy (DOE) complex. The compositions and physical forms of these wastes are diverse ranging from inorganic sludges to organic liquids to heterogeneous debris. Melt and off-gas products can be very corrosive at the high temperatures required to melt many of these waste streams. Ensuring material durability is required to develop viable treatment processes. Corrosion testing of materials in some of the anticipated severe environments is an important aspect of the materials identification and selection process. Corrosion coupon tests on typical materials used in Joule heated melters were completed using glass compositions with high salt contents. The presence of chloride in the melts caused the most severe attack. In the metal alloys, oxidation was the predominant corrosion mechanism, while in the tested refractory material enhanced dissolution of the refractory into the glass was observed. Corrosion testing of numerous different refractory materials was performed in a plasma vitrification system using a surrogate heterogeneous debris waste. Extensive corrosion was observed in all tested materials

  17. 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.

  18. 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...

  19. Tribological behavior and self-healing functionality of TiNbCN-Ag coatings in wide temperature range

    Science.gov (United States)

    Bondarev, A. V.; Kiryukhantsev-Korneev, Ph. V.; Levashov, E. A.; Shtansky, D. V.

    2017-02-01

    Ag- and Nb-doped TiCN coatings with about 2 at.% of Nb and Ag contents varied between 4.0 and 15.1 at.% were designed as promising materials for tribological applications in a wide temperature range. We report on the structure, mechanical, and tribological properties of TiNbCN-Ag coatings fabricated by simultaneous co-sputtering of TiC0.5 + 10%Nb2C and Ag targets in comparison with those of Ag-free coating. The tribological characteristics were evaluated during constant-temperature tests both at room temperature and 300 °C, as well as during dynamic temperature ramp tests in the range of 25-700 °C. The coating structure and elemental composition were studied by means of X-ray diffraction, scanning and transmission electron microscopy, and glow discharge optical emission spectroscopy. The coating microstructures and elemental compositions inside wear tracks, as well as the wear products, were examined by scanning electron microscopy, energy-dispersive spectroscopy, and Raman spectroscopy. We demonstrate that simultaneous alloying with Nb and Ag permits to overcome the main drawbacks of TiCN coatings such as their relatively high values of friction coefficient at elevated temperatures and low oxidation resistance. It is shown that a relatively high amount of Ag (15 at.%) is required to provide enhanced tribological behavior in a wide temperature range of 25-700 °C. In addition, the prepared Ag-doped coatings demonstrated active oxidation protection and self-healing functionality due to the segregation of Ag metallic particles in damage areas such as cracks, pin-holes, or oxidation sites.

  20. 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.

  1. Methanol adsorption by amorphous silica alumina in the critical temperature range

    NARCIS (Netherlands)

    Kuczynski, M.; van Ooteghem, A.; Westerterp, K.R.

    1986-01-01

    The methanol adsorption capacity of an amorphous silica-alumina was measured using an equilibrium technique. The experimental temperature range was of 140 to 260°C and the pure methanol pressure range was 0.1 to 1.2 MPa. A multilayer adsorption was found, also for temperatures above the critical

  2. 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.

  3. Thermodynamic parameters of bonds in glassy materials from viscosity-temperature relationships

    International Nuclear Information System (INIS)

    Ojovan, Michael I; Travis, Karl P; Hand, Russell J

    2007-01-01

    Doremus's model of viscosity assumes that viscous flow in amorphous materials is mediated by broken bonds (configurons). The resulting equation contains four coefficients, which are directly related to the entropies and enthalpies of formation and motion of the configurons. Thus by fitting this viscosity equation to experimental viscosity data these enthalpy and entropy terms can be obtained. The non-linear nature of the equation obtained means that the fitting process is non-trivial. A genetic algorithm based approach has been developed to fit the equation to experimental viscosity data for a number of glassy materials, including SiO 2 , GeO 2 , B 2 O 3 , anorthite, diopside, xNa 2 O-(1-x)SiO 2 , xPbO-(1-x)SiO 2 , soda-lime-silica glasses, salol, and α-phenyl-o-cresol. Excellent fits of the equation to the viscosity data were obtained over the entire temperature range. The fitting parameters were used to quantitatively determine the enthalpies and entropies of formation and motion of configurons in the analysed systems and the activation energies for flow at high and low temperatures as well as fragility ratios using the Doremus criterion for fragility. A direct anti-correlation between fragility ratio and configuron percolation threshold, which determines the glass transition temperature in the analysed materials, was found

  4. Efficient Space Hardy Thermoelectric Materials with Broad Temperature Range, Phase I

    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...

  5. Installation for fatigue testing of materials at cryogenic temperatures

    International Nuclear Information System (INIS)

    Abushenkov, I.D.; Chernetskij, V.K.; Il'ichev, V.Ya.

    1986-01-01

    A new installation for mechanical fatigue tests of structural material samples is described, in which the possibility to conduct tests in the range of lower temperatures (4.2-300 K) is ensured. The installation permits to carry out fatigue tests using the method of axial loading of annular (up to 6 mm in diameter) and plane (up to 12 mm wide) samples during symmetric, asymmetric and pulsing loading cycles. It is shown that the installation suggested has quite extended operation possibilities and, coincidentally, it is characterized by design simplicity, compactness, comparatively low metal consumption and maintenance convenience

  6. Efficient Space Hardy Thermoelectric Materials with Broad Temperature Range, Phase II

    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...

  7. High temperature fracture of ceramic materials

    International Nuclear Information System (INIS)

    Wiederhorn, S.M.

    1979-01-01

    A review is presented of fracture mechanisms and methods of lifetime prediction in ceramic materials. Techniques of lifetime prediction are based on the science of fracture mechanics. Application of these techniques to structural ceramics is limited by our incomplete understanding of fracture mechanisms in these materials, and by the occurrence of flaw generation in these materials at elevated temperatures. Research on flaw generation and fracture mechanisms is recommended as a way of improving the reliability of structural ceramics

  8. Glassy aerosols with a range of compositions nucleate ice heterogeneously at cirrus temperatures

    Directory of Open Access Journals (Sweden)

    T. W. Wilson

    2012-09-01

    Full Text Available Atmospheric secondary organic aerosol (SOA is likely to exist in a semi-solid or glassy state, particularly at low temperatures and humidities. Previously, it has been shown that glassy aqueous citric acid aerosol is able to nucleate ice heterogeneously under conditions relevant to cirrus in the tropical tropopause layer (TTL. In this study we test if glassy aerosol distributions with a range of chemical compositions heterogeneously nucleate ice under cirrus conditions. Three single component aqueous solution aerosols (raffinose, 4-hydroxy-3-methoxy-DL-mandelic acid (HMMA and levoglucosan and one multi component aqueous solution aerosol (raffinose mixed with five dicarboxylic acids and ammonium sulphate were studied in both the liquid and glassy states at a large cloud simulation chamber. The investigated organic compounds have similar functionality to oxidised organic material found in atmospheric aerosol and have estimated temperature/humidity induced glass transition thresholds that fall within the range predicted for atmospheric SOA. A small fraction of aerosol particles of all compositions were found to nucleate ice heterogeneously in the deposition mode at temperatures relevant to the TTL (<200 K. Raffinose and HMMA, which form glasses at higher temperatures, nucleated ice heterogeneously at temperatures as high as 214.6 and 218.5 K respectively. We present the calculated ice active surface site density, ns, of the aerosols tested here and also of glassy citric acid aerosol as a function of relative humidity with respect to ice (RHi. We also propose a parameterisation which can be used to estimate heterogeneous ice nucleation by glassy aerosol for use in cirrus cloud models up to ~220 K. Finally, we show that heterogeneous nucleation by glassy aerosol may compete with ice nucleation on mineral dust particles in mid-latitudes cirrus.

  9. 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.

  10. Semiconductor resistance thermometer for the temperature range 300-0.3 K

    International Nuclear Information System (INIS)

    Zinov'eva, K.N.; Zarubin, L.I.; Nemish, I.Yu.; Vorobkalo, F.M.; Boldarev, S.T.; AN Ukrainskoj SSR, Kiev. Inst. Poluprovodnikov)

    1979-01-01

    Thermometric characteristics of semiconductor resistor thermometers for the temperature range from 300 to 0.3 K and from 77 to 0.3 K are given. Temperature dependence of thermometer resistances in the 300-1.3 K range was measured in cryostats with pumping-out of N 2 , H 2 and 4 He. For measurements below 1.3 K use was made of a 3 H- 4 He dissolving cryostat. The accuracy of measuring temperatures in the 1.3-0.3 K range is not below +-0.003 K, the error in determining thermometer resistances does not exceed 1%. The analysis of obtained thermometric characteristics of several series of semiconductor resistance thermometers showed that observed insignificant spread of resistances of thermometers in one series and identity of characteristics allows them to be used without preliminary calibration for relatively coarse measurements in the range from 3O0 to 0.3 K. Besides, it has been found that in the 4.2-0.3 K range the thermometric characteristics represent a straight line in the lgR-Tsup(-n) coordinates, where R is the thermometer resistance, T is the temperature and n=0.5. Thus, the thermometers of the same series can be calibrated only in 2 or 3 reference point measurements

  11. Outgassing tests on graphites in temperature range 100-1600 degrees C

    International Nuclear Information System (INIS)

    Alessandrini, C.; Apicella, M.L.; Verdini, L.

    1993-01-01

    Graphite is a an interesting material for plasma-facing components in fusion experiments, mainly because of its low atomic number and excellent thermal properties. Nevertheless, it contains a large amount of gaseous impurities, which can be released by plasma-surface interactions and affect the purity of the deuterium-tritium plasma. To investigate the outgassing behaviour of graphites, CFC's and doped C composites, a facility was set up to perform outgassing tests on samples, as a function of temperature in the range between 100 and 1600 degrees C. The experimental apparatus, designed to work in UHV conditions, allows outgassing measurements by a quadrupole mass spectrometer (1-200 AMU) using two different methods. The test facility, the quadrupole calibration and preliminary quantitative outgassing measurements on SEP CARB N112 samples are described

  12. 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.

  13. Studies on preparation and adaptive thermal control performance of novel PTC (positive temperature coefficient) materials with controllable Curie temperatures

    International Nuclear Information System (INIS)

    Cheng, Wen-long; Yuan, Shuai; Song, Jia-liang

    2014-01-01

    PTC (positive temperature coefficient) material is a kind of thermo-sensitive material. In this study, a series of novel PTC materials adapted to thermal control of electron devices are prepared. By adding different low-melting-point blend matrixes into GP (graphite powder)/LDPE (low density polyethylene) composite, the Curie temperatures are adjusted to 9 °C, 25 °C, 34 °C and 41 °C, and the resistance–temperature coefficients are enhanced to 1.57/°C–2.15/°C. These PTC materials remain solid in the temperature region of PTC effect, which makes it possible to be used as heating element to achieve adaptive temperature control. In addition, the adaptive thermal control performances of this kind of materials are investigated both experimentally and theoretically. The result shows that the adaptive effect becomes more significant while the resistance–temperature coefficient increases. A critical heating power defined as the initial heating power which makes the equilibrium temperature reach terminal temperature is presented. The adaptive temperature control will be effective only if the initial power is below this value. The critical heating power is determined by the Curie temperature and resistance–temperature coefficient of PTC materials, and a higher Curie temperature or resistance–temperature coefficient will lead to a larger critical heating power. - Highlights: • A series of novel PTC (positive temperature coefficient) materials were prepared. • The Curie point of PTC material can be adjusted by choosing different blend matrixes. • The resistance–temperature coefficient of PTC materials is enhanced to 2.15/°C. • The material has good adaptive temperature control ability with no auxiliary method. • A mathematical model is established to analyze the performance and applicability

  14. Self-weldability of various materials in high temperature sodium

    International Nuclear Information System (INIS)

    Mizobuchi, Syotaro; Kano, Shigeki; Nakayama, Kohichi; Atsumo, Hideo

    1980-01-01

    Self-Weldability of Various Materials in High Temperature Sodium. The self-welding behavior of various materials was evaluated by measuring the tensile breakaway force of the specimen which had been self-welded in high temperature sodium. Experiments were carried out to investigate the influence of the sodium temperature and the contact stress on the self-welding behavior. The results obtained are as follows: (1) The self-welding behavior in sodium was recognized to initiate by the diffusion of the principal element through the real contact area. (2) Remarkable self-welding behavior was observed for SUS 316 material at 650 0 C, and for 2 1/4Cr-1Mo steel at a sodium temperature of 600 0 C. The self-welding force acting on the real contact area corresponds to the tensile strength of each material. (3) Hard chrome plating or hardfacing material showed good self-weld resistance, but the different combinations of SUS 316 with either of these materials were observed to easily cause self-welding. (4) The self-weldability of Cr 3 C 2 /Ni-Cr material varied with the preparing methods, especially, with the distribution of the binder composition contained in this material. (5) A derived equation was proposed to evaluate the self-welding force. It was found that the measured breakaway force was relatively equal to the self-welding force derived from this equation. (author)

  15. Green's function method with consideration of temperature dependent material properties for fatigue monitoring of nuclear power plants

    International Nuclear Information System (INIS)

    Koo, Gyeong-Hoi; Kwon, Jong-Jooh; Kim, Wanjae

    2009-01-01

    In this paper, a method to consider temperature dependent material properties when using the Green's function method is proposed by using a numerical weight function approach. This is verified by using detailed finite element analyses for a pressurizer spray nozzle with various assumed thermal transient load cases. From the results, it is found that the temperature dependent material properties can significantly affect the maximum peak stresses and the proposed method can resolve this problem with the weight function approach. Finally, it is concluded that the temperature dependency of the material properties affects the maximum stress ranges for a fatigue evaluation. Therefore, it is necessary to consider this effect to monitor fatigue damage when using a Green's function method for the real operating conditions in a nuclear power plant

  16. Differential scanning calorimetry (DSC) and temperature-modulated DSC study of three mouthguard materials.

    Science.gov (United States)

    Meng, Frank H; Schricker, Scott R; Brantley, William A; Mendel, Deborah A; Rashid, Robert G; Fields, Henry W; Vig, Katherine W L; Alapati, Satish B

    2007-12-01

    Employ differential scanning calorimetry (DSC) and temperature-modulated DSC (TMDSC) to investigate thermal transformations in three mouthguard materials and provide insight into their previously investigated energy absorption. Samples (13-21mg) were obtained from (a) conventional ethylene vinyl acetate (EVA), (b) Pro-form, another EVA polymer, and (c) PolyShok, an EVA polymer containing polyurethane. Conventional DSC (n=5) was first performed from -80 to 150 degrees C at a heating rate of 10 degrees C/min to determine the temperature range for structural transformations. Subsequently, TMDSC (n=5) was performed from -20 to 150 degrees C at a heating rate of 1 degrees C/min. Onset and peak temperatures were compared using ANOVA and the Tukey-Kramer HSD test. Other samples were coated with a gold-palladium film and examined with an SEM. DSC and TMDSC curves were similar for both conventional EVA and Pro-form, showing two endothermic peaks suggestive of melting processes, with crystallization after the higher-temperature peak. Evidence for crystallization and the second endothermic peak were much less prominent for PolyShok, which had no peaks associated with the polyurethane constituent. The onset of the lower-temperature endothermic transformation is near body temperature. No glass transitions were observed in the materials. SEM examination revealed different surface morphology and possible cushioning effect for PolyShok, compared to Pro-form and EVA. The difference in thermal behavior for PolyShok is tentatively attributed to disruption of EVA crystal formation, which may contribute to its superior impact resistance. The lower-temperature endothermic peak suggests that impact testing of these materials should be performed at 37 degrees C.

  17. Determination of temperature dependency of material parameters for lead-free alkali niobate piezoceramics by the inverse method

    Directory of Open Access Journals (Sweden)

    K. Ogo

    2016-06-01

    Full Text Available Sodium potassium niobate (NKN piezoceramics have been paid much attention as lead-free piezoelectric materials in high temperature devices because of their high Curie temperature. The temperature dependency of their material parameters, however, has not been determined in detail up to now. For this purpose, we exploit the so-called Inverse Method denoting a simulation-based characterization approach. Compared with other characterization methods, the Inverse Method requires only one sample shape of the piezoceramic material and has further decisive advantages. The identification of material parameters showed that NKN is mechanically softer in shear direction compared with lead zirconate titanate (PZT at room temperature. The temperature dependency of the material parameters of NKN was evaluated in the temperature range from 30 °C to 150 °C. As a result, we figured out that dielectric constants and piezoelectric constants show a monotonous and isotropic increment with increasing temperature. On the other hand, elastic stiffness constant c 44 E of NKN significantly decreased in contrast to other elastic stiffness constants. It could be revealed that the decrement of c 44 E is associated with an orthorhombic-tetragonal phase transition. Furthermore, ratio of elastic compliance constants s 44 E / s 33 E exhibited similar temperature dependent behavior to the ratio of piezoelectric constants d15/d33. It is suspected that mechanical softness in shear direction is one origin of the large piezoelectric shear mode of NKN. Our results show that NKN are suitable for high temperature devices, and that the Inverse Method should be a helpful approach to characterize material parameters under their practical operating conditions for NKN.

  18. High Temperature Materials Interim Data Qualification Report

    International Nuclear Information System (INIS)

    Lybeck, Nancy

    2010-01-01

    Projects for the very high temperature reactor (VHTR) Technology Development Office provide data in support of Nuclear Regulatory Commission licensing of the VHTR. Fuel and materials to be used in the reactor are tested and characterized to quantify performance in high temperature and high fluence environments. The VHTR program has established the NGNP Data Management and Analysis System (NDMAS) to ensure that VHTR data are qualified for use, stored in a readily accessible electronic form, and analyzed to extract useful results. This document focuses on the first NDMAS objective. It describes the High Temperature Materials characterization data stream, the processing of these data within NDMAS, and reports the interim FY2010 qualification status of the data. Data qualification activities within NDMAS for specific types of data are determined by the data qualification category assigned by the data generator. The High Temperature Materials data are being collected under NQA-1 guidelines, and will be qualified data. For NQA-1 qualified data, the qualification activities include: (1) capture testing, to confirm that the data stored within NDMAS are identical to the raw data supplied, (2) accuracy testing to confirm that the data are an accurate representation of the system or object being measured, and (3) documenting that the data were collected under an NQA-1 or equivalent Quality Assurance program. Currently, data from two test series within the High Temperature Materials data stream have been entered into the NDMAS vault: (1) Tensile Tests for Sm (i.e., Allowable Stress) Confirmatory Testing - 1,403,994 records have been inserted into the NDMAS database. Capture testing is in process. (2) Creep-Fatigue Testing to Support Determination of Creep-Fatigue Interaction Diagram - 918,854 records have been processed and inserted into the NDMAS database. Capture testing is in process.

  19. Regulation of Silk Material Structure by Temperature-Controlled Water Vapor Annealing

    Science.gov (United States)

    Hu, Xiao; Shmelev, Karen; Sun, Lin; Gil, Eun-Seok; Park, Sang-Hyug; Cebe, Peggy; Kaplan, David L.

    2011-01-01

    We present a simple and effective method to obtain refined control of the molecular structure of silk biomaterials through physical temperature-controlled water vapor annealing (TCWVA). The silk materials can be prepared with control of crystallinity, from a low content using conditions at 4°C (alpha-helix dominated silk I structure), to highest content of ~60% crystallinity at 100°C (beta-sheet dominated silk II structure). This new physical approach covers the range of structures previously reported to govern crystallization during the fabrication of silk materials, yet offers a simpler, green chemistry, approach with tight control of reproducibility. The transition kinetics, thermal, mechanical, and biodegradation properties of the silk films prepared at different temperatures were investigated and compared by Fourier transform infrared spectroscopy (FTIR), differential scanning calorimetry (DSC), uniaxial tensile studies, and enzymatic degradation studies. The results revealed that this new physical processing method accurately controls structure, in turn providing control of mechanical properties, thermal stability, enzyme degradation rate, and human mesenchymal stem cell interactions. The mechanistic basis for the control is through the temperature controlled regulation of water vapor, to control crystallization. Control of silk structure via TCWVA represents a significant improvement in the fabrication of silk-based biomaterials, where control of structure-property relationships is key to regulating material properties. This new approach to control crystallization also provides an entirely new green approach, avoiding common methods which use organic solvents (methanol, ethanol) or organic acids. The method described here for silk proteins would also be universal for many other structural proteins (and likely other biopolymers), where water controls chain interactions related to material properties. PMID:21425769

  20. Analysis and description of the long-term creep behaviour of high-temperature gas turbine materials

    International Nuclear Information System (INIS)

    Bartsch, H.

    1985-01-01

    On a series of standard high-temperature gas turbine materials, creep tests were accomplished with the aim to obtain improved data on the long-term creep behaviour. The tests were carried out in the range of the main application temperatures of the materials and in the range of low stresses and elongations similar to operation conditions. They lasted about 5000 to 16000 h at maximum. At all important temperatures additional annealing tests lasting up to about 10000 h were carried out for the determination of a material-induced structure contraction. Thermal tension tests were effected for the description of elastoplastic short-time behaviour. As typical selection of materials the nickel investment casting alloys IN-738 LC, IN-939 and Udimet 500 for industrial turbine blades, IN-100 for aviation turbine blades and IN-713 C for integrally cast wheels of exhaust gas turbochargers were investigated, and also the nickel forge alloy Inconel 718 for industrial and aviation turbine disks and Nimonic 101 for industrial turbine blades and finally the cobalt alloy FSC 414 for guide blades and heat accumulation segments of industrial gas turbines. The creep tests were started on long-period individual creep testing machines with high strain measuring accuracy and economically continued on long-period multispecimen creep testing machines with long duration of test. The test results of this mixed test method were first subjected to a conventional evaluation in logarithmic time yield and creep diagrams which besides creep strength curves provided creep stress limit curves down to 0.2% residual strain. (orig./MM) [de

  1. Temperature dependence of thermal expansion of cadmium sulfide in the temperature range 20 - 820 K

    International Nuclear Information System (INIS)

    Oskotskij, V.S.; Kobyakov, I.B.; Solodukhin, A.V.

    1980-01-01

    The linear thermal expansion of cadmium sulfide is measured perpendicularly (α 1 ) and parallelly (α 2 ) to the hexagonal axis in the temperature range from 20 to 820 K. Anisotropy is low at up to 80 K; rises at higher temperatures; at 3OO K α 1 /α 3 ratio is 1.8; at 820 K, 2.4. Heat expansion is negative at temperatures lower than 104.5 K(α 1 ) and 126.0 K(α 2 ). It achieves the minimum at 43.6 K (α 1 ) and 52.5K (α 3 ). The theory of heat expansion is plotted in the Debue, approximation and cadmium sulfide is considered as an isotope crystal with average elastic constants. Two parameters of the theory are determined by the position and value of the minimum of volumetric thermal expansion of the model isotope crystal. The theoretic curve agrees well with the experimental one at temperatures up to 160 K, i.e in the range of applicability of the Debue approximation and the isotropic model

  2. Finite temperature CPN-1 model and long range Neel order

    International Nuclear Information System (INIS)

    Ichinose, Ikuo; Yamamoto, Hisashi.

    1989-09-01

    We study in d space-dimensions the finite temperature behavior of long range Neel order (LRNO) in CP N-1 model as a low energy effective field theory of the antiferromagnetic Heisenberg model. For d≤1, or d≤2 at any nonzero temperature, LRNO disappears, in agreement with Mermin-Wagner-Coleman's theorem. For d=3 in the weak coupling region, LRNO exists below the critical temperature T N (Neel temperature). T N decreases as the interlayer coupling becomes relatively weak compared with that within Cu-O layers. (author)

  3. Lattice Parameter of Polycrystalline Diamond in the Low-Temperature Range

    International Nuclear Information System (INIS)

    Paszkowicz, W.; Piszora, P.; Lasocha, W.; Margiolaki, I.; Brunelli, M.; Fitch, A.

    2010-01-01

    The lattice parameter for polycrystalline diamond is determined as a function of temperature in the 4-300 K temperature range. In the range studied, the lattice parameter, expressed in angstrom units, of the studied sample increases according to the equation a = 3.566810(12) + 6.37(41) x 10 -14 T 4 (approximately, from 3.5668 to 3.5673 A). This increase is larger than that earlier reported for pure single crystals. The observed dependence and the resulting thermal expansion coefficient are discussed on the basis of literature data reported for diamond single crystals and polycrystals. (authors)

  4. High energy storage density over a broad temperature range in sodium bismuth titanate-based lead-free ceramics.

    Science.gov (United States)

    Yang, Haibo; Yan, Fei; Lin, Ying; Wang, Tong; Wang, Fen

    2017-08-18

    A series of (1-x)Bi 0.48 La 0.02 Na 0.48 Li 0.02 Ti 0.98 Zr 0.02 O 3 -xNa 0.73 Bi 0.09 NbO 3 ((1-x)LLBNTZ-xNBN) (x = 0-0.14) ceramics were designed and fabricated using the conventional solid-state sintering method. The phase structure, microstructure, dielectric, ferroelectric and energy storage properties of the ceramics were systematically investigated. The results indicate that the addition of Na 0.73 Bi 0.09 NbO 3 (NBN) could decrease the remnant polarization (P r ) and improve the temperature stability of dielectric constant obviously. The working temperature range satisfying TCC 150  °C  ≤±15% of this work spans over 400 °C with the compositions of x ≥ 0.06. The maximum energy storage density can be obtained for the sample with x = 0.10 at room temperature, with an energy storage density of 2.04 J/cm 3 at 178 kV/cm. In addition, the (1-x)LLBNTZ-xNBN ceramics exhibit excellent energy storage properties over a wide temperature range from room temperature to 90 °C. The values of energy storage density and energy storage efficiency is 0.91 J/cm 3 and 79.51%, respectively, for the 0.90LLBNTZ-0.10NBN ceramic at the condition of 100 kV/cm and 90 °C. It can be concluded that the (1-x)LLBNTZ-xNBN ceramics are promising lead-free candidate materials for energy storage devices over a broad temperature range.

  5. Thermodynamics of Quantum Gases for the Entire Range of Temperature

    Science.gov (United States)

    Biswas, Shyamal; Jana, Debnarayan

    2012-01-01

    We have analytically explored the thermodynamics of free Bose and Fermi gases for the entire range of temperature, and have extended the same for harmonically trapped cases. We have obtained approximate chemical potentials for the quantum gases in closed forms of temperature so that the thermodynamic properties of the quantum gases become…

  6. Constitutive behaviour of an as-cast AA7050 alloy in the sub-solidus temperature range

    International Nuclear Information System (INIS)

    Subroto, T A S; Miroux, A G; Eskin, D G; Katgerman, L

    2012-01-01

    Aluminum alloy 7050 is of interest for aerospace industries due to its superior mechanical properties. However, its inherent solidification behaviour may augment the accumulation of residual stresses due to uneven cooling conditions upon direct-chill (DC) casting. This can increase the propensity of cold cracking (CC), which is a potentially catastrophic phenomenon in casting ingots. To predict the outcome of the aluminum casting process, ALSIM software is utilised. This software has the capability to predict CC susceptibility during the casting process. However, at the moment, ALSIM lacks the information regarding material constitutive behaviour in the sub-solidus temperature range, which is considered important for studying CC phenomenon. At the moment, ALSIM only has a partial constitutive database for AA7050 and misses data, especially in the vicinity of non-equilibrium solidus (NES) point. The present work presents measurements of tensile constitutive parameters in the temperature range between 400 °C and NES, which is for this alloy defined as 465 °C. The mechanical behaviour is tested in a Gleeble 3800 thermo-mechanical simulator. Constitutive parameters such as stress-strain curves, strain-rate sensitivity and ductility of the alloy have been measured at different test temperatures. With these constitutive data, we expect to improve the accuracy of ALSIM simulations in terms of CC prediction, and gain more insight into the evolution of mechanical properties of AA7050 in the temperature nearby the NES.

  7. Modelling and experimental study of low temperature energy storage reactor using cementitious material

    International Nuclear Information System (INIS)

    Ndiaye, Khadim; Ginestet, Stéphane; Cyr, Martin

    2017-01-01

    Highlights: • Numerical study of a thermochemical reactor using a cementitious material for TES. • Development and test of an original prototype based on this original material. • Comparison of the experimental and numerical results. • Energy balance of the experimental setup (charging and discharging phases). - Abstract: Renewable energy storage is now essential to enhance the energy performance of buildings and to reduce their environmental impact. Most adsorbent materials are capable of storing heat, in a large range of temperature. Ettringite, the main product of the hydration of sulfoaluminate binders, has the advantage of high energy storage density at low temperature, around 60 °C. The objective of this study is, first, to predict the behaviour of the ettringite based material in a thermochemical reactor during the heat storage process, by heat storage modelling, and then to perform experimental validation by tests on a prototype. A model based on the energy and mass balance in the cementitious material was developed and simulated in MatLab software, and was able to predict the spatiotemporal behaviour of the storage system. This helped to build a thermochemical reactor prototype for heat storage tests in both the charging and discharging phases. Thus experimental tests validated the numerical model and served as proof of concept.

  8. Creep performance of oxide ceramic fiber materials at elevated temperature in air and in steam

    Science.gov (United States)

    Armani, Clinton J.

    Structural aerospace components that operate in severe conditions, such as extreme temperatures and detrimental environments, require structural materials that have superior long-term mechanical properties and that are thermochemically stable over a broad range of service temperatures and environments. Ceramic matrix composites (CMCs) capable of excellent mechanical performance in harsh environments are prime candidates for such applications. Oxide ceramic materials have been used as constituents in CMCs. However, recent studies have shown that high-temperature mechanical performance of oxide-oxide CMCs deteriorate in a steam-rich environment. The degradation of strength at elevated temperature in steam has been attributed to the environmentally assisted subcritical crack growth in the oxide fibers. Furthermore, oxide-oxide CMCs have shown significant increases in steady-state creep rates in steam. The present research investigated the effects of steam on the high-temperature creep and monotonic tension performance of several oxide ceramic materials. Experimental facilities were designed and configured, and experimental methods were developed to explore the influence of steam on the mechanical behaviors of ceramic fiber tows and of ceramic bulk materials under temperatures in the 1100--1300°C range. The effects of steam on creep behavior of Nextel(TM)610 and Nextel(TM)720 fiber tows were examined. Creep rates at elevated temperatures in air and in steam were obtained for both types of fibers. Relationships between creep rates and applied stresses were modeled and underlying creep mechanisms were identified. For both types of fiber tows, a creep life prediction analysis was performed using linear elastic fracture mechanics and a power-law crack velocity model. These results have not been previously reported and have critical design implications for CMC components operating in steam or near the recommended design limits. Predictions were assessed and validated via

  9. Materials for high temperature reactor vessels

    International Nuclear Information System (INIS)

    Buenaventura Pouyfaucon, A.

    2004-01-01

    Within the 5th Euraton Framework Programme, a big effort is being made to promote and consolidate the development of the High Temperature Reactor (HTR). Empresarios Agrupados is participating in this project and among others, also forms part of the HTR-M project Materials for HTRs. This paper summarises the work carried out by Empresarios Agrupados regarding the material selection of the HTR Reactor Pressure Vessel (RPV). The possible candidate materials and the most promising ones are discussed. Design aspects such as the RPV sensitive zones and material damage mechanisms are considered. Finally, the applicability of the existing design Codes and Standards for the design of the HTR RPV is also discussed. (Author)

  10. Structure and tribological properties of MoCN-Ag coatings in the temperature range of 25–700 °C

    Energy Technology Data Exchange (ETDEWEB)

    Shtansky, D.V., E-mail: shtansky@shs.misis.ru [National University of Science and Technology “MISIS”, Leninsky Prospect 4, Moscow (Russian Federation); Bondarev, A.V.; Kiryukhantsev-Korneev, Ph.V. [National University of Science and Technology “MISIS”, Leninsky Prospect 4, Moscow (Russian Federation); Rojas, T.C.; Godinho, V.; Fernández, A. [Instituto de Ciencia de Materiales de Sevilla CSIC-US, Avda. Américo Vespucio 49, 41092 Sevilla (Spain)

    2013-05-15

    The preparation of hard coatings with low friction coefficient over a wide temperature range is still a challenge for the tribological community. The development of new nanocomposite materials consisting of different metal-ceramic phases, each of which exhibiting self-lubricating characteristics at different temperatures, may help to solve this problem. We report on the structure and tribological properties of MoCN-Ag coatings deposited by magnetron co-sputtering of Mo and C (graphite) targets and simultaneous sputtering of an Ag target either in pure nitrogen or in a gaseous mixture of Ar + N{sub 2}. The structure and elemental composition of the coatings were studied by means of X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, Raman spectroscopy, and glow discharge optical emission spectroscopy. The tribological properties of the coatings against an Al{sub 2}O{sub 3} ball were investigated first at discrete temperatures of 25, 500, and 700 °C, and then during continuous heating in the temperature range of 25–700 °C. The coating structure and their respective wear tracks were also examined to elucidate their phase transformations during heat treatments. The lowest friction coefficients (<0.4) were observed in the temperature ranges of 25–100 °C and 400–700 °C and can be explained by the presence of a free amorphous carbon phase, which served as a lubricant at low temperatures, and by a positive role of silver and two phases forming at elevated temperatures, molybdenum oxide and silver molybdate, which provided lubrication above 400 °C. In the temperature range between 100 and 400 °C, the friction coefficient was relatively high. This problem is to be addressed in future works.

  11. Structure and tribological properties of MoCN-Ag coatings in the temperature range of 25–700 °C

    International Nuclear Information System (INIS)

    Shtansky, D.V.; Bondarev, A.V.; Kiryukhantsev-Korneev, Ph.V.; Rojas, T.C.; Godinho, V.; Fernández, A.

    2013-01-01

    The preparation of hard coatings with low friction coefficient over a wide temperature range is still a challenge for the tribological community. The development of new nanocomposite materials consisting of different metal-ceramic phases, each of which exhibiting self-lubricating characteristics at different temperatures, may help to solve this problem. We report on the structure and tribological properties of MoCN-Ag coatings deposited by magnetron co-sputtering of Mo and C (graphite) targets and simultaneous sputtering of an Ag target either in pure nitrogen or in a gaseous mixture of Ar + N 2 . The structure and elemental composition of the coatings were studied by means of X-ray diffraction, scanning and transmission electron microscopy, X-ray photoelectron spectroscopy, energy dispersive spectroscopy, Raman spectroscopy, and glow discharge optical emission spectroscopy. The tribological properties of the coatings against an Al 2 O 3 ball were investigated first at discrete temperatures of 25, 500, and 700 °C, and then during continuous heating in the temperature range of 25–700 °C. The coating structure and their respective wear tracks were also examined to elucidate their phase transformations during heat treatments. The lowest friction coefficients (<0.4) were observed in the temperature ranges of 25–100 °C and 400–700 °C and can be explained by the presence of a free amorphous carbon phase, which served as a lubricant at low temperatures, and by a positive role of silver and two phases forming at elevated temperatures, molybdenum oxide and silver molybdate, which provided lubrication above 400 °C. In the temperature range between 100 and 400 °C, the friction coefficient was relatively high. This problem is to be addressed in future works.

  12. 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.

  13. Temperature analysis of laser ignited metalized material using spectroscopic technique

    Science.gov (United States)

    Bassi, Ishaan; Sharma, Pallavi; Daipuriya, Ritu; Singh, Manpreet

    2018-05-01

    The temperature measurement of the laser ignited aluminized Nano energetic mixture using spectroscopy has a great scope in in analysing the material characteristic and combustion analysis. The spectroscopic analysis helps to do in depth study of combustion of materials which is difficult to do using standard pyrometric methods. Laser ignition was used because it consumes less energy as compared to electric ignition but ignited material dissipate the same energy as dissipated by electric ignition and also with the same impact. Here, the presented research is primarily focused on the temperature analysis of energetic material which comprises of explosive material mixed with nano-material and is ignited with the help of laser. Spectroscopy technique is used here to estimate the temperature during the ignition process. The Nano energetic mixture used in the research does not comprise of any material that is sensitive to high impact.

  14. 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.

  15. Temperature dependence of HU values for various water equivalent phantom materials

    International Nuclear Information System (INIS)

    Homolka, P.; Nowotny, R.; Gahleitner, A.

    2002-01-01

    The temperature dependence of water equivalent phantom materials used in radiotherapy and diagnostic imaging has been investigated. Samples of phantom materials based on epoxy resin, polyethylene, a polystyrene-polypropylene mixture and commercially available phantom materials (Solid Water TM , Gammex RMI and Plastic Water TM , Nuclear Associates) were scanned at temperatures from 15 to 40 deg. C and HU values determined. At a reference temperature of 20 deg. C materials optimized for CT applications give HU values close to zero while the commercial materials show an offset of 119.77 HU (Plastic Water) and 27.69 HU (Solid Water). Temperature dependence was lowest for epoxy-based materials (EPX-W: -0.23 HU deg. C -1 ; Solid Water: -0.25 HU deg. C -1 ) and highest for a polyethylene-based material (X0: -0.72 HU deg. C -1 ). A material based on a mixture of polystyrene and polypropylene (PSPP1: -0.27 HU deg. C -1 ) is comparable to epoxy-based materials and water (-0.29 HU deg. C -1 ). (author)

  16. Long-range correlations in rectal temperature fluctuations of healthy infants during maturation.

    Directory of Open Access Journals (Sweden)

    Georgette Stern

    Full Text Available BACKGROUND: Control of breathing, heart rate, and body temperature are interdependent in infants, where instabilities in thermoregulation can contribute to apneas or even life-threatening events. Identifying abnormalities in thermoregulation is particularly important in the first 6 months of life, where autonomic regulation undergoes critical development. Fluctuations in body temperature have been shown to be sensitive to maturational stage as well as system failure in critically ill patients. We thus aimed to investigate the existence of fractal-like long-range correlations, indicative of temperature control, in night time rectal temperature (T(rec patterns in maturing infants. METHODOLOGY/PRINCIPAL FINDINGS: We measured T(rec fluctuations in infants every 4 weeks from 4 to 20 weeks of age and before and after immunization. Long-range correlations in the temperature series were quantified by the correlation exponent, alpha using detrended fluctuation analysis. The effects of maturation, room temperature, and immunization on the strength of correlation were investigated. We found that T(rec fluctuations exhibit fractal long-range correlations with a mean (SD alpha of 1.51 (0.11, indicating that T(rec is regulated in a highly correlated and hence deterministic manner. A significant increase in alpha with age from 1.42 (0.07 at 4 weeks to 1.58 (0.04 at 20 weeks reflects a change in long-range correlation behavior with maturation towards a smoother and more deterministic temperature regulation, potentially due to the decrease in surface area to body weight ratio in the maturing infant. alpha was not associated with mean room temperature or influenced by immunization CONCLUSIONS: This study shows that the quantification of long-range correlations using alpha derived from detrended fluctuation analysis is an observer-independent tool which can distinguish developmental stages of night time T(rec pattern in young infants, reflective of maturation of

  17. Diatomite: A promising natural candidate as carrier material for low, middle and high temperature phase change material

    International Nuclear Information System (INIS)

    Qian, Tingting; Li, Jinhong; Min, Xin; Deng, Yong; Guan, Weimin; Ning, Lei

    2015-01-01

    Graphical abstract: Low-temperature PCMs are always the objects of prime investigations, however, the field of PCMs’ applications is not limited to low temperatures only. In the present study, three kinds of PCMs: polyethylene glycol (PEG), lithium nitrate, and sodium sulfate were respectively employed as the low-, middle- and high-temperature storage medium. A series of novel form-stable phase change materials (fs-PCMs) were tailor-made by blending diatomite and the three kinds of PCMs via a vacuum impregnation method or a facile mixing and sintering method. Various techniques were employed to characterize their structural and thermal properties. - Highlights: • Low-temperature PEG/diatomite was prepared. • Middle-temperature LiNO 3 /diatomite was prepared. • High-temperature Na 2 SO 4 /diatomite was prepared. - Abstract: Low-temperature PCMs are always the objects of prime investigations, however, the field of PCM’s application is not only limited to low temperatures. In this study, polyethylene glycol (PEG), lithium nitrate (LiNO 3 ), and sodium sulfate (Na 2 SO 4 ) were respectively employed as the low-, middle- and high-temperature storage medium. A series of novel form-stable phase change materials (fs-PCMs) were tailor-made by blending diatomite and the three PCMs via a vacuum impregnation method or a facile mixing and sintering method. Various techniques were employed to characterize their structural and thermal properties. The maximum loads of PEG, LiNO 3 , and Na 2 SO 4 in diatomite powder could respectively reach 58%, 60%, and 65%, while PCM melts during the solid–liquid phase transformation. SEM, XRD, and FT-IR results indicated that PCMs were well dispersed into diatomite pores and no chemical changes took place during the heating and cooling process. The prepared fs-PCMs were quite stable in terms of thermal and chemical manner even after a 200-cycle of melting and freezing. The resulting composite fs-PCMs were promising candidates to

  18. Thermotaxis of human sperm cells in extraordinarily shallow temperature gradients over a wide range.

    Directory of Open Access Journals (Sweden)

    Anat Bahat

    Full Text Available On the basis of the finding that capacitated (ready to fertilize rabbit and human spermatozoa swim towards warmer temperatures by directing their movement along a temperature gradient, sperm thermotaxis has been proposed to be one of the processes guiding these spermatozoa to the fertilization site. Although the molecular mechanism underlying sperm thermotaxis is gradually being revealed, basic questions related to this process are still open. Here, employing human spermatozoa, we addressed the questions of how wide the temperature range of thermotaxis is, whether this range includes an optimal temperature or whether spermatozoa generally prefer swimming towards warmer temperatures, whether or not they can sense and respond to descending temperature gradients, and what the minimal temperature gradient is to which they can thermotactically respond. We found that human spermatozoa can respond thermotactically within a wide temperature range (at least 29-41°C, that within this range they preferentially accumulate in warmer temperatures rather than at a single specific, preferred temperature, that they can respond to both ascending and descending temperature gradients, and that they can sense and thermotactically respond to temperature gradients as low as <0.014°C/mm. This temperature gradient is astonishingly low because it means that as a spermatozoon swims through its entire body length (46 µm it can sense and respond to a temperature difference of <0.0006°C. The significance of this surprisingly high temperature sensitivity is discussed.

  19. Restrained shrinkage experiments on coated particle fuel compacts in the temperature range 600-1200 deg C

    International Nuclear Information System (INIS)

    Blackstone, R.; Veringa, H.J.; Loelgen, R.

    1976-05-01

    Information on irradiation induced creep in reactor graphite and in fuel compact material is an essential ingredient in the design of any reactor core layout, because the creep plasticity of these materials diminishes the stresses which are built up in the fuel element during reactor operation. The restrained shrinkage method in which the shrinkage of a dumbbell shaped creep specimen is restrained by a graphite material which shows less irradiation shrinkage, offers a good possibility of performing a large series of tensile creep experiments in a limited irradiation volume. The irradiations, evaluations and the results of a series of restrained shrinkage experiments in which six different materials were tested, of which five were dummy coated particle compacts and one pure matrix material are described and discussed. These materials were irradiated in the High Flux Reactor of the Euratom Joint Research Centre in Petten/Netherlands. The irradiations were performed in three successive capsules at irradiation temperatures of 600 deg C, 900 deg C, 1050 deg C and 1200 deg C up to a neutron fluence of maximum 3x10 21 n.cm 2 (DNE). The post-irradiation examinations yielded plastic strains up to 2,3%, and values for the radiation creep coefficient were calculated, ranging from 4 to 8.10 -12 at 600 deg C and 8 to 30.10 -12 at 1200 deg C always given per dyn.cm -2 tensile stresses and per 10 20 n.cm -2 fluence units. Generally it was found that the creep behavior of these materials and the temperature dependence of the creep process could be compared with those for normal reactor graphites

  20. Certification of a second series of five hydrocarbon materials for the determination of equilibrium flashpoint (temperature ranges -10/sup 0/C to +5/sup 0/C and 80/sup 0/C to 135/sup 0/C)

    Energy Technology Data Exchange (ETDEWEB)

    Lewis, D J; Gonska, H; Karcher, W

    1984-01-01

    The closed cup flashpoints of five pure hydrocarbon materials (iso-octane, toluene, n-dodecane, n-tetradecane and n-hexadecane) have been determined by equilibrium methods in an interlaboratory exercise, involving twelve laboratories of the European Community member countries and one laboratory of the Commission of the European Communities. The methods used were based on IP303/74 (or ASTM D3278-73; Rapid Tester) and IP304/74 (Abel, Abel-Pensky, Pensky-Martens Cups) with extension to allow equilibrium conditions to be maintained outside the ranges of these methods. For each hydrocarbon material, the numbers of individual measurements accepted have been between 81 and 92. As a result, the closed cup flashpoints of these materials by an equilibrium method are certified at the following temperatures: CRM No. Hydrocarbon Equilibrium closed cup flashpoint 83 iso-octane -9.5 +- 0.5/sup 0/C 84 toluene +6.0 +- 0.5/sup 0/C 85 n-dodecane +81.0 +- 1.0/sup 0/C 86 n-tetradecane +108.0 +- 1.0/sup 0/C 87 n-hexadecane +133.5 +- 1.0/sup 0/C. This report describes the experimental details of the interlaboratory measurements and the certification procedure. The procedure required extensions to be made to methods IP303/74 and IP304/74 which are given in detail and recommendations are made for the improvement of these methods over the temperature range covered by the flashpoint reference materials.

  1. 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...... contact angle and cleanability. In addition to surface wettability with oil many other factors such as roughness and surface defects play an essential role in determining their cleanability....

  2. Theoretical study of energetic interactions between high temperature molten materials and a low temperature fluid

    International Nuclear Information System (INIS)

    Chen, S.H.H.

    1984-01-01

    Analytical models are developed to predict the hydrodynamical transients resulting from the energetic interactions between a high temperature molten material and a low temperature liquid coolant. Initially, the molten material at high temperature and pressure is separated from the low temperature fluid by a solid metal barrier. Upon contact between the molten material and solid barrier, thermal attack occurs eventually resulting in a loss of barrier integrity. Subsequently, the molten material is injected into the liquid pool resulting in energetic interactions. The analytical models integrate a wide variety of potentially mutually-interacting transport phenomena which dominate the transient process into a deterministic scheme to predict the hydrodynamic transient process into a deterministic scheme to predict the hydrodynamic transient process. The model calculations are compared with the existing experimental results to show its engineering accuracy and adequacy in predicting such energetic interactions. Two models are formulated to bracket the transport of molten material to the rupture site for the reactor system. The stratified model minimized the rate of transport of material to the break location while the dispersed model maximized such transport. These two models are applied to a reference pressure tube reactor to evaluate the pressure transients and the potential structural damages as a result of a postulated severe primary coolant blockage in a power channel

  3. 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

  4. Mechanical properties of silicone based composites as a temperature insensitive ballistic backing material for quantifying back face deformation.

    Science.gov (United States)

    Edwards, Tara D; Bain, Erich D; Cole, Shawn T; Freeney, Reygan M; Halls, Virginia A; Ivancik, Juliana; Lenhart, Joseph L; Napadensky, Eugene; Yu, Jian H; Zheng, James Q; Mrozek, Randy A

    2018-04-01

    This paper describes a new witness material for quantifying the back face deformation (BFD) resulting from high rate impact of ballistic protective equipment. Accurate BFD quantification is critical for the assessment and certification of personal protective equipment, such as body armor and helmets, and ballistic evaluation. A common witness material is ballistic clay, specifically, Roma Plastilina No. 1 (RP1). RP1 must be heated to nearly 38°C to pass calibration, and used within a limited time frame to remain in calibration. RP1 also exhibits lot-to-lot variability and is sensitive to time, temperature, and handling procedures, which limits the BFD accuracy and reproducibility. A new silicone composite backing material (SCBM) was developed and tested side-by-side with heated RP1 using quasi-static indentation and compression, low velocity impact, spherical projectile penetration, and both soft and hard armor ballistic BFD measurements to compare their response over a broad range of strain rates and temperatures. The results demonstrate that SCBM mimics the heated RP1 response at room temperature and exhibits minimal temperature sensitivity. With additional optimization of the composition and processing, SCBM could be a drop-in replacement for RP1 that is used at room temperature during BFD quantification with minimal changes to the current RP1 handling protocols and infrastructure. It is anticipated that removing the heating requirement, and temperature-dependence, associated with RP1 will reduce test variability, simplify testing logistics, and enhance test range productivity. Published by Elsevier B.V.

  5. 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.

  6. High temperature structural ceramic materials manufactured by the CNTD process

    International Nuclear Information System (INIS)

    Stiglich, J.J. Jr.; Bhat, D.G.; Holzl, R.A.

    1980-01-01

    Controlled Nucleation Thermochemical Deposition (CNTD) has emerged from classical chemical deposition (CVD) technology. This paper describes the techniques of thermochemical grain refinement. The effects of such refinement on mechanical properties of materials at room temperature and at elevated temperatures are outlined. Emphasis is given to high temperature structural ceramic materials such as SiC, Si 3 N 4 , AlN, and TiB 2 and ZrB 2 . An example of grain refinement accompanied by improvements in mechanical properties is SiC. Grain sizes of 500 to 1000 A have been observed in CNTD SiC with room temperature MOR of 1380 to 2070 MPa (4 pt bending) and MOR of 3450 to 4140 MPa (4 pt bending) at 1350 0 C. Various applications of these materials to the solution of high temperature structural problems are described. (author)

  7. 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

  8. A material model for aluminium sheet forming at elevated temperatures

    NARCIS (Netherlands)

    van den Boogaard, Antonius H.; Werkhoven, R.J.; Bolt, P.J.

    2001-01-01

    In order to accurately simulate the deep drawing or stretching of aluminum sheet at elevated temperatures, a model is required that incorporates the temperature and strain-rate dependency of the material. In this paper two models are compared: a phenomenological material model in which the

  9. High temperature superconductor bulk materials. Fundamentals - processing - properties control - application aspects

    International Nuclear Information System (INIS)

    Krabbes, G.; Fuchs, G.; Canders, W.R.; May, H.; Palka, R.

    2006-01-01

    This book presents all the features of bulk high temperature superconducting materials. Starting from physical and chemical fundamentals, the authors move on to portray methods and problems of materials processing, thoroughly working out the characteristic properties of bulk superconductors in contrast to long conductors and films. The authors provide a wide range of specific materials characteristics with respect to the latest developments and future applications guiding from fundamentals to practical engineering examples. This book contains the following chapters: 1. Fundamentals 2. Growth and melt processing of YBCO 3. Pinning-relevant defects in bulk YBCO 4. Properties of bulk YBCO 5. Trapped fields 6. Improved YBCO based bulk superconductors and functional elements 7. Alternative systems 8. Peak effect 9. Very high trapped fields in YBCO permanent magnets 10. Engineering aspects: Field distribution in bulk HTSC 11. Inherently stable superconducting magnetic bearings 12. Application of bulk HTSCs in electromagnetic energy converters 13. Applications in magnet technologies and power supplies

  10. 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.

  11. 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...

  12. 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.

  13. High-temperature thermoelectric behavior of lead telluride

    Indian Academy of Sciences (India)

    Usefulness of a material in thermoelectric devices is temperature specific. The central problem in thermoelectric material research is the selection of materials with high figure-of-merit in the given temperature range of operation. It is of considerable interest to know the utility range of the material, which is decided by the ...

  14. Room temperature ferromagnetism in a phthalocyanine based carbon material

    International Nuclear Information System (INIS)

    Honda, Z.; Sato, K.; Sakai, M.; Fukuda, T.; Kamata, N.; Hagiwara, M.; Kida, T.

    2014-01-01

    We report on a simple method to fabricate a magnetic carbon material that contains nitrogen-coordinated transition metals and has a large magnetic moment. Highly chlorinated iron phthalocyanine was used as building blocks and potassium as a coupling reagent to uniformly disperse nitrogen-coordinated iron atoms on the phthalocyanine based carbon material. The iron phthalocyanine based carbon material exhibits ferromagnetic properties at room temperature and the ferromagnetic phase transition occurs at T c  = 490 ± 10 K. Transmission electron microscopy observation, X-ray diffraction analysis, and the temperature dependence of magnetization suggest that the phthalocyanine molecules form three-dimensional random networks in the iron phthalocyanine based carbon material

  15. Room temperature ferromagnetism in a phthalocyanine based carbon material

    Energy Technology Data Exchange (ETDEWEB)

    Honda, Z., E-mail: honda@fms.saitama-u.ac.jp; Sato, K.; Sakai, M.; Fukuda, T.; Kamata, N. [Graduate School of Science and Engineering, Saitama University, 255 Shimo-Okubo, Sakura-ku, Saitama 338-8570 (Japan); Hagiwara, M.; Kida, T. [KYOKUGEN (Center for Quantum Science and Technology under Extreme Conditions), Osaka University, 1-3 Machikaneyama, Toyonaka, Osaka 560-8531 (Japan)

    2014-02-07

    We report on a simple method to fabricate a magnetic carbon material that contains nitrogen-coordinated transition metals and has a large magnetic moment. Highly chlorinated iron phthalocyanine was used as building blocks and potassium as a coupling reagent to uniformly disperse nitrogen-coordinated iron atoms on the phthalocyanine based carbon material. The iron phthalocyanine based carbon material exhibits ferromagnetic properties at room temperature and the ferromagnetic phase transition occurs at T{sub c} = 490 ± 10 K. Transmission electron microscopy observation, X-ray diffraction analysis, and the temperature dependence of magnetization suggest that the phthalocyanine molecules form three-dimensional random networks in the iron phthalocyanine based carbon material.

  16. Calibration of a T-History calorimeter to measure enthalpy curves of phase change materials in the temperature range from 40 to 200 °C

    International Nuclear Information System (INIS)

    Rathgeber, Christoph; Schmit, Henri; Hennemann, Peter; Hiebler, Stefan

    2014-01-01

    Thermal energy storage using phase change materials (PCMs) provides high storage capacities in small temperature ranges. For the design of efficient latent heat storage, the enthalpy curve of a PCM has to be measured with high precision. Measurements are most commonly performed with differential scanning calorimetry (DSC). The T-History method, however, proved to be favourable for the characterization of typical PCMs due to large samples and a measuring procedure close to conditions found in applications. As T-History calorimeters are usually individual constructions, performing a careful calibration procedure is decisive to ensure optimal measuring accuracy. We report in this paper on the calibration of a T-History calorimeter with a working range from 40 to 200 °C that was designed and built at our institute. A three-part procedure, consisting of an indium calibration, a measurement of the specific heat of copper and measurements of three solid–liquid PCMs (stearic acid, dimethyl terephthalate and d-mannitol), was performed and an advanced procedure for the correction of enthalpy curves was developed. When comparing T-History enthalpy curves to literature data and DSC step measurements, good agreement within the uncertainty limits demanded by RAL testing specifications was obtained. Thus, our design of a T-History calorimeter together with the developed calibration procedure provides the measuring accuracy that is required to identify the most suitable PCM for a given application. In addition, the dependence of the enthalpy curve on the sample size can be analysed by comparing results obtained with T-History and DSC and the behaviour of the bulk material in real applications can be predicted. (paper)

  17. In-situ high temperature XRD of calcium phosphate biomaterial using DEHPA as the starting material

    International Nuclear Information System (INIS)

    Meor Yusoff Meor Sulaiman; Masliana Muslim

    2009-01-01

    A process to produce calcium phosphate biomaterial was done using an organic based phosphoric acid (DEHPA) as its starting material. The gel obtained from this reaction was used to study calcium phosphate transformation using in-situ XRD with temperature ranges from room temperature to 1300 degree C. The results obtained from this analysis show the following phase transformation: Gel β-Ca 2 P 2 O 7 β-TCP + HA α-TCP + HA, β-Ca 2 P 2 O 7 forms at 400 degree C and as we heat the sample at 1000 degree C peaks belonging to β- TCP and HA appears showing the transformation of the β-Ca 2 P 2 O 7 phase. When the sample is heated up further to 1200 degree C, β-TCP is transform into α-TCP. In the cold in-situ study, XRD analysis was performed on the sample from room temperature to -140 degree C. At room the XRD diffractogram shows the sample as an amorphous material and as the temperature was further lowered sharp peaks begins to form indicating that the material had becomes crystalline. The peaks were identified to be that calcium hydrogen phosphate (Ca(H 2 PO 4 ) 2 ) and this indicates that there is no hydroxyl group removal during the cooling process. The relative crystallinity values obtained for the different cooling temperatures show a slow exponential increase on the initial cooling of 0 to -100 degree C and at further cooling temperatures resulted fast and linear process. Also unlike the in-situ XRD analysis performs at high temperature no phase transformation occurred at this low temperature. (Author)

  18. Titanium carbide nanocube core induced interfacial growth of crystalline polypyrrole/polyvinyl alcohol lamellar shell for wide-temperature range supercapacitors

    Science.gov (United States)

    Weng, Yu-Ting; Pan, Hsiao-An; Wu, Nae-Lih; Chen, Geroge Zheng

    2015-01-01

    This is the first investigation on electrically conducting polymers-based supercapacitor electrodes over a wide temperature range, from -18 °C to 60 °C. A high-performance supercapacitor electrode material consisting of TiC nanocube core and conformal crystalline polypyrrole (PPy)/poly-vinyl-alcohol (PVA) lamellar shell has been synthesized by heterogeneous nucleation-induced interfacial crystallization. PPy is induced to crystallize on the negatively charged TiC nanocube surfaces via strong interfacial interactions. In this organic-inorganic hybrid nanocomposite, the long chain PVA enables enhanced cycle life due to improved mechanical properties, and the TiC nanocube not only contributes to electron conduction, but also dictates the PPy morphology/crystallinity for maximizing the charging-discharging performance. The crystalline PPy/PAV layer on the TiC nanocube offers unprecedented high capacity (>350 F g-1-PPy at 300 mV s-1 with ΔV = 1.6 V) and cycling stability in a temperature range from -18 °C to 60 °C. The presented hybrid-filler and interfacial crystallization strategies can be applied to the exploration of new-generation high-power conducting polymer-based supercapacitor materials.

  19. Mechanical properties of LMR structural materials at high temperature

    International Nuclear Information System (INIS)

    Kim, D. W.; Kuk, I. H.; Ryu, W. S. and others

    1999-03-01

    Austenitic stainless is used for the structural material of liquid metal reactor (LMR) because of good mechanical properties at high temperature. Stainless steel having more resistant to temperature by adding minor element has been developing for operating the LMR at higher temperature. Of many elements, nitrogen is a prospective element to modify type 316L(N) stainless steel because nitrogen is the most effective element for solid solution and because nitrogen retards the precipitation of carbide at grain boundary. Ti, Nb, and V are added to improve creep properties by stabilizing the carbides through forming MC carbide. Testing techniques of tensile, fatigue, creep, and creep-fatigue at high temperature are difficult. Moreover, testing times for creep and creep-fatigue tests are very long up to several tens of thousands hours because creep and creep-fatigue phenomena are time-dependent damage mechanism. So, it is hard to acquire the material data for designing LMR systems during a limited time. In addition, the integrity of LMR structural materials at the end of LMR life has to be predicted from the laboratory data tested during the short term because there is no data tested during 40 years. Therefore, the effect of elements on mechanical properties at high temperature was reviewed in this study and many methods to predict the long-term behaviors of structural materials by simulated modelling equation is shown in this report. (author). 32 refs., 9 tabs., 38 figs

  20. Ceramic matrix composites -- Advanced high-temperature structural materials

    International Nuclear Information System (INIS)

    Lowden, R.A.; Ferber, M.K.; DiPietro, S.G.

    1995-01-01

    This symposium on Ceramic Matrix Composites: Advanced High-Temperature Structural Materials was held at the 1994 MRS Fall Meeting in Boston, Massachusetts on November 28--December 2. The symposium was sponsored by the Department of Energy's Office of Industrial Technology's Continuous Fiber Ceramic Composites Program, the Air Force Office of Scientific Research, and NASA Lewis Research Center. Among the competing materials for advanced, high-temperature applications, ceramic matrix composites are leading candidates. The symposium was organized such that papers concerning constituents--fibers and matrices--were presented first, followed by composite processing, modeling of mechanical behavior, and thermomechanical testing. More stable reinforcements are necessary to enhance the performance and life of fiber-reinforced ceramic composites, and to ensure final acceptance of these materials for high-temperature applications. Encouraging results in the areas of polymer-derived SiC fibers and single crystal oxide filaments were given, suggesting composites with improved thermomechanical properties and stability will be realized in the near future. The significance of the fiber-matrix interface in the design and performance of these materials is evident. Numerous mechanical models to relate interface properties to composite behavior, and interpret test methods and data, were enthusiastically discussed. One issue of great concern for any advanced material for use in extreme environments is stability. This theme arose frequently throughout the symposium and was the topic of focus on the final day. Fifty nine papers have been processed separately for inclusion on the data base

  1. 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.

  2. Irradiation effect of the insulating materials for fusion superconducting magnets at cryogenic temperature

    Science.gov (United States)

    Kobayashi, Koji; Akiyama, Yoko; Nishijima, Shigehiro

    2017-09-01

    In ITER, superconducting magnets should be used in such severe environment as high fluence of fast neutron, cryogenic temperature and large electromagnetic forces. Insulating material is one of the most sensitive component to radiation. So radiation resistance on mechanical properties at cryogenic temperature are required for insulating material. The purpose of this study is to evaluate irradiation effect of insulating material at cryogenic temperature by gamma-ray irradiation. Firstly, glass fiber reinforced plastic (GFRP) and hybrid composite were prepared. After irradiation at room temperature (RT) or liquid nitrogen temperature (LNT, 77 K), interlaminar shear strength (ILSS) and glass-transition temperature (Tg) measurement were conducted. It was shown that insulating materials irradiated at room temperature were much degraded than those at cryogenic temperature.

  3. Development of materials for high temperature superconductor Josephson junctions

    International Nuclear Information System (INIS)

    Houlton, R.J.; Reagor, D.W.; Hawley, M.E.; Springer, K.N.; Jia, Q.X.; Mombourquette, C.B.; Garzon, F.H.; Wu, X.D.

    1994-01-01

    We have conducted a systematic optimization of deposition parameters for fabrication of multilayered oxide films to be used in the development of high temperature superconducting SNS Functions. These films were deposited by off-axis sputtering using a custom fabricated multi-gun planar magnetron system. Each material and the various combinations of materials were optimized for epitaxial lattice match, crystal quality, film uniformity, electrical properties, and surface microstructure. In addition to the standard procedures commonly used to sputter deposit epitaxial oxide films, a variety of insitu and exsitu procedures were used to produce high quality multilayer devices, including varying the nucleation temperature from the actual film growth temperature, location of the substrate during the deposition process, constant rotation of the substrate, and timing of the oxygen anneal. The unprocessed films and devices in process were characterized with Atomic Force Microscopy and Scanning Tunneling Microscopy as well as other common materials characterization techniques. Completed multilayer devices were patterned and packaged for electrical characterization. Relation between material properties and electrical characteristics is discussed

  4. Development of materials for high temperature superconductor Josephson junctions

    Energy Technology Data Exchange (ETDEWEB)

    Houlton, R.J.; Reagor, D.W.; Hawley, M.E.; Springer, K.N.; Jia, Q.X.; Mombourquette, C.B.; Garzon, F.H.; Wu, X.D.

    1994-10-01

    We have conducted a systematic optimization of deposition parameters for fabrication of multilayered oxide films to be used in the development of high temperature superconducting SNS Functions. These films were deposited by off-axis sputtering using a custom fabricated multi-gun planar magnetron system. Each material and the various combinations of materials were optimized for epitaxial lattice match, crystal quality, film uniformity, electrical properties, and surface microstructure. In addition to the standard procedures commonly used to sputter deposit epitaxial oxide films, a variety of insitu and exsitu procedures were used to produce high quality multilayer devices, including varying the nucleation temperature from the actual film growth temperature, location of the substrate during the deposition process, constant rotation of the substrate, and timing of the oxygen anneal. The unprocessed films and devices in process were characterized with Atomic Force Microscopy and Scanning Tunneling Microscopy as well as other common materials characterization techniques. Completed multilayer devices were patterned and packaged for electrical characterization. Relation between material properties and electrical characteristics is discussed

  5. Infrared Thermography Sensor for Temperature and Speed Measurement of Moving Material.

    Science.gov (United States)

    Usamentiaga, Rubén; García, Daniel Fernando

    2017-05-18

    Infrared thermography offers significant advantages in monitoring the temperature of objects over time, but crucial aspects need to be addressed. Movements between the infrared camera and the inspected material seriously affect the accuracy of the calculated temperature. These movements can be the consequence of solid objects that are moved, molten metal poured, material on a conveyor belt, or just vibrations. This work proposes a solution for monitoring the temperature of material in these scenarios. In this work both real movements and vibrations are treated equally, proposing a unified solution for both problems. The three key steps of the proposed procedure are image rectification, motion estimation and motion compensation. Image rectification calculates a front-parallel projection of the image that simplifies the estimation and compensation of the movement. Motion estimation describes the movement using a mathematical model, and estimates the coefficients using robust methods adapted to infrared images. Motion is finally compensated for in order to produce the correct temperature time history of the monitored material regardless of the movement. The result is a robust sensor for temperature of moving material that can also be used to measure the speed of the material. Different experiments are carried out to validate the proposed method in laboratory and real environments. Results show excellent performance.

  6. Low-temperature catalytic conversion of carbonaceous materials

    Directory of Open Access Journals (Sweden)

    Tabakaev Roman B.

    2015-01-01

    Full Text Available Laws of the rate of carbon conversion in steam atmosphere at a temperature in modes of the catalytic low-temperature treatment of peat, brown coal, semi-coke from peat and brown coal are obtained by experiments. Increasing of the rate of carbon conversion in temperature range up to 500 °C is achieved by using of catalysts. The possibility of using results is associated with the burners, a working zone of which is porous filling from carbonaceous particles.

  7. Non-destructive inspection approach using ultrasound to identify the material state for amorphous and semi-crystalline materials

    Science.gov (United States)

    Jost, Elliott; Jack, David; Moore, David

    2018-04-01

    At present, there are many methods to identify the temperature and phase of a material using invasive techniques. However, most current methods require physical contact or implicit methods utilizing light reflectance of the specimen. This work presents a nondestructive inspection method using ultrasonic wave technology that circumvents these disadvantages to identify phase change regions and infer the temperature state of a material. In the present study an experiment is performed to monitor the time of flight within a wax as it undergoes melting and the subsequent cooling. Results presented in this work show a clear relationship between a material's speed of sound and its temperature. The phase change transition of the material is clear from the time of flight results, and in the case of the investigated material, this change in the material state occurs over a range of temperatures. The range of temperatures over which the wax material melts is readily identified by speed of sound represented as a function of material temperature. The melt temperature, obtained acoustically, is validated using Differential Scanning Calorimetry (DSC), which uses shifts in heat flow rates to identify phase transition temperature ranges. The investigated ultrasonic NDE method has direct applications in many industries, including oil and gas, food and beverage, and polymer composites, in addition to many implications for future capabilities of nondestructive inspection of multi-phase materials.

  8. Study on Energetic Ions Behavior in Plasma Facing Materials at Lower Temperature

    International Nuclear Information System (INIS)

    Morimoto, Y.; Sugiyama, T.; Akahori, S.; Kodama, H.; Tega, E.; Sasaki, M.; Oyaidu, M.; Kimura, H.; Okuno, K.

    2003-01-01

    An apparatus equipped with X-ray Photoelectron Spectroscopy (XPS) and Thermal Desorption Spectroscopy (TDS) was constructed to study interactions of energetic hydrogen isotopes with plasma facing materials. It is a remarkable feature of the apparatus that energetic ion implantation is carried out at around 150K to study reactions of energetic ions with matrix by suppressing the reactions of thermalized ions. Using this apparatus, TDS experiments for pyrolytic graphite implanted with energetic D 2 ions at 173 and 373K were carried out. The experimental results suggest that the deuterium implanted was released through a four-step release processes, involving three D 2 and one CD x (x = 2, 3 and 4) desorption processes. Two deuterium and CD x desorption processes were observed in the temperature range from 700 to 1200 K. In addition, a new deuterium desorption process was observed for the deuterium-implanted sample at 173 K. This has never been observed for deuterium-implanted graphite implanted at temperatures higher than room temperature

  9. The long-range correlation and evolution law of centennial-scale temperatures in Northeast China.

    Science.gov (United States)

    Zheng, Xiaohui; Lian, Yi; Wang, Qiguang

    2018-01-01

    This paper applies the detrended fluctuation analysis (DFA) method to investigate the long-range correlation of monthly mean temperatures from three typical measurement stations at Harbin, Changchun, and Shenyang in Northeast China from 1909 to 2014. The results reveal the memory characteristics of the climate system in this region. By comparing the temperatures from different time periods and investigating the variations of its scaling exponents at the three stations during these different time periods, we found that the monthly mean temperature has long-range correlation, which indicates that the temperature in Northeast China has long-term memory and good predictability. The monthly time series of temperatures over the past 106 years also shows good long-range correlation characteristics. These characteristics are also obviously observed in the annual mean temperature time series. Finally, we separated the centennial-length temperature time series into two time periods. These results reveal that the long-range correlations at the Harbin station over these two time periods have large variations, whereas no obvious variations are observed at the other two stations. This indicates that warming affects the regional climate system's predictability differently at different time periods. The research results can provide a quantitative reference point for regional climate predictability assessment and future climate model evaluation.

  10. 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).

  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. Low Friction and Wear Surface for Application over a Wide Range of Temperature

    National Research Council Canada - National Science Library

    Bhattacharya, Rabi

    1997-01-01

    ...) and Transmission electron microscopy (TEM), both before and after exposure to high temperatures (up to 700 deg C) in air. Friction measurements were performed at temperatures in the range of room temperature to 700 deg C in air...

  13. Creep and low cycles fatigue behaviour of inconel 617 and alloy 800H in the temperature range 1073-1223

    International Nuclear Information System (INIS)

    Yun, H.M.

    1984-01-01

    The creep rupture properties of high temperature alloys are being determined as part of the materials programme for the development of the high temperature, gas-cooled reactor (HTGR) as a source of nuclear process heat, especially for the gasification of lignite and coal. INCOLOY 800H AND INCONEL 617 have been tested in the temperature range from 1073 K to 1223 K in air as well as in helium with HTGR specific impurities. The static and dynamic creep behaviour of INCONEL 617 have been determined in constant load creep tests, relaxation tests and stress reduction tests. The results have been interpreted using the internal stress on the applied stress and test temperature was determined. In a few experiments the influence of cold deformation prior to the creep test on the magnitude of the internal stress was also investigated. (Author)

  14. 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.

  15. 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.

  16. Tribological properties of magnet structural materials at cryogenic temperatures in vacuum

    International Nuclear Information System (INIS)

    Iwabuchi, Akira; Shimizu, Tomoharu; Yoshino, Yasuhiro; Iida, Shin-ichiro; Sugimoto, Makoto; Yoshida, Kiyoshi.

    1994-01-01

    Tribological properties of structural materials of a superconducting magnet for a nuclear fusion reactor were investigated at temperatures of 293 K, 77 K and about 5 K in vacuum. Specimen materials were JN1, JN2 and SUS316L steels, copper and its alloys, and GFRP. The properties of the coefficient of friction against the number of cycles were classified into two groups; smooth friction and fluctuating friction. The latter was caused by the strong adhesion dependent on the material combination and temperature. The coefficient of friction of the smooth friction was low less than 0.6. The upper coefficient of friction of fluctuating friction reaches more than 3. The temperature dependence of the coefficient of friction was also examined from 5 K to 130 K. Combinations of Cu-Cu and JN2-cupronickel showed high friction over the temperature, but JN1-Cu and JN2-Cu showed clear temperature dependence where the friction was high at temperatures between 45 K and 90 K. (author)

  17. Measurement of the high-temperature Seebeck coefficient of thin films by means of an epitaxially regrown thermometric reference material.

    Science.gov (United States)

    Ramu, Ashok T; Mages, Phillip; Zhang, Chong; Imamura, Jeffrey T; Bowers, John E

    2012-09-01

    The Seebeck coefficient of a typical thermoelectric material, silicon-doped InGaAs lattice-matched to InP, is measured over a temperature range from 300 K to 550 K. By depositing and patterning a thermometric reference bar of silicon-doped InP adjacent to a bar of the material under test, temperature differences are measured directly. This is in contrast to conventional two-thermocouple techniques that subtract two large temperatures to yield a small temperature difference, a procedure prone to errors. The proposed technique retains the simple instrumentation of two-thermocouple techniques while eliminating the critical dependence of the latter on good thermal contact. The repeatability of the proposed technique is demonstrated to be ±2.6% over three temperature sweeps, while the repeatability of two-thermocouple measurements is about ±5%. The improved repeatability is significant for reliable reporting of the ZT figure of merit, which is proportional to the square of the Seebeck coefficient. The accuracy of the proposed technique depends on the accuracy with which the high-temperature Seebeck coefficient of the reference material may be computed or measured. In this work, the Seebeck coefficient of the reference material, n+ InP, is computed by rigorous solution of the Boltzmann transport equation. The accuracy and repeatability of the proposed technique can be systematically improved by scaling, and the method is easily extensible to other material systems currently being investigated for high thermoelectric energy conversion efficiency.

  18. 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

  19. Dielectric relaxation in solid collagen over a wide temperature range

    International Nuclear Information System (INIS)

    Khan, Muhammad Abdullah; Rizvi, Tasneem Zahra; Janjua, Khalid Mehmood; Zaheer, Muhammad Yar

    2001-07-01

    Dielectric constant ε' and loss factor ε'' have been measured in bovine tendon collagen in the frequency range 30 Hz - 3 MHz and temperature range 30 deg. C to 200 deg. C. Frequency dependence curve of ε'' shows a low frequency strong α-dispersion attributed to phonon assisted proton hopping between localized sites and a weak high frequency. α 2 - dispersion attributed to reorientation of polar components of collagen molecules. Temperature dependence of the dielectric data show release of bound moisture as a three step process with discrete peaks at 50 deg. C, 90 deg. C and 125 deg. C. These peaks have been attributed to release of adsorbed surface water, water bound to exposed polar sites and strongly bound internal moisture respectively. A peak observed at 160 deg. C has been attributed to thermally induced helix-coil transition of collagen molecules. (author)

  20. 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.

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

    International Nuclear Information System (INIS)

    Naus, Dan J.

    2006-01-01

    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.

  2. Active (air-cooled) vs. passive (phase change material) thermal management of high power lithium-ion packs: Limitation of temperature rise and uniformity of temperature distribution

    Energy Technology Data Exchange (ETDEWEB)

    Sabbah, Rami; Kizilel, R.; Selman, J.R.; Al-Hallaj, S. [Center for Electrochemical Science and Engineering, Department of Chemical and Biological Engineering, Illinois Institute of Technology, 10 W. 33rd Street, Chicago, IL 60616 (United States)

    2008-08-01

    The effectiveness of passive cooling by phase change materials (PCM) is compared with that of active (forced air) cooling. Numerical simulations were performed at different discharge rates, operating temperatures and ambient temperatures of a compact Li-ion battery pack suitable for plug-in hybrid electric vehicle (PHEV) propulsion. The results were also compared with experimental results. The PCM cooling mode uses a micro-composite graphite-PCM matrix surrounding the array of cells, while the active cooling mode uses air blown through the gaps between the cells in the same array. The results show that at stressful conditions, i.e. at high discharge rates and at high operating or ambient temperatures (for example 40-45 C), air-cooling is not a proper thermal management system to keep the temperature of the cell in the desirable operating range without expending significant fan power. On the other hand, the passive cooling system is able to meet the operating range requirements under these same stressful conditions without the need for additional fan power. (author)

  3. Active (air-cooled) vs. passive (phase change material) thermal management of high power lithium-ion packs: Limitation of temperature rise and uniformity of temperature distribution

    Science.gov (United States)

    Sabbah, Rami; Kizilel, R.; Selman, J. R.; Al-Hallaj, S.

    The effectiveness of passive cooling by phase change materials (PCM) is compared with that of active (forced air) cooling. Numerical simulations were performed at different discharge rates, operating temperatures and ambient temperatures of a compact Li-ion battery pack suitable for plug-in hybrid electric vehicle (PHEV) propulsion. The results were also compared with experimental results. The PCM cooling mode uses a micro-composite graphite-PCM matrix surrounding the array of cells, while the active cooling mode uses air blown through the gaps between the cells in the same array. The results show that at stressful conditions, i.e. at high discharge rates and at high operating or ambient temperatures (for example 40-45 °C), air-cooling is not a proper thermal management system to keep the temperature of the cell in the desirable operating range without expending significant fan power. On the other hand, the passive cooling system is able to meet the operating range requirements under these same stressful conditions without the need for additional fan power.

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

    International Nuclear Information System (INIS)

    Honda, Yoshiyuki; Motokoshi, Shinji; Jitsuno, Takahisa; Miyanaga, Noriaki; Fujioka, Kana; Nakatsuka, Masahiro; Yoshida, Minoru

    2014-01-01

    The energy transfer from Cr 3+ to Nd 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 3+ increased with temperature owing to enhancement of the absorption coefficient of Cr 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 3+ to Nd 3+ in Nd/Cr:YAG materials by measuring the temperature dependence of fluorescence characteristics. • The fluorescence intensity of Nd 3+ increased with temperature owing to enhancement of the absorption coefficient of Cr 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

  5. Associations of day-to-day temperature change and diurnal temperature range with out-of-hospital cardiac arrest.

    Science.gov (United States)

    Onozuka, Daisuke; Hagihara, Akihito

    2017-01-01

    Background Although the impacts of temperature on mortality and morbidity have been documented, few studies have investigated whether day-to-day temperature change and diurnal temperature range (DTR) are independent risk factors for out-of-hospital cardiac arrest (OHCA). Design This was a prospective, population-based, observational study. Methods We obtained all OHCA data from 2005-2013 from six major prefectures in Japan: Hokkaido, Tokyo, Kanagawa, Aichi, Kyoto, and Osaka. We used a quasi-Poisson regression analysis with a distributed-lag non-linear model to assess the associations of day-to-day temperature change and DTR with OHCA for each prefecture. Results In total, 271,698 OHCAs of presumed cardiac origin were reported during the study period. There was a significant increase in the risk of OHCA associated with cold temperature in five prefectures, with relative risks (RRs) ranging from 1.298 (95% confidence interval (CI) 1.022-1.649) in Hokkaido to 3.893 (95% CI 1.713-8.845) in Kyoto. DTR was adversely associated with OHCA on hot days in Aichi (RR 1.158; 95% CI 1.028-1.304) and on cold days in Tokyo (RR 1.030; 95% CI 1.000-1.060), Kanagawa (RR 1.042; 95% CI 1.005-1.082), Kyoto (RR 1.060; 95% CI 1.001-1.122), and Osaka (RR 1.050; 95% CI 1.014-1.088), whereas there was no significant association between day-to-day temperature change and OHCA. Conclusion We found that associations between day-to-day temperature change and DTR and OHCA were generally small compared with the association with mean temperature. Our findings suggest that preventative measures for temperature-related OHCA may be more effective when focused on mean temperature and DTR.

  6. Changes in diurnal temperature range and national cereal yields

    Energy Technology Data Exchange (ETDEWEB)

    Lobell, D

    2007-04-26

    Models of yield responses to temperature change have often considered only changes in average temperature (Tavg), with the implicit assumption that changes in the diurnal temperature range (DTR) can safely be ignored. The goal of this study was to evaluate this assumption using a combination of historical datasets and climate model projections. Data on national crop yields for 1961-2002 in the 10 leading producers of wheat, rice, and maize were combined with datasets on climate and crop locations to evaluate the empirical relationships between Tavg, DTR, and crop yields. In several rice and maize growing regions, including the two major nations for each crop, there was a clear negative response of yields to increased DTR. This finding reflects a nonlinear response of yields to temperature, which likely results from greater water and heat stress during hot days. In many other cases, the effects of DTR were not statistically significant, in part because correlations of DTR with other climate variables and the relatively short length of the time series resulted in wide confidence intervals for the estimates. To evaluate whether future changes in DTR are relevant to crop impact assessments, yield responses to projected changes in Tavg and DTR by 2046-2065 from 11 climate models were estimated. The mean climate model projections indicated an increase in DTR in most seasons and locations where wheat is grown, mixed projections for maize, and a general decrease in DTR for rice. These mean projections were associated with wide ranges that included zero in nearly all cases. The estimated impacts of DTR changes on yields were generally small (<5% change in yields) relative to the consistently negative impact of projected warming of Tavg. However, DTR changes did significantly affect yield responses in several cases, such as in reducing US maize yields and increasing India rice yields. Because DTR projections tend to be positively correlated with Tavg, estimates of yields

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

    International Nuclear Information System (INIS)

    2014-01-01

    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

  8. 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

  9. Physical activity profile of 2014 FIFA World Cup players, with regard to different ranges of air temperature and relative humidity

    Science.gov (United States)

    Chmura, Paweł; Konefał, Marek; Andrzejewski, Marcin; Kosowski, Jakub; Rokita, Andrzej; Chmura, Jan

    2017-04-01

    The present study attempts to assess changes in soccer players' physical activity profiles under the simultaneous influence of the different combinations of ambient temperature and relative humidity characterising matches of the 2014 FIFA World Cup hosted by Brazil. The study material consisted of observations of 340 players representing 32 national teams taking part in the tournament. The measured indices included total distances covered; distances covered with low, moderate, or high intensity; numbers of sprints performed, and peak running speeds achieved. The analysis was carried out using FIFA official match data from the Castrol Performance Index system. Ultimately, consideration was given to a combination of three air temperature ranges, i.e. below 22 °C, 22-28 °C, and above 28 °C; and two relative humidity ranges below 60 % and above 60 %. The greatest average distance recorded (10.54 ± 0.91 km) covered by players at an air temperature below 22 °C and a relative humidity below 60 %, while the shortest (9.83 ± 1.08 km) characterised the same air temperature range, but conditions of relative humidity above 60 % ( p ≤ 0.001). Two-way ANOVA revealed significant differences ( p ≤ 0.001) in numbers of sprints performed by players, depending on whether the air temperature range was below 22 °C (40.48 ± 11.17) or above 28 °C (30.72 ± 9.40), but only where the relative humidity was at the same time below 60 %. Results presented indicate that the conditions most comfortable for physical activity on the part of players occur at 22 °C, and with relative humidity under 60 %.

  10. Relationship between Magnetic Anisotropy below Pseudogap Temperature and Short-Range Antiferromagnetic Order in High-Temperature Cuprate Superconductor

    Science.gov (United States)

    Morinari, Takao

    2018-06-01

    The central issue in high-temperature cuprate superconductors is the pseudogap state appearing below the pseudogap temperature T*, which is well above the superconducting transition temperature. In this study, we theoretically investigate the rapid increase of the magnetic anisotropy below the pseudogap temperature detected by the recent torque-magnetometry measurements on YBa2Cu3Oy [Y. Sato et al., 10.1038/nphys4205" xlink:type="simple">Nat. Phys. 13, 1074 (2017)]. Applying the spin Green's function formalism including the Dzyaloshinskii-Moriya interaction arising from the buckling of the CuO2 plane, we obtain results that are in good agreement with the experiment and find a scaling relationship. Our analysis suggests that the characteristic temperature associated with the magnetic anisotropy, which coincides with T*, is not a phase transition temperature but a crossover temperature associated with the short-range antiferromagnetic order.

  11. Passive Wireless Temperature Sensors with Enhanced Sensitivity and Range, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This proposal describes the development of passive surface acoustic wave (SAW) temperature sensors with enhanced sensitivity and detection range for NASA application...

  12. Nuclear fuels for very high temperature applications

    International Nuclear Information System (INIS)

    Lundberg, L.B.; Hobbins, R.R.

    1992-01-01

    The success of the development of nuclear thermal propulsion devices and thermionic space nuclear power generation systems depends on the successful utilization of nuclear fuel materials at temperatures in the range 2000 to 3500 K. Problems associated with the utilization of uranium bearing fuel materials at these very high temperatures while maintaining them in the solid state for the required operating times are addressed. The critical issues addressed include evaporation, melting, reactor neutron spectrum, high temperature chemical stability, fabrication, fission induced swelling, fission product release, high temperature creep, thermal shock resistance, and fuel density, both mass and fissile atom. Candidate fuel materials for this temperature range are based on UO 2 or uranium carbides. Evaporation suppression, such as a sealed cladding, is required for either fuel base. Nuclear performance data needed for design are sparse for all candidate fuel forms in this temperature range, especially at the higher temperatures

  13. Determination of plant growth rate and growth temperature range from measurement of physiological parameters

    Science.gov (United States)

    R. S. Criddle; B. N. Smith; L. D. Hansen; J. N. Church

    2001-01-01

    Many factors influence species range and diversity, but temperature and temperature variability are always major global determinants, irrespective of local constraints. On a global scale, the ranges of many taxa have been observed to increase and their diversity decrease with increasing latitude. On a local scale, gradients in species distribution are observable with...

  14. High Temperature Electrical Insulation Materials for Space Applications, Phase I

    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...

  15. A green synthesis of a layered titanate, potassium lithium titanate; lower temperature solid-state reaction and improved materials performance

    International Nuclear Information System (INIS)

    Ogawa, Makoto; Morita, Masashi; Igarashi, Shota; Sato, Soh

    2013-01-01

    A layered titanate, potassium lithium titanate, with the size range from 0.1 to 30 µm was prepared to show the effects of the particle size on the materials performance. The potassium lithium titanate was prepared by solid-state reaction as reported previously, where the reaction temperature was varied. The reported temperature for the titanate preparation was higher than 800 °C, though 600 °C is good enough to obtain single-phase potassium lithium titanate. The lower temperature synthesis is cost effective and the product exhibit better performance as photocatalysts due to surface reactivity. - Graphical abstract: Finite particle of a layered titanate, potassium lithium titanate, was prepared by solid-state reaction at lower temperature to show modified materials performance. Display Omitted - Highlights: • Potassium lithium titanate was prepared by solid-state reaction. • Lower temperature reaction resulted in smaller sized particles of titanate. • 600 °C was good enough to obtain single phased potassium lithium titanate. • The product exhibited better performance as photocatalyst

  16. Seeing the light: the effects of particles, dissolved materials, and temperature on in situ measurements of DOM fluorescence in rivers and streams

    Science.gov (United States)

    Downing, Bryan D.; Pellerin, Brian A.; Bergamaschi, Brian A.; Saraceno, John Franco; Kraus, Tamara E.C.

    2012-01-01

    Field-deployable sensors designed to continuously measure the fluorescence of colored dissolved organic matter (FDOM) in situ are of growing interest. However, the ability to make FDOM measurements that are comparable across sites and over time requires a clear understanding of how instrument characteristics and environmental conditions affect the measurements. In particular, the effects of water temperature and light attenuation by both colored dissolved material and suspended particles may be significant in settings such as rivers and streams. Using natural standard reference materials, we characterized the performance of four commercially-available FDOM sensors under controlled laboratory conditions over ranges of temperature, dissolved organic matter (DOM) concentrations, and turbidity that spanned typical environmental ranges. We also examined field data from several major rivers to assess how often attenuation artifacts or temperature effects might be important. We found that raw (uncorrected) FDOM values were strongly affected by the light attenuation that results from dissolved substances and suspended particles as well as by water temperature. Observed effects of light attenuation and temperature agreed well with theory. Our results show that correction of measured FDOM values to account for these effects is necessary and feasible over much of the range of temperature, DOM concentration, and turbidity commonly encountered in surface waters. In most cases, collecting high-quality FDOM measurements that are comparable through time and between sites will require concurrent measurements of temperature and turbidity, and periodic discrete sample collection for laboratory measurement of DOM.

  17. 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.

  18. 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.

  19. High Temperature Materials Interim Data Qualification Report FY 2011

    International Nuclear Information System (INIS)

    Lybeck, Nancy

    2011-01-01

    Projects for the very high temperature reactor (VHTR) Technology Development Office provide data in support of Nuclear Regulatory Commission licensing of the VHTR. Fuel and materials to be used in the reactor are tested and characterized to quantify performance in high temperature and high fluence environments. The VHTR program has established the Next Generation Nuclear Plant (NGNP) Data Management and Analysis System (NDMAS) to ensure that VHTR data are qualified for use, stored in a readily accessible electronic form, and analyzed to extract useful results. This document focuses on the first NDMAS objective. It describes the High Temperature Materials characterization data stream, the processing of these data within NDMAS, and reports the interim fiscal year (FY) 2011 qualification status of the data. Data qualification activities within NDMAS for specific types of data are determined by the data qualification category assigned by the data generator. The High Temperature Materials data are being collected under the Nuclear Quality Assurance (NQA)-1 guidelines and will be qualified data. For NQA-1 qualified data, the qualification activities include: (1) capture testing to confirm that the data stored within NDMAS are identical to the raw data supplied, (2) accuracy testing to confirm that the data are an accurate representation of the system or object being measured, and (3) documenting that the data were collected under an NQA-1 or equivalent Quality Assurance program. Currently, data from seven test series within the High Temperature Materials data stream have been entered into the NDMAS vault, including tensile tests, creep tests, and cyclic tests. Of the 5,603,682 records currently in the vault, 4,480,444 have been capture passed, and capture testing is in process for the remaining 1,123,238.

  20. Laser application in high temperature materials

    International Nuclear Information System (INIS)

    Ohse, R.W.

    1988-01-01

    The scope and priorities of laser application in materials science and technology are attracting widespread interest. After a brief discussion of the unique capabilities of laser application in the various fields of materials science, main emphasis is given on the three areas of materials processing, surface modification and alloying, and property measurements at high temperatures. In materials processing the operational regimes for surface hardening, drilling, welding and laser glazing are discussed. Surface modifications by laser melting, quenching and surface alloying, the formation of solid solutions, metastable phases and amorphous solids on the basis of rapid solidification, ion implantation and ion beam mixing are considered. The influence of solidification rates and interface velocities on the surface properties are given. The extension of property measurements up to and beyond the melting point of refractory materials into their critical region by a transient-type dynamic laser pulse heating technique is given for the three examples of vapour pressure measurement, density and heat capacity determination in the solid and liquid phases. A new approach, the laser autoclave technique, applying laser heating and x-ray shadow technique under autoclave conditions to acoustically levitated spheres will be presented. (author)

  1. Materials for advanced high temperature reactors

    International Nuclear Information System (INIS)

    Graham, L.W.

    1977-01-01

    Materials are studied in advanced applications of high temperature reactors: helium gas turbine and process heat. Long term creep behavior and corrosion tests are conducted in simulated HTR helium up to 1000 deg C with impurities additions in the furnace atmosphere. Corrosion studies on AISI 321 steels at 800-1000 deg C have shown that the O 2 partial pressure is as low as 10 -24+-3 atm, Ni and Fe cannot be oxidised above about 500 and 600 deg C, Cr cease to oxidise at 800 to 900 deg C and Ti at 900 to 1000 deg C depending on alloy composition γ' strengthened superalloys must depend on a protective corrosion mechanism assisted by the presence of Ti and possibly Cr. Carburisation has been identified metallographically in several high temperature materials: Hastelloy X and M21Z. Alloy TZM appears to be inert in HTR Helium at 900 and 1000 deg C. In alloy 800 and Inconel 625 surface cracks initiation is suppressed but crack propagation is accelerated but this was not apparent in AISI steels, Hastelloy X or fine grain Inconel at 750 deg C

  2. 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.

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

    International Nuclear Information System (INIS)

    Huang, Xiaochen; Yu, Bin; Yan, X.G.; Li, D.Y.

    2016-01-01

    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. Increasing sea surface temperature and range shifts of intertidal gastropods along the Iberian Peninsula

    Science.gov (United States)

    Rubal, Marcos; Veiga, Puri; Cacabelos, Eva; Moreira, Juan; Sousa-Pinto, Isabel

    2013-03-01

    There are well-documented changes in abundance and geographical range of intertidal invertebrates related to climate change at north Europe. However, the effect of sea surface warming on intertidal invertebrates has been poorly studied at lower latitudes. Here we analyze potential changes in the abundance patterns and distribution range of rocky intertidal gastropods related to climate change along the Iberian Peninsula. To achieve this aim, the spatial distribution and range of sub-tropical, warm- and cold-water species of intertidal gastropods was explored by a fully hierarchical sampling design considering four different spatial scales, i.e. from region (100 s of km apart) to quadrats (ms apart). Variability on their patterns of abundance was explored by analysis of variance, changes on their distribution ranges were detected by comparing with previous records and their relationship with sea water temperature was explored by rank correlation analyses. Mean values of sea surface temperature along the Iberian coast, between 1949 and 2010, were obtained from in situ data compiled for three different grid squares: south Portugal, north Portugal, and Galicia. Lusitanian species did not show significant correlation with sea water temperature or changes on their distributional range or abundance, along the temperature gradient considered. The sub-tropical species Siphonaria pectinata has, however, increased its distribution range while boreal cold-water species showed the opposite pattern. The latter was more evident for Littorina littorea that was almost absent from the studied rocky shores of the Iberian Peninsula. Sub-tropical and boreal species showed significant but opposite correlation with sea water temperature. We hypothesized that the energetic cost of frequent exposures to sub-lethal temperatures might be responsible for these shifts. Therefore, intertidal gastropods at the Atlantic Iberian Peninsula coast are responding to the effect of global warming as it

  5. 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

  6. 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.

  7. MTF measurement of IR optics in different temperature ranges

    Science.gov (United States)

    Bai, Alexander; Duncker, Hannes; Dumitrescu, Eugen

    2017-10-01

    Infrared (IR) optical systems are at the core of many military, civilian and manufacturing applications and perform mission critical functions. To reliably fulfill the demanding requirements imposed on today's high performance IR optics, highly accurate, reproducible and fast lens testing is of crucial importance. Testing the optical performance within different temperature ranges becomes key in many military applications. Due to highly complex IR-Applications in the fields of aerospace, military and automotive industries, MTF Measurement under realistic environmental conditions become more and more relevant. A Modulation Transfer Function (MTF) test bench with an integrated thermal chamber allows measuring several sample sizes in a temperature range from -40 °C to +120°C. To reach reliable measurement results under these difficult conditions, a specially developed temperature stable design including an insulating vacuum are used. The main function of this instrument is the measurement of the MTF both on- and off-axis at up to +/-70° field angle, as well as measurement of effective focal length, flange focal length and distortion. The vertical configuration of the system guarantees a small overall footprint. By integrating a high-resolution IR camera with focal plane array (FPA) in the detection unit, time consuming measurement procedures such as scanning slit with liquid nitrogen cooled detectors can be avoided. The specified absolute accuracy of +/- 3% MTF is validated using internationally traceable reference optics. Together with a complete and intuitive software solution, this makes the instrument a turn-key device for today's state-of- the-art optical testing.

  8. Elaboration of high-temperature friction polymer material and study of its wear aspects

    International Nuclear Information System (INIS)

    Gventsadze, L.

    2009-01-01

    High-temperature friction composite material is elaborated and its physical, mechanical and tribologic features are studied. It is shown, that addition to the friction material composition of filling material having nanopores -diatomite-and its modification with polyethilensilan leads to friction materials friction coefficient stability and wear resistance increase at high temperatures (400-600 ℃). (author)

  9. Effect of annealing temperature and dopant concentration on the thermoluminescence sensitivity in LiF:Mg,Cu,Ag material.

    Science.gov (United States)

    Yahyaabadi, Akram; Torkzadeh, Falamarz; Rezaei Ochbelagh, Dariush; Hosseini Pooya, Seyed Mahdi

    2018-04-24

    LiF:Mg,Cu,Ag is a new dosimetry material that is similar to LiF:Mg,Cu,P in terms of dosimetric properties. The effect of the annealing temperature in the range of 200 to 350°C on the thermoluminescence (TL) sensitivity and the glow curve structure of this material at different concentrations of silver (Ag) was investigated. It has been demonstrated that the optimum values of the annealing temperature and the Ag concentration are 240°C and 0.1 mol% for better sensitivity, respectively. The TL intensity decreases at annealing temperatures lower than 240°C or higher than 240°C, reaching a minimum at 300°C and then again increases for various Ag concentrations. It was observed that the glow curve structure altered and the area under the low temperature peak as well as the area under the main dosimetric peak decreased with increasing annealing temperature. The position of the main dosimetric peak moved in the direction of higher temperatures, but at 320 and 350°C annealing temperatures, it shifted to lower temperatures. It was also observed that the TL sensitivity could partially be recovered by a combined annealing procedure. Copyright © 2018 John Wiley & Sons, Ltd.

  10. 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

  11. Measurement of bulk etch rates for poly-allyl-diglycol carbonate (PADC) and cellulose nitrate in a broad range of concentration and temperature of NaOH etching solution

    International Nuclear Information System (INIS)

    Hermsdorf, D.; Hunger, M.; Starke, S.; Weickert, F.

    2007-01-01

    In the present work the dependence of the bulk etch rate v B for solid state nuclear track detectors (SSNTD) on the concentration c and the temperature T of the NaOH etching solution has been studied for material types PADC and cellulose nitrate. As commonly applied exponents of PADC and cellulose nitrate material, the commercial products CR-39 and LR-115 were investigated. The concentration and temperature have been varied in the ranges 0.5moll -1 -1 and 313 -1 and T between 313 and 333K for cellulose nitrate, respectively. The application of a simple Arrhenius-law of chemical reactions fails in the interpretation of the dependence on the concentration. A constant activation energy cannot describe the behaviour of v B (c,T) over the whole range of concentration. To understand the deviation, more qualified models treating the superposition of chemical and physical processes including reaction kinetics and material transport phenomena by diffusion have to be developed and tested

  12. 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.

  13. Carbon nanotube scaffolds with controlled porosity as electromagnetic absorbing materials in the gigahertz range

    Science.gov (United States)

    González, M.; Crespo, M.; Baselga, J.; Pozuelo, J.

    2016-05-01

    Control of the microscopic structure of CNT nanocomposites allows modulation of the electromagnetic shielding in the gigahertz range. The porosity of CNT scaffolds has been controlled by two freezing protocols and a subsequent lyophilization step: fast freezing in liquid nitrogen and slow freezing at -20 °C. Mercury porosimetry shows that slowly frozen specimens present a more open pore size (100-150 μm) with a narrow distribution whereas specimens frozen rapidly show a smaller pore size and a heterogeneous distribution. 3D-scaffolds containing 3, 4, 6 and 7% CNT were infiltrated with epoxy and specimens with 2, 5 and 8 mm thicknesses were characterized in the GHz range. Samples with the highest pore size and porosity presented the lowest reflected power (about 30%) and the highest absorbed power (about 70%), which allows considering them as electromagnetic radiation absorbing materials.Control of the microscopic structure of CNT nanocomposites allows modulation of the electromagnetic shielding in the gigahertz range. The porosity of CNT scaffolds has been controlled by two freezing protocols and a subsequent lyophilization step: fast freezing in liquid nitrogen and slow freezing at -20 °C. Mercury porosimetry shows that slowly frozen specimens present a more open pore size (100-150 μm) with a narrow distribution whereas specimens frozen rapidly show a smaller pore size and a heterogeneous distribution. 3D-scaffolds containing 3, 4, 6 and 7% CNT were infiltrated with epoxy and specimens with 2, 5 and 8 mm thicknesses were characterized in the GHz range. Samples with the highest pore size and porosity presented the lowest reflected power (about 30%) and the highest absorbed power (about 70%), which allows considering them as electromagnetic radiation absorbing materials. Electronic supplementary information (ESI) available: Scheme of hydrogenated derivative of diglycidyl ether of bisphenol-A (HDGEBA) and m-xylylenediamine; X-ray diffractograms of pristine CNT

  14. Apparatus for dynamic measurement of gases released from materials heated under programmed temperature-time control

    International Nuclear Information System (INIS)

    Early, J.W.; Abernathey, R.M.

    1982-04-01

    This apparatus, a prototype of one being constructed for hotcell examination of irradiated nuclear materials, measures dynamic release rates and integrated volumes of individual gases from materials heated under controlled temperature-time programs. It consists of an inductively heated vacuum furnace connected to a quadrupole mass spectrometer. A computerized control system with data acquisition provides scanning rates down to 1s and on-line tabular and graphic displays. Heating rates are up to 1300 0 C/min to a maximum temperature of 2000 0 C. The measurement range is about 10 -6 to 10 -2 torr-liter/s for H 2 , CH 4 , H 2 O, N 2 , and CO and 10 -8 to 10 -2 torr-liter/s for He, Kr, and Xe. Applications are described for measurements of Kr and Xe in mixed oxide fuel, various gases in UO 2 pellets, and He in 238 PuO 2 power and heat sources

  15. Density of Liquid Steel over Temperature Range of 1 803-1 873 K

    Institute of Scientific and Technical Information of China (English)

    XIAO Feng; FANG Liang

    2004-01-01

    The density of three kinds of liquid steel was measured by a modified sessile drop method over the temperature range of 1 803-1 873 K. It is found that the density of liquid steels decreases with increasing temperature and carbon content in steel. Both of the density and its absolute temperature coefficient of studied steels are smaller than the literature values of pure iron. The molar volume of the steels increases with increasing temperature.

  16. An investigation of high-temperature irradiation test program of new ceramic materials

    International Nuclear Information System (INIS)

    Ishino, Shiori; Terai, Takayuki; Oku, Tatsuo

    1999-08-01

    The Japan Atomic Energy Research Institute entrusted the Atomic Energy Society of Japan with an investigation into the trend of irradiation processing/damage research on new ceramic materials. The present report describes the result of the investigation, which was aimed at effective execution of irradiation programs using the High Temperature Engineering Test Reactor (HTTR) by examining preferential research subjects and their concrete research methods. Objects of the investigation were currently on-going preliminary tests of functional materials (high-temperature oxide superconductor and high-temperature semiconductor) and structural materials (carbon/carbon and SiC/SiC composite materials), together with newly proposed subjects of, e.g., radiation effects on ceramics-coated materials and super-plastic ceramic materials as well as microscopic computer simulation of deformation and fracture of ceramics. These works have revealed 1) the background of each research subject, 2) its objective and significance from viewpoints of science and engineering, 3) research methodology in stages from preliminary tests to real HTTR irradiation, and 4) concrete HTTR-irradiation methods which include main specifications of test specimens, irradiation facilities and post-irradiation examination facilities and apparatuses. The present efforts have constructed the important fundamentals in the new ceramic materials field for further planning and execution of the innovative basic research on high-temperature engineering. (author)

  17. Generalization of Coffin-Manson relation in connection with the low-cycle fatigue in the temperature range 20-300 o C

    International Nuclear Information System (INIS)

    Radu, V.

    1992-01-01

    The low-cycle fatigue phenomenon in the framework of plastic deformation is studied considering the temperature parameter. The experimental results obtained for the plastic strain Δε p (1-7%), in the temperature range 20-300 o C are examined. The conclusion is that the lifetime, expressed by the number of stress cycles, N f , is given by the relation N f = C exp(-A/T)(Δε p ) β+αΔT , where T is the absolute temperature, Δε p is double of plastic deformation amplitude, and C, A, β, and α are material constants. This relation can be interpreted as being the generalization of a relation, known in literature as the 'Coffin-Manson relation', but which does not include the temperature parameter. The validation of this relation can be done either on the results presented in this paper or an those published in literature. (Author)

  18. Energy based model for temperature dependent behavior of ferromagnetic materials

    International Nuclear Information System (INIS)

    Sah, Sanjay; Atulasimha, Jayasimha

    2017-01-01

    An energy based model for temperature dependent anhysteretic magnetization curves of ferromagnetic materials is proposed and benchmarked against experimental data. This is based on the calculation of macroscopic magnetic properties by performing an energy weighted average over all possible orientations of the magnetization vector. Most prior approaches that employ this method are unable to independently account for the effect of both inhomogeneity and temperature in performing the averaging necessary to model experimental data. Here we propose a way to account for both effects simultaneously and benchmark the model against experimental data from ~5 K to ~300 K for two different materials in both annealed (fewer inhomogeneities) and deformed (more inhomogeneities) samples. This demonstrates that this framework is well suited to simulate temperature dependent experimental magnetic behavior. - Highlights: • Energy based model for temperature dependent ferromagnetic behavior. • Simultaneously accounts for effect of temperature and inhomogeneities. • Benchmarked against experimental data from 5 K to 300 K.

  19. Germanium thermometers in the temperature range .1000K to 4.20K

    International Nuclear Information System (INIS)

    Hsieh, S.Y.; Sanchez, D.H.

    1974-01-01

    The sensitivity characteristics of two germanium thermometers that proved to be convenient sensors in the temperature range from .100 0 K to 4.2 0 K, are described. Their resistances change from about 8 x 10 5 ohms at .100 0 K to about 100 ohms at 4.2 0 K. The calibration curves were fitted to natural spline functions of order 3 in the whole range of temperatures. These functions give less than half millidegree standard dispersion against 15 millidegree standard dispersion when usual polynomial interpolations are used. It is discussed what spline functions are, and compare the goodness of spline interpolation with polynomial methods [pt

  20. A novel magnetic valve using room temperature magnetocaloric materials

    DEFF Research Database (Denmark)

    Eriksen, Dan; Bahl, Christian; Pryds, Nini

    2012-01-01

    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...

  1. Low temperature distillation of powdered materials

    Energy Technology Data Exchange (ETDEWEB)

    1929-04-11

    In the low temperature distillation of powdered material such as coal, brown coal, or oil shale, dust carried by the gases and vapors is precipitated by supplying liquid hydrocarbons to the effluent gases, for example, to a dust remover through which the distillates pass. The material is supplied through a hopper and moved through a retort by a worm feed, and is discharged into a sump. Scavenging gases such as steam may be introduced through a pipe. Two conveyor worms moving in opposite directions are provided in an outlet conduit which may be surrounded by a cooling jacket. Heavy hydrocarbons condense on the walls of the conduit and on the conveyor worms and serve as dust catchers for the distillates, the lighted volatiles escaping through an outlet. The high boiling point oils flow back to and are cracked in the retort. Oils such as tar oils may be sprayed into the conduit or directly adjacent the entry of the material from feeding hopper.

  2. Spectral emissivity measurements of candidate materials for very high temperature reactors

    Energy Technology Data Exchange (ETDEWEB)

    Cao, G.; Weber, S.J.; Martin, S.O.; Anderson, M.H. [Department of Engineering Physics, University of Wisconsin, 1500 Engineering Drive, Madison, WI (United States); Sridharan, K., E-mail: kumars@cae.wisc.edu [Department of Engineering Physics, University of Wisconsin, 1500 Engineering Drive, Madison, WI (United States); Allen, T.R. [Department of Engineering Physics, University of Wisconsin, 1500 Engineering Drive, Madison, WI (United States)

    2012-10-15

    Heat dissipation by radiation is an important consideration in VHTR components, particularly the reactor pressure vessel (RPV), because of the fourth power temperature dependence of radiated heat. Since emissivity is the material property that dictates the ability to radiate heat, measurements of emissivities of materials that are being specifically considered for the construction of VHTR become important. Emissivity is a surface phenomenon and therefore compositional, structural, and topographical changes that occur at the surfaces of these materials as a result of their interactions with the environment at high temperatures will alter their emissivities. With this background, an experimental system for the measurement of spectral emissivity has been designed and constructed. The system has been calibrated in conformance with U.S. DoE quality assurance standards using inert ceramic materials, boron nitride, silicon carbide, and aluminum oxide. The results of high temperature emissivity measurements of potential VHTR materials such as ferritic steels SA 508, T22, T91 and austenitic alloys IN 800H, Haynes 230, IN 617, and 316 stainless steel have been presented.

  3. 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

  4. Wide-range vortex shedding flowmeter for high-temperature helium gas

    Energy Technology Data Exchange (ETDEWEB)

    Baker, S.P.; Herndon, P.G.; Ennis, R.M. Jr.

    1983-01-01

    The existing design of a commercially available vortex shedding flowmeter (VSFM) was modified and optimized to produce three 4-in. and one 6-in. high-performance VSFMs for measuring helium flow in a gas-cooled fast reactor (GCFR) test loop. The project was undertaken because of the significant economic and performance advantages to be realized by using a single flowmeter capable of covering the 166:1 flow range (at 350/sup 0/C and 45:1 pressure range) of the tests. A detailed calibration in air and helium at the Colorado Engineering Experiment Station showed an accuracy of +-1% of reading for a 100:1 helium flow range and +-1.75% of reading for a 288:1 flow range in both helium and air. At an extended gas temperature of 450/sup 0/C, water cooling was necessary for reliable flowmeter operation.

  5. Material design data of 2.25Cr-1Mo steel and hastelloy-x for the experimental multi-purpose very-high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Kodaira, Tsuneo; Suzuki, Michiaki; Uga, Takeo

    1975-08-01

    The preliminary structural design guidelines for the experimental multi-purpose very-high temperature gas-cooled reactor have recently been prepared. The components of the primary system operating at temperatures of creep dominant range are grouped in those of pressure and temperature boundaries respectively. In the material selection, 2 1/4Cr-1Mo steel is chosen for the former and Hastelloy-X for the latter taking into account of material properties at operating temperature. Deriving from the literature in the field, material design data of the alloys are established in design forms such as Sy, So, Sm, St, 100% of minimum stress to rupture, design fatigue curves, isochronous stress-strain curves, creep-fatigue interaction damage factor and so on, which are defined in ASME Code Section III, Code Case 1592. (auth.)

  6. Ultra light weight refractory material for high temperature applications

    Energy Technology Data Exchange (ETDEWEB)

    Finke, V.; Kern, H. [Rath GmbH, Meissen (Germany); Springer, M. [Aug. Rath jun. GmbH, Vienna (Austria)

    2007-07-01

    The requirements on companies running high temperature processes, i.e. at temperatures about 1000 C and above, have increased dramatically within the last few years. For technological, economical and ecological purposes each application has to be checked carefully. As well the political discussion regarding environmental pollution, greenhouse effect and emission trading and the guidelines for climate and environmental protection exert massive influence on thermal process technology and pose an appropriate challenge for the companies. Next to costs of labour and raw materials the costs for energy and environmental costs play a decisive role more and more. The pressure on the management thereby incurred may have a lasting effect on innovations regarding increase of energy efficiency, decrease of CO{sub 2}-emission and often on non negligible increase of productivity. Mainly against the background of the highly scheduled European aims for emission reduction and also in consideration of the still proceeding globalisation the usage of state-of-the-art refractory technics in thermal process technology is of particular importance for business success, for reducing of environmental impact and last but not least for conservation and safeguarding of jobs in Europe and Germany. The applications for products made from high-temperature insulation wool in high temperature applications have strongly increased during the last five years. Especially the production capacities of polycrystalline wool (aluminium oxide wool e.g. Altra B72) have been doubled within the last three years. Primarily ultra light weight products made from HTIW are used in industrial furnaces with application temperatures above 1000 C and / or with high thermo-mechanical (thermal shock) and chemical exposure. The outstanding and essential advantages of these materials are obviously: Ultra light weight material with high resilience and flexibility, Optimised energy consumption (energy saving up to 50% compared

  7. Thermal properties and modeling of aluminosilicate materials for low-temperature bulk applications

    International Nuclear Information System (INIS)

    Kaushal, S.

    1988-01-01

    This thesis concerns itself with the thermal properties of aluminosilicate materials such as cements, blended cements and clays and their application to the problem of radioactive waste encapsulation. The objective of this thesis is to study the thermal properties (heat of hydration, thermal conductivity and diffusivity) of these materials and to determine their effect on the temperature in large monoliths and on the material itself. In this thesis the hydration temperatures for the extreme conditions (adiabatic) were experimentally measured and compared to those predicted under real conditions. Such a simulation can be made by measuring the thermal properties and studying the temperature distribution predicted by a finite differences computer model. Measurements of adiabatic temperature rise were made using a computer-controlled adiabatic calorimeter which was designed and developed for this thesis. Conditions very close to zero heat exchange with the environment were achieved. The existence of this method made it possible to actually observe the fact that cement hydration results in boiling off of the water in such conditions. A number of additives were tried to prevent this. It was observed that waste or by-product materials such as blast furnace slag and fly ash could be used to dramatically reduced the temperature in large bodies. These materials also reacted extensively with the highly alkaline radioactive waste solution to form hydrogarnet and zeolitic material which had useful cementing properties. The conclusion was reached that a selection of blends of aluminosilicate materials can be utilized for providing the proper thermal environment for long-term geological disposal of radioactive waste

  8. Sound absorption of low-temperature reusable surface insulation candidate materials

    Science.gov (United States)

    Johnston, J. D.

    1974-01-01

    Sound absorption data from tests of four candidate low-temperature reusable surface insulation materials are presented. Limitations on the use of the data are discussed, conclusions concerning the effective absorption of the materials are drawn, and the relative significance to Vibration and Acoustic Test Facility test planning of the absorption of each material is assessed.

  9. An Investigation on Attributes of Ambient Temperature and Diurnal Temperature Range on Mortality in Five East-Asian Countries.

    Science.gov (United States)

    Lee, Whan-Hee; Lim, Youn-Hee; Dang, Tran Ngoc; Seposo, Xerxes; Honda, Yasushi; Guo, Yue-Liang Leon; Jang, Hye-Min; Kim, Ho

    2017-08-31

    Interest in the health effects of extremely low/high ambient temperature and the diurnal temperature range (DTR) on mortality as representative indices of temperature variability is growing. Although numerous studies have reported on these indices independently, few studies have provided the attributes of ambient temperature and DTR related to mortality, concurrently. In this study, we aimed to investigate and compare the mortality risk attributable to ambient temperature and DTR. The study included data of 63 cities in five East-Asian countries/regions during various periods between 1972 and 2013. The attributable risk of non-accidental death to ambient temperature was 9.36% (95% confidence interval [CI]: 8.98-9.69%) and to DTR was 0.59% (95% CI: 0.53-0.65%). The attributable cardiovascular mortality risks to ambient temperature (15.63%) and DTR (0.75%) are higher than the risks to non-accidental/respiratory-related mortality. We verified that ambient temperature plays a larger role in temperature-associated mortality, and cardiovascular mortality is susceptible to ambient temperature and DTR.

  10. Materials for advanced high temperature reactors

    International Nuclear Information System (INIS)

    Graham, L.W.

    1976-01-01

    The results recently obtained from the Dragon program are presented to illustrate materials behavior: (a) effect of temperature on oxidation and carburisation in HTR helium (variation in oxide depth and in C content of AISI 321 after 5000 hours in HTR helium; effect of temperature on surface scale formation in the γ' strengthened alloys Nimonic 80A and 713LC); (b) effect of alloy composition on oxidation and carburisation behavior (influence of Nb and Ti on the corrosion of austenitic steels; influence of Ti and Al in IN-102; weight gain of cast high Ni alloys); (c) effect of environment on creep strength (results of tests for hastelloy X, grade I inconel 625, grade II inconel 625 and inconel 617 in He and air between 750 and 800 0 C)

  11. 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

  12. Interlot variations of transition temperature range and force delivery in copper-nickel-titanium orthodontic wires.

    Science.gov (United States)

    Pompei-Reynolds, Renée C; Kanavakis, Georgios

    2014-08-01

    The manufacturing process for copper-nickel-titanium archwires is technique sensitive. The primary aim of this investigation was to examine the interlot consistency of the mechanical properties of copper-nickel-titanium wires from 2 manufacturers. Wires of 2 sizes (0.016 and 0.016 × 0.022 in) and 3 advertised austenite finish temperatures (27°C, 35°C, and 40°C) from 2 manufacturers were tested for transition temperature ranges and force delivery using differential scanning calorimetry and the 3-point bend test, respectively. Variations of these properties were analyzed for statistical significance by calculating the F statistic for equality of variances for transition temperature and force delivery in each group of wires. All statistical analyses were performed at the 0.05 level of significance. Statistically significant interlot variations in austenite finish were found for the 0.016 in/27°C (P = 0.041) and 0.016 × 0.022 in/35°C (P = 0.048) wire categories, and in austenite start for the 0.016 × 0.022 in/35°C wire category (P = 0.01). In addition, significant variations in force delivery were found between the 2 manufacturers for the 0.016 in/27°C (P = 0.002), 0.016 in/35.0°C (P = 0.049), and 0.016 × 0.022 in/35°C (P = 0.031) wires. Orthodontic wires of the same material, dimension, and manufacturer but from different production lots do not always have similar mechanical properties. Clinicians should be aware that copper-nickel-titanium wires might not always deliver the expected force, even when they come from the same manufacturer, because of interlot variations in the performance of the material. Copyright © 2014 American Association of Orthodontists. Published by Mosby, Inc. All rights reserved.

  13. Cadmium Manganese Telluride (Cd1-xMnxTe): A potential material for room-temperature radiation detectors

    Energy Technology Data Exchange (ETDEWEB)

    Hossain, A.; Cui, Y.; Bolotnikov, A.; Camarda, G.; Yang, G.; Kim, K-H.; Gul, R.; Xu, L.; Li, L.; Mycielski, A.; and James, R.B.

    2010-07-11

    Cadmium Manganese Telluride (CdMnTe) recently emerged as a promising material for room-temperature X- and gamma-ray detectors. It offers several potential advantages over CdZnTe. Among them is its optimal tunable band gap ranging from 1.7-2.2 eV, and its relatively low (< 50%) content of Mn compared to that of Zn in CdZnTe that assures this favorable band-gap range. Another important asset is the segregation coefficient of Mn in CdTe that is approximately unity compared to 1.35 for Zn in CdZnTe, so ensuring the homogenous distribution of Mn throughout the ingot; hence, a large-volume stoichiometric yield is attained. However, some materials issues primarily related to the growth process impede the production of large, defect-free single crystals. The high bond-ionicity of CdMnTe entails a higher propensity to crystallize into a hexagonal structure rather than to adopt the expected zinc-blend structure, which is likely to generate twins in the crystals. In addition, bulk defects generate in the as-grown crystals due to the dearth of high-purity Mn, which yields a low-resistivity material. In this presentation, we report on our observations of such material defects in current CdMnTe materials, and our evaluation of its potential as an alternative detector material to the well-known CdZnTe detectors. We characterized the bulk defects of several indium- and vanadium-doped Cd1-xMnxTe crystals by using several advanced techniques, viz., micro-scale mapping, white-beam x-ray diffraction/reflection topography, and chemical etching. Thereafter, we fabricated some detectors from selected CdMnTe crystals, characterized their electrical properties, and tested their performance as room-temperature X- and gamma-ray detectors. Our experimental results indicate that CdMnTe materials could well prove to become a viable alternative in the near future.

  14. Materials and coatings to resist high temperature oxidation and corrosion

    International Nuclear Information System (INIS)

    1977-01-01

    Object of the given papers are the oxidation and corrosion behaviour of several materials (such as stainless steels, iron-, or nickel-, or cobalt-base alloys, Si-based ceramics) used at high temperatures and various investigations on high-temperature protective coatings. (IHoe) [de

  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. Investigation of Breakpoint and Trend of Daily Air Temperature Range for Mashhad, Iran

    Directory of Open Access Journals (Sweden)

    shideh shams

    2017-01-01

    Full Text Available Introduction: Air temperature as an important climatic factor can influence variability and distribution of other climatic parameters. Therefore, tracking the changes in air temperature is a popular procedure in climate change studies.. According to the national academy in the last decade, global temperature has raised 0.4 to 0.8⁰C. Instrumental records show that, with the exception of 1998, the 10 warmest year (during the last 150 years, occurred since 2000, and 2014 was the warmest year. Investigation of maximum and minimum air temperature temporal trend indicates that these two parameters behave differently over time. It has been shown that the minimum air temperature raises noticeably more than the maximum air temperature, which causes a reduction in the difference of maximum and minimum daily air temperature (daily temperature range, DTR. There are several factors that have an influence on reducing DTR such as: Urban development, farms’ irrigation and desertification. It has been shown that DTR reduction occurs mostly during winter and is less frequent during summer, which shows the season’s effect on the temperature trend. Considering the significant effects of the climatological factors on economic and agricultural management issues, the aim of this study is to investigate daily air temperature range for yearly, seasonal and monthly time scales, using available statistical methods. Materials and Methods: Daily maximum and minimum air temperature records (from 1950 to 2010 were obtained from Mashhad Meteorological Organization. In order to control the quality of daily Tmax and Tmin data, four different types of quality controls were applied. First of all, gross errors were checked. In this step maximum and minimum air temperature data exceeding unlikely air temperature values, were eliminated from data series. Second, data tolerance was checked by searching for periods longer than a certain number of consecutive days with exactly the

  17. The use of lightweight aggregate saturated with PCM as a temperature stabilizing material for road surfaces

    International Nuclear Information System (INIS)

    Ryms, Michał; Lewandowski, Witold M.; Klugmann-Radziemska, Ewa; Denda, Hubert; Wcisło, Patrycja

    2015-01-01

    This paper presents the possibility of adding lightweight building aggregates to increase the stability – mechanical as well as thermal – of constructions and road objects. This stability can be achieved through saturating the porous granules of aggregate with a phase-change material (PCM) that allows the accumulation of solar heat. Intense solar radiation, especially during the summer, can cause the asphalt on road surfaces, bridges and parking lots to melt, thus protecting the structure from further overheating. The absence of asphalt layers results in thermal stress and strain conditions causes accelerated wear of road surface. Lightweight aggregate, previously used to reduce the weight of the structures, while maintaining the bearing capacity similar to that offered by conventional concrete structures, thereby gains a new functionality, as a temperature stabilizing material. The paper contains a review of several phase-change materials as well as a study justifying the choice of ceresin, a product of crude oil distillation, as a suitable material for such applications. Information about the aggregate and its possible applications, and a proposed method of saturating the aggregate with ceresin has also been collected and presented. With the help of quantitative research conducted through the use of differential scanning calorimetry, the characteristic of thermodynamic parameters of pure ceresin and expanded clay aggregate (Pollytag) saturated with ceresin was determined. Simulation tests conducted under real conditions on two asphalt surfaces (0.32 × 0.22 × 0.15 m), one of which contained the PCM while the other did not, have shown that even a small addition of ceresin (3% mass relative to the weight of the ground) causes a reduction in surface temperature of about 5 K within the tested temperature range of 318.15–338.15 K. - Highlights: • Road surface overheating on summer days may reach up to 344 K. • Solution against overheating through

  18. Effects of irradiation temperature on polarisation and relaxation characteristics of polymeric materials

    Energy Technology Data Exchange (ETDEWEB)

    Bornstein, Marcel; Dutz, Hartmut; Goertz, Stefan; Reeve, Scott; Runkel, Stefan [Physikalisches Institut, Bonn Univ. (Germany)

    2016-07-01

    To achieve significant enhancement of polarisation of solid target materials one must use the principles of dynamic nuclear polarisation and utilise the coupling of the nuclear and electron spins. The unpaired electrons needed can be created as paramagnetic structural defects by irradiation of the material. Polyethylene and polypropylene materials were irradiated at various temperatures and subsequently polarised with microwaves of approximately 70 GHz at temperatures around 1 K. Additionally the samples were investigated with respect to the nature of the created paramagnetic defects using a X-band EPR spectrometer. It was found that the irradiation temperature has a significant effect on the polarisation values achieved and also on the relaxation times of the materials in the 2.5 T magnetic field. The EPR line shape is clearly dominated by the well known alkyl radical structure.

  19. 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.

  20. Temperature dependence of the Schottky-barrier heights of n-type semiconductors in the temperature range of 7 to 300 K

    International Nuclear Information System (INIS)

    Chen, T.P.; Lee, T.C.; Fung, S.; Beling, C.D.

    1994-01-01

    In this note we present the results of the temperature dependence of the SBH in Au/n-Si, Ag/n-GaAs, and Au/n-GaAs in the temperature range of 7 to 300 K from our internal photoemission measurements. (orig.)

  1. Mechanical properties and dependence with temperature of tetragonal polycrystalline zirconia materials

    International Nuclear Information System (INIS)

    Orange, G.

    1986-01-01

    Polycrystalline zirconia materials with a high content of metastable tetragonal phase have been obtained by pressureless sintering from experimental powders. Mechanical properties have been determined at room temperature and compared with similar materials. The fracture strength (σ /SUB f/ ) and fracture toughness (K /SUB 1c/ ) temperature dependence has been studied, in air environment up to 1000 0 C. Microstructure was studied by SEM examinations of fracture faces and TEM observations. Fracture toughness (of about 10 MPa √m at room temperature) decreases from 200 0 C to 800 0 C. The critical temperature (T /SUB c/ ) is estimated at 600 0 C. We observe an important decreases of fracture strength at 200 0 C. These mechanical properties are discussed on the basis of the stability of the tetragonal phase depending on additive content, grain size and temperature

  2. Two-phase materials for high-temperature service

    CSIR Research Space (South Africa)

    Nabarro, FRN

    2000-09-01

    Full Text Available load is carried by the g phase, which is a ductile material; at high temperatures the g phase is weak, and 0966-9795/00/$ - see front matter #2000 Elsevier Science Ltd. All rights reserved. PII: S0966-9795(00)00030-3 Intermetallics 8 (2000) 979?985 www...-temperature phase of ZrO2 containing 4.5 mol% per cent Y2O3 has the cubic ?uorite structure. A 980 F.R.N. Nabarro / Intermetallics 8 (2000) 979?985 face-centred cube of Zr atoms, with 4 Zr atoms in the unit cell, contains a simple cube of 8 O-atoms. On cooling...

  3. 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.

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

    International Nuclear Information System (INIS)

    Bibik, V; Galeeva, A

    2015-01-01

    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. (paper)

  5. Strategies for Lowering Solid Oxide Fuel Cells Operating Temperature

    Directory of Open Access Journals (Sweden)

    Albert Tarancón

    2009-11-01

    Full Text Available Lowering the operating temperature of solid oxide fuel cells (SOFCs to the intermediate range (500–700 ºC has become one of the main SOFC research goals. High operating temperatures put numerous requirements on materials selection and on secondary units, limiting the commercial development of SOFCs. The present review first focuses on the main effects of reducing the operating temperature in terms of materials stability, thermo-mechanical mismatch, thermal management and efficiency. After a brief survey of the state-of-the-art materials for SOFCs, attention is focused on emerging oxide-ionic conductors with high conductivity in the intermediate range of temperatures with an introductory section on materials technology for reducing the electrolyte thickness. Finally, recent advances in cathode materials based on layered mixed ionic-electronic conductors are highlighted because the decreasing temperature converts the cathode into the major source of electrical losses for the whole SOFC system. It is concluded that the introduction of alternative materials that would enable solid oxide fuel cells to operate in the intermediate range of temperatures would have a major impact on the commercialization of fuel cell technology.

  6. Applications of the KKR-DCA: A Finite-Temperature Density Functional Theory to Predict Chemical Short-Range Order Effects in Disordered Metallic Alloys

    Science.gov (United States)

    Biava, D. A.; Johnson, D. D.

    2009-03-01

    Short-range order (SRO) is ubiquitous in metallic alloys, affecting changes in their electronic, thermodynamic, mechanical, magnetic, and structural properties. For example, SRO is responsible for the yield-strength anomalies observed in Cu-Al at high temperatures, i.e., the materials is more resistant to dislocation motion at high temperature than it is at room temperature. Within the Korringa-Kohn-Rostorker (KKR) electronic-structure method, we present results using the dynamical cluster approximations (DCA) to obtain the temperature-dependent SRO in disordered alloys. We obtain the KKR-DCA SRO energetics versus local neighbor SRO parameters and minimize it at fixed temperature to predict the SRO. We show that the calculated SRO at fixed temperature compares well with available experimental results, and then correlate the results to the electronic structure. We discuss how an accurate analytic estimate can be made for the SRO in most metals due to the dependence of the grand potential on SRO.

  7. New England observed and predicted August stream/river temperature daily range points

    Data.gov (United States)

    U.S. Environmental Protection Agency — The shapefile contains points with associated observed and predicted August stream/river temperature daily ranges in New England based on a spatial statistical...

  8. Giant elastocaloric effect covering wide temperature range in columnar-grained Cu71.5Al17.5Mn11 shape memory alloy

    Directory of Open Access Journals (Sweden)

    Sheng Xu

    2016-10-01

    Full Text Available The elastocaloric effect in a columnar-grained Cu71.5Al17.5Mn11 shape memory alloy fabricated by directional solidification was investigated. A large entropy change of 25.0 J/kg K generated by the reversible martensitic transformation was demonstrated. The adiabatic temperature change of 12-13 K was directly measured, covering a wide temperature range of more than 100 K. The low applied stress with a specific elastocaloric ability of 100.8 K/GPa was identified and the potentially attainable operational temperature window as wide as more than 215 K was also discussed. The outstanding elastocaloric refrigeration capability, together with the low applying stress and uniform phase transformation, makes the columnar-grained Cu–Al–Mn shape memory alloy a promising material for solid-state refrigeration.

  9. Thermal stability of a highly-deformed warm-rolled tungsten plate in the temperature range 1100 °C to 1250 °C

    DEFF Research Database (Denmark)

    Alfonso Lopez, Angel; Juul Jensen, Dorte; Luo, G.-N.

    2015-01-01

    plastic strain by 90% thickness reduction was investigated by isothermal annealing for up to 190 h in the temperature range between 1100 °C and 1250 °C. Vickers hardness testing allowed tracking the changes in mechanical properties caused by recovery and recrystallization. The hardness evolution could......Pure tungsten is considered as armor material for the most critical parts of fusion reactors (i.e. the divertor and the first wall), among other reasons due to its high melting point (3422 °C) and recrystallization temperature. The thermal stability of a pure tungsten plate warm-rolled to a high...... suggest that large plastic deformations (e.g. applied during shaping) are only suitable to produce tungsten components to be used at relatively low temperatures (up to 900 °C for a 2 years lifespan). Higher operation temperatures will lead to fast degradation of the microstructure during operation....

  10. Constitutive modeling of polycarbonate over a wide range of strain rates and temperatures

    Science.gov (United States)

    Wang, Haitao; Zhou, Huamin; Huang, Zhigao; Zhang, Yun; Zhao, Xiaoxuan

    2017-02-01

    The mechanical behavior of polycarbonate was experimentally investigated over a wide range of strain rates (10^{-4} to 5× 103 s^{-1}) and temperatures (293 to 353 K). Compression tests under these conditions were performed using a SHIMADZU universal testing machine and a split Hopkinson pressure bar. Falling weight impact testing was carried out on an Instron Dynatup 9200 drop tower system. The rate- and temperature-dependent deformation behavior of polycarbonate was discussed in detail. Dynamic mechanical analysis (DMA) tests were utilized to observe the glass (α ) transition and the secondary (β ) transition of polycarbonate. The DMA results indicate that the α and β transitions have a dramatic influence on the mechanical behavior of polycarbonate. The decompose/shift/reconstruct (DSR) method was utilized to decompose the storage modulus into the α and β components and extrapolate the entire modulus, the α-component modulus and the β-component modulus. Based on three previous models, namely, Mulliken-Boyce, G'Sell-Jonas and DSGZ, an adiabatic model is proposed to predict the mechanical behavior of polycarbonate. The model considers the contributions of both the α and β transitions to the mechanical behavior, and it has been implemented in ABAQUS/Explicit through a user material subroutine VUMAT. The model predictions are proven to essentially coincide with the experimental results during compression testing and falling weight impact testing.

  11. 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.

  12. Low-temperature mechanical properties of superconducting radio frequency cavity materials

    Science.gov (United States)

    Byun, Thak Sang; Kim, Sang-Ho; Mammosser, John

    2009-08-01

    Low-temperature mechanical behaviors have been investigated for the constituent materials of superconducting radio frequency cavities. Test materials consist of small grain Nb, single crystal Nb, large grain Nb (bicrystal), Ti45Nb-Nb weld joint (e-beam welded), and Ti-316L bimetal joint (explosion welded). The strength of all test metals displayed strong temperature dependence and the Ti-316L bimetal showed the highest strength and lowest ductility among the test materials. The fracture toughness of the small grain Nb metals decreased with decreasing test temperature and reached the lower shelf values (30-40 MPa √m) at or above 173 K. The Ti45Nb base and Ti45Nb-Nb weld metals showed much higher fracture toughness than the small grain Nb. An extrapolation and comparison with existing data showed that the fracture toughness of the small grain Nb metals at 4 K was expected to be similar to those at 173 and 77 K. The results from optical photography at a low magnification and fractography by a scanning electron microscope were consistent with corresponding mechanical properties.

  13. Low-temperature mechanical properties of superconducting radio frequency cavity materials

    Energy Technology Data Exchange (ETDEWEB)

    Byun, Thak Sang [ORNL; Kim, Sang-Ho [ORNL; Mammosser, John [ORNL

    2009-01-01

    Low temperature mechanical behaviors have been investigated for the constituent materials of superconducting radio frequency cavities. Test materials consist of small grain Nb, single crystal Nb, large grain Nb (bicrystal), Ti45Nb-Nb weld joint (e-beam welded), and Ti-316L bimetal joint (explosion welded). The strength of all test metals displayed strong temperature dependence and the Ti-316L bimetal showed the highest strength and lowest ductility among the test materials. The fracture toughness of the small grain Nb metals decreased with decreasing test temperature and reached the lower shelf values (30 40 MPa m) at or above 173 K. The Ti45Nb base and Ti45Nb-Nb weld metals showed much higher fracture toughness than the small grain Nb. An extrapolation and comparison with existing data showed that the fracture toughness of the small grain Nb metals at 4 K was expected to be similar to those at 173 K and 77 K. The results from optical photography at a low magnification and fractography by a scanning electron microscope were consistent with corresponding mechanical properties.

  14. Conduit for high temperature transfer of molten semiconductor crystalline material

    Science.gov (United States)

    Fiegl, George (Inventor); Torbet, Walter (Inventor)

    1983-01-01

    A conduit for high temperature transfer of molten semiconductor crystalline material consists of a composite structure incorporating a quartz transfer tube as the innermost member, with an outer thermally insulating layer designed to serve the dual purposes of minimizing heat losses from the quartz tube and maintaining mechanical strength and rigidity of the conduit at the elevated temperatures encountered. The composite structure ensures that the molten semiconductor material only comes in contact with a material (quartz) with which it is compatible, while the outer layer structure reinforces the quartz tube, which becomes somewhat soft at molten semiconductor temperatures. To further aid in preventing cooling of the molten semiconductor, a distributed, electric resistance heater is in contact with the surface of the quartz tube over most of its length. The quartz tube has short end portions which extend through the surface of the semiconductor melt and which are lef bare of the thermal insulation. The heater is designed to provide an increased heat input per unit area in the region adjacent these end portions.

  15. Materials for high-temperature hydrogen fluorine environments. Final report, June 1976-December 1978

    International Nuclear Information System (INIS)

    Holcombe, C.E. Jr.; Kovach, L.

    1981-03-01

    A determination has been made of the stability of 35 materials under high-temperature, fluorine rich, hydrogen fluoride torch testing. Refractory materials tested included 4 borides, 3 carbides, 3 nitrides, 12 oxides, 1 oxynitride, 1 sulfide, 10 metals, and carbon (10 types). Three materials distinctly performed better than nickel: lanthanum hexaboride, calcium hexaboride, and lanthanum silicon oxynitride. Of these, lanthanum hexaboride is the best candidate tested since it has an estimated upper use temperature > 1726 K, which is above the melting point and more than 300 K above the upper use temperature of nickel

  16. Materials for high-temperature hydrogen fluorine environments. Final report, June 1976-December 1978

    Energy Technology Data Exchange (ETDEWEB)

    Holcombe, C.E. Jr.; Kovach, L.

    1981-03-01

    A determination has been made of the stability of 35 materials under high-temperature, fluorine rich, hydrogen fluoride torch testing. Refractory materials tested included 4 borides, 3 carbides, 3 nitrides, 12 oxides, 1 oxynitride, 1 sulfide, 10 metals, and carbon (10 types). Three materials distinctly performed better than nickel: lanthanum hexaboride, calcium hexaboride, and lanthanum silicon oxynitride. Of these, lanthanum hexaboride is the best candidate tested since it has an estimated upper use temperature > 1726 K, which is above the melting point and more than 300 K above the upper use temperature of nickel.

  17. New England observed and predicted July stream/river temperature daily range points

    Data.gov (United States)

    U.S. Environmental Protection Agency — The shapefile contains points with associated observed and predicted July stream/river temperature daily ranges in New England based on a spatial statistical network...

  18. Creep behavior of materials for high-temperature reactor application

    International Nuclear Information System (INIS)

    Schneider, K.; Hartnagel, W.; Iischner, B.; Schepp, P.

    1984-01-01

    Materials for high-temperature gas-cooled reactor (HTGR) application are selected according to their creep behavior. For two alloys--Incoloy-800 used for the live steam tubing of the thorium high-temperature reactor and Inconel-617 evaluated for tubings in advanced HTGRs--creep curves are measured and described by equations. A microstructural interpretation is given. An essential result is that nonstable microstructures determine the creep behavior

  19. Temperature- and light-responsive smart polymer materials.

    Science.gov (United States)

    Jochum, Florian D; Theato, Patrick

    2013-09-07

    Stimuli-responsive polymers have been attracting great interest within the scientific community for several decades. The unique feature to respond to small changes in the environmental conditions has made this class of materials very promising for several applications in the field of nanoscience, nanotechnology and nanomedicine. So far, several different chemical, physical or biochemical stimuli have been investigated within natural or synthetic polymers. Very interesting and appealing seems to be the combination of several stimuli to tune the properties of these materials in manifold ways. Within this present review, we want to highlight the recent progress in the field of synthetic stimuli-responsive polymers combining temperature and light responsiveness.

  20. Brittle fracture tests at low temperature for transport cask materials

    International Nuclear Information System (INIS)

    Kosaki, Akio; Ito, Chihiro; Arai, Taku; Saegusa, Toshiari

    1993-01-01

    The IAEA Regulations for the Safe Transport of Radioactive Material were revised in 1985, and brittle fracture assessment at low temperature for transport packages are now required. This report discusses the applicability of the actual method for brittle fracture assessment of type-B transport cask materials used in JAPAN. The necessity of brittle fracture assessment at low temperature was estimated for each material of type-B transport casks used in Japan and the applicability was investigated. Dynamic fracture toughness values, K Id (J Id ), and RT NDT values of Low-Mn Carbon Steels, that are SA 350 Gr.LF1 Modify and SA 516 Gr.70 material which used in type-B transport cask body, were also obtained to check whether or not an easier and conventional test method, that prescribed in ASME CODE SECTION III, can be substituted for the dynamic fracture test method. And for bolt materials, which include 1.8Ni-0.8Cr-0.3Mo Carbon Steel and type 630 H Stainless Steel, toughness data were obtained for reference. (J.P.N.)

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

    International Nuclear Information System (INIS)

    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

  2. Manufacturing Demonstration Facility: Low Temperature Materials Synthesis

    International Nuclear Information System (INIS)

    Graham, David E.; Moon, Ji-Won; Armstrong, Beth L.; Datskos, Panos G.; Duty, Chad E.; Gresback, Ryan; Ivanov, Ilia N.; Jacobs, Christopher B.; Jellison, Gerald Earle; Jang, Gyoung Gug; Joshi, Pooran C.; Jung, Hyunsung; Meyer, Harry M.; Phelps, Tommy

    2015-01-01

    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.

  3. 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.

  4. Transient thermal stresses in multiple connected region exhibiting temperature dependence of material properties

    International Nuclear Information System (INIS)

    Sugano, Yoshihiro; Maekawa, Toshiya.

    1983-01-01

    The examples of the analysis of thermal stress in multiple connection regions such as heat exchangers, nuclear reactor cores, ingot cases and polygonal region with elliptic holes are not few, but the temperature dependence of material constants was neglected in these researches because of the difficulty of analysis though the industrial problems related to thermal stress are apt to occur in the condition of relatively large temperature gradient. Also, the analysis of heat conduction problems taking the temperature dependence of material constants into account was limited to one-dimensional problems for which Kirchhoff's transmission can be used. The purpose of this study is to derive the equation of condition which assures the one-value property of rotation and displacement, taking the temperature dependence of material constants into account, and to complete the formulation of the plane thermal stress problems in multiple connection regions by stress function method. Also the method of numerical analysis using difference method is shown to examine the effectiveness of various formulated equations and the effect of the temperature dependence of material constants on temperature and thermal stress. The example of numerical calculation on a thin rectangular plate with a rectangular hole is shown. (Kako, I.)

  5. Temperature impact on cementitious materials carbonation - description of water transport influence

    International Nuclear Information System (INIS)

    Drouet, E.

    2010-11-01

    Carbonation is the major cause of degradation of reinforced concrete structures. It leads to rebar corrosion and cracking of the concrete cover. In the framework of radioactive waste management, cement-based materials used as building material for structures or containers would be simultaneously submitted to heating (due to the waste thermal output), subsequent drying and atmospheric carbon dioxide. Such environmental conditions are expected to modify the carbonation mechanisms (with respect to temperature). In order to describe their long-term evolution of material, a double approach was developed, combining the description of carbonation and drying for temperatures up to 80 C to complement available data at ambient temperature. The present work focuses on the durability study of four hardened cement pastes; two of them are derived from the reference formulations selected by Andra (CEM I and CEM V) and a low-pH mix. The first experimental campaign focuses on moisture transfer. The effect of temperature on drying is investigated through water vapour desorption experiments. The first desorption isotherms of four hardened cement pastes was characterized at 20, 50 and 80 C. The results show a significant influence of the temperature. For a given relative humidity (RH) the water content equilibrium is always reduced temperature is increased and the starting point of capillary condensation is shifted towards higher RHs. The experimental campaign is complemented through modelling activities. The impact of temperature on the first desorption isotherms is effectively described using the Clausius-Clapeyron equation (characterization of the isosteric heat of adsorption). The intrinsic permeability to water is evaluated through inverse analysis by reprocessing the experimental weight loss of initially saturated samples submitted to constant environmental conditions. The intrinsic permeability appears to increase with temperature in relation to the observed microstructure

  6. Comparison of physically based constitutive models characterizing armor steel over wide temperature and strain rate ranges

    International Nuclear Information System (INIS)

    Xu, Zejian; Huang, Fenglei

    2012-01-01

    Both descriptive and predictive capabilities of five physically based constitutive models (PB, NNL, ZA, VA, and RK) are investigated and compared systematically, in characterizing plastic behavior of the 603 steel at temperatures ranging from 288 to 873 K, and strain rates ranging from 0.001 to 4500 s −1 . Determination of the constitutive parameters is introduced in detail for each model. Validities of the established models are checked by strain rate jump tests performed under different loading conditions. The results show that the RK and NNL models have better performance in the description of material behavior, especially the work-hardening effect, while the PB and VA models predict better. The inconsistency that is observed between the capabilities of description and prediction of the models indicates the existence of the minimum number of required fitting data, reflecting the degree of a model's requirement for basic data in parameter calibration. It is also found that the description capability of a model is dependent to a large extent on both its form and the number of its constitutive parameters, while the precision of prediction relies largely on the performance of description. In the selection of constitutive models, the experimental data and the constitutive models should be considered synthetically to obtain a better efficiency in material behavior characterization

  7. 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.

  8. Forgings made of austenitic chromium-nickel steels for the low temperature range

    International Nuclear Information System (INIS)

    Gruendler, O.; Schwarz, W.; Koren, M.

    1981-01-01

    The authors discuss the low temperature application of austenitic chromium-nickel steels for energy production and process techniques. Material requirements are presented, and the behaviour, mechanical and physical properties of such steels are discussed. The manufacture of forgings is considered and test results presented. (Auth.)

  9. Forgings made of austenitic chromium-nickel steels for the low temperature range

    Energy Technology Data Exchange (ETDEWEB)

    Gruendler, O.; Schwarz, W.; Koren, M. (Vereinigte Edelstahlwerke A.G. (VEW), Kapfenberg (Austria))

    1981-09-01

    The authors discuss the low temperature application of austenitic chromium-nickel steels for energy production and process techniques. Material requirements are presented, and the behaviour, mechanical and physical properties of such steels are discussed. The manufacture of forgings is considered and test results presented.

  10. 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

  11. Study of deuterium retention in/release from ITER-relevant Be-containing mixed material layers implanted at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Sugiyama, K., E-mail: kazuyoshi.sugiyama@ipp.mpg.de [Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-85748 Garching (Germany); Porosnicu, C. [National Institute for Laser, Plasma and Radiation Physics, EURATOM-MEdC Association, 077125 Bucharest (Romania); Jacob, W.; Roth, J.; Dürbeck, Th. [Max-Planck-Institut für Plasmaphysik, EURATOM Association, D-85748 Garching (Germany); Jepu, I.; Lungu, C.P. [National Institute for Laser, Plasma and Radiation Physics, EURATOM-MEdC Association, 077125 Bucharest (Romania)

    2013-07-15

    D implantation into Be-containing mixed material layers: Be, Be–W (W: ∼6 at.%) and Be–C (C: ∼50 at.%), was performed at elevated temperatures. The temperature dependence of D retention varied depending on the admixed element. D retention in Be and Be–W layers decreases with increasing implantation temperature, while the Be–C layers maintained rather high D retention in the present investigated temperature range (up to 623 K). D desorption behaviour from Be–C suggests the contribution of C–D bonds to D retention. W admixture into Be can significantly suppress D retention in Be. Long-term isothermal annealing at 513 and 623 K for D removal was also performed to simulate the ITER-wall-baking scenario. Even extended annealing at temperatures comparable to or lower than the implantation temperature does not lead to a significant release of retained D.

  12. ASM Inaugural Lecture 2009: High temperature superconductors: Materials, mechanisms and applications

    International Nuclear Information System (INIS)

    Roslan Abdul Shukor

    2009-01-01

    A surprising variety of new superconducting materials has been discovered in recent years. Many compounds with light elements such as fullerenes, oxides, borides, nitrides, some organic materials and also heavy fermions have been found to superconductor at various temperatures. Hitherto, superconductors have proven to be highly varied in composition but elusive and mysterious. The juxtaposition of superconductivity and magnetism at the nano scale in some of these new materials has paved the way to a rich and exciting new field in condensed matter and materials research. An overview of superconductor research in Malaysian institutions is presented in this paper. Some of the new superconducting materials and their possible mechanisms, conventional and exotic, are presented. The possible role of lattice vibrations in the mechanisms of high temperature superconductivity and the study of this via acoustic methods are discussed. Frozen flux superconductors in a nano magnet-superconductor hybrid system are also discussed. (author)

  13. Reaction rate constants of HO2 + O3 in the temperature range 233-400 K

    Science.gov (United States)

    Wang, Xiuyan; Suto, Masako; Lee, L. C.

    1988-01-01

    The reaction rate constants of HO2 + O3 were measured in the temperature range 233-400 K using a discharge flow system with photofragment emission detection. In the range 233-253 K, the constants are approximately a constant value, and then increase with increasing temperature. This result suggests that the reaction may have two different channels. An expression representing the reaction rate constants is presented.

  14. Modelling of the high temperature behaviour of metallic materials

    International Nuclear Information System (INIS)

    Mohr, R.

    1999-01-01

    The design of components of metallic high-temperature materials by the finite element method requires the application of phenomenological viscoplastic material models. The route from the choice of a convenient model, the numerical integration of the equations and the parameter identification to the design of components is described. The Chaboche-model is used whose evolution equations are explicitly integrated. The parameters are determined by graphical and numerical methods in order to use the material model for describing the deformation behaviour of a chromium steel and an intermetallic titanium aluminide alloy. (orig.)

  15. Salinity/temperature ranges for application of seawater SA-T-P models

    Science.gov (United States)

    Marion, G. M.; Millero, F. J.; Feistel, R.

    2009-01-01

    At the present time, little is known about how broad salinity and temperature ranges are for seawater thermodynamic models that are functions of absolute salinity (SA), temperature (T) and pressure (P). Such models rely on fixed compositional ratios of the major components (e.g. Na/Cl, Mg/Cl, Ca/Cl, SO4/Cl, etc.). As seawater evaporates or freezes, solid phases (e.g. CaCO3(s) or CaSO42H2O(s)) will eventually precipitate. This will change the compositional ratios, and these salinity models will no longer be applicable. A future complicating factor is the lowering of seawater pH as the atmospheric concentrations of CO2 increase. A geochemical model (FREZCHEM) was used to quantify the SA-T boundaries at P=0.1 MPa and the range of these boundaries for future atmospheric CO2 increases. An omega supersaturation model for CaCO3 minerals based on homogeneous nucleation was extended from 25-40°C to 3°C. CaCO3 minerals were the boundary defining minerals (first to precipitate) between 3°C (at SA=104 g kg-1 and 40°C (at SA=66 g kg-1. At 2.82°C, calcite(CaCO3) transitioned to ikaite(CaCO36H2O) as the dominant boundary defining mineral for colder temperatures, which culminated in a low temperature boundary of -4.93°C. Increasing atmospheric CO2 from 385 μatm (in Year 2008) to 550 μatm (in Year 2100) would increase the SA and t boundaries as much as 11 g kg-1 and 0.66°C, respectively. The model-calculated calcite-ikaite transition temperature of 2.82°C is in excellent agreement with ikaite formation in natural environments that occurs at temperatures of 3°C or lower. Furthermore, these results provide a quantitative theoretical explanation (FREZCHEM model calculations) for why ikaite is the solid phase CaCO3 mineral that precipitates during seawater freezing.

  16. Effect of cutoff radius, long range interaction and temperature controller on thermodynamic properties of fluids: Methanol as an example

    Science.gov (United States)

    Obeidat, Abdalla; Jaradat, Adnan; Hamdan, Bushra; Abu-Ghazleh, Hind

    2018-04-01

    The best spherical cutoff radius, long range interaction and temperature controller were determined using surface tension, density, and diffusion coefficients of van Leeuwen and Smit methanol. A quite good range of cutoff radii from 0.75 to 1.45 nm has been studied on Coulomb cut-off and particle mesh Ewald (PME) long range interaction to determine the best cutoff radius and best long range interaction as well for four sets of temperature: 200, 230, 270 and 300 K. To determine the best temperature controller, the cutoff radius of 1.25 nm was fixed using PME long range interaction on calculating the above properties at low temperature range: 200-300 K.

  17. 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.

  18. 1000–ton testing machine for cyclic fatigue tests of materials at liquid nitrogen temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Khitruk, A. A.; Klimchenko, Yu. A.; Kovalchuk, O. A.; Marushin, E. L.; Mednikov, A. A.; Nasluzov, S. N.; Privalova, E. K.; Rodin, I. Yu.; Stepanov, D. B.; Sukhanova, M. V. [The D.V. Efremov Scientific Research Institute of Electrophysical Apparatus (NIIEFA), 3 Doroga na Metallostroy, Metallostroy, Saint Petersburg 196641 (Russian Federation)

    2014-01-29

    One of the main tasks of superconductive magnets R and D is to determine the mechanical and fatigue properties of structural materials and the critical design elements in the cryogenic temperature range. This paper describes a new facility built based on the industrial 1000-ton (10 MN) testing machine Schenk PC10.0S. Special equipment was developed to provide the mechanical and cyclic tensile fatigue tests of large-scale samples at the liquid nitrogen temperature and in a given load range. The main feature of the developed testing machine is the cryostat, in which the device converting a standard compression force of the testing machine to the tensile force affected at the test object is placed. The control system provides the remote control of the test and obtaining, processing and presentation of test data. As an example of the testing machine operation the test program and test results of the cyclic tensile fatigue tests of fullscale helium inlet sample of the PF1 coil ITER are presented.

  19. 1000–ton testing machine for cyclic fatigue tests of materials at liquid nitrogen temperatures

    International Nuclear Information System (INIS)

    Khitruk, A. A.; Klimchenko, Yu. A.; Kovalchuk, O. A.; Marushin, E. L.; Mednikov, A. A.; Nasluzov, S. N.; Privalova, E. K.; Rodin, I. Yu.; Stepanov, D. B.; Sukhanova, M. V.

    2014-01-01

    One of the main tasks of superconductive magnets R and D is to determine the mechanical and fatigue properties of structural materials and the critical design elements in the cryogenic temperature range. This paper describes a new facility built based on the industrial 1000-ton (10 MN) testing machine Schenk PC10.0S. Special equipment was developed to provide the mechanical and cyclic tensile fatigue tests of large-scale samples at the liquid nitrogen temperature and in a given load range. The main feature of the developed testing machine is the cryostat, in which the device converting a standard compression force of the testing machine to the tensile force affected at the test object is placed. The control system provides the remote control of the test and obtaining, processing and presentation of test data. As an example of the testing machine operation the test program and test results of the cyclic tensile fatigue tests of fullscale helium inlet sample of the PF1 coil ITER are presented

  20. 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.

  1. Development and evaluation of high temperature materials for power plant

    International Nuclear Information System (INIS)

    Nickel, H.; Schubert, F.

    1992-01-01

    The development of high temperature materials requires the evaluation of the interaction of microstructure and mechanical properties, the implementation of the microstructural aspects in the constitutive equations for the analysis of loads in a high temperature component and verification of the materials reactions. In this way the full potential of materials properties can be better used. This fundamental method is the basis for the formulation of the structural design code KTA 3221 'Metallic HTR Components'. The method of 'design by analysis' is also activated for large internally cooled turbine blades for stationary gas turbines in combined cycle power plants. This kind of exploratory analysis during the dimensioning procedure are discussed with two examples: He/He-heat exchanger produced of NiCr23Co12Mo (Alloy 617) and turbine blades made of superalloys (e.g. IN 738 LC). (author)

  2. 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...... facility has been established wherein the planned exposures are completed. Specimens were exposed in combined synthetic flue gas at temperatures up to 900C. The specimens could be cooled to 300C below the gas temperature. Gas flow and gas mixture can be varied according to the conditions found in a power......) 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...

  3. The ageing kinetics of CF3 cast stainless steel in the temperature range 3000C to 400OC

    International Nuclear Information System (INIS)

    Akhurst, K.N.; Pumphrey, P.H.

    1988-11-01

    The primary coolant pump casings for Sizewell 'B' are made from castings of ASME SA351 CF3 steel which, although predominantly austenitic, is required to contain a small proportion of ferrite. Previous studies have shown that such steels are susceptible to hardening of the ferrite, and associated losses in toughness, as a result of thermal ageing for long times at the service temperature (∼ 300 0 C). For this reason, toughness tests are to be carried out on representative castings made by the Sizewell 'B' pump casing manufacturer. The purpose of these tests is to demonstrate adequate end-of-life fracture resistance, using material which has been given an accelerated ageing treatment. The identification and validation of a suitable ageing treatment is the subject of this Report. Ageing kinetics have been measured for ageing temperatures in the range 300 to 400 0 C, from the results of Charpy impact tests on material from the castings procured for the main fracture programme. Castings with ferrite levels of 15, 25 and 35% have been studied. The losses in impact toughness have been related to the kinetics of ferrite strengthening using microhardness measurements, and to microstructural changes using Field Ion Atom Probe analysis. (author)

  4. Anisotropic deformation of Zr–2.5Nb pressure tube material at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Fong, R.W.L., E-mail: fongr@aecl.ca [Fuel and Fuel Channel Safety Branch, Atomic Energy of Canada Limited, Chalk River Nuclear Laboratories, Chalk River, Ontario (Canada)

    2013-09-15

    Zr–2.5Nb alloy is used for the pressure tubes in CANDU® reactor fuel channels. In reactor, the pressure tube normally operates at 300 °C and experiences a primary coolant fluid internal pressure of approximately 10 MPa. Manufacturing and processing procedures generate an anisotropic state in the pressure tube which makes the tube stronger in the hoop (transverse) direction than in the axial (longitudinal) direction. This anisotropy condition is present for temperatures less than 500 °C. During postulated accident conditions where the material temperature could reach 1000 °C, it might be assumed that the high temperature and subsequent phase change would reduce the inherent anisotropy, and thus affect the deformation behaviour (ballooning) of the pressure tube. From constant-load, rapid-temperature-ramp, uniaxial deformation tests, the deformation rate in the longitudinal direction of the tube behaves differently than the deformation rate in the transverse direction of the tube. This anisotropic mechanical behaviour appears to persist at temperatures up to 1000 °C. This paper presents the results of high-temperature deformation tests using longitudinal and transverse specimens taken from as-received Zr–2.5Nb pressure tubes. It is shown that the anisotropic deformation behaviour observed at high temperatures is largely due to the stable crystallographic texture of the α-Zr phase constituent in the material that was previously observed by neutron diffraction measurements during heating at temperatures up to 1050 °C. The deformation behaviour is also influenced by the phase transformation occurring at high temperatures during heating. The effects of texture and phase transformation on the anisotropic deformation of as-received Zr–2.5Nb pressure tube material are discussed in the context of the tube ballooning behaviour. Because of the high temperatures in postulated accident scenarios, any irradiation damage will be annealed from the pressure tube material

  5. Electrolytes for Use in High Energy Lithium-ion Batteries with Wide Operating Temperature Range

    Science.gov (United States)

    Smart, Marshall C.; Ratnakumar, B. V.; West, W. C.; Whitcanack, L. D.; Huang, C.; Soler, J.; Krause, F. C.

    2012-01-01

    Met programmatic milestones for program. Demonstrated improved performance with wide operating temperature electrolytes containing ester co-solvents (i.e., methyl butyrate) containing electrolyte additives in A123 prototype cells: Previously demonstrated excellent low temperature performance, including 11C rates at -30 C and the ability to perform well down to -60 C. Excellent cycle life at room temperature has been displayed, with over 5,000 cycles being demonstrated. Good high temperature cycle life performance has also been achieved. Demonstrated improved performance with methyl propionate-containing electrolytes in large capacity prototype cells: Demonstrated the wide operating temperature range capability in large cells (12 Ah), successfully scaling up technology from 0.25 Ah size cells. Demonstrated improved performance at low temperature and good cycle life at 40 C with methyl propionate-based electrolyte containing increasing FEC content and the use of LiBOB as an additive. Utilized three-electrode cells to investigate the electrochemical characteristics of high voltage systems coupled with wide operating temperature range electrolytes: From Tafel polarization measurements on each electrode, it is evident the NMC-based cathode displays poor lithium kinetics (being the limiting electrode). The MB-based formulations containing LiBOB delivered the best rate capability at low temperature, which is attributed to improved cathode kinetics. Whereas, the use of lithium oxalate as an additive lead to the highest reversible capacity and lower irreversible losses.

  6. Evaluation of plastic materials for range shifting, range compensation, and solid-phantom dosimetry in carbon-ion radiotherapy

    International Nuclear Information System (INIS)

    Kanematsu, Nobuyuki; Koba, Yusuke; Ogata, Risa

    2013-01-01

    Purpose: Beam range control is the essence of radiotherapy with heavy charged particles. In conventional broad-beam delivery, fine range adjustment is achieved by insertion of range shifting and compensating materials. In dosimetry, solid phantoms are often used for convenience. These materials should ideally be equivalent to water. In this study, the authors evaluated dosimetric water equivalence of four common plastics, high-density polyethylene (HDPE), polymethyl methacrylate (PMMA), polyethylene terephthalate (PET), and polyoxymethylene (POM). Methods: Using the Bethe formula for energy loss, the Gottschalk formula for multiple scattering, and the Sihver formula for nuclear interactions, the authors calculated the effective densities of the plastics for these interactions. The authors experimentally measured variation of the Bragg peak of carbon-ion beams by insertion of HDPE, PMMA, and POM, which were compared with analytical model calculations. Results: The theoretical calculation resulted in slightly reduced multiple scattering and severely increased nuclear interactions for HDPE, compared to water and the other plastics. The increase in attenuation of carbon ions for 20-cm range shift was experimentally measured to be 8.9% for HDPE, 2.5% for PMMA, and 0.0% for POM while PET was theoretically estimated to be in between PMMA and POM. The agreement between the measurements and the calculations was about 1% or better. Conclusions: For carbon-ion beams, POM was dosimetrically indistinguishable from water and the best of the plastics examined in this study. The poorest was HDPE, which would reduce the Bragg peak by 0.45% per cm range shift, although with marginal superiority for reduced multiple scattering. Between the two clear plastics, PET would be superior to PMMA in dosimetric water equivalence.

  7. The mechanical behavior and reliability prediction of the HTR graphite component at various temperature and neutron dose ranges

    International Nuclear Information System (INIS)

    Fang, Xiang; Yu, Suyuan; Wang, Haitao; Li, Chenfeng

    2014-01-01

    Highlights: • The mechanical behavior of graphite component in HTRs under high temperature and neutron irradiation conditions is simulated. • The computational process of mechanical analysis is introduced. • Deformation, stresses and failure probability of the graphite component are obtained and discussed. • Various temperature and neutron dose ranges are selected in order to investigate the effect of in-core conditions on the results. - Abstract: In a pebble-bed high temperature gas-cooled reactor (HTR), nuclear graphite serves as the main structural material of the side reflectors. The reactor core is made up of a large number of graphite bricks. In the normal operation case of the reactor, the maximum temperature of the helium coolant commonly reaches about 750 °C. After around 30 years’ full power operation, the peak value of in-core fast neutron cumulative dose reaches to 1 × 10 22 n cm −2 (EDN). Such high temperature and neutron irradiation strongly impact the behavior of graphite component, causing obvious deformation. The temperature and neutron dose are unevenly distributed inside a graphite brick, resulting in stress concentrations. The deformation and stress concentration can both greatly affect safety and reliability of the graphite component. In addition, most of the graphite properties (such as Young's modulus and coefficient of thermal expansion) change remarkably under high temperature and neutron irradiations. The irradiation-induced creep also plays a very important role during the whole process, and provides a significant impact on the stress accumulation. In order to simulate the behavior of graphite component under various in-core conditions, all of the above factors must be considered carefully. In this paper, the deformation, stress distribution and failure probability of a side graphite component are studied at various temperature points and neutron dose levels. 400 °C, 500 °C, 600 °C and 750 °C are selected as the

  8. The influence of interstitial impurities on temperature ranges of deuterium retention in austenitic stainless steel 18Cr10NiTi

    International Nuclear Information System (INIS)

    Neklyudov, I.M.; Morozov, O.M.; Kulish, V.G.; Zhurba, V.I.; Galytsky, A.G.; Piatenko, E.V.

    2009-01-01

    The influence of nitrogen, oxygen and helium on the temperature range of deuterium retention in 18Cr10NiTi stainless steel (of AISI304L type) has been investigated. It is demonstrated that the introduction of oxygen, nitrogen or helium into 18Cr10NiTi steel extends the upper limit in the high-temperature range of deuterium retention. It has been found that for 18Cr10NiTi stainless steel, pre-irradiated with helium ions, the increase in the temperature range of deuterium retention occurs in steps: on attainment of helium concentration of ∼0.5 at.% He the temperature range increases by ∼100 K, and on attainment of helium concentration of ∼2.5 at.% He the temperature range increases by ∼350 K. The introduction of oxygen into 18Cr10NiTi stainless steel results in the increase of the temperature range of deuterium retention in the direction of rise in temperature. In the deuterium thermodesorption spectrum, this manifests itself by the occurrence of an additional low-amplitude peak with the maximum temperature T m ∼ 560 K. The introduction of nitric impurity into 18Cr10NiTi stainless steel results in the extension of the temperature range of deuterium retention towards higher temperatures.

  9. Design, Fabrication, Test Report of the Material Capsule(08M-10K) with Double Thermal Media for High-temperature Irradiation

    International Nuclear Information System (INIS)

    Cho, Man Soon; Choo, K. N.; Kang, Y. H.; Sohn, J. M.; Shin, Y. T.; Park, S. J.; Kim, B. G.; Oh, S. Y.

    2010-01-01

    To overcome the restriction of the irradiation test at a high temperature of the existing material capsule with Al thermal media, a capsule suitable for the irradiation at the high temperature was developed and the performance test was undertaken. The 08M-10K capsule was designed and fabricated as that with double thermal media to verify the structural and external integrity in the high-temperature irradiation higher than 500 .deg. C. The thermal performance test was undertaken at the out-pile test facility, and the soundness of the double thermal media was confirmed with the naked eye after disassembling the capsule. Though the temperatures of the specimens reach 500±20 .deg. C as a result maintaining the capsule during 5 hours after setting the specimens temperatures in the target range, the high-temperature thermal media with double structure was confirmed to maintain the soundness. And the specimens and the thermal media were heated to 600 .deg. C for about 3 minutes, but the thermal media were maintained sound. Especially, the Al thermal media were heated for 5 hours in range of 500±20 .deg. C and for 3 minutes at the temperature of 600 .deg. C. However, the thermal media were confirmed to maintain the soundness. Whether a capsule has only Al thermal media or the high-temperature thermal media with double structure, any capsule can be used in the range of 500±20 .deg. C as the result of this experiment maintaining the specimens high-temperature

  10. Specialists' meeting on high temperature metallic materials for application in gas-cooled reactors

    International Nuclear Information System (INIS)

    At the meeting overviews of current programmes for the development of high temperature materials in Japan, F.R. Germany and the United States of America were presented. Some papers were presented dealing with various aspects of microstructural studies, surface reactions and the changes of microstructure and dimensions due mainly to the associated interfacial material transports, protective surface coatings for HTGR and AGR applications. Other topics presented were mechanical properties of materials and also the influence of materials' properties data on design at temperatures in the creep region where time dependent behaviour must be considered

  11. Consideration of materials for aircraft brakes

    Science.gov (United States)

    Peterson, M. B.; Ho, T.-L.

    1974-01-01

    A study has been made of the frictional behavior of several aircraft brake materials using a simple high-temperature Falex-type apparatus. Tests were run at velocities of seven ft/minute; loads to 600 pounds and temperatures to 700 C. The data for these brake materials sliding against a variety of steels and other materials indicate a large reduction in friction due to surface oxidation in the temperature range 250 to 300 C. It also was found that the retention of this oxide was a function of the temperature changes. With increasing temperature the oxide was removed, while with reducing temperature it was retained. Frictional behavior was more characteristic of the steel than the brake material.

  12. Low-temperature plasma spheroidizing of polydisperse powders of refractory materials

    International Nuclear Information System (INIS)

    Tsymbalist, M.M.; Rudenskaya, N.A.; Kuz'min, B.P.; Pan'kov, V.A.

    2003-01-01

    A model is developed for heating and melting of a spherical particle, when powder processing in low temperature plasma, with the aim of estimation of the dependence of the degree of fusion on particle size for various materials. Spheroidizing of various refractory material powders close in shape and size composition is experimentally performed. Experimental and calculation estimates of spheroidizing criteria for the materials studied are in a satisfactory agreement. The influence of basic physical properties of refractory materials and plasma processing parameters on the degree of particle spheroidizing is analyzed [ru

  13. Synthesis and analysis of Mo-Si-B based coatings for high temperature oxidation protection of ceramic materials

    Science.gov (United States)

    Ritt, Patrick J.

    The use of Ni-based superalloys in turbine engines has all but been exhausted, with operating temperatures nearing the melting point of these materials. The use of ceramics in turbine engines, particularly ceramic matrix composites such as SiC/C and SiC/SiC, is of interest due to their low density and attractive mechanical properties at elevated temperatures. The same materials are also in consideration for leading edges on hypersonic vehicles. However, SiC-based composites degrade in high temperature environments with low partial pressures of oxygen due to active oxidation, as well as high temperature environments containing water or sand. The need for a protective external coating for SiC-based composites in service is obvious. To date, no coating investigated for SiC/C or SiC/SiC has been proven to be resistant to oxidation and corrosion at intermediate and high temperatures, as well as in environments deficient in oxygen. The Mo-Si-B coating shows great promise in this area, having been proven resistant to attack from oxidation at extreme temperatures, from water vapor and from calcia-magnesia-aluminosilicate (CMAS). The adaptation of the Mo-Si-B coating for ceramic materials is presented in detail here. Evaluation of the coating under a range of oxidation conditions as well as simulated re-entry conditions confirms the efficacy of the Mo-Si-B based coating as protection from catastrophic failure. The key to the oxidation and corrosion resistance is a robust external aluminoborosilica glass layer that forms and flows quickly to cover the substrate, even under the extreme simulated re-entry conditions. Suppression of active oxidation of SiC, which may occur during atmospheric re-entry and hypersonic flight trajectories, has also been examined. In order to adapt the Mo-Si-B based coating to low partial pressures of oxygen and elevated temperatures, controlled amounts of Al were added to the Mo-Si-B based coating. The resulting coating decreased the inward

  14. Electrolytes for Low Impedance, Wide Operating Temperature Range Lithium-Ion Battery Module

    Science.gov (United States)

    Hallac, Boutros (Inventor); Krause, Frederick C. (Inventor); Jiang, Junwei (Inventor); Smart, Marshall C. (Inventor); Metz, Bernhard M. (Inventor); Bugga, Ratnakumar V. (Inventor)

    2018-01-01

    A lithium ion battery cell includes a housing, a cathode disposed within the housing, wherein the cathode comprises a cathode active material, an anode disposed within the housing, wherein the anode comprises an anode active material, and an electrolyte disposed within the housing and in contact with the cathode and anode. The electrolyte consists essentially of a solvent mixture, a lithium salt in a concentration ranging from approximately 1.0 molar (M) to approximately 1.6 M, and an additive mixture. The solvent mixture includes a cyclic carbonate, an non-cyclic carbonate, and a linear ester. The additive mixture consists essentially of lithium difluoro(oxalato)borate (LiDFOB) in an amount ranging from approximately 0.5 weight percent to approximately 2.0 weight percent based on the weight of the electrolyte, and vinylene carbonate (VC) in an amount ranging from approximately 0.5 weight percent to approximately 2.0 weight percent based on the weight of the electrolyte.

  15. Impact of container material on the development of Aedes aegypti larvae at different temperatures.

    Science.gov (United States)

    Kumar, Gaurav; Singh, R K; Pande, Veena; Dhiman, R C

    2016-01-01

    Aedes aegypti, the primary vector of dengue generally breeds in intradomestic and peridomestic containers made up of different materials, i.e. plastic, iron, rubber, earthen material etc. The material of container is likely to affect the temperature of water in container with variation in environmental temperature. The present study was aimed to determine the effect of different container materials on larval development of Ae. aegypti at different temperatures. Newly hatched I instar larvae (2-4 h old) were used in the study and experiments were conducted using three different containers made up of plastic, iron and earthen material. Three replicates for each type of container at 22, 26, 30, 34, 38, 40, and 42°C were placed in environmental chamber for the development of larvae. At temperatures >22°C, 50% pupation was completed in earthen pot within 4.3±0.6 to 6.3±0.6 days followed by plastic containers (5±0 to 8±0 days) and iron containers (6±0 to 9±0 days). Developmental time for 50% pupation in the three containers differed significantly (p containers (p containers resulted in significant variations in the developmental period of larvae. More than 35°C temperature of water was found inimical for pupal development. The results revealed the variation in temperature of water in different types of containers depending on the material of container, affecting duration of larval development. As the larval development was faster in earthen pot as compared to plastic and iron containers, community should be discouraged for storing the water in earthen pots. However, in view of containers of different materials used by the community in different temperature zones in the country, further studies are required for devising area-specific preventive measures for Aedes breeding.

  16. The dynamical mechanical properties of tungsten under compression at working temperature range of divertors

    Science.gov (United States)

    Zhu, C. C.; Song, Y. T.; Peng, X. B.; Wei, Y. P.; Mao, X.; Li, W. X.; Qian, X. Y.

    2016-02-01

    In the divertor structure of ITER and EAST with mono-block module, tungsten plays not only a role of armor material but also a role of structural material, because electromagnetic (EM) impact will be exerted on tungsten components in VDEs or CQ. The EM loads can reach to 100 MN, which would cause high strain rates. In addition, directly exposed to high-temperature plasma, the temperature regime of divertor components is complex. Aiming at studying dynamical response of tungsten divertors under EM loads, an experiment on tungsten employed in EAST divertors was performed using a Kolsky bar system. The testing strain rates and temperatures is derived from actual working conditions, which makes the constitutive equation concluded by using John-Cook model and testing data very accurate and practical. The work would give a guidance to estimate the dynamical response, fatigue life and damage evolution of tungsten divertor components under EM impact loads.

  17. The temperature dependence of intermediate range oxygen-oxygen correlations in liquid water

    International Nuclear Information System (INIS)

    Schlesinger, Daniel; Pettersson, Lars G. M.; Wikfeldt, K. Thor; Skinner, Lawrie B.; Benmore, Chris J.; Nilsson, Anders

    2016-01-01

    We analyze the recent temperature dependent oxygen-oxygen pair-distribution functions from experimental high-precision x-ray diffraction data of bulk water by Skinner et al. [J. Chem. Phys. 141, 214507 (2014)] with particular focus on the intermediate range where small, but significant, correlations are found out to 17 Å. The second peak in the pair-distribution function at 4.5 Å is connected to tetrahedral coordination and was shown by Skinner et al. to change behavior with temperature below the temperature of minimum isothermal compressibility. Here we show that this is associated also with a peak growing at 11 Å which strongly indicates a collective character of fluctuations leading to the enhanced compressibility at lower temperatures. We note that the peak at ∼13.2 Å exhibits a temperature dependence similar to that of the density with a maximum close to 277 K or 4 °C. We analyze simulations of the TIP4P/2005 water model in the same manner and find excellent agreement between simulations and experiment albeit with a temperature shift of ∼20 K.

  18. The temperature dependence of intermediate range oxygen-oxygen correlations in liquid water

    Energy Technology Data Exchange (ETDEWEB)

    Schlesinger, Daniel; Pettersson, Lars G. M., E-mail: Lars.Pettersson@fysik.su.se [Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm (Sweden); Wikfeldt, K. Thor [Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm (Sweden); Science Institute, University of Iceland, VR-III, 107 Reykjavik (Iceland); Skinner, Lawrie B.; Benmore, Chris J. [X-ray Science Division, Advanced Photon Source, Argonne National Laboratory, Argonne, Illinois 60439 (United States); Nilsson, Anders [Department of Physics, AlbaNova University Center, Stockholm University, SE-106 91 Stockholm (Sweden); Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, Menlo Park, California 94025 (United States)

    2016-08-28

    We analyze the recent temperature dependent oxygen-oxygen pair-distribution functions from experimental high-precision x-ray diffraction data of bulk water by Skinner et al. [J. Chem. Phys. 141, 214507 (2014)] with particular focus on the intermediate range where small, but significant, correlations are found out to 17 Å. The second peak in the pair-distribution function at 4.5 Å is connected to tetrahedral coordination and was shown by Skinner et al. to change behavior with temperature below the temperature of minimum isothermal compressibility. Here we show that this is associated also with a peak growing at 11 Å which strongly indicates a collective character of fluctuations leading to the enhanced compressibility at lower temperatures. We note that the peak at ∼13.2 Å exhibits a temperature dependence similar to that of the density with a maximum close to 277 K or 4 °C. We analyze simulations of the TIP4P/2005 water model in the same manner and find excellent agreement between simulations and experiment albeit with a temperature shift of ∼20 K.

  19. Laser parameters of a Fe : ZnSe crystal in the 85-255-K temperature range

    NARCIS (Netherlands)

    Voronov, AA; Kozlovskii, [No Value; Korostelin, YV; Podmar'kov, YP; Frolov, MP

    The temperature dependence of the efficiency of a laser based on a Fe:ZnSe crystal grown from the vapour phase by the free-growth method is studied in the 85-255-K temperature range. As the temperature was increased, the slope efficiency of the laser with respect to absorbed energy decreased from

  20. Interrelationship betwen material strength and component design under elevated temperature for FBR

    International Nuclear Information System (INIS)

    Nakagawa, Y.

    Structural design under elevated temperature for fast breeder reactor plant is very troublesome compared to that of for lower temperature. This difficulty can be mainly discussed from two different stand points. One is design and design code, another is material strength. Components in FBR are operated under creep regime and time dependent creep behaviour should be elevated properly. This means the number and combinations of design code and material strength are significantly large and makes these systems very complicated. Material selection is, in no words, not an easy job. This should be done by not only material development but also component design stand point. With valuable experience of construction and research on FBR, a lot of information on component design and material behaviour is available. And it is a time to choose the ''best material'' from the entire stand points of component construction. (author)

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

    International Nuclear Information System (INIS)

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

    2004-01-01

    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

  2. Europa Lander Material Selection Considerations

    Energy Technology Data Exchange (ETDEWEB)

    Tappan, Alexander S. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Heller, Mellisa [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-01-10

    Energetic materials (EMs, explosives, pyrotechnics, propellants) provide high-power output of high temperature reaction products. These products can be solid, liquid, or gaseous during reaction or after the products have equilibrated with the surroundings. For example, high explosives typically consist of carbon, hydrogen, nitrogen, and oxygen bonded within a single molecule, and produce almost exclusively gaseous products. Conversely, intermetallics consist of physical mixtures of metals and metalloids, and produce almost exclusively condensed products. Other materials such as pyrotechnics and propellants have intermediate behavior. All energetic materials react in a self-propagating manner that after ignition, does not necessarily require energy input from the surroundings. The range of reaction velocities can range from mm/s for intermetallics, to km/s for high explosives. Energetic material selection depends on numerous requirements specific to the needs of a system. High explosives are used for applications where high pressure gases are necessary for pushing or fracturing materials (e.g., rock, metal) or creating shock waves or air blast. Propellants are used to produce moderate-pressure, high-temperature products without a shock wave. Pyrotechnics are used to produce numerous effects including: high-temperature products, gases, light, smoke, sound, and others. Thermites are used to produce heat, high-temperature products, materials, and other effects that require condensed products. Intermetallics are used to produce high-temperature condensed products and materials, with very little gas production. Numerous categories of energetic materials exist with overlapping definitions, effects, and properties.

  3. Dislocation mechanisms for plastic flow of nickel in the temperature range 4.2-1200K

    International Nuclear Information System (INIS)

    Sastry, D.H.; Tangri, K.

    1975-01-01

    The temperature ranges of thermal and athermal deformation behaviour of nickel are identified by employing the temperature-dependence of flow-stress and strain-rate cycling data. The results are used to present a unified view of dislocation mechanisms of glide encompassing the two thermally activated and the intermediate athermal regimes of plastic flow. In the low-temperature thermally activated region (<250K) the strain rate is found to be controlled by the repulsive intersection of glide and forest dislocations, in accordance with current ideas. The athermal stress in this region can be attributed mainly to the presence of strong attractive junctions which are overcome by means of Orowan bowing, a small contribution also coming from the elastic interactions between dislocations. The values of activation area and activation energy obtained in the high-temperature region (<750K) negate the operation of a diffusion-controlled mechanism. Instead, the data support a thermal activation model involving unzipping of the attractive junctions. The internal (long-range) stress contribution here results solely from the elastic interactions between dislocations. This view concerning the high-temperature plastic flow is further supported by the observation that the Cottrell-Stokes law is obeyed over large strains in the range 750-1200K. (author)

  4. Temperature dependence of thermal properties of Ag8In14Sb55Te23 phase-change memory materials

    International Nuclear Information System (INIS)

    Jiao, Xinbing; Gan, Fuxi; Wei, Jingsong; Xiao, Mufei

    2009-01-01

    The dependence of thermal properties of Ag 8 In 14 Sb 55 Te 23 phase-change memory materials in crystalline and amorphous states on temperature was measured and analyzed. The results show that in the crystalline state, the thermal properties monotonically decrease with the temperature and present obvious crystalline semiconductor characteristics. The heat capacity, thermal diffusivity, and thermal conductivity decrease from 0.35 J/gK, 1.85 mm 2 /s, and 4.0 W/mK at 300 K to 0.025 J/gK, 1.475 mm 2 /s, and 0.25 W/mK at 600 K, respectively. In the amorphous state, while the dependence of thermal properties on temperature does not present significant changes, the materials retain the glass-like thermal characteristics. Within the temperature range from 320 K to 440 K, the heat capacity fluctuates between 0.27 J/gK and 0.075 J/gK, the thermal diffusivity basically maintains at 0.525 mm 2 /s, and the thermal conductivity decreases from 1.02 W/mK at 320 K to 0.2 W/mK at 440 K. Whether in the crystalline or amorphous state, Ag 8 In 14 Sb 55 Te 23 are more thermally active than Ge 2 Sb 2 Te 5 , that is, the Ag 8 In 14 Sb 55 Te 23 composites bear stronger thermal conduction and diffusion than the Ge 2 Sb 2 Te 5 phase-change memory materials. (orig.)

  5. 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...

  6. Temperature scaling in a dense vibrofluidized granular material.

    Science.gov (United States)

    Sunthar, P; Kumaran, V

    1999-08-01

    The leading order "temperature" of a dense two-dimensional granular material fluidized by external vibrations is determined. The grain interactions are characterized by inelastic collisions, but the coefficient of restitution is considered to be close to 1, so that the dissipation of energy during a collision is small compared to the average energy of a particle. An asymptotic solution is obtained where the particles are considered to be elastic in the leading approximation. The velocity distribution is a Maxwell-Boltzmann distribution in the leading approximation. The density profile is determined by solving the momentum balance equation in the vertical direction, where the relation between the pressure and density is provided by the virial equation of state. The temperature is determined by relating the source of energy due to the vibrating surface and the energy dissipation due to inelastic collisions. The predictions of the present analysis show good agreement with simulation results at higher densities where theories for a dilute vibrated granular material, with the pressure-density relation provided by the ideal gas law, are in error.

  7. Temperature-dependent dielectric function of germanium in the UV–vis spectral range: A first-principles study

    International Nuclear Information System (INIS)

    Yang, J.Y.; Liu, L.H.; Tan, J.Y.

    2014-01-01

    The study of temperature dependence of thermophysical parameter dielectric function is key to understanding thermal radiative transfer in high-temperature environments. Limited by self-radiation and thermal oxidation, however, it is difficult to directly measure the high-temperature dielectric function of solids with present experimental technologies. In this work, we implement two first-principles methods, the ab initio molecular dynamics (AIMD) and density functional perturbation theory (DFPT), to study the temperature dependence of dielectric function of germanium (Ge) in the UV–vis spectral range in order to provide data of high-temperature dielectric function for radiative transfer study in high-temperature environments. Both the two methods successfully predict the temperature dependence of dielectric function of Ge. Moreover, the good agreement between the calculated results of the AIMD approach and experimental data at 825 K enables us to predict the high-temperature dielectric function of Ge with the AIMD method in the UV–vis spectral range. - Highlights: • The temperature dependence of dielectric function of germanium (Ge) is investigated with two first-principles methods. • The temperature effect on dielectric function of Ge is discussed. • The high-temperature dielectric function of Ge is predicted

  8. Creep constitutive equations for a 0.5Cr 0.5 Mo 0.25V ferritic steel in the temperature range 565 deg. C-675 deg. C

    International Nuclear Information System (INIS)

    Mustata, R.; Hayhurst, D.R.

    2005-01-01

    A two damage state variable model is used to describe the softening mechanisms, damage initiation and growth for a low alloy ferritic steel 1/2Cr-1/2Mo-1/4V at 565 and 590 deg. C within the Continuum Damage Mechanics framework. The level of complexity of the constitutive equations and the degree of coupling through damage is high and it is difficult to calibrate values of the constitutive constants without recourse to optimisation techniques. A methodology for the analysis of uni-axial experimental data, coupled with a traditional gradient-based optimisation technique, is presented for the unique determination of the constitutive constants. Two sets of experimental data on parent material are used for inversion purposes: at 565 deg. C, c.f. Cane [Cane BJ. Collaborative programme on the corelation of test data for high temperature design of welded steam pipes. Presentation and analysis of the material data. Note No. RD/L/2101N81, March, CEGB Laboratory; 1981]; and, at 590 deg. C, c.f. Miller [Miller DA. Private communication: 'Creep rupture testing of Cr M V pipe steel. ERA Project 63-01-040320009'. Barnwood, Gloucs, UK: British Energy; 2000]. The variation of the constitutive parameters with temperature in the range 565-590 deg. C has been deduced by considering the values of constitutive parameters for the same alloy deduced by Perrin and Hayhurst [Perrin IJ, Hayhurst DR. Creep constitutive equations for a 0.5Cr-0.5Mo-0.25V ferritic steel in the temperature range 600-675 deg. C. J Strain Anal 1996;31:299-314] in the temperature range 620-675 deg. C

  9. Computed temperature profile in materials exposed to gamma radiation

    Energy Technology Data Exchange (ETDEWEB)

    Ping, Tso Chin; Choong, Yap Siew; Seon, Chan Kam

    1987-06-01

    Computed temperature profiles are presented for the materials of lead, steel, concrete and water in curved shells, when they are exposed to gamma radiation. The results are based on the usual simplified theory of thermal conduction with an exponential heat source.

  10. Influence of heat treatment and indenter tip material on depth sensing hardness tests at high temperatures of fusion relevant materials

    International Nuclear Information System (INIS)

    Bredl, Julian; Dany, Manuel; Albinski, Bartlomiej; Schneider, Hans-Christian; Kraft, Oliver

    2015-01-01

    Highlights: • Operation of a custom-made indentation device designed for test temperatures up to 650 °C and a remote handled operation in a Hot Cell. • Instrumented indentation and conventional hardness testing of unirradiated MANET II and EUROFER. • Comparison of diamond and sapphire as indenter tip materials. - Abstract: The instrumented indentation is a suitable method for testing of even small neutron-irradiated specimens. From the continuously recorded indentation depth and the indentation force, it is possible to deduce mechanical parameters of the tested material. In this paper, a brief description of the high temperature device is given and representative results are presented. In the study, unirradiated steels are investigated by instrumented indentation at temperatures up to 500 °C. It is shown that the hardness is highly depending on the testing-temperature and can be correlated to the results of conventional tensile testing experiments. A not negligible influence of the indenter tip material is observed. The results show the functionality of the high-temperature indentation device.

  11. Influence of heat treatment and indenter tip material on depth sensing hardness tests at high temperatures of fusion relevant materials

    Energy Technology Data Exchange (ETDEWEB)

    Bredl, Julian, E-mail: julian.bredl@kit.edu; Dany, Manuel; Albinski, Bartlomiej; Schneider, Hans-Christian; Kraft, Oliver

    2015-10-15

    Highlights: • Operation of a custom-made indentation device designed for test temperatures up to 650 °C and a remote handled operation in a Hot Cell. • Instrumented indentation and conventional hardness testing of unirradiated MANET II and EUROFER. • Comparison of diamond and sapphire as indenter tip materials. - Abstract: The instrumented indentation is a suitable method for testing of even small neutron-irradiated specimens. From the continuously recorded indentation depth and the indentation force, it is possible to deduce mechanical parameters of the tested material. In this paper, a brief description of the high temperature device is given and representative results are presented. In the study, unirradiated steels are investigated by instrumented indentation at temperatures up to 500 °C. It is shown that the hardness is highly depending on the testing-temperature and can be correlated to the results of conventional tensile testing experiments. A not negligible influence of the indenter tip material is observed. The results show the functionality of the high-temperature indentation device.

  12. Time-dependent fracture of materials at elevated temperature for solar thermal power systems

    International Nuclear Information System (INIS)

    Gupta, G.D.

    1979-01-01

    Various Solar Thermal Power Systems are briefly described. The components of solar power systems in which time-dependent fracture problems become important are identified. Typical materials of interest, temperature ranges, and stress states are developed; and the number of cycles during the design life of these systems are indicated. The ASME Code procedures used by designers to predict the life of these components are briefly described. Some of the major problems associated with the use of these ASME procedures in the design of solar components are indicated. Finally, a number of test and development needs are identified which would enable the designers to predict the life of the solar power system components with a reasonable degree of confidence

  13. Dusty plasma in a glow discharge in helium in temperature range of 5–300 K

    Energy Technology Data Exchange (ETDEWEB)

    Samoilov, I. S.; Baev, V. P.; Timofeev, A. V., E-mail: timofeevalvl@gmail.com; Amirov, R. Kh.; Kirillin, A. V.; Nikolaev, V. S.; Bedran, Z. V. [Russian Academy of Sciences, Joint Institute for High Temperatures (Russian Federation)

    2017-03-15

    Dusty plasma structures in glow discharge in helium in the temperature range of 5–300 K are investigated experimentally. We have described the experimental setup that makes it possible to continuously vary the temperature regime. The method for experimental data processing has been described. We have measured interparticle distances in the temperature range of 9–295 K and compared them with the Debye radius. We indicate the ranges of variations in experimental parameters in which plasma–dust structures are formed and various types of their behavior are manifested (rotation, vibrations of structures, formation of vertical linear chains, etc.). The applicability of the Yukawa potential to the description of the structural properties of a dusty plasma in the experimental conditions is discussed.

  14. Innovative use of Distributed Temperature Sensing and Meteorological Data to Understand Thermoregulation of Free-Ranging Howling Monkeys

    Science.gov (United States)

    Suarez, F. I.; Vinyard, C. J.; Williams, S. H.; Hausner, M. B.; Tyler, S. W.; Glander, K.

    2011-12-01

    Temperature fluctuations are a major driver of change in natural habitats and influence the lifestyle of all organisms because temperature impacts molecular, physiological, and behavioral processes. However, there is a lack of understanding on how temperature affects metabolism, behavior, and ecology at the organismal level. Even though physiological responses to temperature fluctuations have been well documented in laboratory conditions, it has been challenging to collect the required environmental data to study thermoregulation of free-ranging mammals such as mantled howling monkeys (Alouatta palliata). Fortunately, recent advances in fiber-optic distributed temperature sensing (DTS) now permit the observation of temperature fields in the environment at scales ranging from millimeters to kilometers. This has opened an exciting opportunity for temperature monitoring at scales that were previously not feasible. This study addresses the main limitations of previous studies of primate behavior by integrating real-time environmental data with the behavior and physiological response of free-ranging primates. In this work, we present preliminary DTS data collected in a natural habitat of howling monkeys. Fiber-optic cables were hung between the ground and an elevation of approximately 15 m within the forest canopy, providing continuous profiles of temperature without any disturbance due to the animals and habitat. These measurements were integrated with conventional meteorological data and with the ambient temperature at the location of the animal, as well as with measurements of primate's subcutaneous and core body temperatures. These data will be utilized to determine how environmental conditions relate to primate behavioral and physiological responses in time and space. The methodologies used in this study provide tools to test theories of physiological thermoregulation of other free-ranging animals.

  15. Combining 2-m temperature nowcasting and short range ensemble forecasting

    Directory of Open Access Journals (Sweden)

    A. Kann

    2011-12-01

    Full Text Available During recent years, numerical ensemble prediction systems have become an important tool for estimating the uncertainties of dynamical and physical processes as represented in numerical weather models. The latest generation of limited area ensemble prediction systems (LAM-EPSs allows for probabilistic forecasts at high resolution in both space and time. However, these systems still suffer from systematic deficiencies. Especially for nowcasting (0–6 h applications the ensemble spread is smaller than the actual forecast error. This paper tries to generate probabilistic short range 2-m temperature forecasts by combining a state-of-the-art nowcasting method and a limited area ensemble system, and compares the results with statistical methods. The Integrated Nowcasting Through Comprehensive Analysis (INCA system, which has been in operation at the Central Institute for Meteorology and Geodynamics (ZAMG since 2006 (Haiden et al., 2011, provides short range deterministic forecasts at high temporal (15 min–60 min and spatial (1 km resolution. An INCA Ensemble (INCA-EPS of 2-m temperature forecasts is constructed by applying a dynamical approach, a statistical approach, and a combined dynamic-statistical method. The dynamical method takes uncertainty information (i.e. ensemble variance from the operational limited area ensemble system ALADIN-LAEF (Aire Limitée Adaptation Dynamique Développement InterNational Limited Area Ensemble Forecasting which is running operationally at ZAMG (Wang et al., 2011. The purely statistical method assumes a well-calibrated spread-skill relation and applies ensemble spread according to the skill of the INCA forecast of the most recent past. The combined dynamic-statistical approach adapts the ensemble variance gained from ALADIN-LAEF with non-homogeneous Gaussian regression (NGR which yields a statistical mbox{correction} of the first and second moment (mean bias and dispersion for Gaussian distributed continuous

  16. Measurement of Emissivity of Porous Ceramic Materials

    OpenAIRE

    BÜYÜKALACA, Orhan

    1998-01-01

    In this study, measurements of spectral and total emissivities of seven different porous ceramic materials and one ceramic fibre material are reported. Measurements were made for wavelength range from 1.2 µm to 20 µm and temperature range from 200 °C to 700 °C. It was found that total emissivity increases with increase of pore size but decreases with increase of temperature. The results showed all the porous ceramic materials tested to be much better than ceramic fibre in terms of total em...

  17. Low-temperature setting phosphate ceramics for stabilization of DOE problem low level mixed-waste: I. Material and waste form development

    International Nuclear Information System (INIS)

    Singh, D.; Wagh, A.; Knox, L.; Mayberry, J.

    1994-03-01

    Chemically bonded phosphate ceramics are proposed as candidates for solidification and stabilization of some of the open-quotes problemclose quotes DOE low-level mixed wastes at low-temperatures. Development of these materials is crucial for stabilization of waste streams which have volatile species and any use of high-temperature technology leads to generation of off-gas secondary waste streams. Several phosphates of Mg, Al, and Zr have been investigated as candidate materials. Monoliths of these phosphates were synthesized using chemical routes at room or slightly elevated temperatures. Detailed physical and chemical characterizations have been conducted on some of these phosphates to establish their durability. Magnesium ammonium phosphate has shown to possess excellent mechanical and as well chemical properties. These phosphates were also used to stabilize a surrogate ash waste with a loading ranging from 25-35 wt.%. Characterization of the final waste forms show that waste immobilization is due to both chemical stabilization and physical encapsulation of the surrogate waste which is desirable for waste immobilization

  18. 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...... 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...... with other similar oxide modules reported in the literature. A maximum power density of 4.5 kW/m2 was obtained for an oxide module comprising of 8 p-n couples at a temperature difference of 496 K, an encouraging result in the context of the present high temperature oxide modules....

  19. Some problems on materials tests in high temperature hydrogen base gas mixture

    International Nuclear Information System (INIS)

    Shikama, Tatsuo; Tanabe, Tatsuhiko; Fujitsuka, Masakazu; Yoshida, Heitaro; Watanabe, Ryoji

    1980-01-01

    Some problems have been examined on materials tests (creep rupture tests and corrosion tests) in high temperature mixture gas of hydrogen (80%H 2 + 15%CO + 5%CO 2 ) simulating the reducing gas for direct steel making. H 2 , CO, CO 2 and CH 4 in the reducing gas interact with each other at elevated temperature and produce water vapor (H 2 O) and carbon (soot). Carbon deposited on the walls of retorts and the water condensed at pipings of the lower temperature gas outlet causes blocking of gas flow. The gas reactions have been found to be catalyzed by the retort walls, and appropriate selection of the materials for retorts has been found to mitigate the problems caused by water condensation and carbon deposition. Quartz has been recognized to be one of the most promising materials for minimizing the gas reactions. And ceramic coating, namely, BN (born nitride) on the heat resistant superalloy, MO-RE II, has reduced the amounts of water vapor and deposited carbon (sooting) produced by gas reactions and has kept dew points of outlet gas below room temperature. The well known emf (thermo-electromotive force) deterioration of Alumel-Chromel thermocouples in the reducing gases at elevated temperatures has been also found to be prevented by the ceramic (BN) coating. (author)

  20. High-temperature Raman spectroscopy of solid oxide fuel cell materials and processes.

    Science.gov (United States)

    Pomfret, Michael B; Owrutsky, Jeffrey C; Walker, Robert A

    2006-09-07

    Chemical and material processes occurring in high temperature environments are difficult to quantify due to a lack of experimental methods that can probe directly the species present. In this letter, Raman spectroscopy is shown to be capable of identifying in-situ and noninvasively changes in material properties as well as the formation and disappearance of molecular species on surfaces at temperatures of 715 degrees C. The material, yttria-stabilized zirconia or YSZ, and the molecular species, Ni/NiO and nanocrystalline graphite, factor prominently in the chemistry of solid oxide fuel cells (SOFCs). Experiments demonstrate the ability of Raman spectroscopy to follow reversible oxidation/reduction kinetics of Ni/NiO as well as the rate of carbon disappearance when graphite, formed in-situ, is exposed to a weakly oxidizing atmosphere. In addition, the Raman active phonon mode of YSZ shows a temperature dependent shift that correlates closely with the expansion of the lattice parameter, thus providing a convenient internal diagnostic for identifying thermal gradients in high temperature systems. These findings provide direct insight into processes likely to occur in operational SOFCs and motivate the use of in-situ Raman spectroscopy to follow chemical processes in these high-temperature, electrochemically active environments.

  1. Effect of temperature and water activity on heat transfer in parsley leaves in the  range of temperatures 10–30 °C

    Directory of Open Access Journals (Sweden)

    Jiří Štencl

    2007-01-01

    Full Text Available The equilibrium moisture contents of parsley leaves were measured by the gravimetric dynamic method with continuous recording of changes in sample weight. Consequently water activity values were determined. Henderson equation was found to be a good model both for moisture adsorption and desorption. Isosteric heat of sorption was defined and determined in the temperature range of 10–30 °C. Clausius-Clapeyron equation was used to calculate the isosteric heat of sorption since no dependence on temperature in the analysed range was observed. The isosteric heats of sorption (qnst were indicated graphic in the form qnst versus moisture content. Values for isosteric heat of sorption ranged from 54.41 to 46.85 kJ/mol.

  2. Infrared normal spectral emissivity of Ti-6Al-4V alloy in the 500-1150 K temperature range

    Energy Technology Data Exchange (ETDEWEB)

    Gonzalez-Fernandez, L. [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Industria de Turbo Propulsores, S.A., Planta de Zamudio, Edificio 300, 48170 Zamudio, Bizkaia (Spain); Risueno, E. [CIC Energigune, Parque Tecnologico, Albert Einstein 48, 01510 Minano, Alava, Spain. (Spain); Perez-Saez, R.B., E-mail: raul.perez@ehu.es [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Instituto de Sintesis y Estudio de Materiales, Universidad del Pais Vasco, Apdo. 644,48080 Bilbao, Spain. (Spain); Tello, M.J. [Departamento de Fisica de la Materia Condensada, Facultad de Ciencia y Tecnologia, Universidad del Pais Vasco, Barrio Sarriena s/n, 48940 Leioa, Bizkaia (Spain); Instituto de Sintesis y Estudio de Materiales, Universidad del Pais Vasco, Apdo. 644,48080 Bilbao, Spain. (Spain)

    2012-11-15

    Highlights: Black-Right-Pointing-Pointer First heating cycle acts as a annealing, relieving the surface stresses. Black-Right-Pointing-Pointer Stress relieving occurs mainly above 900 K. Black-Right-Pointing-Pointer Emissivity decreases between 0.35 and 0.10 in the 2.5-22 {mu}m spectral range. Black-Right-Pointing-Pointer Emissivity increases linearly with temperature, with the same slope for {lambda} > 10 {mu}m. Black-Right-Pointing-Pointer Good agreement between resistivity and emissivity by means of Hagen-Rubens relation. - Abstract: Thermal radiative emissivity is related to the optical and electrical properties of materials, and it is a key parameter required in a large number of industrial applications. In the case of Ti-6Al-4V, spectral emissivity experimental data are not available for the range of temperatures between 400 and 1200 K, where almost all industrial applications take place. The experimental results in this paper show that the normal spectral emissivity decreases with wavelength from a value of about 0.35 at 2.5 {mu}m to about 0.10 at 22 {mu}m. At the same time, the spectral emissivity shows a slight linear increase with temperature between 500 and 1150 K, with approximately the same slope for all wavelengths. Additionally, the influence of the samples thermal history on the emissivity is studied. A strong decrease in the emissivity values appears due to the effect of surface stress relaxation processes. This means that the radiative properties of this alloy strongly depend on the surface stress state. A thermal treatment to relieve the surface stress should be carried out to achieve a steady state of the radiative properties. In addition, a good qualitative agreement is found between the temperature dependence of the electrical resistivity obtained using conventional measurements and the one obtained from the emissivity experimental results by using the Hagen-Rubens equation.

  3. Temperature-dependent layer breathing modes in two-dimensional materials

    Science.gov (United States)

    Maity, Indrajit; Maiti, Prabal K.; Jain, Manish

    2018-04-01

    Relative out-of-plane displacements of the constituent layers of two-dimensional materials give rise to unique low-frequency breathing modes. By computing the height-height correlation functions from molecular dynamics simulations, we show that the layer breathing modes (LBMs) can be mapped consistently to vibrations of a simple linear chain model. Our calculated thickness dependence of LBM frequencies for few-layer (FL) graphene and molybdenum disulfide (MoS2) are in excellent agreement with available experiments. Our results show a redshift of LBM frequency with an increase in temperature, which is a direct consequence of anharmonicities present in the interlayer interaction. We also predict the thickness and temperature dependence of LBM frequencies for FL hexagonal boron nitride. Our Rapid Communication provides a simple and efficient way to probe the interlayer interaction for layered materials and their heterostructures with the inclusion of anharmonic effects.

  4. Calculation of Distribution Dynamics of Inhomogeneous Temperature Field in Range of Fuel Elements by Using FreeFem++

    Science.gov (United States)

    Amosova, E. V.; Shishkin, A. V.

    2017-11-01

    This article introduces the result of studying the heat exchange in the fuel element of the nuclear reactor fuel magazine. Fuel assemblies are completed as a bundle of cylindrical fuel elements located at the tops of a regular triangle. Uneven distribution of fuel rods in a nuclear reactor’s core forms the inhomogeneity of temperature fields. This article describes the developed method for heat exchange calculation with the account for impact of an inhomogeneous temperature field on the thermal-physical properties of materials and unsteady effects. The acquired calculation results are used for evaluating the tolerable temperature levels in protective case materials.

  5. Electric resistance of nickel and niobium in the temperature range of 300-1300 K

    International Nuclear Information System (INIS)

    Novikov, I.I.; Roshchupkin, V.V.; Mozgovoj, A.G.; Semashko, N.A.

    1982-01-01

    The results of experimental investigation of nickel and niobium electric resistance on the wire samples by the potentiometric method in the temperature range of 300-1300 K are presented. Experimental data processing by the least square method is carried out; approximating equations of temperature dependence of the nickel and niobium electric resistance are prepared

  6. Influence of temperature on the spectral characteristics of semiconductor lasers in the visible range

    Science.gov (United States)

    Adamov, A. A.; Baranov, M. S.; Khramov, V. N.

    2018-04-01

    The results of studies on the effect of temperature on the output spectral characteristics of continuous semiconductor lasers of the visible range are presented. The paper presents the results of studying the spectral-optical radiation parameters of semiconductor lasers, their coherence lengths, and the dependence of the position of the spectral peak of the wavelength on temperature. This is necessary for the selection of the most optimal laser in order to use it for medical ophthalmologic diagnosis. The experiment was carried out using semiconductor laser modules based on a laser diode. The spectra were recorded by using a two-channel automated spectral complex based on the MDR-23 monochromator. Spectral dependences on the temperature of semiconductor lasers are obtained, in the range from 300 to 370 K. The possibility of determining the internal damage to the stabilization of laser modules without opening the case is shown, but only with the use of their spectral characteristics. The obtained data allow taking into account temperature characteristics and further optimization of parameters of such lasers when used in medical practice, in particular, in ophthalmologic diagnostics.

  7. Piezoelectricity above the Curie temperature? Combining flexoelectricity and functional grading to enable high-temperature electromechanical coupling

    Energy Technology Data Exchange (ETDEWEB)

    Mbarki, R. [Department of Mechanical Engineering, University of Houston, Houston, Texas 77204 (United States); Baccam, N. [Department of Mathematics, Southwestern University, Georgetown, Texas 78626 (United States); Dayal, Kaushik [Department of Civil and Environmental Engineering, Carnegie Mellon University, Pittsburgh, Pennsylvania 15213 (United States); Sharma, P. [Department of Mechanical Engineering and Department of Physics, University of Houston, Houston, Texas 77204 (United States)

    2014-03-24

    Most technologically relevant ferroelectrics typically lose piezoelectricity above the Curie temperature. This limits their use to relatively low temperatures. In this Letter, exploiting a combination of flexoelectricity and simple functional grading, we propose a strategy for high-temperature electromechanical coupling in a standard thin film configuration. We use continuum modeling to quantitatively demonstrate the possibility of achieving apparent piezoelectric materials with large and temperature-stable electromechanical coupling across a wide temperature range that extends significantly above the Curie temperature. With Barium and Strontium Titanate, as example materials, a significant electromechanical coupling that is potentially temperature-stable up to 900 °C is possible.

  8. Temperature stabilisation in Fischer–Tropsch reactors using phase change material (PCM)

    International Nuclear Information System (INIS)

    Odunsi, Ademola O.; O'Donovan, Tadhg S.; Reay, David A.

    2016-01-01

    The Fischer–Tropsch (FT) reaction is highly exothermic. The exothermicity combined with a high sensitivity of product selectivity to temperature constitute the main challenges in the design of FT reactors. Temperature control is particularly critical to the process in order to ensure longevity of the catalyst, optimise the product distribution, and to ensure thermo-mechanical reliability of the entire process. The use of encapsulated, Phase Change Material (PCM), in conjunction with a supervisory temperature control mechanism, could help mitigate these challenges and intensify the heat transport from the reactor. A 2D-axisymmetric, pseudo-homogeneous, steady-state model, with the dissipation of the enthalpy of reaction into an isothermal PCM sink, in a wall-cooled, single-tube fixed bed reactor is presented. Effective temperature control shows a shift in thermodynamic equilibrium, favouring the selectivity of longer chain hydrocarbons (C_5_+) to the disadvantage of CH_4 selectivity-a much desired outcome in the hydrocarbon Gas-to-Liquid (GTL) industry. - Highlights: • Phase change material is used to control temperature in a Fischer–Tropsch reactor. • Effective temperature control favours the production of C_5_+ over CH_4. • A 2D-axisymmetric, steady-state model is presented. • The model is verified against similar experimental work done in literature.

  9. 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.

  10. Interaction processes between vacancies and dislocations in molybdenum in the temperature range around 0.3 of the melting temperature

    International Nuclear Information System (INIS)

    Zelada-Lambri, G.I.; Lambri, O.A.; Bozzano, P.B.; Garcia, J.A.; Celauro, C.A.

    2008-01-01

    Mechanical spectroscopy, electrical resistivity and transmission electron microscopy studies have been performed on pre-strained neutron irradiated single crystalline molybdenum in order to check the interaction processes between vacancies and dislocations in the temperature range between room temperature and 1273 K. The anelastic relaxation in molybdenum which appears between 800 K and 1273 K has been separated in two different physical mechanisms depending on the temperature of appearance of the relaxation peak. The physical mechanism which controls the damping peak appearing at around 800 K was related with the dragging of jogs by the dislocation under movement assisted by vacancy diffusion. The damping peak which appears at higher temperatures of about 1000 K was more consistent with the formation and diffusion of vacancies assisted by the dislocation movement

  11. Interaction processes between vacancies and dislocations in molybdenum in the temperature range around 0.3 of the melting temperature

    Energy Technology Data Exchange (ETDEWEB)

    Zelada-Lambri, G.I. [Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Laboratorio de Materiales, Escuela de Ingenieria Electrica, Avenida Pellegrini 250, 2000 Rosario (Argentina); Lambri, O.A. [Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Laboratorio de Materiales, Escuela de Ingenieria Electrica, Avenida Pellegrini 250, 2000 Rosario (Argentina); Instituto de Fisica Rosario, Member of the CONICET' s Research Staff (Argentina)], E-mail: olambri@fceia.unr.edu.ar; Bozzano, P.B. [Laboratorio de Microscopia Electronica, Unidad de Actividad Materiales, Centro Atomico Constituyentes, Comision Nacional de Energia Atomica, Avenida General Paz 1499, 1650 San Martin (Argentina); Garcia, J.A. [Departamento de Fisica Aplicada II, Facultad de Ciencias y Tecnologia, Universidad del Pais Vasco, Apartado 644, 48080 Bilbao, Pais Vasco (Spain); Celauro, C.A. [Reactor Nuclear RA-4, Facultad de Ciencias Exactas, Ingenieria y Agrimensura, Universidad Nacional de Rosario, Riobamba y Berruti, 2000 Rosario (Argentina)

    2008-10-15

    Mechanical spectroscopy, electrical resistivity and transmission electron microscopy studies have been performed on pre-strained neutron irradiated single crystalline molybdenum in order to check the interaction processes between vacancies and dislocations in the temperature range between room temperature and 1273 K. The anelastic relaxation in molybdenum which appears between 800 K and 1273 K has been separated in two different physical mechanisms depending on the temperature of appearance of the relaxation peak. The physical mechanism which controls the damping peak appearing at around 800 K was related with the dragging of jogs by the dislocation under movement assisted by vacancy diffusion. The damping peak which appears at higher temperatures of about 1000 K was more consistent with the formation and diffusion of vacancies assisted by the dislocation movement.

  12. High Temperature Materials Laboratory Thirteenth Annual Report: October 1999 Through September 2000; ANNUAL

    International Nuclear Information System (INIS)

    Pasto, AE

    2001-01-01

    The High Temperature Materials Laboratory (HTML) is designed to assist American industries, universities, and governmental agencies develop advanced materials by providing a skilled staff and numerous sophisticated, often one-of-a-kind pieces of materials characterization equipment. It is a nationally designated user facility sponsored by the U.S. Department of Energy's (DOE's) office of Transportation Technologies, Energy Efficiency and Renewable Energy. Physically, it is a 64,500-ft(sup 2) building at the Oak Ridge National Laboratory (ORNL). The HTML houses six ''user centers,'' which are clusters of specialized equipment designed for specific types of properties measurements. The HTML was conceived and built in the mid-1980s in response to the oil embargoes of the 1970s. The concept was to build a facility that would allow direct work with American industry, academia, and government laboratories in providing advanced high-temperature materials such as structural ceramics for energy-efficient engines. The HTML's scope of work has since expanded to include other, non-high-temperature materials of interest to transportation and other industries

  13. 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.

  14. Formation of Medium Carbon TRIP Steel Microstructure During Annealing in the Intercritical Temperature Range

    Directory of Open Access Journals (Sweden)

    Kokosza A.

    2014-10-01

    Full Text Available The paper presents the results of research conducted on austenite formation in the microstructure of 41MnSi6-5 TRIP steel during annealing in the intercritical temperature range. The influence of the annealing temperature on the volume fraction of retained austenite in the microstructure of the investigated steel after water quenching was also determined.

  15. Communication: Anomalous temperature dependence of the intermediate range order in phosphonium ionic liquids

    International Nuclear Information System (INIS)

    Hettige, Jeevapani J.; Kashyap, Hemant K.; Margulis, Claudio J.

    2014-01-01

    In a recent article by the Castner and Margulis groups [Faraday Discuss. 154, 133 (2012)], we described in detail the structure of the tetradecyltrihexylphosphonium bis(trifluoromethylsulfonyl)-amide ionic liquid as a function of temperature using X-ray scattering, and theoretical partitions of the computationally derived structure function. Interestingly, and as opposed to the case in most other ionic-liquids, the first sharp diffraction peak or prepeak appears to increase in intensity as temperature is increased. This phenomenon is counter intuitive as one would expect that intermediate range order fades as temperature increases. This Communication shows that a loss of hydrophobic tail organization at higher temperatures is counterbalanced by better organization of polar components giving rise to the increase in intensity of the prepeak

  16. Temperature measurement of the reactor materials samples irradiated in the fuel channels of the RA reactor - Annex 16

    International Nuclear Information System (INIS)

    Nikolic, M.; Djalovic, M.

    1964-01-01

    Reactor materials as graphite, stainless steel, magnox, zirconium alloys, etc. were exposed to fast neutron flux inside the fuel elements specially adapted for this purpose. Samples in the form ampoules were placed in capsules inside the fuel channels and cooled by heavy water which cools the fuel elements. In order to monitor the samples temperature 42 thermocouples were placed in the samples. That was necessary for reactor safety reasons and for further interpretation of measured results. Temperature monitoring was done continuously by multichannel milivoltmeters. This paper describes the technique of introducing the thermocouples, compensation instruments, control of the cold ends and adaptation of the instruments for precision (0.5%) temperature measurement in the range 30 deg - 130 deg C; 30 deg - 280 deg C and 30 deg - 80 deg C [sr

  17. Temperature-sensitive host range mutants of herpes simplex virus type 2

    International Nuclear Information System (INIS)

    Koment, R.W.; Rapp, F.

    1975-01-01

    Herpesviruses are capable of several types of infection of a host cell. To investigate the early events which ultimately determine the nature of the virus-host cell interaction, a system was established utilizing temperature-sensitive mutants of herpes simplex virus type 2. Four mutants have been isolated which fail to induce cytopathic effects and do not replicate at 39 C in hamster embryo fibroblast cells. At least one mutant is virus DNA negative. Since intracellular complementation is detectable between pairs of mutants, a virus function is known to be temperature sensitive. However, all four mutants induce cytopathic effects and replicate to parental virus levels in rabbit kidney cells at 39 C. This suggests that a host cell function, lacking or nonfunctional in HEF cells but present in rabbit kidney cells at 39 C, is required for the replication of these mutants in hamster embryo fibroblast cells at 39 C. Therefore, we conclude that these mutants are both temperature sensitive and exhibit host range properties

  18. Positron range in tissue-equivalent materials: experimental microPET studies

    Science.gov (United States)

    Alva-Sánchez, H.; Quintana-Bautista, C.; Martínez-Dávalos, A.; Ávila-Rodríguez, M. A.; Rodríguez-Villafuerte, M.

    2016-09-01

    In this work an experimental investigation was carried out to study the effect that positron range has over positron emission tomography (PET) scans through measurements of the line spread function (LSF) in tissue-equivalent materials. Line-sources consisted of thin capillary tubes filled with 18F, 13N or 68Ga water-solution inserted along the axis of symmetry of cylindrical phantoms constructed with the tissue-equivalent materials: lung (inhale and exhale), adipose tissue, solid water, trabecular and cortical bone. PET scans were performed with a commercial small-animal PET scanner and image reconstruction was carried out with filtered-backprojection. Line-source distributions were analyzed using radial profiles taken on axial slices from which the spatial resolution was determined through the full-width at half-maximum, tenth-maximum, twentieth-maximum and fiftieth-maximum. A double-Gaussian model of the LSFs was used to fit experimental data which can be incorporated into iterative reconstruction methods. In addition, the maximum activity concentration in the line-sources was determined from reconstructed images and compared to the known values for each case. The experimental data indicates that positron range in different materials has a strong effect on both spatial resolution and activity concentration quantification in PET scans. Consequently, extra care should be taken when computing standard-uptake values in PET scans, in particular when the radiopharmaceutical is taken up by different tissues in the body, and more even so with high-energy positron emitters.

  19. Foundations of low-temperature plasma enhanced materials synthesis and etching

    Science.gov (United States)

    Oehrlein, Gottlieb S.; Hamaguchi, Satoshi

    2018-02-01

    Low temperature plasma (LTP)-based synthesis of advanced materials has played a transformational role in multiple industries, including the semiconductor industry, liquid crystal displays, coatings and renewable energy. Similarly, the plasma-based transfer of lithographically defined resist patterns into other materials, e.g. silicon, SiO2, Si3N4 and other electronic materials, has led to the production of nanometer scale devices that are the basis of the information technology, microsystems, and many other technologies based on patterned films or substrates. In this article we review the scientific foundations of both LTP-based materials synthesis at low substrate temperature and LTP-based isotropic and directional etching used to transfer lithographically produced resist patterns into underlying materials. We cover the fundamental principles that are the basis of successful application of the LTP techniques to technological uses and provide an understanding of technological factors that may control or limit material synthesis or surface processing with the use of LTP. We precede these sections with a general discussion of plasma surface interactions, the LTP-generated particle fluxes including electrons, ions, radicals, excited neutrals and photons that simultaneously contact and modify surfaces. The surfaces can be in the line of sight of the discharge or hidden from direct interaction for structured substrates. All parts of the article are extensively referenced, which is intended to help the reader study the topics discussed here in more detail.

  20. Melting temperature and enthalpy variations of phase change materials (PCMs): a differential scanning calorimetry (DSC) analysis

    Science.gov (United States)

    Sun, Xiaoqin; Lee, Kyoung Ok; Medina, Mario A.; Chu, Youhong; Li, Chuanchang

    2018-06-01

    Differential scanning calorimetry (DSC) analysis is a standard thermal analysis technique used to determine the phase transition temperature, enthalpy, heat of fusion, specific heat and activation energy of phase change materials (PCMs). To determine the appropriate heating rate and sample mass, various DSC measurements were carried out using two kinds of PCMs, namely N-octadecane paraffin and calcium chloride hexahydrate. The variations in phase transition temperature, enthalpy, heat of fusion, specific heat and activation energy were observed within applicable heating rates and sample masses. It was found that the phase transition temperature range increased with increasing heating rate and sample mass; while the heat of fusion varied without any established pattern. The specific heat decreased with the increase of heating rate and sample mass. For accuracy purpose, it is recommended that for PCMs with high thermal conductivity (e.g. hydrated salt) the focus will be on heating rate rather than sample mass.

  1. Theoretical and experimental study of AC electrical conduction mechanism in the low temperature range of p-CuIn3Se5

    Science.gov (United States)

    Essaleh, L.; Amhil, S.; Wasim, S. M.; Marín, G.; Choukri, E.; Hajji, L.

    2018-05-01

    In the present work, an attempt has been made to study theoretically and experimentally the AC electrical conduction mechanism in disordered semiconducting materials. The key parameter considered in this analysis is the frequency exponent s(ω , T) =( ∂ln(σAC(ω , T))/∂ ln(ω)T , where σAC is the AC electrical conductivity that depends on angular frequency ω and temperature T. In the theoretical part of this work, the effect of the barrier hopping energy, the polaron radius and the characteristic relaxation time is considered. The theoretical models of Quantum Mechanical Tunneling (QMT), Non overlapping Small Polaron Tunneling (NSPT), Overlapping Large Polaron Tunneling (OLPT) and Correlated Barrier Hopping (CBH) are considered to fit experimental data of σAC in p-CuIn3Se5 (p-CIS135) in the low temperature range up to 96 K. Some important parameters, as the polaron radius, the localization length and the barrier hopping energies, are estimated and their temperature and frequency dependence discussed.

  2. 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.

  3. Implications of stress range for inelastic analysis

    International Nuclear Information System (INIS)

    Karabin, M.E.; Dhalla, A.K.

    1981-01-01

    The elastic stress range over a complete load cycle is routinely used to formulate simplified rules regarding the inelastic behavior of structures operating at elevated temperature. For example, a 300 series stainless steel structure operating at elevated temperature, in all probability, would satisfy the ASME Boiler and Pressure Vessel Code criteria if the linearized elastic stress range is less than three times the material yield strength. However, at higher elastic stress ranges it is difficult to judge, a priori, that a structural component would comply with inelastic Code criteria after a detailed inelastic analysis. The purpose of this paper is to illustrate that it is not the elastic stress range but the stress intensities at specific times during a thermal transient which provide a better insight into the inelastic response of the structure. The specific example of the CRBRP flued head design demonstrates that the temperature differential between various parts of the structure can be changed by modifying the insulation pattern and heat flow path in the structure, without significantly altering the elastic stress range over a complete load cycle. However, the modified design did reduce the stress intensity during steady state elevated temperature operation. This modified design satisfied the inelastic Code criteria whereas the initial design failed to comply with the strain accumulation criterion

  4. Synthesis and characterization of novel electrolyte materials for intermediate temperature solid oxide fuel cells

    International Nuclear Information System (INIS)

    Chaubey, Nityanand; Chattopadhyaya, M.C.; Wani, B.N.; Bharadwaj, S.R.

    2008-01-01

    The high operating temperature of SOFCs using zirconia based electrolyte have several restrictions on materials used as interconnect and sealing and also requires use of expensive ceramics. Lowering the operating temperature of SOFCs to 600-800 deg C will enable to use cheaper materials and reduce the cost of fabrication while keeping the high power density. Lanthanide gallates are considered to be very promising solid electrolytes for intermediate temperature (600-800 deg C) solid oxide fuel cells (IT-SOFCs) due to their high ionic conductivity at lower temperatures. Phase purity of this material is a concern for the researchers for a long time. These materials are prepared at very high temperature (∼1400 deg C), since it is known that at around 1100 deg C, solubilities of Sr and Mg in LaGaO 3 were close to zero. Hence in the present work perovskite oxides of Ln 1-x Sr x Ga 1-y Mg y O 3-δ (Ln= Sm, Gd and x = 0.10, y=0.20) have been prepared by different methods i.e. solid state reaction, gel combustion and co-precipitation methods

  5. 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.

  6. Materials for high temperature solid oxide fuel cells

    International Nuclear Information System (INIS)

    Singhal, S.C.

    1987-01-01

    High temperature solid oxide fuel cells show great promise for economical production of electricity. These cells are based upon the ability of stabilized zirconia to operate as an oxygen ion conductor at elevated temperatures. The design of the tubular solid oxide fuel cell being pursued at Westinghouse is illustrated. The cell uses a calcia-stabilized zironcia porous support tube, which acts both as a structural member onto which the other cell components are fabricated in the form of thin layers, and as a functional member to allow the passage, via its porosity, of air (or oxygen) to the air electrode. This paper summarizes the materials and fabrication processes for the various cell components

  7. Materials Sciences Division long range plan

    International Nuclear Information System (INIS)

    1984-12-01

    The intent of this document is to provide a framework for programmatic guidance into the future for Materials Sciences. The Materials Sciences program is the basic research program for materials in the Department of Energy. It includes a wide variety of activities associated with the sciences related to materials. It also includes the support for developing, constructing, and operating major facilities which are used extensively but not exclusively by the materials sciences

  8. 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.

  9. 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.

  10. Influence of deuterium content on tensile behavior of Zr-2.5Nb pressure tube material in the temperature range of ambient to 300 degC

    International Nuclear Information System (INIS)

    Bind, A.K.; Singh, R.N.; Chakravartty, J.K.; Dhandharia, Priyesh; Ghosh, Agnish; More, Nitin S.; Chhatre, A.G.; Vijayakumar, S.

    2011-08-01

    Tensile properties of autoclaved zirconium-2.5 wt. % niobium pressure tube material were evaluated by uniaxial tension tests at temperatures between 25 and 300 degC and under strain-rates of 1.075 x 10 -4 /s. Six number of Zr-2.5Nb alloy pressure tube spools of length 130 mm were obtained from pressure tube number 19-2557-2. Five spools were polished with abrasive paper to remove the oxide layer. These spools were gaseously charged with controlled amount of deuterium. The target deuterium concentrations were 25, 50, 75, 100 and 200 wppm of hydrogen equivalent. Ten samples were machined by EDM wire cutting from every spool. The tensile specimen axis was oriented along longitudinal direction of the tube. Metallographic examination of the deuterium charged samples suggested that the deuterides were predominantly circumferential deuterides. Analysis of tensile results showed that both yield and ultimate tensile strengths of this alloy decreased monotonically with increasing test temperatures. The tensile ductility decreased marginally with increase in test temperature from ambient to 300 degC. It was also observed that both strength and ductility appear to be unaffected by deuterium content at all temperatures, thereby suggesting that at least up to 200 wppm (Heq.) of deuterium tensile properties are not influenced by deuterium. (author)

  11. Plastic behaviour of Zircaloy-4 in the temperature range 77-1000 K

    International Nuclear Information System (INIS)

    Derep, J.L.; Ibrahim, S.; Rouby, D.; Fantozzi, G.; Gobin, P.

    1979-01-01

    Tensile tests were carried out on Zircaloy-4 over a temperature range 77-1000 K. So, we have determined the flow stress variations as a function of temperature and strain rate. Two thermally activated zones were observed between about 77 and 600 K, a plateau stress between 600 and 700 K and an other thermally activated zone above 700 K. The various mechanisms which can be responsible for the thermally activated and athermal zones are discussed in the light of experimental results. The mechanical behaviour of Zircaloy-4 appears similar to the zirconium-oxygen alloys one. (orig.) [de

  12. In-situ high temperature irradiation setup for temperature dependent structural studies of materials under swift heavy ion irradiation

    International Nuclear Information System (INIS)

    Kulriya, P.K.; Kumari, Renu; Kumar, Rajesh; Grover, V.; Shukla, R.; Tyagi, A.K.; Avasthi, D.K.

    2015-01-01

    An in-situ high temperature (1000 K) setup is designed and installed in the materials science beam line of superconducting linear accelerator at the Inter-University Accelerator Centre (IUAC) for temperature dependent ion irradiation studies on the materials exposed with swift heavy ion (SHI) irradiation. The Gd 2 Ti 2 O 7 pyrochlore is irradiated using 120 MeV Au ion at 1000 K using the high temperature irradiation facility and characterized by ex-situ X-ray diffraction (XRD). Another set of Gd 2 Ti 2 O 7 samples are irradiated with the same ion beam parameter at 300 K and simultaneously characterized using in-situ XRD available in same beam line. The XRD studies along with the Raman spectroscopic investigations reveal that the structural modification induced by the ion irradiation is strongly dependent on the temperature of the sample. The Gd 2 Ti 2 O 7 is readily amorphized at an ion fluence 6 × 10 12 ions/cm 2 on irradiation at 300 K, whereas it is transformed to a radiation-resistant anion-deficient fluorite structure on high temperature irradiation, that amorphized at ion fluence higher than 1 × 10 13 ions/cm 2 . The temperature dependent ion irradiation studies showed that the ion fluence required to cause amorphization at 1000 K irradiation is significantly higher than that required at room temperature irradiation. In addition to testing the efficiency of the in-situ high temperature irradiation facility, the present study establishes that the radiation stability of the pyrochlore is enhanced at higher temperatures

  13. Corrosion of Ceramic Materials

    Science.gov (United States)

    Opila, Elizabeth J.; Jacobson, Nathan S.

    1999-01-01

    Non-oxide ceramics are promising materials for a range of high temperature applications. Selected current and future applications are listed. In all such applications, the ceramics are exposed to high temperature gases. Therefore it is critical to understand the response of these materials to their environment. The variables to be considered here include both the type of ceramic and the environment to which it is exposed. Non-oxide ceramics include borides, nitrides, and carbides. Most high temperature corrosion environments contain oxygen and hence the emphasis of this chapter will be on oxidation processes.

  14. Investigation of the thermophysical properties of oxide ceramic materials at liquid-helium temperatures

    International Nuclear Information System (INIS)

    Taranov, A. V.; Khazanov, E. N.

    2008-01-01

    The main regularities in the transport of thermal phonons in oxide ceramic materials are investigated at liquid-helium temperatures. The dependences of the thermophysical characteristics of ceramic materials on their structural parameters (such as the grain size R, the grain boundary thickness d, and the structure of grain boundaries) are analyzed. It is demonstrated that, in dense coarse-grained ceramic materials with qR>>1 (where q is the phonon wave vector), the grain boundaries and the grain size are the main factors responsible for the thermophysical characteristics of the material at liquid-helium temperatures. A comparative analysis of the thermophysical characteristics of optically transparent ceramic materials based on the Y 3 Al 5 O 12 (YAG) and Y 2 O 3 cubic oxides synthesized under different technological conditions is performed using the proposed criterion

  15. 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...

  16. The mechanical properties of fluoride salts at elevated temperatures. [candidate thermal energy storage materials for solar dynamic systems

    Science.gov (United States)

    Raj, S. V.; Whittenberger, J. D.

    1989-01-01

    The deformation behavior of CaF2 and LiF single crystals compressed in the 111 and the 100 line directions, respectively, are compared with the mechanical properties of polycrystalline LiF-22 (mol pct) CaF2 eutectic mixture in the temperature range 300 to 1275 K for strain rates varying between 7 x 10 to the -7th and 0.2/s. The true stress-strain curves for the single crystals were found to exhibit three stages in an intermediate range of temperatures and strain rates, whereas those for the eutectic showed negative work-hardening rates after a maximum stress. The true stress-strain rate data for CaF2 and LiF-22 CaF2 could be represented by a power-law relation with the strain rate sensitivities lying between 0.05 and 0.2 for both materials. A similar relation was found to be unsatisfactory in the case of LiF.

  17. High temperature outgassing tests on materials used in the DIII-D tokamak

    International Nuclear Information System (INIS)

    Holtrop, K.L.; Hansink, M.J.

    2006-01-01

    This article is a continuation of previous work on determining the outgassing characteristics of materials used in the DIII-D magnetic fusion tokamak [K. L. Holtrop, J. Vac. Sci. Technol. A 17, 2064 (1999)]. Achievement of high performance plasma discharges in the DIII-D tokamak requires careful control of impurity levels. Among the techniques used to control impurities are routine bakes of the vacuum vessel to an average temperature of 350 deg. C. Materials used in DIII-D must release only very small amounts of impurities (below 2x10 -6 mole) at this temperature that could be transferred to the first wall materials and later contaminate plasma discharges. To better study the behavior of materials proposed for use in DIII-D at elevated temperatures, the initial outgassing test chamber was improved to include an independent heating control of the sample and a simple load lock chamber. The goal was to determine not only the total degassing rate of the material during baking, but to also determine the gas species composition and to obtain a quantitative estimate of the degassing rate of each species by the use of a residual gas analyzer. Initial results for aluminum anodized using three different processes, stainless steel plated with black oxide and black chrome, and a commercially available fiber optic feedthrough will be presented

  18. Asymetric change of daily temperature range: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Kukla, G. [ed.] [Columbia Univ., Palisades, NY (United States). Lamont-Doherty Earth Observatory; Karl, T.R. [ed.] [National Climatic Data Center, Asheville, NC (United States); Riches, M.R. [ed.] [USDOE, Washington, DC (United States)

    1994-04-01

    This report is a compilation of abstracts of papers presented at the MINIMAX workshop. Topics include; temperature fluxes, influence of clouds on temperature, anthropogenic influences on temperature flux, and carbon dioxide and aerosol induced greenhouse effect.

  19. Asymetric change of daily temperature range: Proceedings

    International Nuclear Information System (INIS)

    Kukla, G.; Riches, M.R.

    1994-04-01

    This report is a compilation of abstracts of papers presented at the MINIMAX workshop. Topics include; temperature fluxes, influence of clouds on temperature, anthropogenic influences on temperature flux, and carbon dioxide and aerosol induced greenhouse effect

  20. EXAFS, Determination of Short Range Order and Local Structures in Materials

    NARCIS (Netherlands)

    Koningsberger, D.C.; Prins, R.

    1981-01-01

    Extended X-ray Absorption Fine Structure (EXAFS) is a powerful method of determining short range order and local structures in materials using X-ray photons produced by a synchrotron light source, or in-house by a high intensity rotating anode X-ray generator. The technique has provided valuable

  1. Brightness temperature of the ''quiet'' Sun in the millimeter wavelength range

    International Nuclear Information System (INIS)

    Pelyushenko, S.A.

    1982-01-01

    Results are presented of recalibration of the data available for measurements of the solar brightness temperature Tsub(s) made by comparison with the lunar radio emission. A spectrum has been obtained of the ''quiet'' Sun radio emission in the range of 1-20 mm. The mean square spread of data does not exceed +-(from 3 to 4)%. The ''quiet'' Sun spectrum has a form of: Tsub(c)=(6150+-70)lambdasup(01+-0.01)[mm]K in the wavelength interval of lambda=(1-6) mm and Tsub(c)=(3470+-80)lambdasup(0.42+-0.01) [mm]K in the wavelength interval of lambda=(7-20) mm on approximation of recalibrated values of Tsub(c) with a linear dependence using the mean-square-root method. The obtained spectral characteristics of the ''quiet'' Sun radio frequency emission in the mullimeter wavelength range testify on the spectrum flatteming in the (1-6) mm wavelength range

  2. Thermal expansion and phase transformation studies on some materials by high temperature x-ray powder diffractometry

    International Nuclear Information System (INIS)

    Rajagopalan, S.; Kutty, K.V.G.; Jajoo, H.K.; Ananthakrishnan, S.K.; Asurvatharaman, R.

    1988-01-01

    A high temperature chamber based on electrical resistance heating has been integrated to an existing x-ray powder diffractometer. The system is capable of going upto 2500degC at programmed rates of heating. Temperature measurement is carried out by means by Pt/Rh or W/Re thermocouples or by optical pyrometry depending upon the temperature range. Provision exists for performing high temperature x-ray diffractometry in vacuum or in a gaseous atmosphere of low x-ray absorption. The x-ray optical alignment has been ensured by accurately measuring the unit cell lengths of x-ray diffraction standards like silicon and tungsten. The thermocouples have been calibrated within the system by monitoring the melting points of gold and silver. The well characterized transformation of zirconia from the monoclinic to tetragonal structure occuring around 1100degC has been satisfactorily reproduced . The high temperature phase transitions in some rare earth oxides have been studi ed. lattice parameter measurements on a variety of materials as a function of temperature upto 1500degC have been carried out and the data found to be in agreement with the literature values. From the measured lattice parameter values, percentage thermal expansion and coefficients of thermal expansion have been calculated for many substances from room temperature to 15000degC. (author). 20 refs., 9 figs

  3. Scanning and Transmission Electron Microscopy of High Temperature Materials

    Science.gov (United States)

    1994-01-01

    Software and hardware updates to further extend the capability of the electron microscope were carried out. A range of materials such as intermetallics, metal-matrix composites, ceramic-matrix composites, ceramics and intermetallic compounds, based on refractory elements were examined under this research. Crystal structure, size, shape and volume fraction distribution of various phases which constitute the microstructures were examined. Deformed materials were studied to understand the effect of interfacial microstructure on the deformation and fracture behavior of these materials. Specimens tested for a range of mechanical property requirements, such as stress rupture, creep, low cycle fatigue, high cycle fatigue, thermomechanical fatigue, etc. were examined. Microstructural and microchemical stability of these materials exposed to simulated operating environments were investigated. The EOIM Shuttle post-flight samples were also examined to understand the influence of low gravity processing on microstructure. In addition, fractographic analyses of Nb-Zr-W, titanium aluminide, molybdenum silicide and silicon carbide samples were carried out. Extensive characterization of sapphire fibers in the fiber-reinforced composites made by powder cloth processing was made. Finally, pressure infiltration casting of metal-matrix composites was carried out.

  4. 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.

  5. 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

  6. Generalized empirical equation for the extrapolated range of electrons in elemental and compound materials

    International Nuclear Information System (INIS)

    Lima, W. de; Poli CR, D. de

    1999-01-01

    The extrapolated range R ex of electrons is useful for various purposes in research and in the application of electrons, for example, in polymer modification, electron energy determination and estimation of effects associated with deep penetration of electrons. A number of works have used empirical equations to express the extrapolated range for some elements. In this work a generalized empirical equation, very simple and accurate, in the energy region 0.3 keV - 50 MeV is proposed. The extrapolated range for elements, in organic or inorganic molecules and compound materials, can be well expressed as a function of the atomic number Z or two empirical parameters Zm for molecules and Zc for compound materials instead of Z. (author)

  7. Report of tests carried out on Viton O-ring seals to assess suitability for operation over the temperature range -400 C to +2200 C when used in Package Design 2863B

    International Nuclear Information System (INIS)

    1996-01-01

    To satisfy the requirements of US Regulatory bodies the O-ring seals in the containment vessels of Package Design 2863B have to be shown to operate satisfactorily (i.e. remain leaktight) at the extremes of temperature that they are expected to experience during both normal and hypothetical accident conditions of transport. For Package Design 2863B this effectively means that the seals must remain leaktight over the temperature range -40 C to + 220 C, but to ensure that an adequate safety margin exists the seals should preferably remain leaktight over the range -50 C to +250 C. This test report describes the procedures and results of tests carried out on Viton seals over the temperature range -50 C to +250 C. The variability of the results at low temperature, by both pressure drop and helium leakage testing, would indicate that the particular formulation of Viton tested cannot be used to provide a reliable leaktight seal at -40 C. Although the results of the pressure drop tests at high temperature were satisfactory, insufficient testing has been carried out using helium leakage testing to draw a firm conclusion about the high temperature performance of the material tested

  8. Complex technique for materials hardness measurement

    Energy Technology Data Exchange (ETDEWEB)

    Krashchenko, V P; Oksametnaya, O B

    1984-01-01

    A review of existing methods of measurement of material hardness in national and foreign practice has been made. A necessity of improving the technique of material hardness measurement in a wide temperature range and insuring load change with indenting, continuity of imprint application, smooth changing of temperatures along a sample length, and deformation rate control has been noted.

  9. Zero thermal expansion and ferromagnetism in cubic Sc(1-x)M(x)F3 (M = Ga, Fe) over a wide temperature range.

    Science.gov (United States)

    Hu, Lei; Chen, Jun; Fan, Longlong; Ren, Yang; Rong, Yangchun; Pan, Zhao; Deng, Jinxia; Yu, Ranbo; Xing, Xianran

    2014-10-01

    The rare physical property of zero thermal expansion (ZTE) is intriguing because neither expansion nor contraction occurs with temperature fluctuations. Most ZTE, however, occurs below room temperature. It is a great challenge to achieve isotropic ZTE at high temperatures. Here we report the unconventional isotropic ZTE in the cubic (Sc1-xMx)F3 (M = Ga, Fe) over a wide temperature range (linear coefficient of thermal expansion (CTE), αl = 2.34 × 10(-7) K(-1), 300-900 K). Such a broad temperature range with a considerably negligible CTE has rarely been documented. The present ZTE property has been designed using the introduction of local distortions in the macroscopic cubic lattice by heterogeneous cation substitution for the Sc site. Even though the macroscopic crystallographic structure of (Sc0.85Ga0.05Fe0.1)F3 adheres to the cubic system (Pm3̅m) according to the results of X-ray diffraction, the local structure exhibits a slight rhombohedral distortion. This is confirmed by pair distribution function analysis of synchrotron radiation X-ray total scattering. This local distortion may weaken the contribution from the transverse thermal vibration of fluorine atoms to negative thermal expansion, and thus may presumably be responsible for the ZTE. In addition, the present ZTE compounds of (Sc1-xMx)F3 can be functionalized to exhibit high-Tc ferromagnetism and a narrow-gap semiconductor feature. The present study shows the possibility of obtaining ZTE materials with multifunctionality in future work.

  10. Infrared normal spectral emissivity of Ti–6Al–4V alloy in the 500–1150 K temperature range

    International Nuclear Information System (INIS)

    González-Fernández, L.; Risueño, E.; Pérez-Sáez, R.B.; Tello, M.J.

    2012-01-01

    Highlights: ► First heating cycle acts as a annealing, relieving the surface stresses. ► Stress relieving occurs mainly above 900 K. ► Emissivity decreases between 0.35 and 0.10 in the 2.5–22 μm spectral range. ► Emissivity increases linearly with temperature, with the same slope for λ > 10 μm. ► Good agreement between resistivity and emissivity by means of Hagen–Rubens relation. - Abstract: Thermal radiative emissivity is related to the optical and electrical properties of materials, and it is a key parameter required in a large number of industrial applications. In the case of Ti–6Al–4V, spectral emissivity experimental data are not available for the range of temperatures between 400 and 1200 K, where almost all industrial applications take place. The experimental results in this paper show that the normal spectral emissivity decreases with wavelength from a value of about 0.35 at 2.5 μm to about 0.10 at 22 μm. At the same time, the spectral emissivity shows a slight linear increase with temperature between 500 and 1150 K, with approximately the same slope for all wavelengths. Additionally, the influence of the samples thermal history on the emissivity is studied. A strong decrease in the emissivity values appears due to the effect of surface stress relaxation processes. This means that the radiative properties of this alloy strongly depend on the surface stress state. A thermal treatment to relieve the surface stress should be carried out to achieve a steady state of the radiative properties. In addition, a good qualitative agreement is found between the temperature dependence of the electrical resistivity obtained using conventional measurements and the one obtained from the emissivity experimental results by using the Hagen–Rubens equation.

  11. Composite Materials under Extreme Radiation and Temperature Environments of the Next Generation Nuclear Reactors

    International Nuclear Information System (INIS)

    Simos, N.

    2011-01-01

    In the nuclear energy renaissance, driven by fission reactor concepts utilizing very high temperatures and fast neutron spectra, materials with enhanced performance that exceeds are expected to play a central role. With the operating temperatures of the Generation III reactors bringing the classical reactor materials close to their performance limits there is an urgent need to develop and qualify new alloys and composites. Efforts have been focused on the intricate relations and the high demands placed on materials at the anticipated extreme states within the next generation fusion and fission reactors which combine high radiation fluxes, elevated temperatures and aggressive environments. While nuclear reactors have been in operation for several decades, the structural materials associated with the next generation options need to endure much higher temperatures (1200 C), higher neutron doses (tens of displacements per atom, dpa), and extremely corrosive environments, which are beyond the experience on materials accumulated to-date. The most important consideration is the performance and reliability of structural materials for both in-core and out-of-core functions. While there exists a great body of nuclear materials research and operating experience/performance from fission reactors where epithermal and thermal neutrons interact with materials and alter their physio-mechanical properties, a process that is well understood by now, there are no operating or even experimental facilities that will facilitate the extreme conditions of flux and temperature anticipated and thus provide insights into the behaviour of these well understood materials. Materials, however, still need to be developed and their interaction and damage potential or lifetime to be quantified for the next generation nuclear energy. Based on material development advances, composites, and in particular ceramic composites, seem to inherently possess properties suitable for key functions within the

  12. Application of headspace for research volatile organic compounds emitted from building materials

    Directory of Open Access Journals (Sweden)

    Kultys Beata

    2018-01-01

    Full Text Available Headspace technique and gas chromatography method with mas detector has been used for the determination of volatile organic compounds (VOC emitted from various building and finishing materials, such as sealing foams, mounting strips, paints, varnishes, floor coverings. The tests were carried out for different temperatures (in the temperature range of 60 to 180 °C and the time of heated vials with tested materials inside. These tests were conducted to verify the possibility of use this method of determination the VOC emission. Interpretation of chromatograms and mass spectra allowed to identify the type of compounds emitted from the tested materials and the optimum time and temperature for each type of material was determined. The increase in heating temperature of the samples resulted in increase the type and number of identified compounds: for four materials the increase was in the whole temperature range, for others it was from 90 °C. On the other hand, emission from mineral wool was low in whole temperature range. 30-minutes heating of the samples was sufficient to identify emitted compounds for most of tested materials. Applying a longer time, i.e. 24 hours, significantly increased the sensitivity of the method.

  13. Wide-range nuclear reactor temperature control using automatically tuned fuzzy logic controller

    International Nuclear Information System (INIS)

    Ramaswamy, P.; Edwards, R.M.; Lee, K.Y.

    1992-01-01

    In this paper, a fuzzy logic controller design for optimal reactor temperature control is presented. Since fuzzy logic controllers rely on an expert's knowledge of the process, they are hard to optimize. An optimal controller is used in this paper as a reference model, and a Kalman filter is used to automatically determine the rules for the fuzzy logic controller. To demonstrate the robustness of this design, a nonlinear six-delayed-neutron-group plant is controlled using a fuzzy logic controller that utilizes estimated reactor temperatures from a one-delayed-neutron-group observer. The fuzzy logic controller displayed good stability and performance robustness characteristics for a wide range of operation

  14. Primary system temperature limits and transient mitigation

    Energy Technology Data Exchange (ETDEWEB)

    Drucker, G.S.; Bost, D.S.

    1978-10-03

    Results of a study to determine the limiting temperature conditions in a large reactor system are presented. The study considers a sodium-cooled breeder reactor system having a loop-type primary system configuration. A temperature range of 930 to 1050/sup 0/F in reactor outlet temperature is covered. Significant findings were that the use of the materials for the 930/sup 0/F reference design, i.e., a core material of 20% cold-worked 316 stainless steel, a primary piping material of 316SS, and a steam generator material of unstabilized 2-1/4 Cr - 1 Mo resulted in limiting conditions in component performance at the higher temperatures. Means to circumvent these limits through the use of alternate materials, mitigation of thermal transients, and/or design changes are presented. The economic incentive to make some materials changes is also presented.

  15. Thermal Annealing to Modulate the Shape Memory Behavior of a Biobased and Biocompatible Triblock Copolymer Scaffold in the Human Body Temperature Range.

    Science.gov (United States)

    Merlettini, Andrea; Gigli, Matteo; Ramella, Martina; Gualandi, Chiara; Soccio, Michelina; Boccafoschi, Francesca; Munari, Andrea; Lotti, Nadia; Focarete, Maria Letizia

    2017-08-14

    A biodegradable and biocompatible electrospun scaffold with shape memory behavior in the physiological temperature range is here presented. It was obtained starting from a specifically designed, biobased PLLA-based triblock copolymer, where the central block is poly(propylene azelate-co-propylene sebacate) (P(PAz60PSeb40)) random copolymer. Shape memory properties are determined by the contemporary presence of the low melting crystals of the P(PAz60PSeb40) block, acting as switching segment, and of the high melting crystal phase of PLLA blocks, acting as physical network. It is demonstrated that a straightforward annealing process applied to the crystal phase of the switching element gives the possibility to tune the shape recovery temperature from about 25 to 50 °C, without the need of varying the copolymer's chemical structure. The thermal annealing approach here presented can be thus considered a powerful strategy for "ad hoc" programming the same material for applications requiring different recovery temperatures. Fibroblast culture experiments demonstrated scaffold biocompatibility.

  16. Single-ion polymer electrolyte membranes enable lithium-ion batteries with a broad operating temperature range.

    Science.gov (United States)

    Cai, Weiwei; Zhang, Yunfeng; Li, Jing; Sun, Yubao; Cheng, Hansong

    2014-04-01

    Conductive processes involving lithium ions are analyzed in detail from a mechanistic perspective, and demonstrate that single ion polymeric electrolyte (SIPE) membranes can be used in lithium-ion batteries with a wide operating temperature range (25-80 °C) through systematic optimization of electrodes and electrode/electrolyte interfaces, in sharp contrast to other batteries equipped with SIPE membranes that display appreciable operability only at elevated temperatures (>60 °C). The performance is comparable to that of batteries using liquid electrolyte of inorganic salt, and the batteries exhibit excellent cycle life and rate performance. This significant widening of battery operation temperatures coupled with the inherent flexibility and robustness of the SIPE membranes makes it possible to develop thin and flexible Li-ion batteries for a broad range of applications. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  17. 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.

  18. Evaluation of high temperature capacitor dielectrics

    Science.gov (United States)

    Hammoud, Ahmad N.; Myers, Ira T.

    1992-01-01

    Experiments were carried out to evaluate four candidate materials for high temperature capacitor dielectric applications. The materials investigated were polybenzimidazole polymer and three aramid papers: Voltex 450, Nomex 410, and Nomex M 418, an aramid paper containing 50 percent mica. The samples were heat treated for six hours at 60 C and the direct current and 60 Hz alternating current breakdown voltages of both dry and impregnated samples were obtained in a temperature range of 20 to 250 C. The samples were also characterized in terms of their dielectric constant, dielectric loss, and conductivity over this temperature range with an electrical stress of 60 Hz, 50 V/mil present. Additional measurements are underway to determine the volume resistivity, thermal shrinkage, and weight loss of the materials. Preliminary data indicate that the heat treatment of the films slightly improves the dielectric properties with no influence on their breakdown behavior. Impregnation of the samples leads to significant increases in both alternating and direct current breakdown strength. The results are discussed and conclusions made concerning their suitability as high temperature capacitor dielectrics.

  19. Experimental and numerical analysis of the static and dynamic crack growth resistance behaviour of structural steels in the temperature range from 20 C to 350 C

    International Nuclear Information System (INIS)

    Aurich, D.; Gerwien, P.; Huenecke, J.; Klingbeil, D.; Krafka, H.; Kuenecke, G.; Ohm, K.; Veith, H.; Wossidlo, P.; Haecker, R.

    1998-01-01

    The crack growth resistance behaviour of the steels StE 460 and 22NiMoCr3-7 was determined in the temperature range from 23 C to 350 C by means of C(T), M(T), and ISO-V specimens tested under quasistatic and dynamic loads. The Russian steel 15Ch2NMFA-A was tested at room temperature and 50 C. In the steels StE 460 and 22 NiMoCr3-7, the minimum crack growth resistance is observed at about 250 C, with measured values always being higher for the latter steel type. The crack growth resistance behaviour of the tested materials correlates with the behaviour of flow curve, yield strength, and notch impact toughness as a function of temperature. Impact tests of ISO-V specimens give higher crack resistance values than quasistatic load tests, and the temperature dependence is significantly lower than those of specimens tested under static loads. A metallurgical analysis of the materials shows the causes of the dissimilar behaviour. The stretching zones determined for the C(T) specimen correspond to the toughness of the steels examined, and they are not much influenced by the temperature. The numerical analysis using damaging models for simulation of ductile crack growth is reported for all specimen types and two different temperatures each. (orig./CB) [de

  20. Wide Temperature Range DC-DC Boost Converters for Command/Control/Drive Electronics, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — We shall develop wide temperature range DC-DC boost converters that can be fabricated using commercial CMOS foundries. The boost converters will increase the low...

  1. Calculated and experimental definition of neutron-physical and temperature conditions of material testing in the SM reactor

    International Nuclear Information System (INIS)

    Toporova, V.G.; Pimenov, V.V.

    2004-01-01

    Full text: Reactor material science is one of the main scientific directions of the RIAR activities. Particularly, a wide range of materials and products testing under irradiation is performed in reactor facility SM (RF SM). To solve the tasks specified in the technical specification for an experiment, previously, the test conditions are chosen. At the minimum a space-energy distribution of neutrons and heating rate in the materials under test are important as well as temperature conditions of irradiation. The up-to-date software and libraries of nuclear data allow modeling of neutron-material interaction processes to a considerable degree of details and also obtaining a true neutron distribution by calculation methods. As a result of a great scope of work on verification, a calculation model, developed on the basis of a package of applied software MCU (option MCU-4/SM22) and analogue Monte-Carlo method, is widely used at RIAR. The MCU geometric module makes it possible to model the SM core and reflector in three-dimensional geometry with sufficient accuracy and to describe all elements of the channel structure and irradiation device with specimens. The calculation model of RF SM is tested using the results of activation experiments performed in its critical assembly, geometric parameters and structural materials of which correspond completely with the prototype. The difference in the calculated and experimental values is less than 2.5%. Possibilities of the calculated estimation of operating temperature conditions of absorbing elements under irradiation should be considered separately. As the conducted calculations and their analysis show, to define the fuel column temperature correctly, one needs reliable data on thermal-physical parameters of materials, especially ceramic ones, such as titanium, dysprosium or boron carbide. This is very important for boron carbide-absorbing elements for actually all their operation parameters (such as: gas release, swelling

  2. High temperature viscoplastic ratchetting: Material response or modeling artifact

    International Nuclear Information System (INIS)

    Freed, A.D.

    1991-01-01

    Ratchetting, the net accumulation of strain over a loading cycle, is a deformation mechanism that leads to distortions in shape, often resulting in a loss of function that culminates in structural failure. Viscoplastic ratchetting is prevalent at high homologous temperatures where viscous characteristics are prominent in material response. This deformation mechanism is accentuated by the presence of a mean stress; a consequence of interaction between thermal gradients and structural constraints. Favorable conditions for viscoplastic ratchetting exist in the Stirling engines being developed by the National Aeronautics and Space Administration (NASA) and the Department of Energy (DOE) for space and terrestrial power applications. To assess the potential for ratchetting and its effect on durability of high temperature structures requires a viscoplastic analysis of the design. But ratchetting is a very difficult phenomenon to accurately model. One must therefore ask whether the results from such an analysis are indicative of actual material behavior, or if they are artifacts of the theory being used in the analysis. There are several subtle aspects in a viscoplastic model that must be dealt with in order to accurately model ratchetting behavior, and therefore obtain meaningful predictions from it. In this paper, some of these subtlties and the necessary ratchet experiments needed to obtain an accurate viscoplastic representation of a material are discussed

  3. Analysis of the device characteristics of AlGaN/GaN HEMTs over a wide temperature range

    International Nuclear Information System (INIS)

    Zhao, M.; Liu, X.Y.; Zheng, Y.K.; Li, Yankui; Ouyang, Sihua

    2013-01-01

    Highlights: ► We report the behavior of the current–voltage characteristics of AlGaN/GaN HEMT in the temperature range of 223–398 K. ► The origin of the leakage current and the current transport behaviors are reported. ► There is a linear relationship between the barrier height and the ideality factor, which is attributed to barrier height in homogeneities. -- Abstract: In this study, we investigate the behavior of the current–voltage (I–V) characteristics of AlGaN/GaN HEMT in the temperature range of 223–398 K. Temperature dependent device characteristics and the current transport mechanism are reported. It is observed that the Schottky barrier height Φ increases and the ideality factor n decreases with temperature. There is a linear relationship between the barrier height and the ideality factor, which is attributed to barrier height inhomogeneities of AlGaN/GaN HEMT. The estimated values of the series resistances (R s ) are in the range of 144.2 Ω at 223 K to 74.3 Ω at 398 K. The Φ, n, R s , G m and Schottky leakage current values are seen to be strongly temperature dependent

  4. Multiyear Program Plan for the High Temperature Materials Laboratory; FINAL

    International Nuclear Information System (INIS)

    Arvid E. Pasto

    2000-01-01

    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

  5. Temperature dependence of muonium spin exchange with O2 in the range 88 K to 478 K

    International Nuclear Information System (INIS)

    Senba, M.; Garner, D.M.; Arseneau, D.J.; Fleming, D.G.

    1984-01-01

    The authors have extended an earlier study of the spin exchange reactions of Mu with O 2 in the range 295 K to 478 K, to a low temperature region down to 88 K. From 135 K to 296 K, the spin depolarization rate constant was found to vary according to the relative velocity of the colliding species, which indicates that the spin exchange cross section of Mu-O 2 is temperature independent in this range. However, it was found that below 105 K and above 400 K, the spin depolarization rate constant tends to have stronger temperature dependences. (Auth.)

  6. Accurate dew-point measurement over a wide temperature range using a quartz crystal microbalance dew-point sensor

    Science.gov (United States)

    Kwon, Su-Yong; Kim, Jong-Chul; Choi, Buyng-Il

    2008-11-01

    Quartz crystal microbalance (QCM) dew-point sensors are based on frequency measurement, and so have fast response time, high sensitivity and high accuracy. Recently, we have reported that they have the very convenient attribute of being able to distinguish between supercooled dew and frost from a single scan through the resonant frequency of the quartz resonator as a function of the temperature. In addition to these advantages, by using three different types of heat sinks, we have developed a QCM dew/frost-point sensor with a very wide working temperature range (-90 °C to 15 °C). The temperature of the quartz surface can be obtained effectively by measuring the temperature of the quartz crystal holder and using temperature compensation curves (which showed a high level of repeatability and reproducibility). The measured dew/frost points showed very good agreement with reference values and were within ±0.1 °C over the whole temperature range.

  7. Accurate dew-point measurement over a wide temperature range using a quartz crystal microbalance dew-point sensor

    International Nuclear Information System (INIS)

    Kwon, Su-Yong; Kim, Jong-Chul; Choi, Buyng-Il

    2008-01-01

    Quartz crystal microbalance (QCM) dew-point sensors are based on frequency measurement, and so have fast response time, high sensitivity and high accuracy. Recently, we have reported that they have the very convenient attribute of being able to distinguish between supercooled dew and frost from a single scan through the resonant frequency of the quartz resonator as a function of the temperature. In addition to these advantages, by using three different types of heat sinks, we have developed a QCM dew/frost-point sensor with a very wide working temperature range (−90 °C to 15 °C). The temperature of the quartz surface can be obtained effectively by measuring the temperature of the quartz crystal holder and using temperature compensation curves (which showed a high level of repeatability and reproducibility). The measured dew/frost points showed very good agreement with reference values and were within ±0.1 °C over the whole temperature range

  8. High temperature oxidation of carbide-carbon materials of NbC-C, NbC-TiC-C systems

    International Nuclear Information System (INIS)

    Afonin, Yu.D.; Shalaginov, V.N.; Beketov, A.R.

    1981-01-01

    The effect of titanium carbide additions on the oxidation of carbide - carbon composition NbC-TiC-C in oxygen under the pressure of 10 mm Hg and in the air at atmospheric pressure in the temperature range 800-1300 deg is studied. It is shown that the region of negative temperature coefficient during oxidation in the system NbC+C is determined by the processes of sintering and polymorphous transformation. The specific character of the oxide film, formed during oxidation of Nbsub(x)Tisub(y)C+C composites is connected with non-equilibrium nature of carbide grain in its composition. Carbon gasification takes place with the formation of carbon dioxide. Composite materials, containing titanium carbide in complex carbide up to 50-83 mol. %, are the most corrosion resisting ones [ru

  9. Tensile properties and fracture mechanism of IN-100 superalloy in high temperature range

    Directory of Open Access Journals (Sweden)

    Milan T. Jovanović

    2017-06-01

    Full Text Available Tensile properties and fracture mechanism of a polycrystalline IN-100 superalloy have been investigated in the range from room temperature to 900°C. Optical microscopy (OM and transmission electron microscopy (TEM applying replica technique were used for microstructural investigation, whereas scanning electron microscopy (SEM was utilized for fracture study. High temperature tensile tests were carried out in vacuumed chamber. Results show that strength increases up to 700°C, and then sharply decreases with further increase in temperature. Elongation increases very slowly (6-7.5% till 500°C, then decreases to 4.5% at 900°C. Change in elongation may be ascribed to a change of fracture mechanism. Appearance of a great number of microvoids prevails up to 500°C resulting in a slow increase of elongation, whereas above this temperature elongation decrease is correlated with intergranular crystallographic fracture and fracture of carbides.

  10. Advanced high temperature materials for the energy efficient automotive Stirling engine

    International Nuclear Information System (INIS)

    Titran, R.H.; Stephens, J.R.

    1984-01-01

    The Stirling engine is under investigation jointly by the Department of Energy and NASA Lewis as an alternative to the internal combustion engine for automotive applications. The Stirling engine is an external combustion engine that offers the advantage of high fuel economy, low emissions, low noise, and low vibrations compared to current internal combustion automotive engines. The most critical component from a materials viewpoint is the heater head consisting of the cylinders, heating tubes, and regenerator housing. Materials requirements for the heater head include compatibility with hydrogen, resistance to hydrogen permeation, high temperature oxidation/corrosion resistance, and high temperature creep-rupture and fatigue properties. A continuing supporting materials research and technology program has identified the wrought alloys CG-27 and 12RN72, and the cast alloys XF-818 and NASAUT 4G-A1 as candidate replacements for the cobalt containing alloys used in current prototype engines. Based on the materials research program in support of the automotive Stirling engine it is concluded that manufacture of the engine is feasible from low cost iron-base alloys rather than the cobalt alloys used in prototype engines. This paper presents results of research that led to this conclusion

  11. 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.

  12. Some metallic materials and fluoride salts for high temperature applications

    International Nuclear Information System (INIS)

    Hosnedl, P.; Hron, M.; Matal, O.

    2009-01-01

    There has been a special Ni base alloy MONICR for high temperature applications in fluoride salt environments developed in the framework of the complex R and D program for the Molten Salt Reactor (MSR) - SPHINX (SPent Hot fuel Incinerator by Neutron fluX) concept development in the Czech Republic. Selected results of MONICR alloy tests and results of semi products fabrication from this alloy are discussed in the paper. The results of the structural materials tests are applied on semi-products and for the design of the testing devices as the autoclave in loop arrangement for high temperature fluoride salts applications. Material properties other Ni base alloys are compared to those of MONICR. Corrosion test results of the alloy A686 in the LiF - NaF - ZrF 4 molten salt are provided and compared to the measured values of the polarizing resistance. (author)

  13. Creep-fatigue of High Temperature Materials for VHTR: Effect of Cyclic Loading and Environment

    Energy Technology Data Exchange (ETDEWEB)

    Celine Cabet; L. Carroll; R. Wright; R. Madland

    2011-05-01

    Alloy 617 is the one of the leading candidate materials for Intermediate Heat eXchangers (IHX) of a Very High Temperature Reactor (VHTR). System start-ups and shut-downs as well as power transients will produce low cycle fatigue (LCF) loadings of components. Furthermore, the anticipated IHX operating temperature, up to 950°C, is in the range of creep so that creep-fatigue interaction, which can significantly increase the fatigue crack growth, may be one of the primary IHX damage modes. To address the needs for Alloy 617 codification and licensing, a significant creep-fatigue testing program is underway at Idaho National Laboratory. Strain controlled LCF tests including hold times up to 1800s at maximum tensile strain were conducted at total strain range of 0.3% and 0.6% in air at 950°C. Creep-fatigue testing was also performed in a simulated VHTR impure helium coolant for selected experimental conditions. The creep-fatigue tests resulted in failure times up to 1000 hrs. Fatigue resistance was significantly decreased when a hold time was added at peak stress and when the total strain was increased. The fracture mode also changed from transgranular to intergranular with introduction of a tensile hold. Changes in the microstructure were methodically characterized. A combined effect of temperature, cyclic and static loading and environment was evidenced in the targeted operating conditions of the IHX. This paper This paper reviews the data previously published by Carroll and co-workers in references 10 and 11 focusing on the role of inelastic strain accumulation and of oxidation in the initiation and propagation of surface fatigue cracks.

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

    International Nuclear Information System (INIS)

    Phadke, Sushil; DShrivastava, B; Dagaonkar, N; Mishra, Ashutosh

    2012-01-01

    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.

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

    DEFF Research Database (Denmark)

    Nikiforov, Aleksey; Petrushina, Irina; Christensen, Erik

    2011-01-01

    temperature proton exchange membrane (PEM) steam electrolysers. Steady-state voltammetry was used in combination with scanning electron microscopy and energy-dispersive X-ray spectroscopy to evaluate the stability of the mentioned materials. It was found that stainless steels were the least resistant...... 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...

  16. High temperature thermoelectric energy conversion

    International Nuclear Information System (INIS)

    Wood, C.

    1986-01-01

    Considerable advances were made in the late '50's and early early '60's in the theory and development of materials for high-temperature thermoelectric energy conversion. This early work culminated in a variety of materials, spanning a range of temperatures, with the product of the figure of merit, Z, and temperature, T, i.e., the dimensionless figure of merit, ZT, of the order of one. This experimental limitation appeared to be universal and led a number of investigators to explore the possibility that a ZT - also represents a theoretical limitation. It was found not to be so

  17. A Review of the Effects of Elevated Temperature on Concrete Materials and Structures

    International Nuclear Information System (INIS)

    Naus, D.J.; Graves, H.L. III

    2006-01-01

    Concrete's properties are more complex than those of most materials because not only is concrete a composite material whose constituents have different properties, but its properties depend upon moisture and porosity. Exposure of concrete to elevated temperature affects its mechanical and physical properties. Elements could distort and displace, and, under certain conditions, the concrete surfaces could spall due to the buildup of steam pressure. Because thermally-induced dimensional changes, loss of structural integrity, and release of moisture and gases resulting from the migration of free water could adversely affect plant operations and safety, a complete understanding of the behavior of concrete under long-term elevated-temperature exposure as well as both during and after a thermal excursion resulting from a postulated design-basis accident condition is essential for reliable design evaluations and assessments of nuclear power plant structures. As the properties of concrete change with respect to time and the environment to which it is exposed, an assessment of the effects of concrete aging is also important in performing safety evaluations. The effects of elevated temperature on Portland cement concretes and constituent materials are summarized, design codes and standards identified, and considerations for elevated temperature service noted. (authors)

  18. 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.

  19. Recrystallization kinetics of warm-rolled tungsten in the temperature range 1150-1350 °C

    DEFF Research Database (Denmark)

    Alfonso Lopez, Angel; Juul Jensen, Dorte; Luo, G.-N.

    2014-01-01

    Pure tungsten is a potential candidate material for the plasma-facing first wall and the divertor of fusion reactors. Both parts have to withstand high temperatures during service. This will alter the microstructure of the material by recovery, recrystallization and grain growth and will cause...... in the mechanical properties during annealing are quantified by Vickers hardness measurements. They are described concisely by classical kinetic models for recovery and recrystallization. The observed time spans for recrystallization and the obtained value for the activation energy of the recrystallization process...

  20. Microstructure and Property Evolution in Advanced Cladding and Duct Materials Under Long-Term and Elevated Temperature Irradiation: Modeling and Experimental Investigation

    Energy Technology Data Exchange (ETDEWEB)

    Wirth, Brian; Morgan, Dane; Kaoumi, Djamel; Motta, Arthur

    2013-12-01

    The in-service degradation of reactor core materials is related to underlying changes in the irradiated microstructure. During reactor operation, structural components and cladding experience displacement of atoms by collisions with neutrons at temperatures at which the radiation-induced defects are mobile, leading to microstructure evolution under irradiation that can degrade material properties. At the doses and temperatures relevant to fast reactor operation, the microstructure evolves by dislocation loop formation and growth, microchemistry changes due to radiation-induced segregation, radiation-induced precipitation, destabilization of the existing precipitate structure, and in some cases, void formation and growth. These processes do not occur independently; rather, their evolution is highly interlinked. Radiationinduced segregation of Cr and existing chromium carbide coverage in irradiated alloy T91 track each other closely. The radiation-induced precipitation of Ni-Si precipitates and RIS of Ni and Si in alloys T91 and HCM12A are likely related. Neither the evolution of these processes nor their coupling is understood under the conditions required for materials performance in fast reactors (temperature range 300-600°C and doses beyond 200 dpa). Further, predictive modeling is not yet possible as models for microstructure evolution must be developed along with experiments to characterize these key processes and provide tools for extrapolation. To extend the range of operation of nuclear fuel cladding and structural materials in advanced nuclear energy and transmutation systems to that required for the fast reactor, the irradiation-induced evolution of the microstructure, microchemistry, and the associated mechanical properties at relevant temperatures and doses must be understood. Predictive modeling relies on an understanding of the physical processes and also on the development of microstructure and microchemical models to describe their evolution under

  1. A broadening temperature sensitivity range with a core-shell YbEr@YbNd double ratiometric optical nanothermometer

    Science.gov (United States)

    Marciniak, L.; Prorok, K.; Francés-Soriano, L.; Pérez-Prieto, J.; Bednarkiewicz, A.

    2016-02-01

    The chemical architecture of lanthanide doped core-shell up-converting nanoparticles can be engineered to purposely design the properties of luminescent nanomaterials, which are typically inaccessible to their homogeneous counterparts. Such an approach allowed to shift the up-conversion excitation wavelength from ~980 to the more relevant ~808 nm or enable Tb or Eu up-conversion emission, which was previously impossible to obtain or inefficient. Here, we address the issue of limited temperature sensitivity range of optical lanthanide based nano-thermometers. By covering Yb-Er co-doped core nanoparticles with the Yb-Nd co-doped shell, we have intentionally combined temperature dependent Er up-conversion together with temperature dependent Nd --> Yb energy transfer, and thus have expanded the temperature response range ΔT of a single nanoparticle based optical nano-thermometer under single ~808 nm wavelength photo-excitation from around ΔT = 150 K to over ΔT = 300 K (150-450 K). Such engineered nanocrystals are suitable for remote optical temperature measurements in technology and biotechnology at the sub-micron scale.The chemical architecture of lanthanide doped core-shell up-converting nanoparticles can be engineered to purposely design the properties of luminescent nanomaterials, which are typically inaccessible to their homogeneous counterparts. Such an approach allowed to shift the up-conversion excitation wavelength from ~980 to the more relevant ~808 nm or enable Tb or Eu up-conversion emission, which was previously impossible to obtain or inefficient. Here, we address the issue of limited temperature sensitivity range of optical lanthanide based nano-thermometers. By covering Yb-Er co-doped core nanoparticles with the Yb-Nd co-doped shell, we have intentionally combined temperature dependent Er up-conversion together with temperature dependent Nd --> Yb energy transfer, and thus have expanded the temperature response range ΔT of a single nanoparticle

  2. 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...

  3. 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.

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

    International Nuclear Information System (INIS)

    Woisetschlaeger, Mischa; Lussi, Adrian; Persson, Anders; Jackowski, Christian

    2011-01-01

    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.

  5. Austenitic chromium nickel steel as standard reference material in measurement of thermal and temperature conductivity

    International Nuclear Information System (INIS)

    Binkele, L.

    1990-01-01

    A niobium-stabilized CrNi steel with the NBS designation SRM 735 is introduced as WLF standard reference material in a report by Hust and Giarratano, for the temperature range 300-1200 K and for thermal conductivities around 20 W/mk. However, its specification does not show it to be a direct member of the DIN family of CrNi steels. This report should be regarded as a continuation and supplement to the above-mentioned efforts in America. On the one hand, a solution of a possibly too-narrow specification is aimed at for the reference material, where it is important how sensitive the thermal conductivity is to changes in the chemical composition and changes of the manufacturing parameters and what accuracy can be reached for the reference values with the best measurement techniques. On the other hand, the data base should be expanded and the accuracy of the reference curve should be improved if possible. (orig./MM) [de

  6. The relationship between brightness temperature and soil moisture. Selection of frequency range for microwave remote sensing

    International Nuclear Information System (INIS)

    Rao, K.S.; Chandra, G.; Rao, P.V.N.

    1987-01-01

    The analysis of brightness temperature data acquired from field and aircraft experiments demonstrates a linear relationship between soil moisture and brightness temperature. However, the analysis of brightness temperature data acquired by the Skylab radiometer demonstrates a non-linear relationship between soil moisture and brightness temperature. In view of the above and also because of recent theoretical developments for the calculation of the dielectric constant and brightness temperature under varying soil moisture profile conditions, an attempt is made to study the theoretical relationship between brightness temperature and soil moisture as a function of frequency. Through the above analysis, the appropriate microwave frequency range for soil moisture studies is recommended

  7. Tensile testing of materials at high temperatures above 1700 °C with in situ synchrotron X-ray micro-tomography

    International Nuclear Information System (INIS)

    Haboub, Abdel; Nasiatka, James R.; MacDowell, Alastair A.; Bale, Hrishikesh A.; Cox, Brian N.; Marshall, David B.; Ritchie, Robert O.

    2014-01-01

    A compact ultrahigh temperature tensile testing instrument has been designed and fabricated for in situ x-ray micro-tomography using synchrotron radiation at the Advanced Light Source, Lawrence Berkeley National Laboratory. It allows for real time x-ray micro-tomographic imaging of test materials under mechanical load at temperatures up to 2300 °C in controlled environments (vacuum or controlled gas flow). Sample heating is by six infrared halogen lamps with ellipsoidal reflectors arranged in a confocal configuration, which generates an approximately spherical zone of high heat flux approximately 5 mm in diameter. Samples are held between grips connected to a motorized stage that loads the samples in tension or compression with forces up to 2.2 kN. The heating chamber and loading system are water-cooled for thermal stability. The entire instrument is mounted on a rotation stage that allows stepwise recording of radiographs over an angular range of 180°. A thin circumferential (360°) aluminum window in the wall of the heating chamber allows the x-rays to pass through the chamber and the sample over the full angular range. The performance of the instrument has been demonstrated by characterizing the evolution of 3D damage mechanisms in ceramic composite materials under tensile loading at 1750 °C

  8. Computer calculation of heat capacity of natural gases over a wide range of pressure and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Dranchuk, P.M. (Alberta Univ., Edmonton, AB (Canada)); Abou-Kassem, J.H. (Pennsylvania State Univ., University Park, PA (USA))

    1992-04-01

    A method is presented whereby specific heats or heat capacities of natural gases, both sweet and sour, at elevated pressures and temperatures may be made suitable to modern-day machine calculation. The method involves developing a correlation for ideal isobaric heat capacity as a function of gas gravity and pseudo reduced temperature over the temperature range of 300 to 1500 K, and a mathematical equation for the isobaric heat capacity departure based on accepted thermodynamic principles applied to an equation of state that adequately describes the behavior of gases to which the Standing and Katz Z factor correlation applies. The heat capacity departure equation is applicable over the range of 0.2 {le} Pr {le} 15 and 1.05 {le} Tr {le} 3, where Pr and Tr refer to the reduced pressure and temperature respectively. The significance of the method presented lies in its utility and adaptability to computer applications. 25 refs., 2 figs., 4 tabs.

  9. Coupled heat transfer in high temperature transporting system with semitransparent/opaque material

    International Nuclear Information System (INIS)

    Du Shenghua; Xia Xinjin

    2010-01-01

    The heat transfer model of the aerodynamic heating coupled with radiative cooling was developed. The thermal protect system includes the higher heat flux region with high temperature semitransparent material, the heat transporting channel and the lower heat flux region with metal. The control volume method was combined with the Monte Carlo method to calculate the coupled heat transfer of the transporting system, and the thermal equilibrium equation for the transporting channel was solved simultaneously. The effect of the aeroheating flux radio, the area ratio of radiative surfaces, the convective heat transfer coefficient of the heat transporting channel on the radiative surface temperature and the fluid temperature in the heat transporting channel were analyzed. The effect of radiation and conduction in the semitransparent material was discussed. The result shows that to increase the convective heat transfer coefficient in heat flux channel can enhance the heat transporting ability of the system, but the main parameter to effect on the temperature of the heat transporting system is the area ratio of radiative surfaces. (authors)

  10. Micromechanical properties of C70 single crystals in the temperature range 77-350 K

    International Nuclear Information System (INIS)

    Lubenets, S.V.; Natsik, V.D.; Fomenko, L.S.; Rusakova, A.V.; Natsik, V.D.; Osip'yan, Yu.A.; Orlov, V.I.; Sidorov, N.S.; Izotov, A.N.

    2012-01-01

    Hexagonal single crystals of C 70 up to a size down to 1-2 mm were grown which allowed for the first time to investigate their low-temperature mechanical properties. Morphology, microplasticity anisotropy and the temperature dependence of Vickers microhardness HV (T) of the C 70 crystals in the temperature range 77-350 K involving all known phase transitions have been studied with the aid of optical microscopy and microindentation. The association of the features of HV (T) dependence with orientation phase transformations has been analyzed. It is suggested that anisotropy of microplasticity in the C 70 crystals correlates with the active slip systems.

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

    Science.gov (United States)

    Garion, C.; Dufay-Chanat, L.; Koettig, T.; Machiocha, W.; Morrone, M.

    2015-12-01

    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 supporting system that has to minimise the heat inleak into the cold mass. The behaviour during a magnet quench is also presented.

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

    International Nuclear Information System (INIS)

    Garion, C; Dufay-Chanat, L; 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 supporting system that has to minimise the heat inleak into the cold mass. The behaviour during a magnet quench is also presented. (paper)

  13. "Ultra"-Fast Fracture Strength of Advanced Structural Ceramic Materials Studied at Elevated Temperatures

    Science.gov (United States)

    Choi, Sung R.; Gyekenyesi, John P.

    1999-01-01

    The accurate determination of inert strength is important in reliable life prediction of structural ceramic components. At ambient temperature, the inert strength of a brittle material is typically regarded as free of the effects of slow crack growth due to stress corrosion. Therefore, the inert strength can be determined either by eliminating active species, especially moisture, with an appropriate inert medium, or by using a very high test rate. However, at elevated temperatures, the concept or definition of the inert strength of brittle ceramic materials is not clear, since temperature itself is a degrading environment, resulting in strength degradation through slow crack growth and/or creep. Since the mechanism to control strength is rate-dependent viscous flow, the only conceivable way to determine the inert strength at elevated temperatures is to utilize a very fast test rate that either minimizes the time for or eliminates slow crack growth. Few experimental studies have measured the elevated-temperature, inert (or "ultra"-fast fracture) strength of advanced ceramics. At the NASA Lewis Research Center, an experimental study was initiated to better understand the "ultra"-fast fracture strength behavior of advanced ceramics at elevated temperatures. Fourteen advanced ceramics - one alumina, eleven silicon nitrides, and two silicon carbides - have been tested using constant stress-rate (dynamic fatigue) testing in flexure with a series of stress rates including the "ultra"-fast stress rate of 33 000 MPa/sec with digitally controlled test frames. The results for these 14 advanced ceramics indicate that, notwithstanding possible changes in flaw populations as well as flaw configurations because of elevated temperatures, the strength at 33 000 MPa/sec approached the room-temperature strength or reached a higher value than that determined at the conventional test rate of 30 MPa/sec. On the basis of the experimental data, it can be stated that the elevated-temperature

  14. 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...

  15. An integrated approach to selecting materials for fuel cladding in advanced high-temperature reactors

    Energy Technology Data Exchange (ETDEWEB)

    Rangacharyulu, C., E-mail: chary.r@usask.ca [Univ. of Saskatchewan, Saskatoon, SK (Canada); Guzonas, D.A.; Pencer, J.; Nava-Dominguez, A.; Leung, L.K.H. [Atomic Energy of Canada Limited, Chalk River, ON (Canada)

    2014-07-01

    An integrated approach has been developed for selection of fuel cladding materials for advanced high-temperature reactors. Reactor physics, thermalhydraulic and material analyses are being integrated in a systematic study comparing various candidate fuel-cladding alloys. The analyses established the axial and radial neutron fluxes, power distributions, axial and radial temperature distributions, rates of defect formation and helium production using AECL analytical toolsets and experimentally measured corrosion rates to optimize the material composition for fuel cladding. The project has just been initiated at University of Saskatchewan. Some preliminary results of the analyses are presented together with the path forward for the project. (author)

  16. Elevated Temperature Testing and Modeling of Advanced Toughened Ceramic Materials

    Science.gov (United States)

    Keith, Theo G.

    2005-01-01

    The purpose of this report is to provide a final report for the period of 12/1/03 through 11/30/04 for NASA Cooperative Agreement NCC3-776, entitled "Elevated Temperature Testing and Modeling of Advanced Toughened Ceramic Materials." During this final period, major efforts were focused on both the determination of mechanical properties of advanced ceramic materials and the development of mechanical test methodologies under several different programs of the NASA-Glenn. The important research activities made during this period are: 1. Mechanical properties evaluation of two gas-turbine grade silicon nitrides. 2) Mechanical testing for fuel-cell seal materials. 3) Mechanical properties evaluation of thermal barrier coatings and CFCCs and 4) Foreign object damage (FOD) testing.

  17. Electric breakdown of high polymer insulating materials at cryogenic temperature

    International Nuclear Information System (INIS)

    Kim, Sanhyon; Yoshino, Katsumi

    1985-01-01

    Cryogenic properties : temperature dependence of E sub(b) and effects of media upon E sub(b) were investigated on several high polymers. Temperature conditions were provided by liquid He (4.2 K), liquid N 2 (77 K) and cryogen (dry ice-methyl alcohol, 194 K). Silicone oil was used also at ambient temperature and elevated temperature. Polymer film coated with gold by vacuum evaporation was placed in cryostat, and high tension from pulse generator was applied to the film. Dielectric breakdowns were detected by oscilloscope and observed visually. The results of experiment are summerized as follow. (1) E sub(b) of film in He is affected by medium remarkably, and covering with 3-methyl pentane is effective for increasing E sub(b). (2) Temperature dependence of E sub(b) was not recognized in cryogenic temperature below liquid N 2 . (3) Temperature characteristic of E sub(b) changes considerably at the critical temperature T sub(c), and T sub(c) is dependent on material. (4) Strength against dielectric breakdown under cryogenic temperature is not affected by bridging caused by irradiation of electron beam. (5) Dielectric breakdown is thought to be caused by electronic process such as electron avalanche. Consequently, for designing insulation for the temperature below liquid He, insulation design for liquid N 2 is thought to be sufficient. However, the degradation and breakdown by mechanical stress under cryogenic temperature must be taken into consideration. (Ishimitsu, A.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Nikiforov, A.; Petruchina, I.; Christensen, E.; Bjerrum, N.J.; Tomas-Garcya, A.L. [Technical Univ. of Denmark, Lyngby (Denmark). Dept. of Chemistry, Materials Science Group

    2010-07-01

    This presentation reported on a study in which the feasibility of using different corrosion resistant stainless steels as a possible metallic bipolar plate and construction material was evaluated in terms of corrosion resistance under conditions corresponding to the conditions in high temperature proton exchange membrane (PEM) water electrolysers (HTPEMWE). PEM water electrolysis technology has been touted as an effective alternative to more conventional alkaline water electrolysis. Although the energy efficiency of this technology can be increased considerably at temperatures above 100 degrees C, this increases the demands to all the used materials with respect to corrosion stability and thermal stability. In this study, Ni-based alloys as well as titanium and tantalum samples were exposed to anodic polarization in 85 per cent phosphoric acid electrolyte solution. Tests were performed at 80 and 120 degrees C to determine the dependence of corrosion speed and working temperature. Platinum and gold plates were also tested for a comparative evaluation. Steady-state voltammetry was used along with scanning electron microscopy and energy-dispersive X-ray spectroscopy. Titanium showed the poorest corrosion resistance, while Ni-based alloys showed the highest corrosion resistance, with Inconel R 625 being the most promising alloy for the bipolar plate of an HTPEMWE. 3 refs., 1 tab., 2 figs.

  19. Composite cathode materials development for intermediate temperature solid oxide fuel cell systems

    Science.gov (United States)

    Qin, Ya

    Solid oxide fuel cell (SOFC) systems are of particular interest as electrochemical power systems that can operate on various hydrocarbon fuels with high fuel-to-electrical energy conversion efficiency. Within the SOFC stack, La0.8Sr 0.2Ga0.8Mg0.115Co0.085O3-delta (LSGMC) has been reported as an optimized composition of lanthanum gallate based electrolytes to achieve higher oxygen ionic conductivity at intermediate temperatures, i.e., 500-700°C. The electrocatalytic properties of interfaces between LSGMC electrolytes and various candidate intermediate-temperature SOFC cathodes have been investigated. Sm0.5Sr0.5CoO 3-delta (SSC), and La0.6Sr0.4Co0.2Fe 0.8O3-delta (LSCF), in both pure and composite forms with LSGMC, were investigated with regards to both oxygen reduction and evolution, A range of composite cathode compositions, having ratios of SSC (in wt.%) with LSGMC (wt.%) spanning the compositions 9:1, 8:2, 7:3, 6:4 and 5:5, were investigated to determine the optimal cathode-electrolyte interface performance at intermediate temperatures. All LSGMC electrolyte and cathode powders were synthesized using the glycine-nitrate process (GNP). Symmetrical electrochemical cells were investigated with three-electrode linear dc polarization and ac impedance spectroscopy to characterize the kinetics of the interfacial reactions in detail. Composite cathodes were found to perform better than the single phase cathodes due to significantly reduced polarization resistances. Among those composite SSC-LSGMC cathodes, the 7:3 composition has demonstrated the highest current density at the equivalent overpotential values, indicating that 7:3 is an optimal mixing ratio of the composite cathode materials to achieve the best performance. For the composite SC-LSGMC cathode/LSGMC interface, the cathodic overpotential under 1 A/cm2 current density was as low as 0.085 V at 700°C, 0.062V at 750°C and 0.051V at 800°C in air. Composite LSCF-LSGMC cathode/LSGMC interfaces were found to have

  20. The temperature dependence of the BK channel activity - kinetics, thermodynamics, and long-range correlations.

    Science.gov (United States)

    Wawrzkiewicz-Jałowiecka, Agata; Dworakowska, Beata; Grzywna, Zbigniew J

    2017-10-01

    Large-conductance, voltage dependent, Ca 2+ -activated potassium channels (BK) are transmembrane proteins that regulate many biological processes by controlling potassium flow across cell membranes. Here, we investigate to what extent temperature (in the range of 17-37°C with ΔT=5°C step) is a regulating parameter of kinetic properties of the channel gating and memory effect in the series of dwell-time series of subsequent channel's states, at membrane depolarization and hyperpolarization. The obtained results indicate that temperature affects strongly the BK channels' gating, but, counterintuitively, it exerts no effect on the long-range correlations, as measured by the Hurst coefficient. Quantitative differences between dependencies of appropriate channel's characteristics on temperature are evident for different regimes of voltage. Examining the characteristics of BK channel activity as a function of temperature allows to estimate the net activation energy (E act ) and changes of thermodynamic parameters (ΔH, ΔS, ΔG) by channel opening. Larger E act corresponds to the channel activity at membrane hyperpolarization. The analysis of entropy and enthalpy changes of closed to open channel's transition suggest the entropy-driven nature of the increase of open state probability during voltage activation and supports the hypothesis about the voltage-dependent geometry of the channel vestibule. Copyright © 2017 Elsevier B.V. All rights reserved.

  1. Proceedings of the national symposium on materials and processing: functional glass/glass-ceramics, advanced ceramics and high temperature materials

    International Nuclear Information System (INIS)

    Ghosh, A.; Sahu, A.K.; Viswanadham, C.S.; Ramanathan, S.; Hubli, R.C.; Kothiyal, G.P.

    2012-10-01

    With the development of materials science it is becoming increasingly important to process some novel materials in the area of glass, advanced ceramics and high temperature metals/alloys, which play an important role in the realization of many new technologies. Such applications demand materials with tailored specifications. Glasses and glass-ceramics find exotic applications in areas like radioactive waste storage, optical communication, zero thermal expansion coefficient telescopic mirrors, human safety gadgets (radiation resistance windows, bullet proof apparels, heat resistance components etc), biomedical (implants, hyperthermia treatment, bone cement, bone grafting etc). Advanced ceramic materials have been beneficial in biomedical applications due to their strength, biocompatibility and wear resistance. Non-oxide ceramics such as carbides, borides, silicides, their composites, refractory metals and alloys are useful as structural and control rod components in high temperature fission/ fusion reactors. Over the years a number of novel processing techniques like selective laser melting, microwave heating, nano-ceramic processing etc have emerged. A detailed understanding of the various aspects of synthesis, processing and characterization of these materials provides the base for development of novel technologies for different applications. Keeping this in mind and realizing the need for taking stock of such developments a National Symposium on Materials and Processing -2012 (MAP-2012) was planned. The topics covered in the symposium are ceramics, glass/glass-ceramics and metals and materials. Papers relevant to INIS are indexed separately

  2. Effects of temperature changes and stress loading on the mechanical and shape memory properties of thermoplastic materials with different glass transition behaviours and crystal structures.

    Science.gov (United States)

    Iijima, Masahiro; Kohda, Naohisa; Kawaguchi, Kyotaro; Muguruma, Takeshi; Ohta, Mitsuru; Naganishi, Atsuko; Murakami, Takashi; Mizoguchi, Itaru

    2015-12-01

    To investigate the effects of temperature changes and stress loading on the mechanical and shape memory properties of thermoplastic materials with different glass transition behaviours and crystal structures. Five thermoplastic materials, polyethylene terephthalate glycol (Duran®, Scheu Dental), polypropylene (Hardcast®, Scheu Dental), and polyurethane (SMP MM®, SMP Technologies) with three different glass transition temperatures (T g) were selected. The T g and crystal structure were assessed using differential scanning calorimetry and X-ray diffraction. The deterioration of mechanical properties by thermal cycling and the orthodontic forces during stepwise temperature changes were investigated using nanoindentation testing and custom-made force-measuring system. The mechanical properties were also evaluated by three-point bending tests; shape recovery with heating was then investigated. The mechanical properties for each material were decreased significantly by 2500 cycles and great decrease was observed for Hardcast (crystal plastic) with higher T g (155.5°C) and PU 1 (crystalline or semi-crystalline plastic) with lower T g (29.6°C). The Duran, PU 2, and PU 3 with intermediate T g (75.3°C for Duran, 56.5°C for PU 2, and 80.7°C for PU 3) showed relatively stable mechanical properties with thermal cycling. The polyurethane polymers showed perfect shape memory effect within the range of intraoral temperature changes. The orthodontic force produced by thermoplastic appliances decreased with the stepwise temperature change for all materials. Orthodontic forces delivered by thermoplastic appliances may influence by the T g of the materials, but not the crystal structure. Polyurethane is attractive thermoplastic materials due to their unique shape memory phenomenon, but stress relaxation with temperature changes is expected. © The Author 2015. Published by Oxford University Press on behalf of the European Orthodontic Society. All rights reserved. For

  3. Stress and Damage in Polymer Matrix Composite Materials Due to Material Degradation at High Temperatures

    Science.gov (United States)

    McManus, Hugh L.; Chamis, Christos C.

    1996-01-01

    This report describes analytical methods for calculating stresses and damage caused by degradation of the matrix constituent in polymer matrix composite materials. Laminate geometry, material properties, and matrix degradation states are specified as functions of position and time. Matrix shrinkage and property changes are modeled as functions of the degradation states. The model is incorporated into an existing composite mechanics computer code. Stresses, strains, and deformations at the laminate, ply, and micro levels are calculated, and from these calculations it is determined if there is failure of any kind. The rationale for the model (based on published experimental work) is presented, its integration into the laminate analysis code is outlined, and example results are given, with comparisons to existing material and structural data. The mechanisms behind the changes in properties and in surface cracking during long-term aging of polyimide matrix composites are clarified. High-temperature-material test methods are also evaluated.

  4. Temperature Effects on the Mechanical Properties of Candidate SNS Target Container Materials after Proton and Neutron Irradiation; TOPICAL

    International Nuclear Information System (INIS)

    Byun, T.S.

    2001-01-01

    This report presents the tensile properties of EC316LN austenitic stainless steel and 9Cr-2WVTa ferritic/martensitic steel after 800 MeV proton and spallation neutron irradiation to doses in the range 0.54 to 2.53 dpa. Irradiation temperatures were in the range 30 to 100 C. Tensile testing was performed at room temperature (20 C) and 164 C to study the effects of test temperature on the tensile properties. Test materials displayed significant radiation-induced hardening and loss of ductility due to irradiation. The EC316LN stainless steel maintained notable strain-hardening capability after irradiation, while the 9Cr-2WVTa ferritic/martensitic steel posted negative strain hardening. In the EC316LN stainless steel, increasing the test temperature from 20 C to 164 C decreased the strength by 13 to 18% and the ductility by 8 to 36%. The tensile data for the EC316LN stainless steel irradiated in spallation conditions were in line with the values in a database for 316 stainless steels for doses up to 1 dpa irradiated in fission reactors at temperatures below 200 C. However, extra strengthening induced by helium and hydrogen contents is evident in some specimens irradiated to above about 1 dpa. The effect of test temperature for the 9Cr-2WVTa ferritic/martensitic steel was less significant than for the EC316LN stainless steel. In addition, strain-hardening behaviors were analyzed for EC316LN and 316L stainless steels. The strain-hardening rate of the 316 stainless steels was largely dependent on test temperature. It was estimated that the 316 stainless steels would retain more than 1% true stains to necking at 164 C after irradiation to 5 dpa. A calculation using reduction of area (RA) measurements and stress-strain data predicted positive strain hardening during plastic instability

  5. 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.

  6. Deformation and flow of polymeric materials

    CERN Document Server

    Münstedt, Helmut

    2014-01-01

    This book describes the properties of single polymer molecules and polymeric materials and the methods how to characterize them. Molar masses, molar mass distributions and branching structure are discussed in detail. These properties are decisive for a deeper understanding of structure/properties relationships of polymeric materials. This book therefore describes and discusses them in detail. The mechanical behavior as a function of time and temperature is a key subject of the book. The authors present it on the basis of many original results they have obtained in their long research careers. They present the temperature dependence of mechanical properties of various polymeric materials in a wide temperature range: from cryogenic temperatures to the melt. Besides an extensive data collection on the transitions of various different polymeric materials, they also carefully present the physical explanations of the observed phenomena. Glass transition and melting temperatures are discussed, particularly, with the...

  7. The Science of Smart Materials

    Science.gov (United States)

    Boohan, Richard

    2011-01-01

    Over the last few decades, smart materials have become increasingly important in the design of products. Essentially, a smart material is one that has been designed to respond to a stimulus, such as a change in temperature or magnetic field, in a particular and useful way. This article looks at a range of smart materials that are relatively…

  8. 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...

  9. A new kind of shape-stabilized PCMs with positive temperature coefficient (PTC) effect

    International Nuclear Information System (INIS)

    Cheng, Wen-long; Wu, Wan-fan; Song, Jia-liang; Liu, Yi; Yuan, Shuai; Liu, Na

    2014-01-01

    Highlights: • A new kind of shape-stabilized PCMs with PTC effect is first prepared. • It provides a potential means for the thermal control of the electronic devices. • The switching temperature of the materials is about 25 °C. • The most appropriate component of the material is found out by experimental study. • The NTC effect of the new PCMs is eliminated effectively by heat treatment. - Abstract: A new kind of shape-stabilized phase change materials (PCMs) with positive temperature coefficient (PTC) effect was prepared in this paper. The materials were prepared by adding graphite powder (GP) to the paraffin/low density polyethylene (LDPE) composite and the PTC characteristic was found by adjusting the component ratio of the material. Then the physical structures and thermal properties of the materials were investigated and the effect of various GP mass fractions and paraffin/LDPE mass proportions on the PTC behavior of the materials was studied experimentally. The results showed that the switching temperature of the materials was about 25 °C (room temperature) which approached to the first phase change temperature of paraffin dispersed in the materials. The PTC behavior of the materials was the best when the GP mass fraction and the mass proportion of LDPE/paraffin were 40 wt% and 30:70, respectively. Furthermore, the negative temperature coefficient (NTC) effect of the materials could be eliminated effectively with heat treatment. This new kind of materials is different from the former PTC materials which the switching temperatures focus on high temperature ranges. It makes up for the defect of previous materials that the switching temperatures only range in high temperature rather than room temperature and provides a potential means for the thermal control of the electronic devices or other room temperature thermal control applications

  10. Transparent ceramic lamp envelope materials

    Energy Technology Data Exchange (ETDEWEB)

    Wei, G C [OSRAM SYLVANIA, 71 Cherry Hill Drive, Beverly, MA 01915 (United States)

    2005-09-07

    Transparent ceramic materials with optical qualities comparable to single crystals of similar compositions have been developed in recent years, as a result of the improved understanding of powder-processing-fabrication- sintering-property inter-relationships. These high-temperature materials with a range of thermal and mechanical properties are candidate envelopes for focused-beam, short-arc lamps containing various fills operating at temperatures higher than quartz. This paper reviews the composition, structure and properties of transparent ceramic lamp envelope materials including sapphire, small-grained polycrystalline alumina, aluminium oxynitride, yttrium aluminate garnet, magnesium aluminate spinel and yttria-lanthana. A satisfactory thermal shock resistance is required for the ceramic tube to withstand the rapid heating and cooling cycles encountered in lamps. Thermophysical properties, along with the geometry, size and thickness of a transparent ceramic tube, are important parameters in the assessment of its resistance to fracture arising from thermal stresses in lamps during service. The corrosive nature of lamp-fill liquid and vapour at high temperatures requires that all lamp components be carefully chosen to meet the target life. The wide range of new transparent ceramics represents flexibility in pushing the limit of envelope materials for improved beamer lamps.

  11. Defining the temperature range for cooking with extra virgin olive oil using Raman spectroscopy

    Science.gov (United States)

    Ahmad, Naveed; Saleem, M.; Ali, H.; Bilal, M.; Khan, Saranjam; Ullah, Rahat; Ahmed, M.; Mahmood, S.

    2017-09-01

    Using the potential of Raman spectroscopy, new findings regarding the effects of heating on extra virgin olive oil (EVOO) during frying/cooking are presented. A temperature range from 140 to 150 °C has been defined within which EVOO can be used for cooking/frying without much loss of its natural molecular composition. Raman spectra from the EVOO samples were recorded using an excitation laser at 785 nm in the range from 540 to 1800 cm-1. Due to heating, prominent variations in intensity are observed at Raman bands from 540 to 770 cm-1, 790 to 1170 cm-1 and 1267 and 1302 cm-1. The Raman bands at 1267 and 1302 cm-1 represent cis unsaturated fats and their ratio is used to investigate the effects of temperature on the molecular composition of EVOO. In addition, principal component analysis has been applied on all the groups of data to classify the heated EVOO samples at different temperatures and for different times. In addition, it has been found that use of EVOO for frying twice does not have any prominent effect on its molecular composition.

  12. Low temperature resistivity studies of SmB6: Observation of two-dimensional variable-range hopping conductivity

    Science.gov (United States)

    Batkova, Marianna; Batko, Ivan; Gabáni, Slavomír; Gažo, Emil; Konovalova, Elena; Filippov, Vladimir

    2018-05-01

    We studied electrical resistance of a single-crystalline SmB6 sample with a focus on the region of the "low-temperature resistivity plateau". Our observations did not show any true saturation of the electrical resistance at temperatures below 3 K down to 70 mK. According to our findings, temperature dependence of the electrical conduction in a certain temperature interval above 70 mK can be decomposed into a temperature-independent term and a temperature-activated term that can be described by variable-range hopping formula for two-dimensional systems, exp [ -(T0 / T) 1 / 3 ]. Thus, our results indicate importance of hopping type of electrical transport in the near-surface region of SmB6.

  13. Analysis and description of high temperature alloy data and their representation in the high temperature materials data bank of the Joint Research Centre

    International Nuclear Information System (INIS)

    Krefeld, R.; Kroeckel, H.; Fattori, G.; Maurandy, C.

    1985-01-01

    In the frame of the high temperature materials programme the JRC has set up a pilot data bank for mechanical and corrosion properties of materials for high temperature application in energy conversion and chemical systems. The scope of the data bank content embraces mechanical properties and corrosion tests with emphasis on 600 to 1000 0 C test temperature and C-O-H type test environments. The basic information on materials properties obtained by test is analysed and the data items and their structure are described. The logical structure of the 250 data items involved and their organization in the data bank by file and record using ADABAS dbms is presented. The design is discussed with respect to its adaptability to changes in the scope of data content and to its versatile data access resulting in easy handling of complex structured queries which represent the interest of materials scientists and engineers as well as those of non-specialist users. (orig.)

  14. Dynamic mechanical behaviour and dislocation substructure evolution of Inconel 718 over wide temperature range

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Woei-Shyan, E-mail: wslee@mail.ncku.edu.tw [Department of Mechanical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China); Lin, Chi-Feng [National Center for High-Performance Computing, Hsin-Shi Tainan County 744, Taiwan (China); Chen, Tao-Hsing [Department of Mechanical Engineering, National Kaohsiung University of Applied Sciences, Kaohsiung 807, Taiwan (China); Chen, Hong-Wei [Department of Mechanical Engineering, National Cheng Kung University, Tainan 701, Taiwan (China)

    2011-07-25

    A compressive split-Hopkinson pressure bar and transmission electron microscope (TEM) are used to investigate the mechanical behaviour and microstructural evolution of Inconel 718 at strain rates ranging from 1000 to 5000 s{sup -1} and temperatures between -150 and 550 deg. C. The results show that the flow stress increases with an increasing strain rate or a reducing temperature. The strain rate effect is particularly pronounced at strain rates greater than 3000 s{sup -1} and a deformation temperature of -150 deg. C. A significant thermal softening effect occurs at temperatures between -150 and 25 deg. C. The microstructural observations reveal that the strengthening effect in deformed Inconel 718 alloy is a result primarily of dislocation multiplication. The dislocation density increases with increasing strain rate, but decreases with increasing temperature. By contrast, the dislocation cell size decreases with increasing strain rate, but increases with increasing temperature. It is shown that the correlation between the flow stress, the dislocation density and the dislocation cell size is well described by the Bailey-Hirsch constitutive equations.

  15. High temperature resistant materials and structural ceramics for use in high temperature gas cooled reactors and fusion plants

    International Nuclear Information System (INIS)

    Nickel, H.

    1992-01-01

    Irrespective of the systems and the status of the nuclear reactor development lines, the availability, qualification and development of materials are crucial. This paper concentrates on the requirements and the status of development of high temperature metallic and ceramic materials for core and heat transferring components in advanced HTR supplying process heat and for plasma exposed, high heat flux components in Tokamak fusion reactor types. (J.P.N.)

  16. Radon diffusion through sandy construction materials: effect of temperature and grain size

    International Nuclear Information System (INIS)

    Narula, A.K.; Goyal, S.K.; Jain, Ravinder; Kant, Krishan; Yadav, Mani Kant; Chauhan, R.P.; Chakarvarti, S.K.

    2013-01-01

    Radon appears mainly by diffusion process from the point of origin, say, under ground soil and building materials used in construction of house following alpha decay of radium. The radon diffusion through different building construction materials can be compared by calculating radon diffusion coefficient for them. In the present work, we studied the effect of temperature and grain size on radon diffusion of coarse sand as construction material. The coarse sand was collected from Yamuna river bed, originated from Himalayas. For this study, a steel pipe of diameter 10 cm and length 30 cm., divided into four sectors of equal size, was filled in different sectors with different grain sized (800, 600 and 425 μm) sand as building construction material. A number LR-115 type-II particle track detectors were placed with inter-detector distance of 10 cm in the sectorial compartments. The bottom end of steel pipe assembly was fixed with a radon chamber containing radon source with upper end sealed with a cap. The whole arrangement was then placed into a sand-clay pipe wrapped around by a controlled heating filament, resulting into temperature variations from 25℃ to 60℃. After 100 days interval, the detectors were retrieved processed, and the α - tracks counted for the calculation of radon concentration. It is observed that the radon diffusion coefficient increases with the increase in temperature and decreases with decrease in grain size of the coarse sand. (author)

  17. 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 cost and large-area fabrication, make MFSOTE materials possess promising applications in e-skin and health-monitoring elements.

  18. 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.

  19. Grain-boundary engineering applied to grain growth in a high temperature material

    International Nuclear Information System (INIS)

    Huda, Z.

    1993-01-01

    Crystallography of grain boundaries are determined for a high temperature material, before and after grain growth processes, so as to study the induction of special properties useful for application in components of a gas-turbine engine. The philosophy of grain-boundary engineering is applied to grain growth in APK-6, a powder formed nickel-base superalloy so as to establish the possible structure/property relationships. The alloy in the as received condition is shown to possess a strong texture and contained coincident site lattices (CSL) boundaries with most boundaries having sigma values in the range of 3 > sigma > 25. A normal grain-growth heat treatment result in a good population of low angle grain boundaries, and drastically reduces the proportion of CSL boundaries. A strong [011] annealing texture is observed after an intermediate grain growth; most grain boundaries, here, tend to be high angle indicating a possibility of possessing special properties. (author)

  20. 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)

  1. Raman spectroscopic characterization of CH4 density over a wide range of temperature and pressure

    Science.gov (United States)

    Shang, Linbo; Chou, I-Ming; Burruss, Robert; Hu, Ruizhong; Bi, Xianwu

    2014-01-01

    The positions of the CH4 Raman ν1 symmetric stretching bands were measured in a wide range of temperature (from −180 °C to 350 °C) and density (up to 0.45 g/cm3) using high-pressure optical cell and fused silica capillary capsule. The results show that the Raman band shift is a function of both methane density and temperature; the band shifts to lower wavenumbers as the density increases and the temperature decreases. An equation representing the observed relationship among the CH4 ν1 band position, temperature, and density can be used to calculate the density in natural or synthetic CH4-bearing inclusions.

  2. Range-wide latitudinal and elevational temperature gradients for the world's terrestrial birds: implications under global climate change.

    Directory of Open Access Journals (Sweden)

    Frank A La Sorte

    Full Text Available Species' geographical distributions are tracking latitudinal and elevational surface temperature gradients under global climate change. To evaluate the opportunities to track these gradients across space, we provide a first baseline assessment of the steepness of these gradients for the world's terrestrial birds. Within the breeding ranges of 9,014 bird species, we characterized the spatial gradients in temperature along latitude and elevation for all and a subset of bird species, respectively. We summarized these temperature gradients globally for threatened and non-threatened species and determined how their steepness varied based on species' geography (range size, shape, and orientation and projected changes in temperature under climate change. Elevational temperature gradients were steepest for species in Africa, western North and South America, and central Asia and shallowest in Australasia, insular IndoMalaya, and the Neotropical lowlands. Latitudinal temperature gradients were steepest for extratropical species, especially in the Northern Hemisphere. Threatened species had shallower elevational gradients whereas latitudinal gradients differed little between threatened and non-threatened species. The strength of elevational gradients was positively correlated with projected changes in temperature. For latitudinal gradients, this relationship only held for extratropical species. The strength of latitudinal gradients was better predicted by species' geography, but primarily for extratropical species. Our findings suggest threatened species are associated with shallower elevational temperature gradients, whereas steep latitudinal gradients are most prevalent outside the tropics where fewer bird species occur year-round. Future modeling and mitigation efforts would benefit from the development of finer grain distributional data to ascertain how these gradients are structured within species' ranges, how and why these gradients vary among

  3. 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.)

  4. 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.

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

    International Nuclear Information System (INIS)

    2015-01-01

    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.

  6. Effect and control on temperature measurement accuracy of the fiber- optic colorimeter by emissivity of different temperatures

    Science.gov (United States)

    Liu, Yu-fang; Han, Xin; Shi, De-heng

    2008-03-01

    Based on the Kirchhoff's Law, a practical dual-wavelength fiber-optic colorimeter, with the optimal work wavelength centered at 2.1 μm and 2.3 μm is presented. The effect of the emissivity on the precision of the measured temperature has been explored under various circumstances (i.e. temperature, wavelength) and for different materials. In addition, by fitting several typical material emissivity-temperature dependencies curves, the influence of the irradiation (radiant flux originating from the surroundings) and the surface reflected radiation on the temperature accuracy is studied. The results show that the calibration of the measured temperature for reflected radiant energy is necessary especially in low target temperature or low target emissivity, and the temperature accuracy is suitable for requirements in the range of 400-1200K.

  7. Ten years of high temperature materials research at PSI - An overview paper

    International Nuclear Information System (INIS)

    Pouchon, Manuel A.; Chen Jiachao

    2014-01-01

    At the Paul Scherrer Institute high temperature materials research for advanced nuclear systems is performed since a decade, formerly by the HT-Mat group and today the advanced nuclear materials (ANM) group. In this paper the activities being conducted in this time are summarized. This includes the study of three major materials classes, intermetallics with a titanium alluminide, nanostructured steel with different ODS candidates, and ceramics with silicon carbide composites. The studies being performed include experimental work, studying the mechanical behavior as function of irradiation exposure and temperature, including also in situ studies such as the creep under ion beam irradiation plus miniaturized samples such as pillars. The microstructure changes as function of these exposures, using electron microscopy on one hand and advanced beamline techniques on the other hand. Part of the finding lead to the development of new damage mechanism models. Complementary to the experimental approach, modelling activities were conducted to understand the basics of the damage mechanisms. The research lead to a consolidation of the candidate materials to the most promising ones, namely the oxide dispersion strengthened steels (ODS) and the silicon carbide based composite materials. The research lead to new, relevant data such as the creep behavior of material under extreme reactor conditions, the embitterment mechanism in advanced materials, and much more. A sketch of the research philosophy and an outline of the main results will be given. (author)

  8. Research of resonant losses of ultrasonic sound in the deformed single crystals in temperature range 77...300 K

    International Nuclear Information System (INIS)

    Petchenko, A.M.; Petchenko, G.A.

    2007-01-01

    The damped dislocation resonance in preliminary deformed up to 1 % single crystals KBr was investigated. The measurements of a frequency dependence of a dislocation damping decrement of ultrasonic sound were conducted in range of frequencies 7,5...217,5 MHz and temperature range 77...300 K. From the analysis of frequency spectrums the temperature course of a coefficient of phonon viscosity B was determined, which is agreed both with the theory and experimental literary data. The influencing temperature changes of length of a dislocation segment on parameters of a resonant maximum and dynamic drag of dislocations by phonons was revealed and analyzed

  9. Ductility of brazing assemblies with high-temperature materials

    International Nuclear Information System (INIS)

    Colbus, J.; De Paoli, A.

    1977-01-01

    Brazing assemblies with the high temperature materials X8CrNiNb1613, X12CrNiMo12 and X8NiCrAlTiMo7020 have been produced using different solder metals. These brazing assemblies have been studied with the emphasis on the interrelation between microstructure and ductility. Besides the ordinary impact bend tests of notched and unnotched brazed joints, the impact bend tests of unnotched brazed joints with drawing of a Strength-Way-Diagram have been added for better results. (GSC) [de

  10. Modern filaments for composite materials

    International Nuclear Information System (INIS)

    Krivelli-Viskonti, I.

    1982-01-01

    Analysis of modern state and ways to improve properties of different filaments for the forecast of the filament application in composite materials has been conducted. In the near future as before the greatest attention will be paid to fibre glass, as this material is widely used in the reinforcing of organic matrices. Carbon and kevlar filaments are the most prospective ones. For the service at medium, high or superhigh temperatures selection of matrix material is more significant than selection of filament. Organic matrices can not be used at temperatures > 250 deg C: this is already the range of metal matrix application. Though at temperatures above room one many filaments can be used, boron filaments and metal wire are the only reinforcing materials, inspite of the fact that carbon filaments are successfully used for metal matrix reinforcing. At very high temperatures only carbon filaments or silicon carbide ones can be used, but their cost is very high and besides economical problems there are many difficulties of technical character

  11. Intermediate Temperature Proton Conductors – Why and How

    OpenAIRE

    Li, Qingfeng; Aili, David; Jensen, Jens Oluf; Cleemann, Lars Nilausen

    2016-01-01

    The current technologies of fuel cells and electrolzers are based on ionic conducting electrolyte materials exclusively operational either in the low (20 - 200ºC) or high (600 - 1000ºC) temperature ranges. The intermediate temperature window, especially between 200 and 400 ºC, is still only represented by early fundamental material research for ionic electrolytes. Such materials, most likely based on proton conductors, are expected to bring a new generation of the technologies: fuel cells by ...

  12. Long-term strength of claddings made of E110 in the temperature range of 400-570 degrees C

    International Nuclear Information System (INIS)

    Kobylyansky, G.; Shamardin, V.; Eremin, S.

    2003-01-01

    This paper presents the data on the initial stage of the in-sight into the mechanism of long-term strength of spent fuel rod claddings in the temperature range 400-570 0 C and also their comparison with corresponding mechanism of irradiated in the inert environment specimens and unirradiated ones. A set of test results in the temperature range 400-570 0 C of non-irradiated and irradiated in BOR-60 specimens and also of the WWER-1000 fuel element claddings irradiated up to a burnup of 29-47 MWd/kgU is approximated by Larson-Miller parametric dependence in the first approximation that allows the long-term strength data to be extrapolated and interpolated onto the unknown value regions of stress, temperature and time. The time before damage of the fuel element claddings irradiated up to ∼ 29MWd/kgU in the temperature range 540-570 0 C is higher than that of non-irradiated tubular specimens and irradiated ones up to fast neutron fluence (1-2)x10 22 cm -2 (E >0.1 MeV). With temperature decreasing to 673 K, the long-term strength of the claddings irradiated up to ∼ 47 MWd/kgU is lower than it can be expected from the extrapolation of high-temperature data obtained with the irradiated specimens. Now, the bulk of experimental data on the long-term strength of the claddings made of E110 alloy makes it possible to provide only preliminary estimation for the validation of parameters typical of the deviation from the normal operation conditions; emergencies and accidental situations; dry and wet storage and also transportation. The experiments should be continued to accumulate missing data, in particular, tests of fuel element claddings irradiated up to high burnup at temperatures ranging 300-400 0 C and stresses, which are significantly lower than the yield stress

  13. Solvothermal method as a green chemistry solution for micro-encapsulation of phase change materials for high temperature thermal energy storage

    Directory of Open Access Journals (Sweden)

    Tudor Albert Ioan

    2018-01-01

    Full Text Available Thermal energy storage systems using phase change materials (PCMs as latent heat storage are one of the main challenges at European level in improving the performances and efficiency of concentrated solar power energy generation due to their high energy density. PCM with high working temperatures in the temperature range 300–500 °C are required for these purposes. However their use is still limited due to the problems raised by the corrosion of the majority of high temperature PCMs and lower thermal transfer properties. Micro-encapsulation was proposed as one method to overcome these problems. Different micro-encapsulation methods proposed in the literature are presented and discussed. An original process for the micro-encapsulation of potassium nitrate as PCM in inorganic zinc oxide shells based on a solvothermal method followed by spray drying to produce microcapsules with controlled phase composition and distribution is proposed and their transformation temperatures and enthalpies measured by differential scanning calorimetry are presented.

  14. Solvothermal method as a green chemistry solution for micro-encapsulation of phase change materials for high temperature thermal energy storage

    Science.gov (United States)

    Tudor, Albert Ioan; Motoc, Adrian Mihail; Ciobota, Cristina Florentina; Ciobota, Dan. Nastase; Piticescu, Radu Robert; Romero-Sanchez, Maria Dolores

    2018-05-01

    Thermal energy storage systems using phase change materials (PCMs) as latent heat storage are one of the main challenges at European level in improving the performances and efficiency of concentrated solar power energy generation due to their high energy density. PCM with high working temperatures in the temperature range 300-500 °C are required for these purposes. However their use is still limited due to the problems raised by the corrosion of the majority of high temperature PCMs and lower thermal transfer properties. Micro-encapsulation was proposed as one method to overcome these problems. Different micro-encapsulation methods proposed in the literature are presented and discussed. An original process for the micro-encapsulation of potassium nitrate as PCM in inorganic zinc oxide shells based on a solvothermal method followed by spray drying to produce microcapsules with controlled phase composition and distribution is proposed and their transformation temperatures and enthalpies measured by differential scanning calorimetry are presented.

  15. The enthalpy of solid scandium in the temperature range 406 - 1812 K

    International Nuclear Information System (INIS)

    Lyapunov, K.M.; Baginskij, A.V.; Stankus, S.V.

    2001-01-01

    Enthalpy of pure scandium was measured on massive calorimeter in the range from 406 to 1812 K by mixing method. The enthalpy of face centered close cubic lattice - body centered cubic lattice transformation is equal to ΔH t 4068 J/mol. Obtained value within the limits of error is compatible with the results given earlier (4009 J/mol). The dependence of the middle specific heat of scandium C p (T) on the temperature was shown in correlation with the results of other works. The results of the conducted experiments reinforce the conclusion made earlier about an absence (or a little) in the decomposition of an anharmonic component of the oscillation specific heat of scandium C p a (T) members proportional to the first or the second degrees of temperature [ru

  16. Low temperature thermal conductivities of glassy carbons

    International Nuclear Information System (INIS)

    Anderson, A.C.

    1979-01-01

    The thermal conductivity of glassy carbon in the temperature range 0.1 to 100 0 K appears to depend only on the temperature at which the material was pyrolyzed. The thermal conductivity can be related to the microscopic structure of glassy carbon. The reticulated structure is especially useful for thermal isolation at cryogenic temperatures

  17. Principal physical mechanisms of material creep resistance and rupture at elevated temperatures

    International Nuclear Information System (INIS)

    Krishtal, M.A.

    1977-01-01

    Mechanisms of creep and long-term failure of refractory materials at different temperatures and stress levels are considered. At high temperatures and low stresses the diffusion (vacancial) mechanism is observed. Temperatures being low and stresses sufficiently high, dislocation mechanism involving avalanche dislocation break-off is manifested. Intermediate conditions provide other mechanisms, i.e. dislocation glide, dislocation climbing, grain-boundary and sub-grain-boundary mechanisms. Quantitative relationships between creep rate and some structural and kinetic parameters are discussed. Account of the creep mechanism is necessary when selecting methods for strengthening of alloys

  18. 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

  19. High temperature metallic materials for gas-cooled reactors

    International Nuclear Information System (INIS)

    1989-06-01

    The Specialists' Meeting was organized in conjunction with an earlier meeting on this topic held in Vienna, Austria, 1981, which provided for a comprehensive review of the status of materials development and testing at that time and for a description of test facilities. This meeting provided an opportunity (1) to review and discuss the progress made since 1981 in the development, testing and qualification of high temperature metallic materials, (2) to critically assess results achieved, and (3) to give directions for future research and development programmes. In particular, the meeting provided a form for a close interaction between component designers and materials specialists. The meeting was attended by 48 participants from France, People's Republic of China, Federal Republic of Germany, Japan, Poland, Switzerland, United Kingdom, USSR and USA presenting 22 papers. The technical part of the meeting was subdivided into four technical sessions: Components Design and Testing - Implications for Materials (4 papers); Microstructure and Environmental Compatibility (4 papers); Mechanical Properties (9 papers); New Alloys and Developments (6 papers). At the end of the meeting a round table discussion was organized in order to summarize the meeting and to make recommendations for future activities. This volume contains all papers presented at the meeting. A separate abstract was prepared for each of these papers. Refs, figs and tabs

  20. High Temperature Thermoelectric Properties of ZnO Based Materials

    DEFF Research Database (Denmark)

    Han, Li

    of the dopants and dopant concentrations, a large power factor was obtainable. The sample with the composition of Zn0.9Cd0.1Sc0.01O obtained the highest zT ∼0.3 @1173 K, ~0.24 @1073K, and a good average zT which is better than the state-of-the-art n-type thermoelectric oxide materials. Meanwhile, Sc-doped Zn......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 Zn......O. 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...

  1. Range of monthly mean hourly land surface air temperature diurnal cycle over high northern latitudes

    Science.gov (United States)

    Wang, Aihui; Zeng, Xubin

    2014-05-01

    Daily maximum and minimum temperatures over global land are fundamental climate variables, and their difference represents the diurnal temperature range (DTR). While the differences between the monthly averaged DTR (MDTR) and the range of monthly averaged hourly temperature diurnal cycle (RMDT) are easy to understand qualitatively, their differences have not been quantified over global land areas. Based on our newly developed in situ data (Climatic Research Unit) reanalysis (Modern-Era Retrospective analysis for Research and Applications) merged hourly temperature data from 1979 to 2009, RMDT in January is found to be much smaller than that in July over high northern latitudes, as it is much more affected by the diurnal radiative forcing than by the horizontal advection of temperature. In contrast, MDTR in January is comparable to that in July over high northern latitudes, but it is much larger than January RMDT, as it primarily reflects the movement of lower frequency synoptic weather systems. The area-averaged RMDT trends north of 40°N are near zero in November, December, and January, while the trends of MDTR are negative. These results suggest the need to use both the traditional MDTR and RMDT suggested here in future observational and modeling studies. Furthermore, MDTR and its trend are more sensitive to the starting hour of a 24 h day used in the calculations than those for RMDT, and this factor also needs to be considered in model evaluations using observational data.

  2. NATO Advanced Research Workshop on Smart Materials for Ranging Systems

    CERN Document Server

    Franse, Jaap; Sirenko, Valentyna

    2006-01-01

    The problem of determining the location of an object (usually called ranging) attracts at present much attention in different areas of applications, among them in ecological and safety devices. Electromagnetic waves along with sound waves are widely used for these purposes. Different aspects of materials with specific magnetic, electric and elastic properties are considered in view of potential application in the design and manufacturing of smart materials. Progress is reported in the fabrication and understanding of in-situ formation and characterization of solid state structures with specified properties. Attention is paid to the observation and study of the mobility of magnetic structures and of the kinetics of magnetic ordering transitions. Looking from a different perspective, one of the outcomes of the ARW is the emphasis on the important role that collective phenomena (like spin waves in systems with a magnetically ordered ground state, or critical currents in superconductors) could play at the design ...

  3. Study of plastic deformation peculiarities in CdS single crystals within the temperature range of 25 to 300 deg C

    International Nuclear Information System (INIS)

    Bulatova, T.M.

    1990-01-01

    By the method of stress relaxation dependences of platic deformation rate on effective strain in CdS monocrystals for the temperatures of 25-300 deg C both in the darkness and in the light are obtained. In the range of the temperatures up to 150 deg C deformation activation energy is determined, which correlates with the value of point defect diffusion activation energy in the crystal. Anomalous temperature dependence of plastic deformation rate, i.e. its decrease with the temperature increase in the range of 150-300 deg C is detected

  4. Polyamide–thallium selenide composite materials via temperature and pH controlled adsorption–diffusion method

    International Nuclear Information System (INIS)

    Ivanauskas, Remigijus; Samardokas, Linas; Mikolajunas, Marius; Virzonis, Darius; Baltrusaitis, Jonas

    2014-01-01

    Graphical abstract: Single phase polyamide–thallium selenide hybrid functional materials were synthesized for solar energy conversion. - Highlights: • Thallium selenide–polyamide composite materials surfaces synthesized. • Mixed phase composition confirmed by XRD. • Increased temperature resulted in a denser surface packing. • Urbach energies correlated with AFM showing decreased structural disorder. • Annealing in N 2 at 100 °C yielded a single TlSe phase. - Abstract: Composite materials based on III–VI elements are promising in designing efficient photoelectronic devices, such as thin film organic–inorganic solar cells. In this work, TlSe composite materials were synthesized on a model polymer polyamide using temperature and pH controlled adsorption–diffusion method via (a) selenization followed by (b) the exposure to the group III metal (Tl) salt solution and their surface morphological, chemical and crystalline phase information was determined with particular focus on their corresponding structure–optical property relationship. XRD analysis yielded a complex crystalline phase distribution which correlated well with the optical and surface morphological properties measured. pH 11.3 and 80 °C yielded well defined, low structural disorder composite material surface. After annealing in N 2 at 100 °C, polycrystalline PA-Tl x Se y composite materials yielded a single TlSe phase due to the enhanced diffusion and reaction of thallium ions into the polymer. The method described here can be used to synthesize variety of binary III–VI compounds diffused into the polymer at relatively low temperatures and low overall cost, thus providing for a flexible synthesis route for novel composite solar energy harvesting materials

  5. Study on low cycle fatigue behavior of two titanium alloy materials with elevated temperature effects

    International Nuclear Information System (INIS)

    Cai Lixun; Sun Yafang; Wang Li; Huang Shuzhen

    2000-01-01

    A serial of tensional and low cycle fatigue tests for two titanium alloy materials:T42NG and T225NG under room temperature and 350 degree C elevated temperature are carried out. Based on the test results, four monotonic constitutive relationships between stress and strain and four relationships between life Nf and strain amplitude controlled are given. By three ratio λ σ , λ Δσ and λ Nf of the materials related to the elevated temperature, systematical investigations about the influence of the elevated temperature on monotonic tensional intensity, cyclic intensity and fatigue life are performed. According to the important rule opened out that it exists a linearity relationship between the ratio λ Nf and strain amplitude Δε/2, the author present a λ-M-C model for predicting the fatigue life of a exponential material under R= -1 and an elevated temperature. To get the λ-M-C model, the authors give available discussion about the method simplified test and regression. The authors know from test results that T42NG steel has better fatigue and tensional behaviors than those of T225NG steel

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

    International Nuclear Information System (INIS)

    Sonder, E.

    1976-01-01

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

  7. Thermal characteristics of shape-stabilized phase change material wallboard with periodical outside temperature waves

    International Nuclear Information System (INIS)

    Zhou, Guobing; Yang, Yongping; Wang, Xin; Cheng, Jinming

    2010-01-01

    Thermal characteristics of shape-stabilized phase change material (SSPCM) wallboard with sinusoidal temperature wave on the outer surface were investigated numerically and compared with traditional building materials such as brick, foam concrete and expanded polystyrene (EPS). One-dimensional enthalpy equation under convective boundary conditions was solved using fully implicit finite-difference scheme. The simulation results showed that the SSPCM wallboard presents distinct characteristics from other ordinary building materials. Phase transition keeping time of inner surface and decrement factor were applied to analyze the effects of PCM thermophysical properties (melting temperature, heat of fusion, phase transition zone and thermal conductivity), inner surface convective heat transfer coefficient and thickness of SSPCM wallboard. It was found that melting temperature is one important factor which influences both the phase transition keeping time and the decrement factor; for a certain outside temperature wave, there exist critical values of latent heat of fusion and thickness of SSPCM above which the phase transition keeping time or the decrement factor are scarcely influenced; thermal conductivity of PCM and inner surface convective coefficient have little effect on the phase transition keeping time but significantly influence the decrement factor; and the phase transition zone leads to small fluctuations of the original flat segment of inner surface temperature line. The results aim to be useful for the selection of SSPCMs and their applications in passive solar buildings.

  8. Effect of microstructure on low temperature electrochemical properties of LiFePO4/C cathode material

    International Nuclear Information System (INIS)

    Zhao, Nannan; Zhi, Xiaoke; Wang, Li; Liu, Yanhui; Liang, Guangchuan

    2015-01-01

    Graphical abstract: The low temperature performance of Li-ion batteries and LiFePO 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 2 O 4 , LiNi 1/3 Co 1/3 Mn 1/3 O 2 and LiFePO 4 /C as cathode materials. The low temperature performance results indicate the LiFePO 4 /C microstructure is the main factor influencing the low temperature performance of LiFePO 4 . A new LiFePO 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 4 /C composite was discussed. • Cathode material mainly decided the low temperature performance of Li-ion battery. • LiFePO 4 /C microstructure mainly affects its low temperature performance. • Pomegranate-like spherical structure LiFePO 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 2 O 4 , LiNi 1/3 Co 1/3 Mn 1/3 O 2 , and LiFePO 4 /C as the cathode, respectively, at −20 °C. LiFePO 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 indicate that the microstructure of LiFePO 4 /C is a key factor determining the low-temperature

  9. Infinite-range Heisenberg model and high-temperature superconductivity

    Science.gov (United States)

    Tahir-Kheli, Jamil; Goddard, William A., III

    1993-11-01

    A strongly coupled variational wave function, the doublet spin-projected Néel state (DSPN), is proposed for oxygen holes in three-band models of high-temperature superconductors. This wave function has the three-spin system of the oxygen hole plus the two neighboring copper atoms coupled in a spin-1/2 doublet. The copper spins in the neighborhood of a hole are in an eigenstate of the infinite-range Heisenberg antiferromagnet (SPN state). The doublet three-spin magnetic polaron or hopping polaron (HP) is stabilized by the hopping terms tσ and tτ, rather than by the copper-oxygen antiferromagnetic coupling Jpd. Although, the HP has a large projection onto the Emery (Dg) polaron, a non-negligible amount of doublet-u (Du) character is required for optimal hopping stabilization. This is due to Jdd, the copper-copper antiferromagnetic coupling. For the copper spins near an oxygen hole, the copper-copper antiferromagnetic coupling can be considered to be almost infinite ranged, since the copper-spin-correlation length in the superconducting phase (0.06-0.25 holes per in-plane copper) is approximately equal to the mean separation of the holes (between 2 and 4 lattice spacings). The general DSPN wave function is constructed for the motion of a single quasiparticle in an antiferromagnetic background. The SPN state allows simple calculations of various couplings of the oxygen hole with the copper spins. The energy minimum is found at symmetry (π/2,π/2) and the bandwidth scales with Jdd. These results are in agreement with exact computations on a lattice. The coupling of the quasiparticles leads to an attraction of holes and its magnitude is estimated.

  10. An Investigation of Porous Structure of TiNi-Based SHS-Materials Produced at Different Initial Synthesis Temperatures

    Science.gov (United States)

    Khodorenko, V. N.; Anikeev, S. G.; Kokorev, O. V.; Yasenchuk, Yu. F.; Gunther, V. É.

    2018-02-01

    An investigation of structural characteristics and behavior of TiNi-based pore-permeable materials manufactured by the methods of selfpropagating high-temperature synthesis (SHS) at the initial synthesis temperatures T = 400 and 600°C is performed. It is shown that depending on the temperature regime, the resulting structure and properties of the material can differ. It is found out that the SHS-material produced at the initial synthesis temperature T = 400°C possesses the largest number of micropores in the pore wall surface structure due to a high phase inhomogeneity of the alloy. The regime of structure optimization of the resulting materials is described and the main stages of formation of the pore wall microporous surfaces are revealed. It is demonstrated that after optimization of the surface structure of a TiNi-based fine-pore alloy by its chemical etching, the fraction of micropores measuring in size less than 50 nm increased from 59 to 68%, while the number of pores larger than 1 μm increased twofold from 11 to 22%. In addition, peculiar features of interaction between certain cell cultures with the surface of the SHS-material manufactured at different initial synthesis temperatures are revealed. It is found out that the dynamics of the cell material integration depends on the pore wall surface morphology and dimensions of macropores.

  11. High Temperature Strength of Oxide Dispersion Strengthened Aluminium

    DEFF Research Database (Denmark)

    Clauer, A.H.; Hansen, Niels

    1984-01-01

    constant (except for the material with the lowest oxide content). The high temperature values of the modulus-corrected yield stresses are approximately two-thirds of the low temperature value. During high temperature creep, there is a definite indication of a threshold stress. This threshold stress......The tensile flow stress of coarse-grained dispersion strengthened Al-Al2O3 materials were measured as a function of temperature (77–873 K) and volume fraction (0.19-0.92 vol.%) of aluminium oxide. For the same material, the creep strength was determined as a function of temperature in the range 573......–873 K. The modulus-corrected yield stress (0.01 offset) is found to be temperature independent at low temperature (195–472 K). Between 473 and 573 K, the yield stress starts to decrease with increasing temperature. At high temperatures (573–873 K), the modulus-corrected yield stress is approximately...

  12. Thermophysical characterization tools and numerical models for high temperature thermo-structural composite materials

    International Nuclear Information System (INIS)

    Lorrette, Ch.

    2007-04-01

    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)

  13. Evolution of microstructure in 100Cr6 steel after cooling from a thixoforming temperature to bainitic transformation ranges

    Energy Technology Data Exchange (ETDEWEB)

    Rogal, Łukasz, E-mail: l.rogal@imim.pl [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta Street, 30-059 Krakow (Poland); Korpala, Grzegorz [Institut für Metallformung, TU Bergakademie Freiberg, 4 Bernhard-von-Cotta-Straße, 09596 Freiberg (Germany); Dutkiewicz, Jan [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta Street, 30-059 Krakow (Poland)

    2015-01-29

    A new concept for the isothermal heat treatment of thixo-elements, consisting of controlled cooling from a semi-solid metal processing (SSM) range, was proposed. 100Cr6 steel (0.97% C, 1.4% Cr, 0.4% Si, 0.4% Mn bal. Fe) after forging was used as the starting material. The DSC analysis was used to determine the liquid phase fraction vs temperature in the solidus–liquidus range. The temperatures and kinetics of bainite transformation after cooling the steel in the semi-solid state were calculated based on the Chester and Bhadeshia models. The steel was heated up to 1425 °C in order to obtain about 25% of the liquid fraction. Then it was cooled in oil at three different temperatures: 135 °C, 235 °C and 335 °C, at which the samples were held for 5 h. The microstructure of the samples annealed at 135 °C consisted of globular grains (the average size of 323 µm), where coarse needles of martensite were observed. They were surrounded by an eutectic mixture of chemical composition different from that of the globular grains. The electron diffraction pattern (SAEDP) showed reflections from α′-Fe and from Fe{sub 3}C carbides. The X-ray diffraction confirmed the presence of martensite, austenite and carbides to the amount of 74.5%, 22% and 3.5% respectively. The average hardness of samples was 735HV{sub 10}, while the compression strength attained 3810 MPa at the plastic strain of 8.6%. The samples cooled down to 235 °C also showed globular grains surrounded by the eutectic mixture. The TEM studies allowed researchers to identify lower bainite with a plate thickness of about 500 nm (SAEDP from that area showed reflections from α-Fe and Fe{sub 3}C carbides). X-ray diffraction confirmed the presence of 90% ferrite, 6% austenite and 4% carbide. The average hardness of samples annealed at 235 °C decreased to 627HV{sub 10}, while the compression strength decreased to 3100 MPa. The plastic strain increased to 32%. The microstructure of the samples after cooling and

  14. Development of an experimental variable temperature set-up for a temperature range from 2.2 K to 325 K for cost-effective temperature sensor calibration

    Science.gov (United States)

    Pal, Sandip; Kar, Ranjan; Mandal, Anupam; Das, Ananda; Saha, Subrata

    2017-05-01

    A prototype of a variable temperature insert has been developed in-house as a cryogenic thermometer calibration facility. It was commissioned in fulfilment of the very stringent requirements of the temperature control of the cryogenic system. The calibration facility is designed for calibrating industrial cryogenic thermometers that include a temperature sensor and the wires heat-intercept in the 2.2 K-325 K temperature range. The isothermal section of the calibration block onto which the thermometers are mounted is weakly linked with the temperature control zone mounted with cooling capillary coil and cryogenic heater. The connecting wires of the thermometer are thermally anchored with the support of the temperature insert. The calibration procedure begins once the temperature of the support is stabilized. Homogeneity of the calibration block’s temperature is established both by simulation and by cross-comparison of two calibrated sensors. The absolute uncertainty present in temperature measurement is calculated and found comparable with the measured uncertainty at different temperature points. Measured data is presented in comparison to the standard thermometers at fixed points and it is possible to infer that the absolute accuracy achieved is better than  ±0.5% of the reading in comparison to the fixed point temperature. The design and development of simpler, low cost equipment, and approach to analysis of the calibration results are discussed further in this paper, so that it can be easily devised by other researchers.

  15. 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...

  16. Pengaruh Massa Zn Dan Temperatur Hydrotermal Terhadap Struktur Dan Sifat Elektrik Material Graphene

    Directory of Open Access Journals (Sweden)

    Muhammad Rizki Ilhami

    2014-09-01

    Full Text Available Kemajuan teknologi yang sangat berkembang pada saat ini membutuhkan material yang tidak hanya kecil ataupun ringan, tetapi juga memiliki sifat thermal, elektrik, dan mekanik yang baik. Graphene adalah material yang dapat menjawab kebutuhan hal tersebut. Permasalahan yang kemudian muncul adalah proses sintesis massal yang masih menjadi kendala. Penelitian ini bertujuan untuk mensintesis material graphene dengan metode hydrothermal dan menggunakan serbuk Zn sebagai reduktor. Penelitian ini menganalisa pengaruh varaiasi penambahan massa sebesar 0,8 gram, 1,6 gram, dan 2,4 gram zinc serta variasi temperatur hydrthermal 160ᵒC, 180ᵒC, 200ᵒC. Proses karakterisasi material graphene dilakukan dengan pengujian Scanning Electron Microscope (SEM, X-Ray Diffraction (XRD, Fourier Transform Infraredspectroscopy, Thermo Gravimetric Analysis/Differential Scanning Calorimetry (TGA/DSC, dan Four Point Probe digunakan untuk mengetahui nilai konduktivitas elektrik material. Morfologi dari graphene yang dihasilkan berbentuk lembaran-lembaran transparan dan tipis yang saling menumpuk.Semakin banyak serbuk Zn yang diberikan menjadikan permukaan graphene semakin tipis. Nilai konduktivitas elektrik terbesar dihasilkan dari variasi panambahan serbuk zinc sebesar 2,4 gram dan temperatur hydrothermal sebesar 180ᵒC dengan nilai sebesar 0,012526 S/cm.

  17. An accurate energy-range relationship for high-energy electron beams in arbitrary materials

    International Nuclear Information System (INIS)

    Sorcini, B.B.; Brahme, A.

    1994-01-01

    A general analytical energy-range relationship has been derived to relate the practical range, R p to the most probable energy, E p , of incident electron beams in the range 1 to 50 MeV and above, for absorbers of any atomic number. In the present study only Monte Carlo data determined with the new ITS.3 code have been employed. The standard deviations of the mean deviation from the Monte Carlo data at any energy are about 0.10, 0.12, 0.04, 0.11, 0.04, 0.03, 0.02 mm for Be, C, H 2 O, Al, Cu, Ag and U, respectively, and the relative standard deviation of the mean is about 0.5% for all materials. The fitting program gives some priority to water-equivalent materials, which explains the low standard deviation for water. A small error in the fall-off slope can give a different value for R p . We describe a new method which reduces the uncertainty in the R p determination, by fitting an odd function to the descending portion of the depth-dose curve in order to accurately determine the tangent at the inflection point, and thereby the practical range. An approximate inverse relation is given expressing the most probable energy of an electron beam as a function of the practical range. The resultant relative standard error of the energy is less than 0.7%, and the maximum energy error ΔE p is less than 0.3 MeV. (author)

  18. Temperature Range for Metasomatism at the Bakalskoe Siderite Deposits with Use of Geochemical Data

    Directory of Open Access Journals (Sweden)

    M. T. Krupenin

    2017-06-01

    Full Text Available The data obtained with the quantitative microprobe ankerite–siderite composition analysis of seven samples from the different parts of Bakalskoe field showed that the wallrock ankerites in the western and central parts of the ore field differ in average concentrations of FeCO 3 (respectively 14.21 and 20.84 wt.%. However, there is no significant difference in composition of siderites. The calculation of the Mg-Fe metasomatism temperatures based on ankerite-siderite and ankerite-breinerite geothermometers showed the close agreement of the values of both methods at temperatures of 250 °C and above. The average temperatures of siderite metasomatism in the central part of the Bakalskoe ore field are in range 250-270 ° C, and, in the peripheral part, the determined temperature does not exceed 190-220 ° C. These values do not depend on the position of the siderite deposits in stratigraphic level of the Bakalskaya Suite.

  19. Measuring Thermal Conductivity at LH2 Temperatures

    Science.gov (United States)

    Selvidge, Shawn; Watwood, Michael C.

    2004-01-01

    For many years, the National Institute of Standards and Technology (NIST) produced reference materials for materials testing. One such reference material was intended for use with a guarded hot plate apparatus designed to meet the requirements of ASTM C177-97, "Standard Test Method for Steady-State Heat Flux Measurements and Thermal Transmission Properties by Means of the Guarded-Hot-Plate Apparatus." This apparatus can be used to test materials in various gaseous environments from atmospheric pressure to a vacuum. It allows the thermal transmission properties of insulating materials to be measured from just above ambient temperature down to temperatures below liquid hydrogen. However, NIST did not generate data below 77 K temperature for the reference material in question. This paper describes a test method used at NASA's Marshall Space Flight Center (MSFC) to optimize thermal conductivity measurements during the development of thermal protection systems. The test method extends the usability range of this reference material by generating data at temperatures lower than 77 K. Information provided by this test is discussed, as are the capabilities of the MSFC Hydrogen Test Facility, where advanced methods for materials testing are routinely developed and optimized in support of aerospace applications.

  20. Thermal stability of a highly-deformed warm-rolled tungsten plate in the temperature range 1100–1250 °C

    Energy Technology Data Exchange (ETDEWEB)

    Alfonso, A., E-mail: aalz@dtu.dk [Section of Materials and Surface Engineering, Department of Mechanical Engineering, Technical University of Denmark, 2800 Lyngby (Denmark); Sino-Danish Center for Education and Research, Denmark and China (Denmark); Juul Jensen, D. [Danish-Chinese Center for Nanometals, Section of Materials Science and Advanced Characterization, Department of Wind Energy, Technical University of Denmark, Risø Campus, 4000 Roskilde (Denmark); Sino-Danish Center for Education and Research, Denmark and China (Denmark); Luo, G.-N. [Fusion Reactor Materials Science and Technology Division, Institute of Plasma Physics, Chinese Academy of Sciences, 230031 Hefei, Anhui (China); Sino-Danish Center for Education and Research, Denmark and China (Denmark); Pantleon, W. [Section of Materials and Surface Engineering, Department of Mechanical Engineering, Technical University of Denmark, 2800 Lyngby (Denmark); Association EURATOM-DTU (Denmark); Sino-Danish Center for Education and Research, Denmark and China (Denmark)

    2015-10-15

    Highlights: • Annealing kinetics of highly-deformed tungsten up to 190 h between 1100 °C and 1250 °C. • Loss of mechanical strength characterized by Vickers hardness measurements. • Two distinct stages of recovery and recrystallization identified and described by established models. • Activation energy of recrystallization lower than after moderate deformation of tungsten. • Comparable to activation energy of grain boundary diffusion due to abundance of low angle boundaries. - Abstract: Pure tungsten is considered as armor material for the most critical parts of fusion reactors (i.e. the divertor and the first wall), among other reasons due to its high melting point (3422 °C) and recrystallization temperature. The thermal stability of a pure tungsten plate warm-rolled to a high plastic strain by 90% thickness reduction was investigated by isothermal annealing for up to 190 h in the temperature range between 1100 °C and 1250 °C. Vickers hardness testing allowed tracking the changes in mechanical properties caused by recovery and recrystallization. The hardness evolution could be rationalized in terms of a logarithmic recovery kinetics and a Johnson–Mehl–Avrami–Kolmogorov recrystallization kinetics accounting for an incubation time of recrystallization. The observed time spans for recrystallization and the corresponding recrystallization activation energy for this highly deformed plate suggest that large plastic deformations (e.g. applied during shaping) are only suitable to produce tungsten components to be used at relatively low temperatures (up to 900 °C for a 2 years lifespan). Higher operation temperatures will lead to fast degradation of the microstructure during operation.