WorldWideScience

Sample records for single high temperature

  1. Process for Forming a High Temperature Single Crystal Canted Spring

    Science.gov (United States)

    DeMange, Jeffrey J (Inventor); Ritzert, Frank J (Inventor); Nathal, Michael V (Inventor); Dunlap, Patrick H (Inventor); Steinetz, Bruce M (Inventor)

    2017-01-01

    A process for forming a high temperature single crystal canted spring is provided. In one embodiment, the process includes fabricating configurations of a rapid prototype spring to fabricate a sacrificial mold pattern to create a ceramic mold and casting a canted coiled spring to form at least one canted coil spring configuration based on the ceramic mold. The high temperature single crystal canted spring is formed from a nickel-based alloy containing rhenium using the at least one coil spring configuration.

  2. Rapid single flux quantum logic in high temperature superconductor technology

    NARCIS (Netherlands)

    Shunmugavel, K.

    2006-01-01

    A Josephson junction is the basic element of rapid single flux quantum logic (RSFQ) circuits. A high operating speed and low power consumption are the main advantages of RSFQ logic over semiconductor electronic circuits. To realize complex RSFQ circuits in HTS technology one needs a reproducible

  3. Rapid single flux quantum logic in high temperature superconductor technology

    OpenAIRE

    Shunmugavel, K.

    2006-01-01

    A Josephson junction is the basic element of rapid single flux quantum logic (RSFQ) circuits. A high operating speed and low power consumption are the main advantages of RSFQ logic over semiconductor electronic circuits. To realize complex RSFQ circuits in HTS technology one needs a reproducible fabrication of Josephson junctions with low parameter spread. High quality HTS junctions require a fully epitaxial multilayer structure with clean interfaces and a smooth surface morphology. Neodymium...

  4. Defects of diamond single crystal grown under high temperature and high pressure

    Energy Technology Data Exchange (ETDEWEB)

    Su, Qingcai, E-mail: suqc@sdu.edu.cn [Key Laboratory of Liquid Structure and Heredity of Materials (Ministry of Education), Shandong University, Jinan, P. R. China, 250061 (China); School of Materials Science and Engineering, Shandong University, Jinan, P. R. China, 250061 (China); Shandong Engineering Research Center for Superhard Materials, Zoucheng, P. R. China 273500 (China); Zhang, Jianhua [School of Mechanical Engineering, Shandong University, Jinan, P. R. China, 250061 (China); Li, Musen [Key Laboratory of Liquid Structure and Heredity of Materials (Ministry of Education), Shandong University, Jinan, P. R. China, 250061 (China); School of Materials Science and Engineering, Shandong University, Jinan, P. R. China, 250061 (China); Shandong Engineering Research Center for Superhard Materials, Zoucheng, P. R. China 273500 (China)

    2013-11-01

    The diamond single crystal, synthesized with Fe–Ni–C–B system of catalyst under high temperature and high pressure, had been observed by field emission scanning electron microscope and transmission electron microscope. The presence of a cellular structure suggested that the diamond grew from melted catalyst solution and there existed a zone of component supercooling zone in front of the solid–liquid interface. The main impurities in the diamond crystal was (FeNi){sub 23}C{sub 6}. The triangle screw pit revealed on the (111) plane was generated by the screw dislocation meeting the diamond (111) plane at the points of emergence of dislocations. A narrow twin plane was formed between the two (111) plane. - Highlights: • High pressure, high temperature synthesis of diamond single crystal. • Fe–Ni–C–B used as catalyst, graphite as carbon source. • The main impurity in the diamond crystal was (FeNi){sub 23}C{sub 6}. • Surface defects arose from screw dislocations and stacking faults.

  5. Single crystal growth and neutron study of Bi-2212 high temperature superconductor

    International Nuclear Information System (INIS)

    Gu, G.D.; Miles, P.A.; Russell, G. J.; Ivanov, A.; Koshizuka, N.; Kennedy, S.J.

    1999-01-01

    Full text: Many physical properties of the cuprate high temperature superconductors appear to defy the conventional (one-electron) theory of metals. The neutron diffraction and inelastic neutron scattering of the high T c single crystals can provides incisive information about collective magnetic excitations which is required to guide the development of new theories incorporating strong electron correlations. For lack of the suitably large single crystals, inelastic neutron scattering measurements have thus far proven possible for only two of the many families of high temperature superconductors, La 2-x Sr x CuO 4 and YBa 2 Cu 3 O x . While the magnetic pronounced differences that have hampered a unified description of the spin dynamics in the cuprates. In particular, a sharp resonant spin excitation dominates the spectrum in the superconducting state of YBa 2 Cu 3 0 x , but is not found in La 2-x Sr x CuO 4 . We have successfully grown large size Bi-2212 single crystals up to 10*5*1.2 mm 3 by floating zone method, and have studied neutron diffraction and neutron scattering in the single crystals. The Neutron diffraction of the single crystals shows that the crystals are high quality. Here we report the discovery of a magnetic resonance peak in the superconducting state of a third high temperature superconductor of Bi-2212 single crystal by modern neutron optics. The discovery provides evidence of the generality of this unusual phenomenon among the cuprates and greatly extends the empirical basis for its theoretical description. The magnetic resonance peak in Bi-2212 single crystals rules out the possibility or chemical parameters peculiar to YBCO superconductor. Rather, it is an intrinsic feature of the copper oxides whose explanation must be in an integral part of any theory of high temperature superconductivity

  6. Variation of low temperature internal friction of microplastic deformation of high purity molybdenum single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Pal-Val, P.P. (AN Ukrainskoj SSR, Kharkov. Fiziko-Tekhnicheskij Inst. Nizkikh Temperatur); Kaufmann, H.J. (Akademie der Wissenschaften der DDR, Berlin)

    1984-08-01

    Amplitude and temperature spectra of ultrasound absorption in weakly deformed high purity molybdenum single crystals of different orientations were measured. The results were discussed in terms of parameter changes related to quasiparticle or dislocation oscillations, respectively, dislocation point defect interactions as well as defect generation at microplastic deformation.

  7. The growth of single crystals of Ni-W alloy under conditions of high temperature gradient

    International Nuclear Information System (INIS)

    Azhazha, V.M.; Gorbenko, Yu.V.; Kovtun, G.P.; Ladygin, A.N.; Malykhin, D.G.; Rudycheva, T.Yu.; Sverdlov, V.Ya.; Shcherban', A.P.; Zhemanyuk, P.D.; Klochikhin, V.V.

    2004-01-01

    The structure of single crystals of the NV-4 nickel alloy containing 32-36 wt % W is investigated. The temperature gradient at the crystallization front and the velocity of the crystallization front are the variable parameters of directional crystallization. The degrees of structural perfection of the single crystals grown under different conditions are compared. The crystallization parameters providing growth of single crystals that have high structural perfection and can be successfully used as seeds for the growth of single-crystal blades are determined. Typical defects formed upon directional crystallization of single crystals of the Ni-W (35 wt %) alloy are examined. The studied defects are classified, and the factors responsible for the disturbance of the single-crystal structure are analyzed

  8. Mechanisms of High Temperature/Low Stress Creep of Ni-Based Superalloy Single Crystals

    Energy Technology Data Exchange (ETDEWEB)

    Michael J. Mills

    2009-03-05

    Cast nickel-based superalloys are used for blades in land-based, energy conversion and powerplant applications, as well as in aircraft gas turbines operating at temperatures up to 1100 C, where creep is one of the life-limiting factors. Creep of superalloy single crystals has been extensively studied over the last several decades. Surprisingly, only recently has work focused specifically on the dislocation mechanisms that govern high temperature and low stress creep. Nevertheless, the perpetual goal of better engine efficiency demands that the creep mechanisms operative in this regime be fully understood in order to develop alloys and microstructures with improved high temperature capability. At present, the micro-mechanisms controlling creep before and after rafting (the microstructure evolution typical of high temperature creep) has occurred have yet to be identified and modeled, particularly for [001] oriented single crystals. This crystal orientation is most interesting technologically since it exhibits the highest creep strength. The major goal of the program entitled ''Mechanisms of High Temperature/Low Stress Creep of Ni-Based Superalloy Single Crystals'' (DOE Grant DE-FG02-04ER46137) has been to elucidate these creep mechanisms in cast nickel-based superalloys. We have utilized a combination of detailed microstructure and dislocation substructure analysis combined with the development of a novel phase-field model for microstructure evolution.

  9. Performance evaluation of a piezoactuator-based single-stage valve system subjected to high temperature

    International Nuclear Information System (INIS)

    Jeon, Juncheol; Han, Chulhee; Ung Chung, Jye; Choi, Seung-Bok

    2015-01-01

    In this paper, a novel single-stage valve system activated by a piezostack actuator is proposed and experimentally evaluated at both room temperature (20 °C) and high temperature (100 °C) conditions. A hinge-lever displacement amplifier is adopted in the valve system to magnify the displacement generated from the piezostack actuator. After explaining the operating principle of the proposed piezostack-driven single-stage valve system, the geometric dimensions and mechanical properties of the valve components are discussed in details. An experimental apparatus is then manufactured to evaluate the performances of the valve system such as flow rate. The experimental apparatus consists of a heat chamber, which can regulate the temperature of the valve system and oil, pneumatic-hydraulic cylinders, a hydraulic circuit, a pneumatic circuit, electronic devices, an interface card, and a high voltage amplifier. The pneumatic-hydraulic cylinder transforms the pneumatic pressure into hydraulic pressure. The performances of the valve system regarding spool response, pressure drop, and flow rate are evaluated and presented. In addition, the performance of the valve system under high temperature condition is compared with that under room temperature condition. The experimental results are plotted in both frequency and time domains. (paper)

  10. Characterization of biomass combustion at high temperatures based on an upgraded single particle model

    International Nuclear Information System (INIS)

    Li, Jun; Paul, Manosh C.; Younger, Paul L.; Watson, Ian; Hossain, Mamdud; Welch, Stephen

    2015-01-01

    Highlights: • High temperature rapid biomass combustion is studied based on single particle model. • Particle size changes in devolatilization and char oxidation models are addressed. • Time scales of various thermal sub-processes are compared and discussed. • Potential solutions are suggested to achieve better biomass co-firing performances. - Abstract: Biomass co-firing is becoming a promising solution to reduce CO 2 emissions, due to its renewability and carbon neutrality. Biomass normally has high moisture and volatile contents, complicating its combustion behavior, which is significantly different from that of coal. A computational fluid dynamics (CFD) combustion model of a single biomass particle is employed to study high-temperature rapid biomass combustion. The two-competing-rate model and kinetics/diffusion model are used to model biomass devolatilization reaction and char burnout process, respectively, in which the apparent kinetics used for those two models were from high temperatures and high heating rates tests. The particle size changes during the devolatilization and char burnout are also considered. The mass loss properties and temperature profile during the biomass devolatilization and combustion processes are predicted; and the timescales of particle heating up, drying, devolatilization, and char burnout are compared and discussed. Finally, the results shed light on the effects of particle size on the combustion behavior of biomass particle

  11. Specific-heat measurement of single metallic, carbon, and ceramic fibers at very high temperature

    International Nuclear Information System (INIS)

    Pradere, C.; Goyheneche, J.M.; Batsale, J.C.; Dilhaire, S.; Pailler, R.

    2005-01-01

    The main objective of this work is to present a method for measuring the specific heat of single metallic, carbon, and ceramic fibers at very high temperature. The difficulty of the measurement is due to the microscale of the fiber (≅10 μm) and the important range of temperature (700-2700 K). An experimental device, a modelization of the thermal behavior, and an analytic model have been developed. A discussion on the measurement accuracy yields a global uncertainty lower than 10%. The characterization of a tungsten filament with thermal properties identical to those of the bulk allows the validation of the device and the thermal estimation method. Finally, measurements on carbon and ceramic fibers have been done at very high temperature

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

    Science.gov (United States)

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

    2012-07-03

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

  13. A highly crystalline single Au wire network as a high temperature transparent heater.

    Science.gov (United States)

    Rao, K D M; Kulkarni, Giridhar U

    2014-06-07

    A transparent conductor which can generate high temperatures finds important applications in optoelectronics. In this article, a wire network made of Au on quartz is shown to serve as an effective high temperature transparent heater. The heater has been fabricated by depositing Au onto a cracked sacrificial template. The highly interconnected Au wire network thus formed exhibited a transmittance of ∼87% in a wide spectral range with a sheet resistance of 5.4 Ω □(-1). By passing current through the network, it could be joule heated to ∼600 °C within a few seconds. The extraordinary thermal performance and stability owe much to the seamless junctions present in the wire network. Furthermore, the wire network gets self-annealed through joule heating as seen from its increased crystallinity. Interestingly, both transmittance and sheet resistance improved following annealing to 92% and 3.2 Ω □(-1), respectively.

  14. High-quality bulk hybrid perovskite single crystals within minutes by inverse temperature crystallization

    KAUST Repository

    Saidaminov, Makhsud I.

    2015-07-06

    Single crystals of methylammonium lead trihalide perovskites (MAPbX3; MA=CH3NH3+, X=Br− or I−) have shown remarkably low trap density and charge transport properties; however, growth of such high-quality semiconductors is a time-consuming process. Here we present a rapid crystal growth process to obtain MAPbX3 single crystals, an order of magnitude faster than previous reports. The process is based on our observation of the substantial decrease of MAPbX3 solubility, in certain solvents, at elevated temperatures. The crystals can be both size- and shape-controlled by manipulating the different crystallization parameters. Despite the rapidity of the method, the grown crystals exhibit transport properties and trap densities comparable to the highest quality MAPbX3 reported to date. The phenomenon of inverse or retrograde solubility and its correlated inverse temperature crystallization strategy present a major step forward for advancing the field on perovskite crystallization.

  15. Extension of an anisotropic creep model to general high temperature deformation of a single crystal superalloy

    International Nuclear Information System (INIS)

    Pan, L.M.; Ghosh, R.N.; McLean, M.

    1993-01-01

    A physics based model has been developed that accounts for the principal features of anisotropic creep deformation of single crystal superalloys. The present paper extends this model to simulate other types of high temperature deformation under strain controlled test conditions, such as stress relaxation and tension tests at constant strain rate in single crystals subject to axial loading along an arbitrary crystal direction. The approach is applied to the SRR99 single crystal superalloy where a model parameter database is available, determined via analysis of a database of constant stress creep curves. A software package has been generated to simulate the deformation behaviour under complex stress-strain conditions taking into account anisotropic elasticity. (orig.)

  16. Near-infrared refractive index of synthetic single crystal and polycrystalline diamonds at high temperatures

    Science.gov (United States)

    Yurov, V. Yu.; Bushuev, E. V.; Popovich, A. F.; Bolshakov, A. P.; Ashkinazi, E. E.; Ralchenko, V. G.

    2017-12-01

    We measured the refractive index n(T) and thermo-optical coefficient β(T) = (1/n)(dn/dT) of high quality synthetic diamonds from room temperature to high temperatures, up to 1520 K, in near-infrared spectral range at wavelength 1.56 μm, using a low-coherence interferometry. A type IIa single crystal diamond produced by high pressure-high temperature technique and a transparent polycrystalline diamond grown by chemical vapor deposition were tested and revealed a very close n(T) behavior, with n = 2.384 ± 0.001 at T = 300 K, monotonically increasing to 2.428 at 1520 K. The n(T) data corrected to thermal expansion of diamond are well fitted with 3rd order polynomials, and alternatively, with the Bose-Einstein model with an effective oscillator frequency of 970 cm-1. Almost linear n(T) dependence is observed above 800 K. The thermo-optical coefficient is found to increase monotonically from (0.6 ± 0.1) × 10-5 K-1 (300 K) to (2.0 ± 0.1) × 10-5 K-1 (1300 K) with a tendency to saturation at >1200 K. These β(T) values are an order of magnitude lower than those known for Si, GaAs, and InP. The obtained results significantly extend the temperature range, where the refractive index of diamond was previously measured.

  17. Single-Crystal Tungsten Carbide in High-Temperature In-Situ Additive Manufacturing Characterization

    Energy Technology Data Exchange (ETDEWEB)

    Kolopus, James A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Boatner, Lynn A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2017-05-18

    Nanoindenters are commonly used for measuring the mechanical properties of a wide variety of materials with both industrial and scientific applications. Typically, these instruments employ an indenter made of a material of suitable hardness bonded to an appropriate shaft or holder to create an indentation on the material being tested. While a variety of materials may be employed for the indenter, diamond and boron carbide are by far the most common materials used due to their hardness and other desirable properties. However, as the increasing complexity of new materials demands a broader range of testing capabilities, conventional indenter materials exhibit significant performance limitations. Among these are the inability of diamond indenters to perform in-situ measurements at temperatures above 600oC in air due to oxidation of the diamond material and subsequent degradation of the indenters mechanical properties. Similarly, boron carbide also fails at high temperature due to fracture. [1] Transition metal carbides possess a combination of hardness and mechanical properties at high temperatures that offer an attractive alternative to conventional indenter materials. Here we describe the technical aspects for the growth of single-crystal tungsten carbide (WC) for use as a high-temperature indenter material, and we examine a possible approach to brazing these crystals to a suitable mount for grinding and attachment to the indenter instrument. The use of a by-product of the recovery process is also suggested as possibly having commercial value.

  18. Interaction of high cycle fatigue with high temperature creep in superalloy single crystals

    Czech Academy of Sciences Publication Activity Database

    Lukáš, Petr; Kunz, Ludvík; Svoboda, Milan

    2002-01-01

    Roč. 93, č. 7 (2002), s. 661-665 ISSN 0044-3093 R&D Projects: GA AV ČR IAA2041002; GA AV ČR KSK1010104 Institutional research plan: CEZ:AV0Z2041904 Keywords : Single crystals * Creep/fatigue interaction * Persistent slip bands Subject RIV: JL - Materials Fatigue, Friction Mechanics Impact factor: 0.636, year: 2002

  19. Cu-Al-Ni Shape Memory Single Crystal Wires with High Transformation Temperature

    Science.gov (United States)

    Hautcoeur, Alain; Fouché, Florian; Sicre, Jacques

    2016-01-01

    CN-250X is a new material with higher performance than Nickel-Titanium Shape Memory Alloy (SMA). For space mechanisms, the main disadvantage of Nickel-Titanium Shape Memory Alloy is the limited transformation temperature. The new CN-250X Nimesis alloy is a Cu-Al-Ni single crystal wire available in large quantity because of a new industrial process. The triggering of actuators made with this Cu-Al-Ni single crystal wire can range from ambient temperature to 200 C in cycling and even to 250 C in one-shot mode. Another advantage of CN-250X is a better shape recovery (8 to 10%) than Ni-Ti (6 to 7%). Nimesis is the first company able to produce this type of material with its new special industrial process. A characterization study is presented in this work, including the two main solicitation modes for this material: tensile and torsion. Different tests measure the shape recovery of Cu-Al-Ni single crystals wires during heating from room temperature to a temperature higher than temperature of end of martensitic transformation.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-10-15

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

  1. Highly balanced single-layer high-temperature superconductor SQUID gradiometer freely movable within the Earth's magnetic field

    International Nuclear Information System (INIS)

    Schultze, Volkmar; IJsselsteijn, Rob; May, Torsten; Meyer, Hans-Georg

    2003-01-01

    We developed a gradiometer system based on a single-layer high-temperature superconductor dc superconducting quantum interference device (SQUID), which can be freely moved within the Earth's magnetic field during measurement. The problem of circumferential shielding currents in the parallel gradiometer pick-up loop is solved by the use of an appropriately designed magnetometer SQUID integrated on the gradiometer chip. The magnetometer's feedback coil of the flux-locked loop is laid out as a small Helmholtz coil pair, thus keeping the homogeneous magnetic field constant for both the magnetometer and the gradiometer. Therefore, the balance of the directly coupled gradiometer SQUID is enhanced from 100 up to 3800. The noise limited magnetic field gradient resolution of 45 pT m -1 Hz -1/2 is preserved down to frequencies of several Hz even after strong motion in the Earth's magnetic field

  2. Prototyping and performance study of a single crystal diamond detector for operation at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, Amit; Kumar, Arvind; Topkar, Anita, E-mail: anita@barc.gov.in; Das, D.

    2017-06-21

    Prototype single crystal diamond detectors with different types of metallization and post metallization treatment were fabricated for the applications requiring fast neutron measurements in the Indian Test Blanket Module (TBM) at the International Thermonuclear Experimental Reactor (ITER) Experiment. The detectors were characterized by leakage current measurements to ascertain that the leakage currents are low and breakdown voltages are higher than the voltage required for full charge collection. The detector response to charged particles was evaluated using a {sup 238+239} Pu dual energy alpha source. The detectors showed an energy resolution of about 2% at 5.5 MeV. In order to study their suitability for the operation at higher temperatures, leakage current variation and alpha response were studied up to 300 °C. At 300 °C, peaks corresponding to 5.156 MeV and 5.499 MeV alphas could be separated and there was no significant degradation of energy resolution. Finally, the detector response to fast neutrons was evaluated using a Deuterium-Tritium (D-T) neutron generator. The observed spectrum showed peaks corresponding to various channels of n-C interactions with a clear isolated peak corresponding to ~8.5 MeV alphas. The detectors also showed high sensitivity of 3.4×10{sup −2} cps/n/(cm{sup 2} s)–4.5×10{sup −2} cps/n/(cm{sup 2} s) and excellent linearity of response in terms of count rate at different neutron flux in the observed range of 3.2×10{sup 5} n/(cm{sup 2} s) to 2.0×10{sup 6} n/(cm{sup 2} s).

  3. Prototyping and performance study of a single crystal diamond detector for operation at high temperatures

    Science.gov (United States)

    Kumar, Amit; Kumar, Arvind; Topkar, Anita; Das, D.

    2017-06-01

    Prototype single crystal diamond detectors with different types of metallization and post metallization treatment were fabricated for the applications requiring fast neutron measurements in the Indian Test Blanket Module (TBM) at the International Thermonuclear Experimental Reactor (ITER) Experiment. The detectors were characterized by leakage current measurements to ascertain that the leakage currents are low and breakdown voltages are higher than the voltage required for full charge collection. The detector response to charged particles was evaluated using a 238+239 Pu dual energy alpha source. The detectors showed an energy resolution of about 2% at 5.5 MeV. In order to study their suitability for the operation at higher temperatures, leakage current variation and alpha response were studied up to 300 °C. At 300 °C, peaks corresponding to 5.156 MeV and 5.499 MeV alphas could be separated and there was no significant degradation of energy resolution. Finally, the detector response to fast neutrons was evaluated using a Deuterium-Tritium (D-T) neutron generator. The observed spectrum showed peaks corresponding to various channels of n-C interactions with a clear isolated peak corresponding to 8.5 MeV alphas. The detectors also showed high sensitivity of 3.4×10-2 cps/n/(cm2 s)-4.5×10-2 cps/n/(cm2 s) and excellent linearity of response in terms of count rate at different neutron flux in the observed range of 3.2×105 n/(cm2 s) to 2.0×106 n/(cm2 s).

  4. Calcium aluminate silicate Ca2Al2SiO7 single crystal applicable to piezoelectric sensors at high temperature

    Science.gov (United States)

    Takeda, Hiroaki; Hagiwara, Manabu; Noguchi, Hiroaki; Hoshina, Takuya; Takahashi, Tomoko; Kodama, Nobuhiro; Tsurumi, Takaaki

    2013-06-01

    Ca2Al2SiO7 (CAS) bulk single crystals were grown by the Czochralski method. Material constants of the crystal were determined over the driving temperature range of a typical combustion pressure sensor. The electrical resistivity at 800 °C was found to be of the order of 108 Ωcm. We constructed a measurement system for the direct piezoelectric effect at high temperature, and characterized the crystals in a simulated engine cylinder combustion environment. Output charge signal against applied stress was detected at 700 °C. These observations suggest that CAS crystals are superior candidate materials for high temperature for stress sensing.

  5. High-temperature sensor based on an abrupt-taper Michelson interferometer in single-mode fiber.

    Science.gov (United States)

    Xu, Le; Jiang, Lan; Wang, Sumei; Li, Benye; Lu, Yongfeng

    2013-04-01

    This study proposes a high-temperature sensor based on an abrupt fiber-taper Michelson interferometer (FTMI) in single-mode fiber fabricated by a fiber-taper machine and electric-arc discharge. The proposed FTMI is applied to measure temperature and refractive index (RI). A high temperature sensitivity of 118.6 pm/°C is obtained in the temperature range of 500°C-800°C. The wavelength variation is only -0.335 nm for the maximum attenuation peak, with the external RI changed from 1.333 to 1.3902, which is desirable for high-temperature sensing to eliminate the cross sensitivity to RI.

  6. High temperature laser diode based on a single sheet of quantum dots

    Science.gov (United States)

    Ledentsov, N. N.; Shchukin, V. A.; Maximov, M. V.; Shernyakov, Yu M.; Payusov, A. S.; Gordeev, N. Yu; Rouvimov, S. S.

    2015-10-01

    A single sheet of high-density InGaAs quantum dots (QDs) is used as a gain medium of InGaAs-GaAs-AlGaAs lasers. The devices operate at high power in the continuous mode beyond 160 °C with an emission wavelength up to ˜1.27 μm. At short cavity lengths a strong broadening (>300 nm) of the electroluminescence spectrum is observed at high current densities, permitting light sources for broadly wavelength tuneable and multi-wavelength infrared lasers based on a single gain chip, and related frequency conversion devices for the whole visible spectrum range. High power cw operation (>2 W) limited by catastrophic optical mirror damage is realized.

  7. Sensitivity analysis of recovery efficiency in high-temperature aquifer thermal energy storage with single well

    DEFF Research Database (Denmark)

    Jeon, Jun-Seo; Lee, Seung-Rae; Pasquinelli, Lisa

    2015-01-01

    High-temperature aquifer thermal energy storage system usually shows higher performance than other borehole thermal energy storage systems. Although there is a limitation in the widespread use of the HT-ATES system because of several technical problems such as clogging, corrosion, etc., it is get...

  8. Electrical properties of single crystal Yttrium Iron Garnet ultra-thin films at high temperatures

    OpenAIRE

    Thiery, Nicolas; Naletov, Vladimir V.; Vila, Laurent; Marty, Alain; Brenac, Ariel; Jacquot, Jean-François; de Loubens, Grégoire; Viret, Michel; Anane, Abdelmadjid; Cros, Vincent; Youssef, Jamal Ben; Demidov, Vladislav E.; Demokritov, Sergej O.; Klein, Olivier

    2017-01-01

    We report a study on the electrical properties of 19 nm thick Yttrium Iron Garnet (YIG) films grown by liquid phase epitaxy. The electrical conductivity and Hall coefficient are measured in the high temperature range [300,400]~K using a Van der Pauw four-point probe technique. We find that the electrical resistivity decreases exponentially with increasing temperature following an activated behavior corresponding to a band-gap of $E_g\\approx 2$ eV, indicating that epitaxial YIG ultra-thin film...

  9. High-Temperature Superconductivity

    Science.gov (United States)

    Tanaka, Shoji

    2006-12-01

    A general review on high-temperature superconductivity was made. After prehistoric view and the process of discovery were stated, the special features of high-temperature superconductors were explained from the materials side and the physical properties side. The present status on applications of high-temperature superconductors were explained on superconducting tapes, electric power cables, magnets for maglev trains, electric motors, superconducting quantum interference device (SQUID) and single flux quantum (SFQ) devices and circuits.

  10. Single mode step-index polymer optical fiber for humidity insensitive high temperature fiber Bragg grating sensors

    DEFF Research Database (Denmark)

    Woyessa, Getinet; Fasano, Andrea; Stefani, Alessio

    2016-01-01

    We have fabricated the first single-mode step-index and humidity insensitive polymer optical fiber operating in the 850 nm wavelength ranges. The step-index preform is fabricated using injection molding, which is an efficient method for cost effective, flexible and fast preparation of the fiber...... preform. The fabricated single-mode step-index (SI) polymer optical fiber (POF) has a 4.8µm core made from TOPAS grade 5013S-04 with a glass transition temperature of 134°C and a 150 µm cladding made from ZEONEX grade 480R with a glass transition temperature of 138°C. The key advantages of the proposed...... SIPOF are low water absorption, high operating temperature and chemical inertness to acids and bases and many polar solvents as compared to the conventional poly-methyl-methacrylate (PMMA) and polystyrene based POFs. In addition, the fiber Bragg grating writing time is short compared to microstructured...

  11. Single mode step-index polymer optical fiber for humidity insensitive high temperature fiber Bragg grating sensors.

    Science.gov (United States)

    Woyessa, Getinet; Fasano, Andrea; Stefani, Alessio; Markos, Christos; Nielsen, Kristian; Rasmussen, Henrik K; Bang, Ole

    2016-01-25

    We have fabricated the first single-mode step-index and humidity insensitive polymer optical fiber operating in the 850 nm wavelength ranges. The step-index preform is fabricated using injection molding, which is an efficient method for cost effective, flexible and fast preparation of the fiber preform. The fabricated single-mode step-index (SI) polymer optical fiber (POF) has a 4.8µm core made from TOPAS grade 5013S-04 with a glass transition temperature of 134°C and a 150 µm cladding made from ZEONEX grade 480R with a glass transition temperature of 138°C. The key advantages of the proposed SIPOF are low water absorption, high operating temperature and chemical inertness to acids and bases and many polar solvents as compared to the conventional poly-methyl-methacrylate (PMMA) and polystyrene based POFs. In addition, the fiber Bragg grating writing time is short compared to microstructured POFs.

  12. Ferroelectric InMnO{sub 3}: Growth of single crystals, structure and high-temperature phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Bekheet, Maged F., E-mail: maged.bekheet@ceramics.tu-berlin.de [Fachbereich Material‐ und Geowissenschaften, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt (Germany); Fachgebiet Keramische Werkstoffe / Chair of Advanced Ceramic Materials, Institut für Werkstoffwissenschaften und -technologien, Technische Universität Berlin, Hardenbergstraße 40, 10623 Berlin (Germany); Svoboda, Ingrid; Liu, Na [Fachbereich Material‐ und Geowissenschaften, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt (Germany); Bayarjargal, Lkhamsuren [Institut für Geowissenschaften, Goethe-Universität, Altenhöferallee 1, d-60438 Frankfurt a.M. (Germany); Irran, Elisabeth [Institut für Chemie, Technische Universität Berlin, Straße des 17, Juni 135, 10623 Berlin (Germany); Dietz, Christian; Stark, Robert W.; Riedel, Ralf [Fachbereich Material‐ und Geowissenschaften, Technische Universität Darmstadt, Alarich-Weiss-Straße 2, 64287 Darmstadt (Germany); Gurlo, Aleksander [Fachgebiet Keramische Werkstoffe / Chair of Advanced Ceramic Materials, Institut für Werkstoffwissenschaften und -technologien, Technische Universität Berlin, Hardenbergstraße 40, 10623 Berlin (Germany)

    2016-09-15

    To understand the origin of the ferroelectricity in InMnO{sub 3}, single crystals with average size of 1 mm were grown in PbF{sub 2} flux at 950 °C. The results of single crystal X-ray diffraction, second harmonic generation and piezoresponse force microscopy studies of high-quality InMnO{sub 3} single crystals reveal that the room-temperature state in this material is ferroelectric with P6{sub 3}cm symmetry. The polar InMnO{sub 3} specimen undergoes a reversible phase transition from non-centrosymmetric P6{sub 3}cm structure to a centrosymmetric P6{sub 3}/mmc structure at 700 °C as confirmed by the in situ high-temperature Raman spectroscopic and synchrotron X-ray diffraction experiments. - Graphical abstract: Piezoresponse fore microscopy (PFM) studies of high quality InMnO{sub 3} single crystal revealed that the room-temperature state of this material is ferroelectric with a clear cloverleaf pattern corresponding to six antiphase ferroelectric domains with alternating polarization ±P{sub z}. Display Omitted - Highlights: • InMnO{sub 3} single crystals with average size of 1 mm were grown in PbF{sub 2} flux at 950 °C. • The room-temperature state of InMnO{sub 3} is ferroelectric with polar P6{sub 3}cm structure. • PolarInMnO{sub 3} reversibly transforms to a centrosymmetric P6{sub 3}/mmc structure above 700 °C.

  13. Creation of Single Chain of Nanoscale Skyrmion Bubbles with Record-high Temperature Stability in a Geometrically Confined Nanostripe

    KAUST Repository

    Hou, Zhipeng

    2018-01-04

    Nanoscale topologically nontrivial spin textures, such as magnetic skyrmions, have been identified as promising candidates for the transport and storage of information for spintronic applications, notably magnetic racetrack memory devices. The design and realization of a single skyrmion chain at room temperature (RT) and above in the low-dimensional nanostructures are of great importance for future practical applications. Here, we report the creation of a single skyrmion bubble chain in a geometrically confined Fe3Sn2 nanostripe with a width comparable to the featured size of a skyrmion bubble. Systematic investigations on the thermal stability have revealed that the single chain of skyrmion bubbles can keep stable at temperatures varying from RT up to a record-high temperature of 630 K. This extreme stability can be ascribed to the weak temperature-dependent magnetic anisotropy and the formation of edge states at the boundaries of the nanostripes. The realization of the highly stable skyrmion bubble chain in a geometrically confined nanostructure is a very important step toward the application of skyrmion-based spintronic devices.

  14. Temperature dependence of Ce:YAG single-crystal phosphors for high-brightness white LEDs/LDs

    Science.gov (United States)

    Arjoca, Stelian; Víllora, Encarnación G.; Inomata, Daisuke; Aoki, Kazuo; Sugahara, Yoshiyuki; Shimamura, Kiyoshi

    2015-05-01

    The growth of Ce:Y3Al5O12(Ce:YAG) single-crystal phosphors (SCPs) by the Czochralski technique is analyzed in terms of segregation coefficient, solubility and absorption cross-section. The emission characteristics of these SCPs are investigated in a wide temperature range, from liquid He temperature up to 500 °C. The internal quantum efficiency of SCPs achieves its maximum at about 250 °C. Thermal quenching of SCPs at high temperature is attributed to the Mott-Seitz mechanism. In the case of ceramic powder phosphors, a continuous droop is observed with the temperature due to defect-related non-radiative recombination paths. It is shown that (Ce:YAG SCPs + blue LEDs/LDs) can cover a wide range of color temperatures 5500-7000 K, with color rendering indices around 70. In conclusion, it is shown that Ce:YAG SCPs are the most efficient and temperature stable converters to fabricate high-brightness white light sources with high-power blue LEDs and LDs.

  15. NaCaCo2F7: A single-crystal high-temperature pyrochlore antiferromagnet

    Science.gov (United States)

    Krizan, J. W.; Cava, R. J.

    2014-06-01

    We report the magnetic characterization of the frustrated transition metal pyrochlore NaCaCo2F7. This material has high spin Co2+ in CoF6 octahedra in a pyrochlore lattice and disordered nonmagnetic Na and Ca on the large-atom sites in the structure. Large crystals grown by the floating zone method were studied. The magnetic susceptibility is isotropic; the Co moment is larger than the spin-only value; and in spite of the large Curie Weiss theta (-140 K), freezing of the spin system, as characterized by peaks in the ac and dc susceptibility and specific heat, does not occur until around 2.4 K. This yields a frustration index of f=-θCW/Tf≈56, an indication that the system is highly frustrated. The observed entropy loss at the freezing transition is low, indicating that magnetic entropy remains present in the system at 0.6 K. The compound may be the realization of a frustrated pyrochlore antiferromagnet with weak bond disorder. The high magnetic interaction strength, strong frustration, and the availability of large single crystals makes NaCaCo2F7 an interesting alternative to rare earth oxide pyrochlores for the study of geometric magnetic frustration in pyrochlore lattices.

  16. Contribution of a solute atoms in the relaxation phenomenon at high temperature in Cu-Al single crystal alloys

    Science.gov (United States)

    Belamri, C.; Belhas, S.; Rivière, A.

    2009-11-01

    Two Cu-Al single crystals with 7 and 14 at. % Al respectively have been studied using isothermal mechanical spectroscopy (IMS) technique. After a 1% cold work by torsion, the samples have been progressively heated to 1140 K and then cooled until room temperature. IMS experiments allow to compare the isothermal internal friction spectra obtained during the heating (in this case, the annealing temperature is equal to the temperature of measurement) with the measurements performed at various temperature during the cooling after the annealing at 1140 K. Three relaxation peaks were observed. The first one at about 0.4 TM (TM: melting point) is a Zener relaxation peak (PZ) due to the reorientation under constraint of pairs of aluminium atoms. The high temperature annealing does not influence PZ. At about 0.6TM, a peak (P1) related to a dislocation mechanism is evidenced. The relaxation strength of P1 peak decreases with the temperature and a new relaxation peak (P2) is progressively developed. The IMS spectra obtained during the cooling evidenced only P2. The relaxation parameters obtained by the Arrhenius plots and the evolution with the annealing temperature allow to assign P1 and P2 to an interaction between the dislocations and the solute atoms according to the Darinskiy model.

  17. Development of a new micro-furnace for "in situ" high-temperature single crystal X-ray diffraction measurements

    Science.gov (United States)

    Alvaro, Matteo; Angel, Ross J.; Marciano, Claudio; Zaffiro, Gabriele; Scandolo, Lorenzo; Mazzucchelli, Mattia L.; Milani, Sula; Rustioni, Greta; Domeneghetti, Chiara M.; Nestola, Fabrizio

    2015-04-01

    Several experimental methods to reliably determine elastic properties of minerals at non-ambient conditions have been developed. In particular, different techniques for generating high-pressure and high-temperature have been successfully adopted for single-crystal and powder X-ray diffraction measurements. High temperature devices for "in-situ" measurements should provide the most controlled isothermal environment as possible across the entire sample. It is intuitive that in general, thermal gradients across the sample increase as the temperature increases. Even if the small isothermal volume required for single-crystal X-ray diffraction experiments makes such phenomena almost negligible, the design of a furnace should also aim to reduce thermal gradients by including a large thermal mass that encloses the sample. However this solution often leads to complex design that results in a restricted access to reciprocal space or attenuation of the incident or diffracted intensity (with consequent reduction of the accuracy and/or precision in lattice parameter determination). Here we present a newly-developed H-shaped Pt-Pt/Rh resistance microfurnace for in-situ high-temperature single-crystal X-ray diffraction measurements. The compact design of the furnace together with the long collimator-sample-detector distance allows us to perform measurements up to 2θ = 70° with no further restrictions on any other angular movement. The microfurnace is equipped with a water cooling system that allows a constant thermal gradient to be maintained that in turn guarantees thermal stability with oscillations smaller than 5°C in the whole range of operating T of room-T to 1200°C. The furnace has been built for use with a conventional 4-circle Eulerian geometry equipped with point detector and automated with the SINGLE software (Angel and Finger 2011) that allows the effects of crystal offsets and diffractometer aberrations to be eliminated from the refined peak positions by the 8

  18. Determination of γ/ γ' Lattice Misfit in Ni-Based Single-Crystal Superalloys at High Temperatures by Neutron Diffraction

    Science.gov (United States)

    Huang, Shenyan; An, Ke; Gao, Yan; Suzuki, Akane

    2018-03-01

    Constrained γ/ γ' lattice misfit as a function of temperature (room temperature, 871 °C, 982 °C, 1093 °C, and 1204 °C) is measured by neutron diffraction on the first-generation Ni-based single-crystal superalloy René N4 and second-generation superalloys René N5, CMSX4, and PWA1484. All the alloys studied show negative misfit at temperatures above 871 °C. For René N4, René N5, and PWA1484, the misfit becomes less negative at temperatures above 1093 °C, possibly due to either the chemistry effect or internal stress relaxation. The magnitude of the misfit shows a qualitative agreement with Caron's misfit model based on Vegard's coefficients. The Re-free alloy René N4 was found to have a larger γ lattice parameter and γ/ γ' misfit due to higher fractions of Cr, Ti, and Mo. After 100 hours of annealing at high temperatures, René N5 shows a more negative misfit than the misfit after the standard heat treatment.

  19. High-temperature and low-stress creep anisotropy of single-crystal superalloys

    Czech Academy of Sciences Publication Activity Database

    Jacome, L. A.; Nortershauser, P.; Heyer, J. K.; Lahni, A.; Frenzel, J.; Dlouhý, Antonín; Somsen, C.; Eggeler, G.

    2013-01-01

    Roč. 61, č. 8 (2013), s. 2926-2943 ISSN 1359-6454 R&D Projects: GA ČR(CZ) GA202/09/2073 Institutional support: RVO:68081723 Keywords : superalloy single crystals * creep anisotropy * rafting * dislocations * deformation mechanisms Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 3.940, year: 2013

  20. A model for high temperature creep of single crystal superalloys based on nonlocal damage and viscoplastic material behavior

    Science.gov (United States)

    Trinh, B. T.; Hackl, K.

    2014-07-01

    A model for high temperature creep of single crystal superalloys is developed, which includes constitutive laws for nonlocal damage and viscoplasticity. It is based on a variational formulation, employing potentials for free energy, and dissipation originating from plasticity and damage. Evolution equations for plastic strain and damage variables are derived from the well-established minimum principle for the dissipation potential. The model is capable of describing the different stages of creep in a unified way. Plastic deformation in superalloys incorporates the evolution of dislocation densities of the different phases present. It results in a time dependence of the creep rate in primary and secondary creep. Tertiary creep is taken into account by introducing local and nonlocal damage. Herein, the nonlocal one is included in order to model strain localization as well as to remove mesh dependence of finite element calculations. Numerical results and comparisons with experimental data of the single crystal superalloy LEK94 are shown.

  1. Materials process and applications of single grain (RE)-Ba-Cu-O bulk high-temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Li Beizhan; Zhou Difan; Xu Kun; Hara, Shogo; Tsuzuki, Keita; Miki, Motohiro; Felder, Brice; Deng Zigang [Laboratory of Applied Physics, Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology (TUMSAT), 2-1-6, Etchu-jima, Koto-ku, Tokyo 135-8533 (Japan); Izumi, Mitsuru, E-mail: izumi@kaiyodai.ac.jp [Laboratory of Applied Physics, Department of Marine Electronics and Mechanical Engineering, Tokyo University of Marine Science and Technology (TUMSAT), 2-1-6, Etchu-jima, Koto-ku, Tokyo 135-8533 (Japan)

    2012-11-20

    This paper reviews recent advances in the melt process of (RE)-Ba-Cu-O [(RE)BCO, where RE represents a rare earth element] single grain high-temperature superconductors (HTSs), bulks and its applications. The efforts on the improvement of the magnetic flux pinning with employing the top-seeded melt-growth process technique and using a seeded infiltration and growth process are discussed. Which including various chemical doping strategies and controlled pushing effect based on the peritectic reaction of (RE)BCO. The typical experiment results, such as the largest single domain bulk, the clear TEM observations and the significant critical current density, are summarized together with the magnetization techniques. Finally, we highlight the recent prominent progress of HTS bulk applications, including Maglev, flywheel, power device, magnetic drug delivery system and magnetic resonance devices.

  2. Materials process and applications of single grain (RE)-Ba-Cu-O bulk high-temperature superconductors

    Science.gov (United States)

    Li, Beizhan; Zhou, Difan; Xu, Kun; Hara, Shogo; Tsuzuki, Keita; Miki, Motohiro; Felder, Brice; Deng, Zigang; Izumi, Mitsuru

    2012-11-01

    This paper reviews recent advances in the melt process of (RE)-Ba-Cu-O [(RE)BCO, where RE represents a rare earth element] single grain high-temperature superconductors (HTSs), bulks and its applications. The efforts on the improvement of the magnetic flux pinning with employing the top-seeded melt-growth process technique and using a seeded infiltration and growth process are discussed. Which including various chemical doping strategies and controlled pushing effect based on the peritectic reaction of (RE)BCO. The typical experiment results, such as the largest single domain bulk, the clear TEM observations and the significant critical current density, are summarized together with the magnetization techniques. Finally, we highlight the recent prominent progress of HTS bulk applications, including Maglev, flywheel, power device, magnetic drug delivery system and magnetic resonance devices.

  3. Single Nanoparticle Mass Spectrometry as a High Temperature Kinetics Tool: Sublimation, Oxidation, and Emission Spectra of Hot Carbon Nanoparticles.

    Science.gov (United States)

    Howder, Collin R; Long, Bryan A; Gerlich, Dieter; Alley, Rex N; Anderson, Scott L

    2015-12-17

    In single nanoparticle mass spectrometry, individual charged nanoparticles (NPs) are trapped in a quadrupole ion trap and detected optically, allowing their mass, charge, and optical properties to be monitored continuously. Previous experiments of this type probed NPs that were either fluorescent or large enough to detect by light scattering. Alternatively, small NPs can be heated to temperatures where thermally excited emission is strong enough to allow detection, and this approach should provide a new tool for measurements of sublimation and surface reaction kinetics of materials at high temperatures. As an initial test, we report a study of carbon NPs in the 20-50 nm range, heated by 10.6 μm, 532 nm, or 445 nm lasers. The kinetics for sublimation and oxidation of individual carbon NPs were studied, and a model is presented for the factors that control the NP temperature, including laser heating, and cooling by sublimation, buffer gas collisions, and radiation. The estimated NP temperatures were in the 1700-2000 K range, and the NP absorption cross sections ranged from ∼0.8 to 0.2% of the geometric cross sections for 532 nm and 10.6 μm excitation, respectively. Emission spectra of single NPs and small NP ensembles show a feature in the IR that appears to be the high energy tail of the thermal (blackbody-like) emission expected from hot particles but also a discrete feature peaking around 750 nm. Both the IR tail and 750 nm peak are observed for all particles and for both IR and visible laser excitation. No significant difference was observed between graphite and amorphous carbon NPs.

  4. Crystal growth and anisotropy of high temperature thermoelectric properties of yttrium borosilicide single crystals

    Energy Technology Data Exchange (ETDEWEB)

    Hossain, M. Anwar [International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba 305-0044 (Japan); Center for Crystal Science and Technology, University of Yamanashi, Miyamae 7-32, Kofu, Yamanashi 400-8511 (Japan); Tanaka, Isao [Center for Crystal Science and Technology, University of Yamanashi, Miyamae 7-32, Kofu, Yamanashi 400-8511 (Japan); Tanaka, Takaho; Khan, A. Ullah [International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba 305-0044 (Japan); Mori, Takao, E-mail: MORI.Takao@nims.go.jp [International Center for Materials Nanoarchitectonics (WPI-MANA), National Institute for Materials Science (NIMS), Namiki 1-1, Tsukuba 305-0044 (Japan); Graduate School of Pure and Applied Sciences, University of Tsukuba, 1-1-1 Tennoudai, Tsukuba 305-8671 (Japan)

    2016-01-15

    We studied thermoelectric properties of YB{sub 41}Si{sub 1.3} single crystals grown by the floating zone method. The composition of the grown crystal was confirmed by electron probe micro-analysis. We have determined the growth direction for the first time for these borosilicides, and discovered relatively large anisotropy in electrical properties. We measured the electrical resistivity and Seebeck coefficient along [510] (the growth direction) and [052] directions and we found that this crystal exhibits strong electrical anisotropy with a maximum of more than 8 times. An interesting layered structural feature is revealed along [510] with dense boron cluster layers and yttrium layers, with conductivity enhanced along this direction. We obtained 3.6 times higher power factor along [510] compared to that along [052]. Although the ZT of the present system is low, anisotropy in the thermoelectric properties of a boride was reported for the first time, and can be a clue in developing other boride systems also. - Graphical abstract: The growth direction ([510]) was determined for the first time in YB{sub 41}Si{sub 1.3} single crystals and revealed an interesting layered feature of boron clusters and metal atoms, along which the electrical conductivity and thermoelectric power factor was strongly enhanced. - Highlights: • We have grown YB{sub 41}Si{sub 1.3} single crystals by the floating zone method. • Growth direction of [510] determined for first time in REB{sub 41}Si{sub 1.2}. • Electrical resistivity was strongly anisotropic with possible enhancement along metal layers. • The obtained power factor along [510] is 3.6 times higher than that along [052].

  5. Room-temperature ferromagnetism with high magnetic moment in Cu-doped AlN single crystal whiskers

    Science.gov (United States)

    Jiang, Liang-Bao; Liu, Yu; Zuo, Si-Bin; Wang, Wen-Jun

    2015-02-01

    Ferromagnetism is investigated in high-quality Cu-doped AlN single crystal whiskers. The whiskers exhibit room-temperature ferromagnetism with a magnetic moment close to the results from first-principles calculations. High crystallinity and low Cu concentrations are found to be indispensable for high magnetic moments. The difference between the experimental and theoretical moment values is explored in terms of the influence of nitrogen vacancies. The calculated results demonstrate that nitrogen vacancies can reduce the magnetic moments of Cu atom. Project supported by the National Basic Research Program of China (Grant No. 2013CB932901), the National Natural Science Foundation of China (Grant Nos. 51372267, 51210105026, and 51172270), the Funds from the Chinese Academy of Sciences, the International Centre for Diffraction Data, USA (2013 Ludo Frevel Crystallography Scholarship Award), and the Funds from the Ministry of Education of China (2012 Academic Scholarship Award for Doctoral Candidates).

  6. A compact single-camera system for high-speed, simultaneous 3-D velocity and temperature measurements.

    Energy Technology Data Exchange (ETDEWEB)

    Lu, Louise; Sick, Volker; Frank, Jonathan H.

    2013-09-01

    The University of Michigan and Sandia National Laboratories collaborated on the initial development of a compact single-camera approach for simultaneously measuring 3-D gasphase velocity and temperature fields at high frame rates. A compact diagnostic tool is desired to enable investigations of flows with limited optical access, such as near-wall flows in an internal combustion engine. These in-cylinder flows play a crucial role in improving engine performance. Thermographic phosphors were proposed as flow and temperature tracers to extend the capabilities of a novel, compact 3D velocimetry diagnostic to include high-speed thermometry. Ratiometric measurements were performed using two spectral bands of laser-induced phosphorescence emission from BaMg2Al10O17:Eu (BAM) phosphors in a heated air flow to determine the optimal optical configuration for accurate temperature measurements. The originally planned multi-year research project ended prematurely after the first year due to the Sandia-sponsored student leaving the research group at the University of Michigan.

  7. Single and Networked ZnO-CNT Hybrid Tetrapods for Selective Room-Temperature High-Performance Ammonia Sensors.

    Science.gov (United States)

    Schütt, Fabian; Postica, Vasile; Adelung, Rainer; Lupan, Oleg

    2017-07-12

    Highly porous hybrid materials with unique high-performance properties have attracted great interest from the scientific community, especially in the field of gas-sensing applications. In this work, tetrapodal-ZnO (ZnO-T) networks were functionalized with carbon nanotubes (CNTs) to form a highly efficient hybrid sensing material (ZnO-T-CNT) for ultrasensitive, selective, and rapid detection of ammonia (NH 3 ) vapor at room temperature. By functionalizing the ZnO-T networks with 2.0 wt % of CNTs by a simple dripping procedure, an increase of 1 order of magnitude in response (from about 37 to 330) was obtained. Additionally, the response and recovery times were improved (by decreasing them from 58 and 61 s to 18 and 35 s, respectively). The calculated lowest detection limit of 200 ppb shows the excellent potential of the ZnO-T-CNT networks as NH 3 vapor sensors. Room temperature operation of such networked ZnO-CNT hybrid tetrapods shows an excellent long-time stability of the fabricated sensors. Additionally, the gas-sensing mechanism was identified and elaborated based on the high porosity of the used three-dimensional networks and the excellent conductivity of the CNTs. On top of that, several single hybrid microtetrapod-based devices were fabricated (from samples with 2.0 wt % CNTs) with the help of the local metal deposition function of a focused ion beam/scanning electron microscopy instrument. The single microdevices are based on tetrapods with arms having a diameter of around 0.35 μm and show excellent NH 3 sensing performance with a gas response (I gas /I air ) of 6.4. Thus, the fabricated functional networked ZnO-CNT hybrid tetrapods will allow to detect ammonia and to quantify its concentration in automotive, environmental monitoring, chemical industry, and medical diagnostics.

  8. High temperature structural silicides

    International Nuclear Information System (INIS)

    Petrovic, J.J.

    1997-01-01

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

  9. High resolution in-situ x-ray diffraction of single carbon fibres at high loads and temperatures up to 1800oC

    International Nuclear Information System (INIS)

    Rennhofer, H.; Puchegger, S.; Pabisch, S.; Weinberger, M.; Peterlik, H.; Loidl, D.; Paris, O.

    2008-01-01

    Full text: A specially designed test equipment has been developed to perform in-situ x-ray diffraction experiments of single carbon fibres (HTA 5131, diameter 7 microns) with simultaneously applying high loads and temperatures up to 1800 o C. The test equipment operates in vacuum (pressure -4 mbar) and direct heating with cold grips is used. The structural change of the nm-wide crystallites, in particular with respect to their size, orientation and lattice parameters is followed in dependence on load and temperature. The results are compared to similar experiments on fiber-bundles, which were performed in the laboratory equipment. (author)

  10. Molecular-dynamic simulations of the thermophysical properties of hexanitrohexaazaisowurtzitane single crystal at high pressures and temperatures

    Science.gov (United States)

    Kozlova, S. A.; Gubin, S. A.; Maklashova, I. V.; Selezenev, A. A.

    2017-11-01

    Molecular dynamic simulations of isothermal compression parameters are performed for a hexanitrohexaazaisowurtzitane single crystal (C6H6O12N12) using a modified ReaxFF-log reactive force field. It is shown that the pressure-compression ratio curve for a single C6H6O12N12 crystal at constant temperature T = 300 K in pressure range P = 0.05-40 GPa is in satisfactory agreement with experimental compression isotherms obtained for a single C6H6O12N12 crystal. Hugoniot molecular-dynamic simulations of the shock-wave hydrostatic compression of a single C6H6O12N12 crystal are performed. Along with Hugoniot temperature-pressure curves, calculated shock-wave pressure-compression ratios for a single C6H6O12N12 crystal are obtained for a wide pressure range of P = 1-40 GPa. It is established that the percussive adiabat obtained for a single C6H6O12N12 crystal is in a good agreement with the experimental data. All calculations are performed using a LAMMPS molecular dynamics simulation software package that provides a ReaxFF-lg reactive force field to support the approach.

  11. High Temperature Deformation Mechanism in Hierarchical and Single Precipitate Strengthened Ferritic Alloys by In Situ Neutron Diffraction Studies

    Science.gov (United States)

    Song, Gian; Sun, Zhiqian; Li, Lin; Clausen, Bjørn; Zhang, Shu Yan; Gao, Yanfei; Liaw, Peter K.

    2017-04-01

    The ferritic Fe-Cr-Ni-Al-Ti alloys strengthened by hierarchical-Ni2TiAl/NiAl or single-Ni2TiAl precipitates have been developed and received great attentions due to their superior creep resistance, as compared to conventional ferritic steels. Although the significant improvement of the creep resistance is achieved in the hierarchical-precipitate-strengthened ferritic alloy, the in-depth understanding of its high-temperature deformation mechanisms is essential to further optimize the microstructure and mechanical properties, and advance the development of the creep resistant materials. In the present study, in-situ neutron diffraction has been used to investigate the evolution of elastic strain of constitutive phases and their interactions, such as load-transfer/load-relaxation behavior between the precipitate and matrix, during tensile deformation and stress relaxation at 973 K, which provide the key features in understanding the governing deformation mechanisms. Crystal-plasticity finite-element simulations were employed to qualitatively compare the experimental evolution of the elastic strain during tensile deformation at 973 K. It was found that the coherent elastic strain field in the matrix, created by the lattice misfit between the matrix and precipitate phases for the hierarchical-precipitate-strengthened ferritic alloy, is effective in reducing the diffusional relaxation along the interface between the precipitate and matrix phases, which leads to the strong load-transfer capability from the matrix to precipitate.

  12. Single mode step-index polymer optical fiber for humidity insensitive high temperature fiber Bragg grating sensors

    OpenAIRE

    Woyessa, Getinet; Fasano, Andrea; Stefani, Alessio; Markos, Christos; Nielsen, Kristian; Rasmussen, Henrik K.; Bang, Ole

    2016-01-01

    We have fabricated the first single-mode step-index and humidity insensitive polymer optical fiber operating in the 850 nm wavelength ranges. The step-index preform is fabricated using injection molding, which is an efficient method for cost effective, flexible and fast preparation of the fiber preform. The fabricated single-mode step-index (SI) polymer optical fiber (POF) has a 4.8µm core made from TOPAS grade 5013S-04 with a glass transition temperature of 134°C and a 150 µm cladding made f...

  13. Growth and Characterization of Ca2Al2SiO7 Piezoelectric Single Crystals for High-Temperature Sensor Applications

    Science.gov (United States)

    Hagiwara, Manabu; Noguchi, Hiroaki; Hoshina, Takuya; Takeda, Hiroaki; Fujihara, Shinobu; Kodama, Nobuhiro; Tsurumi, Takaaki

    2013-09-01

    The electrical properties of a piezoelectric single crystal of calcium aluminate silicate Ca2Al2SiO7 (CAS) were studied at elevated temperatures and its applicability to high-temperature pressure sensors was investigated. The CAS bulk single crystal was grown by the Czochralski method. The piezoelectric d14 and d36 constants were respectively evaluated as 6.04 and 4.04 pC/N by the resonance and antiresonance method. The temperature dependence of the piezoelectric constant was investigated at temperatures up to 500 °C. The electrical resistivity at 800 °C was on the order of 108 Ω.cm along both the crystallographic a- and c-axes. The measurement of direct piezoelectric response at 700 °C demonstrated that the CAS crystal could detect a pseudo-combustion pressure change of an automobile engine. Our observations suggest that CAS crystals are superior candidates for sensing pressure at high temperatures.

  14. Inclusions related to catalyst and medium for transmitting pressure in diamond single crystals grown at high temperature and high pressure from the Fe-C system

    International Nuclear Information System (INIS)

    Yin Longwei; Li Musen; Hao Zhaoyin; Zhang Jiongfa

    2001-01-01

    Inclusion entrapment in a crystal is one of the most important characteristics for the crystal growth technique from solution. Diamond single crystals grown from the Fe-C system at high temperature-high pressure usually contain inclusions related to the molten catalyst and the medium (pyrophyllite) for transmitting pressure. During the growth of the diamond, the inclusions are trapped by the growth front or are formed through reaction between the contaminants trapped in the diamond. In the present article, the inclusions related to the catalyst and pyrophyllite were systemically examined by transmission electron microscopy. The chemical composition and crystal structure of the inclusions were, for the first time, determined by selected area electron diffraction pattern combined with energy dispersive x-ray spectrometry. It was shown that the inclusions are mainly composed of orthorhombic Fe 3 C, orthorhombic FeSi 2 , hexagonal SiO 2 and face-centred cubic SiC. (author)

  15. Precipitation in solid solution and structural transformations in single crystals of high rhenium ruthenium-containing nickel superalloys at high-temperature creep

    Energy Technology Data Exchange (ETDEWEB)

    Alekseev, A.A.; Petrushin, N.V.; Zaitsev, D.V.; Treninkov, I.A.; Filonova, E.V. [All-Russian Scientific Research Institute of Aviation Materials (VIAM), Moscow (Russian Federation)

    2010-07-01

    The phase composition and structure of single crystals of two superalloys (alloy 1 and alloy 2) were investigated in this work. For alloy 1 (Re - 9 wt%) the kinetics of precipitation in solid solution at heat treatment (HT) was investigated. TEM and X-Ray examinations have revealed that during HT rhombic phase (R-phase) precipitation (Immm class (BCR)) occurs. The TTT diagram is plotted, it contains the time-temperature area of the existence of R-phase particles. The element content of R-phase is identified (at. %): Re- 51.5; Co- 23.5; Cr- 14.8; Mo- 4.2; W- 3.3; Ta- 2.7. For alloy 2 (Re - 6.5 wt %, Ru - 4 wt %) structural transformations at high-temperature creep are investigated. By dark-field TEM methods it is established, that in alloy 2 the additional phase with a rhombic lattice is formed during creep. Particles of this phase precipitate in {gamma}-phase and their quantity increases during high-temperature creep. It is revealed that during creep 3-D dislocation network is formed in {gamma}-phase. At the third stage of creep the process of inversion structure formation is observed in the alloy, i.e. {gamma}'-phase becomes a matrix. Thus during modeling creep the volume fraction of {gamma}'-phase in the samples increases from 30% (at creep duration of 200 hrs) up to 55% (at 500 hrs). The processes of structure formation in Re and Ru-containing nickel superalloys are strongly affected by decomposition of solid solution during high-temperature creep that includes precipitation of additional TCP-phases. (orig.)

  16. Renormalized phonon frequencies and electric resistivity along the c-axis in single-plane high-temperature superconductors: A double-well analysis

    CERN Document Server

    Georgiev, M; Polyanski, I; Petrova, P T; Tsintsarska, S; Gochev, A

    2001-01-01

    We consider the dynamic interlayer charge transfer across apex oxygens between CuO sub 2 planes in single-layered high-T sub c superconductors. Phonon-coupled axial transfer rates are derived by means of the reaction-rate method. They lead straightforwardly to temperature dependences for the axial resistivity. Doping and temperature dependences are also derived for the renormalized frequencies of phonon modes coupled to the interlayer charge transfer. Our results are compared with experimentally observed dependences. (author)

  17. High-Temperature Piezoelectric Sensing

    Science.gov (United States)

    Jiang, Xiaoning; Kim, Kyungrim; Zhang, Shujun; Johnson, Joseph; Salazar, Giovanni

    2014-01-01

    Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discussed. Secondly, recent work on high-temperature piezoelectric sensors including accelerometer, surface acoustic wave sensor, ultrasound transducer, acoustic emission sensor, gas sensor, and pressure sensor for temperatures up to 1,250 °C were reviewed. Finally, discussions of existing challenges and future work for high-temperature piezoelectric sensing are presented. PMID:24361928

  18. High-Temperature Piezoelectric Sensing

    Directory of Open Access Journals (Sweden)

    Xiaoning Jiang

    2013-12-01

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

  19. High temperature sensor

    Science.gov (United States)

    Tokarz, Richard D.

    1982-01-01

    A high temperature sensor includes a pair of electrical conductors separated by a mass of electrical insulating material. The insulating material has a measurable resistivity within the sensor that changes in relation to the temperature of the insulating material within a high temperature range (1,000 to 2,000 K.). When required, the sensor can be encased within a ceramic protective coating.

  20. Observations of Glide and Decomposition of a Dislocations at High Temperatures in Ni-Al Single Crystals Deformed along the Hard Orientation

    Science.gov (United States)

    Srinivasan, R.; Daw, M. S.; Noebe, R. D.; Mills, M. J.

    2003-01-01

    Ni-44at.% Al and Ni-50at.% single crystals were tested in compression in the hard (001) orientations. The dislocation processes and deformation behavior were studied as a function of temperature, strain and strain rate. A slip transition in NiAl occurs from alpha(111) slip to non-alphaaaaaaaaaaa9111) slip at intermediate temperatures. In Ni-50at.% Al single crystal, only alpha(010) dislocations are observed above the slip transition temperature. In contrast, alpha(101)(101) glide has been observed to control deformation beyond the slip transition temperature in Ni-44at.%Al. alpha(101) dislocations are observed primarily along both (111) directions in the glide plane. High-resolution transmission electron microscopy observations show that the core of the alpha(101) dislocations along these directions is decomposed into two alpha(010) dislocations, separated by a distance of approximately 2nm. The temperature window of stability for these alpha(101) dislocations depends upon the strain rate. At a strain rate of 1.4 x 10(exp -4)/s, lpha(101) dislocations are observed between 800 and 1000K. Complete decomposition of a alpha(101) dislocations into alpha(010) dislocations occurs beyond 1000K, leading to alpha(010) climb as the deformation mode at higher temperature. At lower strain rates, decomposition of a alpha(101) dislocations has been observed to occur along the edge orientation at temperatures below 1000K. Embedded-atom method calculations and experimental results indicate that alpha(101) dislocation have a large Peieris stress at low temperature. Based on the present microstructural observations and a survey of the literature with respect to vacancy content and diffusion in NiAl, a model is proposed for alpha(101)(101) glide in Ni-44at.%Al, and for the observed yield strength versus temperature behavior of Ni-Al alloys at intermediate and high temperatures.

  1. Single-source-precursor Synthesis and High-temperature Behavior of SiC Ceramics Containing Boron

    Science.gov (United States)

    Gui, Miaomiao; Fang, Yunhui; Yu, Zhaoju

    2014-12-01

    In this paper, a hyperbranched polyborocarbosilane (HPBCS) was prepared by a one-pot synthesis with Cl2Si(CH3)CH2Cl, Cl3SiCH2Cl and BCl3 as the starting materials. The obtained HPBCS was characterized by GPC, FT-IR and NMR, and was confirmed to have hyperbranched structures. The thermal property of the resulting HPBCS was investigated by TGA. The ceramic yield of the HPBCS is about 84% and that of the counterpart hyperbranched hydridopolycarbosilane is only 45%, indicating that the introduction of boron into the preceramic polymer significantly improved the ceramic yield. With the polymer-derived ceramic route, the final ceramics were annealed at 1800 °C in argon atmosphere for 2 h in order to characterize the microstructure and to evaluate the high-temperature behavior. The final ceramic microstructure was studied by XRD and SEM, indicating that the introduction of boron dramatically inhibits SiC crystallization. The boron-containing SiC ceramic shows excellent high-temperature behavior against decomposition and crystallization at 1800 °C.

  2. Peculiarities of high-amplitude dislocation internal friction in molybdenum single crystals of high purity in the temperature range 5.9 to 300 K

    International Nuclear Information System (INIS)

    Kaufmann, H.J.; Pal-Val, P.P.

    1982-01-01

    Amplitude dependences of internal friction in molybdenum single crystals of the orientations , , , are studied. The residual resistance ratio of the samples is (1 to 2) x 10 5 . The measurements are carried out at the frequency of 88 kHz in the temperature range 5.9 to 300 K. At low temperatures (<= 90 K) a maximum is found in the decrement amplitude dependences the height of which decreases rapidly with decreasing temperature. In this case the maximum position in the amplitude deformation axis does not change. In the same amplitude range a saturation region appears in the modulus defect amplitude dependences the magnitude of which also decreases rapidly with decreasing temperature. The observed behaviour of amplitude-dependent internal friction testifies to the fact that while decreasing temperature the losses connected with dislocation unpinning from the pinning centres decrease sharply. In molybdenum single crystals of lower purity or deformed at room temperature a maximum in the decrement amplitude dependences measured in the same amplitude range is absent. The peculiarities described cannot be explained in the framework of the theories presented. (author)

  3. High temperature refrigerator

    International Nuclear Information System (INIS)

    Steyert, W.A. Jr.

    1978-01-01

    A high temperature magnetic refrigerator is described which uses a Stirling-like cycle in which rotating magnetic working material is heated in zero field and adiabatically magnetized, cooled in high field, then adiabatically demagnetized. During this cycle the working material is in heat exchange with a pumped fluid which absorbs heat from a low temperature heat source and deposits heat in a high temperature reservoir. The magnetic refrigeration cycle operates at an efficiency 70% of Carnot

  4. High temperature refrigerator

    Science.gov (United States)

    Steyert, Jr., William A.

    1978-01-01

    A high temperature magnetic refrigerator which uses a Stirling-like cycle in which rotating magnetic working material is heated in zero field and adiabatically magnetized, cooled in high field, then adiabatically demagnetized. During this cycle said working material is in heat exchange with a pumped fluid which absorbs heat from a low temperature heat source and deposits heat in a high temperature reservoir. The magnetic refrigeration cycle operates at an efficiency 70% of Carnot.

  5. High temperature measuring device

    Science.gov (United States)

    Tokarz, Richard D.

    1983-01-01

    A temperature measuring device for very high design temperatures (to 2,000.degree. C.). The device comprises a homogenous base structure preferably in the form of a sphere or cylinder. The base structure contains a large number of individual walled cells. The base structure has a decreasing coefficient of elasticity within the temperature range being monitored. A predetermined quantity of inert gas is confined within each cell. The cells are dimensionally stable at the normal working temperature of the device. Increases in gaseous pressure within the cells will permanently deform the cell walls at temperatures within the high temperature range to be measured. Such deformation can be correlated to temperature by calibrating similarly constructed devices under known time and temperature conditions.

  6. High-temperature sensor

    Science.gov (United States)

    Not Available

    1981-01-29

    A high temperature sensor is described which includes a pair of electrical conductors separated by a mass of electrical insulating material. The insulating material has a measurable resistivity within the sensor that changes in relation to the temperature of the insulating material within a high temperature range (1000 to 2000/sup 0/K). When required, the sensor can be encased within a ceramic protective coating.

  7. High temperature single crystal diffraction study on monobarium gallate — the crystal structure of β-BaGa 2O 4

    Science.gov (United States)

    Kahlenberg, Volker; Weidenthaler, Claudia

    2002-06-01

    Differential thermal analysis and high temperature single crystal diffraction on monobarium gallate indicate that there is a reversible paraelectric-ferroelectric phase transition at about Tc=770 °C. The crystal structure of the previously unknown paraelectric high temperature modification β-BaGa 2O 4 has been solved from a single crystal data set collected at 800 °C. The compound is isotypic with β-BaAl 2O 4 and closely related with high-kalsilite, adopting space group P6 322 ( a=5.3925(13), c=8.9739(24) Å, V=226.0(1) Å 3, Z=2, Dcalc=5.01 g cm -3, R(| F|)=0.025 for 125 independent reflections with I>2 σ( I) and 13 parameters). Main building element are GaO 4-tetrahedra which are corner linked to form sheets normal to the c axis. These layers are in turn connected to build up a three-dimensional framework enclosing cavities which are occupied by Ba 2+. The bridging oxygen atoms between the layers are statistically distributed over three positions displaced 0.56 Å from the ideal position on the three-fold axis. The off-centering reduces the GaOGa bond angle from an energetically unfavorable 180 to 145.0°. Within a single layer of the high temperature phase the tetrahedra are arranged in six-membered rings with an UDUDUD conformation. A different framework topology is found in the low temperature modification α-BaGa 2O 4 which is based on two different ring configurations, UUUDDD and UDUDUD. Due to the differences between the sequences of upwards and downwards pointing tetrahedra in both phases the α- β transformation is a first order transition showing a pronounced thermal hystereses between heating and cooling. The transition is also reflected in the evolution of the lattice parameters where significant discontinuities are observed at Tc.

  8. Survey of Properties of Key Single and Mixture Halide Salts for Potential Application as High Temperature Heat Transfer Fluids for Concentrated Solar Thermal Power Systems

    Directory of Open Access Journals (Sweden)

    Chao-Jen Li

    2014-04-01

    Full Text Available In order to obtain high energy efficiency in a concentrated solar thermal power plant, more and more high concentration ratio to solar radiation are applied to collect high temperature thermal energy in modern solar power technologies. This incurs the need of a heat transfer fluid being able to work at more and more high temperatures to carry the heat from solar concentrators to a power plant. To develop the third generation heat transfer fluids targeting at a high working temperature at least 800 ℃, a research team from University of Arizona, Georgia Institute of Technology, and Arizona State University proposed to use eutectic halide salts mixtures in order to obtain the desired properties of low melting point, low vapor pressure, great stability at temperatures at least 800 ℃, low corrosion, and favorable thermal and transport properties. In this paper, a survey of the available thermal and transport properties of single and eutectic mixture of several key halide salts is conducted, providing information of great significance to researchers for heat transfer fluid development.

  9. Investigation on defects in the high temperature inorganic scintillation single crystals of Ce:YAlO sub 3

    CERN Document Server

    Zhao Guang Jun; He Xiao Ming; Xu Jun; Tian Yu Lian; Huang Wan Xia

    2002-01-01

    The defects in Ce:YAlO sub 3 single crystals grown by Czochralski method were investigated by transmission white beam synchrotron radiation topography method. It was shown in experiments that the growth striations, inclusions precipitations, twins, core and dislocation group were the main growth defects in Ce:YAP single crystals. The mechanism of the defects formation was also discussed. The results showed that the doped concentration, purity of starting materials and growth conditions are the main causes for defects formation in Ce:YAP single crystals

  10. High temperature pressure gauge

    Science.gov (United States)

    Echtler, J. Paul; Scandrol, Roy O.

    1981-01-01

    A high temperature pressure gauge comprising a pressure gauge positioned in fluid communication with one end of a conduit which has a diaphragm mounted in its other end. The conduit is filled with a low melting metal alloy above the diaphragm for a portion of its length with a high temperature fluid being positioned in the remaining length of the conduit and in the pressure gauge.

  11. High temperature probe

    Science.gov (United States)

    Swan, Raymond A.

    1994-01-01

    A high temperature probe for sampling, for example, smokestack fumes, and is able to withstand temperatures of 3000.degree. F. The probe is constructed so as to prevent leakage via the seal by placing the seal inside the water jacket whereby the seal is not exposed to high temperature, which destroys the seal. The sample inlet of the probe is also provided with cooling fins about the area of the seal to provide additional cooling to prevent the seal from being destroyed. Also, a heated jacket is provided for maintaining the temperature of the gas being tested as it passes through the probe. The probe includes pressure sensing means for determining the flow velocity of an efficient being sampled. In addition, thermocouples are located in various places on the probe to monitor the temperature of the gas passing there through.

  12. Phase diagram and electronic indication of high-temperature superconductivity at 65 K in single-layer FeSe films.

    Science.gov (United States)

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

    2013-07-01

    The recent discovery of possible high-temperature superconductivity in single-layer FeSe films has generated significant experimental and theoretical interest. In both the cuprate and the iron-based high-temperature superconductors, superconductivity is induced by doping charge carriers into the parent compound to suppress the antiferromagnetic state. It is therefore important to establish whether the superconductivity observed in the single-layer sheets of FeSe--the essential building blocks of the Fe-based superconductors--is realized by undergoing a similar transition. Here we report the phase diagram for an FeSe monolayer grown on a SrTiO3 substrate, by tuning the charge carrier concentration over a wide range through an extensive annealing procedure. We identify two distinct phases that compete during the annealing process: the electronic structure of the phase at low doping (N phase) bears a clear resemblance to the antiferromagnetic parent compound of the Fe-based superconductors, whereas the superconducting phase (S phase) emerges with the increase in doping and the suppression of the N phase. By optimizing the carrier concentration, we observe strong indications of superconductivity with a transition temperature of 65±5 K. The wide tunability of the system across different phases makes the FeSe monolayer ideal for investigating not only the physics of superconductivity, but also for studying novel quantum phenomena more generally.

  13. Low-temperature single crystal X-ray diffraction and high-pressure Raman studies on [(CH 3) 2NH 2] 2[SbCl 5

    Science.gov (United States)

    Bujak, Maciej; Angel, Ross J.

    2007-11-01

    The structure of bis(dimethylammonium) pentachloroantimonate(III), [(CH 3) 2NH 2] 2[SbCl 5], BDP, was studied at 15 K and ambient pressure by single-crystal X-ray diffraction as well as at ambient temperature and high pressures up to 4.87(5) GPa by Raman spectroscopy. BDP crystallizes in the orthorhombic Pnma space group with a=8.4069(4), b=11.7973(7), c=14.8496(7) Å, and Z=4; R1=0.0381, w R2=0.0764. The structure consists of distorted [SbCl 6] 3- octahedra forming zig-zag [{SbCl 5} n] 2 n- chains that are cross-linked by dimethylammonium [(CH 3) 2NH 2] + cations. The organic and inorganic substructures are bound together by the N-H…Cl hydrogen bonds. The distortions of [SbCl 6] 3- units increase, partly due to the influence of the hydrogen bonds which became stronger, with decreasing temperature. The preliminary room temperature, high-pressure X-ray diffraction experiments suggest that BDP undergoes a first-order phase transition below ca. 0.44(5) GPa that destroys single-crystal samples. The transition is accompanied by changes in the intensities and positions of the Raman lines below 400 cm -1.

  14. High-temperature operating non-volatile memory of printable single-wall carbon nanotubes self-assembled with a conjugate block copolymer.

    Science.gov (United States)

    Hwang, Sun Kak; Choi, Jae Ryung; Bae, Insung; Hwang, Ihn; Cho, Suk Man; Huh, June; Park, Cheolmin

    2013-03-25

    Printable non-volatile polymer memories are fabricated with solution-processed nanocomposite films of poly(styrene-block-paraphenylene) (PS-b-PPP) and single-wall carbon nanotubes (SWNTs). The devices show stable data retention at high temperatures of up to 100 °C without significant performance degradation due to the strong, non-destructive, and isomorphic π-π interactions between the SWNTs and PPP block. Copyright © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. High-Q energy trapping of temperature-stable shear waves with Lamé cross-sectional polarization in a single crystal silicon waveguide

    Science.gov (United States)

    Tabrizian, R.; Daruwalla, A.; Ayazi, F.

    2016-03-01

    A multi-port electrostatically driven silicon acoustic cavity is implemented that efficiently traps the energy of a temperature-stable eigen-mode with Lamé cross-sectional polarization. Dispersive behavior of propagating and evanescent guided waves in a ⟨100⟩-aligned single crystal silicon waveguide is used to engineer the acoustic energy distribution of a specific shear eigen-mode that is well known for its low temperature sensitivity when implemented in doped single crystal silicon. Such an acoustic energy trapping in the central region of the acoustic cavity geometry and far from substrate obviates the need for narrow tethers that are conventionally used for non-destructive and high quality factor (Q) energy suspension in MEMS resonators; therefore, the acoustically engineered waveguide can simultaneously serve as in-situ self-oven by passing large uniformly distributed DC currents through its body and without any concern about perturbing the mode shape or deforming narrow supports. Such a stable thermo-structural performance besides large turnover temperatures than can be realized in Lamé eigen-modes make this device suitable for implementation of ultra-stable oven-controlled oscillators. 78 MHz prototypes implemented in arsenic-doped single crystal silicon substrates with different resistivity are transduced by in- and out-of-plane narrow-gap capacitive ports, showing high Q of ˜43k. The low resistivity device shows an overall temperature-induced frequency drift of 200 ppm over the range of -20 °C to 80 °C, which is ˜15× smaller compared to overall frequency drift measured for the similar yet high resistivity device in the same temperature range. Furthermore, a frequency tuning of ˜2100 ppm is achieved in high resistivity device by passing 45 mA DC current through its body. Continuous operation of the device under such a self-ovenizing current over 10 days did not induce frequency instability or degradation in Q.

  16. High temperature reaction kinetics

    International Nuclear Information System (INIS)

    Jonah, C.D.; Beno, M.F.; Mulac, W.A.; Bartels, D.

    1985-01-01

    During the last year the dependence of the apparent rate of OD + CO on water pressure was measured at 305, 570, 865 and 1223 K. An explanation was found and tested for the H 2 O dependence of the apparent rate of OH(OD) + CO at high temperatures. The isotope effect for OH(D) with CO was determined over the temperature range 330 K to 1225 K. The reason for the water dependence of the rate of OH(OD) + CO near room temperatures has been investigated but no clear explanation has been found. 1 figure

  17. Coupling between Re segregation and γ/γ′ interfacial dislocations during high-temperature, low-stress creep of a nickel-based single-crystal superalloy

    International Nuclear Information System (INIS)

    Huang, Ming; Cheng, Zhiying; Xiong, Jichun; Li, Jiarong; Hu, Jianqiao; Liu, Zhanli; Zhu, Jing

    2014-01-01

    The synergistic action of local elemental distribution, and in particular Re doping, with interfacial dislocations at the γ/γ′ interface is still one of the most considered and unclear issues during creep of nickel-based single-crystal superalloys. In order to investigate this problem, a detailed characterization of interfacial dislocations in a DD6 superalloy after creep loading for 12 h at high temperature and low stress was carried out using transmission electron microscopy and high-angle annular dark field scanning transmission electron microscopy techniques. In addition, the local elemental distribution near dislocation core regions was determined by energy dispersive X-ray spectroscopy (EDS) mapping. It was found for the first time that three types of interfacial protrusions are formed at the γ/γ′ interface after creep loading for 12 h under conditions of high temperature and low stress and demonstrated that the formation of these features originates from dislocation motion. Additionally, EDS mapping provides evidence for co-segregation of Re with Cr and Co at the tip of the protrusions. Based on this, a model concerning dislocation core structure and dislocation climb was proposed to explain the different morphology of the protrusions. The observations highlight the importance of the coupling between Re segregation and γ/γ′ interfacial dislocations for improving creep properties in nickel-based superalloys. The results of the study will be beneficial for the design of new high-temperature materials and for understanding the origin of the effect of Re additions in nickel-based single-crystal superalloys

  18. Interface high-temperature superconductivity

    Science.gov (United States)

    Wang, Lili; Ma, Xucun; Xue, Qi-Kun

    2016-12-01

    Cuprate high-temperature superconductors consist of two quasi-two-dimensional (2D) substructures: CuO2 superconducting layers and charge reservoir layers. The superconductivity is realized by charge transfer from the charge reservoir layers into the superconducting layers without chemical dopants and defects being introduced into the latter, similar to modulation-doping in the semiconductor superlattices of AlGaAs/GaAs. Inspired by this scheme, we have been searching for high-temperature superconductivity in ultra-thin films of superconductors epitaxially grown on semiconductor/oxide substrates since 2008. We have observed interface-enhanced superconductivity in both conventional and unconventional superconducting films, including single atomic layer films of Pb and In on Si substrates and single unit cell (UC) films of FeSe on SrTiO3 (STO) substrates. The discovery of high-temperature superconductivity with a superconducting gap of ∼20 meV in 1UC-FeSe/STO has stimulated tremendous interest in the superconductivity community, for it opens a new avenue for both raising superconducting transition temperature and understanding the pairing mechanism of unconventional high-temperature superconductivity. Here, we review mainly the experimental progress on interface-enhanced superconductivity in the three systems mentioned above with emphasis on 1UC-FeSe/STO, studied by scanning tunneling microscopy/spectroscopy, angle-resolved photoemission spectroscopy and transport experiments. We discuss the roles of interfaces and a possible pairing mechanism inferred from these studies.

  19. High temperature pipeline design

    Energy Technology Data Exchange (ETDEWEB)

    Greenslade, J.G. [Colt Engineering, Calgary, AB (Canada). Pipelines Dept.; Nixon, J.F. [Nixon Geotech Ltd., Calgary, AB (Canada); Dyck, D.W. [Stress Tech Engineering Inc., Calgary, AB (Canada)

    2004-07-01

    It is impractical to transport bitumen and heavy oil by pipelines at ambient temperature unless diluents are added to reduce the viscosity. A diluted bitumen pipeline is commonly referred to as a dilbit pipeline. The diluent routinely used is natural gas condensate. Since natural gas condensate is limited in supply, it must be recovered and reused at high cost. This paper presented an alternative to the use of diluent to reduce the viscosity of heavy oil or bitumen. The following two basic design issues for a hot bitumen (hotbit) pipeline were presented: (1) modelling the restart problem, and, (2) establishing the maximum practical operating temperature. The transient behaviour during restart of a high temperature pipeline carrying viscous fluids was modelled using the concept of flow capacity. Although the design conditions were hypothetical, they could be encountered in the Athabasca oilsands. It was shown that environmental disturbances occur when the fluid is cooled during shut down because the ground temperature near the pipeline rises. This can change growing conditions, even near deeply buried insulated pipelines. Axial thermal loads also constrain the design and operation of a buried pipeline as higher operating temperatures are considered. As such, strain based design provides the opportunity to design for higher operating temperature than allowable stress based design methods. Expansion loops can partially relieve the thermal stress at a given temperature. As the design temperature increase, there is a point at which above grade pipelines become attractive options, although the materials and welding procedures must be suitable for low temperature service. 3 refs., 1 tab., 10 figs.

  20. High temperature storage loop :

    Energy Technology Data Exchange (ETDEWEB)

    Gill, David Dennis; Kolb, William J.

    2013-07-01

    A three year plan for thermal energy storage (TES) research was created at Sandia National Laboratories in the spring of 2012. This plan included a strategic goal of providing test capability for Sandia and for the nation in which to evaluate high temperature storage (>650ÀC) technology. The plan was to scope, design, and build a flow loop that would be compatible with a multitude of high temperature heat transfer/storage fluids. The High Temperature Storage Loop (HTSL) would be reconfigurable so that it was useful for not only storage testing, but also for high temperature receiver testing and high efficiency power cycle testing as well. In that way, HTSL was part of a much larger strategy for Sandia to provide a research and testing platform that would be integral for the evaluation of individual technologies funded under the SunShot program. DOEs SunShot program seeks to reduce the price of solar technologies to 6/kWhr to be cost competitive with carbon-based fuels. The HTSL project sought to provide evaluation capability for these SunShot supported technologies. This report includes the scoping, design, and budgetary costing aspects of this effort

  1. Highly efficient high temperature electrolysis

    DEFF Research Database (Denmark)

    Hauch, Anne; Ebbesen, Sune; Jensen, Søren Højgaard

    2008-01-01

    electrolysis is favourable from a thermodynamic point of view, because a part of the required energy can be supplied as thermal heat, and the activation barrier is lowered increasing the H-2 production rate. Only two types of cells operating at high temperature (above 200 degrees C) have been described...... electrolysis using SOECs is competitive to H-2 production from fossil fuels at electricity prices below 0.02-0.03 is an element of per kWh. Though promising SOEC results on H-2 production have been reported a substantial R&D is still required to obtain inexpensive, high performing and long-term stable...

  2. Life at High Temperatures

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 10; Issue 9. Life at High Temperatures. Ramesh Maheshwari. General Article Volume 10 Issue 9 September 2005 pp 23-36. Fulltext. Click here to view fulltext PDF. Permanent link: http://www.ias.ac.in/article/fulltext/reso/010/09/0023-0036. Keywords.

  3. High temperature superconductivity: Proceedings

    International Nuclear Information System (INIS)

    Bedell, K.S.; Coffey, D.; Meltzer, D.E.; Pines, D.; Schrieffer, J.R.

    1990-01-01

    This book is the result of a symposium at Los Alamos in 1989 on High Temperature Superconductivity. The topics covered include: phenomenology, quantum spin liquids, spin space fluctuations in the insulating and metallic phases, normal state properties, and numerical studies and simulations. (JF)

  4. High Temperature Electrolysis

    DEFF Research Database (Denmark)

    Elder, Rachael; Cumming, Denis; Mogensen, Mogens Bjerg

    2015-01-01

    High temperature electrolysis of carbon dioxide, or co-electrolysis of carbon dioxide and steam, has a great potential for carbon dioxide utilisation. A solid oxide electrolysis cell (SOEC), operating between 500 and 900. °C, is used to reduce carbon dioxide to carbon monoxide. If steam is also i...

  5. High temperature thermometric phosphors

    Science.gov (United States)

    Allison, Stephen W.; Cates, Michael R.; Boatner, Lynn A.; Gillies, George T.

    1999-03-23

    A high temperature phosphor consists essentially of a material having the general formula LuPO.sub.4 :Dy.sub.(x),Eu.sub.y) wherein: 0.1 wt %.ltoreq.x.ltoreq.20 wt % and 0.1 wt %.ltoreq.y.ltoreq.20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopent. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions.

  6. Revisiting the I{\\overline {\\bf 1}} structures of high-temperature Ca-rich plagioclase feldspar - a single-crystal neutron and X-ray diffraction study.

    Science.gov (United States)

    Jin, Shiyun; Wang, Xiaoping; Xu, Huifang

    2018-04-01

    The I{\\overline 1} structures of four natural Ca-rich plagioclase feldspars formed at high temperature were analysed using single-crystal neutron and X-ray diffraction. The neutron time-of-flight Laue diffractometer at the ORNL Spallation Neutron Source (Tennessee, USA) combined with a single-crystal X-ray diffraction instrument were able to reveal some new details about these already intensively studied structures. The split oxygen atoms refined from the neutron diffraction data show the underlying mechanism of Ca-Na ordering and the anisotropic P{\\overline 1} ordering along the c-axis. The compositional ranges covered by the samples studied are quite rare for I{\\overline 1} structures. The incommensurately modulated e2 structure of some plagioclase samples can easily be confused with an I{\\overline 1} structure from the diffraction pattern, which puts some previously published I{\\overline 1} structures into question. An incomplete phase diagram for Ca-rich plagioclase feldspar is proposed to explain the rarity of the I{\\overline 1} structure in this compositional range, and a time-temperature-transformation diagram for the composition ∼An 66 is provided accordingly.

  7. High-temperature fluxing salt of LiNbO{sub 3} single-crystal by potassium meta-phosphate solvent

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, De-Long, E-mail: dlzhang@tju.edu.cn [Department of Opto-electronics and Information Engineering, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072 (China); Key Laboratory of Optoelectronic Information Technology, Ministry of Education, Tianjin University, Tianjin 300072 (China); Du, Wen-Jie; Gao, Jian; Hua, Ping-Rang [Department of Opto-electronics and Information Engineering, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072 (China); Key Laboratory of Optoelectronic Information Technology, Ministry of Education, Tianjin University, Tianjin 300072 (China); Yu, Zhi-Wu, E-mail: zhiwuyu@hmfl.ac.cn [High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Hefei 230031, Anhui (China); Yu, Dao-Yin [Department of Opto-electronics and Information Engineering, School of Precision Instruments and Opto-electronics Engineering, Tianjin University, Tianjin 300072 (China); Key Laboratory of Optoelectronic Information Technology, Ministry of Education, Tianjin University, Tianjin 300072 (China); Yue-Bun Pun, Edwin [Department of Electronic Engineering, City University of Hong Kong, 83 Tat Chee Avenue, Kowloon, Hong Kong (China)

    2013-12-16

    We report that potassium meta-phosphate (KPO{sub 3}) is an adequate solvent for high-temperature fluxing salt of LiNbO{sub 3} crystal. As the KPO{sub 3} is used as the solvent, the solubility of LiNbO{sub 3} is as high as 3 g g{sup −1} at 1050 °C. The dissolving is fast. Neither solute nor solvent evaporates from the melt during the dissolving procedure. A clear solution is obtained and verified valid for crystal composition analysis using chemical method of inductively coupled plasma atomic emission spectroscopy. To help for understanding the dissolving mechanism, the obtained fluxing melt product was further characterized using X-ray diffraction, nuclear magnetic resonance and Raman scattering spectroscopy. The results show that the melt is amorphous. The P ion in the melt is in the form of low condensation and the Nb ion is likely in the form of Lindqvist ion. Finally, the dissolving mechanism is discussed. - Graphical abstract: An interesting and crucial finding that potassium meta-phosphate (KPO{sub 3}) is an adequate high-temperature solvent for composition analysis of LiNbO{sub 3} optical single-crystal using chemical method. - Highlights: • High-temperature fluxing salt of LiNbO{sub 3} (LN) crystal by KPO{sub 3} solvent is reported. • The solubility of LN is as much as 3 g g{sup −1} at 1050 °C and follows the Van't Hoff law. • The solution obtained is valid for LN composition analysis using chemical method. • The fluxing melt is amorphous with Nb presence in Lindqvist ion and P in free ion. • Flexible P–O bond, opened structure and high viscosity make KPO{sub 3} the adequate solvent.

  8. Solute strengthening at high temperatures

    Science.gov (United States)

    Leyson, G. P. M.; Curtin, W. A.

    2016-08-01

    The high temperature behavior of solute strengthening has previously been treated approximately using various scaling arguments, resulting in logarithmic and power-law scalings for the stress-dependent energy barrier Δ E(τ ) versus stress τ. Here, a parameter-free solute strengthening model is extended to high temperatures/low stresses without any a priori assumptions on the functional form of Δ E(τ ) . The new model predicts that the well-established low-temperature, with energy barrier Δ {{E}\\text{b}} and zero temperature flow stress {τy0} , transitions to a near-logarithmic form for stresses in the regime 0.2intermediate-temperature and the associated transition for the activation volume. Overall, the present analysis unifies the different qualitative models in the literature and, when coupled with the previous parameter-free solute strengthening model, provides a single predictive model for solute strengthening as a function of composition, temperature, and strain rate over the full range of practical utility.

  9. Basic study for a large AC current supply with a single phase air-core Bi2223 high temperature superconducting transformer

    Science.gov (United States)

    Nanato, N.; Kishi, N.; Tanaka, Y.; Kondo, M.

    2017-07-01

    The authors have been developing a compact power supply with a single-phase Bi2223 high temperature superconducting (HTS) transformer. The conventional transformer has an iron-core for enhancing magnetic coupling between its primary coil and secondary one. However, the iron-core has great majority of size and weight of the transformer and therefore it is desirable to be removed for a smaller and lighter transformer. In this paper, the authors propose an air-core HTS transformer for a more compact power supply than the conventional one. As experimental results, it is shown that appropriate design of the air-core transformer has a possibility to decrease the weight and volume of the large AC current supply.

  10. 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 ...

  11. High temperature superconductors

    CERN Document Server

    Paranthaman, Parans

    2010-01-01

    This essential reference provides the most comprehensive presentation of the state of the art in the field of high temperature superconductors. This growing field of research and applications is currently being supported by numerous governmental and industrial initiatives in the United States, Asia and Europe to overcome grid energy distribution issues. The technology is particularly intended for densely populated areas. It is now being commercialized for power-delivery devices, such as power transmission lines and cables, motors and generators. Applications in electric utilities include current limiters, long transmission lines and energy-storage devices that will help industries avoid dips in electric power.

  12. The role of stress relaxation and creep during high temperature deformation in Ni-base single crystal superalloys – Implications to strain build-up during directional solidification

    International Nuclear Information System (INIS)

    D'Souza, Neil; Kelleher, Joe; Qiu, Chunlei; Zhang, Shu-Yan; Gardner, Sam; Jones, Robert E.; Putman, Duncan; Panwisawas, Chinnapat

    2016-01-01

    The study of high temperature deformation of Ni-base superalloys finds a number of applications. In this study we consider how stress/strain resulting from directional solidification can be alleviated through phenomena such as relaxation and how this can be measured. Based on a modelling study, a range of stresses between 550 and 650 MPa were chosen for tensile testing at 900 °C in the Ni-base superalloy, CMSX4. In-situ neutron diffractometry together with ex-situ transmission electron microscopy have been used to study relaxation occurring during high-temperature deformation. The behaviour of (100) and (200) lattice strains with macroscopic stress has been quantitatively analysed for single crystals with axial orientations within 5° from [100]. The (200) γ+γ / fundamental peak has been used to relate the decay in applied macroscopic stress with lattice strain. At high stresses (above 600 MPa), relaxation was particularly pronounced with an immediate appreciable decay in lattice strain (and stress) within 20 min. At lower stresses, significant relaxation is only observed after prolonged hold. Relaxation occurs in both γ and γ / , as confirmed by presence of dislocations within both phases and it was also with minimal lattice rotation (<3°). Also, the decrease in lattice strain from relaxation was at least two/threefold lower than the creep strain, obtained from sample elongation. It is shown that in modelling of strain during solidification, it is important to consider the relaxation of lattice strain, rather than just creep. Implications of this study to the critical plastic strain for re-crystallisation are addressed.

  13. A single-phase all-solid-state lithium battery based on Li1.5Cr0.5Ti1.5(PO4)3for high rate capability and low temperature operation.

    Science.gov (United States)

    Inoishi, Atsushi; Nishio, Akira; Yoshioka, Yuto; Kitajou, Ayuko; Okada, Shigeto

    2018-03-28

    We report a battery made from a single material using Li 1.5 Cr 0.5 Ti 1.5 (PO 4 ) 3 as the anode, cathode and electrolyte. A high rate capability at room temperature and very low-temperature operation (233 K) were possible as a result of the superior ionic conductivity and low interfacial resistance obtained from the single-phase cell design.

  14. Summary: High Temperature Downhole Motor

    Energy Technology Data Exchange (ETDEWEB)

    Raymond, David W. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2017-10-01

    Directional drilling can be used to enable multi-lateral completions from a single well pad to improve well productivity and decrease environmental impact. Downhole rotation is typically developed with a motor in the Bottom Hole Assembly (BHA) that develops drilling power (speed and torque) necessary to drive rock reduction mechanisms (i.e., the bit) apart from the rotation developed by the surface rig. Historically, wellbore deviation has been introduced by a “bent-sub,” located in the BHA, that introduces a small angular deviation, typically less than 3 degrees, to allow the bit to drill off-axis with orientation of the BHA controlled at the surface. The development of a high temperature downhole motor would allow reliable use of bent subs for geothermal directional drilling. Sandia National Laboratories is pursuing the development of a high temperature motor that will operate on either drilling fluid (water-based mud) or compressed air to enable drilling high temperature, high strength, fractured rock. The project consists of designing a power section based upon geothermal drilling requirements; modeling and analysis of potential solutions; and design, development and testing of prototype hardware to validate the concept. Drilling costs contribute substantially to geothermal electricity production costs. The present development will result in more reliable access to deep, hot geothermal resources and allow preferential wellbore trajectories to be achieved. This will enable development of geothermal wells with multi-lateral completions resulting in improved geothermal resource recovery, decreased environmental impact and enhanced well construction economics.

  15. High temperature metallic recuperator

    Science.gov (United States)

    Ward, M. E.; Solmon, N. G.; Smeltzer, C. E.

    1981-06-01

    An industrial 4.5 MM Btu/hr axial counterflow recuperator, fabricated to deliver 1600 F combustion air, was designed to handle rapid cyclic loading, a long life, acceptable costs, and a low maintenance requirement. A cost benefit anlysis of a high temperature waste heat recovery system utilizing the recurperator and components capable of 1600 F combustion air preheat shows that this system would have a payback period of less than two years. Fifteen companies and industrial associations were interviewed and expressed great interest in recuperation in large energy consuming industries. Determination of long term environmental effects on candidate recuperator tubing alloys was completed. Alloys found to be acceptable in the 2200 F flue gas environment of a steel billet reheat furnace, were identified.

  16. High-temperature peridotites - lithospheric or asthenospheric?

    International Nuclear Information System (INIS)

    Hops, J.J.; Gurney, J.J.

    1990-01-01

    High-temperature peridotites by definition yield equilibration temperatures greater than 1100 degrees C. On the basis of temperature and pressure calculations, these high-temperature peridotites are amongst the deepest samples entrained by kimberlites on route to the surface. Conflicting models proposing either a lithospheric or asthenospheric origin for the high-temperature peridotites have been suggested. A detailed study of these xenoliths from a single locality, the Jagersfontein kimberlite in the Orange Free State, has been completed as a means of resolving this controversy. 10 refs., 2 figs

  17. Use of high-resolution melting and melting temperature-shift assays for specific detection and identification of Bacillus anthracis based on single nucleotide discrimination.

    Science.gov (United States)

    Derzelle, Sylviane; Mendy, Christiane; Laroche, Séverine; Madani, Nora

    2011-11-01

    Single nucleotide polymorphisms (SNPs) are important diagnostic markers for the detection and differentiation of Bacillus anthracis. High-Resolution Melting (HRM) and Melting Temperature (Tm)-shift methods are two approaches that enable SNP detection without the need for expensive labeled probes. We evaluated the potential diagnostic capability of those methods to discriminate B. anthracis from the other members of the B. cereus group. Two assays targeting B. anthracis-specific SNPs in the plcR and gyrA genes were designed for each method and used to genotype a panel of 155 Bacilli strains. All B. anthracis isolates (n=65) were correctly and unambiguously identified. Assays also proved to be appropriate for the direct genotyping of biological samples. They could reliably detect B. anthracis in contaminated organs containing as little as 10(3)CFU/ml, corresponding to a few genome equivalents per reaction. The HRM and Tm-shift applications described here represent valuable tools for specific identification of B. anthracis at reduced cost. Copyright © 2011 Elsevier B.V. All rights reserved.

  18. HIGH TEMPERATURE VACUUM MIXER

    Directory of Open Access Journals (Sweden)

    E. D. Chertov

    2015-01-01

    Full Text Available The work is devoted to the creation of a new type of mixer to produce homogeneous mixtures of dissimilar materials applied to recycling of housing and communal services waste. The article describes the design of a dual-chamber device of the original high-temperature vacuum mixer, there investigated the processes occurring in the chambers of such devices. The results of theoretical and experimental research of the process of mixing recycled polyethylene with a mixture of "grinded food waste – Eco wool” are presented. The problem of the optimum choice of bending the curvilinear blades in the working volume of the seal, which is achieved by setting their profile in the form of involute arc of several circles of different radii, is examined . The dependences, allowing to define the limits of the changes of the main mode parameters the angular velocity of rotation of the working body of the mixer using two ways of setting the profile of the curvilinear blade mixer are obtained. Represented design of the mixer is proposed to use for a wide range of tasks associated with the mixing of the components with a strongly pronounced difference of physic al chemical properties and, in particular, in the production of composites out of housing and communal services waste.

  19. Advances in high temperature chemistry

    CERN Document Server

    Eyring, Leroy

    1969-01-01

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

  20. High temperature superconductor accelerator magnets

    NARCIS (Netherlands)

    van Nugteren, J.

    2016-01-01

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding 20T. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and

  1. Thermal expansion behavior of empressite, AgTe: A structural study by means of in situ high-temperature single-crystal X-ray diffraction

    Energy Technology Data Exchange (ETDEWEB)

    Bindi, Luca [Museo di Storia Naturale, sez. di Mineralogia, Universita di Firenze, Via La Pira 4, I-50121 Firenze (Italy)], E-mail: luca.bindi@unifi.it

    2009-04-03

    The crystal structure of empressite, AgTe, a rare silver telluride, has been investigated by in situ X-ray single-crystal diffraction methods within the temperature range 298-463 K. AgTe remains orthorhombic, space group Pmnb (Pnma as standard), and shows only normal thermal expansion over the entire temperature range. The unit-cell parameters show a gradual increase with the increase of temperature. Slight adjustments in the geometry of Ag-tetrahedra and in the crystal-chemical environment of tellurium atoms occur in a continuous way without abrupt structural changes. The coefficients of thermal expansion along various axes are: {alpha}{sub a} = 1.5 x 10{sup -5} K{sup -1}, {alpha}{sub b} = 3.0 x 10{sup -5} K{sup -1}, {alpha}{sub c} = 2.2 x 10{sup -5} K{sup -1}, and the bulk thermal expansion coefficient {alpha}{sub V} is 5.4 x 10{sup -5} K{sup -1} for the temperature range 298-463 K.

  2. 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.)

  3. High Temperature Superconductor Resonator Detectors

    Data.gov (United States)

    National Aeronautics and Space Administration — High Temperature Superconductor (HTS) infrared detectors were studied for years but never matured sufficiently for infusion into instruments. Several recent...

  4. High Temperature Superconductor Machine Prototype

    DEFF Research Database (Denmark)

    Mijatovic, Nenad; Jensen, Bogi Bech; Træholt, Chresten

    2011-01-01

    A versatile testing platform for a High Temperature Superconductor (HTS) machine has been constructed. The stationary HTS field winding can carry up to 10 coils and it is operated at a temperature of 77K. The rotating armature is at room temperature. Test results and performance for the HTS field...

  5. High temperature, single mode, long infrared (λ = 17.8 μm) InAs-based quantum cascade lasers

    Energy Technology Data Exchange (ETDEWEB)

    Chastanet, D.; Bousseksou, A., E-mail: adel.bousseksou@u-psud.fr; Julien, F. H.; Colombelli, R., E-mail: raffaele.colombelli@u-psud.fr [Institut d' Electronique Fondamentale, Univ. Paris Sud, UMR 8622 CNRS, 91405 Orsay (France); Lollia, G.; Bahriz, M.; Baranov, A. N.; Teissier, R., E-mail: roland.teissier@ies.univ-montp2.fr [Institut d' Electronique du Sud, Univ. Montpellier 2, UMR 5214 CNRS, 34095 Montpellier (France)

    2014-09-15

    We demonstrate quantum cascade lasers in the InAs/AlSb material system which operate up to 333 K (in pulsed regime) at λ = 17.8 μm. They employ metal-metal optical waveguides and the threshold current density is 1.6 kA/cm{sup 2} at 78 K. We also report distributed-feedback devices obtained using the same laser material via a 1{sup st}-order Bragg grating inscribed in the sole top metallic contact. Spectral single mode operation with more than 20 dB side mode suppression ratio is achieved at a temperature of 300 K. Large wavelength tuning rates, of the order of 1.5 nm/K, are demonstrated. A wavelength coverage of 0.38 μm is achieved in single-mode regime over a temperature range of 255 K.

  6. Epataxial growth of the high-temperature superconductors YBa2Cu3O7-x on silicon single crystals with buffer layers

    International Nuclear Information System (INIS)

    Lubig, A.

    1991-09-01

    In this work the growth of thin films of the high-temperature superconductor YBa 2 Cu 3 O 7-x on Si(001) substrates has been investigated by Rutherford backscattering, channeling, X-ray diffraction, high resolution transmission electron microscopy, and electrical measurements. Epitaxial buffer layers of electrically insulating, pure and yttria-stabilized ZrO 2 ([Y 2 O 3 ] 0.06 [ZrO 2 ] 0.94 = YSZ) as well as of metallic CoSi 2 were employed to largely prevent the interdiffusion and chemical reaction between the superconductor film and the substrate in spite of the high deposition temperatures of the YBa 2 Cu 3 O 7-x in the range of 600 to 800deg C. (orig.)

  7. Nanoscale temperature sensing using single defects in diamond

    International Nuclear Information System (INIS)

    Philipp Neumann

    2014-01-01

    We experimentally demonstrate a novel nanoscale temperature sensing technique that is based on single atomic defects in diamonds, namely nitrogen vacancy color centers. Sample sizes range from millimeter down to a few tens of nanometers. In particular nanodiamonds were used as dispersed probes to acquire spatially resolved temperature profiles utilizing the sensitivity of the optically accessible electron spin level structure we achieve a temperature noise floor of 5mK/Mhz for bulk diamond and 130mK/Mhz for nanodiamonds and accuracies of 1mK. To this end we have developed a new decoupling technique in order to suppress to otherwise limiting effect of magnetic field fluctuations. In addition, high purity isotopically enriched 12C artificial diamonds is used. The high sensitivity to temperature changes adds to the well studied sensitivities to magnetic and electric fields and makes NV diamond a multipurpose nanoprobe. (author)

  8. Flux free growth of large FeSe1/2Te1/2 superconducting single crystals by an easy high temperature melt and slow cooling method

    Directory of Open Access Journals (Sweden)

    P. K. Maheshwari

    2015-09-01

    Full Text Available We report successful growth of flux free large single crystals of superconducting FeSe1/2Te1/2 with typical dimensions of up to few cm. The AC and DC magnetic measurements revealed the superconducting transition temperature (Tc value of around 11.5K and the isothermal MH showed typical type-II superconducting behavior. The lower critical field (Hc1 being estimated by measuring the low field isothermal magnetization in superconducting regime is found to be above 200Oe at 0K. The temperature dependent electrical resistivity ρ(T  showed the Tc (onset to be 14K and the Tc(ρ = 0 at 11.5K. The electrical resistivity under various magnetic fields i.e., ρ(TH for H//ab and H//c demonstrated the difference in the width of Tc with applied field of 14Tesla to be nearly 2K, confirming the anisotropic nature of superconductivity. The upper critical and irreversibility fields at absolute zero temperature i.e., Hc2(0 and Hirr(0 being determined by the conventional one-band Werthamer–Helfand–Hohenberg (WHH equation for the criteria of normal state resistivity (ρn falling to 90% (onset, and 10% (offset is 76.9Tesla, and 37.45Tesla respectively, for H//c and 135.4Tesla, and 71.41Tesla respectively, for H//ab. The coherence length at the zero temperature is estimated to be above 20Å ´ by using the Ginsburg-Landau theory. The activation energy for the FeSe1/2Te1/2 in both directions H//c and H//ab is determined by using Thermally Activation Flux Flow (TAFF model.

  9. High Temperature Electrostrictive Ceramics Project

    Data.gov (United States)

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

  10. Room temperature synthesis of ultra-small, near-unity single-sized lead halide perovskite quantum dots with wide color emission tunability, high color purity and high brightness

    Science.gov (United States)

    Peng, Lucheng; Geng, Jing; Ai, Lisha; Zhang, Ying; Xie, Renguo; Yang, Wensheng

    2016-08-01

    Phosphor with extremely narrow emission line widths, high brightness, and wide color emission tunability in visible regions is required for display and lighting applications, yet none has been reported in the literature so far. In the present study, single-sized lead halide perovskite (APbX 3; A = CH3NH3 and Cs; X = Cl, Br, and I) nanocrystalline (NC) phosphors were achieved for the first time in a one-pot reaction at room temperature (25 °C). The size-dependent samples, which included four families of CsPbBr3 NCs and exhibited sharp excitonic absorption peaks and pure band gap emission, were directly obtained by simply varying the concentration of ligands. The continuity of the optical spectrum can be successively tuned over the entire UV-visible spectral region (360-610 nm) by preparing CsPbCl3, CsPbI3, and CsPb(Y/Br)3 (Y = Cl and I) NCs with the use of CsPbBr3 NCs as templates by anion exchange while maintaining the size of NCs and high quantum yields of up to 80%. Notably, an emission line width of 10-24 nm, which is completely consistent with that of their single particles, indicates the formation of single-sized NCs. The versatility of the synthetic strategy was validated by extending it to the synthesis of single-sized CH3NH3PbX 3 NCs by simply replacing the cesium precursor by the CH3NH3 X precursor.

  11. High temperature crystalline superconductors from crystallized glasses

    Science.gov (United States)

    Shi, Donglu

    1992-01-01

    A method of preparing a high temperature superconductor from an amorphous phase. The method involves preparing a starting material of a composition of Bi.sub.2 Sr.sub.2 Ca.sub.3 Cu.sub.4 Ox or Bi.sub.2 Sr.sub.2 Ca.sub.4 Cu.sub.5 Ox, forming an amorphous phase of the composition and heat treating the amorphous phase for particular time and temperature ranges to achieve a single phase high temperature superconductor.

  12. HIGH TEMPERATURE POLYMER FUEL CELLS

    DEFF Research Database (Denmark)

    Jensen, Jens Oluf; Qingfeng, Li; He, Ronghuan

    2003-01-01

    This paper will report recent results from our group on polymer fuel cells (PEMFC) based on the temperature resistant polymer polybenzimidazole (PBI), which allow working temperatures up to 200°C. The membrane has a water drag number near zero and need no water management at all. The high working...

  13. Development of high strength, high temperature ceramics

    Science.gov (United States)

    Hall, W. B.

    1982-01-01

    Improvement in the high-pressure turbopumps, both fuel and oxidizer, in the Space Shuttle main engine were considered. The operation of these pumps is limited by temperature restrictions of the metallic components used in these pumps. Ceramic materials that retain strength at high temperatures and appear to be promising candidates for use as turbine blades and impellers are discussed. These high strength materials are sensitive to many related processing parameters such as impurities, sintering aids, reaction aids, particle size, processing temperature, and post thermal treatment. The specific objectives of the study were to: (1) identify and define the processing parameters that affect the properties of Si3N4 ceramic materials, (2) design and assembly equipment required for processing high strength ceramics, (3) design and assemble test apparatus for evaluating the high temperature properties of Si3N4, and (4) conduct a research program of manufacturing and evaluating Si3N4 materials as applicable to rocket engine applications.

  14. 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...

  15. High temperature structural insulating material

    Science.gov (United States)

    Chen, W.Y.

    1984-07-27

    A high temperature structural insulating material useful as a liner for cylinders of high temperature engines through the favorable combination of high service temperature (above about 800/sup 0/C), low thermal conductivity (below about 0.2 W/m/sup 0/C), and high compressive strength (above about 250 psi). The insulating material is produced by selecting hollow ceramic beads with a softening temperature above about 800/sup 0/C, a diameter within the range of 20-200 ..mu..m, and a wall thickness in the range of about 2 to 4 ..mu..m; compacting the beads and a compatible silicate binder composition under pressure and sintering conditions to provide the desired structural form with the structure having a closed-cell, compact array of bonded beads.

  16. InGaN High Temperature Photovoltaic Cells, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The objective of this Phase I project is to demonstrate InGaN materials are appropriate for high operating temperature single junction solar cells. Single junction...

  17. High temperature divertor plasma operation

    International Nuclear Information System (INIS)

    Ohyabu, Nobuyoshi.

    1991-02-01

    High temperature divertor plasma operation has been proposed, which is expected to enhance the core energy confinement and eliminates the heat removal problem. In this approach, the heat flux is guided through divertor channel to a remote area with a large target surface, resulting in low heat load on the target plate. This allows pumping of the particles escaping from the core and hence maintaining of the high divertor temperature, which is comparable to the core temperature. The energy confinement is then determined by the diffusion coefficient of the core plasma, which has been observed to be much lower than the thermal diffusivity. (author)

  18. High temperature corrosion of metals

    International Nuclear Information System (INIS)

    Quadakkers, W.J.; Schuster, H.; Ennis, P.J.

    1988-08-01

    This paper covers three main topics: 1. high temperature oxidation of metals and alloys, 2. corrosion in sulfur containing environments and 3. structural changes caused by corrosion. The following 21 subjects are discussed: Influence of implanted yttrium and lanthanum on the oxidation behaviour of beta-NiA1; influence of reactive elements on the adherence and protective properties of alumina scales; problems related to the application of very fine markers in studying the mechanism of thin scale formation; oxidation behaviour of chromia forming Co-Cr-Al alloys with or without reactive element additions; growth and properties of chromia-scales on high-temperature alloys; quantification of the depletion zone in high temperature alloys after oxidation in process gas; effects of HC1 and of N2 in the oxidation of Fe-20Cr; investigation under nuclear safety aspects of Zircaloy-4 oxidation kinetics at high temperatures in air; on the sulfide corrosion of metallic materials; high temperature sulfide corrosion of Mn, Nb and Nb-Si alloys; corrosion behaviour or NiCrAl-based alloys in air and air-SO2 gas mixtures; sulfidation of cobalt at high temperatures; preoxidation for sulfidation protection; fireside corrosion and application of additives in electric utility boilers; transport properties of scales with complex defect structures; observations of whiskers and pyramids during high temperature corrosion of iron in SO2; corrosion and creep of alloy 800H under simulated coal gasification conditions; microstructural changes of HK 40 cast alloy caused by exploitation in tubes in steam reformer installation; microstructural changes during exposure in corrosive environments and their effect on mechanical properties; coatings against carburization; mathematical modeling of carbon diffusion and carbide precipitation in Ni-Cr-based alloys. (MM)

  19. High-temperature solution growth and characterization of (1-x)PbTiO3-xBi(Zn2/3Nb1/3)O3 piezo-/ferroelectric single crystals

    Science.gov (United States)

    Paterson, Alisa R.; Zhao, Jinyan; Liu, Zenghui; Wu, Xiaoqing; Ren, Wei; Ye, Zuo-Guang

    2018-03-01

    Complex perovskite PbTiO3-Bi(Me‧Me″)O3 solid solutions represent new materials systems that possess a higher Curie temperature (TC) than the relaxor-PbTiO3 solid solutions, and are useful for potential applications. To this end, novel ferroelectric single crystals of the (1-x)PbTiO3-xBi(Zn2/3Nb1/3)O3 (PT-BZN) solid solution were successfully grown by the high-temperature solution growth (HTSG) method. Powder X-ray diffraction shows that the symmetry of the grown crystals is tetragonal. The dielectric permittivity and optical domain structures were characterized by dielectric measurements and polarized light microscopy, respectively, as a function of temperature, revealing a first-order ferroelectric-paraelectric phase transition at a TC of 436 ± 2 °C. Based on the TC, the average composition of the crystal platelet was estimated to be 0.58PT-0.42BZN. Piezoresponse force microscopy measurements of the phase and amplitude as a function of voltage reveal the complex polar domain structure and demonstrate the ferroelectric switching behaviour of these materials. These results suggest that the PT-BZN single crystals indeed form a new family of high TC piezo-/ferroelectric materials which are potentially useful for the fabrication of electromechanical transducers for high-temperature applications.

  20. High Performance Single Nanowire Tunnel Diodes

    DEFF Research Database (Denmark)

    Wallentin, Jesper; Persson, Johan Mikael; Wagner, Jakob Birkedal

    Semiconductor nanowires (NWs) have emerged as a promising technology for future electronic and optoelectronic devices. Epitaxial growth of III-V materials on Si substrates have been demonstrated, allowing for low-cost production. As the lattice matching requirements are much less strict than...... for planar growth, many new materials combinations can be grown in a single NW. This opens up exciting opportunities for NW-based high-performance solar cells, where previously inaccessible materials combinations can now be chosen to match the solar spectrum. A key component of a multi-junction solar cell...... NWs were contacted in a NW-FET setup. Electrical measurements at room temperature display typical tunnel diode behavior, with a Peak-to-Valley Current Ratio (PVCR) as high as 8.2 and a peak current density as high as 329 A/cm2. Low temperature measurements show improved PVCR of up to 27.6....

  1. Nuclear shell effects at high temperatures

    International Nuclear Information System (INIS)

    Davidson, N.J.; Miller, H.G.

    1993-01-01

    In discussing the disappearance of nuclear shell effects at high temperatures, it is important to distinguish between the ''smearing out'' of the single-particle spectrum with increasing temperature and the vanishing of shell related structures in many-body quantities such as the excitation energy per nucleon. We propose a semiempirical method to obtain an upper bound on the temperature required to smooth the single-particle spectrum, and point out that shell effects in many-body parameters may persist above this temperature. We find that the temperature required to smear out the single-particle spectrum is approximately 1 MeV for heavy nuclei (A approx-gt 150) and about 3--4 MeV for light nuclei (A approx-lt 50), in reasonable agreement with the estimate of 41/πA 1/3 obtained from calculations with harmonic oscillator potentials. These temperatures correspond to many-body excitation energies of approximately 20 and 60 MeV, respectively

  2. RPC operation at high temperature

    CERN Document Server

    Aielli, G; Cardarelli, R; Di Ciaccio, A; Di Stante, L; Liberti, B; Paoloni, A; Pastori, E; Santonico, R

    2003-01-01

    The resistive electrodes of RPCs utilised in several current experiments (ATLAS, CMS, ALICE, BABAR and ARGO) are made of phenolic /melaminic polymers, with room temperature resistivities ranging from 10**1**0 Omega cm, for high rate operation in avalanche mode, to 5 multiplied by 10**1**1 Omega cm, for streamer mode operation at low rate. The resistivity has however a strong temperature dependence, decreasing exponentially with increasing temperature. We have tested several RPCs with different electrode resistivities in avalanche as well as in streamer mode operation. The behaviours of the operating current and of the counting rate have been studied at different temperatures. Long-term operation has also been studied at T = 45 degree C and 35 degree C, respectively, for high and low resistivity electrodes RPCs.

  3. Temperature optimization of high con

    Science.gov (United States)

    Sabry, M.

    2016-06-01

    Active cooling is essential for solar cells operating under high optical concentration ratios. A system comprises four solar cells that are in thermal contact on top of a copper tube is proposed. Water is flowing inside the tube in order to reduce solar cells temperature for increasing their performance. Computational Fluid Dynamics (CFD) simulation of such system has been performed in order to investigate the effect of water flow rate, tube internal diameter, and convective heat transfer coefficient on the temperature of the solar cells. It is found that increasing convective heat transfer coefficient has a significant effect on reducing solar cells temperatures operating at low flow rates and high optical concentration ratios. Also, a further increase of water flow rate has no effect on reducing cells temperatures.

  4. Temperature optimization of high con

    Directory of Open Access Journals (Sweden)

    M. Sabry

    2016-06-01

    Full Text Available Active cooling is essential for solar cells operating under high optical concentration ratios. A system comprises four solar cells that are in thermal contact on top of a copper tube is proposed. Water is flowing inside the tube in order to reduce solar cells temperature for increasing their performance. Computational Fluid Dynamics (CFD simulation of such system has been performed in order to investigate the effect of water flow rate, tube internal diameter, and convective heat transfer coefficient on the temperature of the solar cells. It is found that increasing convective heat transfer coefficient has a significant effect on reducing solar cells temperatures operating at low flow rates and high optical concentration ratios. Also, a further increase of water flow rate has no effect on reducing cells temperatures.

  5. High temperature electronic gain device

    International Nuclear Information System (INIS)

    McCormick, J.B.; Depp, S.W.; Hamilton, D.J.; Kerwin, W.J.

    1979-01-01

    An integrated thermionic device suitable for use in high temperature, high radiation environments is described. Cathode and control electrodes are deposited on a first substrate facing an anode on a second substrate. The substrates are sealed to a refractory wall and evacuated to form an integrated triode vacuum tube

  6. High temperature and pressure electrochemical test station

    DEFF Research Database (Denmark)

    Chatzichristodoulou, Christodoulos; Allebrod, Frank; Mogensen, Mogens Bjerg

    2013-01-01

    An electrochemical test station capable of operating at pressures up to 100 bars and temperatures up to 400 ◦C has been established. It enables control of the partial pressures and mass flow of O2, N2, H2, CO2, and H2O in a single or dual environment arrangement, measurements with highly corrosive......, to the electrochemical characterization of high temperature and pressure alkaline electrolysis cells and the use of pseudo-reference electrodes for the separation of each electrode contribution. A future perspective of various electrochemical processes and devices that can be developed with the use of the established...

  7. 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

  8. Moire interferometry at high temperatures

    Science.gov (United States)

    Wu, Jau-Je

    1992-01-01

    The objective of this study was to provide an optical technique allowing full-field in-plane deformation measurements at high temperature by using high-sensitivity moire interferometry. This was achieved by a new approach of performing deformation measurements at high temperatures in a vacuum oven using an achromatic interferometer. The moire system setup was designed with particular consideration for the stability, compactness, flexibility, and ease of control. A vacuum testing environment was provided to minimize the instability of the patterns by protecting the optical instruments from the thermal convection currents. Also, a preparation procedure for the high-temperature specimen grating was developed with the use of the plasma-etched technique. Gold was used as a metallic layer in this procedure. This method was demonstrated on a ceramic block, metal/matrix composite, and quartz. Thermal deformation of a quartz specimen was successfully measured in vacuum at 980 degrees Celsius, with the sensitivity of 417 nm per fringe. The stable and well-defined interference patterns confirmed the feasibility of the developments, including the high-temperature moire system and high-temperature specimen grating. The moire system was demonstrated to be vibration-insensitive. Also, the contrast of interference fringes at high temperature was enhanced by means of a spatial filter and a narrow band interference filter to minimize the background noise from the flow of the specimen and heater. The system was verified by a free thermal expansion test of an aluminum block. Good agreement demonstrated the validity of the optical design. The measurements of thermal deformation mismatch were performed on a graphite/epoxy composite, a metal/matrix composite equipped with an optical fiber, and a cutting tool bit. A high-resolution data-reduction technique was used to measure the strain distribution of the cutting tool bit.

  9. High temperature superconductor current leads

    Science.gov (United States)

    Hull, John R.; Poeppel, Roger B.

    1995-01-01

    An electrical lead having one end for connection to an apparatus in a cryogenic environment and the other end for connection to an apparatus outside the cryogenic environment. The electrical lead includes a high temperature superconductor wire and an electrically conductive material distributed therein, where the conductive material is present at the one end of the lead at a concentration in the range of from 0 to about 3% by volume, and at the other end of the lead at a concentration of less than about 20% by volume. Various embodiments are shown for groups of high temperature superconductor wires and sheaths.

  10. High temperature corrosion in gasifiers

    Directory of Open Access Journals (Sweden)

    Bakker Wate

    2004-01-01

    Full Text Available Several commercial scale coal gasification combined cycle power plants have been built and successfully operated during the last 5-10 years. Supporting research on materials of construction has been carried out for the last 20 years by EPRI and others. Emphasis was on metallic alloys for heat exchangers and other components in contact with hot corrosive gases at high temperatures. In this paper major high temperature corrosion mechanisms, materials performance in presently operating gasifiers and future research needs will be discussed.

  11. "Green" High-Temperature Polymers

    Science.gov (United States)

    Meador, Michael A.

    1998-01-01

    PMR-15 is a processable, high-temperature polymer developed at the NASA Lewis Research Center in the 1970's principally for aeropropulsion applications. Use of fiber-reinforced polymer matrix composites in these applications can lead to substantial weight savings, thereby leading to improved fuel economy, increased passenger and payload capacity, and better maneuverability. PMR-15 is used fairly extensively in military and commercial aircraft engines components seeing service temperatures as high as 500 F (260 C), such as the outer bypass duct for the F-404 engine. The current world-wide market for PMR-15 materials (resins, adhesives, and composites) is on the order of $6 to 10 million annually.

  12. In situ temperature monitoring in single-molecule FRET experiments

    Science.gov (United States)

    Hartmann, Andreas; Berndt, Frederic; Ollmann, Simon; Krainer, Georg; Schlierf, Michael

    2018-03-01

    Thermodynamic properties of single molecules including enthalpic and entropic contributions are often determined from experiments by a direct control and precise measurement of the local temperature. However, common temperature monitoring techniques using, for example, ultrafine temperature probes can lead to uncertainties as the probe cannot be placed in the vicinity of the molecule of interest. Here, we devised an approach to measure the local temperature in freely diffusing confocal single-molecule Förster Resonance Energy Transfer (smFRET) experiments in situ by directly adding the temperature-sensitive fluorescent dye Rhodamine B, whose fluorescence lifetime serves as a probe of the local temperature in the confocal volume. We demonstrate that the temperature and FRET efficiencies of static and dynamic molecules can be extracted within one measurement simultaneously, without the need of a reference chamber. We anticipate this technique to be particularly useful in the physicochemical analyses of temperature-dependent biomolecular processes from single-molecule measurements.

  13. Chemistry of high temperature superconductors

    CERN Document Server

    1991-01-01

    This review volume contains the most up-to-date articles on the chemical aspects of high temperature oxide superconductors. These articles are written by some of the leading scientists in the field and includes a comprehensive list of references. This is an essential volume for researchers working in the fields of ceramics, materials science and chemistry.

  14. High temperature component life assessment

    CERN Document Server

    Webster, G A

    1994-01-01

    The aim of this book is to investigate and explain the rapid advances in the characterization of high temperature crack growth behaviour which have been made in recent years, with reference to industrial applications. Complicated mathematics has been minimized with the emphasis placed instead on finding solutions using simplified procedures without the need for complex numerical analysis.

  15. High Temperature, High Power Piezoelectric Composite Transducers

    Directory of Open Access Journals (Sweden)

    Hyeong Jae Lee

    2014-08-01

    Full Text Available Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

  16. High Temperature, High Power Piezoelectric Composite Transducers

    Science.gov (United States)

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, StewarT.

    2014-01-01

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined. PMID:25111242

  17. High temperature, high power piezoelectric composite transducers.

    Science.gov (United States)

    Lee, Hyeong Jae; Zhang, Shujun; Bar-Cohen, Yoseph; Sherrit, Stewart

    2014-08-08

    Piezoelectric composites are a class of functional materials consisting of piezoelectric active materials and non-piezoelectric passive polymers, mechanically attached together to form different connectivities. These composites have several advantages compared to conventional piezoelectric ceramics and polymers, including improved electromechanical properties, mechanical flexibility and the ability to tailor properties by using several different connectivity patterns. These advantages have led to the improvement of overall transducer performance, such as transducer sensitivity and bandwidth, resulting in rapid implementation of piezoelectric composites in medical imaging ultrasounds and other acoustic transducers. Recently, new piezoelectric composite transducers have been developed with optimized composite components that have improved thermal stability and mechanical quality factors, making them promising candidates for high temperature, high power transducer applications, such as therapeutic ultrasound, high power ultrasonic wirebonding, high temperature non-destructive testing, and downhole energy harvesting. This paper will present recent developments of piezoelectric composite technology for high temperature and high power applications. The concerns and limitations of using piezoelectric composites will also be discussed, and the expected future research directions will be outlined.

  18. Amplitude dependent damping in single crystalline high purity molybdenum

    International Nuclear Information System (INIS)

    Zelada-Lambri, G.I; Lambri, O.A; Garcia, J.A; Lomer, J.N

    2004-01-01

    Amplitude dependent damping measurements were performed on high purity single crystalline molybdenum at several different constant temperatures between room temperature and 1273K. The employed samples were single crystals with the orientation, having a residual resistivity ratio of about 8000. Previously to the amplitude dependent damping tests, the samples were subjected to different thermomechanical histories. Amplitude dependent damping effects appear only during the first heating run in temperature where the samples have the thermomechanical state of the deformation process at room temperature. In the subsequent run-ups in temperature, i.e, after subsequent annealings, amplitude dependent damping effects were not detected (au)

  19. NSTX High Temperature Sensor Systems

    International Nuclear Information System (INIS)

    McCormack, B.; Kugel, H.W.; Goranson, P.; Kaita, R.

    1999-01-01

    The design of the more than 300 in-vessel sensor systems for the National Spherical Torus Experiment (NSTX) has encountered several challenging fusion reactor diagnostic issues involving high temperatures and space constraints. This has resulted in unique miniature, high temperature in-vessel sensor systems mounted in small spaces behind plasma facing armor tiles, and they are prototypical of possible high power reactor first-wall applications. In the Center Stack, Divertor, Passive Plate, and vessel wall regions, the small magnetic sensors, large magnetic sensors, flux loops, Rogowski Coils, thermocouples, and Langmuir Probes are qualified for 600 degrees C operation. This rating will accommodate both peak rear-face graphite tile temperatures during operations and the 350 degrees C bake-out conditions. Similar sensor systems including flux loops, on other vacuum vessel regions are qualified for 350 degrees C operation. Cabling from the sensors embedded in the graphite tiles follows narrow routes to exit the vessel. The detailed sensor design and installation methods of these diagnostic systems developed for high-powered ST operation are discussed

  20. High temperature two component explosive

    Science.gov (United States)

    Mars, James E.; Poole, Donald R.; Schmidt, Eckart W.; Wang, Charles

    1981-01-01

    A two component, high temperature, thermally stable explosive composition comprises a liquid or low melting oxidizer and a liquid or low melting organic fuel. The oxidizer and fuel in admixture are incapable of substantial spontaneous exothermic reaction at temperatures on the order of 475.degree. K. At temperatures on the order of 475.degree. K., the oxidizer and fuel in admixture have an activation energy of at least about 40 kcal/mol. As a result of the high activation energy, the preferred explosive compositions are nondetonable as solids at ambient temperature, and become detonable only when heated beyond the melting point. Preferable oxidizers are selected from alkali or alkaline earth metal nitrates, nitrites, perchlorates, and/or mixtures thereof. Preferred fuels are organic compounds having polar hydrophilic groups. The most preferred fuels are guanidinium nitrate, acetamide and mixtures of the two. Most preferred oxidizers are eutectic mixtures of lithium nitrate, potassium nitrate and sodium nitrate, of sodium nitrite, sodium nitrate and potassium nitrate, and of potassium nitrate, calcium nitrate and sodium nitrate.

  1. Motor for High Temperature Applications

    Science.gov (United States)

    Roopnarine (Inventor)

    2013-01-01

    A high temperature motor has a stator with poles formed by wire windings, and a rotor with magnetic poles on a rotor shaft positioned coaxially within the stator. The stator and rotor are built up from stacks of magnetic-alloy laminations. The stator windings are made of high temperature magnet wire insulated with a vitreous enamel film, and the wire windings are bonded together with ceramic binder. A thin-walled cylinder is positioned coaxially between the rotor and the stator to prevent debris from the stator windings from reaching the rotor. The stator windings are wound on wire spools made of ceramic, thereby avoiding need for mica insulation and epoxy/adhesive. The stator and rotor are encased in a stator housing with rear and front end caps, and rear and front bearings for the rotor shaft are mounted on external sides of the end caps to keep debris from the motor migrating into the bearings' races.

  2. Decoherence Assisted Single Electron Trapping at Room Temperature

    Science.gov (United States)

    Elhalawany, Ahmed; Leuenberger, Michael

    2012-02-01

    In this work, we theoretically investigate electron transport in heterostructure semiconductor nanowire (NW). We develop a new mechanism to trap an electron in a quantum dot (QD) by means of decoherence. There are six QDs in the NW. Bias voltage (Vb) is applied across the NW and gate voltage (Vg) is applied to the auxiliary QD to control single charge tunneling. The single electron dynamics along the NW is calculated by means of the generalized master equation based on the tight binding model taking into account electron LO phonon interaction (ELOPI) and thermal broadening inside the QDs. It is shown that the decoherence, which is in the pico-second (ps) regime, speeds up the trapping of the electron in the central QD with probability of 70% in less than 2 ps. Our results can be used for the implementation of high temperature single photon source (SPS) or single electron transistor (SET). We acknowledge support from NSF (Grant No. ECCS-0725514), DARPA/MTO (Grant No. HR0011-08-1-0059), NSF (Grant No. ECCS-0901784), AFOSR (Grant No. FA9550-09-1-0450), and NSF (Grant No. ECCS-1128597).

  3. Design of Water Temperature Control System Based on Single Chip Microcomputer

    Science.gov (United States)

    Tan, Hanhong; Yan, Qiyan

    2017-12-01

    In this paper, we mainly introduce a multi-function water temperature controller designed with 51 single-chip microcomputer. This controller has automatic and manual water, set the water temperature, real-time display of water and temperature and alarm function, and has a simple structure, high reliability, low cost. The current water temperature controller on the market basically use bimetal temperature control, temperature control accuracy is low, poor reliability, a single function. With the development of microelectronics technology, monolithic microprocessor function is increasing, the price is low, in all aspects of widely used. In the water temperature controller in the application of single-chip, with a simple design, high reliability, easy to expand the advantages of the function. Is based on the appeal background, so this paper focuses on the temperature controller in the intelligent control of the discussion.

  4. On supersymmetry at high temperature

    International Nuclear Information System (INIS)

    Bajc, B.; Senjanovic, G.; Melfo, A.

    1996-08-01

    While it is possible to find examples of field theories with a spontaneously broken symmetry at high temperature, in renormalizable supersymmetric models any internal symmetry always get restored. Recently, a counterexample was suggested in the context of nonrenormalizable supersymmetric theories. We show that non negligible higher loop effects actually restore the symmetry, without compromising the validity of perturbation theory. We give some arguments as to why the proposed mechanism should not work in general. (author). 13 refs, 1 fig

  5. Studies at IBM on anisotropy in single crystals of the high-temperature oxide superconductor Y1Ba2Cu3O7/sub -//sub x/ (invited)

    International Nuclear Information System (INIS)

    Gallagher, W.J.

    1988-01-01

    A series of studies carried out at IBM on the magnetic, transport, and optical properties of single crystal Y 1 Ba 2 Cu 3 O/sub 7-//sub x/ demonstrate the overriding importance of anisotropy in its superconducting and normal-state properties

  6. L12-phase cutting during high temperature and low stress creep of a Re-containing Ni-base single crystal superalloy

    Czech Academy of Sciences Publication Activity Database

    Kostka, A.; Maelzer, G. (ed.); Eggeler, G.; Dlouhý, Antonín; Reese, S.; Mack, T.

    2007-01-01

    Roč. 42, č. 11 (2007), s. 3951-3957 ISSN 0022-2461 Institutional research plan: CEZ:AV0Z20410507 Keywords : nickel-base superalloys * single crystals * creep Subject RIV: JG - Metallurgy Impact factor: 1.081, year: 2007

  7. High pressure and high temperature apparatus

    Science.gov (United States)

    Voronov, Oleg A.

    2005-09-13

    A design for high pressure/high temperature apparatus and reaction cell to achieve .about.30 GPa pressure in .about.1 cm volume and .about.100 GPa pressure in .about.1 mm volumes and 20-5000.degree. C. temperatures in a static regime. The device includes profiled anvils (28) action on a reaction cell (14, 16) containing the material (26) to be processed. The reaction cell includes a heater (18) surrounded by insulating layers and screens. Surrounding the anvils are cylindrical inserts and supporting rings (30-48) whose hardness increases towards the reaction cell. These volumes may be increased considerably if applications require it, making use of presses that have larger loading force capability, larger frames and using larger anvils.

  8. Room temperature excitation spectroscopy of single quantum dots

    Directory of Open Access Journals (Sweden)

    Christian Blum

    2011-08-01

    Full Text Available We report a single molecule detection scheme to investigate excitation spectra of single emitters at room temperature. We demonstrate the potential of single emitter photoluminescence excitation spectroscopy by recording excitation spectra of single CdSe nanocrystals over a wide spectral range of 100 nm. The spectra exhibit emission intermittency, characteristic of single emitters. We observe large variations in the spectra close to the band edge, which represent the individual heterogeneity of the observed quantum dots. We also find specific excitation wavelengths for which the single quantum dots analyzed show an increased propensity for a transition to a long-lived dark state. We expect that the additional capability of recording excitation spectra at room temperature from single emitters will enable insights into the photophysics of emitters that so far have remained inaccessible.

  9. The effect of temperature in high temperature SHPB test

    International Nuclear Information System (INIS)

    Park, Kyoung Joon; Yang, Hyun Mo; Min, Oak Key

    2001-01-01

    The split Hopkinson pressure bar has used for a high strain rate impact test. Also, it has been developed and modified for compression, shear, tension, elevated temperature and subzero tests. In this paper, SHPB compression tests have been performed with pure titanium at elevated temperatures. The range of temperature is from room temperature to 1000 deg. C with interval of 200 .deg. C. To raise temperature of the specimen, a radiant heater which is composed of a pair of ellipsoidal cavities and halogen lamps is developed at high temperature SHPB test. There are some difficulties in a high temperature test such as temperature gradient, lubrication and prevention of oxidation of specimen. The temperature gradient of specimen is affected by the variation of temperature. Barreling occurred at not properly lubricated specimen. Stress-strain relations of pure titanium have been obtained in the range of strain rate at 1900/sec∼2000/sec and temperature at 25 .deg. C∼1000 .deg. C

  10. Temperature uniformity mapping in a high pressure high temperature reactor using a temperature sensitive indicator

    NARCIS (Netherlands)

    Grauwet, T.; Plancken, van der I.; Vervoort, L.; Matser, A.M.; Hendrickx, M.; Loey, van A.

    2011-01-01

    Recently, the first prototype ovomucoid-based pressure–temperature–time indicator (pTTI) for high pressure high temperature (HPHT) processing was described. However, for temperature uniformity mapping of high pressure (HP) vessels under HPHT sterilization conditions, this prototype needs to be

  11. Confinement of high temperature plasmas

    International Nuclear Information System (INIS)

    Bass, R.W.; Ferguson, H.R.; Fletcher, H.J.; Gardner, J.H.; Harrison, B.K.; Larsen, K.M.

    1980-01-01

    A high temperature plasma is confined in the shape of a topological torus by a topologically stable magnetic field which is everywhere constant on and tangent to the surface of the torus. There are exactly an even finite number of closed magnetic field lines on the plasma surface and all other magnetic field lines on the surface are asymptotic to the closed field lines. This magnetic field configuration is achieved by a set of current carrying conductors appropriately arranged with respect to the plasma and carrying suitably selected currents

  12. High-Temperature Test Technology

    Science.gov (United States)

    1987-03-01

    F33615-84-C-3213 Sc. ADDRESS (City. State and ZIP Code) 10. SOURCE OF: FUNDING NOBI . AFWVAL/FIBT PROGRAM PROJECT TASK WORK UNIT Wright-Patterson AFB OH...fly at speeds in excess of Mach 20. Aerodynamic heating "rom these hypersonic speeds will pro - duce vehicle surface temperatures as high as 3000*F. In...We believe that two former suppliers, Pyro-Metrics and lunar Infrared, are no longer in business. In addition, the Hi-Shear product line is now

  13. High-Performance Single Nanowire Tunnel Diodes

    DEFF Research Database (Denmark)

    Wallentin, Jesper; Persson, Johan Mikael; Wagner, Jakob Birkedal

    2010-01-01

    We demonstrate single nanowire tunnel diodes with room temperature peak current densities of up to 329 A/cm(2). Despite the large surface to volume ratio of the type-II InP-GaAs axial heterostructure nanowires, we measure peak to valley current ratios (PVCR) of up to 8.2 at room temperature and 27...

  14. Elasticity of fluorite at high temperatures

    Science.gov (United States)

    Eke, J.; Tennakoon, S.; Mookherjee, M.

    2017-12-01

    Fluorite (CaF2) is a simple halide with cubic space group symmetry (Fm-3m) and is often used as an internal pressure calibrant in moderate high-pressure/high-temperature experiments [1]. In order to gain insight into the elastic behavior of fluorite, we have conducted Resonant Ultrasound Spectroscopy (RUS) on a single crystal of fluorite with rectangular parallelepiped geometry. Using single crystal X-ray diffraction, we aligned the edges of the rectangular parallelepiped with [-1 1 1], [-1 1 -2], and [-1 -1 0] crystallographic directions. We conducted the RUS measurements up to 620 K. RUS spectra are influenced by the geometry, density, and the full elastic moduli tensor of the material. In our high-temperature RUS experiments, the geometry and density were constrained using thermal expansion from previous studies [2]. We determined the elasticity by minimizing the difference between observed resonance and calculated Eigen frequency using Rayleigh-Ritz method [3]. We found that at room temperature, the single crystal elastic moduli for fluorite are 170, 49, and 33 GPa for C11, C12, and C44 respectively. At room temperatures, the aggregate bulk modulus (K) is 90 GPa and the shear modulus (G) is 43 GPa. We note that the elastic moduli and sound wave velocities decrease linearly as a function of temperature with dVP /dT and dVS /dT being -9.6 ×10-4 and -5.0 ×10-4 km/s/K respectively. Our high-temperature RUS results are in good agreement with previous studies on fluorite using both Ultrasonic methods and Brillouin scattering [4,5]. Acknowledgement: This study is supported by US NSF awards EAR-1639552 and EAR-1634422. References: [1] Speziale, S., Duffy, T. S. 2002, Phys. Chem. Miner., 29, 465-472; [2] Roberts, R. B., White, G. K., 1986, J. Phys. C: Solid State Phys., 19, 7167-7172. [3] Migliori, A., Maynard, J. D., 2005, Rev. Sci. Instrum., 76, 121301. [4] Catlow, C. R. A., Comins, J. D., Germano, F. A., Harley, R. T., Hayes, W., 1978, J. Phys. C Solid State Phys

  15. Switching Characteristics and High-Temperature Dielectric Relaxation Behaviours of Pb(Zn1/3Nb2/3)0.91Ti0.09O₃ Single Crystal.

    Science.gov (United States)

    Zhu, Zhi; Tang, Xingui; Jiang, Yanping; Liu, Qiuxiang; Zhang, Tianfu; Li, Wenhua

    2017-03-28

    This work evaluated the resistance switching characteristics in the (100)-oriented Pb(Zn 1/3 Nb 2/3 ) 0.91 Ti 0.09 O₃ (PZNT) single crystal. The current hysteresis can be closely related to the ferroelectric polarization and we provided a possible explanation using a model about oxygen vacancies to analyze the mechanism of switching. The obvious frequency dispersion of the relative permittivity signified the relaxer-type behavior of the sample. The value of the relaxation parameter γ = 1.48 was estimated from the linear fit of the modified Curie-Weiss law, indicating the relaxer nature. High-temperature dielectric relaxation behaviors were revealed in the temperature region of 400-650 °C. In addition, under the measuring frequency of 10 kHz, ε r was tunable by changing the electric field and the largest tunability of ε r reached 14.78%. At room temperature, the high pyroelectric coefficient and detectivity figure of merit were reported.

  16. High-performance single nanowire tunnel diodes.

    Science.gov (United States)

    Wallentin, Jesper; Persson, Johan M; Wagner, Jakob B; Samuelson, Lars; Deppert, Knut; Borgström, Magnus T

    2010-03-10

    We demonstrate single nanowire tunnel diodes with room temperature peak current densities of up to 329 A/cm(2). Despite the large surface to volume ratio of the type-II InP-GaAs axial heterostructure nanowires, we measure peak to valley current ratios (PVCR) of up to 8.2 at room temperature and 27.6 at liquid helium temperature. These sub-100-nm-diameter structures are promising components for solar cells as well as electronic applications.

  17. Studies of high temperature superconductors

    International Nuclear Information System (INIS)

    Narlikar, A.

    1989-01-01

    The high temperature superconductors (HTSCs) discovered are from the family of ceramic oxides. Their large scale utilization in electrical utilities and in microelectronic devices are the frontal challenges which can perhaps be effectively met only through consolidated efforts and expertise of a multidisciplinary nature. During the last two years the growth of the new field has occurred on an international scale and perhaps has been more rapid than in most other fields. There has been an extraordinary rush of data and results which are continually being published as short texts dispersed in many excellent journals, some of which were started to ensure rapid publication exclusively in this field. As a result, the literature on HTSCs has indeed become so massive and so diffuse that it is becoming increasingly difficult to keep abreast with the important and reliable facets of this fast-growing field. This provided the motivation to evolve a process whereby both professional investigators and students can have ready access to up-to- date in-depth accounts of major technical advances happening in this field. The present series Studies of High Temperature Superconductors has been launched to, at least in part, fulfill this need

  18. Optical power limiting and transmitting properties of cadmium iodide single crystals: Temperature dependence

    Energy Technology Data Exchange (ETDEWEB)

    Miah, M. Idrish, E-mail: m.miah@griffith.edu.a [Nanoscale Science and Technology Centre, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)] [Biomolecular and Physical Sciences, Griffith University, Nathan, Brisbane, QLD 4111 (Australia)] [Department of Physics, University of Chittagong, Chittagong 4331 (Bangladesh)

    2009-09-14

    Optical limiting properties of the single crystals of cadmium iodide are investigated using ns laser pulses. It is found that the transmissions in the crystals increase with increasing temperature. However, they limit the transmissions at high input powers. The limiting power is found to be higher at higher temperature. From the measured transmission data, the photon absorption coefficients are estimated. The temperature dependence of the coefficients shows a decrease in magnitude with increasing temperature. This might be due to the temperature-dependent bandgap shift of the material. The results demonstrate that the cadmium iodide single crystals are promising materials for applications in optical power limiting devices.

  19. Optical power limiting and transmitting properties of cadmium iodide single crystals: Temperature dependence

    International Nuclear Information System (INIS)

    Miah, M. Idrish

    2009-01-01

    Optical limiting properties of the single crystals of cadmium iodide are investigated using ns laser pulses. It is found that the transmissions in the crystals increase with increasing temperature. However, they limit the transmissions at high input powers. The limiting power is found to be higher at higher temperature. From the measured transmission data, the photon absorption coefficients are estimated. The temperature dependence of the coefficients shows a decrease in magnitude with increasing temperature. This might be due to the temperature-dependent bandgap shift of the material. The results demonstrate that the cadmium iodide single crystals are promising materials for applications in optical power limiting devices.

  20. High Temperature Radio Frequency Loads

    CERN Document Server

    Federmann, S; Grudiev, A; Montesinos, E; Syratchev, I

    2011-01-01

    In the context of energy saving and recovery requirements the design of reliable and robust RF power loads which permit a high outlet temperature and high pressure of the cooling water is desirable. Cooling water arriving at the outlet withmore than 150 ◦C and high pressure has a higher value than water with 50 ◦C under low pressure. Conventional RF power loads containing dielectric and magnetic materials as well as sensitive ceramic windows usually do not permit going much higher than 90 ◦C. Here we present and discuss several design concepts for "metal only" RF high power loads. One concept is the application of magnetic steel corrugated waveguides near cutoff – this concept could find practical use above several GHz. Another solution are resonant structures made of steel to be installed in large waveguides for frequencies of 500 MHz or lower. Similar resonant structures above 100 MHz taking advantage of the rather high losses of normal steel may also be used in coaxial line geometries with large di...

  1. Study of single pulsed-field magnetization of Gd-Ba-Cu-O bulk high-temperature superconductor with a split type of armature coil for rotating machinery

    International Nuclear Information System (INIS)

    Morita, E; Matsuzaki, H; Kimura, Y; Ohtani, I; Ogata, H; Izumi, M; Nonaka, Y; Murakami, M; Ida, T; Sugimoto, H; Miki, M; Kitano, M

    2006-01-01

    We employed a Gd-bulk HTS as rotating field magnet poles aiming for a smaller and lighter axial-gap-type motor. The bulk was inserted in the split-type armature pulsed copper coils and cooled down to 77 K under zero field. Employing the bulk magnet to HTS rotating machinery, the number of pulsed field magnetizations should be reduced for practical use. Thereby, a single pulsed current was applied to the pulsed copper coils to magnetize the bulk. The trapped field distribution and transient flux behaviour strongly depend on the radial dimension of the armature coil with a vortex-type winding. On decreasing the diameter of the pulsed copper armature coil, the distribution of the trapped flux density on the surface of the bulk becomes close to a conical shape. In contrast to the use of a solenoid, the application of vortex-type armature coils to magnetization of Gd-bulk HTS shows a quick intervention of the external magnetic flux into the centre of the bulk. The magnetization to the bulk HTS of the vortex-type copper coils with an optimum radius is useful and may be an effective technique for applied bulk HTS for rotating machines such as motors and/or generators

  2. High Temperature Fiberoptic Thermal Imaging System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed Phase 1 program will fabricate and demonstrate a small diameter single fiber endoscope that can perform high temperature thermal imaging in a jet engine...

  3. Decomposition of the single-phase high-entropy alloy CrMnFeCoNi after prolonged anneals at intermediate temperatures

    Czech Academy of Sciences Publication Activity Database

    Otto, F.; Dlouhý, Antonín; Pradeep, K. G.; Kuběnová, Monika; Raabe, D.; Eggeler, G.; George, E. P.

    2016-01-01

    Roč. 112, JUN (2016), s. 40-52 ISSN 1359-6454 R&D Projects: GA ČR(CZ) GA14-22834S Institutional support: RVO:68081723 Keywords : High-entropy alloy * Phase stability * Solid solution * Aging * Phase transformations Subject RIV: JG - Metallurgy Impact factor: 5.301, year: 2016

  4. High concentration agglomerate dynamics at high temperatures.

    Science.gov (United States)

    Heine, M C; Pratsinis, S E

    2006-11-21

    The dynamics of agglomerate aerosols are investigated at high solids concentrations that are typical in industrial scale manufacture of fine particles (precursor mole fraction larger than 10 mol %). In particular, formation and growth of fumed silica at such concentrations by chemical reaction, coagulation, and sintering is simulated at nonisothermal conditions and compared to limited experimental data and commercial product specifications. Using recent chemical kinetics for silica formation by SiCl4 hydrolysis and neglecting aerosol polydispersity, the evolution of the diameter of primary particles (specific surface area, SSA), hard- and soft-agglomerates, along with agglomerate effective volume fraction (volume occupied by agglomerate) is investigated. Classic Smoluchowski theory is fundamentally limited for description of soft-agglomerate Brownian coagulation at high solids concentrations. In fact, these high concentrations affect little the primary particle diameter (or SSA) but dominate the soft-agglomerate diameter, structure, and volume fraction, leading to gelation consistent with experimental data. This indicates that restructuring and fragmentation should affect product particle characteristics during high-temperature synthesis of nanostructured particles at high concentrations in aerosol flow reactors.

  5. Temperature gradient-induced magnetization reversal of single ferromagnetic nanowires

    Science.gov (United States)

    Michel, Ann-Kathrin; Corinna Niemann, Anna; Boehnert, Tim; Martens, Stephan; Montero Moreno, Josep M.; Goerlitz, Detlef; Zierold, Robert; Reith, Heiko; Vega, Victor; Prida, Victor M.; Thomas, Andy; Gooth, Johannes; Nielsch, Kornelius

    2017-12-01

    In this study, we investigate the temperature- and temperature gradient-dependent magnetization reversal process of individual, single-domain Co39Ni61 and Fe15Ni85 ferromagnetic nanowires via the magneto-optical Kerr effect and magnetoresistance measurements. While the coercive fields (H C) and therefore the magnetic switching fields (H SW) generally decrease under isothermal conditions at elevated base temperatures (T base), temperature gradients (ΔT) along the nanowires lead to an increased switching field of up to 15% for ΔT  = 300 K in Co39Ni61 nanowires. This enhancement is attributed to a stress-induced, magneto-elastic anisotropy term due to an applied temperature gradient along the nanowire that counteracts the thermally assisted magnetization reversal process. Our results demonstrate that a careful distinction between locally elevated temperatures and temperature gradients has to be made in future heat-assisted magnetic recording devices.

  6. High Temperature Superconductor Accelerator Magnets

    CERN Document Server

    AUTHOR|(CDS)2079328; de Rijk, Gijs; Dhalle, Marc

    2016-11-10

    For future particle accelerators bending dipoles are considered with magnetic fields exceeding $20T$. This can only be achieved using high temperature superconductors (HTS). These exhibit different properties from classical low temperature superconductors and still require significant research and development before they can be applied in a practical accelerator magnet. In order to study HTS in detail, a five tesla demonstrator magnet named Feather-M2 is designed and constructed. The magnet is based on ReBCO coated conductor, which is assembled into a $10kA$ class Roebel cable. A new and optimized Aligned Block layout is used, which takes advantage of the anisotropy of the conductor. This is achieved by providing local alignment of the Roebel cable in the coil windings with the magnetic field lines. A new Network Model capable of analyzing transient electro-magnetic and thermal phenomena in coated conductor cables and coils is developed. This model is necessary to solve critical issues in coated conductor ac...

  7. The Effect of Elevated CO2 and Increased Temperature on in Vitro Fertilization Success and Initial Embryonic Development of Single Male:Female Crosses of Broad-Cast Spawning Corals at Mid- and High-Latitude Locations

    Directory of Open Access Journals (Sweden)

    Miriam Schutter

    2015-05-01

    Full Text Available The impact of global climate change on coral reefs is expected to be most profound at the sea surface, where fertilization and embryonic development of broadcast-spawning corals takes place. We examined the effect of increased temperature and elevated CO2 levels on the in vitro fertilization success and initial embryonic development of broadcast-spawning corals using a single male:female cross of three different species from mid- and high-latitude locations: Lyudao, Taiwan (22° N and Kochi, Japan (32° N. Eggs were fertilized under ambient conditions (27 °C and 500 μatm CO2 and under conditions predicted for 2100 (IPCC worst case scenario, 31 °C and 1000 μatm CO2. Fertilization success, abnormal development and early developmental success were determined for each sample. Increased temperature had a more profound influence than elevated CO2. In most cases, near-future warming caused a significant drop in early developmental success as a result of decreased fertilization success and/or increased abnormal development. The embryonic development of the male:female cross of A. hyacinthus from the high-latitude location was more sensitive to the increased temperature (+4 °C than the male:female cross of A. hyacinthus from the mid-latitude location. The response to the elevated CO2 level was small and highly variable, ranging from positive to negative responses. These results suggest that global warming is a more significant and universal stressor than ocean acidification on the early embryonic development of corals from mid- and high-latitude locations.

  8. High temperature industrial heat pumps

    Energy Technology Data Exchange (ETDEWEB)

    Berghmans, J. (Louvain Univ., Heverlee (Belgium). Inst. Mechanica)

    1990-01-01

    The present report intends to describe the state of the art of high temperature industrial heat pumps. A description is given of present systems on the market. In addition the research and development efforts on this subject are described. Compression (open as well as closed cycle) systems, as well as absorption heat pumps (including transformers), are considered. This state of the art description is based upon literature studies performed by a team of researchers from the Katholieke Universiteit Leuven, Belgium. The research team also analysed the economics of heat pumps of different types under the present economic conditions. The heat pumps are compared with conventional heating systems. This analysis was performed in order to evaluate the present condition of the heat pump in the European industry.

  9. Faraday imaging at high temperatures

    Science.gov (United States)

    Hackel, Lloyd A.; Reichert, Patrick

    1997-01-01

    A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid.

  10. Faraday imaging at high temperatures

    International Nuclear Information System (INIS)

    Hackel, L.A.; Reichert, P.

    1997-01-01

    A Faraday filter rejects background light from self-luminous thermal objects, but transmits laser light at the passband wavelength, thus providing an ultra-narrow optical bandpass filter. The filter preserves images so a camera looking through a Faraday filter at a hot target illuminated by a laser will not see the thermal radiation but will see the laser radiation. Faraday filters are useful for monitoring or inspecting the uranium separator chamber in an atomic vapor laser isotope separation process. Other uses include viewing welds, furnaces, plasma jets, combustion chambers, and other high temperature objects. These filters are can be produced at many discrete wavelengths. A Faraday filter consists of a pair of crossed polarizers on either side of a heated vapor cell mounted inside a solenoid. 3 figs

  11. Influence of cobalt, tantaum and tungsten on the high temperature mechanical properties of single crystal nickel-base superalloys. Ph.D. Thesis - Case Western Reserve Univ.

    Science.gov (United States)

    Nathal, M. V.

    1984-01-01

    For alloys with the baseline refractory metal level of 3 percent Ta and 10 percent W, decreases in Co level from 10 to 0 percent resulted in increased tensile strength and creep resistance. Substitution of W for Ta resulted in decreased creep life at high stresses but improved life at low stresses. Substitution of Ni for Ta caused large reductions in tensile strength and creep resistance, and corresponding increases in ductility. For these alloys with low Ta plus W totals, strength was independent of Co level. The increases in tensile strength with increases in refractory metal content were related to the increases in gamma volume fraction and solid solution hardening. Increases in strength as Co level decreased were considered to be the result of coherency strain hardening from the increased lattice mismatch. Dislocation shear through the gamma-gamma interface is considered to be the rate limiting step in the deformation process.

  12. High temperature control rod assembly

    Science.gov (United States)

    Vollman, Russell E.

    1991-01-01

    A high temperature nuclear control rod assembly comprises a plurality of substantially cylindrical segments flexibly joined together in succession by ball joints. The segments are made of a high temperature graphite or carbon-carbon composite. The segment includes a hollow cylindrical sleeve which has an opening for receiving neutron-absorbing material in the form of pellets or compacted rings. The sleeve has a threaded sleeve bore and outer threaded surface. A cylindrical support post has a threaded shaft at one end which is threadably engaged with the sleeve bore to rigidly couple the support post to the sleeve. The other end of the post is formed with a ball portion. A hollow cylindrical collar has an inner threaded surface engageable with the outer threaded surface of the sleeve to rigidly couple the collar to the sleeve. the collar also has a socket portion which cooperates with the ball portion to flexibly connect segments together to form a ball and socket-type joint. In another embodiment, the segment comprises a support member which has a threaded shaft portion and a ball surface portion. The threaded shaft portion is engageable with an inner threaded surface of a ring for rigidly coupling the support member to the ring. The ring in turn has an outer surface at one end which is threadably engageably with a hollow cylindrical sleeve. The other end of the sleeve is formed with a socket portion for engagement with a ball portion of the support member. In yet another embodiment, a secondary rod is slidably inserted in a hollow channel through the center of the segment to provide additional strength. A method for controlling a nuclear reactor utilizing the control rod assembly is also included.

  13. FY16 ASME High Temperature Code Activities

    Energy Technology Data Exchange (ETDEWEB)

    Swindeman, M. J. [Chromtech Inc., Oak Ridge, TN (United States); Jetter, R. I. [R. I Jetter Consulting, Pebble Beach, CA (United States); Sham, T. -L. [Argonne National Lab. (ANL), Argonne, IL (United States)

    2016-09-01

    One of the objectives of the ASME high temperature Code activities is to develop and validate both improvements and the basic features of Section III, Division 5, Subsection HB, Subpart B (HBB). The overall scope of this task is to develop a computer program to be used to assess whether or not a specific component under specified loading conditions will satisfy the elevated temperature design requirements for Class A components in Section III, Division 5, Subsection HB, Subpart B (HBB). There are many features and alternative paths of varying complexity in HBB. The initial focus of this task is a basic path through the various options for a single reference material, 316H stainless steel. However, the program will be structured for eventual incorporation all the features and permitted materials of HBB. Since this task has recently been initiated, this report focuses on the description of the initial path forward and an overall description of the approach to computer program development.

  14. Multifunctional, High-Temperature Nanocomposites

    Science.gov (United States)

    Connell, John W.; Smith, Joseph G.; Siochi, Emilie J.; Working, Dennis C.; Criss, Jim M.; Watson, Kent A.; Delozier, Donavon M.; Ghose, Sayata

    2007-01-01

    In experiments conducted as part of a continuing effort to incorporate multifunctionality into advanced composite materials, blends of multi-walled carbon nanotubes and a resin denoted gPETI-330 h (wherein gPETI h is an abbreviation for gphenylethynyl-terminated imide h) were prepared, characterized, and fabricated into moldings. PETI-330 was selected as the matrix resin in these experiments because of its low melt viscosity (2 hours at 280 C), and high temperature performance (>1,000 hours at 288 C). The multi-walled carbon nanotubes (MWCNTs), obtained from the University of Kentucky, were selected because of their electrical and thermal conductivity and their small diameters. The purpose of these experiments was to determine the combination of thermal, electrical, and mechanical properties achievable while still maintaining melt processability. The PETI-330/MWCNT mixtures were prepared at concentrations ranging from 3 to 25 weight-percent of MWCNTs by dry mixing of the constituents in a ball mill using zirconia beads. The resulting powders were characterized for degree of mixing and thermal and rheological properties. The neat resin was found to have melt viscosity between 5 and 10 poise. At 280 C and a fixed strain rate, the viscosity was found to increase with time. At this temperature, the phenylethynyl groups do not readily react and so no significant curing of the resin occurred. For MWCNT-filled samples, melt viscosity was reasonably steady at 280 C and was greater in samples containing greater proportions of MWCNTs. The melt viscosity for 20 weightpercent of MWCNTs was found to be .28,000 poise, which is lower than the initial estimated allowable maximum value of 60,000 poise for injection molding. Hence, MWCNT loadings of as much as 20 percent were deemed to be suitable compositions for scale-up. High-resolution scanning electron microscopy (HRSEM) showed the MWCNTs to be well dispersed in the polymer matrices, while high-resolution transmission electron

  15. High temperature autoclave vacuum seals

    Science.gov (United States)

    Hoffman, J. R.; Simpson, W. G.; Walker, H. M.

    1971-01-01

    Aluminum sheet forms effective sealing film at temperatures up to 728 K. Soft aluminum wire rings provide positive seal between foil and platen. For applications at temperatures above aluminum's service temperature, stainless steel is used as film material and copper wire as sealant.

  16. High temperature incineration. Densification of granules from high temperature incineration

    International Nuclear Information System (INIS)

    Voorde, N. van de; Claes, J.; Taeymans, A.; Hennart, D.; Gijbels, J.; Balleux, W.; Geenen, G.; Vangeel, J.

    1982-01-01

    The incineration system of radioactive waste discussed in this report, is an ''integral'' system, which directly transforms a definite mixture of burnable and unburnable radioactive waste in a final product with a sufficient insolubility to be safely disposed of. At the same time, a significant volume reduction occurs by this treatment. The essential part of the system is a high temperature incinerator. The construction of this oven started in 1974, and while different tests with simulated inactive or very low-level active waste were carried out, the whole system was progressively and continuously extended and adapted, ending finally in an installation with completely remote control, enclosed in an alpha-tight room. In this report, a whole description of the plant and of its auxiliary installations will be given; then the already gained experimental results will be summarized. Finally, the planning for industrial operation will be briefly outlined. An extended test with radioactive waste, which was carried out in March 1981, will be discussed in the appendix

  17. Vega Subsea Development - a high pressure et high temperature challenge

    Energy Technology Data Exchange (ETDEWEB)

    Erlandsen, Jostein

    2010-07-01

    The Vega subsea field, tied back to the Gjoea platform with a 51 kilometre single pipeline is one of the most challenging technology projects undertaken by Statoil. It is the combination of extremes rather than one record breaking achievement that set the Vega development apart. Production temperatures from -30 C to +135 C and flowing wellhead pressure up to 475 bars combined with high wax appearance temperature and low start-up temperatures expose Vega to both wax deposition and hydrates. New subsea metering systems have been developed due to coming led production from two licenses and two independent subsea MEG injection systems implemented. The paper will focus on the qualification process of barrier elements and the potential challenges related to qualification of complex production and safety critical systems such as the subsea production control system and the subsea instrumented pipeline pressure protection system (SIPPS). (Author)

  18. High Temperature Solid Lubricant Coating for High Temperature Wear Applications

    Science.gov (United States)

    DellaCorte, Christopher (Inventor); Edmonds, Brian J (Inventor)

    2014-01-01

    A self-lubricating, friction and wear reducing composite useful over a wide temperature range is described herein. The composite includes metal bonded chromium oxide dispersed in a metal binder having a substantial amount of nickel. The composite contains a fluoride of at least one Group I, Group II, or rare earth metal, and optionally a low temperature lubricant metal.

  19. Mechanical behavior of high strength ceramic fibers at high temperatures

    Science.gov (United States)

    Tressler, R. E.; Pysher, D. J.

    1991-01-01

    The mechanical behavior of commercially available and developmental ceramic fibers, both oxide and nonoxide, has been experimentally studied at expected use temperatures. In addition, these properties have been compared to results from the literature. Tensile strengths were measured for three SiC-based and three oxide ceramic fibers for temperatures from 25 C to 1400 C. The SiC-based fibers were stronger but less stiff than the oxide fibers at room temperature and retained more of both strength and stiffness to high temperatures. Extensive creep and creep-rupture experiments have been performed on those fibers from this group which had the best strengths above 1200 C in both single filament tests and tests of fiber bundles. The creep rates for the oxides are on the order of two orders of magnitude faster than the polymer derived nonoxide fibers. The most creep resistant filaments available are single crystal c-axis sapphire filaments. Large diameter CVD fabricated SiC fibers are the most creep and rupture resistant nonoxide polycrystalline fibers tested to date.

  20. High-temperature thermocouples and related methods

    Science.gov (United States)

    Rempe, Joy L [Idaho Falls, ID; Knudson, Darrell L [Firth, ID; Condie, Keith G [Idaho Falls, ID; Wilkins, S Curt [Idaho Falls, ID

    2011-01-18

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

  1. Electrochemical high-temperature gas sensors

    Science.gov (United States)

    Saruhan, B.; Stranzenbach, M.; Yüce, A.; Gönüllü, Y.

    2012-06-01

    Combustion produced common air pollutant, NOx associates with greenhouse effects. Its high temperature detection is essential for protection of nature. Component-integration capable high-temperature sensors enable the control of combustion products. The requirements are quantitative detection of total NOx and high selectivity at temperatures above 500°C. This study reports various approaches to detect NO and NO2 selectively under lean and humid conditions at temperatures from 300°C to 800°C. All tested electrochemical sensors were fabricated in planar design to enable componentintegration. We suggest first an impedance-metric gas sensor for total NOx-detection consisting of NiO- or NiCr2O4-SE and PYSZ-electrolyte. The electrolyte-layer is about 200μm thickness and constructed of quasi-single crystalline columns. The sensing-electrode (SE) is magnetron sputtered thin-layers of NiO or NiCr2O4. Sensor sensitivity for detection of total NOx has been measured by applying impedance analysis. The cross-sensitivity to other emission gases such as CO, CO2, CH4 and oxygen (5 vol.%) has been determined under 0-1000ppm NO. Sensor maintains its high sensitivity at temperatures up to 550°C and 600°C, depending on the sensing-electrode. NiO-SE yields better selectivity to NO in the presence of oxygen and have shorter response times comparing to NiCr2O4-SE. For higher temperature NO2-sensing capability, a resistive DC-sensor having Al-doped TiO2-sensing layers has been employed. Sensor-sensitivity towards NO2 and cross-sensitivity to CO has been determined in the presence of H2O at temperatures 600°C and 800°C. NO2 concentrations varying from 25 to 100ppm and CO concentrations from 25 to 75ppm can be detected. By nano-tubular structuring of TiO2, NO2 sensitivity of the sensor was increased.

  2. High Temperature Superconducting Underground Cable

    International Nuclear Information System (INIS)

    Farrell, Roger A.

    2010-01-01

    The purpose of this Project was to design, build, install and demonstrate the technical feasibility of an underground high temperature superconducting (HTS) power cable installed between two utility substations. In the first phase two HTS cables, 320 m and 30 m in length, were constructed using 1st generation BSCCO wire. The two 34.5 kV, 800 Arms, 48 MVA sections were connected together using a superconducting joint in an underground vault. In the second phase the 30 m BSCCO cable was replaced by one constructed with 2nd generation YBCO wire. 2nd generation wire is needed for commercialization because of inherent cost and performance benefits. Primary objectives of the Project were to build and operate an HTS cable system which demonstrates significant progress towards commercial progress and addresses real world utility concerns such as installation, maintenance, reliability and compatibility with the existing grid. Four key technical areas addressed were the HTS cable and terminations (where the cable connects to the grid), cryogenic refrigeration system, underground cable-to-cable joint (needed for replacement of cable sections) and cost-effective 2nd generation HTS wire. This was the worlds first installation and operation of an HTS cable underground, between two utility substations as well as the first to demonstrate a cable-to-cable joint, remote monitoring system and 2nd generation HTS.

  3. High Temperature Superconducting Underground Cable

    Energy Technology Data Exchange (ETDEWEB)

    Farrell, Roger, A.

    2010-02-28

    The purpose of this Project was to design, build, install and demonstrate the technical feasibility of an underground high temperature superconducting (HTS) power cable installed between two utility substations. In the first phase two HTS cables, 320 m and 30 m in length, were constructed using 1st generation BSCCO wire. The two 34.5 kV, 800 Arms, 48 MVA sections were connected together using a superconducting joint in an underground vault. In the second phase the 30 m BSCCO cable was replaced by one constructed with 2nd generation YBCO wire. 2nd generation wire is needed for commercialization because of inherent cost and performance benefits. Primary objectives of the Project were to build and operate an HTS cable system which demonstrates significant progress towards commercial progress and addresses real world utility concerns such as installation, maintenance, reliability and compatibility with the existing grid. Four key technical areas addressed were the HTS cable and terminations (where the cable connects to the grid), cryogenic refrigeration system, underground cable-to-cable joint (needed for replacement of cable sections) and cost-effective 2nd generation HTS wire. This was the world’s first installation and operation of an HTS cable underground, between two utility substations as well as the first to demonstrate a cable-to-cable joint, remote monitoring system and 2nd generation HTS.

  4. (Krauss) at constant high temperatures

    African Journals Online (AJOL)

    the various physical and chemical factors that may affect freshwater snails. However, it is generally accepted that temperature is one of the most important enviromental factors which can, amongst others, determine the geo- graphical distribution of organisms (Stuckenberg 1969). In order to assess the effect of temperature ...

  5. High Temperature Chemistry at NASA: Hot Topics

    Science.gov (United States)

    Jacobson, Nathan S.

    2014-01-01

    High Temperature issues in aircraft engines Hot section: Ni and Co based Superalloys Oxidation and Corrosion (Durability) at high temperatures. Thermal protection system (TPS) and RCC (Reinforced Carbon-Carbon) on the Space Shuttle Orbiter. High temperatures in other worlds: Planets close to their stars.

  6. High temperature vapors science and technology

    CERN Document Server

    Hastie, John

    2012-01-01

    High Temperature Vapors: Science and Technology focuses on the relationship of the basic science of high-temperature vapors to some areas of discernible practical importance in modern science and technology. The major high-temperature problem areas selected for discussion include chemical vapor transport and deposition; the vapor phase aspects of corrosion, combustion, and energy systems; and extraterrestrial high-temperature species. This book is comprised of seven chapters and begins with an introduction to the nature of the high-temperature vapor state, the scope and literature of high-temp

  7. Some Debye temperatures from single-crystal elastic constant data

    Science.gov (United States)

    Robie, R.A.; Edwards, J.L.

    1966-01-01

    The mean velocity of sound has been calculated for 14 crystalline solids by using the best recent values of their single-crystal elastic stiffness constants. These mean sound velocities have been used to obtain the elastic Debye temperatures ??De for these materials. Models of the three wave velocity surfaces for calcite are illustrated. ?? 1966 The American Institute of Physics.

  8. High Field Magnetization of Tb Single Crystals

    DEFF Research Database (Denmark)

    Roeland, L. W.; Cock, G. J.; Lindgård, Per-Anker

    1975-01-01

    The magnetization of Tb single crystals was measured in magnetic fields to 34T along the hard direction at temperature of 1.8, 4.2, 65.5 and 77K, and along with easy direction at 4.2 and 77K. The data are compared with the results of a self-consistent spin wave calculation using a phenomenological...

  9. Energy and temperature fluctuations in the single electron box

    International Nuclear Information System (INIS)

    Berg, Tineke L van den; Brange, Fredrik; Samuelsson, Peter

    2015-01-01

    In mesoscopic and nanoscale systems at low temperatures, charge carriers are typically not in thermal equilibrium with the surrounding lattice. The resulting, non-equilibrium dynamics of electrons has only begun to be explored. Experimentally the time-dependence of the electron temperature (deviating from the lattice temperature) has been investigated in small metallic islands. Motivated by these experiments, we investigate theoretically the electronic energy and temperature fluctuations in a metallic island in the Coulomb blockade regime, tunnel coupled to an electronic reservoir, i.e. a single electron box. We show that electronic quantum tunnelling between the island and the reservoir, in the absence of any net charge or energy transport, induces fluctuations of the island electron temperature. The full distribution of the energy transfer as well as the island temperature is derived within the framework of full counting statistics. In particular, the low-frequency temperature fluctuations are analysed, fully accounting for charging effects and non-zero reservoir temperature. The experimental requirements for measuring the predicted temperature fluctuations are discussed. (paper)

  10. High temperature turbine engine structure

    Energy Technology Data Exchange (ETDEWEB)

    Carruthers, W.D.; Boyd, G.L.

    1993-07-20

    A hybrid ceramic/metallic gas turbine is described comprising; a housing defining an inlet, an outlet, and a flow path communicating the inlet with the outlet for conveying a flow of fluid through the housing, a rotor member journaled by the housing in the flow path, the rotor member including a compressor rotor portion rotatively inducting ambient air via the inlet and delivering this air pressurized to the flow path downstream of the compressor rotor, a combustor disposed in the flow path downstream of the compressor receiving the pressurized air along with a supply of fuel to maintain combustion providing a flow of high temperature pressurized combustion products in the flow path downstream thereof, the rotor member including a turbine rotor portion disposed in the flow path downstream of the combustor and rotatively expanding the combustion products toward ambient for flow from the turbine engine via the outlet, the turbine rotor portion providing shaft power driving the compressor rotor portion and an output shaft portion of the rotor member, a disk-like metallic housing portion journaling the rotor member to define a rotational axis therefore, and a disk-like annular ceramic turbine shroud member bounding the flow path downstream of the combustor and circumscribing the turbine rotor portion to define a running clearance therewith, the disk-like ceramic turbine shroud member having a reference axis coaxial with the rotational axis and being spaced axially from the metallic housing portion in mutually parallel concentric relation therewith and a plurality of spacers disposed between ceramic disk-like shroud member and the metallic disk-like housing portion and circumferentially spaced apart, each of the spacers having a first and second end portion having an end surface adjacent the shroud member and the housing portion respectively, the end surfaces having a cylindrical curvature extending transversely relative to the shroud member and the housing portion.

  11. Magnetic Ordering in Layered High Temperature Superconductors

    OpenAIRE

    Sergeeva, G. G.

    1999-01-01

    We discuss the scenario of two-step magnetic ordering in layered high temperature superconductors after charge ordering. As the temperature decreases, the transition from 3D Heisenberg spin behavior to 2D XY coupling of the Cu spins occurs at Berezinskii-Kosterlitz-Thouless temperature in dielectric stripes. Further temperature decreasing leads to the 3D spin glass transition.

  12. Thermoelastic properties of minerals at high temperature

    Indian Academy of Sciences (India)

    obtained when δT is temperature-dependent are in close agreement with experimental data. ... temperature-independent and then by taking δT as temperature-dependent. 2. Method of analysis. The anharmonicity of the lattice vibration is generally due to thermal ... At high temperature, to understand the elastic behaviour.

  13. DURIP95/Ultra High Precision Diagnostic High Temperature Laboratory

    National Research Council Canada - National Science Library

    Newaz, Golam M

    1997-01-01

    The DURIP grant was used to develop an efficient high temperature laboratory with high precision instruments to make deformation and load measurements in high temperature materials including advanced composites...

  14. High temperature superconducting fault current limiter

    Science.gov (United States)

    Hull, John R.

    1997-01-01

    A fault current limiter (10) for an electrical circuit (14). The fault current limiter (10) includes a high temperature superconductor (12) in the electrical circuit (14). The high temperature superconductor (12) is cooled below its critical temperature to maintain the superconducting electrical properties during operation as the fault current limiter (10).

  15. Thermodynamics of High Temperature Plasmas

    Directory of Open Access Journals (Sweden)

    Ettore Minardi

    2009-03-01

    Full Text Available In this work we discuss how and to what extent the thermodynamic concepts and the thermodynamic formalism can be extended to the description of high temperature states of the plasma not necessarily associated with a Boltzmann distribution and with thermal equilibrium.The discussion is based on the “magnetic or electrostatic entropy concept”, an interpretative and predictive tool based on probability and information, defined in a suitably coarse-grained possibility space of all current density or of all electric charge density distributions under testable constraints, and whose variation properties are proven to be related under certain conditions to the equilibrium and the stability of the system. In the case of magnetic equilibrium the potentiality of the magnetic entropy concept is illustrated by comparing the predictions of the current density and pressure profiles with the observations in different tokamak machines and different tokamak regimes, as well as by showing how the equilibrium and the stability in devices as different as the reversed field pinch or the magnetic well are described by the variation properties of the same entropy functional applied to the different situations. In fact it emerges that the maximum of the entropy can be seen in these different cases as an optimization constraint for the minimum of the magnetic energy. The application of the entropy concept to the electrostatic processes shows in particular that the so-called reactive instabilities (non-dissipative, non-resonant instabilities with a marginal point admit a neighboring state with higher entropy and are therefore of special relevance from the point of view of the physical evolution of the system. In this case the thermodynamic formalism allows the introduction of the concept of “thermodynamic fluctuations” of the macroscopic charge density and provides a method for the calculation of the “thermodynamic” fluctuation levels both on the stable as

  16. Resonance integral calculations for high temperature reactors

    International Nuclear Information System (INIS)

    Blake, J.P.H.

    1960-02-01

    Methods of calculation of resonance integrals of finite dilution and temperature are given for both, homogeneous and heterogeneous geometries, together with results obtained from these methods as applied to the design of high temperature reactors. (author)

  17. Hot nuclei: high temperatures, high angular momenta

    International Nuclear Information System (INIS)

    Guerreau, D.

    1991-01-01

    A review is made of the present status concerning the production of hot nuclei above 5 MeV temperature, concentrating mainly on the possible experimental evidences for the attainment of a critical temperature, on the existence of dynamical limitations to the energy deposition and on the experimental signatures for the formation of hot spinning nuclei. The data strongly suggest a nuclear disassembly in collisions involving very heavy ions at moderate incident velocities. Furthermore, hot nuclei seem to be quite stable against rotation on a short time scale. (author) 26 refs.; 12 figs

  18. Deep Trek High Temperature Electronics Project

    Energy Technology Data Exchange (ETDEWEB)

    Bruce Ohme

    2007-07-31

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

  19. High temperature and pressure electrochemical test station

    Science.gov (United States)

    Chatzichristodoulou, C.; Allebrod, F.; Mogensen, M.

    2013-05-01

    An electrochemical test station capable of operating at pressures up to 100 bars and temperatures up to 400 °C has been established. It enables control of the partial pressures and mass flow of O2, N2, H2, CO2, and H2O in a single or dual environment arrangement, measurements with highly corrosive media, as well as localized sampling of gas evolved at the electrodes for gas analysis. A number of safety and engineering design challenges have been addressed. Furthermore, we present a series of electrochemical cell holders that have been constructed in order to accommodate different types of cells and facilitate different types of electrochemical measurements. Selected examples of materials and electrochemical cells examined in the test station are provided, ranging from the evaluation of the ionic conductivity of liquid electrolytic solutions immobilized in mesoporous ceramic structures, to the electrochemical characterization of high temperature and pressure alkaline electrolysis cells and the use of pseudo-reference electrodes for the separation of each electrode contribution. A future perspective of various electrochemical processes and devices that can be developed with the use of the established test station is provided.

  20. Single-photon-level quantum memory at room temperature.

    Science.gov (United States)

    Reim, K F; Michelberger, P; Lee, K C; Nunn, J; Langford, N K; Walmsley, I A

    2011-07-29

    Room-temperature, easy-to-operate quantum memories are essential building blocks for future long distance quantum information networks operating on an intercontinental scale, because devices like quantum repeaters, based on quantum memories, will have to be deployed in potentially remote, inaccessible locations. Here we demonstrate controllable, broadband and efficient storage and retrieval of weak coherent light pulses at the single-photon level in warm atomic cesium vapor using the robust far off-resonant Raman memory scheme. We show that the unconditional noise floor of this technically simple quantum memory is low enough to operate in the quantum regime, even in a room-temperature environment.

  1. High temperature alloys and ceramic heat exchanger

    International Nuclear Information System (INIS)

    Okamoto, Masaharu

    1984-04-01

    From the standpoint of energy saving, the future operating temperatures of process heat and gas turbine plants will become higher. For this purpose, ceramics is the most promissing candidate material in strength for application to high-temperature heat exchangers. This report deals with a servey of characteristics of several high-temperature metallic materials and ceramics as temperature-resistant materials; including a servey of the state-of-the-art of ceramic heat exchanger technologies developed outside of Japan, and a study of their application to the intermediate heat exchanger of VHTR (a very-high-temperature gas-cooled reactor). (author)

  2. High temperature durable catalyst development

    Science.gov (United States)

    Snow, G. C.; Tong, H.

    1981-01-01

    A program has been carried out to develop a catalytic reactor capable of operation in environments representative of those anticipated for advanced automotive gas turbine engines. A reactor consisting of a graded cell honeycomb support with a combination of noble metal and metal oxide catalyst coatings was built and successfully operated for 1000 hr. At an air preheat temperature of 740 K and a propane/air ratio of 0.028 by mass, the adiabatic flame temperature was held at about 1700 K. The graded cell monolithic reaction measured 5 cm in diameter by 10.2 cm in length and was operated at a reference velocity of 14.0 m/s at 1 atm. Measured NOx levels remained below 5 ppm, while unburned hydrocarbon concentrations registered near zero and carbon monoxide levels were nominally below 20 ppm.

  3. Temperature dependence of magnetoresistance in copper single crystals

    Science.gov (United States)

    Bian, Q.; Niewczas, M.

    2018-03-01

    Transverse magnetoresistance of copper single crystals has been measured in the orientation of open-orbit from 2 K to 20 K for fields up to 9 T. The experimental Kohler's plots display deviation between individual curves below 16 K and overlap in the range of 16 K-20 K. The violation of the Kohler's rule below 16 K indicates that the magnetotransport can not be described by the classical theory of electron transport on spherical Fermi surface with a single relaxation time. A theoretical model incorporating two energy bands, spherical and cylindrical, with different relaxation times has been developed to describe the magnetoresistance data. The calculations show that the electron-phonon scattering rates at belly and neck regions of the Fermi surface have different temperature dependencies, and in general, they do not follow T3 law. The ratio of the relaxation times in belly and neck regions decreases parabolically with temperature as A - CT2 , with A and C being constants.

  4. Dynamic Model of High Temperature PEM Fuel Cell Stack Temperature

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen

    2007-01-01

    The present work involves the development of a model for predicting the dynamic temperature of a high temperature PEM (HTPEM) fuel cell stack. The model is developed to test different thermal control strategies before implementing them in the actual system. The test system consists of a prototype...... parts, where also the temperatures are measured. The heat balance of the system involves a fuel cell model to describe the heat added by the fuel cells when a current is drawn. Furthermore the model also predicts the temperatures, when heating the stack with external heating elements for start-up, heat...... the stack at a high stoichiometric air flow. This is possible because of the PBI fuel cell membranes used, and the very low pressure drop in the stack. The model consists of a discrete thermal model dividing the stack into three parts: inlet, middle and end and predicting the temperatures in these three...

  5. Single-atom reversible recording at room temperature

    DEFF Research Database (Denmark)

    Quaade, Ulrich; Stokbro, Kurt; Lin, Rong

    2001-01-01

    A single hydrogen atom can be reversibly switched between two symmetric sites on a silicon dimer at the surface of Si(100) using a scanning tunnelling microscope (STM). This is a model binary switch for silicon-based atom-scale reversible data storage at room temperature. In this paper we...... investigate two important aspects of using this single-atom switch as a memory device. First, the switching is electron stimulated, and through detailed modelling the switching probability per electron is accurately deduced. Second, we have investigated the possibilities for desorbing single hydrogen atoms...... to construct ordered arrays of switches to manufacture a memory device. Two desorption mechanisms have been considered: the well known electron-induced desorption at negative sample bias and a novel mechanism probably involving elastic deformation of the tip. For both mechanisms mechanical stability of the STM...

  6. Single interval Rényi entropy at low temperature

    Science.gov (United States)

    Chen, Bin; Wu, Jie-qiang

    2014-08-01

    In this paper, we calculate the Rényi entropy of one single interval on a circle at finite temperature in 2D CFT. In the low temperature limit, we expand the thermal density matrix level by level in the vacuum Verma module, and calculate the first few leading terms in e -π/ T L explicitly. On the other hand, we compute the same Rényi entropy holographically. After considering the dependence of the Rényi entropy on the temperature, we manage to fix the interval-independent constant terms in the classical part of holographic Rényi entropy. We furthermore extend the analysis in [9] to higher orders and find exact agreement between the results from field theory and bulk computations in the large central charge limit. Our work provides another piece of evidence to support holographic computation of Rényi entropy in AdS3/CFT2 correspondence, even with thermal effect.

  7. High Temperature Capacitors for Venus Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this SBIR program, TRS Technologies has developed several new dielectrics for high temperature applications including signal conditioning, filtering and energy...

  8. High Temperature Superconducting Inductor for Antenna Matching

    National Research Council Canada - National Science Library

    Cadotte, R

    1998-01-01

    .... Towards this goal, the U.S. Army Research Laboratory is developing a high critical temperature superconducting spiral inductor and cryogenically cooled amplifier to demonstrate increased sensitivity...

  9. High temperature phase equilibria and phase diagrams

    CERN Document Server

    Kuo, Chu-Kun; Yan, Dong-Sheng

    2013-01-01

    High temperature phase equilibria studies play an increasingly important role in materials science and engineering. It is especially significant in the research into the properties of the material and the ways in which they can be improved. This is achieved by observing equilibrium and by examining the phase relationships at high temperature. The study of high temperature phase diagrams of nonmetallic systems began in the early 1900s when silica and mineral systems containing silica were focussed upon. Since then technical ceramics emerged and more emphasis has been placed on high temperature

  10. Advances in high temperature chemistry 1

    CERN Document Server

    Eyring, Leroy

    2013-01-01

    Advances in High Temperature Chemistry, Volume 1 describes the complexities and special and changing characteristics of high temperature chemistry. After providing a brief definition of high temperature chemistry, this nine-chapter book goes on describing the experiments and calculations of diatomic transition metal molecules, as well as the advances in applied wave mechanics that may contribute to an understanding of the bonding, structure, and spectra of the molecules of high temperature interest. The next chapter provides a summary of gaseous ternary compounds of the alkali metals used in

  11. Investigations into High Temperature Components and Packaging

    Energy Technology Data Exchange (ETDEWEB)

    Marlino, L.D.; Seiber, L.E.; Scudiere, M.B.; M.S. Chinthavali, M.S.; McCluskey, F.P.

    2007-12-31

    The purpose of this report is to document the work that was performed at the Oak Ridge National Laboratory (ORNL) in support of the development of high temperature power electronics and components with monies remaining from the Semikron High Temperature Inverter Project managed by the National Energy Technology Laboratory (NETL). High temperature electronic components are needed to allow inverters to operate in more extreme operating conditions as required in advanced traction drive applications. The trend to try to eliminate secondary cooling loops and utilize the internal combustion (IC) cooling system, which operates with approximately 105 C water/ethylene glycol coolant at the output of the radiator, is necessary to further reduce vehicle costs and weight. The activity documented in this report includes development and testing of high temperature components, activities in support of high temperature testing, an assessment of several component packaging methods, and how elevated operating temperatures would impact their reliability. This report is organized with testing of new high temperature capacitors in Section 2 and testing of new 150 C junction temperature trench insulated gate bipolar transistor (IGBTs) in Section 3. Section 4 addresses some operational OPAL-GT information, which was necessary for developing module level tests. Section 5 summarizes calibration of equipment needed for the high temperature testing. Section 6 details some additional work that was funded on silicon carbide (SiC) device testing for high temperature use, and Section 7 is the complete text of a report funded from this effort summarizing packaging methods and their reliability issues for use in high temperature power electronics. Components were tested to evaluate the performance characteristics of the component at different operating temperatures. The temperature of the component is determined by the ambient temperature (i.e., temperature surrounding the device) plus the

  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. Magnetic memory effects in high temperature superconductors

    International Nuclear Information System (INIS)

    Rockenbauer, A.

    1989-01-01

    Microwave absorption of high temperature oxide superconductors MBa 2 Cu 3 O 7 (M = Y, Er, Dy, Ho, Lu, Tm, Gd) at 77 K have been studied by ESR. In granular samples diamagnetic zero-field resonance and strong ESR baseline hysteresis have been observed: for increasing field sweep - a high, for decreasing one - a low, while in constant field the baseline approaches the middle position with kinetics typical of spin-glasses. The hysteresis amplitude, i.e. the deviation of high and low baselines, possesses maximum at zero field if the sample is cooled down in zero field. In case of field cooling both the diamagnetic resonance and hysteresis maximum are shifted as a function of relative direction of the fields where the samples are cooled and measured, respectively. The shift is caused by the remanent diamagnetism of trapped fluxons. The hysteresis critically depends on the modulation amplitude of magnetic field, and no hysteresis can be observed if the microwave absorption is detected without field modulation. By applying saw-tooth sweep the spin-glass can be driven between two extreme hysteresis states, and the ESR response is rectangular for large saw-tooth amplitude and linear - for small one, while for intermediate amplitudes the recording shows characteristic memory effects. The hysteresis memory is explained in terms of loop distribution of fluxons. In the single crystal the fluxon absorptions are also detected and the separation of fluxon lines can be related to the hysteresis in granular samples. (author)

  14. Aspects of high temperature superconductivity

    International Nuclear Information System (INIS)

    Deutscher, G.

    1989-01-01

    We present some remarks on special features that distinguish the phenomenology of the new high T c oxides from that of the conventional superconductors. They include a measurable width of the critical region and a high sensitivity to crystallographic defects. A consistent Landau Ginsburg interpretation is possible, with a short coherence length <15 A and a penetration depth <900 A. The latter is somewhat smaller than the currently accepted value, and implies a broad band scheme

  15. Fusion blanket high-temperature heat transfer

    International Nuclear Information System (INIS)

    Fillo, J.A.

    1983-01-01

    Deep penetration of 14 MeV neutrons makes two-temperature region blankets feasible. A relatively low-temperature (approx. 300 0 C) metallic structure is the vacuum/coolant pressure boundary, while the interior of the blanket, which is a simple packed bed of nonstructural material, operates at very high temperatures (>1000 0 C). The water-cooled shell structure is thermally insulated from the steam-cooled interior. High-temperature steam can dramatically increase the efficiency of electric power generation, as well as produce hydrogen and oxygen-based synthetic fuels at high-efficiency

  16. Neutron diffraction under high pressure and high temperature

    International Nuclear Information System (INIS)

    Komatsu, Kazuki

    2010-01-01

    Neutron diffraction study under high pressure and high temperature is reviewed from the technical point of view. Particularly, cell assembly for the high-PT neutron diffraction using a Paris-Edinburgh cell with the temperature calibration by neutron resonance spectroscopy is introduced. Notes on the errors relevant to high pressure and high temperature experiments in both monochromatic angle dispersive and time-of-flight methods are also discussed. (author)

  17. High Temperature Rechargeable Battery Development, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This small business innovation research is intended to develop and proof the concept of a highly efficient, high temperature rechargeable battery for supporting...

  18. High Temperature Electrostrictive Ceramics, Phase I

    Data.gov (United States)

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

  19. High Temperature Stirling Cooler, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Although Honeybee and others have made huge advances in developing mechanisms, motors, and electronics for use in high temperature/high pressure environments such as...

  20. High temperature stability of materials and structures

    International Nuclear Information System (INIS)

    Solomin, N.V.

    1980-01-01

    The problems of high temperature resistance of materials under the effect of mechanic and thermomechanic stresses are considered as well as the resistance of elements of constructions to high temperature inelastic deformation under loading. New experimental data on material properties are presented, the original technique for calculating inelastic deformation of particular bodies is presented [ru

  1. A comparative study of single-temperature and two-temperature accretion flows around black holes

    Science.gov (United States)

    Dihingia, Indu Kalpa; Das, Santabrata; Mandal, Samir

    2018-02-01

    We study the properties of sub-Keplerian accretion disk around a stationary black hole, considering bremsstrahlung, synchrotron and Comptonization of synchrotron photons as radiative cooling mechanisms active in the disk. We obtain the solutions of two-temperature global accretion flow (TTAF) and compare it with the results obtained from single-temperature (STAF) model. We observe that flow properties, in particular, the radial profile of electron and ion temperatures differ noticeably in the adopted models for flows with identical boundary conditions fixed at the outer edge of the disk. Since the electron temperature is one of the key factors to regulate the radiative processes, we argue that physically motivated description of electron temperature needs to be considered in studying the astrophysical phenomena around black holes.

  2. High temperature solar selective coatings

    Science.gov (United States)

    Kennedy, Cheryl E

    2014-11-25

    Improved solar collectors (40) comprising glass tubing (42) attached to bellows (44) by airtight seals (56) enclose solar absorber tubes (50) inside an annular evacuated space (54. The exterior surfaces of the solar absorber tubes (50) are coated with improved solar selective coatings {48} which provide higher absorbance, lower emittance and resistance to atmospheric oxidation at elevated temperatures. The coatings are multilayered structures comprising solar absorbent layers (26) applied to the meta surface of the absorber tubes (50), typically stainless steel, topped with antireflective Savers (28) comprising at least two layers 30, 32) of refractory metal or metalloid oxides (such as titania and silica) with substantially differing indices of refraction in adjacent layers. Optionally, at least one layer of a noble metal such as platinum can be included between some of the layers. The absorbent layers cars include cermet materials comprising particles of metal compounds is a matrix, which can contain oxides of refractory metals or metalloids such as silicon. Reflective layers within the coating layers can comprise refractory metal silicides and related compounds characterized by the formulas TiSi. Ti.sub.3SiC.sub.2, TiAlSi, TiAN and similar compounds for Zr and Hf. The titania can be characterized by the formulas TiO.sub.2, Ti.sub.3O.sub.5. TiOx or TiO.sub.xN.sub.1-x with x 0 to 1. The silica can be at least one of SiO.sub.2, SiO.sub.2x or SiO.sub.2xN.sub.1-x with x=0 to 1.

  3. High temperature superconductors in electromagnetic applications

    International Nuclear Information System (INIS)

    Richens, P.E.

    2000-01-01

    The design, construction, and characterization of a High Temperature Superconducting (HTS) magnet is described. The design stage has involved the development of computer software for the calculation of the critical current of a solenoid wound from anisotropic HTS conductor. This calculation can be performed for a variety of problems including those involving magnetic materials such as iron by the incorporation of finite element electromagnetic analysis software. This has enabled the optimization of the magnet's performance. The HTS magnet is wound from 190 m of silver-matrix Bi 2 Sr 2 Ca 2 Cu 3 O 10 powder-in-tube tape conductor supplied by Intermagnetics General Corporation. The dimensions are 70 mm bore and 70 mm length, and it consists of 728 turns. Iron end-plates were utilized in order to reduce the radial magnetic field, and consequently increase the performance by ∼ 20%. The magnet has been operated in liquid cryogens and has achieved engineering current densities of 900 A cm -2 at 77 K and 6680 A cm -2 at 4.2 K. The HTS magnet has been operated by conduction-cooling on a mechanical refrigerator at various temperatures in the range 12 to 50 K. The thermal stability in this relatively low cooling-power system has been assessed. An engineering current density of 5600 A cm -2 was achieved at 12 K. Measurements of the strain dependence of the critical current in a variety of HTS conductors, including powder-in-tube and dip-coated, have been made using a novel single loop tensometer that enables the insertion of a reasonably long length of conductor into the bore of a high-field magnet. (author)

  4. Recrystallization of high temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kouzoudis, Dimitris [Iowa State Univ., Ames, IA (United States)

    1996-05-09

    Currently one of the most widely used high Tc superconductors is the Bi-based compounds Bi2Sr2CaCu2Oz and Bi2Sr2Ca2Cu3Oz (known as BSCCO 2212 and 2223 compounds) with Tc values of about 85 K and 110 K respectively. Lengths of high performance conductors ranging from 100 to 1000 m long are routinely fabricated and some test magnets have been wound. An additional difficulty here is that although Bi-2212 and Bi-2223 phases exist over a wide range of stoichiometries, neither has been prepared in phase-pure form. So far the most successful method of constructing reliable and robust wires or tapes is the so called powder-in-tube (PIT) technique [1, 2, 3, 4, 5, 6, 7] in which oxide powder of the appropriate stoichiometry and phase content is placed inside a metal tube, deformed into the desired geometry (round wire or flat tape), and annealed to produce the desired superconducting properties. Intermediate anneals are often incorporated between successive deformation steps. Silver is the metal used in this process because it is the most compatible with the reacting phase. In all of the commercial processes for BSCCO, Ag seems to play a special catalytic role promoting the growth of high performance aligned grains that grow in the first few micrometers near the Ag/BSCCO interface. Adjacent to the Ag, the grain alignment is more perfect and the current density is higher than in the center of the tape. It is known that Ag lowers the melting point of several of the phases but the detailed mechanism for growth of these high performance grains is not clearly understood. The purpose of this work is to study the nucleation and growth of the high performance material at this interface.

  5. High temperature impedance spectroscopy of barium stannate ...

    Indian Academy of Sciences (India)

    temperature solid-state reac- tion technique. X-ray diffraction analysis indicated the formation of a single-phase cubic structure with lattice parameter: a = (4·1158 ± 0·0003) .... the equation for the impedance of this circuit. Z = Z − jZ = (. 1/Rg + jωCg. )−1.

  6. High temperature superconductors in electromagnetic applications

    CERN Document Server

    Richens, P E

    2000-01-01

    powder-in-tube and dip-coated, have been made using a novel single loop tensometer that enables the insertion of a reasonably long length of conductor into the bore of a high-field magnet. The design, construction, and characterization of a High Temperature Superconducting (HTS) magnet is described. The design stage has involved the development of computer software for the calculation of the critical current of a solenoid wound from anisotropic HTS conductor. This calculation can be performed for a variety of problems including those involving magnetic materials such as iron by the incorporation of finite element electromagnetic analysis software. This has enabled the optimization of the magnet's performance. The HTS magnet is wound from 190 m of silver-matrix Bi sub 2 Sr sub 2 Ca sub 2 Cu sub 3 O sub 1 sub 0 powder-in-tube tape conductor supplied by Intermagnetics General Corporation. The dimensions are 70 mm bore and 70 mm length, and it consists of 728 turns. Iron end-plates were utilized in order to reduc...

  7. High temperature effects on compact-like structures

    Energy Technology Data Exchange (ETDEWEB)

    Bazeia, D.; Lima, E.E.M.; Losano, L. [Universidade Federal da Paraiba, Departamento de Fisica, Joao Pessoa, PB (Brazil)

    2016-08-15

    In this work we investigate the transition from kinks to compactons at high temperatures. We deal with a family of models, described by a real scalar field with standard kinematics, controlled by a single parameter, real and positive. The family of models supports kink-like solutions, and the solutions tend to become compact when the parameter increases to larger and larger values. We study the one-loop corrections at finite temperature, to see how the thermal effects add to the effective potential. The results suggest that the symmetry is restored at very high temperatures. (orig.)

  8. High-temperature superconductivity of granulated metals

    CERN Document Server

    Mejlikhov, E Z

    2001-01-01

    Only the area of relatively low temperatures was traditionally considered in the theoretical ands experimental studies on the nanocomposites (granulated metals) conductivity, related to the intergranular electrons tunneling. The conductivity temperature dependence in this mode is exponential. However, according to the experiment the character of the nanocomposites conductivity at higher temperatures essentially changes. The model, relating the peculiarities of the granulated metals conductivity at high temperatures, to the involvement of the multicharged granules in this process under the conditions of high spread of their sizes, is proposed. The model conclusions are in agreement with the experiment

  9. Microwave-assisted wet digestion with H2O2 at high temperature and pressure using single reaction chamber for elemental determination in milk powder by ICP-OES and ICP-MS.

    Science.gov (United States)

    Muller, Edson I; Souza, Juliana P; Muller, Cristiano C; Muller, Aline L H; Mello, Paola A; Bizzi, Cezar A

    2016-08-15

    In this work a green digestion method which only used H2O2 as an oxidant and high temperature and pressure in the single reaction chamber system (SRC-UltraWave™) was applied for subsequent elemental determination by inductively coupled plasma-based techniques. Milk powder was chosen to demonstrate the feasibility and advantages of the proposed method. Samples masses up to 500mg were efficiently digested, and the determination of Ca, Fe, K, Mg and Na was performed by inductively coupled plasma optical emission spectrometry (ICP-OES), while trace elements (B, Ba, Cd, Cu, Mn, Mo, Pb, Sr and Zn) were determined by inductively coupled plasma mass spectrometry (ICP-MS). Residual carbon (RC) lower than 918mgL(-1) of C was obtained for digests which contributed to minimizing interferences in determination by ICP-OES and ICP-MS. Accuracy was evaluated using certified reference materials NIST 1549 (non-fat milk powder certified reference material) and NIST 8435 (whole milk powder reference material). The results obtained by the proposed method were in agreement with the certified reference values (t-test, 95% confidence level). In addition, no significant difference was observed between results obtained by the proposed method and conventional wet digestion using concentrated HNO3. As digestion was performed without using any kind of acid, the characteristics of final digests were in agreement with green chemistry principles when compared to digests obtained using conventional wet digestion method with concentrated HNO3. Additionally, H2O2 digests were more suitable for subsequent analysis by ICP-based techniques due to of water being the main product of organic matrix oxidation. The proposed method was suitable for quality control of major components and trace elements present in milk powder in consonance with green sample preparation. Copyright © 2016 Elsevier B.V. All rights reserved.

  10. Impedance analysis and high temperature conduction mechanism of flux grown Pb(Zn{sub 1/3}Nb{sub 2/3}){sub 0.91}Ti{sub 0.09}O{sub 3} single crystal

    Energy Technology Data Exchange (ETDEWEB)

    Singh, B.K.; Kumar, B. [Crystal Lab., Dept. of Physics and Astrophysics, University of Delhi (India)

    2010-10-15

    The electrical properties of Pb(Zn{sub 1/3} Nb{sub 2/3}){sub 0.91}Ti{sub 0.09}O{sub 3} single crystals over a wide range of frequencies (20 Hz to 2 MHz) and temperature (30 to 490 C) were studied using impedance spectroscopic technique. A strongly frequency dependant Debye type relaxation process in crystals was observed. The activation energy for relaxation was found to be 1.72 eV. The nature of Cole-Cole plot reveals the contribution of only grain (bulk) effect in the sample. The temperature dependant conductivity was found to different in different temperature regions, which shows the presence of different carrier for conduction. The activation energy for conduction in the order of 1.69 eV suggested that the conduction process in higher temperature region is governed by the presence of lead vacancy defect in the sample. Further, the negative temperature thermistor behaviour of the system was explored and various associated parameters were calculated. (copyright 2010 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  11. Sandia_HighTemperatureComponentEvaluation_2015

    Energy Technology Data Exchange (ETDEWEB)

    Cashion, Avery T. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2015-03-01

    The objective of this project is to perform independent evaluation of high temperature components to determine their suitability for use in high temperature geothermal tools. Development of high temperature components has been increasing rapidly due to demand from the high temperature oil and gas exploration and aerospace industries. Many of these new components are at the late prototype or first production stage of development and could benefit from third party evaluation of functionality and lifetime at elevated temperatures. In addition to independent testing of new components, this project recognizes that there is a paucity of commercial-off-the-shelf COTS components rated for geothermal temperatures. As such, high-temperature circuit designers often must dedicate considerable time and resources to determine if a component exists that they may be able to knead performance out of to meet their requirements. This project aids tool developers by characterization of select COTS component performances beyond published temperature specifications. The process for selecting components includes public announcements of project intent (e.g., FedBizOps), direct discussions with candidate manufacturers,and coordination with other DOE funded programs.

  12. Viscoelastic creep of high-temperature concrete

    International Nuclear Information System (INIS)

    Pfeiffer, P.A.; Marchertas, A.H.; Bazant, Z.P.

    1985-01-01

    Presented in this report is the analytical model for analysis of high temperature creep response of concrete. The creep law used is linear (viscoelastic), the temperature and moisture effects on the creep rate and also aging are included. Both constant and transient temperature as well as constant and transient moisture conditions are considered. Examples are presented to correlate experimental data with parameters of the analytical model by the use of a finite element scheme

  13. High temperature thermometric phosphors for use in a temperature sensor

    Science.gov (United States)

    Allison, Stephen W.; Cates, Michael R.; Boatner, Lynn A.; Gillies, George T.

    1998-01-01

    A high temperature phosphor consists essentially of a material having the general formula LuPO.sub.4 :Dy.sub.(x),Eu.sub.(y), wherein: 0.1 wt %.ltoreq.x.ltoreq.20 wt % and 0.1 wt %.ltoreq.y.ltoreq.20 wt %. The high temperature phosphor is in contact with an article whose temperature is to be determined. The article having the phosphor in contact with it is placed in the environment for which the temperature of the article is to be determined. The phosphor is excited by a laser causing the phosphor to fluoresce. The emission from the phosphor is optically focused into a beam-splitting mirror which separates the emission into two separate emissions, the emission caused by the dysprosium dopant and the emission caused by the europium dopent. The separated emissions are optically filtered and the intensities of the emission are detected and measured. The ratio of the intensity of each emission is determined and the temperature of the article is calculated from the ratio of the intensities of the separate emissions.

  14. Tunable room-temperature single photon emission from atomic defects in hexagonal boron nitride

    Science.gov (United States)

    Grosso, Gabriele; Moon, Hyowon; Lienhard, Benjamin; Efetov, Dmitri; Furchi, Marco; Jarillo-Herrero, Pablo; Ali, Sajid; Ford, Michael; Aharonovich, Igor; Englund, Dirk

    Two-dimensional van der Waals materials have emerged as promising platforms for solid-state quantum information processing devices with unusual potential for heterogeneous assembly. Recently, bright and photostable single photon emitters were reported from atomic defects in layered hexagonal boron nitride (hBN), but controlling inhomogeneous spectral distribution and reducing multi-photon emission presented open challenges. We demonstrate that strain control allows spectral tunability of hBN single photon emitters, and material processing sharply improves the single-photon purity. Our sample fabrication process relies on ion irradiation and high temperature annealing to isolate individual defects for single photon emission. Spectroscopy on this emitter reports high single photon purity of g(2)(0) =0.07, and high count rates exceeding 107 counts/sec at saturation. Furthermore, these emitters are stable to material transfer to other substrates, including a bendable beam that allows us to controllably apply strain. Our experiments indicate a maximum tuning of 6 meV and emission energy dependencies ranging from -3 to 6 meV/%. High-purity and photostable single photon emission at room temperature, together with spectral tunability and transferability, opens the door to scalable integration of high-quality quantum emitters in photonic quantum technologies.

  15. Aeronautical applications of high-temperature superconductors

    Science.gov (United States)

    Turney, George E.; Luidens, Roger W.; Uherka, Kenneth; Hull, John

    1989-01-01

    The successful development of high-temperature superconductors (HTS) could have a major impact on future aeronautical propulsion and aeronautical flight vehicle systems. A preliminary examination of the potential application of HTS for aeronautics indicates that significant benefits may be realized through the development and implementation of these newly discovered materials. Applications of high-temperature superconductors (currently substantiated at 95 k) were envisioned for several classes of aeronautical systems, including subsonic and supersonic transports, hypersonic aircraft, V/STOL aircraft, rotorcraft, and solar, microwave and laser powered aircraft. Introduced and described are the particular applications and potential benefits of high-temperature superconductors as related to aeronautics and/or aeronautical systems.

  16. High temperature solid state storage cell

    Science.gov (United States)

    Rea, Jesse R.; Kallianidis, Milton; Kelsey, G. Stephen

    1983-01-01

    A completely solid state high temperature storage cell comprised of a solid rechargeable cathode such as TiS.sub.2, a solid electrolyte which remains solid at the high temperature operating conditions of the cell and which exhibits high ionic conductivity at such elevated temperatures such as an electrolyte comprised of lithium iodide, and a solid lithium or other alkali metal alloy anode (such as a lithium-silicon alloy) with 5-50% by weight of said anode being comprised of said solid electrolyte.

  17. 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

  18. 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.

  19. Silicon Carbide Nanotube Oxidation at High Temperatures

    Science.gov (United States)

    Ahlborg, Nadia; Zhu, Dongming

    2012-01-01

    Silicon Carbide Nanotubes (SiCNTs) have high mechanical strength and also have many potential functional applications. In this study, SiCNTs were investigated for use in strengthening high temperature silicate and oxide materials for high performance ceramic nanocomposites and environmental barrier coating bond coats. The high · temperature oxidation behavior of the nanotubes was of particular interest. The SiCNTs were synthesized by a direct reactive conversion process of multiwall carbon nanotubes and silicon at high temperature. Thermogravimetric analysis (TGA) was used to study the oxidation kinetics of SiCNTs at temperatures ranging from 800degC to1300degC. The specific oxidation mechanisms were also investigated.

  20. 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

  1. Single-Antenna Temperature- and Humidity-Sounding Microwave Receiver

    Science.gov (United States)

    Hoppe, Daniel J.; Pukala, David M.; Lambrigtsen, Bjorn H.; Soria, Mary M.; Owen, Heather R.; Tanner, Alan B.; Bruneau, Peter J.; Johnson, Alan K.; Kagaslahti, Pekka P.; Gaier, Todd C.

    2011-01-01

    For humidity and temperature sounding of Earth s atmosphere, a single-antenna/LNA (low-noise amplifier) is needed in place of two separate antennas for the two frequency bands. This results in significant mass and power savings for GeoSTAR that is comprised of hundreds of antennas per frequency channel. Furthermore, spatial anti-aliasing would reduce the number of horns. An anti-aliasing horn antenna will enable focusing the instrument field of view to the hurricane corridor by reducing spatial aliasing, and thus reduce the number of required horns by up to 50 percent. The single antenna/receiver assembly was designed and fabricated by a commercial vendor. The 118 183-GHz horn is based upon a profiled, smooth-wall design, and the OMT (orthomode transducer) on a quad-ridge design. At the input end, the OMT presents four ver y closely spaced ridges [0.0007 in. (18 m)]. The fabricated assembly contains a single horn antenna and low-noise broadband receiver front-end assembly for passive remote sensing of both temperature and humidity profiles in the Earth s atmosphere at 118 and 183 GHz. The wideband feed with dual polarization capability is the first broadband low noise MMIC receiver with the 118 to 183 GHz bandwidth. This technology will significantly reduce PATH/GeoSTAR mass and power while maintaining 90 percent of the measurement capabilities. This is required for a Mission-of-Opportunity on NOAA s GOES-R satellite now being developed, which in turn will make it possible to implement a Decadal-Survey mission for a fraction of the cost and much sooner than would otherwise be possible.

  2. High temperature ceramic/metal joint structure

    Science.gov (United States)

    Boyd, Gary L. (Inventor)

    1991-01-01

    A high temperature turbine engine includes a hybrid ceramic/metallic rotor member having ceramic/metal joint structure. The disclosed joint is able to endure higher temperatures than previously possible, and aids in controlling heat transfer in the rotor member.

  3. High temperatures influence sexual development differentially in ...

    Indian Academy of Sciences (India)

    Samadhan Krushna Phuge

    2017-06-20

    Jun 20, 2017 ... These results suggest that high temperature probably acts through stress hormones and favours the small-sized sex. Keywords. Euphlyctis cyanophlyctis; gonadal development; metamorphosis; sex ratio; temperature-dependent sex determination. 1. Introduction. The process of gonadal sex determination ...

  4. Technology development for high temperature logging tools

    Energy Technology Data Exchange (ETDEWEB)

    Veneruso, A.F.; Coquat, J.A.

    1979-01-01

    A set of prototype, high temperature logging tools (temperature, pressure and flow) were tested successfully to temperatures up to 275/sup 0/C in a Union geothermal well during November 1978 as part of the Geothermal Logging Instrumentation Development Program. This program is being conducted by Sandia Laboratories for the Department of Energy's Division of Geothermal Energy. The progress and plans of this industry based program to develop and apply the high temperature instrumentation technology needed to make reliable geothermal borehole measurements are described. Specifically, this program is upgrading existing sondes for improved high temperature performance, as well as applying new materials (elastomers, polymers, metals and ceramics) and developing component technology such as high temperature cables, cableheads and electronics to make borehole measurements such as formation temperature, flow rate, high resolution pressure and fracture mapping. In order to satisfy critical existing needs, the near term goal is for operation up to 275/sup 0/C and 7000 psi by the end of FY80. The long term goal is for operation up to 350/sup 0/C and 20,000 psi by the end of FY84.

  5. Low Temperature Heating and High Temperature Cooling in Buildings

    DEFF Research Database (Denmark)

    Kazanci, Ongun Berk

    , a holistic system evaluation is necessary to ensure an optimal indoor environment for the occupants and to achieve energy efficiency simultaneously. Low temperature heating and high temperature cooling systems are one of the possible approaches to heat or cool indoor spaces in buildings. In this thesis...... were monitored for one year while different control strategies were tested. Theoretical analyses consisted of comparing the performance of different heating and cooling systems using energy, exergy, and entransy methods under steady-state conditions. Dynamic simulations were used to study the energy...... performance of heating and cooling systems for achieving the same thermal indoor environment. The results show that it is crucial to minimize the heating and cooling demands in the design phase since these demands determine the terminal units and heat sources and sinks that could be used. Low temperature...

  6. High Temperature Superconductor Bolometers for Planetary Science

    Data.gov (United States)

    National Aeronautics and Space Administration — This work is a design study of an instrument optimized for JPL's novel high temperature superconductor bolometers. The work involves designing an imaging...

  7. Ion Based High-Temperature Pressure Sensor

    National Research Council Canada - National Science Library

    Zdenek, Jeffrey S; Anthenien, Ralph A

    2004-01-01

    .... The environment encountered in such engines necessitates high temperature and durable (vibration resistant) devices. Traditional pressure sensors can be used, however thermal insulating materials must be used to protect the diaphragm...

  8. High Temperature Bell Motor, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — The National Research Council (NRC) has identified the need for motors and actuators that can operate in extreme high and low temperature environments as a technical...

  9. Panel report on high temperature ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Nolet, T C [ed.

    1979-01-01

    Fundamental research is reported concerning high temperature ceramics for application in turbines, engines, batteries, gasifiers, MHD, fuel cells, heat exchangers, and hot wall combustors. Ceramics microstructure and behavior are included. (FS)

  10. Novel High Temperature Strain Gauge, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Advanced high-temperature sensor technology and bonding methods are of great interests in designing and developing advanced future aircraft. Current state-of-the-art...

  11. High temperature energy harvester for wireless sensors

    International Nuclear Information System (INIS)

    E Köhler, J; Heijl, R; Staaf, L G H; Palmqvist, A E C; Enoksson, P; Zenkic, S; Svenman, E; Lindblom, A

    2014-01-01

    Implementing energy harvesters and wireless sensors in jet engines will simplify development and decrease costs by reducing the need for cables. Such a device could include a small thermoelectric generator placed in the cooling channels of the jet engine where the temperature is between 500–900 °C. This paper covers the synthesis of suitable thermoelectric materials, design of module and proof of concept tests of a thermoelectric module. The materials and other design variables were chosen based on an analytic model and numerical analysis. The module was optimized for 600–800 °C with the thermoelectric materials n-type Ba 8 Ga 16 Ge 30 and p-type La-doped Yb 14 MnSb 11 , both with among the highest reported figure-of-merit values, zT, for bulk materials in this region. The materials were synthesized and their structures confirmed by x-ray diffraction. Proof of concept modules containing only two thermoelectric legs were built and tested at high temperatures and under high temperature gradients. The modules were designed to survive an ambient temperature gradient of up to 200 °C. The first measurements at low temperature showed that the thermoelectric legs could withstand a temperature gradient of 123 °C and still be functional. The high temperature measurement with 800 °C on the hot side showed that the module remained functional at this temperature. (paper)

  12. High temperature energy harvester for wireless sensors

    Science.gov (United States)

    Köhler, J. E.; Heijl, R.; Staaf, L. G. H.; Zenkic, S.; Svenman, E.; Lindblom, A.; Palmqvist, A. E. C.; Enoksson, P.

    2014-09-01

    Implementing energy harvesters and wireless sensors in jet engines will simplify development and decrease costs by reducing the need for cables. Such a device could include a small thermoelectric generator placed in the cooling channels of the jet engine where the temperature is between 500-900 °C. This paper covers the synthesis of suitable thermoelectric materials, design of module and proof of concept tests of a thermoelectric module. The materials and other design variables were chosen based on an analytic model and numerical analysis. The module was optimized for 600-800 °C with the thermoelectric materials n-type Ba8Ga16Ge30 and p-type La-doped Yb14MnSb11, both with among the highest reported figure-of-merit values, zT, for bulk materials in this region. The materials were synthesized and their structures confirmed by x-ray diffraction. Proof of concept modules containing only two thermoelectric legs were built and tested at high temperatures and under high temperature gradients. The modules were designed to survive an ambient temperature gradient of up to 200 °C. The first measurements at low temperature showed that the thermoelectric legs could withstand a temperature gradient of 123 °C and still be functional. The high temperature measurement with 800 °C on the hot side showed that the module remained functional at this temperature.

  13. Corrosion Inhibition in High Temperature Environment

    Science.gov (United States)

    1993-06-28

    nickel-based or 20 cobalt -based superalloys , or with ferric oxide from high 21 temperature steels, to produce spalling metal vanadates. 22 Similar hot...metallic 5 superalloy Rene 80, or a ceramic, such as silicon nitride or 6 silicon carbide . Rene 80 is a nickel-based superalloy used for gas 7 turbine... superalloys to form 9 nonprotective NaAlO 2 which causes catastrophic hot corrosion. High 10 temperature chromium-containing metals which rely on chromia

  14. High temperature superconductors and other superfluids

    CERN Document Server

    Alexandrov, A S

    2017-01-01

    Written by eminent researchers in the field, this text describes the theory of superconductivity and superfluidity starting from liquid helium and a charged Bose-gas. It also discusses the modern bipolaron theory of strongly coupled superconductors, which explains the basic physical properties of high-temperature superconductors. This book will be of interest to fourth year graduate and postgraduate students, specialist libraries, information centres and chemists working in high-temperature superconductivity.

  15. Mechanical Proprieties of Steel at High Temperatures

    Directory of Open Access Journals (Sweden)

    Ana-Diana Ancaş

    2005-01-01

    Full Text Available The experimental test results obtained in the study of steel mechanical proprieties variation in case of high temperatures (fire are presented. The proprieties are referring to: Young’s modulus, E, the elastic limit, σe, and the characteristic diagram of the material (the rotation stress-strain. Theoretical laws that the model the steel behaviour at high temperature have been elaborated based on the most significant studies presented in the literature.

  16. PLA recycling by hydrolysis at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Cristina, Annesini Maria; Rosaria, Augelletti; Sara, Frattari, E-mail: sara.frattari@uniroma1.it; Fausto, Gironi [Department of Chemical Engineering Materials Environment, University of Rome “La Sapienza”, Via Eudossiana 18– 00184 Roma (Italy)

    2016-05-18

    In this work the process of PLA hydrolysis at high temperature was studied, in order to evaluate the possibility of chemical recycling of this polymer bio-based. In particular, the possibility to obtain the monomer of lactic acid from PLA degradation was investigated. The results of some preliminary tests, performed in a laboratory batch reactor at high temperature, are presented: the experimental results show that the complete degradation of PLA can be obtained in relatively low reaction times.

  17. Preparation of high-temperature superconducting ceramics

    International Nuclear Information System (INIS)

    Causa, M.T.; Dutrus, S.M.; Esparza, Daniel; Fainstein, Carlos; Malachevsky, M.T.; Salva, Horacio; Sanchez, Rodolfo; Steren, L.B.; Tovar, Manuel; Veglio, Nestor

    1987-01-01

    We have prepared samples of the family ABa2Cu3Ox (A=Y, Gd, Eu, Dy, Sm, Er). The powdered samples were characterized by X-ray diffraction at room temperature. We have also studied the effect of Fe impurities in YBa2Cu3Ox and EuBa2Cu3Ox. Moreover, single crystals of YBa2Cu3Ox and La(1-x)SrxCuO4 were grown using cooper oxide flux. (Author) [es

  18. High-temperature spreading kinetics of metals

    Energy Technology Data Exchange (ETDEWEB)

    Rauch, N.

    2005-05-15

    In this PhD work a drop transfer setup combined with high speed photography has been used to analyze the spreading of Ag on polished polycrystalline Mo and single crystalline Mo (110) and (100) substrates. The objective of this work was to unveil the basic phenomena controlling spreading in metal-metal systems. The observed spreading kinetics were compared with current theories of low and high temperature spreading such as a molecular kinetic model and a fluid flow model. Analyses of the data reveal that the molecular model does describe the fastest velocity data well for all the investigated systems. Therefore, the energy which is dissipated during the spreading process is a dissipation at the triple line rather than dissipation due to the viscosity in the liquid. A comparison of the determined free activation energy for wetting of {delta}G95{approx}145kJ/mol with literature values allows the statement that the rate determining step seems to be a surface diffusion of the Ag atoms along the triple line. In order to investigate possible ridge formation, due to local atomic diffusion of atoms of the substrate at the triple during the spreading process, grooving experiments of the polycrystalline Mo were performed to calculate the surface diffusities that will control ridge evolution. The analyses of this work showed that a ridge formation at the fastest reported wetting velocities was not possible if there is no initial perturbation for a ridge. If there was an initial perturbation for a ridge the ridge had to be much smaller than 1 nm in order to be able to move with the liquid font. Therefore ridge formation does not influence the spreading kinetics for the studied system and the chosen conditions. SEM, AFM and TEM investigations of the triple line showed that ridge formation does also not occur at the end of the wetting experiment when the drop is close to equilibrium and the wetting velocity is slow. (orig.)

  19. Melt processed high-temperature superconductors

    CERN Document Server

    1993-01-01

    The achievement of large critical currents is critical to the applications of high-temperature superconductors. Recent developments have shown that melt processing is suitable for producing high J c oxide superconductors. Using magnetic forces between such high J c oxide superconductors and magnets, a person could be levitated.This book has grown largely out of research works on melt processing of high-temperature superconductors conducted at ISTEC Superconductivity Research Laboratory. The chapters build on melt processing, microstructural characterization, fundamentals of flux pinning, criti

  20. Handbook of high-temperature superconductivity theory and experiment

    CERN Document Server

    Brooks, James S

    2007-01-01

    Since the 1980s, a general theme in the study of high-temperature superconductors has been to test the BCS theory and its predictions against new data. At the same time, this process has engendered new physics, new materials, and new theoretical frameworks. Remarkable advances have occurred in sample quality and in single crystals, in hole and electron doping in the development of sister compounds with lower transition temperatures, and in instruments to probe structure and dynamics. Handbook of High-Temperature Superconductvity is a comprehensive and in-depth treatment of both experimental and theoretical methodologies by the the world's top leaders in the field. The Editor, Nobel Laureate J. Robert Schrieffer, and Associate Editor James S. Brooks, have produced a unified, coherent work providing a global view of high-temperature superconductivity covering the materials, the relationships with heavy-fermion and organic systems, and the many formidable challenges that remain.

  1. Single-bubble sonoluminescence as Dicke superradiance at finite temperature

    Science.gov (United States)

    Aparicio Alcalde, M.; Quevedo, H.; Svaiter, N. F.

    2014-12-01

    Sonoluminescence is a process in which a strong sound field is used to produce light in liquids. We explain sonoluminescence as a phase transition from ordinary fluorescence to a superradiant phase. We consider a spin-boson model composed of a single bosonic mode and an ensemble of N identical two-level atoms. We assume that the whole system is in thermal equilibrium with a reservoir at temperature β-1. We show that, in a ultrastrong-coupling regime, between the two-level atoms and the electromagnetic field it is possible to have a cooperative interaction of the molecules of the gas in the interior of the bubble with the field, generating sonoluminescence.

  2. Decay properties of high-lying single-particles modes

    NARCIS (Netherlands)

    Beaumel, D; Fortier, S; Gales, S; Guillot, J; LangevinJoliot, H; Laurent, H; Maison, JM; Vernotte, J; Bordewijck, J; Brandenburg, S; Krasznahorkay, A; Crawley, GM; Massolo, CP; Renteria, M; Khendriche, A

    1996-01-01

    The neutron decay of high-lying single-particle states in Ni-64, Zr-90, Sn-120 and (208)pb excited by means of the (alpha,He-3) reaction has been investigated at 120 MeV incident energy using the multidetector EDEN. The characteristics of this reaction are studied using inclusive spectra and angular

  3. High pressure study of high-temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Souliou, Sofia-Michaela

    2014-09-29

    Imm2). The structural transition is clearly reflected in the high pressure Raman data through the appearance of several new modes, allowing us to map in detail the (P,T) phase diagram and determine the transition line between the two phases. In the new phase, the renormalization of the buckling mode is completely suppressed, while no anomalies are observed in any of the other Raman active phonons. According to ab initio calculations, the coupling of the buckling mode to the electronic system is not significantly affected by the structural phase transition. The absence of phonon renormalizations in the presence of sizable electron-phonon coupling, indicate that, in contrast to earlier transport studies, YBa{sub 2}Cu{sub 4}O{sub 8} is not superconducting anymore under hydrostatic pressures higher than 10 GPa. Finally we proceeded with the investigation of the high pressure structural and vibrational properties of SmFeAsO, a member of the ''1111'' family (space group P4/nmm) of the Fe-based superconductors, in which superconductivity is commonly induced either by substituting F/H for O or by applying high pressures on the parent magnetic compound. The magnetic transition of the undoped compound is accompanied with a tetragonal-to-orthorhombic structural distortion, both of which are commonly suppressed upon the emergence of superconductivity. In the SmFeAsO{sub x}F{sub 1-x} system while the magnetic transition is totally suppressed already at low doping levels, structural studies have reported either the gradual suppression of the orthorhombic distortion or its retention over a wide regime of the superconducting phase. We addressed this controversy using high pressure as an alternative tuning parameter to suppress the magneto-structural transition and induce superconductivity in the parent compound. Our high pressure, low temperature X-ray diffraction measurements on single crystals of SmFeAsO have revealed that the tetragonal

  4. Single shot high resolution digital holography.

    Science.gov (United States)

    Khare, Kedar; Ali, P T Samsheer; Joseph, Joby

    2013-02-11

    We demonstrate a novel computational method for high resolution image recovery from a single digital hologram frame. The complex object field is obtained from the recorded hologram by solving a constrained optimization problem. This approach which is unlike the physical hologram replay process is shown to provide high quality image recovery even when the dc and the cross terms in the hologram overlap in the Fourier domain. Experimental results are shown for a Fresnel zone hologram of a resolution chart, intentionally recorded with a small off-axis reference beam angle. Excellent image recovery is observed without the presence of dc or twin image terms and with minimal speckle noise.

  5. High-temperature granulites and supercontinents

    Directory of Open Access Journals (Sweden)

    J.L.R. Touret

    2016-01-01

    Full Text Available The formation of continents involves a combination of magmatic and metamorphic processes. These processes become indistinguishable at the crust-mantle interface, where the pressure-temperature (P-T conditions of (ultra high-temperature granulites and magmatic rocks are similar. Continents grow laterally, by magmatic activity above oceanic subduction zones (high-pressure metamorphic setting, and vertically by accumulation of mantle-derived magmas at the base of the crust (high-temperature metamorphic setting. Both events are separated from each other in time; the vertical accretion postdating lateral growth by several tens of millions of years. Fluid inclusion data indicate that during the high-temperature metamorphic episode the granulite lower crust is invaded by large amounts of low H2O-activity fluids including high-density CO2 and concentrated saline solutions (brines. These fluids are expelled from the lower crust to higher crustal levels at the end of the high-grade metamorphic event. The final amalgamation of supercontinents corresponds to episodes of ultra-high temperature metamorphism involving large-scale accumulation of these low-water activity fluids in the lower crust. This accumulation causes tectonic instability, which together with the heat input from the sub-continental lithospheric mantle, leads to the disruption of supercontinents. Thus, the fragmentation of a supercontinent is already programmed at the time of its amalgamation.

  6. alpha- and beta-FOX-7, polymorphs of a high energy density material, studied by X-ray single crystal and powder investigations in the temperature range from 200 to 423 K.

    Science.gov (United States)

    Evers, Jürgen; Klapötke, Thomas M; Mayer, Peter; Oehlinger, Gilbert; Welch, Jan

    2006-06-26

    The alpha-beta phase transition in the novel energetic material 1,1-diamino-2,2-dinitroethylene, C2H4N4O4 (FOX-7), has been studied by single-crystal X-ray investigations at five different temperatures over the 200-393 K range. In these investigations, the positions of the hydrogen atoms were experimentally determined without any geometric constraints. In addition, X-ray powder investigations using the Guinier technique have been performed to characterize the beta-phase up to 423 K. The alpha-beta phase transition at 389 K is first order, shows a discontinuous increase of the molar volume and entropy (DeltaV = 1.75 cm3/mol, X-ray investigation; DeltaS = 1.5 cal/K mol, DSC analysis), and can be classified as displacive. The hitherto unknown structure of beta-FOX-7 was solved at 393 K and showed simple structural relations to the alpha-polymorph. The characteristic bonding in wave-shaped layers is now found for beta-FOX-7 (P2(1)2(1)2(1), z = 4, a= 6.9738(7) A, b = 6.635(1) A, c = 11.648(2) A, 393 K), as well as for alpha-FOX-7 (P2(1)/n, z = 4, a = 6.9467(7) A, b = 6.6887(9) A, c = 11.350(1) A, beta = 90.143(13) degrees , 373 K). Interestingly, whereas the intramolecular C-C, C-N, N-O, and N-H bond distances remain nearly unchanged for both polymorphs over the whole temperature range from 200 to 393 K, the two nitro groups deviate strongly from the molecular plane formed by the two carbon and two amino nitrogen atoms. In alpha-FOX-7 at 373 K, the nitro groups are twisted -47 and +6 degrees with respect to the carbon-carbon bond, but in beta-FOX-7 at 393 K, these twist angles are changed to -36 and +20 degrees . Within the layers, the FOX-7 molecules show strong pi-conjugation and extensive intra- and intermolecular hydrogen bonding. In this investigation, we have been able to show that alpha- and beta-FOX-7 build up different nets of intermolecular hydrogen bonds. In alpha-FOX-7, each oxygen atom of the nitro groups is involved in two hydrogen bonds resulting in two

  7. High-temperature superconducting conductors and cables

    International Nuclear Information System (INIS)

    Peterson, D.E.; Maley, M.P.; Boulaevskii, L.; Willis, J.O.; Coulter, J.Y.; Ullmann, J.L.; Cho, Jin; Fleshler, S.

    1996-01-01

    This is the final report of a 3-year LDRD project at LANL. High-temperature superconductivity (HTS) promises more efficient and powerful electrical devices such as motors, generators, and power transmission cables; however this depends on developing HTS conductors that sustain high current densities J c in high magnetic fields at temperatures near liq. N2's bp. Our early work concentrated on Cu oxides but at present, long wire and tape conductors can be best made from BSCCO compounds with high J c at low temperatures, but which are degraded severely at temperatures of interest. This problem is associated with thermally activated motion of magnetic flux lines in BSCCO. Reducing these dc losses at higher temperatures will require a high density of microscopic defects that will pin flux lines and inhibit their motion. Recently it was shown that optimum defects can be produced by small tracks formed by passage of energetic heavy ions. Such defects result when Bi is bombarded with high energy protons. The longer range of protons in matter suggests the possibility of application to tape conductors. AC losses are a major limitation in many applications of superconductivity such as power transmission. The improved pinning of flux lines reduces ac losses, but optimization also involves other factors. Measuring and characterizing these losses with respect to material parameters and conductor design is essential to successful development of ac devices

  8. High temperature facility TS-3000 K

    International Nuclear Information System (INIS)

    Ion, M.; Padureanu, I.; Mateescu, G.; Radulescu, G.

    1998-01-01

    The high temperature facility TS-3000 K is designed for inelastic and quasielastic slow neutron scattering and neutron diffraction experiments in condensed matter studies over a very large temperature range. A large class of materials is proposed for such kind of investigations: 1. Investigation of oxygen disorder, thermal parameters, lattice vibrations and elastic constants of nuclear fuel oxides as UO 2 , ThO 2 , PuO 2 at temperatures up to 3000 K; 2. Large and small angle neutron scattering experiments on disordered materials; 3. Investigation of the fast ion conductor lattice dynamics (superionic) using neutron scattering techniques; 4. Structure and dynamics of the liquid metals and alloys both in high purity state and with various impurities; 5. Investigation of the materials for fusion reactors at temperatures up to 3000 K; 6. Neutron - dynamics studies of the carbon lattice, its modifications, as well as fullerenes, at high temperature; 7. High temperature mass spectrometric measurements; 8. High purity materials. The facility TS-3000 is running under high internal vacuum conditions (under 10 -6 mbar), water cooled, automatically controlled and stabilized within a very large temperature range (Tmax = 3000 K) for samples of 80 x 80 mm size for inelastic neutron scattering or of a smaller size for diffraction investigation. The temperature is measured either by a wolfram - 5% Rh thermocouple or by direct viewing IR electronic thermometer. First investigations are planned at high intensity and resolution spectrometric complex DIN-2PI setup at the fast pulsed reactor IBR-2 of the Joint Institute for Nuclear Research, Dubna. The main parts of the TS-3000 K facility are: - The furnace with tungsten heater, tungsten, niobium or tantalum shields positioned in an accurate geometry depending of the temperature range and neutron optics (Tmax=3000 K); - The power supply assembly, data acquisition and storage, automatic or manual control; - The power three

  9. Progress in advanced high temperature materials technology

    Science.gov (United States)

    Freche, J. C.; Ault, G. M.

    1976-01-01

    Materials for intermediate temperature applications are considered, taking into account possibilities regarding the use of prealloyed powder processing to obtain superalloys with increased strength for turbine disk applications. Materials for high temperature application are also discussed. Attention is given to oxide dispersion strengthened alloys (ODS), ceramics, directionally solidified eutectics, ODS + gamma prime alloys, and composites. A description is presented of various approaches for providing environmental protection.

  10. High temperature estimation through computer vision

    International Nuclear Information System (INIS)

    Segovia de los R, J.A.

    1996-01-01

    The form recognition process has between his purposes to conceive and to analyze the classification algorithms applied to the image representations, sounds or signals of any kind. In a process with a thermal plasma reactor in which cannot be employed conventional dispositives or methods for the measurement of the very high temperatures. The goal of this work was to determine these temperatures in an indirect way. (Author)

  11. Raman spectroscopy in high temperature chemistry

    International Nuclear Information System (INIS)

    Drake, M.C.; Rosenblatt, G.M.

    1979-01-01

    Raman spectroscopy (largely because of advances in laser and detector technology) is assuming a rapidly expanding role in many areas of research. This paper reviews the contribution of Raman spectroscopy in high temperature chemistry including molecular spectroscopy on static systems and gas diagnostic measurements on reactive systems. An important aspect of high temperature chemistry has been the identification and study of the new, and often unusual, gaseous molecules which form at high temperatures. Particularly important is the investigation of vibrational-rotational energy levels and electronic states which determine thermodynamic properties and describe chemical bonding. Some advantages and disadvantages of high temperature Raman spectrosocpy for molecular studies on static systems are compared: (1) Raman vs infrared; (2) gas-phase vs condensed in matries; and (3) atmospheric pressure Raman vs low pressure techniques, including mass spectroscopy, matrix isolation, and molecular beams. Raman studies on molecular properties of gases, melts, and surfaces are presented with emphasis on work not covered in previous reviews of high temperature and matrix isolation Raman spectroscopy

  12. High-temperature discrete dislocation plasticity

    Science.gov (United States)

    Keralavarma, S. M.; Benzerga, A. A.

    2015-09-01

    A framework for solving problems of dislocation-mediated plasticity coupled with point-defect diffusion is presented. The dislocations are modeled as line singularities embedded in a linear elastic medium while the point defects are represented by a concentration field as in continuum diffusion theory. Plastic flow arises due to the collective motion of a large number of dislocations. Both conservative (glide) and nonconservative (diffusion-mediated climb) motions are accounted for. Time scale separation is contingent upon the existence of quasi-equilibrium dislocation configurations. A variational principle is used to derive the coupled governing equations for point-defect diffusion and dislocation climb. Superposition is used to obtain the mechanical fields in terms of the infinite-medium discrete dislocation fields and an image field that enforces the boundary conditions while the point-defect concentration is obtained by solving the stress-dependent diffusion equations on the same finite-element grid. Core-level boundary conditions for the concentration field are avoided by invoking an approximate, yet robust kinetic law. Aspects of the formulation are general but its implementation in a simple plane strain model enables the modeling of high-temperature phenomena such as creep, recovery and relaxation in crystalline materials. With emphasis laid on lattice vacancies, the creep response of planar single crystals in simple tension emerges as a natural outcome in the simulations. A large number of boundary-value problem solutions are obtained which depict transitions from diffusional to power-law creep, in keeping with long-standing phenomenological theories of creep. In addition, some unique experimental aspects of creep in small scale specimens are also reproduced in the simulations.

  13. Laser Brazing of High Temperature Braze Alloy

    Science.gov (United States)

    Gao, Y. P.; Seaman, R. F.; McQuillan, T. J.; Martiens, R. F.

    2000-01-01

    the braze materials and tube substrate. Metallography of the laser braze joint was compared to the furnace braze. SEM Energy Disperse X-Ray Spectra (EDX) and back scattered imaging were used to analyze braze alloy segregation. Although all of the laser systems, CO2, ND:YAG, and direct diode laser produced good braze joint, the direct diode laser was selected for its system simplicity, compactness and portability. Excellent laser and braze alloy coupling is observed with powder alloy compared to braze alloy wire. Good wetting is found with different gold based braze alloys. The laser brazing process can be optimized so that the adverse affect on the parent materials can be eliminated. Metallography of the laser braze joint has shown that quality braze joint was produced with laser brazing process. Penetration of the laser braze to the substrate is at neglectable level. Zero penetration is observed. Microstructure examinations shown that no observable changes of the microstructure (grain structure and precipitation) in the HAZ area between laser braze and furnace braze. Wide gaps can be laser brazed with single pass for up to 0.024 inches. Finer dendritic structure is observed in laser brazing compared with equiaxial and coarser grain of the furnace brazing microstructure. Greater segregation is also found in the furnace braze. Higher hardness of the laser braze joint comparing to furnace braze is observed due to the fast cooling rate and Finer microstructure in the laser brazing. Laser braze joint properties meet or exceed the furnace joint properties. Direct diode laser for thin section tube brazing with high temperature braze alloys have been successfully demonstrated. The laser's high energy density and precise control has shown significant advantages in reducing process heat input to the substrates and provide high quality braze joints comparing to other localized braze process such as torch, TIG, and MPTA processes. Significant cost savings can be realized

  14. Quantitative analysis of circadian single cell oscillations in response to temperature.

    Science.gov (United States)

    Abraham, Ute; Schlichting, Julia Katharina; Kramer, Achim; Herzel, Hanspeter

    2018-01-01

    Body temperature rhythms synchronize circadian oscillations in different tissues, depending on the degree of cellular coupling: the responsiveness to temperature is higher when single circadian oscillators are uncoupled. So far, the role of coupling in temperature responsiveness has only been studied in organotypic tissue slices of the central circadian pacemaker, because it has been assumed that peripheral target organs behave like uncoupled multicellular oscillators. Since recent studies indicate that some peripheral tissues may exhibit cellular coupling as well, we asked whether peripheral network dynamics also influence temperature responsiveness. Using a novel technique for long-term, high-resolution bioluminescence imaging of primary cultured cells, exposed to repeated temperature cycles, we were able to quantitatively measure period, phase, and amplitude of central (suprachiasmatic nuclei neuron dispersals) and peripheral (mouse ear fibroblasts) single cell oscillations in response to temperature. Employing temperature cycles of different lengths, and different cell densities, we found that some circadian characteristics appear cell-autonomous, e.g. period responses, while others seem to depend on the quality/degree of cellular communication, e.g. phase relationships, robustness of the oscillation, and amplitude. Overall, our findings indicate a strong dependence on the cell's ability for intercellular communication, which is not only true for neuronal pacemakers, but, importantly, also for cells in peripheral tissues. Hence, they stress the importance of comparative studies that evaluate the degree of coupling in a given tissue, before it may be used effectively as a target for meaningful circadian manipulation.

  15. Strain-induced high-temperature perovskite ferromagnetic insulator.

    Science.gov (United States)

    Meng, Dechao; Guo, Hongli; Cui, Zhangzhang; Ma, Chao; Zhao, Jin; Lu, Jiangbo; Xu, Hui; Wang, Zhicheng; Hu, Xiang; Fu, Zhengping; Peng, Ranran; Guo, Jinghua; Zhai, Xiaofang; Brown, Gail J; Knize, Randy; Lu, Yalin

    2018-03-20

    Ferromagnetic insulators are required for many new magnetic devices, such as dissipationless quantum-spintronic devices, magnetic tunneling junctions, etc. Ferromagnetic insulators with a high Curie temperature and a high-symmetry structure are critical integration with common single-crystalline oxide films or substrates. So far, the commonly used ferromagnetic insulators mostly possess low-symmetry structures associated with a poor growth quality and widespread properties. The few known high-symmetry materials either have extremely low Curie temperatures (≤16 K), or require chemical doping of an otherwise antiferromagnetic matrix. Here we present compelling evidence that the LaCoO 3 single-crystalline thin film under tensile strain is a rare undoped perovskite ferromagnetic insulator with a remarkably high T C of up to 90 K. Both experiments and first-principles calculations demonstrate tensile-strain-induced ferromagnetism which does not exist in bulk LaCoO 3 The ferromagnetism is strongest within a nearly stoichiometric structure, disappearing when the Co 2+ defect concentration reaches about 10%. Significant impact of the research includes demonstration of a strain-induced high-temperature ferromagnetic insulator, successful elevation of the transition over the liquid-nitrogen temperature, and high potential for integration into large-area device fabrication processes. Copyright © 2018 the Author(s). Published by PNAS.

  16. High temperature thrust chamber for spacecraft

    Science.gov (United States)

    Chazen, Melvin L. (Inventor); Mueller, Thomas J. (Inventor); Kruse, William D. (Inventor)

    1998-01-01

    A high temperature thrust chamber for spacecraft (20) is provided herein. The high temperature thrust chamber comprises a hollow body member (12) having an outer surface and an internal surface (16) defining the high temperature chamber (10). The body member (12) is made substantially of rhenium. An alloy (18) consisting of iridium and at least alloying metal selected of the group consisting of rhodium, platinum and palladium is deposited on at least a portion of the internal surface (16) of the body member (12). The iridium and the alloying metal are electrodeposited onto the body member (12). A HIP cycle is performed upon the body member (12) to cause the coating of iridium and the alloying metal to form the alloy (18) which protects the body member (12) from oxidation.

  17. High transition temperature superconducting integrated circuit

    International Nuclear Information System (INIS)

    DiIorio, M.S.

    1985-01-01

    This thesis describes the design and fabrication of the first superconducting integrated circuit capable of operating at over 10K. The primary component of the circuit is a dc SQUID (Superconducting QUantum Interference Device) which is extremely sensitive to magnetic fields. The dc SQUID consists of two superconductor-normal metal-superconductor (SNS) Josephson microbridges that are fabricated using a novel step-edge process which permits the use of high transition temperature superconductors. By utilizing electron-beam lithography in conjunction with ion-beam etching, very small microbridges can be produced. Such microbridges lead to high performance dc SQUIDs with products of the critical current and normal resistance reaching 1 mV at 4.2 K. These SQUIDs have been extensively characterized, and exhibit excellent electrical characteristics over a wide temperature range. In order to couple electrical signals into the SQUID in a practical fashion, a planar input coil was integrated for efficient coupling. A process was developed to incorporate the technologically important high transition temperature superconducting materials, Nb-Sn and Nb-Ge, using integrated circuit techniques. The primary obstacles were presented by the metallurgical idiosyncrasies of the various materials, such as the need to deposit the superconductors at elevated temperatures, 800-900 0 C, in order to achieve a high transition temperature

  18. High temperature superconductivity the road to higher critical temperature

    CERN Document Server

    Uchida, Shin-ichi

    2015-01-01

    This book presents an overview of material-specific factors that influence Tc and give rise to diverse Tc values for copper oxides and iron-based high- Tc superconductors on the basis of more than 25 years of experimental data, to most of which the author has made important contributions. The book then explains why both compounds are distinct from others with similar crystal structure and whether or not one can enhance Tc, which in turn gives a hint on the unresolved pairing mechanism. This is an unprecedented new approach to the problem of high-temperature superconductivity and thus will be inspiring to both specialists and non-specialists interested in this field.   Readers will receive in-depth information on the past, present, and future of high-temperature superconductors, along with special, updated information on what the real highest Tc values are and particularly on the possibility of enhancing Tc for each member material, which is important for application. At this time, the highest Tc has not been...

  19. High temperature getter for compact HID lamps

    Energy Technology Data Exchange (ETDEWEB)

    Maagt, B J de [Central Development Lighting, Philips Lighting B.V., PO Box 80020, 5600JM, Eindhoven (Netherlands); Corazza, A [SAES Getters S.p.A., Viale Italia 77, 20020 Lainate, Milan (Italy)

    2005-09-07

    In high intensity discharge (HID) lamps getters are generally used to remove gaseous impurities that otherwise may have negative effects on the lamp characteristics. Hydrogen, in particular, is a dangerous impurity because it can induce ignition problems and, in lamps with a quartz burner, it can diffuse from the outer bulb into the arc tube and cause early corrosion of the quartz. Recently a new getter, suitable to work in compact HID lamps operated at high temperatures, has been developed: this getter is an appropriate solution to sorb hydrogen at high working temperatures in lamps where the use of a conventional getter is inadequate because of its small capacity for gettering hydrogen, its relatively high hydrogen equilibrium pressure and problems associated with the evaporation of getter and container material. The newly developed getter, named high temperature getter (HTG), is based on a special alloy enclosed in a niobium container. The new alloy is very effective in sorbing hydrogen in the temperature region of 500-900 deg. C. It has been proved that by introducing the HTG the processing of high-wattage compact HID lamps can be simplified and a better lamp performance can be obtained.

  20. High temperature and pressure alkaline electrolysis

    Energy Technology Data Exchange (ETDEWEB)

    Ganley, Jason C. [Department of Chemical Engineering, Howard University, 2013 Lewis K. Downing Hall, 2300 6th Street NW, Washington, DC 20059 (United States)

    2009-05-15

    This paper describes experimental work involving the direct-current electrolysis of highly concentrated potassium hydroxide solutions at high temperatures (up to 400 C) and under various pressures. A high-temperature alkaline electrolysis cell resistant to chemical attack from the highly corrosive electrolyte solution and capable of high-pressure operation was designed and tested. The cell was constructed with a Monel {sup registered} alloy housing and cathode, while various anode materials were compared. The anode materials tested included nickel, Monel alloy, lithiated nickel, and cobalt-plated nickel. The advantages of operating an alkaline electrolysis cell at high temperatures include increasing the ionic conductivity of the electrolyte and enhancing the rates of electrochemical reactions at the electrode surfaces. Cell operation with increasing steam partial pressure over the solution is also shown to enhance cell performance. The prudent selection of anode material also impacts the required terminal potential for a given current density, and consequently the cell's electric power efficiency. The best cell performance was achieved using a cobalt-plated nickel anode at a temperature of 400 C and a steam partial pressure of 8.7 MPa. (author)

  1. Metallic Membranes for High Temperature Hydrogen Separation

    DEFF Research Database (Denmark)

    Ma, Y.H.; Catalano, Jacopo; Guazzone, Federico

    2013-01-01

    Composite palladium membranes have extensively been studied in laboratories and, more recently, in small pilot industrial applications for the high temperature separation of hydrogen from reactant mixtures such as water-gas shift (WGS) reaction or methane steam reforming (MSR). Composite Pd...... than 1000, respectively. This chapter describes in detail composite Pd-based membrane preparation methods, which consist of the grading of the support and the deposition of the dense metal layer, their performances, and their applications in catalytic membrane reactors (CMRs) at high temperatures (400...

  2. Brazing, high temperature brazing and diffusion welding

    International Nuclear Information System (INIS)

    1989-01-01

    Brazing and high temperature brazing is a major joining technology within the economically important fields of energy technology, aerospace and automotive engineering, that play a leading role for technical development everywhere in the world. Moreover diffusion welding has gained a strong position especially in advanced technologies due to its specific advantages. Topics of the conference are: 1. high-temperature brazing in application; 2. basis of brazing technology; 3. brazing of light metals; 4. nondestructive testing; 5. diffusion welding; 6. brazing of hard metals and other hard materials; and 7. ceramic-metal brazing. 28 of 20 lectures and 20 posters were recorded separately for the database ENERGY. (orig./MM) [de

  3. 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

  4. High temperature helical tubular receiver for concentrating solar power system

    Science.gov (United States)

    Hossain, Nazmul

    In the field of conventional cleaner power generation technology, concentrating solar power systems have introduced remarkable opportunity. In a solar power tower, solar energy concentrated by the heliostats at a single point produces very high temperature. Falling solid particles or heat transfer fluid passing through that high temperature region absorbs heat to generate electricity. Increasing the residence time will result in more heat gain and increase efficiency. A novel design of solar receiver for both fluid and solid particle is approached in this paper which can increase residence time resulting in higher temperature gain in one cycle compared to conventional receivers. The helical tubular solar receiver placed at the focused sunlight region meets the higher outlet temperature and efficiency. A vertical tubular receiver is modeled and analyzed for single phase flow with molten salt as heat transfer fluid and alloy625 as heat transfer material. The result is compared to a journal paper of similar numerical and experimental setup for validating our modeling. New types of helical tubular solar receivers are modeled and analyzed with heat transfer fluid turbulent flow in single phase, and granular particle and air plug flow in multiphase to observe the temperature rise in one cyclic operation. The Discrete Ordinate radiation model is used for numerical analysis with simulation software Ansys Fluent 15.0. The Eulerian granular multiphase model is used for multiphase flow. Applying the same modeling parameters and boundary conditions, the results of vertical and helical receivers are compared. With a helical receiver, higher temperature gain of heat transfer fluid is achieved in one cycle for both single phase and multiphase flow compared to the vertical receiver. Performance is also observed by varying dimension of helical receiver.

  5. High-Temperature Shape Memory Polymers

    Science.gov (United States)

    Yoonessi, Mitra; Weiss, Robert A.

    2012-01-01

    physical conformation changes when exposed to an external stimulus, such as a change in temperature. Such materials have a permanent shape, but can be reshaped above a critical temperature and fixed into a temporary shape when cooled under stress to below the critical temperature. When reheated above the critical temperature (Tc, also sometimes called the triggering or switching temperature), the materials revert to the permanent shape. The current innovation involves a chemically treated (sulfonated, carboxylated, phosphonated, or other polar function group), high-temperature, semicrystalline thermoplastic poly(ether ether ketone) (Tg .140 C, Tm = 340 C) mix containing organometallic complexes (Zn++, Li+, or other metal, ammonium, or phosphonium salts), or high-temperature ionic liquids (e.g. hexafluorosilicate salt with 1-propyl-3- methyl imidazolium, Tm = 210 C) to form a network where dipolar or ionic interactions between the polymer and the low-molecular-weight or inorganic compound forms a complex that provides a physical crosslink. Hereafter, these compounds will be referred to as "additives". The polymer is semicrystalline, and the high-melt-point crystals provide a temporary crosslink that acts as a permanent crosslink just so long as the melting temperature is not exceeded. In this example case, the melting point is .340 C, and the shape memory critical temperature is between 150 and 250 C. PEEK is an engineering thermoplastic with a high Young fs modulus, nominally 3.6 GPa. An important aspect of the invention is the control of the PEEK functionalization (in this example, the sulfonation degree), and the thermal properties (i.e. melting point) of the additive, which determines the switching temperature. Because the compound is thermoplastic, it can be formed into the "permanent" shape by conventional plastics processing operations. In addition, the compound may be covalently cross - linked after forming the permanent shape by S-PEEK by applying ionizing

  6. Measuring nanowire thermal conductivity at high temperatures

    Science.gov (United States)

    Wang, Xiaomeng; Yang, Juekuan; Xiong, Yucheng; Huang, Baoling; Xu, Terry T.; Li, Deyu; Xu, Dongyan

    2018-02-01

    This work extends the micro-thermal-bridge method for thermal conductivity measurements of nanowires to high temperatures. The thermal-bridge method, based on a microfabricated device with two side-by-side suspended membranes with integrated platinum resistance heaters/thermometers, has been used to determine thermal conductivity of various nanowires/nanotubes/nanoribbons at relatively low temperatures. However, to date, thermal conductivity characterization of nanowires at temperatures above 600 K has seldom been reported presumably due to several technical difficulties including the instability of the microfabricated thermometers, radiation heat loss, and the effect of the background conductance on the measurement. Here we report on our attempt to address the aforementioned challenges and demonstrate thermal conductivity measurement of boron nanoribbons up to 740 K. To eliminate high temperature resistance instability, the device is first annealed at 1023 K for 5 min in an argon atmosphere. Two radiation shields are installed in the measurement chamber to minimize radiation heat loss from the measurement device to the surroundings; and the temperature of the device at each set point is calibrated by an additional thermocouple directly mounted on the chip carrier. The effect of the background conductance is eliminated by adopting a differential measurement scheme. With all these modifications, we successfully measured the thermal conductivity of boron nanoribbons over a wide temperature range from 27 K to 740 K. The measured thermal conductivity increases monotonically with temperature and reaches a plateau of ~2.5 W m‑1 K‑1 at approximately 400 K, with no clear signature of Umklapp scattering observed in the whole measurement temperature range.

  7. Helium diffusion in nickel at high temperatures

    International Nuclear Information System (INIS)

    Philipps, V.

    1980-09-01

    Helium has been implanted at certain temperatures between 800 and 1250 0 C into single and polycrystalline Ni-samples with implantation depths between 15 and 90 μm. Simultaneously the helium reemission from the sample is measured by a mass-spectrometer. It has been shown that the time dependence of the observed reemission rate is governed by volume diffusion of the helium. Measuring this time dependence as a function of temperature the helium diffusion constant has been determined. The He-diffusion is interpreted as a interstitial diffusion hindered by thermal vacancies. Depending on the implantation depth more or less of the implanted helium remains in the sample and forms large helium bubbles. (orig./GSCH)

  8. Bimodular high temperature planar oxygen gas sensor

    Science.gov (United States)

    Sun, Xiangcheng; Liu, Yixin; Gao, Haiyong; Gao, Puxian; Lei, Yu

    2014-08-01

    A bimodular planar O2 sensor was fabricated using NiO nanoparticles (NPs) thin film coated yttria-stabilized zirconia (YSZ) substrate. The thin film was prepared by radio frequency (r.f.) magnetron sputtering of NiO on YSZ substrate, followed by high temperature sintering. The surface morphology of NiO nanoparticles film was characterized by atomic force microscopy (AFM) and scanning electron microscopy (SEM). X-ray diffraction (XRD) patterns of NiO NPs thin film before and after high temperature O2 sensing demonstrated that the sensing material possesses a good chemical and structure stability. The oxygen detection experiments were performed at 500 °C, 600 °C and 800 °C using the as-prepared bimodular O2 sensor under both potentiometric and resistance modules. For the potentiometric module, a linear relationship between electromotive force (EMF) output of the sensor and the logarithm of O2 concentration was observed at each operating temperature, following the Nernst law. For the resistance module, the logarithm of electrical conductivity was proportional to the logarithm of oxygen concentration at each operating temperature, in good agreement with literature report. In addition, this bimodular sensor shows sensitive, reproducible and reversible response to oxygen under both sensing modules. Integration of two sensing modules into one sensor could greatly enrich the information output and would open a new venue in the development of high temperature gas sensors.

  9. Bimodular high temperature planar oxygen gas sensor

    Directory of Open Access Journals (Sweden)

    Xiangcheng eSun

    2014-08-01

    Full Text Available A bimodular planar O2 sensor was fabricated using NiO nanoparticles (NPs thin film coated yttria-stabilized zirconia (YSZ substrate. The thin film was prepared by radio frequency (r.f. magnetron sputtering of NiO on YSZ substrate, followed by high temperature sintering. The surface morphology of NiO nanoparticles film was characterized by atomic force microscopy (AFM and scanning electron microscopy (SEM. X-ray diffraction (XRD patterns of NiO NPs thin film before and after high temperature O2 sensing demonstrated that the sensing material possesses a good chemical and structure stability. The oxygen detection experiments were performed at 500 °C, 600 °C and 800 °C using the as-prepared bimodular O2 sensor under both potentiometric and resistance modules. For the potentiometric module, a linear relationship between electromotive force (EMF output of the sensor and the logarithm of O2 concentration was observed at each operating temperature, following the Nernst law. For the resistance module, the logarithm of electrical conductivity was proportional to the logarithm of oxygen concentration at each operating temperature, in good agreement with literature report. In addition, this bimodular sensor shows sensitive, reproducible and reversible response to oxygen under both sensing modules. Integration of two sensing modules into one sensor could greatly enrich the information output and would open a new venue in the development of high temperature gas sensors.

  10. A high temperature high pressure cell for quasielastic neutron scattering.

    Science.gov (United States)

    Yang, F; Kaplonski, J; Unruh, T; Mamontov, E; Meyer, A

    2011-08-01

    We present our recent development of a high temperature high pressure cell for neutron scattering. Combining a water cooled Nb1Zr pressure cell body with an internal heating furnace, the sample environment can reach temperatures of up to 1500 K at a pressure of up to 200 MPa at the sample position, with an available sample volume of about 700 mm(3). The cell material Nb1Zr is specifically chosen due to its reasonable mechanical strength at elevated temperatures and fairly small neutron absorption and incoherent scattering cross sections. With this design, an acceptable signal-to-noise ratio of about 10:1 can be achieved. This opens new possibilities for quasielastic neutron scattering studies on different types of neutron spectrometers under high temperature high pressure conditions, which is particularly interesting for geological research on, e.g., water dynamics in silicate melts.

  11. HYFIRE: fusion-high temperature electrolysis system

    International Nuclear Information System (INIS)

    Fillo, J.A.; Powell, J.R.; Steinberg, M.; Benenati, R.; Dang, V.D.; Horn, F.; Isaacs, H.; Lazareth, O.; Makowitz, H.; Usher, J.

    1980-01-01

    The Brookhaven National Laboratory (BNL) is carrying out a comprehensive conceptual design study called HYFIRE of a commercial fusion Tokamak reactor, high-temperature electrolysis system. The study is placing particular emphasis on the adaptability of the STARFIRE power reactor to a synfuel application. The HYFIRE blanket must perform three functions: (a) provide high-temperature (approx. 1400 0 C) process steam at moderate pressures (in the range of 10 to 30 atm) to the high-temperature electrolysis (HTE) units; (b) provide high-temperature (approx. 700 to 800 0 C) heat to a thermal power cycle for generation of electricity to the HTE units; and (c) breed enough tritium to sustain the D-T fuel cycle. In addition to thermal energy for the decomposition of steam into its constitutents, H 2 and O 2 , electrical input is required. Power cycle efficiencies of approx. 40% require He cooling for steam superheat. Fourteen hundred degree steam coupled with 40% power cycle efficiency results in a process efficiency (conversion of fusion energy to hydrogen chemical energy) of 50%

  12. Potential applications of high temperature helium

    International Nuclear Information System (INIS)

    Schleicher, R.W. Jr.; Kennedy, A.J.

    1992-09-01

    This paper discusses the DOE MHTGR-SC program's recent activity to improve the economics of the MHTGR without sacrificing safety performance and two potential applications of high temperature helium, the MHTGR gas turbine plant and a process heat application for methanol production from coal

  13. High temperature fatigue behaviour of intermetallics

    Indian Academy of Sciences (India)

    There would be considerable benefits in developing new structural materials where high use temperatures and strength coupled with low density are minimum capabilities. Nickel and titanium aluminides exhibit considerable potential for near-term application in various branches of modern industry due to the number of ...

  14. High temperature impedance spectroscopy of barium stannate ...

    Indian Academy of Sciences (India)

    High temperature impedance spectroscopy of barium stannate, BaSnO3. SHAIL UPADHYAY. Department of Physics, Institute of Technology, Banaras Hindu University, Varanasi 221 005, India. MS received 29 May 2012; revised 14 July 2012. Abstract. Polycrystalline powder of BaSnO3 was prepared at 1300 ◦C using a ...

  15. High temperature applications of nuclear energy

    International Nuclear Information System (INIS)

    1994-08-01

    The meeting was organized to review industry/user needs designs, status of technology and the associated economics for high temperature applications. It was attended by approximately 100 participants from nine countries. The participants presented 17 papers. A separate abstract was prepared for each of these papers. Refs, figs and tabs

  16. High temperatures influence sexual development differentially in ...

    Indian Academy of Sciences (India)

    Although sex determination in amphibians is believed to be a genetic process, environmental factors such as temperatureare known to influence the sex differentiation and development. Extremely low and high temperatures influence gonadaldevelopment and sex ratio in amphibians but the mechanism of action is not ...

  17. Theory of high temperature plasmas. Final report

    International Nuclear Information System (INIS)

    Davidson, R.C.; Liu, C.S.

    1977-01-01

    This is a report on the technical progress in our analytic studies of high-temperature fusion plasmas. We also emphasize that the research summarized here makes extensive use of computational methods and therefore forms a strong interface with our numerical modeling program which is discussed later in the report

  18. Thermoelastic properties of minerals at high temperature

    Indian Academy of Sciences (India)

    The knowledge of elasticity of the minerals is useful for interpreting the structure and composition of the lower mantle and also in seismic studies. The purpose of the present study is to discuss a simple and straightforward method for evaluating thermoelastic properties of minerals at high temperatures. We have extended ...

  19. High-pressure-high-temperature treatment of natural diamonds

    CERN Document Server

    Royen, J V

    2002-01-01

    The results are reported of high-pressure-high-temperature (HPHT) treatment experiments on natural diamonds of different origins and with different impurity contents. The diamonds are annealed in a temperature range up to 2000 sup o C at stabilizing pressures up to 7 GPa. The evolution is studied of different defects in the diamond crystal lattice. The influence of substitutional nitrogen atoms, plastic deformation and the combination of these is discussed. Diamonds are characterized at room and liquid nitrogen temperature using UV-visible spectrophotometry, Fourier transform infrared spectrophotometry and photoluminescence spectrometry. The economic implications of diamond HPHT treatments are discussed.

  20. The Lifetime Estimate for ACSR Single-Stage Splice Connector Operating at Higher Temperatures

    International Nuclear Information System (INIS)

    Wang, Jy-An John; Graziano, Joe; Chan, John

    2011-01-01

    This paper is the continuation of Part I effort to develop a protocol of integrating analytical and experimental approaches to evaluate the integrity of a full tension single-stage splice connector (SSC) assembly during service at high operating temperature.1The Part II efforts are mainly focused on the thermal mechanical testing, thermal-cycling simulation and its impact on the effective lifetime of the SSC system. The investigation indicates that thermal cycling temperature and frequency, conductor cable tension loading, and the compressive residual stress field within a SSC system have significant impact on the SSC integrity and the associated effective lifetime.

  1. A two-axis goniometer for low-temperature nuclear magnetic resonance measurements on single crystals.

    Science.gov (United States)

    Shiroka, T; Casola, F; Mesot, J; Bachmann, W; Ott, H-R

    2012-09-01

    We report on the construction of a two-axis goniometer intended for low-temperature, single-crystal nuclear magnetic resonance (NMR) measurements. With the use of home-made and commercially available parts, our simple probe-head design achieves good sensitivity, while maintaining a high angular precision and the ability to orient samples also when cooled to liquid helium temperatures. The probe with the goniometer is adapted to be inserted into a commercial (4)He-flow cryostat, which fits into a wide-bore superconducting solenoid magnet. Selected examples of NMR measurements illustrate the operation of the device.

  2. The Evolution of High Temperature Gas Sensors.

    Energy Technology Data Exchange (ETDEWEB)

    Garzon, F. H. (Fernando H.); Brosha, E. L. (Eric L.); Mukundan, R. (Rangachary)

    2001-01-01

    Gas sensor technology based on high temperature solid electrolytes is maturing rapidly. Recent advances in metal oxide catalysis and thin film materials science has enabled the design of new electrochemical sensors. We have demonstrated prototype amperometric oxygen sensors, nernstian potentiometric oxygen sensors that operate in high sulfur environments, and hydrocarbon and carbon monoxide sensing mixed potentials sensors. Many of these devices exhibit part per million sensitivities, response times on the order of seconds and excellent long-term stability.

  3. A high temperature reactor for ship propulsion

    International Nuclear Information System (INIS)

    Lobet, P.; Seigel, R.; Thompson, A.C.; Beadnell, R.M.; Beeley, P.A.

    2002-01-01

    The initial thermal hydraulic and physics design of a high temperature gas cooled reactor for ship propulsion is described. The choice of thermodynamic cycle and thermal power is made to suit the marine application. Several configurations of a Helium cooled, Graphite moderated reactor are then analysed using the WIMS and MONK codes from AEA Technology. Two geometries of fuel elements formed using micro spheres in prismatic blocks, and various arrangements of control rods and poison rods are examined. Reactivity calculations through life are made and a pattern of rod insertion to flatten the flux is proposed and analysed. Thermal hydraulic calculations are made to find maximum fuel temperature under high power with optimized flow distribution. Maximum temperature after loss of flow and temperatures in the reactor vessel are also computed. The temperatures are significantly below the known limits for the type of fuel proposed. It is concluded that the reactor can provide the required power and lifetime between refueling within likely space and weight constraints. (author)

  4. High temperature intermetallic binders for HVOF carbides

    International Nuclear Information System (INIS)

    Shaw, K.G.; Gruninger, M.F.; Jarosinski, W.J.

    1994-01-01

    Gas turbines technology has a long history of employing the desirable high temperature physical attributes of ceramic-metallic (cermet) materials. The most commonly used coatings incorporate combinations of WC-Co and Cr 3 C 2 -NiCr, which have also been successfully utilized in other non-turbine coating applications. Increased turbine operating temperatures and other high temperature service conditions have made apparent the attractive notion of increasing the temperature capability and corrosion resistance of these coatings. In this study the intermetallic binder NiAl has been used to replace the cobalt and NiCr constituents of conventional WC and Cr 3 C 2 cermet powders. The composite carbide thermal spray powders were fabricated for use in the HVOF coating process. The structure of HVOF deposited NiAl-carbide coatings are compared directly to the more familiar WC-Co and Cr 3 C 2 -NiCr coatings using X-ray diffraction, back-scattered electron imaging (BEI) and electron dispersive spectroscopy (EDS). Hardness variations with temperature are reported and compared between the NiAl and Co/NiCr binders

  5. High temperature 3D QCD: dimensional reduction at work

    Science.gov (United States)

    Bialas, P.; Morel, A.; Petersson, B.; Petrov, K.; Reisz, T.

    2000-08-01

    We investigate the three-dimensional SU(3) gauge theory at finite temperature in the framework of dimensional reduction. The large scale properties of this theory are expected to be conceptually more complicated than in four dimensions. The dimensionally reduced action is computed in closed analytical form. The resulting effective two-dimensional theory is studied numerically both in the electric and magnetic sector. We find that dimensional reduction works excellently down to temperatures of 1.5 times the deconfinement phase transition temperature and even on rather short length scales. We obtain strong evidence that for QCD 3, even at high temperature the colour averaged potential is represented by the exchange of a single state, at variance with the usual Debye screening picture involving a pair of electric gluons.

  6. High temperature superconductors applications in telecommunications

    International Nuclear Information System (INIS)

    Kumar, A.A.; Li, J.; Zhang, M.F.

    1994-01-01

    The purpose of this paper is twofold: to discuss high temperature superconductors with specific reference to their employment in telecommunications applications; and to discuss a few of the limitations of the normally employed two-fluid model. While the debate on the actual usage of high temperature superconductors in the design of electronic and telecommunications devices-obvious advantages versus practical difficulties-needs to be settled in the near future, it is of great interest to investigate the parameters and the assumptions that will be employed in such designs. This paper deals with the issue of providing the microwave design engineer with performance data for such superconducting waveguides. The values of conductivity and surface resistance, which are the primary determining factors of a waveguide performance, are computed based on the two-fluid model. A comparison between two models-a theoretical one in terms of microscopic parameters (termed Model A) and an experimental fit in terms of macroscopic parameters (termed Model B)-shows the limitations and the resulting ambiguities of the two-fluid model at high frequencies and at temperatures close to the transition temperature. The validity of the two-fluid model is then discussed. Our preliminary results show that the electrical transport description in the normal and superconducting phases as they are formulated in the two-fluid model needs to be modified to incorporate the new and special features of high temperature superconductors. Parameters describing the waveguide performance-conductivity, surface resistance and attenuation constant-will be computed. Potential applications in communications networks and large scale integrated circuits will be discussed. Some of the ongoing work will be reported. In particular, a brief proposal is made to investigate of the effects of electromagnetic interference and the concomitant notion of electromagnetic compatibility (EMI/EMC) of high T c superconductors

  7. Flux-flow resistivity of three high-temperature superconductors

    International Nuclear Information System (INIS)

    Cha, Y.S.; Evans, D.J.; Hull, J.R.; Seol, S.Y.

    1996-01-01

    Results of experiments on flux-flow resistivity (the relationship of voltage to current) of three high-temperature superconductors are described. The superconductors are a melt-cast BSCCO 2212 rod, a single filament BSCCO powder-in-tube (PIT) tape, and a multifilament PIT tape. The flux-flow resistivity of these superconductors was measured at three temperatures: 77 K (saturated liquid nitrogen), 87 K (saturated liquid argon), and 67 K (subcooled liquid nitrogen). Implications of the present results for practical applications are discussed

  8. Low-temperature phonoemissive tunneling rates in single molecule magnets

    Science.gov (United States)

    Liu, Yun; Garg, Anupam

    2016-03-01

    Tunneling between the two lowest energy levels of single molecule magnets with Ising type anisotropy, accompanied by the emission or absorption of phonons, is considered. Quantitatively accurate calculations of the rates for such tunneling are performed for a model Hamiltonian especially relevant to the best studied example, Fe8. Two different methods are used: high-order perturbation theory in the spin-phonon interaction and the non-Ising-symmetric parts of the spin Hamiltonian, and a novel semiclassical approach based on spin-coherent-state-path-integral instantons. The methods are found to be in good quantitative agreement with other, and consistent with previous approaches to the problem. The implications of these results for magnetization of molecular solids of these molecules are discussed briefly.

  9. Sodium immersible high temperature microphone design description

    International Nuclear Information System (INIS)

    Gavin, A.P.; Anderson, T.T.; Janicek, J.J.

    1975-02-01

    Argonne National Laboratory has developed a rugged high-temperature (HT) microphone for use as a sodium-immersed acoustic monitor in Liquid Metal Fast Breeder Reactors (LMFBRs). Microphones of this design have been extensively tested in room temperature water, in air up to 1200 0 F, and in sodium up to 1200 0 F. They have been successfully installed and employed as acoustic monitors in several operating liquid metal systems. The design, construction sequence, calibration, and testing of these microphones are described. 6 references. (U.S.)

  10. Fracture Studies of High Temperature Ceramics.

    Science.gov (United States)

    1980-05-01

    silicon nitride materials containing HgO, CeO2 or ZrO2 sinterinS aids showed a decrease in 1ZC as the temperature exceeded 13000 C. Hlot- pressed silicon...merization of the furfuryl alcohol was subsequently allowed to proceed at 150°C. Alternatively, slurries of 30 volt SiC were cast, polymerized and pyrolized...shown that the densifying agent (MgO, Y2 03 , CeO2 , A120 3 , etc.) used in hot-pressing dramatically affects the high temperature strength proper

  11. The metallurgy of high temperature alloys

    Science.gov (United States)

    Tien, J. K.; Purushothaman, S.

    1976-01-01

    Nickel-base, cobalt-base, and high nickel and chromium iron-base alloys are dissected, and their microstructural and chemical components are assessed with respect to the various functions expected of high temperature structural materials. These functions include the maintenance of mechanical integrity over the strain-rate spectrum from creep resistance through fatigue crack growth resistance, and such alloy stability expectations as microstructural coarsening resistance, phase instability resistance and oxidation and corrosion resistance. Special attention will be given to the perennial conflict and trade-off between strength, ductility and corrosion and oxidation resistance. The newest developments in the constitution of high temperature alloys will also be discussed, including aspects relating to materials conservation.

  12. Inelastic X-ray scattering experiments at extreme conditions: high temperatures and high pressures

    Directory of Open Access Journals (Sweden)

    S.Hosokawa

    2008-03-01

    Full Text Available In this article, we review the present status of experimental techniques under extreme conditions of high temperature and high pressure used for inelastic X-ray scattering (IXS experiments of liquid metals, semiconductors, molten salts, molecular liquids, and supercritical water and methanol. For high temperature experiments, some types of single-crystal sapphire cells were designed depending on the temperature of interest and the sample thickness for the X-ray transmission. Single-crystal diamond X-ray windows attached to the externally heated high-pressure vessel were used for the IXS experiment of supercritical water and methanol. Some typical experimental results are also given, and the perspective of IXS technique under extreme conditions is discussed.

  13. High Temperature Fluoride Salt Test Loop

    Energy Technology Data Exchange (ETDEWEB)

    Aaron, Adam M. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Cunningham, Richard Burns [Univ. of Tennessee, Knoxville, TN (United States); Fugate, David L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Holcomb, David Eugene [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kisner, Roger A. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Peretz, Fred J. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Robb, Kevin R. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Wilson, Dane F. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Yoder, Jr, Graydon L. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-12-01

    Effective high-temperature thermal energy exchange and delivery at temperatures over 600°C has the potential of significant impact by reducing both the capital and operating cost of energy conversion and transport systems. It is one of the key technologies necessary for efficient hydrogen production and could potentially enhance efficiencies of high-temperature solar systems. Today, there are no standard commercially available high-performance heat transfer fluids above 600°C. High pressures associated with water and gaseous coolants (such as helium) at elevated temperatures impose limiting design conditions for the materials in most energy systems. Liquid salts offer high-temperature capabilities at low vapor pressures, good heat transport properties, and reasonable costs and are therefore leading candidate fluids for next-generation energy production. Liquid-fluoride-salt-cooled, graphite-moderated reactors, referred to as Fluoride Salt Reactors (FHRs), are specifically designed to exploit the excellent heat transfer properties of liquid fluoride salts while maximizing their thermal efficiency and minimizing cost. The FHR s outstanding heat transfer properties, combined with its fully passive safety, make this reactor the most technologically desirable nuclear power reactor class for next-generation energy production. Multiple FHR designs are presently being considered. These range from the Pebble Bed Advanced High Temperature Reactor (PB-AHTR) [1] design originally developed by UC-Berkeley to the Small Advanced High-Temperature Reactor (SmAHTR) and the large scale FHR both being developed at ORNL [2]. The value of high-temperature, molten-salt-cooled reactors is also recognized internationally, and Czechoslovakia, France, India, and China all have salt-cooled reactor development under way. The liquid salt experiment presently being developed uses the PB-AHTR as its focus. One core design of the PB-AHTR features multiple 20 cm diameter, 3.2 m long fuel channels

  14. High temperature superconductivity and cold fusion

    International Nuclear Information System (INIS)

    Rabinowitz, M.

    1990-01-01

    There are numerous historical and scientific parallels between high temperature superconductivity (HTSC) and the newly emerging field of cold fusion (CF). Just as the charge carrier effective mass plays an important role in SC, the deuteron effective mass may play a vital role in CF. A new theory including effects of proximity, electron shielding, and decreased effective mass of the fusing nuclei can account for the reported CF results. A quantum-gas model that covers the range from low temperature to superhigh temperature SC indicates an increased T c with reduced dimensionality. A reduced dimensionality effect may also enhance CF. A relation is shown between CF and the significant cluster-impact fusion experiments

  15. Strain sensing technology for high temperature applications

    Science.gov (United States)

    Williams, W. Dan

    1993-01-01

    This review discusses the status of strain sensing technology for high temperature applications. Technologies covered are those supported by NASA such as required for applications in hypersonic vehicles and engines, advanced subsonic engines, as well as material and structure development. The applications may be at temperatures of 540 C (1000 F) to temperatures in excess of 1400 C (2500 F). The most promising technologies at present are the resistance strain gage and remote sensing schemes. Resistance strain gages discussed include the BCL gage, the LaRC compensated gage, and the PdCr gage. Remote sensing schemes such as laser based speckle strain measurement, phase-shifling interferometry, and x-ray extensometry are discussed. Present status and limitations of these technologies are presented.

  16. Toroidal microinstability studies of high temperature tokamaks

    International Nuclear Information System (INIS)

    Rewoldt, G.; Tang, W.M.

    1989-07-01

    Results from comprehensive kinetic microinstability calculations are presented showing the effects of toroidicity on the ion temperature gradient mode and its relationship to the trapped-electron mode in high-temperature tokamak plasmas. The corresponding particle and energy fluxes have also been computed. It is found that, although drift-type microinstabilities persist over a wide range of values of the ion temperature gradient parameter η i ≡ (dlnT i /dr)/(dlnn i /dr), the characteristic features of the dominant mode are those of the η i -type instability when η i > η ic ∼1.2 to 1.4 and of the trapped-electron mode when η i ic . 16 refs., 7 figs

  17. Optical Fiber Strain Instrumentation for High Temperature Aerospace Structural Monitoring

    Science.gov (United States)

    Wang, A.

    2002-01-01

    The objective of the program is the development and laboratory demonstration of sensors based on silica optical fibers for measurement of high temperature strain for aerospace materials evaluations. A complete fiber strain sensor system based on white-light interferometry was designed and implemented. An experiment set-up was constructed to permit testing of strain measurement up to 850 C. The strain is created by bending an alumina cantilever beam to which is the fiber sensor is attached. The strain calibration is provided by the application of known beam deflections. To ensure the high temperature operation capability of the sensor, gold-coated single-mode fiber is used. Moreover, a new method of sensor surface attachment which permits accurate sensor gage length determination is also developed. Excellent results were obtained at temperatures up to 800-850 C.

  18. Gasification of high ash, high ash fusion temperature bituminous coals

    Science.gov (United States)

    Liu, Guohai; Vimalchand, Pannalal; Peng, WanWang

    2015-11-13

    This invention relates to gasification of high ash bituminous coals that have high ash fusion temperatures. The ash content can be in 15 to 45 weight percent range and ash fusion temperatures can be in 1150.degree. C. to 1500.degree. C. range as well as in excess of 1500.degree. C. In a preferred embodiment, such coals are dealt with a two stage gasification process--a relatively low temperature primary gasification step in a circulating fluidized bed transport gasifier followed by a high temperature partial oxidation step of residual char carbon and small quantities of tar. The system to process such coals further includes an internally circulating fluidized bed to effectively cool the high temperature syngas with the aid of an inert media and without the syngas contacting the heat transfer surfaces. A cyclone downstream of the syngas cooler, operating at relatively low temperatures, effectively reduces loading to a dust filtration unit. Nearly dust- and tar-free syngas for chemicals production or power generation and with over 90%, and preferably over about 98%, overall carbon conversion can be achieved with the preferred process, apparatus and methods outlined in this invention.

  19. High temperature strain of metals and alloys. Physical fundamentals

    Energy Technology Data Exchange (ETDEWEB)

    Levitin, V. [National Technical Univ., Zaporozhye (Ukraine)

    2006-07-01

    The author shows how new in-situ X-ray investigations and transmission electron microscope studies lead to novel explanations of high-temperature deformation and creep in pure metals, solid solutions and super alloys. This approach is the first to find unequivocal and quantitative expressions for the macroscopic deformation rate by means of three groups of parameters: substructural characteristics, physical material constants and external conditions. Creep strength of the studied uptodate single crystal super alloys is greatly increased over conventional polycrystalline super alloys. The contents of this book include: macroscopic characteristics of strain at high temperatures; experimental equipment and technique of in situ X-ray investigations; experimental data and structural parameters in deformed metals; sub-boundaries as dislocation sources and obstacles; the physical mechanism of creep and the quantitative structural model; simulation of the parameters evolution; system of differential equations; high-temperature deformation of industrial super alloys; single crystals of super alloys; effect of composition, orientation and temperature on properties; and creep of some refractory metals.

  20. Quench in high temperature superconductor magnets

    CERN Document Server

    Schwartz, J.

    2013-01-01

    High field superconducting magnets using high temperature superconductors are being developed for high energy physics, nuclear magnetic resonance and energy storage applications. Although the conductor technology has progressed to the point where such large magnets can be readily envisioned, quench protection remains a key challenge. It is well-established that quench propagation in HTS magnets is very slow and this brings new challenges that must be addressed. In this paper, these challenges are discussed and potential solutions, driven by new technologies such as optical fiber based sensors and thermally conducting electrical insulators, are reviewed.

  1. High-Temperature Piezoelectric Ceramic Developed

    Science.gov (United States)

    Sayir, Ali; Farmer, Serene C.; Dynys, Frederick W.

    2005-01-01

    Active combustion control of spatial and temporal variations in the local fuel-to-air ratio is of considerable interest for suppressing combustion instabilities in lean gas turbine combustors and, thereby, achieving lower NOx levels. The actuator for fuel modulation in gas turbine combustors must meet several requirements: (1) bandwidth capability of 1000 Hz, (2) operating temperature compatible with the fuel temperature, which is in the vicinity of 400 F, (3) stroke of approximately 4 mils (100 m), and (4) force of 300 lb-force. Piezoelectric actuators offer the fastest response time (microsecond time constants) and can generate forces in excess of 2000 lb-force. The state-of-the-art piezoceramic material in industry today is Pb(Zr,Ti)O3, called PZT. This class of piezoelectric ceramic is currently used in diesel fuel injectors and in the development of high-response fuel modulation valves. PZT materials are generally limited to operating temperatures of 250 F, which is 150 F lower than the desired operating temperature for gas turbine combustor fuel-modulation injection valves. Thus, there is a clear need to increase the operating temperature range of piezoceramic devices for active combustion control in gas turbine engines.

  2. Energy storage via high temperature superconductivity (SMES)

    Energy Technology Data Exchange (ETDEWEB)

    Mikkonen, R. [Tampere Univ. of Technology (Finland)

    1998-10-01

    The technology concerning high temperature superconductors (HTS) is matured to enabling different kind of prototype applications including SMES. Nowadays when speaking about HTS systems, attention is focused on the operating temperature of 20-30 K, where the critical current and flux density are fairly close to 4.2 K values. In addition by defining the ratio of the energy content of a novel HTS magnetic system and the required power to keep the system at the desired temperature, the optimum settles to the above mentioned temperature range. In the frame of these viewpoints a 5 kJ HTS SMES system has been designed and tested at Tampere University of Technology with a coil manufactured by American Superconductor (AMSC). The HTS magnet has inside and outside diameters of 252 mm and 317 mm, respectively and axial length of 66 mm. It operates at 160 A and carries a total of 160 kA-turns to store the required amount of energy. The effective magnetic inductance is 0.4 H and the peak axial field is 1.7 T. The magnet is cooled to the operating temperature of 20 K with a two stage Gifford-McMahon type cryocooler with a cooling power of 60 W at 77 K and 8 W at 20 K. The magnetic system has been demonstrated to compensate a short term loss of power of a sensitive consumer

  3. Deformation of high-temperature superconductors

    International Nuclear Information System (INIS)

    Goretta, K.C.; Routbort, J.L.; Miller, D.J.; Chen, N.; Dominguez-Rodriguez, A.; Jimenez-Melendo, M.; De Arellano-Lopez, A.R.

    1994-08-01

    Of the many families of high-temperature superconductors, only the properties of those discovered prior to 1989 - Y-Ba-Cu-O, Tl-Ba(Sr)-Ca-Cu-O, and Bi(Pb)-Sr-Ca-Cu-O - have been studied extensively. Deformation tests have been performed on YBa 2 Cu 3 O x (Y-123), YBa 2 Cu 4 O x (Y-124), TlBa 2 Ca 2 Cu 3 O x (Bi-2223). The tests have revealed that plasticity is generally limited in these compounds and that the rate-controlling diffusional kinetics for creep are very slow. Nevertheless, hot forming has proved to be quite successful for fabrication of bulk high-temperature superconductors, so long as deformation rates are low or large hydrostatic stresses are applied. Steady-state creep data have proved to be useful in designing optimal heat treatments for superconductors and in support of more-fundamental diffusion experiments. The high-temperature superconductors are highly complex oxides, and it is a challenge to understand their deformation responses. In this paper, results of interest and operant creep mechanisms will be reviewed

  4. Modeling and off-design performance of a 1 kWe HT-PEMFC (high temperature-proton exchange membrane fuel cell)-based residential micro-CHP (combined-heat-and-power) system for Danish single-family households

    DEFF Research Database (Denmark)

    Arsalis, Alexandros; Nielsen, Mads Pagh; Kær, Søren Knudsen

    2011-01-01

    temperatures, as compared to Nafion-based PEMFCs and therefore can be a significant candidate for cogeneration residential systems. The proposed system can provide electric power, hot water, and space heating for a typical Danish single-family household. A complete fuel processing subsystem, with all necessary......A novel proposal for the modeling and operation of a micro-CHP (combined-heat-and-power) residential system based on HT-PEMFC (High Temperature-Proton Exchange Membrane Fuel Cell) technology is described and analyzed to investigate its commercialization prospects. An HT-PEMFC operates at elevated...

  5. EPR spectrometry of high temperature superconductors with temperature modulation

    International Nuclear Information System (INIS)

    Aliev, M.K.; Alimov, G.R.; Muminov, T.M.; Olimov, B.; Sokolov, B.Yh.; Usmanov, R.R.; Kholbaev, I.

    1996-01-01

    The system of thermoregulation through light beam within the temperature range of 77 -2 - 10 -1 K. The root-square temperature instability during 5 minutes does not exceed 0.06 K; the temperature gradient in the sample is approximately 0.01 K/mm by T ∼ 90 K. 10 refs., 2 figs

  6. Nontrivial center dominance in high temperature QCD

    Science.gov (United States)

    Ishikawa, K.-I.; Iwasaki, Y.; Nakayama, Yu; Yoshie, T.

    2016-07-01

    We investigate the properties of quarks and gluons above the chiral phase transition temperature Tc, using the renormalization group (RG) improved gauge action and the Wilson quark action with two degenerate quarks mainly on a 323 × 16 lattice. In the one-loop perturbation theory, the thermal ensemble is dominated by the gauge configurations with effectively Z(3) center twisted boundary conditions, making the thermal expectation value of the spatial Polyakov loop take a nontrivial Z(3) center. This is in agreement with our lattice simulation of high temperature quantum chromodynamics (QCD). We further observe that the temporal propagator of massless quarks at extremely high temperature β = 100.0(T ≃ 1058T c) remarkably agrees with the temporal propagator of free quarks with the Z(3) twisted boundary condition for t/Lt ≥ 0.2, but differs from that with the Z(3) trivial boundary condition. As we increase the mass of quarks mq, we find that the thermal ensemble continues to be dominated by the Z(3) twisted gauge field configurations as long as mq ≤ 3.0T and above that the Z(3) trivial configurations come in. The transition is similar to what we found in the departure from the conformal region in the zero-temperature many-flavor conformal QCD on a finite lattice by increasing the mass of quarks.

  7. High temperature cogeneration with thermionic burners

    Science.gov (United States)

    Fitzpatrick, G. O.; Britt, E. J.; Dick, R. S.

    The thermionic cogeneration combustor was conceived to meet industrial requirements for high-temperature direct heat, typically in the form of gas at temperatures from 800 to 1900 K, while at the same time supplying electricity. The thermionic combustor is entirely self-contained, with heat from the combustion region absorbed by the emitters of thermionic converters to be converted to electric power and the high-temperature reject heat from the converters used to preheat the air used for combustion. Depending on the temperature of the process gas produced, energy savings of around 10% with respect to that used to produce the same amount of electricity and heat without cogeneration are possible with present technology, and savings of up to 20% may be possible with advanced converters. Possible thermionic combustor designs currently under investigation include a configuration in which heat is collected by heat pipes lining the periphery of the combustion region, and a fire-tube converter in which combustion occurs within the cylindrical emitter of each converter. Preliminary component tests of these designs have been encouraging.

  8. Thermometry of a high temperature high speed micro heater.

    Science.gov (United States)

    Xu, M; Slovin, G; Paramesh, J; Schlesinger, T E; Bain, J A

    2016-02-01

    A high temperature high-speed tungsten micro heater was fabricated and tested for application in phase change switches to indirectly heat and transform phase change material. Time domain transmissometry was used to measure heater temperature transients for given electrical inputs. Finite element modeling results on heater temperature transients show a good consistency between experiments and simulations with 0.2% mismatch in the best case and 13.1% in the worst case. The heater described in this work can reliably reach 1664 K at a rate of 1.67 × 10(10) K/s and quench to room temperature with a thermal RC time constant (time for T to fall by a factor of e) of less than 40 ns.

  9. Decay properties of high-lying single-particles modes

    Science.gov (United States)

    Beaumel, D.; Fortier, S.; Galès, S.; Guillot, J.; Langevin-Joliot, H.; Laurent, H.; Maison, J. M.; Vernotte, J.; Bordewijck, J.; Brandenburg, S.; Krasznahorkay, A.; Crawley, G. M.; Massolo, C. P.; Renteria, M.; Khendriche, A.

    1996-02-01

    The neutron decay of high-lying single-particle states in 64Ni, 90Zr, 120Sn and 208Pb excited by means of the (α, 3He) reaction has been investigated at 120 MeV incident energy using the multidetector EDEN. The characteristics of this reaction are studied using inclusive spectra and angular correlation analysis. The structure located between 11 and 15 MeV in 91Zr, and between 8 and 12 MeV excitation energy in 209Pb display large departures from a pure statistical decay. The corresponding non-statistical branching ratios are compared with the results of two theoretical calculations.

  10. Surface single-molecule dynamics controlled by entropy at low temperatures

    Science.gov (United States)

    Gehrig, J. C.; Penedo, M.; Parschau, M.; Schwenk, J.; Marioni, M. A.; Hudson, E. W.; Hug, H. J.

    2017-02-01

    Configuration transitions of individual molecules and atoms on surfaces are traditionally described using an Arrhenius equation with energy barrier and pre-exponential factor (attempt rate) parameters. Characteristic parameters can vary even for identical systems, and pre-exponential factors sometimes differ by orders of magnitude. Using low-temperature scanning tunnelling microscopy (STM) to measure an individual dibutyl sulfide molecule on Au(111), we show that the differences arise when the relative position of tip apex and molecule changes by a fraction of the molecule size. Altering the tip position on that scale modifies the transition's barrier and attempt rate in a highly correlated fashion, which results in a single-molecular enthalpy-entropy compensation. Conversely, appropriately positioning the STM tip allows selecting the operating point on the compensation line and modifying the transition rates. The results highlight the need to consider entropy in transition rates of single molecules, even at low temperatures.

  11. Thermodynamic Temperatures of High-Temperature Fixed Points: Uncertainties Due to Temperature Drop and Emissivity

    Science.gov (United States)

    Castro, P.; Machin, G.; Bloembergen, P.; Lowe, D.; Whittam, A.

    2014-07-01

    This study forms part of the European Metrology Research Programme project implementing the New Kelvin to assign thermodynamic temperatures to a selected set of high-temperature fixed points (HTFPs), Cu, Co-C, Pt-C, and Re-C. A realistic thermal model of these HTFPs, developed in finite volume software ANSYS FLUENT, was constructed to quantify the uncertainty associated with the temperature drop across the back wall of the cell. In addition, the widely applied software package, STEEP3 was used to investigate the influence of cell emissivity. The temperature drop, , relates to the temperature difference due to the net loss of heat from the aperture of the cavity between the back wall of the cavity, viewed by the thermometer, defining the radiance temperature, and the solid-liquid interface of the alloy, defining the transition temperature of the HTFP. The actual value of can be used either as a correction (with associated uncertainty) to thermodynamic temperature evaluations of HTFPs, or as an uncertainty contribution to the overall estimated uncertainty. In addition, the effect of a range of furnace temperature profiles on the temperature drop was calculated and found to be negligible for Cu, Co-C, and Pt-C and small only for Re-C. The effective isothermal emissivity is calculated over the wavelength range from 450 nm to 850 nm for different assumed values of surface emissivity. Even when furnace temperature profiles are taken into account, the estimated emissivities change only slightly from the effective isothermal emissivity of the bare cell. These emissivity calculations are used to estimate the uncertainty in the temperature assignment due to the uncertainty in the emissivity of the blackbody.

  12. High Temperature Phenomena in Shock Waves

    CERN Document Server

    2012-01-01

    The high temperatures generated in gases by shock waves give rise to physical and chemical phenomena such as molecular vibrational excitation, dissociation, ionization, chemical reactions and inherently related radiation. In continuum regime, these processes start from the wave front, so that generally the gaseous media behind shock waves may be in a thermodynamic and chemical non-equilibrium state. This book presents the state of knowledge of these phenomena. Thus, the thermodynamic properties of high temperature gases, including the plasma state are described, as well as the kinetics of the various chemical phenomena cited above. Numerous results of measurement and computation of vibrational relaxation times, dissociation and reaction rate constants are given, and various ionization and radiative mechanisms and processes are presented. The coupling between these different phenomena is taken into account as well as their interaction with the flow-field. Particular points such as the case of rarefied flows an...

  13. Atomic processes in high temperature plasmas

    International Nuclear Information System (INIS)

    Hahn, Y.

    1990-03-01

    Much theoretical and experimental efforts have been expended in recent years to study those atomic processes which are specially relevant to understanding high temperature laboratory plasmas. For magnetically confined fusion plasmas, the temperature range of interest spans from the hundreds of eV at plasma edges to 10 keV at the center of the plasma, where most of the impurity ions are nearly fully ionized. These highly stripped ions interact strongly with electrons in the plasma, leading to further excitation and ionization of the ions, as well as electron capture. Radiations are emitted during these processes, which easily escape to plasma container walls, thus cooling the plasma. One of the dominant modes of radiation emission has been identified with dielectronic recombination. This paper reviews this work

  14. High temperature gas cooled nuclear reactor

    International Nuclear Information System (INIS)

    Hosegood, S.B.; Lockett, G.E.

    1975-01-01

    For high-temperature gas cooled reactors it is considered advantageous to design the core so that the moderator blocks can be removed and replaced by some means of standpipes normally situated in the top of the reactor vessel. An arrangement is here described to facilitate these operations. The blocks have end faces shaped as irregular hexagons with three long sides of equal length and three short sides also of equal length, one short side being located between each pair of adjacent long sides, and the long sides being inclined towards one another at 60 0 . The block defines a number of coolant channels located parallel to its sides. Application of the arrangement to a high temperature gas-cooled reactor with refuelling standpipes is described. The standpipes are located in the top of the reactor vessel above the tops of the columns and are disposed coaxially above the hexagonal channels, with diameters that allow the passage of the blocks. (U.K.)

  15. Trends in Surface Temperature at High Latitudes

    Science.gov (United States)

    Comiso, Josefino C.

    2012-01-01

    The earliest signal of a climate change is expected to be found in the polar regions where warming is expected to be amplified on account of ice-albedo feedbacks associated with the high reflectivity of snow and ice. Because of general inaccessibility, there is a general paucity of in situ data and hence the need to use satellite data to observe the large-scale variability and trends in surface temperature in the region. Among the most important sensors for monitoring surface temperature has been the Advanced Very High Resolution Radiometer (AVHRR) which was first launched in 1978 and has provided continuous thermal infrared data since 1981. The top of the atmosphere data are converted to surface temperature data through various schemes that accounts for the unique atmospheric and surface conditions in the polar regions. Among the highest source of error in the data is cloud masking which is made more difficult in the polar region because of similar Signatures of clouds and snow lice covered areas. The availability of many more channels in the Moderate Resolution Imaging Spectroradiometer (MODIS) launched on board Terra satellite in December 1999 and on board Aqua in May 2002 (e.g., 36 visible and infrared channels compared to 5 for AVHRR) made it possible to minimize the error. Further capabilities were introduced with the Advanced Microwave Scanning Radiometer (AMSR) which has the appropriate frequency channels for the retrieval of sea surface temperature (SST). The results of analysis of the data show an amplified warming in the Arctic region, compared with global warming. The spatial distribution of warming is, however, not uniform and during the last 3 decades, positive temperature anomalies have been most pronounced in North America, Greenland and the Arctic basin. Some regions of the Arctic such as Siberia and the Bering Sea surprisingly show moderate cooling but this may be because these regions were anomalously warm in the 1980s when the satellite record

  16. A method enabling simultaneous pressure and temperature measurement using a single piezoresistive MEMS pressure sensor

    International Nuclear Information System (INIS)

    Frantlović, Miloš; Stanković, Srđan; Jokić, Ivana; Lazić, Žarko; Smiljanić, Milče; Obradov, Marko; Vukelić, Branko; Jakšić, Zoran

    2016-01-01

    In this paper we present a high-performance, simple and low-cost method for simultaneous measurement of pressure and temperature using a single piezoresistive MEMS pressure sensor. The proposed measurement method utilizes the parasitic temperature sensitivity of the sensing element for both pressure measurement correction and temperature measurement. A parametric mathematical model of the sensor was established and its parameters were calculated using the obtained characterization data. Based on the model, a real-time sensor correction for both pressure and temperature measurements was implemented in a target measurement system. The proposed method was verified experimentally on a group of typical industrial-grade piezoresistive sensors. The obtained results indicate that the method enables the pressure measurement performance to exceed that of typical digital industrial pressure transmitters, achieving at the same time the temperature measurement performance comparable to industrial-grade platinum resistance temperature sensors. The presented work is directly applicable in industrial instrumentation, where it can add temperature measurement capability to the existing pressure measurement instruments, requiring little or no additional hardware, and without adverse effects on pressure measurement performance. (paper)

  17. Development of distributed temperature sensor based on single-mode fiber

    Science.gov (United States)

    Jiang, Mingshun; Wang, Jing; Feng, Dejun; Sui, Qingmei

    2008-12-01

    The distributed optical fiber temperature measurement system (DTS) is a kind of sensing system, which is applied to the real-time measurement of the temperature field in space. It is widely used in monitoring of production process: fire alarm of coal mine and fuel depots, heat detection and temperature monitor of underground cable, seepage and leakage of dam. Through analyzing temperature effect of optical fiber Raman backscattering theoretically, a distributed temperature sensor based on single-mode fiber was designed, which overcame the inadequacies of multimode fiber. The narrow pulse width laser, excellent InGaAS PIN, low noise precision difet operational amplifier and high speed data acquisition card in order to improve the stability of this system were selected. The demodulation method based on ratio of Anti-Stokes and Stokes Raman backscattering intensity was adopted. Both hardware composition and software implementation of the system were introduced in detail. It is proved that its distinguishing ability of temperature and space are 1 m and 2 m, respectively. The system response time is about 180 s, with a sensing range of 5 km and the temperature measurement range 0~100 °C.

  18. High-temperature radiation embrittlement of materials

    International Nuclear Information System (INIS)

    Zelenskij, V.F.; Kiryukhin, N.M.; Ozhigov, L.S.; Parkhomenko, A.A.

    1983-01-01

    On the basis of the analysis of literature data and the results obtained by the authors, main features and regularities of the high-temperature radiation embrittlement of materials (HTRE) are described. In important part of charged particle accelerator investigations for imitation and study of HTRE is pointed out. The existing HTRE models are analyzed and a new model taking into account the evolution of defect structure of matrix and grain boundaries under irradiation is suggested

  19. Intermetallic-Based High-Temperature Materials

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.

    1999-04-25

    The intermetallic-based alloys for high-temperature applications are introduced. General characteristics of intermetallics are followed by identification of nickel and iron aluminides as the most practical alloys for commercial applications. An overview of the alloy compositions, melting processes, and mechanical properties for nickel and iron aluminizes are presented. The current applications and commercial producers of nickel and iron aluminizes are given. A brief description of the future prospects of intermetallic-based alloys is also given.

  20. Passivation Of High-Temperature Superconductors

    Science.gov (United States)

    Vasquez, Richard P.

    1991-01-01

    Surfaces of high-temperature superconductors passivated with native iodides, sulfides, or sulfates formed by chemical treatments after superconductors grown. Passivating compounds nearly insoluble in and unreactive with water and protect underlying superconductors from effects of moisture. Layers of cuprous iodide and of barium sulfate grown. Other candidate passivating surface films: iodides and sulfides of bismuth, strontium, and thallium. Other proposed techniques for formation of passivating layers include deposition and gas-phase reaction.

  1. High Temperature Dimensional Reduction and Parity Violation

    CERN Document Server

    Kajantie, Keijo; Rummukainen, K; Shaposhnikov, Mikhail E

    1998-01-01

    The effective super-renormalizable 3-dimensional Lagrangian, describing the high temperature limit of chiral gauge theories, has more symmetry than the original 4d Lagrangian: parity violation is absent. Parity violation appears in the 3d theory only through higher-dimensional operators. We compute the coefficients of dominant P-odd operators in the Standard Electroweak theory and discuss their implications. We also clarify the parametric accuracy obtained with dimensional reduction.

  2. The battle of High Temperature Superconductivity

    OpenAIRE

    Lederer, Pascal

    2015-01-01

    The early development of conflicting theories about the microscopic mechanism of High Temperature Superconductivity is described. The biographical roots of this diversity are stressed, as well as its subjective/objective roots. This study of a specific case of knowledge about a specific fact of nature allows to discuss the subjective and objective roots of scientific pluralism. Relativism, the Duhem-Quine thesis on the underdetermination of theory by facts, are discussed from the stand point ...

  3. High Temperature Perforating System for Geothermal Applications

    Energy Technology Data Exchange (ETDEWEB)

    Smart, Moises E. [Schlumberger Technology Corporation, Sugar Land, TX (United States)

    2017-02-28

    The objective of this project is to develop a perforating system consisting of all the explosive components and hardware, capable of reliable performance in high temperatures geothermal wells (>200 ºC). In this light we will focused on engineering development of these components, characterization of the explosive raw powder and developing the internal infrastructure to increase the production of the explosive from laboratory scale to industrial scale.

  4. Very High Temperature Sound Absorption Coating, Phase II

    Data.gov (United States)

    National Aeronautics and Space Administration — Phase I demonstrated experimentally a very high temperature acoustically absorbing coating for ducted acoustics applications. High temperature survivability at 3500...

  5. High temperature and pressure alkaline electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank; Chatzichristodoulou, Christodoulos; Mogensen, Mogens Bjerg

    2013-01-01

    and pressures. Two measurement systems were built to perform measurements under high pressures and at elevated temperatures of up to 95 bar and 250 °C, respectively. The conductivity of aqueous KOH and aqueous KOH immobilized in a porous SrTiO3 structure were investigated at elevated temperatures and high...... concentrations of the electrolyte using the van der Pauw method in combination with electrochemical impedance spectroscopy (EIS). Conductivity values as high as 2.9 S cm-1 for 45 wt% KOH aqueous KOH and 0.84 S cm-1 for the immobilized KOH of the same concentration were measured at 200 °C. Porous SrTiO3 was used...... for immobilization of aqueous KOH solutions. Electrolysis cells with this electrolyte and metal foam based gas diffusion electrodes were successfully demonstrated at temperatures up to 250 °C at 40 bar. Different electro-catalysts were tested in order to reduce the oxygen and hydrogen overpotentials. Current...

  6. High temperature measurement of water vapor absorption

    Science.gov (United States)

    Keefer, Dennis; Lewis, J. W. L.; Eskridge, Richard

    1985-01-01

    An investigation was undertaken to measure the absorption coefficient, at a wavelength of 10.6 microns, for mixtures of water vapor and a diluent gas at high temperature and pressure. The experimental concept was to create the desired conditions of temperature and pressure in a laser absorption wave, similar to that which would be created in a laser propulsion system. A simplified numerical model was developed to predict the characteristics of the absorption wave and to estimate the laser intensity threshold for initiation. A non-intrusive method for temperature measurement utilizing optical laser-beam deflection (OLD) and optical spark breakdown produced by an excimer laser, was thoroughly investigated and found suitable for the non-equilibrium conditions expected in the wave. Experiments were performed to verify the temperature measurement technique, to screen possible materials for surface initiation of the laser absorption wave and to attempt to initiate an absorption wave using the 1.5 kW carbon dioxide laser. The OLD technique was proven for air and for argon, but spark breakdown could not be produced in helium. It was not possible to initiate a laser absorption wave in mixtures of water and helium or water and argon using the 1.5 kW laser, a result which was consistent with the model prediction.

  7. Directional droplet transport at high temperature mediated by structural topography

    Science.gov (United States)

    Li, Jing; Hou, Youmin; Chaudhury, Manoj; Yao, Shuhuai; Wang, Zuankai

    2015-11-01

    Controlling droplet dynamics on textured surfaces is of significant importance for a broad range of applications. Despite extensive advances, our ability to control droplet dynamics at high temperature remains limited, in part due to the emergence of complex wetting states complicated by the phase change process at the triple-phase interfaces. When the temperature of the surface is above a critical temperature, a continuous vapor layer separates the droplet from the hot surface, greatly reducing the heat transfer between the droplet and hot surface. In this work, we show that two concurrent wetting states (Leidenfrost and contact boiling) can be manifested in a single droplet by simply manipulating the structural topography. As a result, droplet vectors automatically towards the boiling region that is associated with a large heat transfer efficiency between the liquid and solid. Coupled with a dynamic Leidenfrost model, we show experimentally and analytically that the droplet directional motion depends on the interplay between surface structure and its imposed thermal state. Our basic understanding and ability to control the droplet dynamics at high temperature would find many potential applications in high temperature systems such as spray cooling and fuel injection.

  8. Neutron scattering at high temperature and levitation techniques

    Science.gov (United States)

    Cuello, G. J.; Cristiglio, V.; Hennet, L.; Puente-Orench, I.

    2014-11-01

    Studies of the liquid state present an obvious fundamental interest and are also important for technological applications since the molten state is an essential stage in various industrial processes (e.g. glass making, single crystal growing, iron and steel making). Most of the physical properties of a high-temperature liquid are related to its atomic structure. Thus it is important to develop devices to probe the local environment of the atoms in the sample. At very high temperature, it is difficult to use conventional furnaces, which present several problems. In particular, physical contact with the container can contaminate the sample and/or modify its structural properties. Such problems encouraged the development of containerless techniques, which are powerful tools to study high-temperature melts. By eliminating completely any contact between sample and container, it is possible to study the sample with a very high degree of control and to access very high temperatures. An additional advantage of levitation methods is that it is possible to supercool hot liquids down to several hundred of degrees below their equilibrium freezing point, since heterogeneous nucleation processes are suppressed.

  9. Neutron scattering at high temperature and levitation techniques

    International Nuclear Information System (INIS)

    Cuello, G J; Cristiglio, V; Puente-Orench, I; Hennet, L

    2014-01-01

    Studies of the liquid state present an obvious fundamental interest and are also important for technological applications since the molten state is an essential stage in various industrial processes (e.g. glass making, single crystal growing, iron and steel making). Most of the physical properties of a high-temperature liquid are related to its atomic structure. Thus it is important to develop devices to probe the local environment of the atoms in the sample. At very high temperature, it is difficult to use conventional furnaces, which present several problems. In particular, physical contact with the container can contaminate the sample and/or modify its structural properties. Such problems encouraged the development of containerless techniques, which are powerful tools to study high-temperature melts. By eliminating completely any contact between sample and container, it is possible to study the sample with a very high degree of control and to access very high temperatures. An additional advantage of levitation methods is that it is possible to supercool hot liquids down to several hundred of degrees below their equilibrium freezing point, since heterogeneous nucleation processes are suppressed

  10. High Temperature VARTM of Phenylethynyl Terminated Imides

    Science.gov (United States)

    Cano, Roberto J.; Britton, Sean M.; Jensen, Brian J.; Connell, John W.; Herring, Helen M.; Linberry, Quentin J.; Ghose, Sayata; Watson, Kent A.

    2009-01-01

    Fabrication of composite structures using vacuum assisted resin transfer molding (VARTM) is generally more affordable than conventional autoclave techniques. Recent efforts have focused on adapting VARTM for the fabrication of high temperature composites. Due to their low melt viscosity and long melt stability, certain phenylethynyl terminated imides (PETI) can be processed into composites using high temperature VARTM (HT-VARTM). However, one of the disadvantages of the current HT-VARTM resin systems has been the high porosity of the resultant composites. For aerospace applications, the desired void fraction of less than 2% has not yet been achieved. In the current study, two PETI resins, LaRC PETI-330 and LaRC PETI-8 have been used to make test specimens using HT-VARTM. The resins were infused into ten layers of IM7-6K carbon fiber 5-harness satin fabric at 260 C or 280 C and cured at 371 C. Initial runs yielded composites with high void content, typically greater than 7% by weight. A thermogravimetric-mass spectroscopic study was conducted to determine the source of volatiles leading to high porosity. It was determined that under the thermal cycle used for laminate fabrication, the phenylethynyl endcap was undergoing degradation leading to volatile evolution. By modifying the thermal cycle used in laminate fabrication, the void content was reduced significantly (typically approximately 3%). Densities of the composites were determined using a density gradient column and the glass transition temperatures of the cured composites were measured by dynamic mechanical analysis. Photomicrographs of the panels were taken and void contents were determined by acid digestion. The results of this work are presented herein.

  11. High-temperature brushless DC motor controller

    Science.gov (United States)

    Cieslewski, Crzegorz; Lindblom, Scott C.; Maldonado, Frank J.; Eckert, Michael Nathan

    2017-05-16

    A motor control system for deployment in high temperature environments includes a controller; a first half-bridge circuit that includes a first high-side switching element and a first low-side switching element; a second half-bridge circuit that includes a second high-side switching element and a second low-side switching element; and a third half-bridge circuit that includes a third high-side switching element and a third; low-side switching element. The motor controller is arranged to apply a pulse width modulation (PWM) scheme to switch the first half-bridge circuit, second half-bridge circuit, and third half-bridge circuit to power a motor.

  12. Mitigation of Temperature Induced Single Event Crosstalk Noise by Applying Adaptive Forward Body Bias

    Science.gov (United States)

    Bhowmik, Pankaj

    Soft Errors due to Single Event (SE) Transients is one of the important reliability issues, which is becoming very prominent in advanced technology and in space applications. Increasing coupling effects among interconnects, on the other hand, can cause SE Transients to contaminate electronically unrelated circuit paths, which in turn can increase circuit sensitivity to radiation. Coupling capacitance increases due to reducing distances between interconnect lines making crosstalk noise more important. On the other hand, chips now experience higher temperatures due to environmental factors and high performance of chips. High-performance VLSI circuits consume more power and hence experience higher temperature due to high utilization factor. The increased temperature affects both interconnect resistance and driving strength of interconnect buffers. This work shows that thermal effects increase the amount of crosstalk noise observed on the victim line at nominal supply voltages. With thermally induced crosstalk contribution, total crosstalk noise may exceed the noise margin of the subsequent gate causing a wrong value to be propagated. The crosstalk prevention measures taken such as victim driver sizing may not be sufficient if thermal effects are not properly considered. This work aims to provide a mitigation method for thermally induced crosstalk noise using adaptive forward body bias. At high temperature, drain current reduces, and adaptive body biasing makes the CMOS recover the lost the drain current. A temperature sensor is proposed here to generate a necessary voltage at the CMOS body. A good temperature sensitivity is achieved with the tiny sensors that keep constant driving strength. Interconnect is modeled in using 10-pi modeling and 45nm technology was use for this simulation. Our proposed method mitigates 90% of temperature induced crosstalk contribution.

  13. Microstructural Evolution and Mechanical Behavior of High Temperature Solders: Effects of High Temperature Aging

    Science.gov (United States)

    Hasnine, M.; Tolla, B.; Vahora, N.

    2018-04-01

    This paper explores the effects of aging on the mechanical behavior, microstructure evolution and IMC formation on different surface finishes of two high temperature solders, Sn-5 wt.% Ag and Sn-5 wt.% Sb. High temperature aging showed significant degradation of Sn-5 wt.% Ag solder hardness (34%) while aging has little effect on Sn-5 wt.% Sb solder. Sn-5 wt.% Ag experienced rapid grain growth as well as the coarsening of particles during aging. Sn-5 wt.% Sb showed a stable microstructure due to solid solution strengthening and the stable nature of SnSb precipitates. The increase of intermetallic compound (IMC) thickness during aging follows a parabolic relationship with time. Regression analysis (time exponent, n) indicated that IMC growth kinetics is controlled by a diffusion mechanism. The results have important implications in the selection of high temperature solders used in high temperature applications.

  14. Development of Very High Temperature Reactor Technology

    International Nuclear Information System (INIS)

    Lee, Won Jae; Noh, J. M.; Kim, Y. H.

    2009-04-01

    For an efficient production of nuclear hydrogen, the VHTR (Very High Temperature Gas-cooled Reactor) of 950 .deg. C outlet temperature and the interfacing system for the hydrogen production are required. We have developed various evaluation technologies for the performance and safety of VHTR through the accomplishment of this project. First, to evaluate the performance of VHTR, a series of analyses has been performed such as core characteristics at 950 .deg. C, applicability of cooled-vessel, intermediate loop system and high temperature structural integrity. Through the analyses of major accidents such as HPCC and LPCC and the analysis of the risk/performance-informed method, VHTR safety evaluation has been also performed. In addition, various design analysis codes have been developed for a nuclear design, system loop design, system performance analysis, air-ingress accident analysis, fission product/tritium transport analysis, graphite structure seismic analysis and hydrogen explosion analysis, and they are being verified and validated through a lot of international collaborations

  15. Isotopic effect in high temperature superconductors

    International Nuclear Information System (INIS)

    Ohno, Takashi

    2000-01-01

    It is well-known that it essentially contributed to construct the BCB theory that a mechanism on formation of the Cooper pairs was dependent upon a lattice oscillation to change a critical temperature, T(sub c) of a superconductor with isotopic displacement. In this paper, here was, at first, described on an isotopic index actually measured to high temperature superconductors, and was introduced on a study on selective displacement of oxygen position. And then, a detailed measurement of 63-Cu(2) nuclear quadrupole resonance (NQR) at a plane position of YBa2Cu4O8 (Y1248) displaced with 18-O and 16-O, discussion of the isotopic effect on a base of 63-Cu(2) nuclear spin-lattice relaxation ratio, and consideration on the isotopic index according to the isotopic effect were described. As a result of the considerations, it could be concluded that the isotopic effect in a high temperature superconductor proved that antiferromagnetic spin fluctuation was an origin of Cooper pairs cohesive strength. (G.K.)

  16. Oxidation behavior of rhenium at high temperatures

    International Nuclear Information System (INIS)

    Chou, T.C.; Joshi, A.; Packer, C.M.

    1993-01-01

    Oxidation of polycrystalline Re has been studied at temperatures from 1,500 to 1,900 C. During oxidation volatile Re-oxides were emitted in the form of smoke and resulted in dramatic surface recessions of the samples. XRD analysis indicated that ReO 3 was the primary oxide present in the condensed vapor deposits. Preferential oxidation of Re, manifested by the formation of crystallographic facets, was noted on the oxidized surfaces. Etchpits and islands bounded by high-symmetry planes showing a 6-fold symmetry were formed thereon, suggesting that the kinetics of oxidation are slower on close-packed planes. It is demonstrated that surface recession rate, dR/dt, which is equivalent to weight change per unit area and time (dW/A·dt), can be used to characterize oxidation behavior. The overall surface recessions of both the PM-Re and CVD-Re generally increased with oxidation duration and temperature. The CVD-Re exhibits lower recession rates than the PM-Re in the temperature range examined, which is attributable to the stronger basal-plane texture and larger grain size of CVD-Re. Oxidation of PM-Re was observed to be anisotropic. At 1500 degree C, oxidation rates on the direction I (rolling plane) were higher. At higher temperatures (1,700 and 1,900 C), on the other hand, an opposite result was obtained. The differential oxidation rate of the PM-Re is suggested to originate from the synergistic effects of temperature-dependent oxidation behavior and basal-plane texture that have evolved during sample processing. This hypothesis is consistent with the fact that similar activation energies were obtained for the oxidation of CVD-Re and PM-Re (I)

  17. Temperature profiles in high gradient furnaces

    Science.gov (United States)

    Fripp, A. L.; Debnam, W. J.; Woodell, G. A.; Berry, R.; Crouch, R. K.; Sorokach, S. K.

    1989-01-01

    Accurate temperature measurement of the furnace environment is very important in both the science and technology of crystal growth as well as many other materials processing operations. A high degree of both accuracy and precision is acutely needed in the directional solidification of compound semiconductors in which the temperature profiles control the freezing isotherm which, in turn, affects the composition of the growth with a concomitant feedback perturbation on the temperature profile. Directional solidification requires a furnace configuration that will transport heat through the sample being grown. A common growth procedure is the Bridgman Stockbarger technique which basically consists of a hot zone and a cold zone separated by an insulator. In a normal growth procedure the material, contained in an ampoule, is melted in the hot zone and is then moved relative to the furnace toward the cold zone and solidification occurs in the insulated region. Since the primary path of heat between the hot and cold zones is through the sample, both axial and radial temperature gradients exist in the region of the growth interface. There is a need to know the temperature profile of the growth furnace with the crystal that is to be grown as the thermal load. However it is usually not feasible to insert thermocouples inside an ampoule and thermocouples attached to the outside wall of the ampoule have both a thermal and a mechanical contact problem as well as a view angle problem. The objective is to present a technique of calibrating a furnace with a thermal load that closely matches the sample to be grown and to describe procedures that circumvent both the thermal and mechanical contact problems.

  18. Creep resistant high temperature martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, Jeffrey A.; Jablonski, Paul D.; Cowen, Christopher J.

    2015-11-13

    The disclosure provides a creep resistant alloy having an overall composition comprised of iron, chromium, molybdenum, carbon, manganese, silicon, nickel, vanadium, niobium, nitrogen, tungsten, cobalt, tantalum, boron, and potentially additional elements. In an embodiment, the creep resistant alloy has a molybdenum equivalent Mo(eq) from 1.475 to 1.700 wt. % and a quantity (C+N) from 0.145 to 0.205. The overall composition ameliorates sources of microstructural instability such as coarsening of M.sub.23C.sub.6 carbides and MX precipitates, and mitigates or eliminates Laves and Z-phase formation. A creep resistant martensitic steel may be fabricated by preparing a melt comprised of the overall composition followed by at least austenizing and tempering. The creep resistant alloy exhibits improved high-temperature creep strength in the temperature environment of around 650.degree. C.

  19. Creep resistant high temperature martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

    Hawk, Jeffrey A.; Jablonski, Paul D.; Cowen, Christopher J.

    2017-01-31

    The disclosure provides a creep resistant alloy having an overall composition comprised of iron, chromium, molybdenum, carbon, manganese, silicon, nickel, vanadium, niobium, nitrogen, tungsten, cobalt, tantalum, boron, copper, and potentially additional elements. In an embodiment, the creep resistant alloy has a molybdenum equivalent Mo(eq) from 1.475 to 1.700 wt. % and a quantity (C+N) from 0.145 to 0.205. The overall composition ameliorates sources of microstructural instability such as coarsening of M.sub.23C.sub.6carbides and MX precipitates, and mitigates or eliminates Laves and Z-phase formation. A creep resistant martensitic steel may be fabricated by preparing a melt comprised of the overall composition followed by at least austenizing and tempering. The creep resistant alloy exhibits improved high-temperature creep strength in the temperature environment of around 650.degree. C.

  20. Permanent magnets composed of high temperature superconductors

    Science.gov (United States)

    Weinstein, Roy; Chen, In-Gann; Liu, Jay; Lau, Kwong

    1991-01-01

    A study of persistent, trapped magnetic field has been pursued with high-temperature superconducting (HTS) materials. The main effort is to study the feasibility of utilization of HTS to fabricate magnets for various devices. The trapped field, when not in saturation, is proportional to the applied field. Thus, it should be possible to replicate complicated field configurations with melt-textured YBa2Cu3O7 (MT-Y123) material, bypassing the need for HTS wires. Presently, materials have been developed from which magnets of 1.5 T, at 77 K, can be fabricated. Much higher field is available at lower operating temperature. Stability of a few percent per year is readily attainable. Results of studies on prototype motors and minimagnets are reported.

  1. Operator manual: high temperature heat pump

    Energy Technology Data Exchange (ETDEWEB)

    Dyer, D.F.; Maples, G.; Burch, T.E.; Chancellor, P.D.

    1980-03-04

    Experimental data is being obtained from operating a high temperature heat pump system. The use of methanol as a working fluid will necessitate careful monitoring of refrigerant temperatures and pressures with chemical analysis performed on the working fluid during scheduled down time. Materials sent to vendors by Auburn University and quotes received by Auburn concerning equipment (compressor, evaporator, condensor, air heater, dryer, two accumulator tanks, and three expansion valves) are discussed. The simulated dryer and two accumulator tanks were designed by Auburn. The detailed design and pricing estimates are included. Additional information is presented on layout and construction; start-up; testing; shut down; scheduled maintenance and inspection; safety precautions; control system; and trouble shooting.

  2. Temperature Prediction for High Pressure High Temperature Condensate Gas Flow Through Chokes

    Directory of Open Access Journals (Sweden)

    Changjun Li

    2012-03-01

    Full Text Available This study developed a theoretical model for predicting the downstream temperatures of high pressure high temperature condensate gas flowing through chokes. The model is composed of three parts: the iso-enthalpy choke model derived from continuity equation and energy conservation equation; the liquid-vapor equilibrium model based on the SRK equation of state (EoS; and the enthalpy model based on the Lee-Kesler EoS. Pseudocritical properties of mixtures, which are obtained by mixing rules, are very important in the enthalpy model, so the Lee-Kesler, Plocker-Knapp, Wong-Sandler and Prausnitz-Gunn mixing rules were all researched, and the combination mixing rules with satisfactory accuracy for high pressure high temperature condensate gases were proposed. The temperature prediction model is valid for both the critical and subcritical flows through different kinds of choke valves. The applications show the model is reliable for predicting the downstream temperatures of condensate gases with upstream pressures up to 85.54 MPa and temperatures up to 93.23 °C. The average absolute errors between the measured and calculated temperatures are expected for less than 2 °C by using the model.

  3. High-Temperature-High-Volume Lifting for Enhanced Geothermal Systems

    Energy Technology Data Exchange (ETDEWEB)

    Turnquist, Norman [GE Global Research, Munchen (Germany); Qi, Xuele [GE Global Research, Munchen (Germany); Raminosoa, Tsarafidy [GE Global Research, Munchen (Germany); Salas, Ken [GE Global Research, Munchen (Germany); Samudrala, Omprakash [GE Global Research, Munchen (Germany); Shah, Manoj [GE Global Research, Munchen (Germany); Van Dam, Jeremy [GE Global Research, Munchen (Germany); Yin, Weijun [GE Global Research, Munchen (Germany); Zia, Jalal [GE Global Research, Munchen (Germany)

    2013-12-20

    This report summarizes the progress made during the April 01, 2010 – December 30, 2013 period under Cooperative Agreement DE-EE0002752 for the U.S. Department of Energy entitled “High-Temperature-High-Volume Lifting for Enhanced Geothermal Systems.” The overall objective of this program is to advance the technology for well fluids lifting systems to meet the foreseeable pressure, temperature, and longevity needs of the Enhanced Geothermal Systems (EGS) industry for the coming ten years. In this program, lifting system requirements for EGS wells were established via consultation with industry experts and site visits. A number of artificial lift technologies were evaluated with regard to their applicability to EGS applications; it was determined that a system based on electric submersible pump (ESP) technology was best suited to EGS. Technical barriers were identified and a component-level technology development program was undertaken to address each barrier, with the most challenging being the development of a power-dense, small diameter motor that can operate reliably in a 300°C environment for up to three years. Some of the targeted individual component technologies include permanent magnet motor construction, high-temperature insulation, dielectrics, bearings, seals, thrust washers, and pump impellers/diffusers. Advances were also made in thermal management of electric motors. In addition to the overall system design for a full-scale EGS application, a subscale prototype was designed and fabricated. Like the full-scale design, the subscale prototype features a novel “flow-through-the-bore” permanent magnet electric motor that combines the use of high temperature materials with an internal cooling scheme that limits peak internal temperatures to <330°C. While the full-scale high-volume multi-stage pump is designed to lift up to 80 kg/s of process water, the subscale prototype is based on a production design that can pump 20 kg/s and has been modified

  4. Penetration depth study of high temperature and other novel superconductors

    CERN Document Server

    Manzano, F

    2002-01-01

    penetration depth of lambda sub a (0) = (1100 +- 200)A was yielded. YBa sub 2 Cu sub 4 O sub 8 single crystals were measured to observe any contribution from Andreev boundstates. No evidence for this was found. The penetration depth was seen to decrease at low temperature rather than follow the linear temperature dependence associated with d sub x sub + 2 sub - sub y sub + 2 superconductivity. This low temperature decrease was seen to be increasingly suppressed for magnetic fields above approx 5 mT. The effect was attributed to the suppression of superconductivity along the CuO chains. An attempt was made to separate each of the penetration depth (DELTA lambda sub a (T), DELTA lambda sub b (T) and DELTA lambda sub c (T)) components using geometrical arguments. A high stability LC-oscillator technique was used to perform penetration depth measurements on optimally doped YBa sub 2 Cu sub 3 O sub 7 single crystals, naturally underdoped YBa sub 2 Cu sub 4 O sub 8 single crystals and the novel, newly discovered su...

  5. Use of Single-Tow Ceramic Matrix Minicomposites to Determine Fundamental Room and Elevated Temperature Properties

    Science.gov (United States)

    Almansour, Amjad S.

    The room and high temperature mechanical properties of continuous ceramic fiber reinforced matrix composites makes them attractive for implementation in aerospace and nuclear applications. However, the effect of fiber content has not been addressed in previous work. Therefore, single tow composites with fiber content ranging from 3 to 47 % was studied. Single fiber tow minicomposite is the basic architectural feature of woven and laminate ceramic matrix composites (CMCs). An in depth understanding of the initiation and evolution of damage in various ceramic fiber reinforced minicomposites with different fiber volume fractions and interphases was investigated employing several non-destructive evaluation techniques. A new technique is used to determine matrix crack content based on a damage parameter derived from speed of sound measurements which is compared with the established method using cumulative energy of Acoustic Emission (AE) events. Also, a modified theoretical model was implemented to obtain matrix stress at the onset of matrix cracking. Room temperature tensile, high temperature creep rupture and high temperature oxidation degradation loading conditions were all considered and composites' constituents were characterized. Moreover, fibers/matrix load sharing was modeled in creep and fiber volume fraction effect on load transfer was investigated using derived theoretical models. Fibers and matrix creep parameters, load transfer model results and numerical model methodology were used to construct minicomposites' creep strain model to predict creep damage of the different fiber type and content minicomposites. Furthermore, different fiber volume fractions ceramic matrix minicomposites' electrical resistivity temperature dependence isn't well understood. Therefore, the influence of fiber content, heat treatment cycles and creep on electrical resistivity measurements of SiC/SiC minicomposites were also studied here. Next, minicomposites' testing and

  6. High temperature electrolysis for hydrogen production using nuclear energy

    International Nuclear Information System (INIS)

    Herring, J. Stephen; O'brien, James E.; Stoots, Carl M.; Hawkes, Grant L.; Hartvigsen, Joseph J.

    2005-01-01

    High-temperature nuclear reactors have the potential for substantially increasing the efficiency of hydrogen production from water splitting, which can be accomplished via high-temperature electrolysis (HTE) or thermochemical processes. In order to achieve competitive efficiencies, both processes require high-temperature operation (∼850degC). High-temperature electrolytic water splitting supported by nuclear process heat and electricity has the potential to produce hydrogen with overall system efficiencies of 45 to 55%. At the Idaho National Laboratory, we are developing solid-oxide cells to operate in the steam electrolysis mode. The research program includes both experimental and modeling activities. Experimental results were obtained from ten-cell and 22-cell planar electrolysis stacks, fabricated by Ceramatec, Inc. The electrolysis cells are electrolyte-supported, with scandia-stabilized zirconia electrolytes (∼200 μm thick, 64 cm 2 active area), nickel-cermet steam/hydrogen electrodes, and manganite air-side electrodes. The metallic interconnect plates are fabricated from ferritic stainless steel. The experiments were performed over a range of steam inlet mole fractions, gas glow rates, and current densities. Hydrogen production rates greater than 100 normal liters per hour for 196 hours have been demonstrated. In order to evaluate the performance of large-scale HTE operations, we have developed single-cell models, based on FLUENT, and a process model, using the systems-analysis code HYSYS. (author)

  7. Decay properties of high-lying single-particles modes

    Energy Technology Data Exchange (ETDEWEB)

    Beaumel, D. [Institut de Physique Nucleaire, 91 - Orsay (France); Fortier, S. [Institut de Physique Nucleaire, 91 - Orsay (France); Gales, S. [Institut de Physique Nucleaire, 91 - Orsay (France); Guillot, J. [Institut de Physique Nucleaire, 91 - Orsay (France); Langevin-Joliot, H. [Institut de Physique Nucleaire, 91 - Orsay (France); Laurent, H. [Institut de Physique Nucleaire, 91 -Orsay (France); Maison, J.M. [Institut de Physique Nucleaire, 91 - Orsay (France); Vernotte, J. [Institut de Physique Nucleaire, 91 - Orsay (France); Bordewijck, J. [Kernfysisch Versneller Instituut, 9747 Groningen (Netherlands); Brandenburg, S. [Kernfysisch Versneller Instituut, 9747 Groningen (Netherlands); Krasznahorkay, A. [Kernfysisch Versneller Instituut, 9747 Groningen (Netherlands); Crawley, G.M. [NSCL, Michigan State University, East Lansing, MI 48824 (United States); Massolo, C.P. [Universitad Nacional de La Plata, 1900 La Plata (Argentina); Renteria, M. [Universitad Nacional de La Plata, 1900 La Plata (Argentina); Khendriche, A. [University of Tizi-Ouzou, Tizi-Ouzou (Algeria)

    1996-03-18

    The neutron decay of high-lying single-particle states in {sup 64}Ni, {sup 90}Zr, {sup 120}Sn and {sup 208}Pb excited by means of the ({alpha},{sup 3}He) reaction has been investigated at 120 MeV incident energy using the multidetector EDEN. The characteristics of this reaction are studied using inclusive spectra and angular correlation analysis. The structure located between 11 and 15 MeV in {sup 91}Zr, and between 8 and 12 MeV excitation energy in {sup 209}Pb display large departures from a pure statistical decay. The corresponding non-statistical branching ratios are compared with the results of two theoretical calculations. (orig.).

  8. High-temperature superconductors make major progress

    CERN Multimedia

    CERN Bulletin

    2014-01-01

    This month's Nature Materials featured an important breakthrough for high-temperature superconductors. A new method has been found for processing Bi-2212 high-temperature superconducting round wire in order to drastically increase its critical current density. The result confirms that this conductor is a serious candidate for future very-high-field magnets.   This image shows the cross-section of two Bi-2212 wires. The bottom wire has less leakage and void porosity due to a heat treatment done at an overpressure of 100 bar - about 100 times the pressure used to produce the top wire (image from [Nature Materials, Vol. 13 (2014), 10.1038/nmat3887]). The workhorse for building superconducting accelerator magnets has been, so far, the Niobium-Titanium (Nb-Ti) alloy superconductor. But with Nb-Ti having reached its full potential, other conductors must be used to operate in higher magnetic fields beyond those reached with the LHC magnets. Today, the intermetallic Niobium-Tin (Nb3Sn) is th...

  9. Simulation of silicon nanoparticles stabilized by hydrogen at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Galashev, Alexander Y., E-mail: galashev@ecko.uran.r [Russian Academy of Sciences, Ural Division, Institute of Industrial Ecology (Russian Federation)

    2010-10-15

    The stability of different silicon nanoparticles are investigated at a high temperature. The temperature dependence of the physicochemical properties of 60- and 73-atom silicon nanoparticles are investigated using the molecular dynamics method. The 73-atom particles have a crystal structure, a random atomic packing, and a packing formed by inserting a 13-atom icosahedron into a 60-atom fullerene. They are surrounded by a 'coat' from 60 atoms of hydrogen. The nanoassembled particle at the presence of a hydrogen 'coat' has the most stable number (close to four) of Si-Si bonds per atom. The structure and kinetic properties of a hollow single-layer fullerene-structured Si{sub 60} cluster are considered in the temperature range 10 K {<=} T {<=} 1760 K. Five series of calculations are conducted, with a simulation of several media inside and outside the Si{sub 60} cluster, specifically, the vacuum and interior spaces filled with 30 and 60 hydrogen atoms with and without the exterior hydrogen environment of 60 atoms. Fullerene surrounded by a hydrogen 'coat' and containing 60 hydrogen atoms in the interior space has a higher stability. Such cluster has smaller self-diffusion coefficients at high temperatures. The fullerene stabilized with hydrogen is stable to the formation of linear atomic chains up to the temperatures 270-280 K.

  10. High Temperature Corrosion in Biomass Incineration Plants

    DEFF Research Database (Denmark)

    Montgomery, Melanie; Maahn, Ernst emanuel; Gotthjælp, K.

    1997-01-01

    The aim of the project is to study the role of ash deposits in high temperature corrosion of superheater materials in biomass and refuse fire combined heat and power plants. The project has included the two main activities: a) A chemical characterisation of ash deposits collected from a major...... number of biomass and refuse fired combined heat and power plant boilers, b) Laboratory exposures and metallurgical examinations of material specimens with ash deposits in well-defined gas environments with HCl and SO2 in a furnace....

  11. Multichannel euv spectroscopy of high temperature plasmas

    International Nuclear Information System (INIS)

    Fonck, R.J.

    1983-11-01

    Spectroscopy of magnetically confined high temperature plasmas in the visible through x-ray spectral ranges deals primarily with the study of impurity line radiation or continuum radiation. Detailed knowledge of absolute intensities, temporal behavior, and spatial distributions of the emitted radiation is desired. As tokamak facilities become more complex, larger, and less accessible, there has been an increased emphasis on developing new instrumentation to provide such information in a minimum number of discharges. The availability of spatially-imaging detectors for use in the vacuum ultraviolet region (especially the intensified photodiode array) has generated the development of a variety of multichannel spectrometers for applications on tokamak facilities

  12. Experimental needs of high temperature concrete

    International Nuclear Information System (INIS)

    Chern, J.C.; Marchertas, A.H.

    1985-01-01

    The needs of experimental data on concrete structures under high temperature, ranging up to about 370 0 C for operating reactor conditions and to about 900 0 C and beyond for hypothetical accident conditions, are described. This information is required to supplement analytical methods which are being implemented into the finite element code TEMP-STRESS to treat reinforced concrete structures. Recommended research ranges from material properties of reinforced/prestressed concrete, direct testing of analytical models used in the computer codes, to investigations of certain aspects of concrete behavior, the phenomenology of which is not well understood. 10 refs

  13. High temperature decomposition of hydrogen peroxide

    Science.gov (United States)

    Parrish, Clyde F. (Inventor)

    2011-01-01

    Nitric oxide (NO) is oxidized into nitrogen dioxide (NO.sub.2) by the high temperature decomposition of a hydrogen peroxide solution to produce the oxidative free radicals, hydroxyl and hydroperoxyl. The hydrogen peroxide solution is impinged upon a heated surface in a stream of nitric oxide where it decomposes to produce the oxidative free radicals. Because the decomposition of the hydrogen peroxide solution occurs within the stream of the nitric oxide, rapid gas-phase oxidation of nitric oxide into nitrogen dioxide occurs.

  14. Encapsulation of high temperature molten salts

    Science.gov (United States)

    Oxley, James D.; Mathur, Anoop Kumar

    2017-05-16

    The present disclosure relates to a method of encapsulating microcapsules containing relatively high temperature phase change materials and the microcapsules so produced. The microcapsules are coated with an inorganic binder, film former and an inorganic filler. The microcapsules may include a sacrificial layer that is disposed between the particle and the coating. The microcapsules may also include an inner coating layer, sacrificial layer and outer coating layer. The microcapsules are particularly useful for thermal energy storage in connection with, e.g., heat collected from concentrating solar collectors.

  15. 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.

  16. Thermal conductivity in high critical temperature superconductors

    International Nuclear Information System (INIS)

    Castello, D.J.

    1990-01-01

    A measuring procedure to obtain the electrical resistivity, thermal conductivity and thermoelectric power of samples of low conductivity has been developed. The setup was designed to allow the removal of the sample in clean fashion, so that further heat treatments could be performed, and therefore no adhesives were used in the mounting of the thermocouples or heat sinks, etc. The heat equation has been analyzed with time-dependent boundary conditions, with the purpose of developing a dynamic measuring method which avoids the long delays involved in reaching thermal equilibrium above 30K. Based on this analysis, the developed measuring method allows a precise and reliable measurements, in a continuous fashion, for temperatures above 25K. The same setup is used in a stationary mode at low temperatures, so the sample needs to be mounted only once. κ(T) has been measured in two ceramic samples of La 2 CuO 4 : the first semiconducting, the other superconducting (SC) as a consequence of an oxygen annealing. Both exhibit a strong thermal resistivity due to defects, though lower in the SC, where two maxima are observed and are attributed to an AF ordering: T N ' ≅ 40K and T N '' ≅ 240K. The low temperature dependence is T 1 .6 and T 2 .3 respectively. It was interpreted that the former sample presents a greater dispersion due to localized excitations, characteristic of amorphouus materials, 'tunneling two-level systems' (TS). A third syntherized sample of CuO exhibits a typical behaviour of an insulator, with T 2 .6 at low temperatures, a maximum at 40K and a decrease in T -1 at high temperatures. κ(T) in a SC sample of La 1 .85Sr 1 .15CuO 4 with T c =35.5K has also been measured, observing a small increase below T c because of the diminishing of the phonon dispersion due to the condensating electrons. κ(T) is lower than in the previous samples and thus a greater number of defects was inferred. At low temperatures, its dependence is T 1 .4 in agreement with the

  17. Thermal stability of high temperature structural alloys

    Energy Technology Data Exchange (ETDEWEB)

    Jordan, C.E.; Rasefske, R.K.; Castagna, A. [Lockheed Martin Corp., Schenectady, NY (United States)

    1999-03-01

    High temperature structural alloys were evaluated for suitability for long term operation at elevated temperatures. The effect of elevated temperature exposure on the microstructure and mechanical properties of a number of alloys was characterized. Fe-based alloys (330 stainless steel, 800H, and mechanically alloyed MA 956), and Ni-based alloys (Hastelloy X, Haynes 230, Alloy 718, and mechanically alloyed MA 758) were evaluated for room temperature tensile and impact toughness properties after exposure at 750 C for 10,000 hours. Of the Fe-based alloys evaluated, 330 stainless steel and 800H showed secondary carbide (M{sub 23}C{sub 6}) precipitation and a corresponding reduction in ductility and toughness as compared to the as-received condition. Within the group of Ni-based alloys tested, Alloy 718 showed the most dramatic structure change as it formed delta phase during 10,000 hours of exposure at 750 C with significant reductions in strength, ductility, and toughness. Haynes 230 and Hastelloy X showed significant M{sub 23}C{sub 6} carbide precipitation and a resulting reduction in ductility and toughness. Haynes 230 was also evaluated after 10,000 hours of exposure at 850, 950, and 1050 C. For the 750--950 C exposures the M{sub 23}C{sub 6} carbides in Haynes 230 coarsened. This resulted in large reductions in impact strength and ductility for the 750, 850 and 950 C specimens. The 1050 C exposure specimens showed the resolution of M{sub 23}C{sub 6} secondary carbides, and mechanical properties similar to the as-received solution annealed condition.

  18. High power densities from high-temperature material interactions

    Energy Technology Data Exchange (ETDEWEB)

    Morris, J.F.

    1981-01-01

    Thermionic energy conversion (TEC) and metallic-fluid heat pipes (MFHPs) offer important and unique advantages in terrestrial and space energy processing. And they are well suited to serve together synergistically. TEC and MFHPs operate through working-fluid vaporization, condensation cycles that accept great thermal power densities at high temperatures. TEC and MFHPs have apparently simple, isolated performance mechanisms that are somewhat similar. And they also have obviously difficult, complected material problems that again are somewhat similar. Intensive investigation reveals that aspects of their operating cycles and material problems tend to merge: high-temperature material effects determine the level and lifetime of performance. Simplified equations verify the preceding statement for TEC and MFHPs. Material properties and interactions exert primary influences on operational effectiveness. And thermophysicochemical stabilities dictate operating temperatures which regulate the thermoemissive currents of TEC and the vaporization flow rates of MFHPs. Major high-temperature material problems of TEC and MFHPs have been solved. These solutions lead to productive, cost-effective applications of current TEC and MFHPs - and point to significant improvements with anticipated technological gains.

  19. NMR and MRI obtained with high transition temperature dc SQUIDs

    Directory of Open Access Journals (Sweden)

    Souza R.E. de

    1999-01-01

    Full Text Available We have measured nuclear magnetic resonance (NMR signals from several samples at room temperature in magnetic fields ranging from about 0.05 mT to 2 mT using a spectrometer based on a high-Tc dc SQUID (high transition temperature dc Superconducting QUantum Interference Device. We are able to observe proton signals from 1 mL of mineral oil in 2 mT in a single transient. The sensitivity of this system has also allowed the detection of proton NMR at magnetic fields as low as 0.059 mT, which is comparable to the Earth?s field. Such results make possible a number of new experiments in magnetic resonance imaging (MRI. We present a two-dimensional image of a phantom filled with mineral oil obtained in a field of 2 mT.

  20. Optical Fiber High Temperature Sensor Instrumentation for Energy Intensive Industries

    Energy Technology Data Exchange (ETDEWEB)

    Cooper, Kristie L.; Wang, Anbo; Pickrell, Gary R.

    2006-11-14

    This report summarizes technical progress during the program “Optical Fiber High Temperature Sensor Instrumentation for Energy Intensive Industries”, performed by the Center for Photonics Technology of the Bradley Department of Electrical and Computer Engineering at Virginia Tech. The objective of this program was to use technology recently invented at Virginia Tech to develop and demonstrate the application of self-calibrating optical fiber temperature and pressure sensors to several key energy-intensive industries where conventional, commercially available sensors exhibit greatly abbreviated lifetimes due primarily to environmental degradation. A number of significant technologies were developed under this program, including • a laser bonded silica high temperature fiber sensor with a high temperature capability up to 700°C and a frequency response up to 150 kHz, • the world’s smallest fiber Fabry-Perot high temperature pressure sensor (125 x 20 μm) with 700°C capability, • UV-induced intrinsic Fabry-Perot interferometric sensors for distributed measurement, • a single crystal sapphire fiber-based sensor with a temperature capability up to 1600°C. These technologies have been well demonstrated and laboratory tested. Our work plan included conducting major field tests of these technologies at EPRI, Corning, Pratt & Whitney, and Global Energy; field validation of the technology is critical to ensuring its usefulness to U.S. industries. Unfortunately, due to budget cuts, DOE was unable to follow through with its funding commitment to support Energy Efficiency Science Initiative projects and this final phase was eliminated.

  1. High point for CERN and high-temperature superconductors

    CERN Multimedia

    2007-01-01

    Amalia Ballarino is named the Superconductor Industry Person of the year 2006. Amalia Ballarino showing a tape of high-superconducting material used for the LHC current leads.The CERN project leader for the high-temperature superconducting current leads for the LHC, Amalia Ballarino, has received the award for "Superconductor Industry Person of the Year". This award, the most prestigious international award in the development and commercialization of superconductors, is presented by the leading industry newsletter "Superconductor Week". Amalia Ballarino was selected from dozens of nominations from around the world by a panel of recognized leading experts in superconductivity. "It is a great honour for me," says Amalia Ballarino. "It has been many years of hard work, and it’s a great satisfaction to see that the work has been completed successfully." Amalia Ballarino has been working on high-temperature superconducting materials sin...

  2. High Molecular Weight Polybenzimidazole Membranes for High Temperature PEMFC

    DEFF Research Database (Denmark)

    Yang, Jingshuai; Cleemann, Lars Nilausen; Steenberg, T.

    2014-01-01

    tensile strength of 30.3 MPa at room temperature or 7.3 MPa at 130 °C and a proton conductivity of 0.14 S cm–1 at 160 °C. Fuel cell tests with H2 and air at 160 °C showed high open circuit voltage, power density and a low degradation rate of 1.5 μV h–1 at a constant load of 300 mA cm–2.......High temperature operation of proton exchange membrane fuel cells under ambient pressure has been achieved by using phosphoric acid doped polybenzimidazole (PBI) membranes. To optimize the membrane and fuel cells, high performance polymers were synthesized of molecular weights from 30 to 94 k...

  3. 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

  4. Apparatus for accurately measuring high temperatures

    Science.gov (United States)

    Smith, D.D.

    The present invention is a thermometer used for measuring furnace temperatures in the range of about 1800/sup 0/ to 2700/sup 0/C. The thermometer comprises a broadband multicolor thermal radiation sensor positioned to be in optical alignment with the end of a blackbody sight tube extending into the furnace. A valve-shutter arrangement is positioned between the radiation sensor and the sight tube and a chamber for containing a charge of high pressure gas is positioned between the valve-shutter arrangement and the radiation sensor. A momentary opening of the valve shutter arrangement allows a pulse of the high gas to purge the sight tube of air-borne thermal radiation contaminants which permits the radiation sensor to accurately measure the thermal radiation emanating from the end of the sight tube.

  5. Thermomechanics of composite structures under high temperatures

    CERN Document Server

    Dimitrienko, Yu I

    2016-01-01

    This pioneering book presents new models for the thermomechanical behavior of composite materials and structures taking into account internal physico-chemical transformations such as thermodecomposition, sublimation and melting at high temperatures (up to 3000 K). It is of great importance for the design of new thermostable materials and for the investigation of reliability and fire safety of composite structures. It also supports the investigation of interaction of composites with laser irradiation and the design of heat-shield systems. Structural methods are presented for calculating the effective mechanical and thermal properties of matrices, fibres and unidirectional, reinforced by dispersed particles and textile composites, in terms of properties of their constituent phases. Useful calculation methods are developed for characteristics such as the rate of thermomechanical erosion of composites under high-speed flow and the heat deformation of composites with account of chemical shrinkage. The author expan...

  6. High temperature dimensional reduction in Snyder space

    Directory of Open Access Journals (Sweden)

    K. Nozari

    2015-11-01

    Full Text Available In this paper, we formulate the statistical mechanics in Snyder space that supports the existence of a minimal length scale. We obtain the corresponding invariant Liouville volume which properly determines the number of microstates in the semiclassical regime. The results show that the number of accessible microstates drastically reduces at the high energy regime such that there is only one degree of freedom for a particle. Using the Liouville volume, we obtain the deformed partition function and we then study the thermodynamical properties of the ideal gas in this setup. Invoking the equipartition theorem, we show that 2/3 of the degrees of freedom freeze at the high temperature regime when the thermal de Broglie wavelength becomes of the order of the Planck length. This reduction of the number of degrees of freedom suggests an effective dimensional reduction of the space from 3 to 1 at the Planck scale.

  7. High temperature dimensional reduction in Snyder space

    Science.gov (United States)

    Nozari, K.; Hosseinzadeh, V.; Gorji, M. A.

    2015-11-01

    In this paper, we formulate the statistical mechanics in Snyder space that supports the existence of a minimal length scale. We obtain the corresponding invariant Liouville volume which properly determines the number of microstates in the semiclassical regime. The results show that the number of accessible microstates drastically reduces at the high energy regime such that there is only one degree of freedom for a particle. Using the Liouville volume, we obtain the deformed partition function and we then study the thermodynamical properties of the ideal gas in this setup. Invoking the equipartition theorem, we show that 2/3 of the degrees of freedom freeze at the high temperature regime when the thermal de Broglie wavelength becomes of the order of the Planck length. This reduction of the number of degrees of freedom suggests an effective dimensional reduction of the space from 3 to 1 at the Planck scale.

  8. High temperature lined conduits, elbows and tees

    Science.gov (United States)

    De Feo, Angelo; Drewniany, Edward

    1982-01-01

    A high temperature lined conduit comprising, a liner, a flexible insulating refractory blanket around and in contact with the liner, a pipe member around the blanket and spaced therefrom, and castable rigid refractory material between the pipe member and the blanket. Anchors are connected to the inside diameter of the pipe and extend into the castable material. The liner includes male and female slip joint ends for permitting thermal expansion of the liner with respect to the castable material and the pipe member. Elbows and tees of the lined conduit comprise an elbow liner wrapped with insulating refractory blanket material around which is disposed a spaced elbow pipe member with castable refractory material between the blanket material and the elbow pipe member. A reinforcing band is connected to the elbow liner at an intermediate location thereon from which extend a plurality of hollow tubes or pins which extend into the castable material to anchor the lined elbow and permit thermal expansion. A method of fabricating the high temperature lined conduit, elbows and tees is also disclosed which utilizes a polyethylene layer over the refractory blanket after it has been compressed to maintain the refractory blanket in a compressed condition until the castable material is in place. Hot gases are then directed through the interior of the liner for evaporating the polyethylene and setting the castable material which permits the compressed blanket to come into close contact with the castable material.

  9. A nanocrystalline Sm-Co compound for high-temperature permanent magnets.

    Science.gov (United States)

    Zhang, Zhexu; Song, Xiaoyan; Qiao, Yinkai; Xu, Wenwu; Zhang, Jiuxing; Seyring, Martin; Rettenmayr, Markus

    2013-03-21

    The inherently high magnetic anisotropy and nanoscale grain size in a Sm5Co19 compound result in an intrinsic coercivity far higher than those of known Sm-Co compounds prior to orientation treatment. The combination of ultrahigh intrinsic coercivity, high Curie temperature and low coercivity temperature coefficient of nanocrystalline Sm5Co19 as a single phase material shows it to be a very promising compound to develop outstanding high-temperature permanent magnets.

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

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Lisa

    2002-03-07

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

  11. Temperature-dependent ordering phenomena in single crystals of germanium antimony tellurides

    Energy Technology Data Exchange (ETDEWEB)

    Urban, Philipp [Faculty of Chemistry and Mineralogy, Leipzig University, Scharnhorststr. 20, 04275 Leipzig (Germany); Schneider, Matthias N. [Department of Chemistry, LMU Munich, Butenandtstr. 5-13 (D), 81377 Munich (Germany); Oeckler, Oliver, E-mail: oliver.oeckler@gmx.de [Faculty of Chemistry and Mineralogy, Leipzig University, Scharnhorststr. 20, 04275 Leipzig (Germany)

    2015-07-15

    The temperature-dependent behavior of quenched single-crystalline (GeTe){sub n}Sb{sub 2}Te{sub 3} (n~2.8, n~5 and n~11) was investigated by semiquantitative modeling of diffuse X-ray scattering. The structure at room temperature exhibits trigonal twin domains, each comprising a stacking-disordered sequence of distorted rocksalt-type slabs with variable thicknesses. Ge and Sb share the cation position and vacancies are partially ordered in defect layers (van der Waals gaps) between the slabs. The average structure determined with resonant diffraction data corresponds to a rocksalt-type structure whose cation position is split along the stacking direction. Upon heating, cation ordering leads to a metastable superstructure of the rocksalt type at ~400 °C, which transforms to a rocksalt-type high-temperature phase with randomly distributed cations and vacancies at ~500 °C; this structure was also refined using resonant diffraction. Cooling at high or intermediate rates does not yield the long-range ordered phase, but directly leads to the twinned disordered phase. - Graphical abstract: Development of the diffraction patterns of (GeTe){sub ~11}Sb{sub 2}Te{sub 3} upon heating; the insets symbolically sketch the real structure at the corresponding temperatures. - Highlights: • The structure of disordered (GeTe){sub n}Sb{sub 2}Te{sub 3} is described as a function of temperature. • Structural changes are tracked by modeling diffuse X-ray scattering. • Quenched crystals exhibit distorted NaCl-type slabs with different thicknesses. • Vacancy ordering upon heating leads to a metastable superstructure of the NaCl type. • Further heating leads to an undistorted disordered NaCl-type high-temperature phase.

  12. An explanation of the irreversibility behavior in the highly- anisotropic high-temperature superconductors

    International Nuclear Information System (INIS)

    Gray, K.E.; Kim, D.H.

    1991-01-01

    The wide temperature range of the reversible, lossy state of the new high-temperature superconductors in a magnetic field was recognized soon after their discovery. This behavior, which had gone virtually undetected in conventional superconductors, has generated considerable interest, both for a fundamental understanding of the HTS and because it degrades the performance of HTS for finite-field applications. We show that recently proposed explanation of this behavior for the highly-anisotropic high-temperature superconductors, as a dimensional crossover of the magnetic vortices, is strongly supported by recent experiments on a Bi 2 Sr 2 CaCu 2 O x single crystal using the high-Q mechanical oscillator techniques

  13. Effect of microstructure on the high temperature strength of nitride

    Indian Academy of Sciences (India)

    Effect of microstructure on the high temperature strength of nitride bonded silicon carbide composite. J Rakshit P K Das. Composites Volume ... The effect of these parameters on room temperature and high temperature strength of the composite up to 1300°C in ambient condition were studied. The high temperature flexural ...

  14. Analysis of artificial fireplace logs by high temperature gas chromatography.

    Science.gov (United States)

    Kuk, Raymond J

    2002-11-01

    High temperature gas chromatography is used to analyze the wax of artificial fireplace logs (firelogs). Firelogs from several different manufacturers are studied and compared. This study shows that the wax within a single firelog is homogeneous and that the wax is also uniform throughout a multi-firelog package. Different brands are shown to have different wax compositions. Firelogs of the same brand, but purchased in different locations, also have different wax compositions. With this information it may be possible to associate an unknown firelog sample to a known sample, but a definitive statement of the origin cannot be made.

  15. ELOCA: fuel element behaviour during high temperature transients

    International Nuclear Information System (INIS)

    Sills, H.E.

    1979-03-01

    The ELOCA computer code was developed to simulate the uniform thermal-mechanical behaviour of a fuel element during high-temperature transients such as a loss-of-coolant accident (LOCA). Primary emphasis is on the diametral expansion of the fuel sheath. The model assumed is a single UO2/zircaloy-clad element with axisymmetric properties. Physical effects considered by the code are fuel expansion, cracking and melting; variation, during the transient, of internal gas pressure; changing fuel/sheath heat transfer; thermal, elastic and plastic sheath deformation (anisotropic); Zr/H 2 O chemical reaction effects; and beryllium-assisted crack penetration of the sheath. (author)

  16. 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

  17. Potential aerospace applications of high temperature superconductors

    Science.gov (United States)

    Selim, Raouf

    1994-12-01

    The recent discovery of High Temperature Superconductors (HTS) with superconducting transition temperature, T(sub c), above the boiling point of liquid nitrogen has opened the door for using these materials in new and practical applications. These materials have zero resistance to electric current, have the capability of carrying large currents and as such have the potential to be used in high magnetic field applications. One of the space applications that can use superconductors is electromagnetic launch of payloads to low-earth-orbit. An electromagnetic gun-type launcher can be used in small payload systems that are launched at very high velocity, while sled-type magnetically levitated launcher can be used to launch larger payloads at smaller velocities. Both types of launchers are being studied by NASA and the aerospace industry. The use of superconductors will be essential in any of these types of launchers in order to produce the large magnetic fields required to obtain large thrust forces. Low Temperature Superconductor (LTS) technology is mature enough and can be easily integrated in such systems. As for the HTS, many leading companies are currently producing HTS coils and magnets that potentially can be mass-produced for these launchers. It seems that designing and building a small-scale electromagnetic launcher is the next logical step toward seriously considering this method for launching payloads into low-earth-orbit. A second potential application is the use of HTS to build sensitive portable devices for the use in Non Destructive Evaluation (NDE). Superconducting Quantum Interference Devices (SQUID's) are the most sensitive instruments for measuring changes in magnetic flux. By using HTS in SQUID's, one will be able to design a portable unit that uses liquid nitrogen or a cryocooler pump to explore the use of gradiometers or magnetometers to detect deep cracks or corrosion in structures. A third use is the replacement of Infra-Red (IR) sensor leads on

  18. Lattice QCD at High Temperature and Density

    Science.gov (United States)

    Rebhan, Anton

    The theoretical framework for describing ultrarelativistically hot and dense matter is quantum field theory at finite temperature and density. At sufficiently high temperatures and densities, asymptotic freedom should make it possible to describe even the fundamental theory of strong interactions, quantum chromodynamics (QCD), through analytical and mostly perturbative means. This article tries to cover both principal issues related to gauge freedom as well as specific problems of thermal perturbation theory in non-Abelian gauge theories. After a brief review of the imaginary- and real-time formalisms of thermal field theory, the latter is extended to gauge theories. Aspects of different treatments of Faddeev-Popov ghosts and different gauge choices are discussed for general non-Abelian gauge theories, both in the context of path integrals and in covariant operator quantization. The dependence of the formalism on the gauge-fixing parameters introduced in perturbation theory is investigated in detail. Only the partition function and expectation values of gauge-invariant observables are entirely gauge independent. Beyond those it is shown that the location of singularities of gauge and matter propagators, which define screening behaviour and dispersion laws of the corresponding quasi-particle excitations, are gauge independent when calculated systematically.

  19. Pressure sensor for high-temperature liquids

    International Nuclear Information System (INIS)

    1980-01-01

    A pressure sensor for use with liquid metals (eg Na and K) over the pressure range 0 - 2MPa and temperature range 644 - 922'K is described. A soft diaphragm is exposed on one side to the fluid (liquid metal) and on the other to a first source of gas at a first gas pressure. A stiff diaphragm is exposed on one side to the first gas source and on the other side by a second source of gas at a second pressure. The stiff diaphragm is in pushing engagement with the soft diaphragm such that movement is transmitted to the stiff diaphragm when the pressure in the fluid exceeds the first and second gas pressures. The displacement of the stiff diaphragm is measured and is a function of the fluid pressure. Details of the measuring means are given. A version for insertion in a wall of a container to measure pressure in high temperature liquid metals in the container is described. It comprises an annular bellows connected by an outer peripheral edge to the wall of the container, a stiff disc connected at an outer edge to an inner edge of the bellows and forming therewith a soft diaphragm. The operation is similar to that previously described. Full details are given. (U.K.)

  20. Single-atom reversible recording at room temperature

    DEFF Research Database (Denmark)

    Quaade, Ulrich; Stokbro, Kurt; Lin, Rong

    2001-01-01

    investigate two important aspects of using this single-atom switch as a memory device. First, the switching is electron stimulated, and through detailed modelling the switching probability per electron is accurately deduced. Second, we have investigated the possibilities for desorbing single hydrogen atoms...... to construct ordered arrays of switches to manufacture a memory device. Two desorption mechanisms have been considered: the well known electron-induced desorption at negative sample bias and a novel mechanism probably involving elastic deformation of the tip. For both mechanisms mechanical stability of the STM...... is of crucial importance. With our equipment it was possible to create a row of four switches in a controlled way.(Some figures in this article are in colour only in the electronic version)....

  1. High-temperature superconducting nanowires for photon detection

    Energy Technology Data Exchange (ETDEWEB)

    Arpaia, R. [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, S-41296 Göteborg (Sweden); CNR SPIN Institute – Superconductors, Innovative Materials and Devices, UOS–Napoli, I-80100 Napoli (Italy); Dipartimento di Fisica, Università degli Studi di Napoli ‘Federico II’, I-80125 Napoli (Italy); Ejrnaes, M. [CNR SPIN Institute – Superconductors, Innovative Materials and Devices, UOS–Napoli, I-80100 Napoli (Italy); Parlato, L. [CNR SPIN Institute – Superconductors, Innovative Materials and Devices, UOS–Napoli, I-80100 Napoli (Italy); Dipartimento di Fisica, Università degli Studi di Napoli ‘Federico II’, I-80125 Napoli (Italy); Tafuri, F. [CNR SPIN Institute – Superconductors, Innovative Materials and Devices, UOS–Napoli, I-80100 Napoli (Italy); Dipartimento di Ingegneria Industriale e dell’Informazione, Seconda Università di Napoli, I-81031 Aversa, CE (Italy); Cristiano, R. [CNR SPIN Institute – Superconductors, Innovative Materials and Devices, UOS–Napoli, I-80100 Napoli (Italy); Golubev, D. [Low Temperature Laboratory (OVLL), Aalto University School of Science, P.O. Box 13500, FI-00076 Aalto (Finland); Sobolewski, Roman, E-mail: roman.sobolewski@rochester.edu [Institute of Electron Technology, PL-02668 Warszawa (Poland); Department of Electrical and Computer Engineering and Laboratory for Laser Energetics, University of Rochester, NY 14627-0231 (United States); Bauch, T.; Lombardi, F. [Quantum Device Physics Laboratory, Department of Microtechnology and Nanoscience, Chalmers University of Technology, S-41296 Göteborg (Sweden); and others

    2015-02-15

    Highlights: • Homogeneous YBCO nanowires have been fabricated for photon detection applications. • Serial-parallel nanowire configuration leads to a large detector active area. • The YBCO nanowires exhibit critical current densities up to 106 A/cm{sup 2}. • The devices have been excited using a 1550-nm wavelength, pulsed laser irradiation. • Photoresponse signals have been measured and analyzed from 4 K up to the device T{sub c}. - Abstract: The possible use of high-temperature superconductors (HTS) for realizing superconducting nanowire single-photon detectors is a challenging, but also promising, aim because of their ultrafast electron relaxation times and high operating temperatures. The state-of-the-art HTS nanowires with a 50-nm thickness and widths down to 130 nm have been fabricated and tested under a 1550-nm wavelength laser irradiation. Experimental results presenting both the amplitude and rise times of the photoresponse signals as a function of the normalized detector bias current, measured in a wide temperature range, are discussed. The presence of two distinct regimes in the photoresponse temperature dependence is clearly evidenced, indicating that there are two different response mechanisms responsible for the HTS photoresponse mechanisms.

  2. High spatial resolution spectroscopy of single semiconductor nanostructures

    Science.gov (United States)

    Harris, T. D.; Gershoni, D.; Pfeiffer, L.; Nirmal, M.; Trautman, J. K.; Macklin, J. J.

    1996-11-01

    Low-temperature near-field scanning optical microscopy is used for the first time in spectroscopic studies of single, nanometre dimension, cleaved edge overgrown quantum wires. A direct experimental comparison between a two-dimensional system and a single genuinely one-dimensional quantum wire system, inaccessible to conventional far-field optical spectroscopy, is enabled by the enhanced spatial resolution. We show that the photoluminescence of a single quantum wire is easily distinguished from that of the surrounding quantum well. Emission from localized centres is shown to dominate the photoluminescence from both wires and wells at low temperatures. A factor of three oscillator strength enhancement for these wires compared with the wells is concluded from the photoluminescence excitation data. We also report room-temperature spectroscopy and dynamics of single CdSe nanocrystals. Photochemistry, trap dynamics and spectroscopy are easily determined.

  3. Fast pyrolysis of biomass at high temperatures

    DEFF Research Database (Denmark)

    Trubetskaya, Anna

    on the electron energy loss spectroscopy (EELS) analysis. In contrast to expectations of graphitic structures to react slower than amorphous samples, beechwood andwheat straw soot were 35 and 571 times more reactive than pinewood soot prepared at 1400°C.The presence of potassium in wheat straw soot mainly...... pyrolysis at high temperatures plays a significant role in the overall combustion process since the biomass type, the reaction kinetics and heat transfer rates during pyrolysis influence the volatile gas release. The solid residue yield and its properties in suspension firing, including particle size...... that potassium has a dominating effect on the soot reactivity compared to nanostructure and particle size. A mathematical model of biomass fast pyrolysis was developed to predict the gas and char yield of wood and herbaceous biomass at heating rates > 600K s-1. The model includes both kinetics and external...

  4. Robust high temperature oxygen sensor electrodes

    DEFF Research Database (Denmark)

    Lund, Anders

    Platinum is the most widely used material in high temperature oxygen sensor electrodes. However, platinum is expensive and the platinum electrode may, under certain conditions, suffer from poisoning, which is detrimental for an oxygen sensor. The objective of this thesis is to evaluate electrode...... materials as candidates for robust oxygen sensor electrodes. The present work focuses on characterising the electrochemical properties of a few electrode materials to understand which oxygen electrode processes are limiting for the response time of the sensor electrode. Three types of porous platinum......-Dansensor. The electrochemical properties of the electrodes were characterised by electrochemical impedance spectroscopy (EIS), and the structures were characterised by x-ray diffraction and electron microscopy. At an oxygen partial pressures of 0.2 bar, the response time of the sensor electrode was determined by oxygen...

  5. High Temperature Polymer Electrolyte Fuel Cells

    DEFF Research Database (Denmark)

    Fleige, Michael

    This thesis presents the development and application of electrochemical half-cell setups to study the catalytic reactions taking place in High Temperature Polymer Electrolyte Fuel Cells (HTPEM-FCs): (i) a pressurized electrochemical cell with integrated magnetically coupled rotating disk electrode...... at potentials, which approach the usual cathode potentials of HTPEM-FCs. Therefore, it seems that H3PO4-based fuel cells are not much suited to efficiently convert ethanol in accordance with findings in earlier research papers. Given that HTPEM-FCs can tolerate CO containing reformate gas, focusing research...... activities on catalysts for reformate oxidation appears more rational. Improvements of the ORR activity at the cathode can have large influence on the performance of HTPEM-FCs. The measurements of oxygen diffusivity and solubility contribute to the understanding of oxygen mass transport at the interface...

  6. High temperature chemically resistant polymer concrete

    Science.gov (United States)

    Sugama, T.; Kukacka, L.E.

    High temperature chemically resistant, non-aqueous polymer concrete composites consist of about 12 to 20% by weight of a water-insoluble polymer binder. The binder is polymerized in situ from a liquid vinyl-type monomer or mixture of vinyl containing monomers such as triallylcyanurate, styrene, acrylonitrile, acrylamide, methacrylamide, methyl-methacrylate, trimethylolpropane trimethacrylate and divinyl benzene. About 5 to 40% by weight of a reactive inorganic filler selected from the group consisting of tricalcium silicate and dicalcium silicate and mixtures containing less than 2% free lime, and about 48 to 83% by weight of silica sand/ and a free radical initiator such as di-tert-butyl peroxide, azobisisobutyronitrile, benzoyl peroxide, lauryl peroxide, other orgaic peroxides and combinations to initiate polymerization of the monomer in the presence of the inorganic filers are used.

  7. High Temperature Particle Filtration Technology; TOPICAL

    International Nuclear Information System (INIS)

    Besmann, T.M.

    2001-01-01

    High temperature filtration can serve to improve the economic, environmental, and energy performance of chemical processes. This project was designed to evaluate the stability of filtration materials in the environments of the production of dimethyldichlorosilane (DDS). In cooperation with Dow Corning, chemical environments for the fluidized bed reactor where silicon is converted to DDS and the incinerator where vents are cornbusted were characterized. At Oak Ridge National Laboratory (ORNL) an exposure system was developed that could simulate these two environments. Filter samples obtained from third parties were exposed to the environments for periods up to 1000 hours. Mechanical properties before and after exposure were determined by burst-testing rings of filter material. The results indicated that several types of filter materials would likely perform well in the fluid bed environment, and two materials would be good candidates for the incinerator environment

  8. High temperature coatings for gas turbines

    Science.gov (United States)

    Zheng, Xiaoci Maggie

    2003-10-21

    Coating for high temperature gas turbine components that include a MCrAlX phase, and an aluminum-rich phase, significantly increase oxidation and cracking resistance of the components, thereby increasing their useful life and reducing operating costs. The aluminum-rich phase includes aluminum at a higher concentration than aluminum concentration in the MCrAlX alloy, and an aluminum diffusion-retarding composition, which may include cobalt, nickel, yttrium, zirconium, niobium, molybdenum, rhodium, cadmium, indium, cerium, iron, chromium, tantalum, silicon, boron, carbon, titanium, tungsten, rhenium, platinum, and combinations thereof, and particularly nickel and/or rhenium. The aluminum-rich phase may be derived from a particulate aluminum composite that has a core comprising aluminum and a shell comprising the aluminum diffusion-retarding composition.

  9. The Integrity of ACSR Full Tension Single-Stage Splice Connector at Higher Operation Temperature

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jy-An John [ORNL; Lara-Curzio, Edgar [ORNL; King Jr, Thomas J [ORNL

    2008-10-01

    Due to increases in power demand and limited investment in new infrastructure, existing overhead power transmission lines often need to operate at temperatures higher than those used for the original design criteria. This has led to the accelerated aging and degradation of splice connectors. It is manifested by the formation of hot-spots that have been revealed by infrared imaging during inspection. The implications of connector aging is two-fold: (1) significant increases in resistivity of the splice connector (i.e., less efficient transmission of electricity) and (2) significant reductions in the connector clamping strength, which could ultimately result in separation of the power transmission line at the joint. Therefore, the splice connector appears to be the weakest link in electric power transmission lines. This report presents a protocol for integrating analytical and experimental approaches to evaluate the integrity of full tension single-stage splice connector assemblies and the associated effective lifetime at high operating temperature.

  10. Thermal expansion, anharmonicity and temperature-dependent Raman spectra of single- and few-layer MoSe₂ and WSe₂.

    Science.gov (United States)

    Late, Dattatray J; Shirodkar, Sharmila N; Waghmare, Umesh V; Dravid, Vinayak P; Rao, C N R

    2014-06-06

    We report the temperature-dependent Raman spectra of single- and few-layer MoSe2 and WSe2 in the range 77-700 K. We observed linear variation in the peak positions and widths of the bands arising from contributions of anharmonicity and thermal expansion. After characterization using atomic force microscopy and high-resolution transmission electron microscopy, the temperature coefficients of the Raman modes were determined. Interestingly, the temperature coefficient of the A(2)(2u) mode is larger than that of the A(1g) mode, the latter being much smaller than the corresponding temperature coefficients of the same mode in single-layer MoS2 and of the G band of graphene. The temperature coefficients of the two modes in single-layer MoSe2 are larger than those of the same modes in single-layer WSe2. We have estimated thermal expansion coefficients and temperature dependence of the vibrational frequencies of MoS2 and MoSe2 within a quasi-harmonic approximation, with inputs from first-principles calculations based on density functional theory. We show that the contrasting temperature dependence of the Raman-active mode A(1g) in MoS2 and MoSe2 arises essentially from the difference in their strain-phonon coupling. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Assessment of high-temperature battery systems

    Energy Technology Data Exchange (ETDEWEB)

    Sen, R K

    1989-02-01

    Three classes of high-temperature batteries are being developed internationally with transportation and stationary energy storage applications in mind: sodium/sulfur, lithium/metal sulfide, and sodium/metal chloride. Most attention is being given to the sodium/sulfur system. The Office of Energy Storage and Distribution (OESD) and the Office of Transportation Systems (OTS) of the US Department of Energy (DOE) are actively supporting the development of this battery system. It is anticipated that pilot-scale production facilities for sodium/sulfur batteries will be in operation in the next couple of years. The lithium/metal sulfide and the sodium/metal chloride systems are not receiving the same level of attention as the sodium/sulfur battery. Both of these systems are in an earlier stage of development than sodium/sulfur. OTS and OESD are supporting work on the lithium/iron sulfide battery in collaboration with the Electric Power Research Institute (EPRI); the work is being carried out at Argonne National Laboratory (ANL). The sodium/metal chloride battery, the newest member of the group, is being developed by a Consortium of South African and British companies. Very little DOE funds are presently allocated for research on this battery. The purpose of this assessment is to evaluate the present status of the three technologies and to identify for each technology a prioritized list of R and D issues. Finally, the assessment includes recommendations to DOE for a proposed high-temperature battery research and development program. 18 figs., 21 tabs.

  12. Phase diagrams of high temperature and high density QCD

    International Nuclear Information System (INIS)

    Fukushima, Kenji

    2012-01-01

    It is extremely difficult to solve QCD non-perturbatively in general, but at very high temperature and pressure perturbative calculation becomes possible to a certain extent, and it is possible to find out the nontrivial vacuum structure more or less. It is not necessarily a dream anymore at present to investigate the phase structure from the QCD itself, but it is rather general to discuss the phase transitions and the phase structures on the basis of effective models haring the global symmetry in common. It is indispensable to understand the QCD calculations to know the applicability of the models, since various experience obtained in the study of the perturbative calculations are reflected there. At first the finite temperature field theory is introduced. The calculation of grand distribution function Z is described in detail. Then finite temperature Yang-Mills theory is taken up. Finally finite temperature quark effect is studied. Within the limited space of the present note farther descriptions are spared. But it is necessary to go further by constructing the Polyakov loop potential to describe the extended Weiss potentials non-perturbatively for the proper deconfined phase transitions. And it is necessary to assume the setup of the model to break the chiral symmetry spontaneously and so on. (S. Funahashi)

  13. Josephson noise thermometry with high temperature superconducting devices

    CERN Document Server

    Peden, D A

    2000-01-01

    High Temperature Superconducting devices for absolute Noise Thermometry are under development for the measurement of temperature in the 10-50 K range. This Thesis is concerned with two complementary methods which have been developed in parallel. The first technique, Josephson Linewidth Thermometry, uses a HTS Josephson junction shunted by a low resistance noble metal resistor. The conversion of thermal voltage fluctuations via the ac Josephson effect results in thermal broadening of the Josephson oscillation linewidth. Single and double junction HTS R-SQUIDs have been fabricated where a shunt resistance approx 25 mu OMEGA has been achieved. In the double junction R-SQUIDs, where the voltage across the terminals is modulated at the Josephson heterodyne frequency, the first reported observations of Josephson heterodyne oscillations in HTS R-SQUIDs have been made and the linearity of the voltage-frequency relationship established. The second approach, known as the Quantum Roulette Noise Thermometer, uses the the...

  14. Applications of high-temperature superconductors in power technology

    International Nuclear Information System (INIS)

    Hull, John R

    2003-01-01

    Since the discovery of the first high-temperature superconductors (HTSs) in the late 1980s, many materials and families of materials have been discovered that exhibit superconductivity at temperatures well above 20 K. Of these, several families of HTSs have been developed for use in electrical power applications. Demonstration of devices such as motors, generators, transmission lines, transformers, fault-current limiters, and flywheels in which HTSs and bulk HTSs have been used has proceeded to ever larger scales. First-generation wire, made from bismuth-based copper oxides, was used in many demonstrations. The rapid development of second-generation wire, made by depositing thin films of yttrium-based copper oxide on metallic substrates, is expected to further accelerate commercial applications. Bulk HTSs, in which large single-grain crystals are used as basic magnetic components, have also been developed and have potential for electrical power applications

  15. A constitutive model with damage for high temperature superalloys

    Science.gov (United States)

    Sherwood, J. A.; Stouffer, D. C.

    1988-01-01

    A unified constitutive model is searched for that is applicable for high temperature superalloys used in modern gas turbines. Two unified inelastic state variable constitutive models were evaluated for use with the damage parameter proposed by Kachanov. The first is a model (Bodner, Partom) in which hardening is modeled through the use of a single state variable that is similar to drag stress. The other (Ramaswamy) employs both a drag stress and back stress. The extension was successful for predicting the tensile, creep, fatigue, torsional and nonproportional response of Rene' 80 at several temperatures. In both formulations, a cumulative damage parameter is introduced to model the changes in material properties due to the formation of microcracks and microvoids that ultimately produce a macroscopic crack. A back stress/drag stress/damage model was evaluated for Rene' 95 at 1200 F and is shown to predict the tensile, creep, and cyclic loading responses reasonably well.

  16. 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

  17. Two decades on[Research into high-temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Durrani, M. [Physics World (United Kingdom)

    2006-04-15

    Research into high-temperature superconductors should focus on experiment, not theory. While the world looked on in horror at the events unfolding at the Chernobyl nuclear-power plant in the Soviet Union 20 years ago this month, another significant - but far less reported - development in the world of physics had just taken place. On 17 April 1986 a short paper by Georg Bednorz and Alexander Mueller arrived at the offices of Zeitschrift fuer Physik in Heidelberg, Germany. The two physicists, based at IBM's Zurich Research Laboratory in Switzerland, announced they had made a material from barium, lanthanum, copper and oxygen that could conduct electricity without resistance when cooled below a transition temperature, T{sub c}, of about 30 K. It was the world's first 'high-temperature' superconductor. Driven by the dream of materials that can superconduct at room temperature, experimentalists scurried back to their labs. Within a year, a T{sub c} of 90 K in another material had been reported and by October 1987 Bednorz and Mueller had been crowned with a Nobel prize. While papers on high-temperature superconductivity have continued to stream out since those heady days, progress has been slower than expected. Applications like levitating trains and resistance-free power cables are only now starting to come to market. Scientists have been unable to make superconducting wires that work much above 130 K, while a reliable theory of high-temperature superconductivity remains elusive. Even if we had such a theory, it is not clear that it would predict which materials might superconduct at room temperature. After all, the Bardeen-Cooper-Schrieffer theory, which explains the behaviour of low-temperature superconductors with admirable success, said nothing about the superconducting properties of Bednorz and Mueller's copper-oxide ceramics. What successes there have been over the last 20 years - such as the recent discoveries that iron, single crystals

  18. Fiber Optic Temperature Sensor Insert for High Temperature Environments

    Science.gov (United States)

    Black, Richard James (Inventor); Costa, Joannes M. (Inventor); Moslehi, Behzad (Inventor); Zarnescu, Livia (Inventor)

    2017-01-01

    A thermal protection system (TPS) test plug has optical fibers with FBGs embedded in the optical fiber arranged in a helix, an axial fiber, and a combination of the two. Optionally, one of the optical fibers is a sapphire FBG for measurement of the highest temperatures in the TPS plug. The test plug may include an ablating surface and a non-ablating surface, with an engagement surface with threads formed, the threads having a groove for placement of the optical fiber. The test plug may also include an optical connector positioned at the non-ablating surface for protection of the optical fiber during insertion and removal.

  19. 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

  20. Assessment of microelectronics packaging for high temperature, high reliability applications

    Energy Technology Data Exchange (ETDEWEB)

    Uribe, F.

    1997-04-01

    This report details characterization and development activities in electronic packaging for high temperature applications. This project was conducted through a Department of Energy sponsored Cooperative Research and Development Agreement between Sandia National Laboratories and General Motors. Even though the target application of this collaborative effort is an automotive electronic throttle control system which would be located in the engine compartment, results of this work are directly applicable to Sandia`s national security mission. The component count associated with the throttle control dictates the use of high density packaging not offered by conventional surface mount. An enabling packaging technology was selected and thermal models defined which characterized the thermal and mechanical response of the throttle control module. These models were used to optimize thick film multichip module design, characterize the thermal signatures of the electronic components inside the module, and to determine the temperature field and resulting thermal stresses under conditions that may be encountered during the operational life of the throttle control module. Because the need to use unpackaged devices limits the level of testing that can be performed either at the wafer level or as individual dice, an approach to assure a high level of reliability of the unpackaged components was formulated. Component assembly and interconnect technologies were also evaluated and characterized for high temperature applications. Electrical, mechanical and chemical characterizations of enabling die and component attach technologies were performed. Additionally, studies were conducted to assess the performance and reliability of gold and aluminum wire bonding to thick film conductor inks. Kinetic models were developed and validated to estimate wire bond reliability.

  1. High temperature superconductors at optimal doping

    Directory of Open Access Journals (Sweden)

    W. E. Pickett

    2006-09-01

    Full Text Available   Intensive study of the high temperature superconductors has been ongoing for two decades. A great deal of this effort has been devoted to the underdoped regime, where the new and difficult physics of the doped Mott insulator has met extra complications including bilayer coupling/splitting, shadow bands, and hot spots. While these complications continue to unfold, in this short overview the focus is moved to the region of actual high-Tc, that of optimal doping. The focus here also is not on the superconducting state itself, but primarily on the characteristics of the normal state from which the superconducting instability arises, and even these can be given only a broad-brush description. A reminder is given of two issues,(i why the “optimal Tc” varies,for n-layered systems it increases for n up to 3, then decreases for a given n, Tc increases according to the ‘basis’ atom in the order Bi, Tl, Hg (ii how does pressure, or a particular uniaxial strain, increase Tc when the zero-strain system is already optimally doped?

  2. Nuclear graphite for high temperature reactors

    International Nuclear Information System (INIS)

    Marsden, B.J.

    2001-01-01

    The cores and reflectors in modern High Temperature Gas Cooled Reactors (HTRs) are constructed from graphite components. There are two main designs; the Pebble Bed design and the Prism design. In both of these designs the graphite not only acts as a moderator, but is also a major structural component that may provide channels for the fuel and coolant gas, channels for control and safety shut off devices and provide thermal and neutron shielding. In addition, graphite components may act as a heat sink or conduction path during reactor trips and transients. During reactor operation, many of the graphite component physical properties are significantly changed by irradiation. These changes lead to the generation of significant internal shrinkage stresses and thermal shut down stresses that could lead to component failure. In addition, if the graphite is irradiated to a very high irradiation dose, irradiation swelling can lead to a rapid reduction in modulus and strength, making the component friable.The irradiation behaviour of graphite is strongly dependent on its virgin microstructure, which is determined by the manufacturing route. Nevertheless, there are available, irradiation data on many obsolete graphites of known microstructures. There is also a well-developed physical understanding of the process of irradiation damage in graphite. This paper proposes a specification for graphite suitable for modern HTRs. (author)

  3. Study Progress of Physiological Responses in High Temperature Environment

    Science.gov (United States)

    Li, K.; Zheng, G. Z.; Bu, W. T.; Wang, Y. J.; Lu, Y. Z.

    2017-10-01

    Certain workers are exposed to high temperatures for a long time. Heat stress will result in a series of physiological responses, and cause adverse effects on the health and safety of workers. This paper summarizes the physiological changes of cardiovascular system, core temperature, skin temperature, water-electrolyte metabolism, alimentary system, neuroendocrine system, reaction time and thermal fatigue in high temperature environments. It can provide a theoretical guidance for labor safety in high temperature environment.

  4. Structural instabilities of high temperature alloys and their use in advanced high temperature gas cooled reactors

    International Nuclear Information System (INIS)

    Schuster, H.; Ennis, P.J.; Nickel, H.; Czyrska-Filemonowicz, A.

    1989-01-01

    High-temperature, iron-nickel and nickel based alloys are the candidate heat exchanger materials for advanced high temperature gas-cooled reactors supplying process heat for coal gasification, where operation temperatures can reach 850-950 deg. C and service lives of more than 100,000 h are necessary. In the present paper, typical examples of structural changes which occur in two representative alloys (Alloy 800 H, Fe-32Ni-20Cr and Alloy 617, Ni-22Cr-12Co-9Mo-1Al) during high temperature exposure will be given and the effects on the creep rupture properties discussed. At service temperatures, precipitation of carbides occurs which has a significant effect on the creep behaviour, especially in the early stages of creep when the precipitate particles are very fine. During coarsening of the carbides, carbides at grain boundaries restrict grain boundary sliding which retards the development of creep damage. In the service environments, enhanced carbide precipitation may occur due to the ingress of carbon from the environment (carburization). Although the creep rate is not adversely affected, the ductility of the carburized material at low and intermediate temperatures is very low. During simulated service exposures, the formation of surface corrosion scales, the precipitation of carbides and the formation of internal oxides below the surface leads to depletion of the matrix in the alloying elements involved in the corrosion processes. In thin-walled tubes the depletion of Cr due to Cr 2 O 3 formation on the surface can lead to a loss of creep strength. An additional depletion effect resulting from environmental-metal reactions is the loss of carbon (decarburization) which may occur in specific environments. The compositions of the cooling gases which decarburize the material have been determined; they are to be avoided during reactor operation

  5. Single layer porous gold films grown at different temperatures

    International Nuclear Information System (INIS)

    Zhang Renyun; Hummelgard, Magnus; Olin, Hakan

    2010-01-01

    Large area porous gold films can be used in several areas including electrochemical electrodes, as an essential component in sensors, or as a conducting material in electronics. Here, we report on evaporation induced crystal growth of large area porous gold films at 20, 40 and 60 deg. C. The gold films were grown on liquid surface at 20 deg. C, while the films were grown on the wall of beakers when temperature increased to 40 and 60 deg. C. The porous gold films consisted of a dense network of gold nanowires as characterized by TEM and SEM. TEM diffraction results indicated that higher temperature formed larger crystallites of gold wires. An in situ TEM imaging of the coalescence of gold nanoparticles mimicked the process of the growth of these porous films, and a plotting of the coalescence time and the neck radius showed a diffusion process. The densities of these gold films were also characterized by transmittance, and the results showed film grown at 20 deg. C had the highest density, while the film grown at 60 deg. C had the lowest consistent with SEM and TEM characterization. Electrical measurements of these gold films showed that the most conductive films were the ones grown at 40 deg. C. The conductivities of the gold films were related to the amount of contamination, density and the diameter of the gold nanowires in the films. In addition, a gold film/gold nanoparticle hybrid was made, which showed a 10% decrease in transmittance during hybridization, pointing to applications as chemical and biological sensors.

  6. Anisotropic magnetoresistance and thermodynamic fluctuations in high-temperature superconductors

    International Nuclear Information System (INIS)

    Heine, G.

    1999-05-01

    Measurements of the in-plane and out-of-plane resistivity and the transverse and longitudinal in-plane and out-of-plane magnetoresistance above T, are reported in the high-temperature superconductors Bi2Sr2CaCu208+' and YBa2CU307 b . The carrier concentration of the Bi2Sr2CaCu208+' single crystals covers a broad range of the phase diagram from the slightly under doped to the moderately over doped region. The doping concentration of the thin films ranges from strongly under doped to optimally doped. The in-plane resistivities obey a metallic-like temperature dependence with a positive magnetoresistance in the transverse and the longitudinal orientation of the magnetic field. The out-of-plane resistivities show an activated behavior above T, with a metallic region at higher temperatures and negative magnetoresistance. The data were analyzed in the framework of a model for superconducting order parameter fluctuations. The positive in-plane magnetoresistance of the highly anisotropic Bi2Sr2CaCu208+x single crystals is interpreted as the suppression of the fluctuation-conductivity enhancement including orbital and spin contributions, whereas the negative magnetoresistance arises from the reduction of the fluctuation-induced pseudogap in the single-electron density-of-states by the magnetic field. For higher temperatures a transition to the normal-state magnetoresistance occurs for the in-plane transport. In the less anisotropic YBa2CU307 b thin films the positive out-of-plane magnetoresistance near T, changes sign to a negative magnetoresistance at higher temperatures. This behavior is also consistent with predictions from the theory of thermodynamic order-parameter fluctuations. The agreement of the fluctuation theory with the experimental findings is excellent for samples from the over doped side of the phase diagram, but deteriorate with decreasing carrier concentration. This behavior is interpreted by the dominating d-wave symmetry of the superconducting order

  7. Performance of High Temperature Operational Amplifier, Type LM2904WH, under Extreme Temperatures

    Science.gov (United States)

    Patterson, Richard; Hammoud, Ahmad; Elbuluk, Malik

    2008-01-01

    Operation of electronic parts and circuits under extreme temperatures is anticipated in NASA space exploration missions as well as terrestrial applications. Exposure of electronics to extreme temperatures and wide-range thermal swings greatly affects their performance via induced changes in the semiconductor material properties, packaging and interconnects, or due to incompatibility issues between interfaces that result from thermal expansion/contraction mismatch. Electronics that are designed to withstand operation and perform efficiently in extreme temperatures would mitigate risks for failure due to thermal stresses and, therefore, improve system reliability. In addition, they contribute to reducing system size and weight, simplifying its design, and reducing development cost through the elimination of otherwise required thermal control elements for proper ambient operation. A large DC voltage gain (100 dB) operational amplifier with a maximum junction temperature of 150 C was recently introduced by STMicroelectronics [1]. This LM2904WH chip comes in a plastic package and is designed specifically for automotive and industrial control systems. It operates from a single power supply over a wide range of voltages, and it consists of two independent, high gain, internally frequency compensated operational amplifiers. Table I shows some of the device manufacturer s specifications.

  8. New temperature monitoring devices for high-temperature irradiation experiments in the high flux reactor Petten

    Energy Technology Data Exchange (ETDEWEB)

    Laurie, M.; Futterer, M. A.; Lapetite, J. M. [European Commission Joint Research Centre, Institute for Energy, P.O. Box 2, NL-1755 ZG Petten (Netherlands); Fourrez, S. [THERMOCOAX SAS, BP 26, Planquivon, 61438 Flers Cedex (France); Morice, R. [Laboratoire National de Metrologie et d' Essais, 1 rue Gaston Boissier, 75724 Paris (France)

    2009-07-01

    Within the European High Temperature Reactor Technology Network (HTR-TN) and related projects a number of HTR fuel irradiations are planned in the High Flux Reactor Petten (HFR), The Netherlands, with the objective to explore the potential of recently produced fuel for even higher temperature and burn-up. Irradiating fuel under defined conditions to extremely high burn-ups will provide a better understanding of fission product release and failure mechanisms if particle failure occurs. After an overview of the irradiation rigs used in the HFR, this paper sums up data collected from previous irradiation tests in terms of thermocouple data. Some research and development work for further improvement of thermocouples and other on-line instrumentation will be outlined. (authors)

  9. 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...

  10. Thermoelectric Powered High Temperature Wireless Sensing

    Science.gov (United States)

    Kucukkomurler, Ahmet

    This study describes use of a thermoelectric power converter to transform waste heat into electrical energy to power an RF receiver and transmitter, for use in harsh environment wireless temperature sensing and telemetry. The sensing and transmitting module employs a DS-1820 low power digital temperature sensor to perform temperature to voltage conversion, an ATX-34 RF transmitter, an ARX-34 RF receiver module, and a PIC16f84A microcontroller to synchronize data communication between them. The unit has been tested in a laboratory environment, and promising results have been obtained for an actual automotive wireless under hood temperature sensing and telemetry implementation.

  11. Austenitic stainless steel for high temperature applications

    International Nuclear Information System (INIS)

    Johnson, G. D.; Powell, R. W.

    1985-01-01

    This invention describes a composition for an austenitic stainless steel which has been found to exhibit improved high temperature stress rupture properties. The composition of this alloy is about (in wt. %): 12.5 to 14.5 Cr; 14.5 to 16.5 Ni; 1.5 to 2.5 Mo; 1.5 to 2.5 Mn; 0.1 to 0.4 Ti; 0.02 to 0.08 C; 0.5 to 1.0 Si; 0.01 maximum, N; 0.02 to 0.008 P; 0.002 to 0.008 B; 0.004-0.0010 S; 0.02-0.05 Nb; 0.01-0.05 V; 0.005-0.02 Ta; 0.02-0.05 Al; 0.01-0.04 Cu; 0.02-0.05 Co; 0.03 maximum, As; 0.01 maximum, O; 0.01 maximum, Zr; and with the balance of the alloy being essentially iron. The carbon content of the alloy is adjusted such that wt. % Ti/(wt. % C+wt. % N) is between 4 and 6, and most preferably about 5. In addition the sum of the wt. % P+wt. % B+wt. % S is at least 0.03 wt. %. This alloy is believed to be particularly well suited for use as fast breeder reactor fuel element cladding

  12. Atomic processes in high temperature plasmas

    International Nuclear Information System (INIS)

    Hahn, Y.

    1991-07-01

    This is the final report on the project Atomic Processes in High Temperature Plasmas', which has been completed in June 30, 1991. The original contract started in 1978. The dielectronic recombination (DR) rate coefficients were calculated for ions with the number of electrons N = 1, 2, 3, 4, 5, 10, 11, and 12. The result was then used to construct a new and improved rate formula. Other important resonant processes, which are closely related to DR, were also studied to interpret experiments and to test the DR theory. The plasma field and the density effects on the rate coefficients was found to be important, and a consistent correction procedure is being developed. The available data on the DR rates and their accuracy do not yet fully meet the requirement for plasma modeling; there are serious gaps in the available data, and the currently adopted theoretical procedure needs improvements. Critical assessment of the current status of the DR problem is presented, and possible future work needed is summarized

  13. Electronic phase separation and high temperature superconductors

    International Nuclear Information System (INIS)

    Kivelson, S.A.

    1994-01-01

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

  14. Free energy of QCD at high temperature

    International Nuclear Information System (INIS)

    Braaten, E.; Nieto, A.

    1996-01-01

    Effective-field-theory methods are used to separate the free energy for a non-Abelian gauge theory at high temperature T into the contributions from the momentum scales T, gT, and g 2 T, where g is the coupling constant at the scale 2πT. The effects of the scale T enter through the coefficients in the effective Lagrangian for the three-dimensional effective theory obtained by dimensional reduction. These coefficients can be calculated as power series in g 2 . The contribution to the free energy from the scale gT can be calculated using perturbative methods in the effective theory. It can be expressed as an expansion in g starting at order g 3 . The contribution from the scale g 2 T must be calculated using nonperturbative methods, but nevertheless it can be expanded in powers of g beginning at order g 6 . We calculate the free energy explicitly to order g 5 . We also outline the calculations necessary to obtain the free energy to order g 6 . copyright 1996 The American Physical Society

  15. Turbulent Flow past High Temperature Surfaces

    Science.gov (United States)

    Mehmedagic, Igbal; Thangam, Siva; Carlucci, Pasquale; Buckley, Liam; Carlucci, Donald

    2014-11-01

    Flow over high-temperature surfaces subject to wall heating is analyzed with applications to projectile design. In this study, computations are performed using an anisotropic Reynolds-stress model to study flow past surfaces that are subject to radiative flux. The model utilizes a phenomenological treatment of the energy spectrum and diffusivities of momentum and heat to include the effects of wall heat transfer and radiative exchange. The radiative transport is modeled using Eddington approximation including the weighted effect of nongrayness of the fluid. The time-averaged equations of motion and energy are solved using the modeled form of transport equations for the turbulence kinetic energy and the scalar form of turbulence dissipation with an efficient finite-volume algorithm. The model is applied for available test cases to validate its predictive capabilities for capturing the effects of wall heat transfer. Computational results are compared with experimental data available in the literature. Applications involving the design of projectiles are summarized. Funded in part by U.S. Army, ARDEC.

  16. High-temperature archeointensity measurements from Mesopotamia

    Science.gov (United States)

    Gallet, Yves; Le Goff, Maxime

    2006-01-01

    We present new archeointensity results obtained from 127 potsherds and baked brick fragments dated from the last four millennia BC which were collected from different Syrian archeological excavations. High temperature magnetization measurements were carried out using a laboratory-built triaxial vibrating sample magnetometer (Triaxe), and ancient field intensity determinations were derived from the experimental procedure described by Le Goff and Gallet [Le Goff and Gallet. Earth Planet. Sci. Lett. 229 (2004) 31-43]. As some of the studied samples were previously analyzed using the classical Thellier and Thellier [Thellier and Thellier . Ann. Geophys. 15 (1959) 285-376] method revised by Coe [Coe. J. Geophys. Res. 72 (1967) 3247-3262], a comparison of the results is made from the two methods. The differences both at the fragment and site levels are mostly within ± 5%, which strengthens the validity of the experimental procedure developed for the Triaxe. The new data help to better constrain the geomagnetic field intensity variations in Mesopotamia during archeological times, with the probable occurrence of an archeomagnetic jerk around 2800-2600 BC.

  17. Fatigue crack growth control in pressure vessel using single peak overload and load hold at elevated temperatures

    International Nuclear Information System (INIS)

    Chen, Ling; Nakamura, Haruo; Kobayashi, Hideo

    1995-01-01

    Pressure vessels are periodically subjected to a proof test to assure structural integrity. During that period, it may be possible to control the fatigue crack growth by simultaneous heating globally or locally around a crack tip. From this viewpoint, retardation behavior of a fatigue crack due to a single peak overload at a high temperature (∼300degC) was examined in an A 533 B-1 steel. Parameters investigated were overload ratio, applied temperature, hold time at higher temperature, and unloading temperature of overload. The higher the applied temperature, the greater the effect of retardation especially when unloading of the overload is done at lower temperatures. Also, the hold time at maximum load promotes oxide-film-induced crack closure. To evaluate those effects, a simple model is proposed based on the Dugdale model. (author)

  18. Heat Transfer Modeling for Rigid High-Temperature Fibrous Insulation

    Science.gov (United States)

    Daryabeigi, Kamran; Cunnington, George R.; Knutson, Jeffrey R.

    2012-01-01

    Combined radiation and conduction heat transfer through a high-temperature, high-porosity, rigid multiple-fiber fibrous insulation was modeled using a thermal model previously used to model heat transfer in flexible single-fiber fibrous insulation. The rigid insulation studied was alumina enhanced thermal barrier (AETB) at densities between 130 and 260 kilograms per cubic meter. The model consists of using the diffusion approximation for radiation heat transfer, a semi-empirical solid conduction model, and a standard gas conduction model. The relevant parameters needed for the heat transfer model were estimated from steady-state thermal measurements in nitrogen gas at various temperatures and environmental pressures. The heat transfer modeling methodology was evaluated by comparison with standard thermal conductivity measurements, and steady-state thermal measurements in helium and carbon dioxide gases. The heat transfer model is applicable over the temperature range of 300 to 1360 K, pressure range of 0.133 to 101.3 x 10(exp 3) Pa, and over the insulation density range of 130 to 260 kilograms per cubic meter in various gaseous environments.

  19. Development of high temperature superconductors having high critical current density

    Energy Technology Data Exchange (ETDEWEB)

    Hong, Gye Wong; Kim, C. J.; Lee, H.G.; Kwon, S. C.; Lee, H. J.; Kim, K. B.; Park, J. Y.; Jung, C. H

    2000-08-01

    Fabrication of high T{sub c} superconductors and its applications for electric power device were carried out for developing superconductor application technologies. High quality YBCO superconductors was fabricated by melt texture growth, top-seeded melt growth process and multi-seeded melt growth process and the properties was compared. The critical current density of the melt processed YBCO superconductors was about few 10,000 A/cm{sup 2} and the levitation force was 50 N. The processing time needed for the growth of the 123 single grain was greatly reduced by applying multi-seeding without no significant degradation of the levitation force. The multi-seeded melt growth process was confirmed as a time-saving and cost-effective method for the fabrication of bulk superconductors with controlled crystallographic orientation.

  20. Room-Temperature Single-Photon Source for Secure Quantum Communication

    Data.gov (United States)

    National Aeronautics and Space Administration — We are asking for four years of support for PhD student Justin Winkler's work on a research project entitled "Room temperature single photon source for secure...

  1. High temperature impedance spectroscopy of barium stannate ...

    Indian Academy of Sciences (India)

    ... differential thermal analysis, thermogravimetric analysis and Fourier transform infrared techniques. Electrical properties were studied using a.c. impedance spectroscopy technique in the temperature range of 50–650 °C and frequency range of 10 Hz–13 MHz. The complex impedance plots at temperature ≥ 300 °C show ...

  2. High Temperature and Pressure Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank

    temperatures and pressures. Aqueous potassium hydroxide immobilized electrolyte in porous SrTiO3 was used in those cells. Electrolysis cells with metal foam based gas diffusion electrodes and the immobilized electrolyte were successfully demonstrated at temperatures up to 250 °C and 40 bar. Different electro...

  3. High temperature impedance spectroscopy of barium stannate

    Indian Academy of Sciences (India)

    ... differential thermal analysis, thermogravimetric analysis and Fourier transform infrared techniques. Electrical properties were studied using a.c. impedance spectroscopy technique in the temperature range of 50–650 °C and frequency range of 10 Hz–13 MHz. The complex impedance plots at temperature ≥ 300 °C show ...

  4. Electronic ceramics in high-temperature environments

    International Nuclear Information System (INIS)

    Searcy, A.W.; Meschi, D.J.

    1982-01-01

    Simple thermodynamic means are described for understanding and predicting the influence of temperature changes, in various environments, on electronic properties of ceramics. Thermal gradients, thermal cycling, and vacuum annealing are discussed, as well as the variations of ctivities and solubilities with temperature. 7 refs

  5. High performance internal reforming unit for high temperature fuel cells

    Science.gov (United States)

    Ma, Zhiwen [Sandy Hook, CT; Venkataraman, Ramakrishnan [New Milford, CT; Novacco, Lawrence J [Brookfield, CT

    2008-10-07

    A fuel reformer having an enclosure with first and second opposing surfaces, a sidewall connecting the first and second opposing surfaces and an inlet port and an outlet port in the sidewall. A plate assembly supporting a catalyst and baffles are also disposed in the enclosure. A main baffle extends into the enclosure from a point of the sidewall between the inlet and outlet ports. The main baffle cooperates with the enclosure and the plate assembly to establish a path for the flow of fuel gas through the reformer from the inlet port to the outlet port. At least a first directing baffle extends in the enclosure from one of the sidewall and the main baffle and cooperates with the plate assembly and the enclosure to alter the gas flow path. Desired graded catalyst loading pattern has been defined for optimized thermal management for the internal reforming high temperature fuel cells so as to achieve high cell performance.

  6. High temperature cement raw meal flowability

    DEFF Research Database (Denmark)

    Maarup, Claus; Hjuler, Klaus; Dam-Johansen, Kim

    2014-01-01

    The flowability of cement raw meal is investigated at temperatures up to 850°C in a specially designed monoaxial shear tester. Consolidation stresses of 0.94, 1.87 and 2.79kPa are applied. The results show that the flowability is reduced as temperature is increased above 550°C, indicated by incre......The flowability of cement raw meal is investigated at temperatures up to 850°C in a specially designed monoaxial shear tester. Consolidation stresses of 0.94, 1.87 and 2.79kPa are applied. The results show that the flowability is reduced as temperature is increased above 550°C, indicated...... by increasing unconfined yield strength and reduced flowability factors. Deviation and reproducibility are acceptable for all temperatures except for 850°C where belite formation and possibly calcination sinter the raw meal....

  7. Comparison of Single-Point and Continuous Sampling Methods for Estimating Residential Indoor Temperature and Humidity.

    Science.gov (United States)

    Johnston, James D; Magnusson, Brianna M; Eggett, Dennis; Collingwood, Scott C; Bernhardt, Scott A

    2015-01-01

    Residential temperature and humidity are associated with multiple health effects. Studies commonly use single-point measures to estimate indoor temperature and humidity exposures, but there is little evidence to support this sampling strategy. This study evaluated the relationship between single-point and continuous monitoring of air temperature, apparent temperature, relative humidity, and absolute humidity over four exposure intervals (5-min, 30-min, 24-hr, and 12-days) in 9 northern Utah homes, from March-June 2012. Three homes were sampled twice, for a total of 12 observation periods. Continuous data-logged sampling was conducted in homes for 2-3 wks, and simultaneous single-point measures (n = 114) were collected using handheld thermo-hygrometers. Time-centered single-point measures were moderately correlated with short-term (30-min) data logger mean air temperature (r = 0.76, β = 0.74), apparent temperature (r = 0.79, β = 0.79), relative humidity (r = 0.70, β = 0.63), and absolute humidity (r = 0.80, β = 0.80). Data logger 12-day means were also moderately correlated with single-point air temperature (r = 0.64, β = 0.43) and apparent temperature (r = 0.64, β = 0.44), but were weakly correlated with single-point relative humidity (r = 0.53, β = 0.35) and absolute humidity (r = 0.52, β = 0.39). Of the single-point RH measures, 59 (51.8%) deviated more than ±5%, 21 (18.4%) deviated more than ±10%, and 6 (5.3%) deviated more than ±15% from data logger 12-day means. Where continuous indoor monitoring is not feasible, single-point sampling strategies should include multiple measures collected at prescribed time points based on local conditions.

  8. High temperature experimental characterization of microscale thermoelectric effects

    Science.gov (United States)

    Favaloro, Tela

    temperature vacuum thermostats are designed and fabricated with optical imaging capability and interchangeable measurement stages for various electrical and thermoelectric characterizations. We demonstrate the simultaneous measurement of in-plane electrical conductivity and Seebeck coefficient of thin-film or bulk thermoelectric materials. Furthermore, we utilize high-speed circuitry to implement the transient Harman technique and directly determine the cross-plane figure of merit of thin film thermoelectric materials at high temperatures. Transient measurements on thin film devices are subject to complications from the growth substrate, non-ideal contacts and other detrimental thermal and electrical effects. A strategy is presented for optimizing device geometry to mitigate the impact of these parasitics. This design enabled us to determine the cross-plane thermoelectric material properties in a single high temperature measurement of a 25mum InGaAs thin film with embedded ErAs (0.2%) nanoparticles using the bipolar transient Harman technique in conjunction with thermoreflectance thermal imaging. This approach eliminates discrepancies and potential device degradation from the multiple measurements necessary to obtain individual material parameters. Finite element method simulations are used to analyze non-uniform current and temperature distributions over the device area and determine the three dimensional current path for accurate extraction of material properties from the thermal images. Results match with independent measurements of thermoelectric material properties for the same material composition, validating this approach. We apply high magnification thermoreflectance imaging to create temperature maps of vanadium dioxide nanobeams and examine electro-thermal energy conversion along the nanobeam length. The metal to insulator transition of strongly correlated materials is subject to strong lattice coupling which brings about the unique one-dimensional alignment of

  9. Ultra-High Temperature Distributed Wireless Sensors

    Energy Technology Data Exchange (ETDEWEB)

    May, Russell; Rumpf, Raymond; Coggin, John; Davis, Williams; Yang, Taeyoung; O' Donnell, Alan; Bresnahan, Peter

    2013-03-31

    Research was conducted towards the development of a passive wireless sensor for measurement of temperature in coal gasifiers and coal-fired boiler plants. Approaches investigated included metamaterial sensors based on guided mode resonance filters, and temperature-sensitive antennas that modulate the frequency of incident radio waves as they are re-radiated by the antenna. In the guided mode resonant filter metamaterial approach, temperature is encoded as changes in the sharpness of the filter response, which changes with temperature because the dielectric loss of the guided mode resonance filter is temperature-dependent. In the mechanically modulated antenna approach, the resonant frequency of a vibrating cantilever beam attached to the antenna changes with temperature. The vibration of the beam perturbs the electrical impedance of the antenna, so that incident radio waves are phase modulated at a frequency equal to the resonant frequency of the vibrating beam. Since the beam resonant frequency depends on temperature, a Doppler radar can be used to remotely measure the temperature of the antenna. Laboratory testing of the guided mode resonance filter failed to produce the spectral response predicted by simulations. It was concluded that the spectral response was dominated by spectral reflections of radio waves incident on the filter. Laboratory testing of the mechanically modulated antenna demonstrated that the device frequency shifted incident radio waves, and that the frequency of the re-radiated waves varied linearly with temperature. Radio wave propagation tests in the convection pass of a small research boiler plant identified a spectral window between 10 and 13 GHz for low loss propagation of radio waves in the interior of the boiler.

  10. Fluorescence spectroscopy of single molecules at room temperature and its applications

    Energy Technology Data Exchange (ETDEWEB)

    Ha, Taekjip [Univ. of California, Berkeley, CA (United States)

    1996-12-01

    We performed fluorescence spectroscopy of single and pairs of dye molecules on a surface at room temperature. Near field scanning optical microscope (NSOM) and far field scanning optical microscope with multi-color excitation/detection capability were built. The instrument is capable of optical imaging with 100nm resolution and has the sensitivity necessary for single molecule detection. A variety of dynamic events which cannot be observed from an ensemble of molecules is revealed when the molecules are probed one at a time. They include (1) spectral jumps correlated with dark states, (2) individually resolved quantum jumps to and from the meta-stable triplet state, (3) rotational jumps due to desorption/readsorption events of single molecules on the surface. For these studies, a computer controlled optical system which automatically and rapidly locates and performs spectroscopic measurements on single molecules was developed. We also studied the interaction between closely spaced pairs of molecules. In particular, fluorescence resonance energy transfer between a single resonant pair of donor and acceptor molecules was measured. Photodestruction dynamics of the donor or acceptor were used to determine the presence and efficiency of energy transfer Dual molecule spectroscopy was extended to a non-resonant pair of molecules to obtain high resolution differential distance information. By combining NSOM and dual color scheme, we studied the co-localization of parasite proteins and host proteins on a human red blood cell membrane infected with malaria. These dual-molecule techniques can be used to measure distances, relative orientations, and changes in distances/orientations of biological macromolecules with very good spatial, angular and temporal resolutions, hence opening new capabilities in the study of such systems.

  11. Application of an improved operational strategy for a high temperature-proton exchange membrane fuel cell-based micro-combined heat and power system for Danish single-family households

    DEFF Research Database (Denmark)

    Arsalis, Alexandros; Nielsen, Mads Pagh; Kær, Søren Knudsen

    2013-01-01

    characteristics. Based on these findings, an improved operational strategy is formulated and applied in an attempt to minimize the shortcomings of conventional strategies. System parameters, such as electrical and thermal efficiencies, heat dumping, and import/export of electricity, are analyzed. The applied load......A proposed residential energy system based on the PBI (Polybenzimidazole) fuel cell technology is analyzed in terms of operational performance. Conventional operational strategies, such as heat-led and electricity-led, are applied to the simulated system to investigate their performance...... profile is based on average data for a single-family household in Denmark and includes consumption data for electricity and heat demands. The study analyzes the potential of the proposed system on market penetration in the area of residential heat-and-power generation and whether this deployment can...

  12. FEM Modeling of the Relationship between the High-Temperature Hardness and High-Temperature, Quasi-Static Compression Experiment.

    Science.gov (United States)

    Zhang, Tao; Jiang, Feng; Yan, Lan; Xu, Xipeng

    2017-12-26

    The high-temperature hardness test has a wide range of applications, but lacks test standards. The purpose of this study is to develop a finite element method (FEM) model of the relationship between the high-temperature hardness and high-temperature, quasi-static compression experiment, which is a mature test technology with test standards. A high-temperature, quasi-static compression test and a high-temperature hardness test were carried out. The relationship between the high-temperature, quasi-static compression test results and the high-temperature hardness test results was built by the development of a high-temperature indentation finite element (FE) simulation. The simulated and experimental results of high-temperature hardness have been compared, verifying the accuracy of the high-temperature indentation FE simulation.The simulated results show that the high temperature hardness basically does not change with the change of load when the pile-up of material during indentation is ignored. The simulated and experimental results show that the decrease in hardness and thermal softening are consistent. The strain and stress of indentation were analyzed from the simulated contour. It was found that the strain increases with the increase of the test temperature, and the stress decreases with the increase of the test temperature.

  13. FEM Modeling of the Relationship between the High-Temperature Hardness and High-Temperature, Quasi-Static Compression Experiment

    Directory of Open Access Journals (Sweden)

    Tao Zhang

    2017-12-01

    Full Text Available The high-temperature hardness test has a wide range of applications, but lacks test standards. The purpose of this study is to develop a finite element method (FEM model of the relationship between the high-temperature hardness and high-temperature, quasi-static compression experiment, which is a mature test technology with test standards. A high-temperature, quasi-static compression test and a high-temperature hardness test were carried out. The relationship between the high-temperature, quasi-static compression test results and the high-temperature hardness test results was built by the development of a high-temperature indentation finite element (FE simulation. The simulated and experimental results of high-temperature hardness have been compared, verifying the accuracy of the high-temperature indentation FE simulation.The simulated results show that the high temperature hardness basically does not change with the change of load when the pile-up of material during indentation is ignored. The simulated and experimental results show that the decrease in hardness and thermal softening are consistent. The strain and stress of indentation were analyzed from the simulated contour. It was found that the strain increases with the increase of the test temperature, and the stress decreases with the increase of the test temperature.

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-08-30

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

  15. Single-component reflecting objective for low-temperature spectroscopy in the entire visible region

    NARCIS (Netherlands)

    Fujiyoshi, Satoru; Fujiwara, Masanori; Kim, Changman; Matsushita, Michio; Oijen, Antoine M. van; Schmidt, Jan

    2007-01-01

    A single-component reflecting objective was constructed for low-temperature spectroscopy with optimal imaging and transmission properties at all visible wavelengths. The performance of the objective immersed in superfluid helium at a temperature of 1.5 K was tested by comparing dark-field images of

  16. CAST-IRONS AT HIGH TEMPERATURES

    Directory of Open Access Journals (Sweden)

    A. N. Krutilin

    2008-01-01

    Full Text Available The results of investigations of physical-mechanical characteristics of cast iron slugs, received by semicontinuos way of casting, at temperatures from 850 up to 1100^ С are given. 

  17. Packaging Technology for SiC High Temperature Electronics

    Science.gov (United States)

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

    2017-01-01

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

  18. Fusion reactors-high temperature electrolysis (HTE)

    International Nuclear Information System (INIS)

    Fillo, J.A.

    1978-01-01

    Results of a study to identify and develop a reference design for synfuel production based on fusion reactors are given. The most promising option for hydrogen production was high-temperature electrolysis (HTE). The main findings of this study are: 1. HTE has the highest potential efficiency for production of synfuels from fusion; a fusion to hydrogen energy efficiency of about 70% appears possible with 1800 0 C HTE units and 60% power cycle efficiency; an efficiency of about 50% possible with 1400 0 C HTE units and 40% power cycle efficiency. 2. Relative to thermochemical or direct decomposition methods HTE technology is in a more advanced state of development, 3. Thermochemical or direct decomposition methods must have lower unit process or capital costs if they are to be more attractive than HTE. 4. While design efforts are required, HTE units offer the potential to be quickly run in reverse as fuel cells to produce electricity for restart of Tokamaks and/or provide spinning reserve for a grid system. 5. Because of the short timescale of the study, no detailed economic evaluation could be carried out.A comparison of costs could be made by employing certain assumptions. For example, if the fusion reactor-electrolyzer capital installation is $400/(KW(T) [$1000/KW(E) equivalent], the H 2 energy production cost for a high efficiency (about 70 %) fusion-HTE system is on the same order of magnitude as a coal based SNG plant based on 1976 dollars. 6. The present reference design indicates that a 2000 MW(th) fusion reactor could produce as much at 364 x 10 6 scf/day of hydrogen which is equivalent in heating value to 20,000 barrels/day of gasoline. This would fuel about 500,000 autos based on average driving patterns. 7. A factor of three reduction in coal feed (tons/day) could be achieved for syngas production if hydrogen from a fusion-HTE system were used to gasify coal, as compared to a conventional syngas plant using coal-derived hydrogen

  19. Voltage stabilizers for high temperature furnace

    International Nuclear Information System (INIS)

    Huet, J.

    1966-10-01

    The stabilization of furnace temperatures in the range 1500-2500 C has been achieved by controlling the effective (rms) value of the supply voltage of the heating element. Temperature variations are less than, or equal to, one degree C in the whole working range of the furnace. Two types of set-ups have been developed: one is static, the other takes use of a servo-motor. (author) [fr

  20. Changes of microstructures and high temperature properties during high temperature service of Niobium added ferritic stainless steels

    International Nuclear Information System (INIS)

    Fujita, Nobuhiro; Ohmura, Keiichi; Yamamoto, Akio

    2003-01-01

    To improve the fuel economy and clean the exhaust gas of automobiles, the temperature of exhaust gas is getting higher and higher. Niobium added ferritic stainless steels are often being used in automotive exhaust systems, because of their excellent heat resistant properties, especially thermal fatigue resistance, which is very important for materials of exhaust manifold. However, coarse precipitates containing niobium, which cause degradation in high temperature strength and thermal fatigue resistance, are unavoidable during high temperature service. In this study, changes of microstructures and high temperature properties in high temperature aging were investigated using several Nb added ferritic stainless steels. It has been found that the microstructure stability of Nb-Ti-Mo alloyed steels in high temperature aging is superior to that of Nb added steels. The microstructure stability leads to less degradation in high temperature strength during high temperature aging and to longer thermal fatigue lives of Nb-Ti-Mo alloyed steels than in Nb added steels

  1. Electromagnetic properties of terbium gallium garnet at millikelvin temperatures and single photon energy

    OpenAIRE

    Kostylev, Nikita; Goryachev, Maxim; Bushev, Pavel; Tobar, Michael E.

    2017-01-01

    Electromagnetic properties of single crystal terbium gallium garnet (TGG) are characterised from room down to millikelvin temperatures using the whispering gallery mode method. Microwave spectroscopy is performed at low powers equivalent to a few photons in energy and conducted as functions of the magnetic field and temperature. A phase transition is detected close to the temperature of 3.5 K. This is observed for multiple whispering gallery modes causing an abrupt negative frequency shift an...

  2. Simulation study based on the single-point temperature monitoring system of LabVIEW

    Science.gov (United States)

    Wu, Yongling; Yang, Na; Liu, Shuping; Pan, Xiaohui; Wang, Wenjiang

    2014-12-01

    This paper takes LabVIEW2012 as a development platform, creating a J-type thermocouple sensor and the NI USB-6229 data acquisition card and other hardware emulation circuitry which combined with the PC designed a single-point temperature monitoring system. Through simulation experiments, the system has a collection interval, the sampling rate per channel sampling on the temperature limit set by the user function and it also has the function of real-time display the current temperature, the temperature limit alarm, maximum temperature, minimum temperature display and a temperature history data query. This system can be used for temperature monitoring of life, research, industrial control, environmental monitoring, biomedical, tobacco processing, greenhouse cultivation, livestock breeding and other fields, which has important significance and practical value.

  3. High temperature nuclear heat for isothermal reformer

    International Nuclear Information System (INIS)

    Epstein, M.

    2000-01-01

    High temperature nuclear heat can be used to operate a reformer with various feedstock materials. The product synthesis gas can be used not only as a source for hydrogen and as a feedstock for many essential chemical industries, such as ammonia and other products, but also for methanol and synthetic fuels. It can also be burnt directly in a combustion chamber of a gas turbine in an efficient combined cycle and generate electricity. In addition, it can be used as fuel for fuel cells. The reforming reaction is endothermic and the contribution of the nuclear energy to the calorific value of the final product (synthesis gas) is about 25%, compared to the calorific value of the feedstock reactants. If the feedstock is from fossil origin, the nuclear energy contributes to a substantial reduction in CO 2 emission to the atmosphere. The catalytic steam reforming of natural gas is the most common process. However, other feedstock materials, such as biogas, landfill gas and CO 2 -contaminated natural gas, can be reformed as well, either directly or with the addition of steam. The industrial steam reformers are generally fixed bed reactors, and their performance is strongly affected by the heat transfer from the furnace to the catalyst tubes. In top-fired as well as side-fired industrial configurations of steam reformers, the radiation is the main mechanism of heat transfer and convection heat transfer is negligible. The flames and the furnace gas constitute the main sources of the heat. In the nuclear reformers developed primarily in Germany, in connection with the EVA-ADAM project (closed cycle), the nuclear heat is transferred from the nuclear reactor coolant gas by convection, using a heating jacket around the reformer tubes. In this presentation it is proposed that the helium in a secondary loop, used to cool the nuclear reactor, will be employed to evaporate intermediate medium, such as sodium, zinc and aluminum chloride. Then, the vapors of the medium material transfer

  4. [Genesis study of omphacite at high pressure and high temperature].

    Science.gov (United States)

    Xiao, Ben-Fu; Yi, Li; Wang, Duo-Jun; Xie, Chao; Tang, Xue-Wu; Liu, Lei; Cui, Yue-Ju

    2013-11-01

    The melting and recrystallizing experiments of alkali basalt powder and mixture of pure oxides mixed as stoichiometry were performed at 3 GPa and 1 200 degrees C. Electronic microprobe analysis and Raman spectra showed that the recrystallized products were omphacites, the FWHM (full width at half maximum) of the Raman peak was narrow and its shape was sharp, which is attributed to the stable Si-O tetrahedral structure and the high degree of order in omphacite. Based on the results of previous studies, the influencing factors of omphacite genesis and its primary magma were discussed. The results showed that the formation of omphacite could be affected by many factors, such as the composition of parent rocks, the concentration of fluid in the system and the conditions of pressure and temperature. This result could support some experimental evidences on the genesis studies of omphacite and eclogite.

  5. TOPICAL REVIEW: High-temperature microwave processing of materials

    Science.gov (United States)

    Bykov, Yu V.; Rybakov, K. I.; Semenov, V. E.

    2001-07-01

    This article reviews the physical aspects of a cross-disciplinary science and technology field: the microwave processing of materials. High-temperature microwave processing has a clear industrial perspective in such areas as the production of advanced ceramics, the deposition of thermal barrier coatings, the remediation of hazardous wastes etc. This review starts with the relevant fundamental notions regarding the absorption of electromagnetic waves, heat transfer and the electrodynamics of single- and multimode microwave cavities. Useful formulae, estimates, and interrelations between process variables are presented. This is followed by a review of process examples illustrating the specific features of microwave processing: reduction in energy consumption and process duration, rapid and controllable heating, peculiar temperature distribution, and selectivity of energy deposition. Much attention is given to the advantages of higher-frequency millimetre-wave processing, which include the enhanced absorption in many materials of industrial interest, improved uniformity of electromagnetic energy and temperature, and the possibility of surface treatment. The phenomenon of microwave process rate enhancement is addressed in connection with the problem of the non-thermal microwave effect on mass transport in solids. Both experimental and theoretical approaches to the identification of the mechanism responsible for this effect are illustrated. Finally, the physical and technical factors influencing microwave technology scaleup and transfer to industry are discussed.

  6. Single Assignment C (SAC): High Productivity meets High Performance

    NARCIS (Netherlands)

    Grelck, C.; Zsók, V.; Horváth, Z.; Plasmeijer, R.

    2012-01-01

    We present the ins and outs of the purely functional, data parallel programming language SaC (Single Assignment C). SaC defines state- and side-effect-free semantics on top of a syntax resembling that of imperative languages like C/C++/C# or Java: functional programming with curly brackets. In

  7. The impact of high temperatures on foraging behaviour and body ...

    African Journals Online (AJOL)

    High temperatures can pose significant thermoregulation challenges for endotherms, and determining how individual species respond to high temperatures will be important for predicting the impact of global warming on wild populations. Animals can adjust their behaviour or physiology to cope with higher temperatures, ...

  8. Study on the temperature field of large-sized sapphire single crystal furnace

    Science.gov (United States)

    Zhai, J. P.; Jiang, J. W.; Liu, K. G.; Peng, X. B.; Jian, D. L.; Li, I. L.

    2018-01-01

    In this paper, the temperature field of large-sized (120kg, 200kg and 300kg grade) sapphire single crystal furnace was simulated. By keeping the crucible diameter ratio and the insulation system unchanged, the power consumption, axial and radial temperature gradient, solid-liquid surface shape, stress distribution and melt flow were studied. The simulation results showed that with the increase of the single crystal furnace size, the power consumption increased, the temperature field insulation effect became worse, the growth stress value increased and the stress concentration phenomenon occurred. To solve these problems, the middle and bottom insulation system should be enhanced during designing the large-sized sapphire single crystal furnace. The appropriate radial and axial temperature gradient was favorable to reduce the crystal stress and prevent the occurrence of cracking. Expanding the interface between the seed and crystal was propitious to avoid the stress accumulation phenomenon.

  9. High temperature oxidation behavior of TiAl-based intermetallics

    International Nuclear Information System (INIS)

    Stroosnijder, M.F.; Sunderkoetter, J.D.; Haanappel, V.A.C.

    1996-01-01

    TiAl-based intermetallic compounds have attracted considerable interest as structural materials for high-temperature applications due to their low density and substantial mechanical strength at high temperatures. However, one major drawback hindering industrial application arises from the insufficient oxidation resistance at temperatures beyond 700 C. In the present contribution some general aspects of high temperature oxidation of TiAl-based intermetallics will be presented. This will be followed by a discussion of the influence of alloying elements, in particular niobium, and of the effect of nitrogen in the oxidizing environment on the high temperature oxidation behavior of such materials

  10. 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

  11. A comparative study of single-temperature and two-temperature ...

    Indian Academy of Sciences (India)

    INDU KALPA DIHINGIA

    2018-02-09

    Feb 9, 2018 ... ions collide due to the random thermal motion. Dur- ing collision, energy is being exchanged between the ... ing a pseudo Newtonian potential. The form of the potential in cylindrical coordinate is ... flow, ions and electrons remain coupled and therefore, we have single entropy generation equation which is.

  12. On high temperature internal friction in metallic glasses

    International Nuclear Information System (INIS)

    Zolotukhin, I.V.; Kalinin, Yu.E.; Roshchupkin, A.M.

    1992-01-01

    High temperature background of internal friction in amorphous lanthanum-aluminium alloys was investigated. More rapid growth of internal friction was observed at temperature ∼ 453 K reaching maximal value at 495 K. Crystallization process was accompanied by decrease of internal friction. Increase of mechanical vibration frequency to 1000 Hz leads to rise of internal friction background in the range of room temperatures and to decrease at temperatures above 370 K. Bend was observed on temperature dependence of internal friction at 440 K

  13. High Performance Relaxor-Based Ferroelectric Single Crystals for Ultrasonic Transducer Applications

    Directory of Open Access Journals (Sweden)

    Yan Chen

    2014-07-01

    Full Text Available Relaxor-based ferroelectric single crystals Pb(Mg1/3Nb2/3O3-PbTiO3 (PMN-PT have drawn much attention in the ferroelectric field because of their excellent piezoelectric properties and high electromechanical coupling coefficients (d33~2000 pC/N, kt~60% near the morphotropic phase boundary (MPB. Ternary Pb(In1/2Nb1/2O3-Pb(Mg1/3Nb2/3O3-PbTiO3 (PIN-PMN-PT single crystals also possess outstanding performance comparable with PMN-PT single crystals, but have higher phase transition temperatures (rhombohedral to tetragonal Trt, and tetragonal to cubic Tc and larger coercive field Ec. Therefore, these relaxor-based single crystals have been extensively employed for ultrasonic transducer applications. In this paper, an overview of our work and perspectives on using PMN-PT and PIN-PMN-PT single crystals for ultrasonic transducer applications is presented. Various types of single-element ultrasonic transducers, including endoscopic transducers, intravascular transducers, high-frequency and high-temperature transducers fabricated using the PMN-PT and PIN-PMN-PT crystals and their 2-2 and 1-3 composites are reported. Besides, the fabrication and characterization of the array transducers, such as phased array, cylindrical shaped linear array, high-temperature linear array, radial endoscopic array, and annular array, are also addressed.

  14. A temperature-compensated high spatial resolution distributed strain sensor

    International Nuclear Information System (INIS)

    Belal, Mohammad; Cho, Yuh Tat; Ibsen, Morten; Newson, Trevor P

    2010-01-01

    We propose and demonstrate a scheme which utilizes the temperature dependence of spontaneous Raman scattering to provide temperature compensation for a high spatial resolution Brillouin frequency-based strain sensor

  15. High Temperature Protonic Conductors by Melt Growth

    National Research Council Canada - National Science Library

    Fernandez, Julian M

    2003-01-01

    This report results from a contract tasking Universidad de Sevilla as follows: The objective of the proposed research is to produce single crystal and multiphase ceramic materials of BaCe1-xNdxO3-a and Ba3(CaNb2...

  16. High temperature fatigue behaviour of intermetallics

    Indian Academy of Sciences (India)

    M. Senthilkumar (Newgen Imaging) 1461 1996 Oct 15 13:05:22

    brittle to ductile transition temperature, mean stress and environment on fatigue behaviour of same γ-TiAl alloys are discussed. Keywords. Nickel aluminides; titanium aluminides; low cycle fatigue; micro- alloying. 1. Introduction. Ordered intermetallic alloys have undergone extensive development over the past two decades.

  17. High Temperature Resistant Exhaust Valve Spindle

    DEFF Research Database (Denmark)

    Bihlet, Uffe Ditlev

    Transport by ship remains the most economical and environmentally friendly mode of transport with a very low weight specific CO2 footprint. Further increase of the fuel efficiency of large ships will results in a higher internal engine temperature. To allow this without compromising the reliabili...

  18. Thermal insulation of high temperature reactors

    International Nuclear Information System (INIS)

    Cornille, Y.

    1975-01-01

    Operating conditions of HTR thermal insulation are given and heat insulators currently developed are described (fibers kept in position by metallic structures). For future applications and higher temperatures, research is directed towards solutions using ceramics or associating fibers and ceramics [fr

  19. High temperatures influence sexual development differentially in ...

    Indian Academy of Sciences (India)

    Samadhan Krushna Phuge

    2017-06-20

    Jun 20, 2017 ... stage 42 (during feeding stages F; figure 1). 2.3 Post-experimental rearing and evaluation of effect of temperature. On reaching stage 42 (forelimb emergence), tadpoles from all the groups were transferred in separate plastic tubs with some water to facilitate metamorphosis. The larval life duration of each ...

  20. High temperature oxidation of slurry coated interconnect alloys

    DEFF Research Database (Denmark)

    Persson, Åsa Helen

    performed on extra Sandvik alloys. The slurry coatings consisted of perovskite, spinel, corundum, and rutile oxides and they were both applied as single layer coatings and as dual layer coatings. Cross-sections of the oxidized samples were analyzed with scanning electron microscopy, SEM, and energy......In this project, high temperature oxidation experiments of slurry coated ferritic alloys in atmospheres similar to the atmosphere found at the cathode in an SOFC were conducted. From the observations possible interaction mechanisms between the slurry coatings and the growing oxide scale...... on the alloy surface were formulated. These mechanisms are a step towards deeper knowledge of how to design a coating/alloy combination with satisfactory performance in an SOFC-stack. A satisfactory performance entails a low growth rate of the forming oxide scale on the alloy surface and a low chromium content...

  1. Improving the high performance concrete (HPC behaviour in high temperatures

    Directory of Open Access Journals (Sweden)

    Cattelan Antocheves De Lima, R.

    2003-12-01

    Full Text Available High performance concrete (HPC is an interesting material that has been long attracting the interest from the scientific and technical community, due to the clear advantages obtained in terms of mechanical strength and durability. Given these better characteristics, HFC, in its various forms, has been gradually replacing normal strength concrete, especially in structures exposed to severe environments. However, the veiy dense microstructure and low permeability typical of HPC can result in explosive spalling under certain thermal and mechanical conditions, such as when concrete is subject to rapid temperature rises, during a f¡re. This behaviour is caused by the build-up of internal water pressure, in the pore structure, during heating, and by stresses originating from thermal deformation gradients. Although there are still a limited number of experimental programs in this area, some researchers have reported that the addition of polypropylene fibers to HPC is a suitable way to avoid explosive spalling under f re conditions. This change in behavior is derived from the fact that polypropylene fibers melt in high temperatures and leave a pathway for heated gas to escape the concrete matrix, therefore allowing the outward migration of water vapor and resulting in the reduction of interned pore pressure. The present research investigates the behavior of high performance concrete on high temperatures, especially when polypropylene fibers are added to the mix.

    El hormigón de alta resistencia (HAR es un material de gran interés para la comunidad científica y técnica, debido a las claras ventajas obtenidas en término de resistencia mecánica y durabilidad. A causa de estas características, el HAR, en sus diversas formas, en algunas aplicaciones está reemplazando gradualmente al hormigón de resistencia normal, especialmente en estructuras expuestas a ambientes severos. Sin embargo, la microestructura muy densa y la baja permeabilidad t

  2. High temperature superconductor cable concepts for fusion magnets

    CERN Document Server

    AUTHOR|(CDS)2078397

    2013-01-01

    Three concepts of high temperature superconductor cables carrying kA currents (RACC, CORC and TSTC) are investigated, optimized and evaluated in the scope of their applicability as conductor in fusion magnets. The magnetic field and temperature dependence of the cables is measured; the thermal expansion and conductivity of structure, insulation and filling materials are investigated. High temperature superconductor winding packs for fusion magnets are calculated and compared with corresponding low temperature superconductor cases.

  3. Low-threshold room-temperature AlGaAs/GaAs nanowire/single-quantum-well heterostructure laser

    Science.gov (United States)

    Yan, Xin; Wei, Wei; Tang, Fengling; Wang, Xi; Li, Luying; Zhang, Xia; Ren, Xiaomin

    2017-02-01

    Near-infrared nanowire lasers are promising as ultrasmall, low-consumption light emitters in on-chip optical communications and computing systems. Here, we report on a room-temperature near-infrared nanolaser based on an AlGaAs/GaAs nanowire/single-quantum-well heterostructure grown by Au-catalyzed metal organic chemical vapor deposition. When subjects to pulsed optical excitation, the nanowire exhibits lasing, with a low threshold of 600 W/cm2, a narrow linewidth of 0.39 nm, and a high Q factor of 2000 at low temperature. Lasing is observed up to 300 K, with an ultrasmall temperature dependent wavelength shift of 0.045 nm/K. This work paves the way towards ultrasmall, low-consumption, and high-temperature-stability near-infrared nanolasers.

  4. High temperature structural, polymeric foams from high internal emulsion polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Hoisington, M.A.; Duke, J.R.; Apen, P.G.

    1996-02-01

    In 1982, a high internal phase emulsion (HIPE) polymerization process to manufacture microcellular, polymeric foam systems was patented by Unilever. This patent discloses a polymerization process that occurs in a water-in-oil emulsion in which the water represents at least 76% of the emulsion by volume. The oil phase consists of vinyl monomers such as styrene and acrylates that are crosslinked by divinyl monomers during polymerization. After polymerization and drying to remove the water phase, the result is a crosslinked polymer foam with an open cell microstructure that is homogeneous throughout in terms of morphology, density, and mechanical properties. Since 1982, numerous patents have examined various HIPE polymerized foam processing techniques and applications that include absorbents for body fluids, cleaning materials, and ion exchange systems. All the published HIPE polymerized foams have concentrated on materials for low temperature applications. Copolymerization of styrene with maleic anhydride and N-substituted maleimides to produce heat resistant thermoplastics has been studied extensively. These investigations have shown that styrene will free radically copolymerize with N-substituted maleimides to create an alternating thermoplastic copolymer with a Tg of approximately 200{degrees}C. However, there are many difficulties in attempting the maleimide styrene copolymerization in a HIPE such as lower polymerization temperatures, maleimide solubility difficulties in both styrene and water, and difficulty obtaining a stable HIPE with a styrene/maleimide oil phase. This work describes the preparation of copolymer foams from N-ethylmaleimide and Bis(3-ethyl-5-methyl-4-maleimide-phenyl)methane with styrene based monomers and crosslinking agents.

  5. Behaviors of SiC fibers at high temperature

    International Nuclear Information System (INIS)

    Colin, C.; Falanga, V.; Gelebart, L.

    2010-01-01

    On the one hand, considering the improvements of mechanical and thermal behaviours of the last generation of SiC fibers (Hi-Nicalon S, Tyranno SA3); on the other hand, regarding physical and chemical properties and stability under irradiation, SiC/SiC composites are potential candidates for nuclear applications in advanced fission and fusion reactors. CEA must characterize and optimize these composites before their uses in reactors. In order to study this material, CEA is developing a multi-scale approach by modelling from fibers to bulk composite specimen: fibres behaviours must be well known in first. Thus, CEA developed a specific tensile test device on single fibers at high temperature, named MecaSiC. Using this device, we have already characterized the thermoelastic and thermoelectric behaviours of SiC fibers. Additional results about the plastic properties at high temperatures were also obtained. Indeed, we performed tensile tests between 1200 degrees C up to 1700 degrees C to characterize this plastic behaviour. Some thermal annealing, up to 3 hours at 1700 degrees C, had been also performed. Furthermore, we compare the mechanical behaviours with the thermal evolution of the electric resistivity of these SiC fibers. Soon, MecaSiC will be coupled to a new charged particle accelerator. Thus, in this configuration, we will be able to study in-situ irradiation effects on fibre behaviours, as swelling or creep for example

  6. Energetics of Intermediate Temperature Solid Oxide Fuel Cell Electrolytes: Singly and Doubly doped Ceria Systems

    Science.gov (United States)

    Buyukkilic, Salih

    Solid oxide fuel cells (SOFCs) have potential to convert chemical energy directly to electrical energy with high efficiency, with only water vapor as a by-product. However, the requirement of extremely high operating temperatures (~1000 °C) limits the use of SOFCs to only in large scale stationary applications. In order to make SOFCs a viable energy solution, enormous effort has been focused on lowering the operating temperatures below 700 °C. A low temperature operation would reduce manufacturing costs by slowing component degradation, lessening thermal mismatch problems, and sharply reducing costs of operation. In order to optimize SOFC applications, it is critical to understand the thermodynamic stabilities of electrolytes since they directly influence device stability, sustainability and performance. Rare-earth doped ceria electrolytes have emerged as promising materials for SOFC applications due to their high ionic conductivity at the intermediate temperatures (500--700 °C). However there is a fundamental lack of understanding regarding their structure, thermodynamic stability and properties. Therefore, the enthalpies of formation from constituent oxides and ionic conductivities were determined to investigate a relationship between the stability, composition, structural defects and ionic conductivity in rare earth doped ceria systems. For singly doped ceria electrolytes, we investigated the solid solution phase of bulk Ce1-xLnxO2-0.5x where Ln = Sm and Nd (0 ≤ x ≤ 0.30) and analyzed their enthalpies of formation, mixing and association, and bulk ionic conductivities while considering cation size mismatch and defect associations. It was shown that for ambient temperatures in the dilute dopant region, the positive heat of formation reaches a maximum as the system becomes increasingly less stable due to size mismatch. In concentrated region, stabilization to a certain solubility limit was observed probably due to the defect association of trivalent cations

  7. Ground surface temperature history at a single site in southern Portugal reconstructed from borehole temperatures

    Czech Academy of Sciences Publication Activity Database

    Correia, A.; Šafanda, Jan

    2001-01-01

    Roč. 29, 3/4 (2001), s. 155-165 ISSN 0921-8181 Grant - others:NATO(XX) CP(CZ)4/D/96/PO; UNESCO(XX) IGCP No.428 Institutional research plan: CEZ:AV0Z3012916 Keywords : recent climate * global warming * borehole temperatures * Portugal Subject RIV: DC - Siesmology, Volcanology, Earth Structure Impact factor: 1.381, year: 2001

  8. A summary of high-temperature electronics research and development

    International Nuclear Information System (INIS)

    Thome, F.V.; King, D.B.

    1991-01-01

    Current and future needs in automative, aircraft, space, military, and well logging industries require operation of electronics at higher temperatures than today's accepted limit of 395 K. Without the availability of high-temperature electronics, many systems must operate under derated conditions or must accept severe mass penalties required by coolant systems to maintain electronic temperatures below critical levels. This paper presents ongoing research and development in the electronics community to bring high-temperature electronics to commercial realization. Much of this work was recently reviewed at the First International High-Temperature Electronics Conference held 16--20 June 1991 in Albuquerque, New Mexico. 4 refs., 1 tab

  9. 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

  10. High temperature sodium-concrete interactions

    International Nuclear Information System (INIS)

    Chasanov, M.G.; Staahl, G.E. Sr.

    1977-01-01

    Concrete specimens were immersed in sodium at 500 0 C, and the sodium-concrete interactions were studied. At this temperature the important reaction between CO 2 , produced by the limestone aggregate concrete, and sodium is 4Na+CO 2 → 2Na 2 O+C. This reaction is of interest for reactor safety analysis as it could act as a means of reducing gas pressures arising from CO 2 release by the concrete, in sodium cooled reactors. (B.D.)

  11. Thermodynamic behaviour of tellurium at high temperatures

    International Nuclear Information System (INIS)

    Garisto, F.

    1992-09-01

    Thermodynamic calculations are used to determine the chemical speciation of tellurium in the primary heat transport system under postulated reactor accident conditions. The speciation of tellurium is determined for various values of the temperature, oxygen partial pressure, tellurium concentration and Cs/Te ratio. The effects of the Zircaloy cladding and/or cesium on tellurium speciation and volatility are of particular interest in this report. (Author) (37 refs., 14 figs., 4 tabs.)

  12. High Temperature QCD and Dimensional Reduction

    Science.gov (United States)

    Petersson, Bengt

    2001-04-01

    In this talk I will first give a short discussion of some lattice results for QCD at finite temperature. I will then describe in some detail the technique of dimensional reduction, which in principle is a powerful technique to obtain results on the long distance properties of the quark-gluon plasma. Finally I will describe some new results, which test the technique in a simpler model, namely three dimensional gauge theory.

  13. High Energy Single Frequency Resonant Amplifier, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — This SBIR phase I project proposes a single frequency high energy resonant amplifier for remote sensing. Current state-of-art technologies can not provide all...

  14. Double Bag VARTM for High Temperature Composites, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — Cost and size are limiting factors in efforts to produce high strength, high stiffness, and high temperature composite parts. To address these issues, new processes...

  15. Double Bag VARTM for High Temperature Composites Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Cost and size are limiting factors in efforts to produce high strength, high stiffness, and high temperature composite parts. To address these issues, new processes...

  16. Effects of temperature on SCC propagation in high temperature water injected with hydrogen peroxide

    International Nuclear Information System (INIS)

    Nakano, Junichi; Sato, Tomonori; Kato, Chiaki; Yoshiyuki, Kaji; Yamamoto, Masahiro; Tsukada, Takashi

    2012-09-01

    film were performed on the fracture surface. In addition, to estimate the environmental situation in crack by prediction of oxide formation, a thermal equilibrium calculation was performed using a computer code for simulating aqueous-based chemical systems. Tensile tests were also carried out at 453 and 561 K in air to evaluate an effect of temperature on mechanical properties. Conclusions obtained in this study are summarized as follows; (1) Specimen exposed to 100 ppb H 2 O 2 at 453 K and 8 ppm O 2 at 561 K showed a steady SCC propagation behaviour. In 100 ppb H 2 O 2 at 561 K, however, an intergranular type SCC (IGSCC) was observed only small portion of area near the side groove of specimen. Effects of H 2 O 2 on SCC growth behaviour appeared stronger at lower temperature due to a reduction of the thermal decomposition of H 2 O 2 . (2) In 100 ppb H 2 O 2 at 453 K and 8 ppm O 2 at 561 K, a single phase oxide of Fe 3 O 4 was observed near the crack tip. In 100 ppb H 2 O 2 at 561 K, however, mixture of NiFe 2 O 4 , Fe 3 O 4 and Fe 2 O 3 was distributed on the surface of side groove and the crack mouth. When SCC propagated steadily, Fe 3 O 4 was produced near the crack tip. (3) Thermal equilibrium calculation for oxide formation at 561 and 453 K showed that a domain of stable Fe 2 O 3 spreads toward high pH region with decreasing in temperature which seemed to be due to production of Fe 3+ and OH - by thermal decomposition of H 2 O 2 . (authors)

  17. Scaling Studies for High Temperature Test Facility and Modular High Temperature Gas-Cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Richard R. Schult; Paul D. Bayless; Richard W. Johnson; James R. Wolf; Brian Woods

    2012-02-01

    The Oregon State University (OSU) High Temperature Test Facility (HTTF) is an integral experimental facility that will be constructed on the OSU campus in Corvallis, Oregon. The HTTF project was initiated, by the U.S. Nuclear Regulatory Commission (NRC), on September 5, 2008 as Task 4 of the 5-year High Temperature Gas Reactor Cooperative Agreement via NRC Contract 04-08-138. Until August, 2010, when a DOE contract was initiated to fund additional capabilities for the HTTF project, all of the funding support for the HTTF was provided by the NRC via their cooperative agreement. The U.S. Department of Energy (DOE) began their involvement with the HTTF project in late 2009 via the Next Generation Nuclear Plant (NGNP) project. Because the NRC's interests in HTTF experiments were only centered on the depressurized conduction cooldown (DCC) scenario, NGNP involvement focused on expanding the experimental envelope of the HTTF to include steady-state operations and also the pressurized conduction cooldown (PCC).

  18. Scaling Studies for High Temperature Test Facility and Modular High Temperature Gas-Cooled Reactor

    International Nuclear Information System (INIS)

    Schult, Richard R.; Bayless, Paul D.; Johnson, Richard W.; Wolf, James R.; Woods, Brian

    2012-01-01

    The Oregon State University (OSU) High Temperature Test Facility (HTTF) is an integral experimental facility that will be constructed on the OSU campus in Corvallis, Oregon. The HTTF project was initiated, by the U.S. Nuclear Regulatory Commission (NRC), on September 5, 2008 as Task 4 of the 5-year High Temperature Gas Reactor Cooperative Agreement via NRC Contract 04-08-138. Until August, 2010, when a DOE contract was initiated to fund additional capabilities for the HTTF project, all of the funding support for the HTTF was provided by the NRC via their cooperative agreement. The U.S. Department of Energy (DOE) began their involvement with the HTTF project in late 2009 via the Next Generation Nuclear Plant (NGNP) project. Because the NRC's interests in HTTF experiments were only centered on the depressurized conduction cooldown (DCC) scenario, NGNP involvement focused on expanding the experimental envelope of the HTTF to include steady-state operations and also the pressurized conduction cooldown (PCC).

  19. High temperature continuous operation in the HTTR (HP-11). Summary of the test results in the high temperature operation mode

    International Nuclear Information System (INIS)

    Takamatsu, Kuniyoshi; Ueta, Shohei; Sumita, Junya; Goto, Minoru; Nakagawa, Shigeaki; Hamamoto, Shimpei; Tochio, Daisuke

    2010-11-01

    A high temperature (950 degrees C) continuous operation has been performed for 50 days on the HTTR from January to March in 2010, and the potential to supply stable heat of high temperature for hydrogen production for a long time was demonstrated for the first time in the world. JAEA has evaluated the experimental data obtained by this operation and past rated continuous one, and built the database necessary for commercial HTGRs. According to the results, the concentration of FP released from the fuels in the HTTR was a single through triple-digit lower than that in the foreign HTGRs. It became apparent that the fuels used in the HTTR are the best quality in the world. This successful operation could establish technological basis of HTGRs and show potential of nuclear energy as heat source for innovative thermo-chemical-based hydrogen production, emitting greenhouse gases on a 'low-carbon path' for the first time in the world. We have a plan to progress R and D for practical use of hydrogen production system with HTGRs in the future. (author)

  20. 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