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Sample records for high temperature shape

  1. 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

  2. High Work Output Ni-Ti-Pt High Temperature Shape Memory Alloys and Associated Processing Methods

    Science.gov (United States)

    Noebe, Ronald D. (Inventor); Draper, Susan L. (Inventor); Nathal, Michael V. (Inventor); Garg, Anita (Inventor)

    2009-01-01

    According to the invention, compositions of Ni-Ti-Pt high temperature, high force, shape memory alloys are disclosed that have transition temperatures above 100 C.; have narrow hysteresis; and produce a high specific work output.

  3. Broadband, high-resolution investigation of advanced absorption line shapes at high temperature

    Science.gov (United States)

    Schroeder, Paul J.; Cich, Matthew J.; Yang, Jinyu; Swann, William C.; Coddington, Ian; Newbury, Nathan R.; Drouin, Brian J.; Rieker, Gregory B.

    2017-08-01

    Spectroscopic studies of planetary atmospheres and high-temperature processes (e.g., combustion) require absorption line-shape models that are accurate over extended temperature ranges. To date, advanced line shapes, like the speed-dependent Voigt and Rautian profiles, have not been tested above room temperature with broadband spectrometers. We investigate pure water vapor spectra from 296 to 1305 K acquired with a dual-frequency comb spectrometer spanning from 6800 to 7200 c m-1 at a point spacing of 0.0033 c m-1 and absolute frequency accuracy of fall within theoretical predictions, suggesting that this mechanism captures the dominant narrowing physics for these high-temperature conditions.

  4. Transformation Temperatures, Shape Memory and Magnetic Properties of Hafnium Modified Ti-Ta Based High Temperature Shape Memory Alloys

    Science.gov (United States)

    Khan, W. Q.; Wang, Q.; Jin, X.

    2017-02-01

    In this study the modification effect of Hf content on the shape memory properties and magnetic permeability of a 75.5-77Ti-20Ta-3-4.5Hf alloy system has been systematically studied by DSC, three-point bend test, vector network analyzer and XRD. The martensitic transformation temperature, heat of reaction and recovery strain increases with the increase of hafnium and tantalum content. A stable high temperature shape memory effect was observed (Ms = 385-390 °C) during the two thermal cycles between 20 °C and 725 °C. Transformation temperatures and heats of reaction were determined by DSC measurements. Recovery strain was determined by three-point bend testing. Also an alloy, 70Ti-26Ta-4Hf, with higher tantalum content was produced to observe the effect of Ta on the shape memory properties. Permeability increases gradually from 1.671 to 1.919 with increasing content of hafnium modification and remains stable in the frequency range of 450 MHz to 1 GHz.

  5. Shape memory behavior of single crystal and polycrystalline Ni-rich NiTiHf high temperature shape memory alloys

    Science.gov (United States)

    Saghaian, Sayed M.

    NiTiHf shape memory alloys have been receiving considerable attention for high temperature and high strength applications since they could have transformation temperatures above 100 °C, shape memory effect under high stress (above 500 MPa) and superelasticity at high temperatures. Moreover, their shape memory properties can be tailored by microstructural engineering. However, NiTiHf alloys have some drawbacks such as low ductility and high work hardening in stress induced martensite transformation region. In order to overcome these limitations, studies have been focused on microstructural engineering by aging, alloying and processing. Shape memory properties and microstructure of four Ni-rich NiTiHf alloys (Ni50.3Ti29.7Hf20, Ni50.7Ti 29.3Hf20, Ni51.2Ti28.8Hf20, and Ni52Ti28Hf20 (at. %)) were systematically characterized in the furnace cooled condition. H-phase precipitates were formed during furnace cooling in compositions with greater than 50.3Ni and the driving force for nucleation increased with Ni content. Alloy strength increased while recoverable strain decreased with increasing Ni content due to changes in precipitate characteristics. The effects of the heat treatments on the transformation characteristics and microstructure of the Ni-rich NiTiHf shape memory alloys have been investigated. Transformation temperatures are found to be highly annealing temperature dependent. Generation of nanosize precipitates (˜20 nm in size) after three hours aging at 450 °C and 550 °C improved the strength of the material, resulting in a near perfect dimensional stability under high stress levels (> 1500 MPa) with a work output of 20-30 J cm- 3. Superelastic behavior with 4% recoverable strain was demonstrated at low and high temperatures where stress could reach to a maximum value of more than 2 GPa after three hours aging at 450 and 550 °C for alloys with Ni great than 50.3 at. %. Shape memory properties of polycrystalline Ni50.3Ti29.7 Hf20 alloys were studied via

  6. Phase Transformation and Shape Memory Effect of Ti-Pd-Pt-Zr High-Temperature Shape Memory Alloys

    Science.gov (United States)

    Yamabe-Mitarai, Yoko; Takebe, Wataru; Shimojo, Masayuki

    2017-11-01

    To understand the potential of high-temperature shape memory alloys, we have investigated the phase transformation and shape memory effect of Ti-(50 - x)Pt-xPd-5Zr alloys (x = 0, 5, and 15 at.%), which present the B2 structure in the austenite phase and B19 structure in the martensite phase. Their phase transformation temperatures are very high; A f and M f of Ti-50Pt are 1066 and 1012 °C, respectively. By adding Zr and Pd, the phase transition temperatures decrease, ranging between 804 and 994 °C for A f and 590 and 865 °C for M f. Even at the high phase transformation temperature, a maximum recovery ratio of 70% was obtained for one cycle in a thermal cyclic test. A work output of 1.2 J/cm3 was also obtained. The recovery ratio obtained by the thermal cyclic test was less than 70% because the recovery strain was < 1% and a large irrecoverable strain was obtained. The shape recovery was explained by the austenite strength. The training effect was also investigated.

  7. Phase Transformation and Shape Memory Effect of Ti-Pd-Pt-Zr High-Temperature Shape Memory Alloys

    Science.gov (United States)

    Yamabe-Mitarai, Yoko; Takebe, Wataru; Shimojo, Masayuki

    2017-12-01

    To understand the potential of high-temperature shape memory alloys, we have investigated the phase transformation and shape memory effect of Ti-(50 - x)Pt- xPd-5Zr alloys ( x = 0, 5, and 15 at.%), which present the B2 structure in the austenite phase and B19 structure in the martensite phase. Their phase transformation temperatures are very high; A f and M f of Ti-50Pt are 1066 and 1012 °C, respectively. By adding Zr and Pd, the phase transition temperatures decrease, ranging between 804 and 994 °C for A f and 590 and 865 °C for M f. Even at the high phase transformation temperature, a maximum recovery ratio of 70% was obtained for one cycle in a thermal cyclic test. A work output of 1.2 J/cm3 was also obtained. The recovery ratio obtained by the thermal cyclic test was less than 70% because the recovery strain was < 1% and a large irrecoverable strain was obtained. The shape recovery was explained by the austenite strength. The training effect was also investigated.

  8. Microstructures and shape memory characteristics of dual-phase Co-Ni-Ga high-temperature shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Li Yan, E-mail: liyan@buaa.edu.cn [School of Materials Science and Engineering, Beihang University, Beijing 100091 (China)] [Beijing Key Laboratory for Advanced Functional Materials and Thin Film Technology, Beihang University, Beijing 100091 (China); Xin Yan [School of Energy and Power Engineering, North China Electric Power University, Beijing 102206 (China); Chai Liang [School of Materials Science and Engineering, Beihang University, Beijing 100091 (China)] [Beijing Key Laboratory for Advanced Functional Materials and Thin Film Technology, Beihang University, Beijing 100091 (China); Ma Yunqing [Department of Materials Science and Engineering, Xiamen University, Xiamen 361005 (China); Xu Huibin [School of Materials Science and Engineering, Beihang University, Beijing 100091 (China)] [Beijing Key Laboratory for Advanced Functional Materials and Thin Film Technology, Beihang University, Beijing 100091 (China)

    2010-06-15

    The influence of microstructure on mechanical properties and shape memory characteristics of Co-Ni-Ga high-temperature shape memory alloys were investigated in this study. X-ray diffraction, scanning electron microscopy and transmission electron microscopy were employed to detect the microstructures. We found that these alloys were composed of dual phases, a non-modulated tetragonal L1{sub 0} martensite and a face-centered cubic (fcc) {gamma} phase. The martensite was twinned and well self-accommodated. The {gamma} phase was a Co-based solid solution with 30% lower hardness than martensite. Although the fracture mode was intergranular, the strength and plasticity of the alloys increased markedly with the increasing volume fraction of the {gamma} phase. The presence of the {gamma} phase in grain boundaries rather than in the martensite is favorable to shape memory recovery. This was revealed by the maximum shape recovery strain over 5.0% that was obtained in the Co{sub 46}Ni{sub 25}Ga{sub 29} alloy, with the {gamma} phase formed mainly in grain boundaries.

  9. Additive Manufacturing of NiTiHf High Temperature Shape Memory Alloy

    Science.gov (United States)

    Benafan, Othmane; Bigelow, Glen S.; Elahinia, Mohammad; Moghaddam, Narges Shayesteh; Amerinatanzi, Amirhesam; Saedi, Soheil; Toker, Guher Pelin; Karaca, Haluk

    2017-01-01

    Additive manufacturing of a NiTi-20Hf high temperature shape memory alloy (HTSMA) was investigated. A selective laser melting (SLM) process by Phenix3D Systems was used to develop components from NiTiHf powder (of approximately 25-75 m particle fractions), and the thermomechanical response was compared to the conventionally vacuum induction skull melted counterpart. Transformation temperatures of the SLM material were found to be slightly lower due to the additional oxygen pick up from the gas atomization and melting process. The shape memory response in compression was measured for stresses up to 500 MPa, and transformation strains were found to be very comparable (Up to 1.26 for the as-extruded; up to 1.52 for SLM).

  10. Functional and structural fatigue of titanium tantalum high temperature shape memory alloys (HT SMAs)

    Energy Technology Data Exchange (ETDEWEB)

    Niendorf, T., E-mail: Thomas.Niendorf@iwt.tu-freiberg.de [Institute of Materials Engineering, Technische Universität Bergakademie Freiberg, 09599 Freiberg (Germany); Krooß, P. [Lehrstuhl für Werkstoffkunde (Materials Science), University of Paderborn, 33098 Paderborn (Germany); Batyrsina, E. [Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, 30823 Garbsen (Germany); Paulsen, A.; Motemani, Y.; Ludwig, A.; Buenconsejo, P.; Frenzel, J.; Eggeler, G. [Institut für Werkstoffe, Ruhr-Universität Bochum, 44801 Bochum (Germany); Maier, H.J. [Institut für Werkstoffkunde (Materials Science), Leibniz Universität Hannover, 30823 Garbsen (Germany)

    2015-01-03

    Due to their high work output and good mechanical properties, actuators made from shape memory alloys (SMAs) are used in numerous applications. Unfortunately, SMAs such as nickel–titanium (Ni–Ti) can only be employed at temperatures up to about 100 °C. Lately, high-temperature shape memory alloys (HT SMAs) have been introduced to overcome this limitation. Ternary systems based on Ni–Ti have been intensively characterized and alloys are available that can operate at elevated temperatures. However, these alloys either contain substantial amounts of expensive noble elements like platinum and palladium, or the materials are brittle. The titanium–tantalum (Ti–Ta) system has been developed to overcome these issues. Binary Ti–Ta provides relatively high M{sub S} temperature combined with excellent workability, but it suffers from fast cyclic degradation. By alloying with third elements this drawback can be overcome: The ternary Ti–Ta–Al alloy shows overall promising properties as will be shown in the present work. In-situ thermo-mechanical cycling experiments were conducted and allowed for evaluation of the factors affecting the functional and structural fatigue of this alloy. Functional fatigue is dominated by ω-phase evolution, while structural fatigue is triggered by an interplay of ω-phase induced embrittlement and deformation constraints imposed by unsuitable texture. In addition, a concept for fatigue life extension proposed very recently for binary Ti–Ta, is demonstrated to be also applicable for the ternary Ti–Ta–Al.

  11. Thermodynamic Properties of a Double Ring-Shaped Quantum Dot at Low and High Temperatures

    Science.gov (United States)

    Khordad, R.; Sedehi, H. R. Rastegar

    2018-02-01

    In this work, we study thermodynamic properties of a GaAs double ring-shaped quantum dot under external magnetic and electric fields. To this end, we first solve the Schrödinger equation and obtain the energy levels and wave functions, analytically. Then, we calculate the entropy, heat capacity, average energy and magnetic susceptibility of the quantum dot in the presence of a magnetic field using the canonical ensemble approach. According to the results, it is found that the entropy is an increasing function of temperature. At low temperatures, the entropy increases monotonically with raising the temperature for all values of the magnetic fields and it is independent of the magnetic field. But, the entropy depends on the magnetic field at high temperatures. The entropy also decreases with increasing the magnetic field. The heat capacity and magnetic susceptibility show a peak structure. The heat capacity reduces with increasing the magnetic field at low temperatures. The magnetic susceptibility shows a transition between diamagnetic and paramagnetic below for T<4 K. The transition temperature depends on the magnetic field.

  12. Cyclic degradation of titanium-tantalum high-temperature shape memory alloys - The role of dislocation activity and chemical decomposition

    OpenAIRE

    Niendorf, T.; Krooß, P.; Somsen, C.; Rynko, R.; Paulsen, A.; Batyrshina, E.; Frenzel, J.; G. Eggeler; Maier, Hans Jürgen

    2015-01-01

    Titanium-tantalum shape memory alloys (SMAs) are promising candidates for actuator applications at elevated temperatures. They may even succeed in substituting ternary nickel-titanium high temperature SMAs, which are either extremely expensive or difficult to form. However, titanium-tantalum alloys show rapid functional and structural degradation under cyclic thermo-mechanical loading. The current work reveals that degradation is not only governed by the evolution of the ω-phase. Dislocation ...

  13. Processing of Ni30Pt20Ti50 High-Temperature Shape-Memory Alloy Into Thin Rod Demonstrated

    Science.gov (United States)

    Noebe, Ronald D.; Draper, Susan L.; Biles, Tiffany A.; Leonhardt, Todd

    2005-01-01

    High-temperature shape-memory alloys (HTSMAs) based on nickel-titanium (NiTi) with significant ternary additions of palladium (Pd), platinum (Pt), gold (Au), or hafnium (Hf) have been identified as potential high-temperature actuator materials for use up to 500 C. These materials provide an enabling technology for the development of "smart structures" used to control the noise, emissions, or efficiency of gas turbine engines. The demand for these high-temperature versions of conventional shape-memory alloys also has been growing in the automotive, process control, and energy industries. However these materials, including the NiPtTi alloys being developed at the NASA Glenn Research Center, will never find widespread acceptance unless they can be readily processed into useable forms.

  14. Transformation behavior and shape memory properties of Ti{sub 50}Ni{sub 15}Pd{sub 25}Cu{sub 10} high temperature shape memory alloy at various aging temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Rehman, Saif ur, E-mail: saifur.rehman@smme.nust.edu.pk [School of Mechanical and Manufacturing Engineering, National University of Science and Technology, Islamabad (Pakistan); Khan, Mushtaq [School of Mechanical and Manufacturing Engineering, National University of Science and Technology, Islamabad (Pakistan); Nusair Khan, A.; Ali, Liaqat; Zaman, Sabah; Waseem, Muhammad [Institute of Industrial Control System, Rawalpindi (Pakistan); Ali, Liaqat; Jaffery, Syed Husain Imran [School of Mechanical and Manufacturing Engineering, National University of Science and Technology, Islamabad (Pakistan)

    2014-12-01

    This research presents an insight into the effect of various aging temperatures on the microstructure, hardness, phase transformation behavior and shape memory properties of Ti{sub 50}Ni{sub 15}Pd{sub 25}Cu{sub 10} high temperature shape memory alloy. The aging temperature was varied from 350 °C to 750 °C, whereas the shape memory properties were evaluated at 100–500 MPa. It was observed that the mentioned properties were strongly dependent on the aging temperatures. Based on the results obtained from scanning electron microscopy, X-ray diffractometry, microhardness testing, differential scanning calorimetry and thermomechanical testing, the aging temperatures can be divided into three ranges. At low aging temperatures (350 °C and below), the properties of the alloy remained the same as were found for solution treated sample, however at intermediate aging temperatures (400–600 °C) the properties of the alloy were changed significantly. Due to the formation of precipitates, the hardness was increased, whereas the phase transformation temperatures and work output were decreased considerably. The recovery ratio was found to be improved for intermediate aging temperatures. At high aging temperatures (650 °C and above), the hardness was decreased and the phase transformation temperatures were increased. Phase transformation temperature at the aging temperature of 750 °C was found to be increased significantly as compared to solution treated sample.

  15. Deformation and Phase Transformation Processes in Polycrystalline NiTi and NiTiHf High Temperature Shape Memory Alloys

    Science.gov (United States)

    Benafan, Othmane

    2012-01-01

    The deformation and transformation mechanisms of polycrystalline Ni49.9Ti50.1 and Ni50.3Ti29.7Hf20 (in at.%) shape memory alloys were investigated by combined experimental and modeling efforts aided by an in situ neutron diffraction technique at stress and temperature. The thermomechanical response of the low temperature martensite, the high temperature austenite phases, and changes between these two states during thermomechanical cycling were probed and reported. In the cubic austenite phase, stress-induced martensite, deformation twinning and slip processes were observed which helped in constructing a deformation map that contained the limits over which each of the identified mechanisms was dominant. Deformation of the monoclinic martensitic phase was also investigated where the microstructural changes (texture, lattice strains, and phase fractions) during room-temperature deformation and subsequent thermal cycling were compared to the bulk macroscopic response. When cycling between these two phases, the evolution of inelastic strains, along with the shape setting procedures were examined and used for the optimization of the transformation properties as a function of deformation levels and temperatures. Finally, this work was extended to the development of multiaxial capabilities at elevated temperatures for the in situ neutron diffraction measurements of shape memory alloys on the VULCAN Diffractometer at Oak Ridge National Laboratory.

  16. A high-temperature shape memory alloy sensor for combustion monitoring and control

    Science.gov (United States)

    Shaw, Greg S.; Snyder, Joseph T.; Prince, Troy S.; Willett, Michael C.

    2005-05-01

    Innovations in the use of thin film SMA materials have enabled the development of a harsh environment pressure sensor useful for combustion monitoring and control. Development of such active combustion control has been driven by rising fuel costs and environmental pressures. Active combustion control, whether in diesel, spark ignited or turbine engines requires feedback to the engine control system in order to adjust the quantity, timing, and placement of fuel charges. To be fully effective, sensors must be integrated into each engine in a manner that will allow continuous combustion monitoring (turbine engines) or monitoring of each discrete combustion event (diesel and SI engines). To date, the sensors available for detection of combustion events and processes have suffered from one or more of three problems: 1) Low sensitivity: The sensors are unable to provide and adequate signal-to-noise ratio in the high temperature and electrically noisy environment of the engine compartment. Attempts to overcome this difficulty have focused on heat removal and/or temperature compensation or more challenging high temperature electronics. 2) Low reliability: Sensors and/or sensor packages have been unable to withstand the engine environment for extended periods of time. Issues have included gross degradation and more subtle issues such as migration of dopants in semiconductor sensor materials. 3) High cost: The materials that have been used, the package concepts employed, and the required support electronics have all contributed to the high cost of the few sensor systems available. Prices have remained high due to the limited demand associated with the poor reliability and the high price itself. Ternary titanium nickel alloys, with platinum group metal substitution for the nickel, are deposited as thin films on MEMS-based diaphragms and patterned to form strain gages of a standard metal film configuration. The strain induced phase transformation of the SMA is used as a

  17. High temperature deformation behavior and processing map for a nickel-titanium shape memory alloy

    Science.gov (United States)

    Yin, Xiang-Qian; Lee, Sang-Won; Li, Yan-Feng; Park, Chan-Hee; Mi, Xu-Jun; Yeom, Jong-Taek

    2017-09-01

    The hot deformation behavior of 49.2Ti-50.8Ni shape memory alloy was studied using hot compressive deformation testing in the temperature range of 1023-1323 K and at strain rates of 0.01-10 s-1. The work-hardening rate was induced to analyze the stress-strain curves, and the critical stress σc and the dynamic recovery saturation stress σsat were measured which can be specified approximately by the expressions: σsat-1.12σp and σc-0.86σp. An Arrhenius model was calculated to describe the relationship between peak stress and the Z parameter. The relationship between deformation activation energy, the deformation conditions and the effect of Ni component in a binary TiNi alloy on the activation energy were discussed in this work. With the help of electron backscattering diffraction, a connected mode dynamic recrystallization microstructure was confirmed in peak efficiency regimes (850 °C & 0.01 s-1 and 1050 °C & 10 s-1) of the processing map.

  18. Influence of microstructure on the shape memory properties of two titanium-lean, nickel-titanium-platinum high temperature shape memory alloys

    Science.gov (United States)

    Hudish, Grant A.

    Because of NiTi's superior properties (work output, strength, ductility, recoverable strain, etc.) it is the base system of choice for development of derivative high-temperature shape memory alloys (HTSMAs). Ternary additions of Hf, Zr, Pt, Pd, and Au can be made, in quantities greater than ≈ 10 at.%, to increase the transformation temperature of Ni-Ti based SMAs. Pt as an alloying addition is attractive because of (1) its efficiency in raising the martensitic transformation temperature, (2) the relatively stable properties during thermal cycling of Pt-containing Nitinol (NiTi), and (3) the high work outputs of Ni-Ti-Pt alloys relative to other HTSMAs. Platinum containing samples of NiTi were thermally processed to explore the utility of Ti-lean precipitates for matrix strengthening and stabilization of shape memory properties during thermomechanical cycling. Two alloys, Ti48.5Ni30.5Pt 21 and Ti49.5Ni29.5Pt21, were heat treated for 1, 5, 24 and 100h at 500, 550, 600, 650, and 700°C and examined using SEM, EDS, DTA, XRD and TEM techniques. Two relevant precipitate phases, the PL and Ti2(Ni,Pt)3 phases, were identified, characterized and the thermodynamic stability and relevant behavior during thermal processing determined. Samples were then subjected to thermomechanical testing that consisted of two parts, (1) two thermal cycles (75°C to 500°C to 75°C) each at stresses of 0, 50, 100, 150, 200, 250, and 300MPa, and (2) 100 thermal cycles at 200MPa. With this combination of systematic microstructural characterization and isobaric thermal cycling, the link between microstructure and shape memory performance was made. The influence the PL and Ti2(Ni,Pt)3 phases have on properties such as martensitic transformation temperatures, transformation strain, and accumulated irrecoverable strain are explained and discussed. Specifically, it was found that the P L-phase suppresses transformation temperatures and strains through a matrix strengthening effect, but also

  19. Flame Shapes of Fuel Droplet Could in High Temperature Gaseous Environment under Micro-gravity

    Science.gov (United States)

    Enomoto, Hiroshi; Nagata, Hitoshi; Segawa, Daisuke; Kadota, Toshikazu

    In order to investigate the spray combustion mechanism, a new methodology (Fine Wire Sustaining method) was established. Fine wires of 14µm in diameter were used to sustain the droplets. Any arrangement of the droplets could be performed with this method. In this study, 33 fuel droplets arranged in symmetrically were subjected to the quiescent high temperature air in an electric furnace. The temperature of the environment air was about 1000K. Fuel was n-eicosane and the mean droplet diameter was 0.58mm. The standard deviation of the droplet diameter was 0.02mm. A high-speed video camera of 250ftp was provided to observe the auto-ignition and flames of fuel droplet clouds. The experiments were done at atmospheric pressure using the JAMIC drop shaft that provides 10 seconds of effective period of time for the micro-gravity. As the results, the time histories of the diameter of the particle flames had maximum and that of the diameter of the group flame had the minimum.

  20. Vacuum Plasma Spray Formed High Transition Temperature Shape Memory Alloys Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Smart materials control of aero-surfaces based on shape memory alloys (SMA) is seeing increased use for improving of future subsonic fixed wing aircraft aero-surface...

  1. Fourcross shaped metamaterial filters fabricated from high temperature superconducting YBCO and Au thin films for terahertz waves

    Science.gov (United States)

    Demirhan, Y.; Alaboz, H.; Nebioğlu, M. A.; Mulla, B.; Akkaya, M.; Altan, H.; Sabah, C.; Ozyuzer, L.

    2017-07-01

    In this study, we present a new, unique fourcross shaped metamaterial terahertz (THz) filter fabricated from both gold thin films and YBa2Cu3O7-d high T c superconducting thin films. A commercial electromagnetic simulation software, CST Microwave Studio, is used to design and optimize the metamaterial filter structures. The proposed fourcross shaped rectangular filter structure consists of periodic metallic rings where strip lines are located at the sides of the ring. Fourcross metamaterial filters are fabricated by using e-beam lithography and ion beam etching techniques. Terahertz time-domain spectroscopy measurements validated the design predictions for both the center frequencies and bandwidths of the resonances due to the fourcross structures. The resonance switching of the transmission spectra was investigated by lowering the temperature below the critical transition temperature. This resonance switching effect is not observed in filters made up of metals. This novel fourcross rectangular resonator with a temperature-dependent resonance behavior holds great potential for active, tunable and low loss THz devices for imaging, sensing, and detection applications.

  2. Characterization of Ternary NiTiPd High-Temperature Shape-Memory Alloys under Load-Biased Thermal Cycling

    Science.gov (United States)

    Bigelow, Glen S.; Padula, Santo A.; Noebe, Ronald D.; Garg, Anita; Gaydosh, Darrell

    2010-01-01

    While NiTiPd alloys have been extensively studied for proposed use in high-temperature shape-memory applications, little is known about the shape-memory response of these materials under stress. Consequently, the isobaric thermal cyclic responses of five (Ni,Pd)49.5Ti50.5 alloys with constant stoichiometry and Pd contents ranging from 15 to 46 at. pct were investigated. From these tests, transformation temperatures, transformation strain (which is proportional to work output), and unrecovered strain per cycle (a measure of dimensional instability) were determined as a function of stress for each alloy. It was found that increasing the Pd content over this range resulted in a linear increase in transformation temperature, as expected. At a given stress level, work output decreased while the amount of unrecovered strain produced during each load-biased thermal cycle increased with increasing Pd content, during the initial thermal cycles. However, continued thermal cycling at constant stress resulted in a saturation of the work output and nearly eliminated further unrecovered strain under certain conditions, resulting in stable behavior amenable to many actuator applications.

  3. Correlation between Mechanical Behavior and Actuator-type Performance of Ni-Ti-Pd High-temperature Shape Memory Alloys

    Science.gov (United States)

    Bigelow, Glen S.; Padula, Santo A., II; Garg, Anita; Noebe, Ronald D.

    2007-01-01

    High-temperature shape memory alloys in the NiTiPd system are being investigated as lower cost alternatives to NiTiPt alloys for use in compact solid-state actuators for the aerospace, automotive, and power generation industries. A range of ternary NiTiPd alloys containing 15 to 46 at.% Pd has been processed and actuator mimicking tests (thermal cycling under load) were used to measure transformation temperatures, work behavior, and dimensional stability. With increasing Pd content, the work output of the material decreased, while the amount of permanent strain resulting from each load-biased thermal cycle increased. Monotonic isothermal tension testing of the high-temperature austenite and low temperature martensite phases was used to partially explain these behaviors, where a mismatch in yield strength between the austenite and martensite phases was observed at high Pd levels. Moreover, to further understand the source of the permanent strain at lower Pd levels, strain recovery tests were conducted to determine the onset of plastic deformation in the martensite phase. Consequently, the work behavior and dimensional stability during thermal cycling under load of the various NiTiPd alloys is discussed in relation to the deformation behavior of the materials as revealed by the strain recovery and monotonic tension tests.

  4. Effects of Novel Fin Shape of High Temperature Heat Exchanger on 1 kW Class Stirling Engine

    Energy Technology Data Exchange (ETDEWEB)

    Ahn, Joon; Kim, Seok Yeon [Kookmin Univ., Seoul (Korea, Republic of)

    2017-08-15

    In this research, numerical analysis was carried out on novel and existing fins, adjusted in terms of factors such as length, spacing, and angle, of a high-temperature heat exchanger for a 1 kW class Stirling engine, designed as a prime mover for a domestic cogeneration system. The performance improvement as a result of shape optimization was confirmed with numerical analysis by including the air preheater, which was not considered during optimization. However, a negative heat flux was observed in the cylinder head portion. This phenomenon was clarified by analyzing the exhaust gas and wall surface temperature of the combustion chamber. Furthermore, assuming an ideal cycle, the effects of heat transfer enhancement on the thermodynamic cycle and system performance were predicted.

  5. Effects of Stoichiometry on Transformation Temperatures and Actuator-Type Performance of NiTiPd and NiTiPdX High-Temperature Shape Memory Alloys

    Science.gov (United States)

    Bigelow, Glen S.; Gaydosh, Darrell; Garg, Anita; Padula, Santo A., II; Noebe, Ronald D.

    2007-01-01

    High-temperature shape memory NiTiPd and NiTiPdX (X=Au, Pt, Hf) alloys were produced with titanium equivalent (Ti+Hf) compositions of 50.5, 50.0, 49.5, and 49.0 at.%. Thermo-mechanical testing in compression was used to evaluate the transformation temperatures, transformation strain, work output, and permanent deformation behavior of each alloy to study the effects of quaternary alloying and stoichiometry on high-temperature shape memory alloy behavior. Microstructural evaluation showed the presence of second phases for all alloy compositions. No load transformation temperatures in the stoichiometric alloys were relatively unchanged by Au and Pt substitutions, while the substitution of Hf for Ti causes a drop in transformation temperatures. The NiTiPd, NiTiPdAu and NiTiPdHf alloys exhibited transformation temperatures that were highest in the Ti-rich compositions, slightly lower at stoichiometry, and significantly reduced when the Ti equivalent composition was less than 50 at.%. For the NiTiPdPt alloy, transformation temperatures were highest for the Ti-rich compositions, lowest at stoichiometry, and slightly higher in the Ni-rich composition. When thermally cycled under constant stresses of up to 300 MPa, all of the alloys had transformation strains, and therefore work outputs, which increased with increasing stress. In each series of alloys, the transformation strain and thus work output was highest for stoichiometric or Ti-rich compositions while permanent strain associated with the constant-load thermal cycling was lowest for alloys with Ni-equivalent-rich compositions. Based on these results, basic rules for optimizing the composition of NiTiPd alloys for actuator performance will be discussed.

  6. High Damping of Lightweight TiNi-Ti2Ni Shape Memory Composites for Wide Temperature Range Usage

    Science.gov (United States)

    Yang, Bing; Luo, Zheng; Yuan, Bin; Liu, Jiangwen; Gao, Yan

    2017-10-01

    A bimodal porous TiNi-Ti2Ni shape memory alloy composite (SMAC) with 59% porosity was fabricated by sintering Ti-46at.%Ni elemental powders with pore-forming agent. The porous TiNi-Ti2Ni SMAC contains two irregular pores of about 400 and 120 μm. We investigated the microstructure and pore morphology correlated with the mechanical properties and damping capacities of the SMAC. Ti2Ni intermetallic phases with size of 1-3 μm were homogeneously distributed in the TiNi matrix. The porous TiNi-Ti2Ni SMAC exhibits exceptionally high inverse mechanical quality factor ( Q -1) of 0.25 at < 40 °C, which is among the highest value reported for porous/dense shape memory alloys or composites to best of our knowledge, and it shows very high compressive fracture strain of about 25%. Moreover, the fabricated porous SMAC at relatively low strain amplitude can exhibit considerable high Q -1 of 0.06 0.11 for a wide range of temperature between - 90 and 200 °C, which is attributed to the stress concentration distribution provided by the bimodal structure of pores and the massive interfaces between pore/matrix and TiNi/Ti2Ni. These porous SMACs can be an ideal candidate for using as a lightweight damping material in the energy-saving applications.

  7. Structural modification and twinning stress reduction in a high-temperature Ni-Mn-Ga magnetic shape memory alloy

    Science.gov (United States)

    Pagounis, E.; Chulist, R.; Lippmann, T.; Laufenberg, M.; Skrotzki, W.

    2013-09-01

    Mechanical and synchrotron diffraction experiments were performed to investigate the temperature dependent structural changes in a Ni-Mn-Ga single crystal. The initial sample exhibits a mixture of seven-layered (7M) and non-modulated (NM) martensites at room temperature. Compression along ⟨100⟩ resulted in a strain of 18%, indicating a stress-induced intermartensitic transformation from the 7M to the NM phase. The thermally induced intermartensitic transformation follows the sequence 5M→7M→NM during cooling from the austenite phase. The structural changes are quantitatively reflected in the mechanical response. A twinning stress of 3.8 MPa is measured at 90 °C, which is the lowest reported in high-temperature Ni-Mn-Ga structures.

  8. Shape Memory Characteristics of Ti(sub 49.5)Ni(sub 25)Pd(sub 25)Sc(sub 0.5) High-Temperature Shape Memory Alloy After Severe Plastic Deformation

    Science.gov (United States)

    Atli, K. C.; Karaman, I.; Noebe, R. D.; Garg, A.; Chumlyakov, Y. I.; Kireeva, I. V.

    2011-01-01

    A Ti(49.5)Ni25Pd25Sc(0.5) high-temperature shape memory alloy is thermomechanically processed to obtain enhanced shape-memory characteristics: in particular, dimensional stability upon repeated thermal cycles under constant loads. This is accomplished using severe plastic deformation via equal channel angular extrusion (ECAE) and post-processing annealing heat treatments. The results of the thermomechanical experiments reveal that the processed materials display enhanced shape memory response, exhibiting higher recoverable transformation and reduced irrecoverable strain levels upon thermal cycling compared with the unprocessed material. This improvement is attributed to the increased strength and resistance of the material against defect generation upon phase transformation as a result of the microstructural refinement due to the ECAE process, as supported by the electron microscopy observations.

  9. Dopamine-Incorporated Dual Bioactive Electroactive Shape Memory Polyurethane Elastomers with Physiological Shape Recovery Temperature, High Stretchability, and Enhanced C2C12 Myogenic Differentiation.

    Science.gov (United States)

    Zhao, Xin; Dong, Ruonan; Guo, Baolin; Ma, Peter X

    2017-09-06

    Soft tissue engineering needs elastic biomaterials not only mimicking the elasticity of soft tissue but also possessing multiple bioactivity to promote cell adhesion, proliferation, and differentiation, which still remain ongoing challenges. Herein, we synthesized a series of dopamine-incorporated dual bioactive electroactive shape memory polyurethane elastomers by combining the properties of elastomeric poly(citric acid-co-polycaprolactone) (CA-PCL) polyurethane elastomer, bioactive dopamine (DA), and electroactive aniline hexamer (AH). The chemical structures, electroactivity, conductivity, thermal properties, hydrophilicity and hydration ability, mechanical properties, and degradability of the polyurethane elastomers were systematically characterized. The elastomers showed excellent shape fixity ratio and shape recovery ability under physiological conditions. The elastomers' elongation and stress were tailored by the AH content, whereas the hydrophilicity and hydration ability of the elastomers were adjusted by the content of DA and AH, as well as the doping state of AH. The viability and proliferation results of C2C12 cells seeded on the elastomers showed their excellent cytocompatibility. Additionally, by analyzing the protein and gene level, the promotion effect on myogenic differentiation of C2C12 cells by these elastomers compared to that by control groups (PCL80 000, CA-PCL elastomer, and CA-PCL elastomer with the DA segment) was demonstrated. Furthermore, the results from subcutaneous implantation confirmed the elastomers' mild host response in vivo. These results represent that these dopamine-incorporated dual bioactive electroactive shape memory polyurethane elastomers are promising candidates for soft tissue regeneration that is sensitive to electrical signals.

  10. Characterization of Ni19.5Ti50.5Pd25Pt5 High-Temperature Shape Memory Alloy Springs and their Potential Application in Aeronautics

    Science.gov (United States)

    Stebner, Aaron; Padula, Santo A.; Noebe, Ronald D.

    2008-01-01

    Shape memory alloys (SMAs) have been used as actuators in many different industries since the discovery of the shape memory effect, but the use of SMAs as actuation devices in aeronautics has been limited due to the temperature constraints of commercially available materials. Consequently, work is being done at NASA's Glenn Research Center to develop new SMAs capable of being used in high temperature environments. One of the more promising high-temperature shape memory alloys (HTSMAs) is Ni19.5Ti50.5Pd25Pt5. Recent work has shown that this material is capable of being used in operating environments of up to 250 C. This material has been shown to have very useful actuation capabilities, demonstrating repeatable strain recoveries up to 2.5% in the presence of an externally applied load. Based on these findings, further work has been initiated to explore potential applications and alternative forms of this alloy, such as springs. Thus, characterization of Ni19.5Ti50.5Pd25Pt5 springs, including their mechanical response and how variations in this response correlate to changes in geometric parameters, are discussed. The effects of loading history, or training, on spring behavior were also investigated. A comparison of the springs with wire actuators is made and the benefits of using one actuator form as opposed to the other discussed. These findings are used to discuss design considerations for a surge-control mechanism that could be used in the centrifugal compressor of a T-700 helicopter engine.

  11. On the Recovery Stress of a Ni50.3Ti29.7Hf20 High Temperature Shape Memory Alloy

    Science.gov (United States)

    Benafan, O.; Noebe, R. D.; Padula, S. A., II; Bigelow, G. S.; Gaydosh, D. J.; Garg, A.; Halsmer, T. J.

    2015-01-01

    Recovery stress in shape memory alloys (SMAs), also known as blocking stress, is an important property generally obtained during heating under a dimensional constraint as the material undergoes the martensitic phase transformation. This property has been instinctively utilized in most SMA shape-setting procedures, and has been used in numerous applications such as fastening and joining, rock splitting, safety release mechanisms, reinforced composites, medical devices, and many other applications. The stress generation is also relevant to actuator applications where jamming loads (e.g., in case the actuator gets stuck and is impeded from moving) need to be determined for proper hardware sizing. Recovery stresses in many SMA systems have been shown to reach stresses in the order of 800 MPa, achieved via thermo-mechanical training such as pre-straining, heat treatments or other factors. With the advent of high strength, high temperature SMAs, recovery stress data has been rarely probed, and there is no information pertinent to the magnitudes of these stresses. Thus, the purpose of this work is to investigate the recovery stress capability of a precipitation strengthened, Ni50.3Ti29.7Hf20 (at.) high temperature SMA in uniaxial tension and compression. This material has been shown to exhibit outstanding strength and stability during constant-stress, thermal cycling, but no data exists on constant-strain thermal cycling. Several training routines were implemented as part of this work including isothermal pre-straining, isobaric thermal cycling, and isothermal cyclic training routines. Regardless of the training method used, the recovery stress was characterized using constant-strain (strain-controlled condition) thermal cycling between the upper and lower cycle temperatures. Preliminary results indicate recovery stresses in excess of 1.5 GPa were obtained after a specific training routine. This stress magnitude is significantly higher than conventional NiTi stress

  12. Comparative Analysis of the Effects of Severe Plastic Deformation and Thermomechanical Training on the Functional Stability of Ti50.5Ni24.5Pd25 High-Temperature Shape Memory Alloy

    Science.gov (United States)

    Atli, K. C.; Karaman, I.; Noebe, R. D.; Maier, H. J.

    2010-01-01

    We compare the effectiveness of a conventional thermomechanical training procedure and severe plastic deformation via equal channel angular extrusion to achieve improved functional stability in a Ti50.5Ni24.5Pd25 high-temperature shape memory alloy. Thermomechanical testing indicates that both methods result in enhanced shape memory characteristics, such as reduced irrecoverable strain and thermal hysteresis. The mechanisms responsible for the improvements are discussed in light of microstructural findings from transmission electron microscopy.

  13. Temperature compensation in piezoelectric energy harvesters using shape memory alloys

    Science.gov (United States)

    Rhimi, Mohamed; Lajnef, Nizar

    2011-04-01

    Harvested vibration energy is typically considered as an alternative power source for sensors' networks for health and usage monitoring in civil and mechanical structures. The longevity, and hence the efficacy, of these sensors is severely limited by the levels of generated power. Piezoelectric vibration harvesters have been widely used given their energy conversion ability and relatively high mechanical to electrical coupling properties. Several techniques can be applied to improve these properties and to cancel external environmental effects such as temperature variations. In this paper, the temperature compensation of the response characteristics of a bimorph cantilever Lead zirconate titanate (PZT) piezoelectric beam, through a combination with shape memory alloys, is studied. A mathematical model, based on onedimensional linear piezoelectricity equations and one dimensional constitutive behavior of shape memory alloys, is derived. The model describes the effect of temperature deviations on the theoretical harvestable energy levels as well as the compensation methodology. Proof of concept experimental results are also presented. The voltage response transfer functions are measured at different temperatures to show the induced effect by shape memory alloys.

  14. Effect of Thermomechanical Processing on the Microstructure, Properties, and Work Behavior of a Ti50.5 Ni29.5 Pt20 High-Temperature Shape Memory Alloy

    Science.gov (United States)

    Noebe, Ronald; Draper, Susan; Gaydosh, Darrell; Garga, Anita; Lerch, Brad; Penney, Nicholas; Begelow, Glen; Padula, Santo, II; Brown, Jeff

    2006-01-01

    TiNiPt shape memory alloys are particularly promising for use as solid state actuators in environments up to 300 C, due to a reasonable balance of properties, including acceptable work output. However, one of the challenges to commercializing a viable high-temperature shape memory alloy (HTSMA) is to establish the appropriate primary and secondary processing techniques for fabrication of the material in a required product form such as rod and wire. Consequently, a Ti(50.5)Ni(29.5)Pt20 alloy was processed using several techniques including single-pass high-temperature extrusion, multiple-pass high-temperature extrusion, and cold drawing to produce bar stock, thin rod, and fine wire, respectively. The effects of heat treatment on the hardness, grain size, room temperature tensile properties, and transformation temperatures of hot- and cold-worked material were examined. Basic tensile properties as a function of temperature and the strain-temperature response of the alloy under constant load, for the determination of work output, were also investigated for various forms of the Ti(50.5)Ni(29.5)Pt20 alloy, including fine wire.

  15. 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.

  16. Parametric analysis and temperature effect of deployable hinged shells using shape memory polymers

    Science.gov (United States)

    Tao, Ran; Yang, Qing-Sheng; He, Xiao-Qiao; Liew, Kim-Meow

    2016-11-01

    Shape memory polymers (SMPs) are a class of intelligent materials, which are defined by their capacity to store a temporary shape and recover an original shape. In this work, the shape memory effect of SMP deployable hinged shell is simulated by using compiled user defined material subroutine (UMAT) subroutine of ABAQUS. Variations of bending moment and strain energy of the hinged shells with different temperatures and structural parameters in the loading process are given. The effects of the parameters and temperature on the nonlinear deformation process are emphasized. The entire thermodynamic cycle of SMP deployable hinged shell includes loading at high temperature, load carrying with cooling, unloading at low temperature and recovering the original shape with heating. The results show that the complicated thermo-mechanical deformation and shape memory effect of SMP deployable hinge are influenced by the structural parameters and temperature. The design ability of SMP smart hinged structures in practical application is prospected.

  17. Critical temperature for shape transitions in excited nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Martin, V. [Analisis Numerico, Facultad de Informatica, Universidad Politecnica de Madrid, E-28660, Madrid (Spain); Egido, J.L.; Robledo, L.M. [Departamento de Fisica Teorica, Universidad Autonoma de Madrid, E-28049, Madrid (Spain)

    2004-04-01

    The behavior of shell effects with temperature is studied within the framework of the finite-temperature Hartree-Fock-Bogoliubov theory with the Gogny force. Thermal shape fluctuations in the quadrupole degree of freedom are taken into account in the frame of the Landau theory. Numerical results for the superfluid-to-normal and deformed-to-spherical phase transitions are presented for the nucleus {sup 164}Er. We find that the critical temperature for the deformed-spherical shape transition is much lowered when the thermal shape fluctuations are considered. (orig.)

  18. High temperature battery. Hochtemperaturbatterie

    Energy Technology Data Exchange (ETDEWEB)

    Bulling, M.

    1992-06-04

    To prevent heat losses of a high temperature battery, it is proposed to make the incoming current leads in the area of their penetration through the double-walled insulating housing as thermal throttle, particularly spiral ones.

  19. High temperature structural silicides

    Energy Technology Data Exchange (ETDEWEB)

    Petrovic, J.J.

    1997-03-01

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

  20. High-temperature superconductors

    CERN Document Server

    Saxena, Ajay Kumar

    2010-01-01

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

  1. High Temperature Electrolysis

    DEFF Research Database (Denmark)

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

    2015-01-01

    High temperature electrolysis of carbon dioxide, or co-electrolysis of carbon dioxide and steam, has a great potential for carbon dioxide utilisation. A solid oxide electrolysis cell (SOEC), operating between 500 and 900. °C, is used to reduce carbon dioxide to carbon monoxide. If steam is also...... input to the cell then hydrogen is produced giving syngas. This syngas can then be further reacted to form hydrocarbon fuels and chemicals. Operating at high temperature gives much higher efficiencies than can be achieved with low temperature electrolysis. Current state of the art SOECs utilise a dense...

  2. High Temperature QCD

    CERN Document Server

    Lombardo, M P

    2012-01-01

    I review recent results on QCD at high temperature on a lattice. Steady progress with staggered fermions and Wilson type fermions allow a quantitative description of hot QCD whose accuracy in many cases parallels that of zero temperature studies. Simulations with chiral quarks are coming of age, and togheter with theoretical developments trigger interesting developments in the analysis of the critical region. Issues related with the universality class of the chiral transition and the fate of the axial symmetry are discussed in the light of new numerical and analytical results. Transport coefficients and analysis of bottomonium spectra compare well with results of heavy ion collisions at RHIC and LHC. Model field theories, lattice simulations and high temperature systematic expansions help building a coherent picture of the high temperature phase of QCD. The (strongly coupled) Quark Gluon Plasma is heavily investigated, and asserts its role as an inspiring theoretical laboratory.

  3. Highly efficient high temperature electrolysis

    DEFF Research Database (Denmark)

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

    2008-01-01

    High temperature electrolysis of water and steam may provide an efficient, cost effective and environmentally friendly production of H-2 Using electricity produced from sustainable, non-fossil energy sources. To achieve cost competitive electrolysis cells that are both high performing i.e. minimum...... electrolysis is favourable from a thermodynamic point of view, because a part of the required energy can be supplied as thermal heat, and the activation barrier is lowered increasing the H-2 production rate. Only two types of cells operating at high temperature (above 200 degrees C) have been described...... electrolysis using SOECs is competitive to H-2 production from fossil fuels at electricity prices below 0.02-0.03 is an element of per kWh. Though promising SOEC results on H-2 production have been reported a substantial R&D is still required to obtain inexpensive, high performing and long-term stable...

  4. Wireless and passive temperature indicator utilizing the large hysteresis of magnetic shape memory alloys

    Science.gov (United States)

    Bergmair, Bernhard; Liu, Jian; Huber, Thomas; Gutfleisch, Oliver; Suess, Dieter

    2012-07-01

    An ultra-low cost, wireless magnetoelastic temperature indicator is presented. It comprises a magnetostrictive amorphous ribbon, a Ni-Mn-Sn-Co magnetic shape memory alloy with a highly tunable transformation temperature, and a bias magnet. It allows to remotely detect irreversible changes due to transgressions of upper or lower temperature thresholds. Therefore, the proposed temperature indicator is particularly suitable for monitoring the temperature-controlled supply chain of, e.g., deep frozen and chilled food or pharmaceuticals.

  5. High temperature superconducting materials

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-02-01

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

  6. High temperature 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

  7. High temperature superconductivity: Proceedings

    Energy Technology Data Exchange (ETDEWEB)

    Bedell, K.S.; Coffey, D. (Los Alamos National Lab., NM (USA)); Meltzer, D.E. (Florida Univ., Gainesville, FL (USA)); Pines, D. (Illinois Univ., Urbana, IL (USA)); Schrieffer, J.R. (California Univ., Santa Barbara, CA (USA)) (eds.)

    1990-01-01

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

  8. 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.

  9. Characterization of a New Phase and Its Effect on the Work Characteristics of a Near-Stoichiometric Ni30Pt20Ti50 High-Temperature Shape Memory Alloy (HTSMA)

    Science.gov (United States)

    Garg, A.; Gaydosh, D.; Noebe, R.D.; Padula II, Santo; Bigelow, G.S.; Kaufman, M.; Kovarik, L.; Mills, M.J.; Diercks, D.; McMurray, S.

    2008-01-01

    A new phase observed in a nominal Ni30Pt20Ti50 (at.%) high temperature shape memory alloy has been characterized using transmission electron microscopy and 3-D atom probe tomography. This phase forms homogeneously in the B2 austenite matrix by a nucleation and growth mechanism and results in a concomitant increase in the martensitic transformation temperature of the base alloy. Although the structure of this phase typically contains a high density of faults making characterization difficult, it appears to be trigonal (-3m point group) with a(sub o) approx. 1.28 nm and c(sub o) approx. 1.4 nm. Precipitation of this phase increases the microhardness of the alloy substantially over that of the solution treated and quenched single-phase material. The effect of precipitation strengthening on the work characteristics of the alloy has been explored through load-biased strain-temperature testing in the solution-treated condition and after aging at 500 C for times ranging from 1 to 256 hours. Work output was found to increase in the aged alloy as a result of an increase in transformation strain, but was not very sensitive to aging time. The amount of permanent deformation that occurred during thermal cycling under load was small but increased with increasing aging time and stress. Nevertheless, the dimensional stability of the alloy at short aging times (1-4 hours) was still very good making it a potentially useful material for high-temperature actuator applications.

  10. High temperature future

    Energy Technology Data Exchange (ETDEWEB)

    Sheinkopf, K. [Solar Energy Research and Education Foundation, Washington, DC (United States)

    1994-09-01

    During the past few years, there have been dramatic accomplishments and success of high temperature solar thermal systems and significant development of these systems. High temperature technologies, about 500 F and higher, such as dish engines, troughs, central receiver power towers and solar process heat systems, have been tested, demonstrated and used in an array of applications, including many cost-effective utility bulk power production and demand side supply projects in the United States. Large systems provide power and hot water to prisons, schools, nursing homes and other institutions. Joint ventures with industry, utility projects, laboratory design assistance and other activities are building a solid industry of US solar thermal systems ready for use today.

  11. Determining Recoverable and Irrecoverable Contributions to Accumulated Strain in a NiTiPd High-Temperature Shape Memory Alloy During Thermomechanical Cycling

    Science.gov (United States)

    Monroe, J. A.; Karaman, I.; Lagoudas, D. C.; Bigelow, G.; Noebe, R. D.; Padula, S., II

    2011-01-01

    When Ni(29.5)Ti(50.5)Pd30 shape memory alloy is thermally cycled under stress, significant strain can accumulate due to elasticity, remnant oriented martensite and plasticity. The strain due to remnant martensite can be recovered by further thermal cycling under 0 MPa until the original transformation-induced volume change and martensite coefficient of thermal expansion are obtained. Using this technique, it was determined that the 8.15% total accumulated strain after cycling under 200 MPa consisted of 0.38%, 3.97% and 3.87% for elasticity, remnant oriented martensite and creep/plasticity, respectively.

  12. Elastic Shape Memory Hybrids Programmable at Around Body-Temperature for Comfort Fitting

    Directory of Open Access Journals (Sweden)

    Tao Xi Wang

    2017-12-01

    Full Text Available A series of silicone based elastic shape memory hybrids are fabricated. Their shape memory performance, mechanical behaviors at room temperature with/without programming and during fitting at 37 °C are investigated. It is found that these materials have good shape memory effect and are always highly elastic. At 37 °C, there are 10 min or more for fitting. Thus, it is concluded that this type of material has great potential as an elastic shape memory material for comfort fitting.

  13. High Temperature Piezoelectric Drill

    Science.gov (United States)

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

    2012-01-01

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

  14. 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 ...

  15. Structure and phase transformations in copper-alloyed rapidly melt-quenched Ni50Ti32Hf18-based alloys with high-temperature shape memory effect

    Science.gov (United States)

    Pushin, A. V.; Pushin, V. G.; Kuranova, N. N.; Kourov, N. I.; Kuntsevich, T. E.; Makarov, V. V.; Uksusnikov, A. N.

    2017-10-01

    Methods of transmission and scanning electron microscopy, chemical microanalysis, electron diffraction, and X-ray diffraction have been used to carry out the comparative study of the structure and chemical and phase composition of thin ribbons of four quasi-binary alloys (Ni50Ti32Hf18, Ni45Ti32Hf18Cu5, Ni35Ti32Hf18Cu15, and Ni25Ti32Hf18Cu25) obtained in the amorphous state by rapid quenching from the melt by jet spinning. The critical temperatures of the devitrification and B2 ↔ B19' martensitic transformation of the alloys have been determined based on the data of temperature dependences of the electrical resistivity. The specific features of the formation of the ultrafine-grained structure upon the devitrification and of the phase transformations have been studied depending on the heat-treatment regimes and chemical composition of the alloys (concentration of copper atoms).

  16. 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.

  17. High Temperature Aquifer Storage

    Science.gov (United States)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2016-04-01

    Combined heat and power generation (CHP) is highly efficient because excess heat is used for heating and/or process energy. However, the demand of heat energy varies considerably throughout the year while the demand for electrical energy is rather constant. It seems economically and ecologically highly beneficial for municipalities and large power consumers such as manufacturing plants to store excess heat in groundwater aquifers and to recuperate this energy at times of higher demand. Within the project High Temperature Aquifer Storage, scientists investigate storage and recuperation of excess heat energy into the bavarian Malm aquifer. Apart from high transmissivity and favorable pressure gradients, the hydrochemical conditions are crucial for long-term operation. An enormous technical challenge is the disruption of the carbonate equilibrium - modeling results indicated a carbonate precipitation of 10 - 50 kg/d in the heat exchangers. The test included five injection pulses of hot water (60 °C up to 110 °C) and four tracer pulses, each consisting of a reactive and a conservative fluorescent dye, into a depth of about 300 m b.s.l. resp. 470 m b.s.l. Injection and production rates were 15 L/s. To achieve the desired water temperatures, about 4 TJ of heat energy were necessary. Electrical conductivity, pH and temperature were recorded at a bypass where also samples were taken. A laboratory container at the drilling site was equipped for analysing the concentration of the dyes and the major cations at sampling intervals of down to 15 minutes. Additional water samples were taken and analysed in the laboratory. The disassembled heat exchanger prooved that precipitation was successfully prevented by adding CO2 to the water before heating. Nevertheless, hydrochemical data proved both, dissolution and precipitation processes in the aquifer. This was also suggested by the hydrochemical modelling with PhreeqC and is traced back to mixture dissolution and changing

  18. High-order epistasis shapes evolutionary trajectories.

    Science.gov (United States)

    Sailer, Zachary R; Harms, Michael J

    2017-05-01

    High-order epistasis-where the effect of a mutation is determined by interactions with two or more other mutations-makes small, but detectable, contributions to genotype-fitness maps. While epistasis between pairs of mutations is known to be an important determinant of evolutionary trajectories, the evolutionary consequences of high-order epistasis remain poorly understood. To determine the effect of high-order epistasis on evolutionary trajectories, we computationally removed high-order epistasis from experimental genotype-fitness maps containing all binary combinations of five mutations. We then compared trajectories through maps both with and without high-order epistasis. We found that high-order epistasis strongly shapes the accessibility and probability of evolutionary trajectories. A closer analysis revealed that the magnitude of epistasis, not its order, predicts is effects on evolutionary trajectories. We further find that high-order epistasis makes it impossible to predict evolutionary trajectories from the individual and paired effects of mutations. We therefore conclude that high-order epistasis profoundly shapes evolutionary trajectories through genotype-fitness maps.

  19. High Temperature Hybrid Elastomers

    Science.gov (United States)

    Drake, Kerry Anthony

    Conventional high temperature elastomers are produced by chain polymerization of olefinic or fluorinated olefinic monomers. Ultimate thermal stabilities are limited by backbone bond strengths, lower thermal stability of cross-link sites relative to backbone bonds, and depolymerization or "unzipping" at high temperatures. In order to develop elastomers with enhanced thermal stability, hybrid thermally cross-linkable polymers that consisted only of organic-inorganic and aromatic bonds were synthesized and evaluated. The addition of phenylethynyl or phenylacetylinic functional groups to these polymers resulted in conversion of the polymers into high temperature elastomers when cross-linked by thermal curing. Polyphenyoxydiphenylsilanes were synthesized via several different condensation reactions. Results of these synthetic reactions, which utilized both hydroquinone and biphenol as monomers, were systematically evaluated to determine the optimal synthetic conditions for subsequent endcapping reactions. It was determined that dichlorodiphenylsilane condensations with biphenol in toluene or THF were best suited for this work. Use of excess dichlorodiphenylsilane yielded polymers of appropriate molecular weights with terminal reactive chlorosilane groups that could be utilized for coupling with phenylethynyl reagents in a subsequent reaction. Two new synthetic routes were developed to endcap biphenoxysilanes with ethynyl containing substituents, to yield polymers with cross-linkable end groups. Endcapping by lithiumphenylacetylide and 4[(4-fluorophenylethynyl))phenol yielded two new polymers that could be thermally cross-linked on heating above 300 °C. Successful endcapping was verified chemically by 13C NMR, FTIR and Raman analysis. Exothermic peaks consistent with ethynyl curing reactions were observed in endcapped polymers by DSC. A new diacetylinic polymer was prepared through reaction of 4,4'-buta-1,3-diyne-1,4-diyldiphenol and dichlorodiphenylsilane. This

  20. Impact of temperature-velocity distribution on fusion neutron peak shape

    Science.gov (United States)

    Munro, D. H.; Field, J. E.; Hatarik, R.; Peterson, J. L.; Hartouni, E. P.; Spears, B. K.; Kilkenny, J. D.

    2017-05-01

    Doppler broadening of the 14 MeV DT and 2.45 MeV DD fusion neutron lines has long been our best measure of temperature in a burning plasma. At the National Ignition Facility (NIF), yields are high enough and our neutron spectrometers accurate enough that we see finer details of the peak shape. For example, we can measure the shift of the peak due to the bulk motion of the plasma, and we see indications of non-thermal broadening, skew, and kurtosis of the peak caused by the variations of temperature and fluid velocity during burn. We can also distinguish spectral differences among several lines of sight. This paper will review the theory of fusion neutron line shape, show examples of non-Gaussian line shapes and directional variations in NIF data, and describe detailed spectral shapes we see in radiation-hydrodynamics simulations of implosions.

  1. 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.

  2. 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

  3. Effect of Al alloying on the martensitic temperature in Ti-Ta shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Ferrari, Alberto; Rogal, Jutta; Drautz, Ralf [Interdisciplinary Centre for Advanced Materials Simulation, Ruhr-Universitaet Bochum (Germany)

    2017-07-01

    Ti-Ta-based alloys are promising candidates as high temperature shape memory alloys (HTSMAs) for actuators and superelastic applications. The shape memory mechanism involves a martensitic transformation between the low-temperature α'' phase (orthorhombic) and the high-temperature β phase (body-centered cubic). In order to prevent the degradation of the shape memory effect, Ti-Ta needs to be alloyed with further elements. However, this often reduces the martensitic temperature M{sub s}, which is usually strongly composition dependent. The aim of this work is to analyze how the addition of a third element to Ti-Ta alloys affects M{sub s} by means of electronic structure calculations. In particular, it will be investigated how alloying Al to Ti-Ta alters the relative stability of the α'' and β phases. This understanding will help to identify new alloy compositions featuring both a stable shape memory effect and elevated transformation temperatures.

  4. 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.

  5. 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

  6. Life at High Temperatures

    Indian Academy of Sciences (India)

    2005-09-15

    Sep 15, 2005 ... or more in the vicinity of geothermal vents in the deep sea and the plant Tidestromia oblongifolia (Amaranthaceae) found in Death. Valley in California, where the hottest temperature on earth ever recorded during 43 consecutive days in 1917 was >48 °C. (Guinness Book of W orId Records, 1999).

  7. High temperature materials; Materiaux a hautes temperatures

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2003-07-01

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

  8. 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...

  9. Stretchable degradable and electroactive shape memory copolymers with tunable recovery temperature enhance myogenic differentiation.

    Science.gov (United States)

    Deng, Zexing; Guo, Yi; Zhao, Xin; Li, Longchao; Dong, Ruonan; Guo, Baolin; Ma, Peter X

    2016-12-01

    Development of flexible degradable electroactive shape memory polymers (ESMPs) with tunable switching temperature (around body temperature) for tissue engineering is still a challenge. Here we designed and synthesized a series of shape memory copolymers with electroactivity, super stretchability and tunable recovery temperature based on poly(ε-caprolactone) (PCL) with different molecular weight and conductive amino capped aniline trimer, and demonstrated their potential to enhance myogenic differentiation from C2C12 myoblast cells. We characterized the copolymers by Fourier transform infrared spectroscopy (FT-IR), proton nuclear magnetic resonance ((1)H NMR), cyclic voltammetry (CV), ultraviolet-visible spectroscopy (UV-vis), differential scanning calorimetry (DSC), shape memory test, tensile test and in vitro enzymatic degradation study. The electroactive biodegradable shape memory copolymers showed great elasticity, tunable recovery temperature around 37°C, and good shape memory properties. Furthermore, proliferation and differentiation of C2C12 myoblasts were investigated on electroactive copolymers films, and they greatly enhanced the proliferation, myotube formation and related myogenic differentiation genes expression of C2C12 myoblasts compared to the pure PCL with molecular weight of 80,000. Our study suggests that these electroactive, highly stretchable, biodegradable shape memory polymers with tunable recovery temperature near the body temperature have great potential in skeletal muscle tissue engineering application. Conducting polymers can regulate cell behavior such cell adhesion, proliferation, and differentiation with or without electrical stimulation. Therefore, they have great potential for electrical signal sensitive tissue regeneration. Although conducting biomaterials with degradability have been developed, highly stretchable and electroactive degradable copolymers for soft tissue engineering have been rarely reported. On the other hand, shape

  10. High-Temperature Superconductors

    CERN Document Server

    Saxena, Ajay Kumar

    2012-01-01

    This book presents the current knowledge about superconductivity in high Tc cuprate superconductors. There is a large scientific interest and great potential for technological applications. The book discusses all the aspects related to all families of cuprate superconductors discovered so far. Beginning with the phenomenon of superconductivity, the book covers: the structure of cuprate HTSCs, critical currents, flux pinning, synthesis of HTSCs, proximity effect and SQUIDs, possible applications of high Tc superconductors and theories of superconductivity. Though a high Tc theory is still awaited, this book describes the present scenario and BCS and RVB theories. The second edition was  significantly extended by including film-substrate lattice matching and buffer layer considerations in thin film HTSCs, brick-wall microstructure in the epitaxial films, electronic structure of the CuO2 layer in cuprates, s-wave and d-wave coupling in HTSCs and possible scenarios of theories of high Tc superconductivity.

  11. High Temperature Electrostrictive Ceramics Project

    Data.gov (United States)

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

  12. High Temperature Surface Interactions

    Science.gov (United States)

    1989-11-01

    oxidation rate of "pure SiC* in air (from compilation of data by Schlichting6). For T < 14001C, partial cristobalite formation; T > 1400"C, decreased...aluminium content is high enough, the beta phase percolates and contains a dispersion of -- Ni particles. Such a tructure is certainly less favourable

  13. Temperature Condition and Spherical Shell Shape Variation of Space Gauge-Alignment Spacecraft

    Directory of Open Access Journals (Sweden)

    V. S. Zarubin

    2016-01-01

    Full Text Available A high precision spherical shell is one of the geometrical shape embodiments of a gaugealignment spacecraft to determine and control a radar channel energy potential of the ground-based complex for the traffic control of space objects. Passive relays of signals and some types of smallsized instrumentation standard reflectors used for radar gauge and alignment have the same shape. Orbits of the considered spacecraft can be either circular with a height of about 1000 km, including those close to the polar, or elliptical with an apogee of up to 2200 km.In case there is no thermal control system in spacecrafts of these types the solar radiation is a major factor to define the thermal state of a spherical shell in the illuminated orbit area. With the shell in fixed position with respect to direction towards the Sun an arising uneven temperature distribution over its surface leads to variation of the spherically ideal shell shape, which may affect the functional characteristics of the spacecraft. The shell rotation about an axis perpendicular to the direction towards the Sun may reduce an unevenness degree of the temperature distribution.The uneven temperature distribution over the spherical shell surface in conditions of the lowEarth space and this unevenness impact on the shell shape variation against its spherical shape can be quantively estimated by the appropriate methods of mathematical modeling using modification of a previously developed mathematical model to describe steady temperature state of such shell on the low-Earth orbit. The paper considers the shell made from a polymeric composite material. Its original spherical shape is defined by rather low internal pressure. It is assumed that equipment in the shell, if any, is quite small-sized. This allows us to ignore its impact on the radiative transfer in the shell cavity. Along with defining the steady temperature distribution over the shell surface at its fixed orientation with respect to

  14. Effects of temperature and maternal and grandmaternal age on wing shape in parthenogenetic Drosophila mercatorum

    DEFF Research Database (Denmark)

    Kjaersgaard, Anders; Faurby, Soren; Andersen, Ditte Holm

    2007-01-01

    The effects a stressful developmental temperature and maternal and grandmaternal age was investigated on plasticity of wing shape, using the Procrustes method, in two parthenogenetic strains of Drosophila mercatorum. Shape was significantly modified by both factors. Maternal and grandmaternal age...

  15. (Krauss) at constant high temperatures

    African Journals Online (AJOL)

    Snail Research Unit of the SAMRC and Department of Zoology, Potchefstroom University for CHE,. Potchefstroom. The survival of the freshwater snail species Bulinus africanus, Bulinus g/obosus and Biompha/aria pfeifferi at extreme high temperatures was experimentally investigated. Snails were exposed to temperatures ...

  16. 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...

  17. High Temperature Bell Motor Project

    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...

  18. 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...

  19. STUDY OF NUMERICAL MODELING OF SHAPE DEFORMING ZONE OF DIES, DURING DRAWING HIGH CARBON STEEL WIRE TO THE TEMPERATURE AND THE STRESS-STRAIN STATE IN THE WIRE AND DIE

    Directory of Open Access Journals (Sweden)

    O. L. Bobarikin

    2012-01-01

    Full Text Available Investigation by numerical modeling of influence of the form of deforming zone of die at drawing of steel high- carbon wire on temperature and strained-deformed state in wire and die is carried out.

  20. Land surface temperature shaped by urban fractions in megacity region

    Science.gov (United States)

    Zhang, Xiaoxuan; Hu, Yonghong; Jia, Gensuo; Hou, Meiting; Fan, Yanguo; Sun, Zhongchang; Zhu, Yuxiang

    2017-02-01

    Large areas of cropland and natural vegetation have been replaced by impervious surfaces during the recent rapid urbanization in China, which has resulted in intensified urban heat island effects and modified local or regional warming trends. However, it is unclear how urban expansion contributes to local temperature change. In this study, we investigated the relationship between land surface temperature (LST) change and the increase of urban land signals. The megacity of Tianjin was chosen for the case study because it is representative of the urbanization process in northern China. A combined analysis of LST and urban land information was conducted based on an urban-rural transect derived from Landsat 8 Thermal Infrared Sensor (TIRS), Terra Moderate Resolution Imaging Spectrometer (MODIS), and QuickBird images. The results indicated that the density of urban land signals has intensified within a 1-km2 grid in the urban center with an impervious land fraction >60 %. However, the construction on urban land is quite different with low-/mid-rise buildings outnumbering high-rise buildings in the urban-rural transect. Based on a statistical moving window analysis, positive correlation ( R 2 > 0.9) is found between LST and urban land signals. Surface temperature change (ΔLST) increases by 0.062 °C, which was probably caused by the 1 % increase of urbanized land (ΔIF) in this case region.

  1. 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.

  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. HIgh Temperature Photocatalysis over Semiconductors

    Science.gov (United States)

    Westrich, Thomas A.

    Due in large part to in prevalence of solar energy, increasing demand of energy production (from all sources), and the uncertain future of petroleum energy feedstocks, solar energy harvesting and other photochemical systems will play a major role in the developing energy market. This dissertation focuses on a novel photochemical reaction process: high temperature photocatalysis (i.e., photocatalysis conducted above ambient temperatures, T ≥ 100°C). The overarching hypothesis of this process is that photo-generated charge carriers are able to constructively participate in thermo-catalytic chemical reactions, thereby increasing catalytic rates at one temperature, or maintaining catalytic rates at lower temperatures. The photocatalytic oxidation of carbon deposits in an operational hydrocarbon reformer is one envisioned application of high temperature photocatalysis. Carbon build-up during hydrocarbon reforming results in catalyst deactivation, in the worst cases, this was shown to happen in a period of minutes with a liquid hydrocarbon. In the presence of steam, oxygen, and above-ambient temperatures, carbonaceous deposits were photocatalytically oxidized over very long periods (t ≥ 24 hours). This initial experiment exemplified the necessity of a fundamental assessment of high temperature photocatalytic activity. Fundamental understanding of the mechanisms that affect photocatalytic activity as a function of temperatures was achieved using an ethylene photocatalytic oxidation probe reaction. Maximum ethylene photocatalytic oxidation rates were observed between 100 °C and 200 °C; the maximum photocatalytic rates were approximately a factor of 2 larger than photocatalytic rates at ambient temperatures. The loss of photocatalytic activity at temperatures above 200 °C is due to a non-radiative multi-phonon recombination mechanism. Further, it was shown that the fundamental rate of recombination (as a function of temperature) can be effectively modeled as a

  4. 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.

  5. High temperature superconductor accelerator magnets

    OpenAIRE

    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 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 ...

  6. High Temperature Superconductor Accelerator Magnets

    OpenAIRE

    Van Nugteren, Jeroen; ten Kate, Herman; de Rijk, Gijs; Dhalle, Marc

    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 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 ...

  7. High-Temperature Optical Sensor

    Science.gov (United States)

    Adamovsky, Grigory; Juergens, Jeffrey R.; Varga, Donald J.; Floyd, Bertram M.

    2010-01-01

    A high-temperature optical sensor (see Figure 1) has been developed that can operate at temperatures up to 1,000 C. The sensor development process consists of two parts: packaging of a fiber Bragg grating into a housing that allows a more sturdy thermally stable device, and a technological process to which the device is subjected to in order to meet environmental requirements of several hundred C. This technology uses a newly discovered phenomenon of the formation of thermally stable secondary Bragg gratings in communication-grade fibers at high temperatures to construct robust, optical, high-temperature sensors. Testing and performance evaluation (see Figure 2) of packaged sensors demonstrated operability of the devices at 1,000 C for several hundred hours, and during numerous thermal cycling from 400 to 800 C with different heating rates. The technology significantly extends applicability of optical sensors to high-temperature environments including ground testing of engines, flight propulsion control, thermal protection monitoring of launch vehicles, etc. It may also find applications in such non-aerospace arenas as monitoring of nuclear reactors, furnaces, chemical processes, and other hightemperature environments where other measurement techniques are either unreliable, dangerous, undesirable, or unavailable.

  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. 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)

    Wate Bakker

    2004-03-01

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

  11. Nonlinear plasmonics at high temperatures

    Science.gov (United States)

    Sivan, Yonatan; Chu, Shi-Wei

    2017-01-01

    We solve the Maxwell and heat equations self-consistently for metal nanoparticles under intense continuous wave (CW) illumination. Unlike previous studies, we rely on experimentally-measured data for metal permittivity for increasing temperature and for the visible spectral range. We show that the thermal nonlinearity of the metal can lead to substantial deviations from the predictions of the linear model for the temperature and field distribution and, thus, can explain qualitatively the strong nonlinear scattering from such configurations observed experimentally. We also show that the incompleteness of existing data of the temperature dependence of the thermal properties of the system prevents reaching a quantitative agreement between the measured and calculated scattering data. This modeling approach is essential for the identification of the underlying physical mechanism responsible for the thermo-optical nonlinearity of the metal and should be adopted in all applications of high-temperature nonlinear plasmonics, especially for refractory metals, for both CW and pulsed illumination.

  12. Nonlinear plasmonics at high temperatures

    Directory of Open Access Journals (Sweden)

    Sivan Yonatan

    2016-10-01

    Full Text Available We solve the Maxwell and heat equations self-consistently for metal nanoparticles under intense continuous wave (CW illumination. Unlike previous studies, we rely on experimentally-measured data for metal permittivity for increasing temperature and for the visible spectral range. We show that the thermal nonlinearity of the metal can lead to substantial deviations from the predictions of the linear model for the temperature and field distribution and, thus, can explain qualitatively the strong nonlinear scattering from such configurations observed experimentally. We also show that the incompleteness of existing data of the temperature dependence of the thermal properties of the system prevents reaching a quantitative agreement between the measured and calculated scattering data. This modeling approach is essential for the identification of the underlying physical mechanism responsible for the thermo-optical nonlinearity of the metal and should be adopted in all applications of high-temperature nonlinear plasmonics, especially for refractory metals, for both CW and pulsed illumination.

  13. Rapid folding of DNA into nanoscale shapes at constant temperature

    National Research Council Canada - National Science Library

    Sobczak, Jean-Philippe J; Martin, Thomas G; Gerling, Thomas; Dietz, Hendrik

    2012-01-01

    .... Unfolding occurred in apparent equilibrium at higher temperatures than those for folding. Folding at optimized constant temperatures enabled the rapid production of three-dimensional DNA objects with yields that approached 100...

  14. Mapping morphological shape as a high-dimensional functional curve.

    Science.gov (United States)

    Fu, Guifang; Huang, Mian; Bo, Wenhao; Hao, Han; Wu, Rongling

    2017-01-06

    Detecting how genes regulate biological shape has become a multidisciplinary research interest because of its wide application in many disciplines. Despite its fundamental importance, the challenges of accurately extracting information from an image, statistically modeling the high-dimensional shape and meticulously locating shape quantitative trait loci (QTL) affect the progress of this research. In this article, we propose a novel integrated framework that incorporates shape analysis, statistical curve modeling and genetic mapping to detect significant QTLs regulating variation of biological shape traits. After quantifying morphological shape via a radius centroid contour approach, each shape, as a phenotype, was characterized as a high-dimensional curve, varying as angle θ runs clockwise with the first point starting from angle zero. We then modeled the dynamic trajectories of three mean curves and variation patterns as functions of θ Our framework led to the detection of a few significant QTLs regulating the variation of leaf shape collected from a natural population of poplar, Populus szechuanica var tibetica This population, distributed at altitudes 2000-4500 m above sea level, is an evolutionarily important plant species. This is the first work in the quantitative genetic shape mapping area that emphasizes a sense of 'function' instead of decomposing the shape into a few discrete principal components, as the majority of shape studies do. © The Author 2017. Published by Oxford University Press. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  15. Shape-selective dependence of room temperature ferromagnetism induced by hierarchical ZnO nanostructures.

    Science.gov (United States)

    Motaung, D E; Mhlongo, G H; Nkosi, S S; Malgas, G F; Mwakikunga, B W; Coetsee, E; Swart, H C; Abdallah, H M I; Moyo, T; Ray, S S

    2014-06-25

    We report on the room temperature ferromagnetism of various highly crystalline zinc oxide (ZnO) nanostructures, such as hexagonally shaped nanorods, nanocups, nanosamoosas, nanoplatelets, and hierarchical nano "flower-like" structures. These materials were synthesized in a shape-selective manner using simple microwave assisted hydrothermal synthesis. Thermogravimetric analyses demonstrated the as-synthesized ZnO nanostructures to be stable and of high purity. Structural analyses showed that the ZnO nanostructures are polycrystalline and wurtzite in structure, without any secondary phases. Combination of electron paramagnetic resonance, photoluminescence, and X-ray photoelectron spectroscopy studies revealed that the zinc vacancies (VZn) and singly ionized oxygen vacancies (VO(+)) located mainly on the ZnO surface are the primary defects in ZnO structures. A direct link between ferromagnetism and the relative occupancy of the VZn and VO(+) was established, suggesting that both VZn and VO(+) on the ZnO surface plays a vital role in modulating ferromagnetic behavior. An intense structure- and shape-dependent ferromagnetic signal with an effective g-value of >2.0 and a sextet hyperfine structure was shown. Moreover, a novel low field microwave absorption signal was observed and found to increase with an increase in microwave power and temperature.

  16. 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.

  17. 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.

  18. Properties of high temperature SQUIDS

    Energy Technology Data Exchange (ETDEWEB)

    Falco, C. M.; Wu, C. T.

    1978-01-01

    A review is given of the present status of weak links and dc and rf biased SQUIDs made with high temperature superconductors. A method for producing reliable, reproducible devices using Nb/sub 3/Sn is outlined, and comments are made on directions future work should take.

  19. High-temperature flooding injury

    Science.gov (United States)

    This problem, also called scald, is most serious in the hot desert valleys of the southwestern United States, subtropical regions in eastern Australia, and western Asia and northern Africa (Middle East) where fields are established and irrigated under high temperatures. The disorder also occurs to...

  20. High temperature thermoelectric energy conversion

    Science.gov (United States)

    Wood, Charles

    1987-01-01

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

  1. High-order epistasis shapes evolutionary trajectories.

    OpenAIRE

    Sailer, Zachary R.; Harms, Michael J.

    2017-01-01

    High-order epistasis-where the effect of a mutation is determined by interactions with two or more other mutations-makes small, but detectable, contributions to genotype-fitness maps. While epistasis between pairs of mutations is known to be an important determinant of evolutionary trajectories, the evolutionary consequences of high-order epistasis remain poorly understood. To determine the effect of high-order epistasis on evolutionary trajectories, we computationally removed high-order epis...

  2. High-order epistasis shapes evolutionary trajectories

    OpenAIRE

    Sailer, Zachary R.

    2017-01-01

    High-order epistasis?where the effect of a mutation is determined by interactions with two or more other mutations?makes small, but detectable, contributions to genotype-fitness maps. While epistasis between pairs of mutations is known to be an important determinant of evolutionary trajectories, the evolutionary consequences of high-order epistasis remain poorly understood. To determine the effect of high-order epistasis on evolutionary trajectories, we computationally removed high-order epis...

  3. 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.

  4. High Temperature Composite Heat Exchangers

    Science.gov (United States)

    Eckel, Andrew J.; Jaskowiak, Martha H.

    2002-01-01

    High temperature composite heat exchangers are an enabling technology for a number of aeropropulsion applications. They offer the potential for mass reductions of greater than fifty percent over traditional metallics designs and enable vehicle and engine designs. Since they offer the ability to operate at significantly higher operating temperatures, they facilitate operation at reduced coolant flows and make possible temporary uncooled operation in temperature regimes, such as experienced during vehicle reentry, where traditional heat exchangers require coolant flow. This reduction in coolant requirements can translate into enhanced range or system payload. A brief review of the approaches and challengers to exploiting this important technology are presented, along with a status of recent government-funded projects.

  5. Shape rheocasting of high purity aluminium

    CSIR Research Space (South Africa)

    Curle, UA

    2011-03-01

    Full Text Available ) The HPDC component was a plate of dimensions 100 x 55 x 6 mm excluding the biscuit and the runner. The top-end of the plate was sectioned in the transverse orientation, mounted in bakelite hot mounting resin and finally mechanical polished with colloidal...?Pro MC v6.0 imaging software was used to record the microstructure. The whole HPDC casting (including the plate, runner and biscuit) that was produced for this temperature curve is shown in Figure 2. The surface of the plate is somewhat rough...

  6. Fast pyrolysis of biomass at high temperatures

    DEFF Research Database (Denmark)

    Trubetskaya, Anna

    . Different particle shapes of beechwood and leached wheat straw chars produced in the drop tube reactor which have similar potassium content suggested a stronger influence of the major biomass cell wall compounds (cellulose, hemicellulose, lignin and extractives) and silicates on the char morphology than...... multi core structures compared to pinewood soot generated at 1400°C, combining both single and multi core particles.Beechwood and wheat straw soot samples had multi and single core particles at both temperatures.In thermogravimetric analysis, the maximal reaction rate of pinewood soot was shifted...... 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...

  7. 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.

  8. 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.

  9. High temperature structural sandwich panels

    Science.gov (United States)

    Papakonstantinou, Christos G.

    High strength composites are being used for making lightweight structural panels that are being employed in aerospace, naval and automotive structures. Recently, there is renewed interest in use of these panels. The major problem of most commercial available sandwich panels is the fire resistance. A recently developed inorganic matrix is investigated for use in cases where fire and high temperature resistance are necessary. The focus of this dissertation is the development of a fireproof composite structural system. Sandwich panels made with polysialate matrices have an excellent potential for use in applications where exposure to high temperatures or fire is a concern. Commercial available sandwich panels will soften and lose nearly all of their compressive strength temperatures lower than 400°C. This dissertation consists of the state of the art, the experimental investigation and the analytical modeling. The state of the art covers the performance of existing high temperature composites, sandwich panels and reinforced concrete beams strengthened with Fiber Reinforced Polymers (FRP). The experimental part consists of four major components: (i) Development of a fireproof syntactic foam with maximum specific strength, (ii) Development of a lightweight syntactic foam based on polystyrene spheres, (iii) Development of the composite system for the skins. The variables are the skin thickness, modulus of elasticity of skin and high temperature resistance, and (iv) Experimental evaluation of the flexural behavior of sandwich panels. Analytical modeling consists of a model for the flexural behavior of lightweight sandwich panels, and a model for deflection calculations of reinforced concrete beams strengthened with FRP subjected to fatigue loading. The experimental and analytical results show that sandwich panels made with polysialate matrices and ceramic spheres do not lose their load bearing capability during severe fire exposure, where temperatures reach several

  10. High Temperature Heat Exchanger Project

    Energy Technology Data Exchange (ETDEWEB)

    Anthony E. Hechanova, Ph.D.

    2008-09-30

    The UNLV Research Foundation assembled a research consortium for high temperature heat exchanger design and materials compatibility and performance comprised of university and private industry partners under the auspices of the US DOE-NE Nuclear Hydrogen Initiative in October 2003. The objectives of the consortium were to conduct investigations of candidate materials for high temperature heat exchanger componets in hydrogen production processes and design and perform prototypical testing of heat exchangers. The initial research of the consortium focused on the intermediate heat exchanger (located between the nuclear reactor and hydrogen production plan) and the components for the hydrogen iodine decomposition process and sulfuric acid decomposition process. These heat exchanger components were deemed the most challenging from a materials performance and compatibility perspective

  11. 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.

  12. Accurate thermodynamic relations of the melting temperature of nanocrystals with different shapes and pure theoretical calculation

    Energy Technology Data Exchange (ETDEWEB)

    Zhu, Jinhua; Fu, Qingshan; Xue, Yongqiang, E-mail: xyqlw@126.com; Cui, Zixiang

    2017-05-01

    Based on the surface pre-melting model, accurate thermodynamic relations of the melting temperature of nanocrystals with different shapes (tetrahedron, cube, octahedron, dodecahedron, icosahedron, nanowire) were derived. The theoretically calculated melting temperatures are in relative good agreements with experimental, molecular dynamic simulation and other theoretical results for nanometer Au, Ag, Al, In and Pb. It is found that the particle size and shape have notable effects on the melting temperature of nanocrystals, and the smaller the particle size, the greater the effect of shape. Furthermore, at the same equivalent radius, the more the shape deviates from sphere, the lower the melting temperature is. The value of melting temperature depression of cylindrical nanowire is just half of that of spherical nanoparticle with an identical radius. The theoretical relations enable one to quantitatively describe the influence regularities of size and shape on the melting temperature and to provide an effective way to predict and interpret the melting temperature of nanocrystals with different sizes and shapes. - Highlights: • Accurate relations of T{sub m} of nanocrystals with various shapes are derived. • Calculated T{sub m} agree with literature results for nano Au, Ag, Al, In and Pb. • ΔT{sub m} (nanowire) = 0.5ΔT{sub m} (spherical nanocrystal). • The relations apply to predict and interpret the melting behaviors of nanocrystals.

  13. Very High Temperature Sound Absorption Coating Project

    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...

  14. Nanoscale high-temperature superconductivity

    Energy Technology Data Exchange (ETDEWEB)

    Mohanty, P.; Wei, J.Y.T.; Ananth, V.; Morales, P.; Skocpol, W

    2004-08-01

    We discuss the exciting prospects of studying high-temperature superconductivity in the nanometer scale from the perspective of experiments, theory and simulation. In addition to enabling studies of novel quantum phases in an unexplored regime of system dimensions and parameters, nanoscale high-temperature superconducting structures will allow exploration of fundamental mechanisms with unprecedented insight. The prospects include, spin-charge separation, detection of electron fractionalization via novel excitations such as vison, stripe states and their dynamics, preformed cooper pairs or bose-condensation in the underdoped regime, and other quantum-ordered states. Towards this initiative, we present the successful development of a novel nanofabrication technique for the epitaxial growth of nanoscale cuprates. Combining the techniques of e-beam lithography and nanomachining, we have been able to fabricate the first generation of high-temperature superconducting nanoscale devices, including Y-junctions, four-probe wires and rings. Their initial transport characterization and scanning tunneling microscopy reveal the integrity of the crystal structure, grown on nanometer scale lateral dimensions. Here, we present atomic force micrographs and electrical characterization of a few nanoscale YBa{sub 2}Cu{sub 3}O{sub 7} (YBCO) samples.

  15. High temperature PEM fuel cells

    Science.gov (United States)

    Zhang, Jianlu; Xie, Zhong; Zhang, Jiujun; Tang, Yanghua; Song, Chaojie; Navessin, Titichai; Shi, Zhiqing; Song, Datong; Wang, Haijiang; Wilkinson, David P.; Liu, Zhong-Sheng; Holdcroft, Steven

    There are several compelling technological and commercial reasons for operating H 2/air PEM fuel cells at temperatures above 100 °C. Rates of electrochemical kinetics are enhanced, water management and cooling is simplified, useful waste heat can be recovered, and lower quality reformed hydrogen may be used as the fuel. This review paper provides a concise review of high temperature PEM fuel cells (HT-PEMFCs) from the perspective of HT-specific materials, designs, and testing/diagnostics. The review describes the motivation for HT-PEMFC development, the technology gaps, and recent advances. HT-membrane development accounts for ∼90% of the published research in the field of HT-PEMFCs. Despite this, the status of membrane development for high temperature/low humidity operation is less than satisfactory. A weakness in the development of HT-PEMFC technology is the deficiency in HT-specific fuel cell architectures, test station designs, and testing protocols, and an understanding of the underlying fundamental principles behind these areas. The development of HT-specific PEMFC designs is of key importance that may help mitigate issues of membrane dehydration and MEA degradation.

  16. 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

  17. A micro S-shaped optical fiber temperature sensor based on dislocation fiber splice

    Science.gov (United States)

    Yan, Haitao; Li, Pengfei; Zhang, Haojie; Shen, Xiaoyue; Wang, Yongzhen

    2017-12-01

    We fabricated a simple, compact, and stable temperature sensor based on an S-shaped dislocated optical fiber. The dislocation optical fiber has two splice points, and we obtained the optimal parameters based on the theory and our experiment, such as the dislocation amount and length of the dislocation optical fiber. According to the relationship between the temperature and the peak wavelength shift, the temperature of the environment can be obtained. Then, we made this fiber a micro bending as S-shape between the two dislocation points, and the S-shaped micro bending part could release stress with the change in temperature and reduce the effect of stress on the temperature measurement. This structure could solve the problem of sensor distortion caused by the cross response of temperature and stress. We measured the S-shaped dislocation fiber sensor and the dislocation fiber without S-shape under the same environment and conditions, and the S-shaped dislocation fiber had the advantages of the stable reliability and good linearity.

  18. Low temperature superconductor and aligned high temperature superconductor magnetic dipole system and method for producing high magnetic fields

    Energy Technology Data Exchange (ETDEWEB)

    Gupta, Ramesh; Scanlan, Ronald; Ghosh, Arup K.; Weggel, Robert J.; Palmer, Robert; Anerella, Michael D.; Schmalzle, Jesse

    2017-10-17

    A dipole-magnet system and method for producing high-magnetic-fields, including an open-region located in a radially-central-region to allow particle-beam transport and other uses, low-temperature-superconducting-coils comprised of low-temperature-superconducting-wire located in radially-outward-regions to generate high magnetic-fields, high-temperature-superconducting-coils comprised of high-temperature-superconducting-tape located in radially-inward-regions to generate even higher magnetic-fields and to reduce erroneous fields, support-structures to support the coils against large Lorentz-forces, a liquid-helium-system to cool the coils, and electrical-contacts to allow electric-current into and out of the coils. The high-temperature-superconducting-tape may be comprised of bismuth-strontium-calcium-copper-oxide or rare-earth-metal, barium-copper-oxide (ReBCO) where the rare-earth-metal may be yttrium, samarium, neodymium, or gadolinium. Advantageously, alignment of the large-dimension of the rectangular-cross-section or curved-cross-section of the high-temperature-superconducting-tape with the high-magnetic-field minimizes unwanted erroneous magnetic fields. Alignment may be accomplished by proper positioning, tilting the high-temperature-superconducting-coils, forming the high-temperature-superconducting-coils into a curved-cross-section, placing nonconducting wedge-shaped-material between windings, placing nonconducting curved-and-wedge-shaped-material between windings, or by a combination of these techniques.

  19. 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...

  20. A temperature-responsive network links cell shape and virulence traits in a primary fungal pathogen.

    Directory of Open Access Journals (Sweden)

    Sinem Beyhan

    2013-07-01

    Full Text Available Survival at host temperature is a critical trait for pathogenic microbes of humans. Thermally dimorphic fungal pathogens, including Histoplasma capsulatum, are soil fungi that undergo dramatic changes in cell shape and virulence gene expression in response to host temperature. How these organisms link changes in temperature to both morphologic development and expression of virulence traits is unknown. Here we elucidate a temperature-responsive transcriptional network in H. capsulatum, which switches from a filamentous form in the environment to a pathogenic yeast form at body temperature. The circuit is driven by three highly conserved factors, Ryp1, Ryp2, and Ryp3, that are required for yeast-phase growth at 37°C. Ryp factors belong to distinct families of proteins that control developmental transitions in fungi: Ryp1 is a member of the WOPR family of transcription factors, and Ryp2 and Ryp3 are both members of the Velvet family of proteins whose molecular function is unknown. Here we provide the first evidence that these WOPR and Velvet proteins interact, and that Velvet proteins associate with DNA to drive gene expression. Using genome-wide chromatin immunoprecipitation studies, we determine that Ryp1, Ryp2, and Ryp3 associate with a large common set of genomic loci that includes known virulence genes, indicating that the Ryp factors directly control genes required for pathogenicity in addition to their role in regulating cell morphology. We further dissect the Ryp regulatory circuit by determining that a fourth transcription factor, which we name Ryp4, is required for yeast-phase growth and gene expression, associates with DNA, and displays interdependent regulation with Ryp1, Ryp2, and Ryp3. Finally, we define cis-acting motifs that recruit the Ryp factors to their interwoven network of temperature-responsive target genes. Taken together, our results reveal a positive feedback circuit that directs a broad transcriptional switch between

  1. TEMPERATURE AND ELECTRON DENSITY DIAGNOSTICS OF A CANDLE-FLAME-SHAPED FLARE

    Energy Technology Data Exchange (ETDEWEB)

    Guidoni, S. E. [NASA Goddard Space Flight Center/CUA, Code 674, 8800 Greenbelt Road, Greenbelt, MD 20771 (United States); McKenzie, D. E.; Longcope, D. W.; Yoshimura, K. [Department of Physics, Montana State University, Bozeman, MT 59717-3840 (United States); Plowman, J. E., E-mail: silvina.e.guidoni@nasa.gov [High Altitude Observatory, National Center for Atmospheric Research P.O. Box 3000, Boulder, CO 80307-3000 (United States)

    2015-02-10

    Candle-flame-shaped flares are archetypical structures that provide indirect evidence of magnetic reconnection. A flare resembling Tsuneta's famous 1992 candle-flame flare occurred on 2011 January 28; we present its temperature and electron density diagnostics. This flare was observed with Solar Dynamics Observatory/Atmospheric Imaging Assembly (SDO/AIA), Hinode/X-Ray Telescope (XRT), and Solar Terrestrial Relations Observatory Ahead (STEREO-A)/Extreme Ultraviolet Imager, resulting in high-resolution, broad temperature coverage, and stereoscopic views of this iconic structure. The high-temperature images reveal a brightening that grows in size to form a tower-like structure at the top of the posteruption flare arcade, a feature that has been observed in other long-duration events. Despite the extensive work on the standard reconnection scenario, there is no complete agreement among models regarding the nature of this high-intensity elongated structure. Electron density maps reveal that reconnected loops that are successively connected at their tops to the tower develop a density asymmetry of about a factor of two between the two legs, giving the appearance of ''half-loops''. We calculate average temperatures with a new fast differential emission measure (DEM) method that uses SDO/AIA data and analyze the heating and cooling of salient features of the flare. Using STEREO observations, we show that the tower and the half-loop brightenings are not a line-of-sight projection effect of the type studied by Forbes and Acton. This conclusion opens the door for physics-based explanations of these puzzling, recurrent solar flare features, previously attributed to projection effects. We corroborate the results of our DEM analysis by comparing them with temperature analyses from Hinode/XRT.

  2. 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...

  3. 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.

  4. Proteomics of Rice Grain under High Temperature Stress

    Directory of Open Access Journals (Sweden)

    Toshiaki eMitsui

    2013-03-01

    Full Text Available Recent proteomic analyses revealed dynamic changes of metabolisms during rice grain development. Interestingly, proteins involved in glycolysis, citric acid cycle, lipid metabolism, and proteolysis were accumulated at higher levels in mature grain than those of developing stages. High temperature stress in rice ripening period causes damaged (chalky grains which have loosely packed round shape starch granules. The high temperature stress response on protein expression is complicated, and the molecular mechanism of the chalking of grain is obscure yet. Here, the current state on the proteomics research of rice grain grown under high temperature stress is briefly overviewed.

  5. 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.

  6. High shape recovery Ni–Ti SMA wire produced from electron beam melted ingot

    Energy Technology Data Exchange (ETDEWEB)

    Antunes, A.S. [Instituto Tecnologico de Aeronautica – ITA, 12.228-900, S. J. Campos, SP (Brazil); Instituto Federal de Mato Grosso do Sul – IFMS, 79.331-040, Corumba, MS (Brazil); Tosetti, J.P.V. [Instituto Tecnologico de Aeronautica – ITA, 12.228-900, S. J. Campos, SP (Brazil); Otubo, J., E-mail: jotubo@ita.br [Instituto Tecnologico de Aeronautica – ITA, 12.228-900, S. J. Campos, SP (Brazil)

    2013-11-15

    Highlights: ► It was obtained a remarkable complete shape recovery up to 9% pre-strain. ► Shape recovery higher than 9% was obtained for a pre-strain up to 15%. ► These good results are attributed to a high purity NiTi SMA wire produced from EBM ingot. -- Abstract: Shape recovery of a 2 mm in diameter shape memory alloy (SMA) wire produced from EB melted NiTi ingot is presented. The results indicate complete shape recovery as high as 9% and a shape recovery higher than 9% for a pre-strain between 10 and 15%. These excellent results are attributed to the high purity of starting ingot with carbon content of 0.016 wt%. It was observed no change in reverse martensitic transformation temperature for pre-strain up to 9% and for higher pre-strain there was a 50 °C increase in reverse martensitic transformation peak temperatures indicating some work hardening of the material.

  7. 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.

  8. Temperature Dependence of Near-Infrared CO_2 Line Shapes Measured by Cavity Ring-Down Spectroscopy

    Science.gov (United States)

    Ghysels, Mélanie; Fleisher, Adam J.; Liu, Qingnan; Hodges, Joseph T.

    2017-06-01

    We present high signal-to-noise ratio, mode-by-mode cavity ring-down spectroscopy (CRDS) line shape measurements of air-broadened transitions in the 30013 → 0001 band of ^{12}C^{16}O_2 located near λ = 1.6 μm. Absorption spectra were acquired from (230-290) K with a variable-temperature spectrometer developed in the framework of the NASA Orbiting Carbon Observatory-2 Mission to improve our understanding of carbon dioxide and oxygen line shape parameters. This system comprises a monolithic, thermally stabilized two-mirror, optical resonator exhibiting a mode stability of 200 kHz and a minimum detectable absorption coefficient of 10^{-11} cm^{-1}. Observed spectra were modeled the using the recently recommended Hartmann-Tran line profile (HTP) (and several of its limiting cases) which includes the effects of Dicke narrowing, speed dependent broadening, correlation between velocity- and phase-changing collisions and first-order line mixing effects. At fixed temperature, line shape parameters were determined by constrained multispectrum fitting of spectra acquired over the pressure range (30 - 300) Torr. For each transition considered, analysis of the temperature dependence of the fitted line shape parameters yielded the pressure-broadening temperature exponent and speed dependence parameter, where the latter quantity was found to be in good agreement with theoretical values consistent with the HTP model. Tennyson, et al., Pure Appl. Chem. 86, (2014) 1931

  9. Polymeric Shape-Memory Micro-Patterned Surface for Switching Wettability with Temperature

    Directory of Open Access Journals (Sweden)

    Nuria García-Huete

    2015-09-01

    Full Text Available An innovative method to switch the wettability of a micropatterned polymeric surface by thermally induced shape memory effect is presented. For this purpose, first polycyclooctene (PCO is crosslinked with dycumil peroxide (DCP and its melting temperature, which corresponds with the switching transition temperature (Ttrans, is measured by Dynamic Mechanical Thermal Analysis (DMTA in tension mode. Later, the shape memory behavior of the bulk material is analyzed under different experimental conditions employing a cyclic thermomechanical analysis (TMA. Finally, after creating shape memory micropillars by laser ablation of crosslinked thermo-active polycyclooctene (PCO, shape memory response and associated effect on water contact angle is analyzed. Thus, deformed micropillars cause lower contact angle on the surface from reduced roughness, but the original hydrophobicity is restored by thermally induced recovery of the original surface structure.

  10. High density thermite mixture for shaped charge ordnance disposal

    Directory of Open Access Journals (Sweden)

    Tamer Elshenawy

    2017-10-01

    Full Text Available The effect of thermite mixture based on aluminum and ferric oxides for ammunition neutralization has been studied and tested. Thermochemical calculations have been carried out for different percentage of Al using Chemical Equilibrium Code to expect the highest performance thermite mixture used for shaped charge ordnance disposal. Densities and enthalpy of different formulations have been calculated and demonstrated. The optimized thermite formulation has been prepared experimentally using cold iso-static pressing technique, which exhibited relatively high density and high burning rate thermite mixture. The produced green product compacted powder mixture was tested against small caliber shaped charge bomblet for neutralization. Theoretical and experimental results showed that the prepared thermite mixture containing 33% of aluminum as a fuel with ferric oxide can be successfully used for shaped charge ordnance disposal.

  11. High-temperature borehole instrumentation

    Science.gov (United States)

    Dennis, B. R.; Koczan, S. P.; Stephani, E. L.

    1985-10-01

    A new method of extracting natural heat from the Earth's crust was invented at the Los Alamos National Laboratory in 1970. It uses fluid pressures (hydraulic fracturing) to produce cracks that connect two boreholes drilled into hot rock formations of low initial permeability. Pressurized water is then circulated through this connected underground loop to extract heat from the rock and bring it to the surface. The creation of the fracture reservior began with drilling boreholes deep within the Precambrian basement rock at the Fenton Hill Test Site. Hydraulic fracturing, flow testing, and well-completion operations required unique wellbore measurements using downhole instrumentation systems that would survive the very high borehole temperatures, 320(0)C (610(0)F). These instruments were not available in the oil and gas industrial complex, so the Los Alamos National Laboratory initiated an intense program upgrading existing technology where applicable, subcontracting materials and equipment development to industrial manufactures, and using the Laboratory resources to develop the necessary downhole instruments to meet programmatic schedules.

  12. 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.

  13. 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.

  14. 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

  15. Size and Shape Dependence on Melting Temperature of Gallium Nitride Nanoparticles

    Directory of Open Access Journals (Sweden)

    Paneerselvam Antoniammal

    2012-01-01

    Full Text Available The study of variation of the size and shape effect on the melting property of gallium nitride nanoparticles with their spherical and cylindrical geometrical feature is theoretically explored. A numerical thermodynamical model has been devoted for the study. A comparative investigation is made between the two shapes, at the range of ~3 nm dia. The cylindrical GaN nanoparticles, whose melting point has been reported to decrease with decreasing particle radius, become larger than spherical-shaped nanoparticles. The melting temperature obtained in the present study is in line with the function of radius of curvature.

  16. Shape-controlled high cell-density microcapsules by electrodeposition.

    Science.gov (United States)

    Liu, Zeyang; Takeuchi, Masaru; Nakajima, Masahiro; Hasegawa, Yasuhisa; Huang, Qiang; Fukuda, Toshio

    2016-06-01

    Cell encapsulation within alginate-poly-l-lysine (PLL) microcapsules has been developed to provide a miniaturized three-dimensional (3D) microenvironment with an aqueous core while promoting development of encapsulated cells into high cell-density structures. In this paper, a novel method for fabricating shape-controlled alginate-PLL microcapsules to construct 3D cell structures based on electrodeposition method is provided. Two-dimensional Ca-alginate cell-laden gel membranes were electrodeposited onto a micro-patterned electrode and further detached from the electrode. The PLL was coated onto the gel structures to form alginate-PLL complex as an outer shell and sodium citric solution was utilized to melt the internal alginate to achieve miniaturized 3D microcapsules (sphere, cuboid, and rod shape). By this proposed method, rat liver cells (RLC-18) formed multi-cellular aggregates with high cell-density after cultivation for 2weeks. The use of alginate-poly-l-lysine (PLL) microcapsules has shown great potential in fabricating 3D cell structures with high cell density. Despite their success related to their ability to provide a miniaturized microenvironment with an aqueous core, alginate-PLL microcapsules has drawback such as a limited shape-control ability. Because of the mechanism of Ca-induced alginate gel formation, it is still difficult to precisely control the gelation process to produce alginate-PLL microcapsules with specific shape. The present study provides an electrodeposition-based method to generate shape-controlled microcapsules for 3D cell structures. Sphere, cuboid, and rod shaped microcapsules of RLC-18 cells were produced for long-term culture to obtain desired morphologies of cell aggregates. Copyright © 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  17. Measurement of thermodynamic temperature of high temperature fixed points

    Energy Technology Data Exchange (ETDEWEB)

    Gavrilov, V. R.; Khlevnoy, B. B.; Otryaskin, D. A.; Grigorieva, I. A.; Samoylov, M. L.; Sapritsky, V. I. [All-Russian Research Institute for Optical and Physical Measurements (VNIIOFI), 46 Ozernaya St., Moscow 119361 (Russian Federation)

    2013-09-11

    The paper is devoted to VNIIOFI's measurements of thermodynamic temperature of the high temperature fixed points Co-C, Pt-C and Re-C within the scope of the international project coordinated by the Consultative Committee for Thermometry working group 5 'Radiation Thermometry'. The melting temperatures of the fixed points were measured by a radiance mode radiation thermometer calibrated against a filter radiometer with known irradiance spectral responsivity via a high temperature black body. This paper describes the facility used for the measurements, the results and estimated uncertainties.

  18. Measurement of thermodynamic temperature of high temperature fixed points

    Science.gov (United States)

    Gavrilov, V. R.; Khlevnoy, B. B.; Otryaskin, D. A.; Grigorieva, I. A.; Samoylov, M. L.; Sapritsky, V. I.

    2013-09-01

    The paper is devoted to VNIIOFI's measurements of thermodynamic temperature of the high temperature fixed points Co-C, Pt-C and Re-C within the scope of the international project coordinated by the Consultative Committee for Thermometry working group 5 "Radiation Thermometry". The melting temperatures of the fixed points were measured by a radiance mode radiation thermometer calibrated against a filter radiometer with known irradiance spectral responsivity via a high temperature black body. This paper describes the facility used for the measurements, the results and estimated uncertainties.

  19. (Krauss) at constant high temperatures

    African Journals Online (AJOL)

    A number of opinions are held on the relative importance of the various physical ... optimum as well as extreme temperatures on vital functions such as survival, egg ..... solids on the biology of certain freshwater molluscs. D .Sc. thesis,. Potch.

  20. INVESTIGATION BY NUMERICAL MODELING OF INFLUENCE OF THE SHAPE OF DEFORMING ZONE OF DIE AT WIRE DRAWING OF STEEL HIGH-CARBON WIRE ON TEMPERATURE AND MODE OF DEFORMATION IN WIRE AND DIE

    Directory of Open Access Journals (Sweden)

    Ju. L. Bobarikin

    2010-01-01

    Full Text Available Investigation by numerical modeling of influence of the form of deforming zone of die at drawing of steel highcarbon wire on temperature and strained-deformed state in wire and die is carried out.

  1. Shape evolution of 72,74Kr with temperature in covariant density functional theory

    Science.gov (United States)

    Zhang, Wei; Niu, Yi-Fei

    2017-09-01

    The rich phenomena of deformations in neutron-deficient krypton isotopes, such as shape evolution with neutron number and shape coexistence, have attracted the interest of nuclear physicists for decades. It is interesting to study such shape phenomena using a novel way, e.g. by thermally exciting the nucleus. In this work, we develop the finite temperature covariant density functional theory for axially deformed nuclei with the treatment of pairing correlations by the BCS approach, and apply this approach for the study of shape evolution in 72,74Kr with increasing temperature. For 72Kr, with temperature increasing, the nucleus firstly experiences a relatively quick weakening in oblate deformation at temperature T ∼0.9 MeV, and then changes from oblate to spherical at T ∼2.1 MeV. For 74Kr, its global minimum is at quadrupole deformation β 2 ∼ ‑0.14 and abruptly changes to spherical at T∼ 1.7 MeV. The proton pairing transition occurs at critical temperature 0.6 MeV following the rule T c=0.6Δ p(0), where Δ p(0) is the proton pairing gap at zero temperature. The signatures of the above pairing transition and shape changes can be found in the specific heat curve. The single-particle level evolutions with temperature are presented. Supported by National Natural Science Foundation of China (11105042, 11305161, 11505157), Open Fund of Key Laboratory of Time and Frequency Primary Standards, CAS, and Support from Henan Administration of Foreign Experts Affairs

  2. 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).

  3. Technological Evolution of High Temperature Superconductors

    Science.gov (United States)

    2015-12-01

    TEMPERATURE SUPERCONDUCTORS by Jordan R. White December 2015 Thesis Advisor: Clifford Whitcomb Co-Advisor: Fotis Papoulias THIS PAGE INTENTIONALLY...AND SUBTITLE TECHNOLOGICAL EVOLUTION OF HIGH TEMPERATURE SUPERCONDUCTORS 5. FUNDING NUMBERS 6. AUTHOR(S) Jordan R. White 7. PERFORMING ORGANIZATION...trends. 14. SUBJECT TERMS electric ships, high temperature superconductor , HTS 15. NUMBER OF PAGES 111 16. PRICE CODE 17. SECURITY CLASSIFICATION

  4. Temperature dependence of the magnetization of disc shaped NiO nanoparticles

    DEFF Research Database (Denmark)

    Klausen, Stine Nyborg; Lindgard, P.A.; Lefmann, Kim

    2002-01-01

    We present neutron diffraction data of NiO nanoparticles measuring the total magnetization and the sublattice magnetization at various temperatures. Electron microscopy shows that the particles are disc shaped with average diameter of about 12 nm and a thickness of about 2 nm. The Neel temperature...... as a temperature dependent contribution of a structural peak in contrast to bulk NiO. The two magnetic signals vanish at the same temperature. The data are interpreted on the basis of an extended mean field model on disc shaped NiO particles. This model includes the finite size dependence of the effective field...... (approximate to460 K) is less than for bulk NiO (523 K). The magnetic domain size, as estimated from the width of the neutron diffraction peaks corresponding to the antiferromagnetic reflection is smaller than the particle size estimated from the structural peaks. A ferromagnetic contribution is present...

  5. 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.

  6. The effect of particle shape on mixing in a high shear mixer

    Science.gov (United States)

    Sinnott, Matthew D.; Cleary, Paul W.

    2016-11-01

    Discrete element method modelling is used to study the effect of particle shape on the flow dynamics and mixing in a high shear mixer. The blade generates strong flow over its top surface while compacting and pushing forward particles that are directly in front of the blade. A complex three dimensional flow is established with vertical and radial flow components that are shape dependent and which control the nature of the mixing. Mixing was found to be fast in the azimuthal direction, of intermediate speed in the vertical direction and comparatively slow in the radial mixing. Diffusive mixing is characterised using the granular temperature which shows that the regions of higher granular temperature are larger for round particles than non-round ones leading to stronger diffusive mixing. The spatial distribution of the convective component of mixing is identified using novel calculation of shear strain rate. This size and shape of the high shear region is found to be only slightly sensitive to the particle shape indicating that the convective mixing is relatively independent of shape, except in the middle of the mixer. The blockiness of the particles has the strongest impact on flow and mixing while the mixing has only a weak dependence on the particle aspect ratio.

  7. Transient analysis and burnout of high temperature superconducting current leads

    Science.gov (United States)

    Seol, S. Y.; Hull, J. R.

    The transient behaviour of high-temperature superconductor (HTS) current leads operated between liquid helium and liquid nitrogen temperatures is analysed for burnout conditions upon transition of the HTS into the normal state. Leads composed of HTS only and of HTS sheathed by pure silver or silver alloy are investigated numerically for temperature-dependent properties and analytically for temperature-independent properties. For lower values of shape factor (current density times length), the lead can be operated indefinitely without burnout. At higher values of shape factor, the lead reaches burnout in a finite time. With high current densities, the leads heat adiabatically. For a fixed shape factor, low current densities are desired to achieve long burnout times. To achieve a low helium boil-off rate in the superconducting state without danger of burnout, there is a preferred temperature dependence for thermal conductivity, and silver alloy sheaths are preferred to pure silver sheaths. However, for a given current density, pure silver sheaths take longer to burn out.

  8. Intraoral Temperature Triggered Shape-Memory Effect and Sealing Capability of A Transpolyisoprene-Based Polymer

    Directory of Open Access Journals (Sweden)

    Gakuji Tsukada

    2015-11-01

    Full Text Available In dentistry, pure gutta-percha (trans-1,4-polyisoprene (TPI is widely used as a main component of root canal filling materials. TPI has an interesting shape memory formed through cross-linking, and this characteristic is expected to be very effective for development of novel dental treatments; in particular, modification of the shape recovery temperature to the intraoral temperature (37 °C will enhance the applicability of the shape-memory effect of TPI in root canal filling. In this study, trial test specimens consisting of varying proportions of TPI, cis-polyisoprene, zinc oxide, stearic acid, sulfur and dicumyl peroxide were prepared and the temperature dependence of their shape recovery, recovery stress and relaxation modulus were measured. Additionally, their sealing abilities were tested using glass tubing and a bovine incisor. As the ratio of cross-linking agent in the specimens increased, a decrease in recovery temperature and an increase in recovery stress and recovery speed were observed. In addition, the test specimen containing the highest concentration of cross-linking agent showed superior sealing ability under a thermal stimulus of 37 °C in both sealing ability tests.

  9. Self-constructed tree-shape high thermal conductivity nanosilver networks in epoxy

    Science.gov (United States)

    Pashayi, Kamyar; Fard, Hafez Raeisi; Lai, Fengyuan; Iruvanti, Sushumna; Plawsky, Joel; Borca-Tasciuc, Theodorian

    2014-03-01

    We report the formation of high aspect ratio nanoscale tree-shape silver networks in epoxy, at low temperatures (polyvinylpyrrolidone (PVP) coated nanoparticles, removal of PVP coating from the surface, and sintering of silver nanoparticles in high aspect ratio networked structures. Controlling self-assembly and sintering by carefully designed multistep temperature and time processing leads to κ of our silver nanocomposites that are up to 300% of the present state of the art polymer nanocomposites at similar volume fractions. Our investigation of the κ enhancements enabled by tree-shaped network nanocomposites provides a basis for the development of new polymer nanocomposites for thermal transport and storage applications.We report the formation of high aspect ratio nanoscale tree-shape silver networks in epoxy, at low temperatures (polyvinylpyrrolidone (PVP) coated nanoparticles, removal of PVP coating from the surface, and sintering of silver nanoparticles in high aspect ratio networked structures. Controlling self-assembly and sintering by carefully designed multistep temperature and time processing leads to κ of our silver nanocomposites that are up to 300% of the present state of the art polymer nanocomposites at similar volume fractions. Our investigation of the κ enhancements enabled by tree-shaped network nanocomposites provides a basis for the development of new polymer nanocomposites for thermal transport and storage applications. Electronic supplementary information (ESI) available: Raman spectroscopy of particles with and without PVP coating, the morphology of uncoated particles, the curing time of samples presented in Fig. 2, optical microscopy images studying the effect of processing time and temperature on nanocomposite agglomeration, measurement results of viscosity versus time for pure epoxy and the 20 vol% silver-epoxy nanocomposite, theoretical determination of the agglomeration time, and the DSC curve of pure bulk PVP are presented in the

  10. Pulse width modulation-based temperature tracking for feedback control of a shape memory alloy actuator.

    Science.gov (United States)

    Ayvali, Elif; Desai, Jaydev P

    2014-04-01

    This work presents a temperature-feedback approach to control the radius of curvature of an arc-shaped shape memory alloy (SMA) wire. The nonlinear properties of the SMA such as phase transformation and its dependence on temperature and stress make SMA actuators difficult to control. Tracking a desired trajectory is more challenging than controlling just the position of the SMA actuator since the desired path is continuously changing. Consequently, tracking the desired strain directly or tracking the parameters such as temperature and electrical resistance that are related to strain with a model is a challenging task. Temperature-feedback is an attractive approach when direct measurement of strain is not practical. Pulse width modulation (PWM) is an effective method for SMA actuation and it can be used along with a compensator to control the temperature of the SMA. Using the constitutive model of the SMA, the desired temperature profile can be obtained for a given strain trajectory. A PWM-based nonlinear PID controller with a feed-forward heat transfer model is proposed to use temperature-feedback for tracking a desired temperature trajectory. The proposed controller is used during the heating phase of the SMA actuator. The controller proves to be effective in tracking step-wise and continuous trajectories.

  11. Thermoelastic properties of minerals at high temperature

    Indian Academy of Sciences (India)

    under high temperatures and calculated the second-order elastic constant (Cij ) and bulk modulus. (KT) of the above minerals, in two cases first by taking Anderson–Gruneisen parameter (δT) as temperature-independent and then by treating δT as temperature-dependent parameter. The results obtained when δT is ...

  12. 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...

  13. 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

  14. 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

  15. High-Temperature Test Technology

    Science.gov (United States)

    1987-03-01

    Do any of your facilities have vacuum test capability? YesO No~l If yes, What is the minimum vacuum chamber pressure? What is the maximum allowable...available? YesO N[-- If "yes," please Indicate the following: Vaporizer Superheater Capacity Capacity Max Temperature LH2 LN2 Are gaseous hydrogen...personnel safety? 5. Does the facility have radiant heating capability? YesO NoF- If "yes," please provide the following information: Lamp types Tungsten

  16. Thermodynamics of High Temperature Materials.

    Science.gov (United States)

    1985-03-15

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

  17. 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

  18. Coherent control in room-temperature quantum dot semiconductor optical amplifiers using shaped pulses

    CERN Document Server

    Karni, Ouri; Eisenstein, Gadi; Ivanov, Vitalii; Reithmaier, Johann Peter

    2016-01-01

    We demonstrate the ability to control quantum coherent Rabi-oscillations in a room-temperature quantum dot semiconductor optical amplifier (SOA) by shaping the light pulses that trigger them. The experiments described here show that when the excitation is resonant with the short wavelength slope of the SOA gain spectrum, a linear frequency chirp affects its ability to trigger Rabi-oscillations within the SOA: A negative chirp inhibits Rabi-oscillations whereas a positive chirp can enhance them, relative to the interaction of a transform limited pulse. The experiments are confirmed by a numerical calculation that models the propagation of the experimentally shaped pulses through the SOA.

  19. High temperature skin friction measurement

    Science.gov (United States)

    Tcheng, Ping; Holmes, Harlan K.; Supplee, Frank H., Jr.

    1989-01-01

    Skin friction measurement in the NASA Langley hypersonic propulsion facility is described. The sensor configuration utilized an existing balance, modified to provide thermal isolation and an increased standoff distance. For test run times of about 20 sec and ambient-air cooling of the test section and balance, the modified balance performed satisfactorily, even when it was subjected to acoustic and structural vibration. The balance is an inertially balanced closed-loop servo system where the current to a moving-coil motor needed to restore or null the output from the position sensor is a measure of the force or skin friction tending to displace the moving element. The accuracy of the sensor is directly affected by the position sensor in the feedback loop, in this case a linear-variable differential transformer which has proven to be influenced by temperature gradients.

  20. Computational Investigation of In-Flight Temperature in Shaped Charge Jets and Explosively Formed Penetrators

    Science.gov (United States)

    Sable, Peter; Helminiak, Nathaniel; Harstad, Eric; Gullerud, Arne; Hollenshead, Jeromy; Hertel, Eugene; Sandia National Laboratories Collaboration; Marquette University Collaboration

    2017-06-01

    With the increasing use of hydrocodes in modeling and system design, experimental benchmarking of software has never been more important. While this has been a large area of focus since the inception of computational design, comparisons with temperature data are sparse due to experimental limitations. A novel temperature measurement technique, magnetic diffusion analysis, has enabled the acquisition of in-flight temperature measurements of hyper velocity projectiles. Using this, an AC-14 bare shaped charge and an LX-14 EFP, both with copper linings, were simulated using CTH to benchmark temperature against experimental results. Particular attention was given to the slug temperature profiles after separation, and the effect of varying equation-of-state and strength models. Simulations are in agreement with experimental, attaining better than 2% error between observed shaped charge temperatures. This varied notably depending on the strength model used. Similar observations were made simulating the EFP case, with a minimum 4% deviation. Jet structures compare well with radiographic images and are consistent with ALEGRA simulations previously conducted. Sandia is a multiprogram laboratory operated by Sandia Corporation, a Lockheed Martin Company, for the United States Department of Energy's National Nuclear Security Administration under contract DE-AC04-94AL85000.

  1. Temperature-dependent gain compensation of CsI(Tl) detectors using pulse shape analysis

    Energy Technology Data Exchange (ETDEWEB)

    Silva, Joel; Isaak, Johann; Loeher, Bastian; Savran, Deniz; Wamers, Felix [ExtreMe Matter Institute EMMI and Research Division, GSI Helmholtzzentrum, Darmstadt (Germany); Frankfurt Institute for Advanced Studies FIAS, Frankfurt (Germany); Vencelj, Matjaz [Jozef Stefan Institute, Ljubljana (Slovenia)

    2014-07-01

    The scintillation properties of CsI(Tl) crystals and the gain of photo-sensors such as avalanche photodiodes (APDs) and photo-multipliers (PMs) are temperature dependent. Therefore, for accurate measurements in γ-ray spectroscopy using CsI(Tl) detectors temperature variations have to be precisely monitored. Since the decay time constants in the scintillation process of CsI(Tl) crystals also depend on the temperature, these changes can be compensated by analyzing the pulse shape of detector signals. The method uses the correlation between the gain and the pulse-shape to correct the effect of the temperature. The results of the implementation of this method using CsI(Tl) crystals read out by PMs are presented. It shows to improve that the energy resolution of the detectors in a temperature changing environment ranging from -10 {sup circle} C to 40 {sup circle} C is improved. The suitability of the method using CsI(Tl) read out by APDs was investigated in the same temperature range. First results are also presented.

  2. Shape memory alloy resistance behaviour at high altitude for feedback control

    Science.gov (United States)

    Ng, W. T.; Sedan, M. F.; Abdullah, E. J.; Azrad, S.; Harithuddin, A. S. M.

    2017-12-01

    Many recent aerospace technologies are using smart actuators to reduce the system's complexity and increase its reliability. One such actuator is shape memory alloy (SMA) actuator, which is lightweight, produces high force and large deflection. However, some disadvantages in using SMA actuators have been identified and they include nonlinear response of the strain to input current, hysteresis characteristic that results in inaccurate control and less than optimum system performance, high operating temperatures, slow response and also high requirement of electrical power to obtain the desired actuation forces. It is still unknown if the SMA actuators can perform effectively at high altitude with low surrounding temperature. The work presented here covers the preliminary process of verifying the feasibility of using resistance as feedback control at high altitude for aerospace applications. Temperature and resistance of SMA actuator at high altitude is investigated by conducting an experiment onboard a high altitude balloon. The results from the high altitude experiment indicate that the resistance or voltage drop of the SMA wire is not significantly affected by the low surrounding temperature at high altitude as compared to the temperature of SMA. Resistance feedback control for SMA actuators may be suitable for aerospace applications.

  3. High Temperature Solid State Lithium Battery Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Reliable energy systems with high energy density capable of operating at high temperatures, pressures and radiation levels are needed for certain NASA missions....

  4. Copper Alloy For High-Temperature Uses

    Science.gov (United States)

    Dreshfield, Robert L.; Ellis, David L.; Michal, Gary

    1994-01-01

    Alloy of Cu/8Cr/4Nb (numbers indicate parts by atom percent) improved over older high-temperature copper-based alloys in that it offers enhanced high temperature strength, resistance to creep, and ductility while retaining most of thermal conductivity of pure copper; in addition, alloy does not become embrittled upon exposure to hydrogen at temperatures as high as 705 degrees C. Designed for use in presence of high heat fluxes and active cooling; for example, in heat exchangers in advanced aircraft and spacecraft engines, and other high-temperature applications in which there is need for such material. High conductivity and hardness of alloy exploited in welding electrodes and in high-voltage and high-current switches and other applications in which wear poses design problem.

  5. Lightweight, High-Temperature Radiator Panels Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Lightweight, high-temperature radiators are needed for future, high-efficiency power conversion systems for Nuclear Electric Propulsion (NEP). Creare has developed...

  6. High Temperature Rechargeable Battery Development Project

    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...

  7. Shape-controlled porous nanocarbons for high performance supercapacitors

    KAUST Repository

    Chén, Wěi

    2014-01-01

    Porous activated nanocarbons with well-controlled dimensionality and morphology (i.e. 0D activated carbon nanoparticles, 1D activated carbon nanotubes, and 2D activated carbon nanosheets) were derived successfully from different template-induced polyaniline nanostructures by facile carbonization and activation processes. The obtained nanocarbons show large specific surface areas (1332-2005 m2 g-1), good conductivities, and highly porous nanoscale architectures. The supercapacitors fabricated using the shape-controlled nanocarbons exhibit high specific capacitance, excellent rate capability, and superior long-term cycling stability in both aqueous and ionic liquid electrolytes. More importantly, a very high energy density of 50.5 W h kg-1 with a power density of 17.4 kW kg-1 can be obtained from the activated carbon nanotube based supercapacitors in an ionic liquid electrolyte (with a charge time of ∼10 s), making the shape-controlled nanocarbons promising candidates for high-performance energy storage devices. © 2014 the Partner Organisations.

  8. Shape-Dependent Activity of Ceria for Hydrogen Electro-Oxidation in Reduced-Temperature Solid Oxide Fuel Cells.

    Science.gov (United States)

    Tong, Xiaofeng; Luo, Ting; Meng, Xie; Wu, Hao; Li, Junliang; Liu, Xuejiao; Ji, Xiaona; Wang, Jianqiang; Chen, Chusheng; Zhan, Zhongliang

    2015-11-04

    Single crystalline ceria nanooctahedra, nanocubes, and nanorods are hydrothermally synthesized, colloidally impregnated into the porous La0.9Sr0.1Ga0.8Mg0.2O3-δ (LSGM) scaffolds, and electrochemically evaluated as the anode catalysts for reduced temperature solid oxide fuel cells (SOFCs). Well-defined surface terminations are confirmed by the high-resolution transmission electron microscopy--(111) for nanooctahedra, (100) for nanocubes, and both (110) and (100) for nanorods. Temperature-programmed reduction in H2 shows the highest reducibility for nanorods, followed sequentially by nanocubes and nanooctahedra. Measurements of the anode polarization resistances and the fuel cell power densities reveal different orders of activity of ceria nanocrystals at high and low temperatures for hydrogen electro-oxidation, i.e., nanorods > nanocubes > nanooctahedra at T ≤ 450 °C and nanooctahedra > nanorods > nanocubes at T ≥ 500 °C. Such shape-dependent activities of these ceria nanocrystals have been correlated to their difference in the local structure distortions and thus in the reducibility. These findings will open up a new strategy for design of advanced catalysts for reduced-temperature SOFCs by elaborately engineering the shape of nanocrystals and thus selectively exposing the crystal facets. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. The flavoured BFSS model at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Asano, Yuhma; Filev, Veselin G. [School of Theoretical Physics, Dublin Institute for Advanced Studies,10 Burlington Road, Dublin 4 (Ireland); Kováčik, Samuel [School of Theoretical Physics, Dublin Institute for Advanced Studies,10 Burlington Road, Dublin 4 (Ireland); Faculty of Mathematics, Physics and Informatics,Comenius University Bratislava, Mlynská dolina, Bratislava, 842 48 (Slovakia); O’Connor, Denjoe [School of Theoretical Physics, Dublin Institute for Advanced Studies,10 Burlington Road, Dublin 4 (Ireland)

    2017-01-25

    We study the high-temperature series expansion of the Berkooz-Douglas matrix model, which describes the D0/D4-brane system. At high temperature the model is weakly coupled and we develop the series to second order. We check our results against the high-temperature regime of the bosonic model (without fermions) and find excellent agreement. We track the temperature dependence of the bosonic model and find backreaction of the fundamental fields lifts the zero-temperature adjoint mass degeneracy. In the low-temperature phase the system is well described by a gaussian model with three masses m{sub A}{sup t}=1.964±0.003, m{sub A}{sup l}=2.001±0.003 and m{sub f}=1.463±0.001, the adjoint longitudinal and transverse masses and the mass of the fundamental fields respectively.

  10. Size, shape and temperature dependent surface energy of binary alloy nanoparticles

    Science.gov (United States)

    Jabbareh, Mohammad Amin

    2017-12-01

    Surface energy has an important role in determining the properties of nanoparticles. Even though, extensive research has been done on the surface energy of pure nanoparticles, the surface energy of alloy nanoparticles has not been considered enough. In this work, based on the liquid drop model for surface energy of pure nanoparticles and Butler's equation, a model for size dependent surface energy of alloy nanoparticles has been developed. In addition to size and concentration, the model can describe the effects of shape and temperature on surface energy of alloy nanoparticles. Cu - Ag and Cu - Au systems have been studied as two examples and the results have been compared with other theoretical models and available simulated data. Reasonable agreements between the results were observed. The results show that the decreasing particle size decreases surface energy of alloy nanoparticles but decreasing temperature and shape factor increases the value of surface energy.

  11. Magnetic resonance flow velocity and temperature mapping of a shape memory polymer foam device

    OpenAIRE

    Wilson Thomas S; Herberg Julie L; Gjersing Erica; Small Ward; Maitland Duncan J

    2009-01-01

    Abstract Background Interventional medical devices based on thermally responsive shape memory polymer (SMP) are under development to treat stroke victims. The goals of these catheter-delivered devices include re-establishing blood flow in occluded arteries and preventing aneurysm rupture. Because these devices alter the hemodynamics and dissipate thermal energy during the therapeutic procedure, a first step in the device development process is to investigate fluid velocity and temperature cha...

  12. Application of High Temperature Superconductors to Accelerators

    CERN Document Server

    Ballarino, A

    2000-01-01

    Since the discovery of high temperature superconductivity, a large effort has been made by the scientific community to investigate this field towards a possible application of the new oxide superconductors to different devices like SMES, magnetic bearings, flywheels energy storage, magnetic shielding, transmission cables, fault current limiters, etc. However, all present day large scale applications using superconductivity in accelerator technology are based on conventional materials operating at liquid helium temperatures. Poor mechanical properties, low critical current density and sensitivity to the magnetic field at high temperature are the key parameters whose improvement is essential for a large scale application of high temperature superconductors to such devices. Current leads, used for transferring currents from the power converters, working at room temperature, into the liquid helium environment, where the magnets are operating, represent an immediate application of the emerging technology of high t...

  13. 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...... cathode air cooled 30 cell HTPEM fuel cell stack developed at the Institute of Energy Technology at Aalborg University. This fuel cell stack uses PEMEAS Celtec P-1000 membranes, runs on pure hydrogen in a dead end anode configuration with a purge valve. The cooling of the stack is managed by running...... 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...

  14. High-temperature heat-pump fluids

    Science.gov (United States)

    Bertinat, M. P.

    1988-05-01

    Heat pumps could be immensely useful in many industrial processes, but standard working fluids are unsuitable for the high temperatures involved. The ideal high-temperature heat-pump fluid should have a high (but not too high) critical temperature, a moderate critical pressure ( approximately=5.0 MPa) and a low (but not too low) boiling point. There are many organic fluids that do meet the above thermodynamic criteria The author's list of 250 contained dozens of them including many of the common laboratory solvents such as ethanol, ether and especially acetone. Unfortunately most of them are highly flammable. The ideal work fluid for high-temperature heat pumps will probably always remain elusive and water, despite its drawbacks will continue to be the best choice in most applications

  15. 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.

  16. Strongly Deformed Nuclear Shapes at Ultra-High Spin and Shape Coexistence in Nsim 90 Nuclei

    Science.gov (United States)

    Riley, M. A.; Aguilar, A.; Evans, A. O.; Hartley, D. J.; Lagergren, K.; Ollier, J.; Paul, E. S.; Pipidis, A.; Simpson, J.; Teal, C.; Twin, P. J.; Wang, X.; Appelbe, D. E.; Campbell, D. B.; Carpenter, M. P.; Clark, R. M.; Cromaz, M.; Darby, I. G.; Fallon, P.; Garg, U.; Janssens, R. V. F.; Joss, D. T.; Kondev, F. G.; Lauritsen, T.; Lee, I. Y.; Lister, C. J.; Macchiavelli, A. O.; Nolan, P. J.; Petri, M.; Rigby, S. V.; Thompson, J.; Unsworth, C.; Ward, D.; Zhu, S.; Ragnarsson, I.

    2009-03-01

    The N sim 90 region of the nuclear chart has featured prominently as the spectroscopy of nuclei at extreme spin has progressed. This talk will present recent discoveries from investigations of high spin behavior in the N sim 90 Er, Tm and Yb nuclei utilizing the Gammasphere gamma-ray spectrometer. In particular it will include discussion of the beautiful shape evolution and coexistence observed in these nuclei along with the identification of a remarkable new family of band structures. The latter are very weakly populated rotational sequences with high moment of inertia that bypass the classic terminating configurations near spin 40-50 hbar, marking a return to collectivity that extends discrete gamma -ray spectroscopy to well over 60 hbar. Establishing the nature of the yrast states in these nuclei beyond the oblate band-termination states has been a major goal for the past two decades. Cranking calculations suggest that these new structures most likely represent stable triaxial strongly deformed bands that lie in a valley of favored shell energy in deformation and particle-number space.

  17. INNOVATIVE INSTRUMENTATION AND ANALYSIS OF THE TEMPERATURE MEASUREMENT FOR HIGH TEMPERATURE GASIFICATION

    Energy Technology Data Exchange (ETDEWEB)

    Seong W. Lee

    2005-04-01

    The systematic tests of the gasifier simulator on the ultrasonic vibration application for cleaning method were completed in this reporting period. Within the systematic tests on the ultrasonic vibration application, the ambient temperature and high temperature status condition were tested separately. The sticky dirt on the thermocouple tip was simulated by the cement-covered layer on the thermocouple tip. At the ambient temperature status, four (4) factors were considered as the input factors affecting the response variable of peeling off rate. The input factors include the shape of the cement-covered layer (thickness and length), the ultrasonic vibration output power, and application time. At the high temperature tests, four (4) different environments were considered as the experimental parameters including air flow supply, water and air supply environment, water/air/fine dust particle supply, and air/water/ammonia/fine dust particle supply environment. The factorial design method was used in the experiment design with twelve (12) data sets of readings. Analysis of Variances (ANOVA) was applied to the results from systematic tests. The ANOVA results show that the thickness and length of the cement-covered layer have the significant impact on the peeling off rate of ultrasonic vibration application at the ambient temperature environment. For the high temperature tests, the different environments do not seem to have significant impact on the temperature changes. These results may indicate that the ultrasonic vibration is one of best cleaning methods for the thermocouple tip.

  18. 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.

  19. 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.

  20. 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.

  1. High temperature spectral gamma well logging

    Energy Technology Data Exchange (ETDEWEB)

    Normann, R.A.; Henfling, J.A.

    1997-01-01

    A high temperature spectral gamma tool has been designed and built for use in small-diameter geothermal exploration wells. Several engineering judgments are discussed regarding operating parameters, well model selection, and signal processing. An actual well log at elevated temperatures is given with spectral gamma reading showing repeatability.

  2. High extinction amplitude modulation in ultrashort pulse shaping

    CERN Document Server

    Lin, Yen-Wei

    2016-01-01

    We explored the issues related to the resolution and the modulation extinction when filtering the spectrum of a UV femtosecond laser with a standard ultrashort pulse shaper. We have learned that a higher pulse shaping resolution often requires a larger working beam size or a higher density grating for greater dispersion. However, these approaches also introduce more optical errors and degrade the extinction. In this work, we examined specifics of each component to determine the best configuration of our spectral filtering setup. As a proof-of-concept demonstration, we utilized elements available as standard products and achieved 100 GHz filtering resolution with high extinction at the UV-A wavelength, which is superb in this wavelength range. The high extinction spectral filtering is especially important while modifying a broadband laser for the optical control of molecule's internal state.

  3. Temperature dependent fracture properties of shape memory alloys: novel findings and a comprehensive model.

    Science.gov (United States)

    Maletta, Carmine; Sgambitterra, Emanuele; Niccoli, Fabrizio

    2016-12-21

    Temperature dependent fracture properties of NiTi-based Shape Memory Alloys (SMAs), within the pseudoelastic regime, were analyzed. In particular, the effective Stress Intensity Factor (SIF) was estimated, at different values of the testing temperature, by a fitting of the William's expansion series, based on Digital Image Correlation (DIC) measurements. It was found that temperature plays an important role on SIF and on critical fast fracture conditions. As a consequence, Linear Elastic Fracture Mechanics (LEFM) approaches are not suitable to predict fracture properties of SMAs, as they do not consider the effects of temperature. On the contrary, good agreements between DIC results and the predictions of an ad-hoc analytical model were observed. In fact, the model takes into account the whole thermo mechanical loading condition, including both mechanical load and temperature. Results revealed that crack tip stress-induced transformations do not represent a toughening effect and this is a completely novel result within the SMA community. Furthremore, it was demonstrated that the analytical model can be actually used to define a temperature independent fracture toughness parameter. Therefore, a new approach is proposed, based on the analytical model, where both mechanical load and temperature are considered as loading parameters in SIF computation.

  4. Ocean acidification and temperature increase impact mussel shell shape and thickness: problematic for protection?

    Science.gov (United States)

    Fitzer, Susan C; Vittert, Liberty; Bowman, Adrian; Kamenos, Nicholas A; Phoenix, Vernon R; Cusack, Maggie

    2015-11-01

    Ocean acidification threatens organisms that produce calcium carbonate shells by potentially generating an under-saturated carbonate environment. Resultant reduced calcification and growth, and subsequent dissolution of exoskeletons, would raise concerns over the ability of the shell to provide protection for the marine organism under ocean acidification and increased temperatures. We examined the impact of combined ocean acidification and temperature increase on shell formation of the economically important edible mussel Mytilus edulis. Shell growth and thickness along with a shell thickness index and shape analysis were determined. The ability of M. edulis to produce a functional protective shell after 9 months of experimental culture under ocean acidification and increasing temperatures (380, 550, 750, 1000 μatm pCO 2, and 750, 1000 μatm pCO 2 + 2°C) was assessed. Mussel shells grown under ocean acidification conditions displayed significant reductions in shell aragonite thickness, shell thickness index, and changes to shell shape (750, 1000 μatm pCO 2) compared to those shells grown under ambient conditions (380 μatm pCO 2). Ocean acidification resulted in rounder, flatter mussel shells with thinner aragonite layers likely to be more vulnerable to fracture under changing environments and predation. The changes in shape presented here could present a compensatory mechanism to enhance protection against predators and changing environments under ocean acidification when mussels are unable to grow thicker shells. Here, we present the first assessment of mussel shell shape to determine implications for functional protection under ocean acidification.

  5. Multi-focus beam shaping of high power multimode lasers

    Science.gov (United States)

    Laskin, Alexander; Volpp, Joerg; Laskin, Vadim; Ostrun, Aleksei

    2017-08-01

    Beam shaping of powerful multimode fiber lasers, fiber-coupled solid-state and diode lasers is of great importance for improvements of industrial laser applications. Welding, cladding with millimetre scale working spots benefit from "inverseGauss" intensity profiles; performance of thick metal sheet cutting, deep penetration welding can be enhanced when distributing the laser energy along the optical axis as more efficient usage of laser energy, higher edge quality and reduction of the heat affected zone can be achieved. Building of beam shaping optics for multimode lasers encounters physical limitations due to the low beam spatial coherence of multimode fiber-coupled lasers resulting in big Beam Parameter Products (BPP) or M² values. The laser radiation emerging from a multimode fiber presents a mixture of wavefronts. The fiber end can be considered as a light source which optical properties are intermediate between a Lambertian source and a single mode laser beam. Imaging of the fiber end, using a collimator and a focusing objective, is a robust and widely used beam delivery approach. Beam shaping solutions are suggested in form of optics combining fiber end imaging and geometrical separation of focused spots either perpendicular to or along the optical axis. Thus, energy of high power lasers is distributed among multiple foci. In order to provide reliable operation with multi-kW lasers and avoid damages the optics are designed as refractive elements with smooth optical surfaces. The paper presents descriptions of multi-focus optics as well as examples of intensity profile measurements of beam caustics and application results.

  6. Effects of Shapes of Solute Molecules on Diffusion: A Study of Dependences on Solute Size, Solvent, and Temperature.

    Science.gov (United States)

    Chan, T C; Li, H T; Li, K Y

    2015-12-24

    Diffusivities of basically linear, planar, and spherical solutes at infinite dilution in various solvents are studied to unravel the effects of solute shapes on diffusion. On the basis of the relationship between the reciprocal of diffusivity and the molecular volume of solute molecules with similar shape in a given solvent at constant temperature, the diffusivities of solutes of equal molecular volume but different shapes are evaluated and the effects due to different shapes of two equal-sized solute molecules on diffusion are determined. It is found that the effects are dependent on the size of the solute pairs studied. Evidence of the dependence of the solute-shape effects on solvent properties is also demonstrated and discussed. Here, some new diffusion data of aromatic compounds in methanol at different temperatures are reported. The result for methanol in this study indicates that the effects of solute shape on diffusivity are only weakly dependent on temperature.

  7. Novel High Temperature Strain Gauge Project

    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...

  8. High Temperature Fiberoptic Thermal Imaging System Project

    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...

  9. High Temperature Capacitors for Venus Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — High temperature power electronics have become a vital aspect of future designs for power converters in spacecraft, battle zone electric power, satellite power...

  10. 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...

  11. NASA High Operating Temperature Technology Program Overview

    Science.gov (United States)

    Nguyen, Q. V.; Hunter, G. W.

    2017-11-01

    NASA’s Planetary Science Division has begun the High Operating Temperature Technology (HOTTech) program to address Venus surface technology challenges by investing in new technology development. This presentation reviews this HOTTech program.

  12. 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)

  13. Materials for the scavanging of hydrogen at high temperatures

    Science.gov (United States)

    Shepodd, Timothy J.; Phillip, Bradley L.

    1997-01-01

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

  14. 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.

  15. 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.

  16. Producing Zirconium Diboride Components with Complex, Near-Net Shape Geometries by Aqueous Room-Temperature Injection Molding

    Science.gov (United States)

    Wiesner, Valerie L.; Youngblood, Jeffrey; Trice, Rodney

    2014-01-01

    Room-temperature injection molding is proposed as a novel, low-cost and more energy efficient manufacturing process capable of forming complex-shaped zirconium diboride (ZrB2) parts. This innovative processing method utilized aqueous suspensions with high powder loading and a minimal amount (5 vol.) of water-soluble polyvinylpyrrolidone (PVP), which was used as a viscosity modifier. Rheological characterization was performed to evaluate the room-temperature flow properties of ZrB2-PVP suspensions. ZrB2 specimens were fabricated with high green body strength and were machinable prior to binder removal despite their low polymer content. After binder burnout and pressureless sintering, the bulk density and microstructure of specimens were characterized using Archimedes technique and scanning electron microscopy. X-Ray Diffraction was used to determine the phase compositions present in sintered specimens. Ultimate strength of sintered specimens will be determined using ASTM C1323-10 compressive C-ring test.

  17. High Temperature, High Pressure Devices for Zonal Isolation in Geothermal Wells

    Energy Technology Data Exchange (ETDEWEB)

    Fabian, Paul [Composite Technology Development, Inc, Lafayette, CO (United States)

    2012-03-31

    producers, and to target individual fractures or fracture networks for testing and validating reservoir models. The goal of this program, therefore, was to develop and demonstrate reliable high-temperature high-pressure zonal isolation devices that are compatible with the high-temperature downhole environment anticipated for Enhanced Geothermal Systems. Over the course of this 3 year program, CTD designed and demonstrated a high temperature high pressure zonal isolation device. CTD has utilized its expertise in high-temperature materials, shape memory composites and foams, and deployment mechanisms for spacecraft and oil tools to develop a new class of HTHP zonal isolation devices for use in EGS. Specifically, the objective was to demonstrate the ability to isolate sections of an EGS wellbore to: 1) enable stimulation; and 2) seal off unwanted flow regions in unknown EGS completion schemes and high-temperature (>200°C) environments at temperatures upwards of 300°C. A concept for a high-temperature, high-pressure zonal isolation device was designed for use in creating circulation paths in environments where temperatures are in excess of 300°C and differential pressures of up to 10,000 psi are required to stimulate solid granite. This new zonal isolation device distributes the high-pressure differential through a significant length of high temperature, shape memory polymer composite material. The development of differential pressure is initiated by a thermally triggered actuation of a ‘structural seal’ that fills the cross section of the bore with the shape memory material. After this preliminary seal is made, differential pressure begins to build through the material as the seal forces the flow to pass through pores in the shape memory material. The shape memory material is compressed into place to react the force of the internal

  18. Fuel particles for high temperature reactors; Combustibles a particules pour reacteurs a haute temperature

    Energy Technology Data Exchange (ETDEWEB)

    Pheip, M. [CEA Cadarache (DEN/CAD/DEC/SESC/LIPA), 13 - Saint Paul lez Durance (France). Dept. d' Etudes des Combustibles; Masson, M. [CEA Valrho, Dept. Radiochimie et Procedes, 30 (France); Perrais, Ch. [CEA Cadarache (DEN/DEC/SPUA), 13 - Saint Paul lez Durance (France). Dept. d' Etudes des Combustibles; Pelletier, M. [CEA Cadarache (DEN/DEC/SESC), 13 - Saint Paul lez Durance (France). Dept. d' Etudes des Combustibles

    2007-07-15

    The concept of fuel particles with a millimeter size was born at the end of the 1950's and is the reference concept of high or very high temperature gas-cooled reactors (HTR/VHTR). The specificity of this fuel concerns its fine divided structure, its all-ceramic composition and its micro-confining properties with respect to fission products. These 3 properties when combined together allow the access to high temperatures and to a high level of safety. This article presents: 1 - the general properties of particle fuels; 2 - the fabrication and control of fuel elements: nuclei elaboration processes, vapor deposition coating of nuclei, shaping of fuel elements, quality control of fabrication; 3 - the fuel particles behaviour under irradiation: mechanical and thermal behaviour, behaviour and diffusion of fission products, ruining mode; 4 - the reprocessing of particle fuels: stakes and options, direct storage, separation of constituents, processing of carbonous wastes; 5 - conclusion. (J.S.)

  19. Laser Plasma Coupling for High Temperature Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Kruer, W.

    1999-11-04

    Simple scaling models indicate that quite high radiation temperatures can be achieved in hohlraums driven with the National Ignition Facility. A scaling estimate for the radiation temperature versus pulse duration for different size NIF hohlraums is shown in Figure 1. Note that a radiation temperature of about 650 ev is projected for a so-called scale 1 hohlraum (length 2.6mm, diameter 1.6mm). With such high temperature hohlraums, for example, opacity experiments could be carried out using more relevant high Z materials rather than low Z surrogates. These projections of high temperature hohlraums are uncertain, since the scaling model does not allow for the very strongly-driven laser plasma coupling physics. Lasnex calculations have been carried out to estimate the plasma and irradiation conditions in a scale 1 hohlraum driven by NIF. Linear instability gains as high as exp(100) have been found for stimulated Brillouin scattering, and other laser-driven instabilities are also far above their thresholds. More understanding of the very strongly-driven coupling physics is clearly needed in order to more realistically assess and improve the prospects for high temperature hohlraums. Not surprisingly, this regime has been avoided for inertial fusion applications and so is relatively unexplored.

  20. Electrons and Phonons in High Temperature Superconductors

    Directory of Open Access Journals (Sweden)

    Anu Singh

    2013-01-01

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

  1. 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

  2. Neutron experiments on high-temperature superconductors

    Science.gov (United States)

    Mook, H. A., Jr.

    1989-12-01

    This report details the trip to the ILL to perform neutron scattering research on high-temperature superconductivity. The trip was very successful because of the excellent users' facilities available at the ILL. The data we accumulated were of high quality and will make an impact on our understanding of high-temperature superconductivity. However, we cannot continue to run a research program in this field with the limited beam time available at the ILL. To make substantial progress in this field, we must restart the High Flux Isotope Reactor.

  3. High Temperature, Wireless Seismometer Sensor for Venus

    Science.gov (United States)

    Ponchak, George E.; Scardelletti, Maximilian C.; Taylor, Brandt; Beard, Steve; Meredith, Roger D.; Beheim, Glenn M.; Hunter Gary W.; Kiefer, Walter S.

    2012-01-01

    Space agency mission plans state the need to measure the seismic activity on Venus. Because of the high temperature on Venus (462? C average surface temperature) and the difficulty in placing and wiring multiple sensors using robots, a high temperature, wireless sensor using a wide bandgap semiconductor is an attractive option. This paper presents the description and proof of concept measurements of a high temperature, wireless seismometer sensor for Venus. A variation in inductance of a coil caused by the movement of an aluminum probe held in the coil and attached to a balanced leaf-spring seismometer causes a variation of 700 Hz in the transmitted signal from the oscillator/sensor system at 426? C. This result indicates that the concept may be used on Venus.

  4. SHAPES - Spatial, high-accuracy, position-encoding sensor

    Science.gov (United States)

    Nerheim, Noble M.; Blue, Randel C.

    1992-01-01

    Future space systems will require control sensors capable of real-time measurements of position coordinates of many structural locations. Applications for such a sensor include figure and vibration control, rendezvous and docking, and structure assembly verification. The paper discusses an experimental study of SHAPES (spatial, high-accuracy, position-encoding sensor), a 3D position sensor that provides range and two angular positions of laser-illuminated retroreflector targets that mark the locations to be measured. Simultaneous range measurements to multiple targets by a time-of-flight corelation of short laser pulses are made with a CCD-equipped streak tube. Angular positions are measured with a CCD camera. Position measurements of 24 targets with sub-millimeter range accuracy at a 10 Hz update rate have been demonstrated.

  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. HIGH TEMPERATURE HIGH PRESSURE THERMODYNAMIC MEASUREMENTS FOR COAL MODEL COMPOUNDS

    Energy Technology Data Exchange (ETDEWEB)

    Vinayak N. Kabadi

    1999-02-20

    It is well known that the fluid phase equilibria can be represented by a number of {gamma}-models , but unfortunately most of them do not function well under high temperature. In this calculation, we mainly investigate the performance of UNIQUAC and NRTL models under high temperature, using temperature dependent parameters rather than using the original formulas. the other feature of this calculation is that we try to relate the excess Gibbs energy G{sup E}and enthalpy of mixing H{sup E}simultaneously. In other words, we will use the high temperature and pressure G{sup E} and H{sup E}data to regress the temperature dependant parameters to find out which model and what kind of temperature dependant parameters should be used.

  7. Integrating new indicators of predictors that shape the public's perception of local extreme temperature in China.

    Science.gov (United States)

    Ban, Jie; Huang, Lei; Chen, Chen; Guo, Yuming; He, Mike Z; Li, Tiantian

    2017-02-01

    The public's risk perception of local extreme heat or cold plays a critical role in community health and prevention under climate change. However, there is limited evidence on such issues in China where extreme weather is occurring more frequently due to climate change. Here, a total of 2500 residents were selected using a three-step sampling method and investigated by a questionnaire in two representative cities. We investigated risk perception of extreme heat in Beijing and extreme cold in Harbin in 2013, aiming to examine their possible correlations with multiple epidemiological factors. We found that exposure, vulnerability, and adaptive ability were significant predictors in shaping public risk perceptions of local extreme temperature. In particular, a 1°C increase in daily temperature resulted in an increased odds of perceiving serious extreme heat in Beijing (OR=1.091; 95% CI: 1.032, 1.153), while a 1°C increase in daily temperature resulted in a decreased odds of perceiving serious extreme cold in Harbin (OR=0.965; 95% CI: 0.939, 0.992). Therefore for both extreme heat and cold, frequent local extreme temperature exposure may amplify a stronger communication. Health interventions for extreme temperature should consider exposure, vulnerability, and adaptive ability factors. This will help improve the public's perception of climatic changes and their willingness to balance adaption and mitigation appropriately. Copyright © 2016 Elsevier B.V. All rights reserved.

  8. Automatic 3D inspection metrology for high-temperature objects

    Science.gov (United States)

    Han, Liya; Li, Zhongwei; Zhong, Kai; Yi, Jie; Shi, Yusheng; Cheng, Xu; Zhan, Guomin; Chen, Ran

    2017-06-01

    3D Visual Inspection for high-temperature objects has attracted more and more attention in the industrial and manufacture field. Until now it is still difficult to measure the shape of high-temperature objects due to the following problems: 1) the radiation and heat transfer through the air seriously affect both human and measurement equipment, so the manual measurement is not capable in this situation. 2) Because of the difficulties to handle the surfaces of the hot objects, it is hard to use artificial markers to align different pieces of data. In order to solve these problems, an automatic 3D shape measurement system for high-temperature objects is proposed by combing an industrial robot with a structured blue light 3D scanner. In this system, the route for inspection is planned with the cooled object and then executed automatically with the same object in hot state to avoid artificial operations. The route is carefully planned to reduce the exposure time of the measurement equipment under the high-temperature situation. Then different pieces of data are premapped during the planning procedure. In the executing procedure, they can be aligned accurately thanks to the good repeatability of the industrial robot. Finally, different pieces of data are merged without artificial markers and the results are better than methods with traditional hand-eye calibration. Experiments verify that the proposed system can conduct the inspection of forging parts under the temperature of 900°C and the alignment precision is 0.0013rad and 0.28mm.

  9. Low Temperature Heating and High Temperature Cooling in Buildings

    DEFF Research Database (Denmark)

    Kazanci, Ongun Berk

    , a single-family house designed for plus-energy targets and equipped with a radiant water-based floor heating and cooling system was studied by means of full-scale measurements, dynamic building simulations and thermodynamic evaluation tools. Thermal indoor environment and energy performance of the house......A heating and cooling system could be divided into three parts: terminal units (emission system), distribution system, and heating and cooling plant (generation system). The choice of terminal unit directly affects the energy performance, and the indoor environment in that space. Therefore......, 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...

  10. Temperature-induced martensite in magnetic shape memory Fe{sub 2}MnGa observed by photoemission electron microscopy

    Energy Technology Data Exchange (ETDEWEB)

    Jenkins, Catherine; Scholl, Andreas; Kainuma, R.; Elmers, Hans-Joachim; Omori, Toshihiro

    2012-01-18

    The magnetic domain structure in single crystals of a Heusler shape memory compound near the composition Fe{sub 2}MnGa was observed during phase transition by photoelectron emission microscopy at Beamline 11.0.1.1 of the Advanced Light Source. The behavior is comparable with recent observations of an adaptive martensite phase in prototype Ni{sub 2}MnGa, although the pinning in the recent work is an epitaxial interface and in this work the e ective pinning plane is a boundary between martensitic variants that transform in a self-accommodating way from the single crystal austenite phase present at high temperatures. Temperature dependent observations of the twinning structure give information as to the coupling behavior between the magnetism and the structural evolution.

  11. Magnetic resonance flow velocity and temperature mapping of a shape memory polymer foam device.

    Science.gov (United States)

    Small, Ward; Gjersing, Erica; Herberg, Julie L; Wilson, Thomas S; Maitland, Duncan J

    2009-12-31

    Interventional medical devices based on thermally responsive shape memory polymer (SMP) are under development to treat stroke victims. The goals of these catheter-delivered devices include re-establishing blood flow in occluded arteries and preventing aneurysm rupture. Because these devices alter the hemodynamics and dissipate thermal energy during the therapeutic procedure, a first step in the device development process is to investigate fluid velocity and temperature changes following device deployment. A laser-heated SMP foam device was deployed in a simplified in vitro vascular model. Magnetic resonance imaging (MRI) techniques were used to assess the fluid dynamics and thermal changes associated with device deployment. Spatial maps of the steady-state fluid velocity and temperature change inside and outside the laser-heated SMP foam device were acquired. Though non-physiological conditions were used in this initial study, the utility of MRI in the development of a thermally-activated SMP foam device has been demonstrated.

  12. Magnetic Resonance Flow Velocity and Temperature Mapping of a Shape Memory Polymer Foam Device

    Energy Technology Data Exchange (ETDEWEB)

    Small IV, W; Gjersing, E; Herberg, J L; Wilson, T S; Maitland, D J

    2008-10-29

    Interventional medical devices based on thermally responsive shape memory polymer (SMP) are under development to treat stroke victims. The goals of these catheter-delivered devices include re-establishing blood flow in occluded arteries and preventing aneurysm rupture. Because these devices alter the hemodynamics and dissipate thermal energy during the therapeutic procedure, a first step in the device development process is to investigate fluid velocity and temperature changes following device deployment. A laser-heated SMP foam device was deployed in a simplified in vitro vascular model. Magnetic resonance imaging (MRI) techniques were used to assess the fluid dynamics and thermal changes associated with device deployment. Spatial maps of the steady-state fluid velocity and temperature change inside and outside the laser-heated SMP foam device were acquired. Though non-physiological conditions were used in this initial study, the utility of MRI in the development of a thermally-activated SMP foam device has been demonstrated.

  13. A phenomenological formulation for the shape/temperature memory effect in amorphous polymers with multi-stress components

    Science.gov (United States)

    Lu, Haibao; Wang, Xiaodong; Yu, Kai; Huang, Wei Min; Yao, Yongtao; Leng, Jinsong

    2017-09-01

    By means of combining the influence of temperature and strain rate, and based on the cooperative Eyring model, a phenomenological formulation for the shape memory effect and temperature memory effect of an amorphous shape memory polymer (SMP) is proposed. The internal stress and stored mechanical energy are correlated to shape/temperature memory behaviours below and above the glass transition temperature. The working mechanism and fundamentals for the chemo-responsive shape memory behaviour in SMPs are further investigated in terms of the activation enthalpy parameter for inductive depression. Simulation using the proposed model is compared with the experimental results reported in the literature. Predictions are also made using the proposed model. This phenomenological framework is expected to provide a powerful tool for investigating the underlying thermomechanics that originate in the movement of cooperative segments and segmental relaxations in SMPs.

  14. 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.

  15. Stability projections for high temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Laquer, H.L.; Edeskuty, F.J.; Hassenzahl, W.V.; Wipf, S.L.

    1989-03-01

    The stability of the new high temperature superconducting oxides has been analyzed, using the methodology developed over the last 25 years for conventional Type II superconductors. The results are presented in graphical form for the temperature range from 4 to 100 K. For a 90 K superconductor the first flux jump field peaks above 7 T at 60 K, ( and for a 120 k superconductor it peaks above 12 T at 75 K). The maximum adiabatically stable thickness increases dramatically. The linear dimension of the minimum propagating zone increases by a factor of 3 to 5, and the quench propagation velocity drops by 4 orders of magnitude. The high temperature superconducting materials will, therefore, have much higher stability than conventional Type II superconductors; their high flux jump fields will make ultra-fine multifilamentary conductors unnecessary and improve the outlook for tape conductors; the energy to create a propagating zone is increased; however, methods of coil protection will have to be modified.

  16. 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...

  17. Influence of Layer Thickness, Raster Angle, Deformation Temperature and Recovery Temperature on the Shape-Memory Effect of 3D-Printed Polylactic Acid Samples.

    Science.gov (United States)

    Wu, Wenzheng; Ye, Wenli; Wu, Zichao; Geng, Peng; Wang, Yulei; Zhao, Ji

    2017-08-19

    The success of the 3D-printing process depends upon the proper selection of process parameters. However, the majority of current related studies focus on the influence of process parameters on the mechanical properties of the parts. The influence of process parameters on the shape-memory effect has been little studied. This study used the orthogonal experimental design method to evaluate the influence of the layer thickness H, raster angle θ, deformation temperature Td and recovery temperature Tr on the shape-recovery ratio Rr and maximum shape-recovery rate Vm of 3D-printed polylactic acid (PLA). The order and contribution of every experimental factor on the target index were determined by range analysis and ANOVA, respectively. The experimental results indicated that the recovery temperature exerted the greatest effect with a variance ratio of 416.10, whereas the layer thickness exerted the smallest effect on the shape-recovery ratio with a variance ratio of 4.902. The recovery temperature exerted the most significant effect on the maximum shape-recovery rate with the highest variance ratio of 1049.50, whereas the raster angle exerted the minimum effect with a variance ratio of 27.163. The results showed that the shape-memory effect of 3D-printed PLA parts depended strongly on recovery temperature, and depended more weakly on the deformation temperature and 3D-printing parameters.

  18. Temperature measurements of high power LEDs

    Science.gov (United States)

    Badalan (Draghici), Niculina; Svasta, Paul; Drumea, Andrei

    2016-12-01

    Measurement of a LED junction temperature is very important in designing a LED lighting system. Depending on the junction temperature we will be able to determine the type of cooling system and the size of the lighting system. There are several indirect methods for junction temperature measurement. The method used in this paper is based on the thermal resistance model. The aim of this study is to identify the best device that would allow measuring the solder point temperature and the temperature on the lens of power LEDs. For this purpose four devices for measuring temperature on a high-power LED are presented and compared according to the acquired measurements: an infrared thermal camera from FLIR Systems, a multimeter with K type thermocouple (Velleman DVM4200), an infrared-spot based noncontact thermometer (Raynger ST) and a measurement system based on a digital temperature sensor (DS1821 type) connected to a PC. The measurements were conducted on an 18W COB (chip-on-board) LED. The measurement points are the supply terminals and the lens of the LED.

  19. Fiber Bragg Grating Filter High Temperature Sensors

    Science.gov (United States)

    Lyons, Donald R.; Brass, Eric D.; Pencil, Eric (Technical Monitor)

    2001-01-01

    We present a scaled-down method for determining high temperatures using fiber-based Bragg gratings. Bragg gratings are distributed along the length of the optical fiber, and have high reflectivities whenever the optical wavelength is twice the grating spacing. These spatially distinct Bragg regions (located in the core of a fiber) are sensitive to local temperature changes. Since these fibers are silica-based they are easily affected by localized changes in temperature, which results in changes to both the grating spacing and the wavelength reflectivity. We exploit the shift in wavelength reflectivity to measure the change in the local temperature. Note that the Bragg region (sensing area) is some distance away from where the temperature is being measured. This is done so that we can measure temperatures that are much higher than the damage threshold of the fiber. We do this by affixing the fiber with the Bragg sensor to a material with a well-known coefficient of thermal expansion, and model the heat gradient from the region of interest to the actual sensor. The research described in this paper will culminate in a working device as well as be the second portion of a publication pending submission to Optics Letters.

  20. 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

  1. 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...

  2. High temperature reactors for cogeneration applications

    Energy Technology Data Exchange (ETDEWEB)

    Verfondern, Karl [Forschungszentrum Juelich (Germany). IEK-6; Allelein, Hans-Josef [Forschungszentrum Juelich (Germany). IEK-6; RWTH Aachen (Germany). Lehrstuhl fuer Reaktorsicherheit und -technik (LRST)

    2016-05-15

    There is a large potential for nuclear energy also in the non-electric heat market. Many industrial sectors have a high demand for process heat and steam at various levels of temperature and pressure to be provided for desalination of seawater, district heating, or chemical processes. The future generation of nuclear plants will be capable to enter the wide field of cogeneration of heat and power (CHP), to reduce waste heat and to increase efficiency. This requires an adjustment to multiple needs of the customers in terms of size and application. All Generation-IV concepts proposed are designed for coolant outlet temperatures above 500 C, which allow applications in the low and medium temperature range. A VHTR would even be able to cover the whole temperature range up to approx. 1 000 C.

  3. On-wafer high temperature characterization system

    Science.gov (United States)

    Teodorescu, L.; ǎghici, F., Dr; Rusu, I.; Brezeanu, G.

    2016-12-01

    In this work a on-wafer high temperature characterization system for wide bandgap semiconductor devices and circuits has been designed, implemented and tested. The proposed system can perform the wafer temperature adjustment in a large domain, from the room temperature up to 3000C with a resolution better than +/-0.50C. In order to obtain both low-noise measurements and low EMI, the heating element of the wafer chuck is supplied in two ways: one is from a DC linear power supply connected to the mains electricity, another one is from a second DC unit powered by batteries. An original temperature control algorithm, different from classical PID, is used to modify the power applied to the chuck.

  4. High Temperature Mechanisms for Venus Exploration

    Science.gov (United States)

    Ji, Jerri; Narine, Roop; Kumar, Nishant; Singh, Sase; Gorevan, Steven

    Future Venus missions, including New Frontiers Venus In-Situ Explorer and three Flagship Missions - Venus Geophysical Network, Venus Mobile Explorer and Venus Surface Sample Return all focus on searching for evidence of past climate change both on the surface and in the atmospheric composition as well as in the interior dynamics of the planet. In order to achieve these goals and objectives, many key technologies need to be developed for the Venus extreme environment. These key technologies include sample acquisition systems and other high-temperature mechanisms and mobility systems capable of extended operation when directly exposed to the Venus surface or lower atmosphere environment. Honeybee Robotics has developed two types of high temperature motors, the materials and components in both motors were selected based on the requirement to survive temperatures above a minimum of 460° C, at earth atmosphere. The prototype Switched Reluctance Motor (SRM) has been operated non-continuously for over 20 hours at Venus-like conditions (460° C temperature, mostly CO2 gas environment) and it remains functional. A drilling system, actuated by two SRMs was tested in Venus-like conditions, 460° C temperature and mostly CO2 gas environment, for more than 15 hours. The drill successfully completed three tests by drilling into chalk up to 6 inches deep in each test. A first generation Brushless DC (BLDC) Motor and high temperature resolver were also tested and the feasibility of the designs was demonstrated by the extended operation of both devices under Venus-like condition. Further development of the BLDC motor and resolver continues and these devices will, ultimately, be integrated into the development of a high temperature sample acquisition scoop and high temperature joint (awarded SBIR Phase II in October, 2007). Both the SR and BLDC motors will undergo extensive testing at Venus temperature and pressure (TRL6) and are expected to be mission ready before the next New

  5. High Summer Temperatures and Mortality in Estonia.

    Directory of Open Access Journals (Sweden)

    Daniel Oudin Åström

    Full Text Available On-going climate change is predicted to result in a growing number of extreme weather events-such as heat waves-throughout Europe. The effect of high temperatures and heat waves are already having an important impact on public health in terms of increased mortality, but studies from an Estonian setting are almost entirely missing. We investigated mortality in relation to high summer temperatures and the time course of mortality in a coastal and inland region of Estonia.We collected daily mortality data and daily maximum temperature for a coastal and an inland region of Estonia. We applied a distributed lag non-linear model to investigate heat related mortality and the time course of mortality in Estonia.We found an immediate increase in mortality associated with temperatures exceeding the 75th percentile of summer maximum temperatures, corresponding to approximately 23°C. This increase lasted for a couple of days in both regions. The total effect of elevated temperatures was not lessened by significant mortality displacement.We observed significantly increased mortality in Estonia, both on a country level as well as for a coastal region and an inland region with a more continental climate. Heat related mortality was higher in the inland region as compared to the coastal region, however, no statistically significant differences were observed. The lower risks in coastal areas could be due to lower maximum temperatures and cooling effects of the sea, but also better socioeconomic condition. Our results suggest that region specific estimates of the impacts of temperature extremes on mortality are needed.

  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. High Summer Temperatures and Mortality in Estonia.

    Science.gov (United States)

    Oudin Åström, Daniel; Åström, Christofer; Rekker, Kaidi; Indermitte, Ene; Orru, Hans

    2016-01-01

    On-going climate change is predicted to result in a growing number of extreme weather events-such as heat waves-throughout Europe. The effect of high temperatures and heat waves are already having an important impact on public health in terms of increased mortality, but studies from an Estonian setting are almost entirely missing. We investigated mortality in relation to high summer temperatures and the time course of mortality in a coastal and inland region of Estonia. We collected daily mortality data and daily maximum temperature for a coastal and an inland region of Estonia. We applied a distributed lag non-linear model to investigate heat related mortality and the time course of mortality in Estonia. We found an immediate increase in mortality associated with temperatures exceeding the 75th percentile of summer maximum temperatures, corresponding to approximately 23°C. This increase lasted for a couple of days in both regions. The total effect of elevated temperatures was not lessened by significant mortality displacement. We observed significantly increased mortality in Estonia, both on a country level as well as for a coastal region and an inland region with a more continental climate. Heat related mortality was higher in the inland region as compared to the coastal region, however, no statistically significant differences were observed. The lower risks in coastal areas could be due to lower maximum temperatures and cooling effects of the sea, but also better socioeconomic condition. Our results suggest that region specific estimates of the impacts of temperature extremes on mortality are needed.

  8. High-resolution field shaping utilizing a masked multileaf collimator.

    Science.gov (United States)

    Williams, P C; Cooper, P

    2000-08-01

    Multileaf collimators (MLCs) have become an important tool in the modern radiotherapy department. However, the current limit of resolution (1 cm at isocentre) can be too coarse for acceptable shielding of all fields. A number of mini- and micro-MLCs have been developed, with thinner leaves to achieve approved resolution. Currently however, such devices are limited to modest field sizes and stereotactic applications. This paper proposes a new method of high-resolution beam collimation by use of a tertiary grid collimator situated below the conventional MLC. The width of each slit in the grid is a submultiple of the MLC width. A composite shaped field is thus built up from a series of subfields, with the main MLC defining the length of each strip within each subfield. Presented here are initial findings using a prototype device. The beam uniformity achievable with such a device was examined by measuring transmission profiles through the grid using a diode. Profiles thus measured were then copied and superposed to generate composite beams, from which the uniformity achievable could be assessed. With the average dose across the profile normalized to 100%, hot spots up to 5.0% and troughs of 3% were identified for a composite beam of 2 x 5.0 mm grids, as measured at Dmax for a 6 MV beam. For a beam composed from 4 x 2.5 mm grids, the maximum across the profile was 3.0% above the average, and the minimum 2.5% below. Actual composite profiles were also formed using the integrating properties of film, with the subfield indexing performed using an engineering positioning stage. The beam uniformity for these fields compared well with that achieved in theory using the diode measurements. Finally sine wave patterns were generated to demonstrate the potential improvements in field shaping and conformity using this device as opposed to the conventional MLC alone. The scalloping effect on the field edge commonly seen on MLC fields was appreciably reduced by use of 2 x 5.0 mm

  9. Gravimeter using high-temperature superconductor bearing.

    Energy Technology Data Exchange (ETDEWEB)

    Hull, J. R.

    1998-09-11

    We have developed a sensitive gravimeter concept that uses an extremely low-friction bearing based on a permanent magnet (PM) levitated over a high-temperature superconductor (HTS). A mass is attached to the PM by means of a cantilevered beam, and the combination of PM and HTS forms a bearing platform that has low resistance to rotational motion but high resistance to horizontal, vertical, or tilting motion. The combination acts as a low-loss torsional pendulum that can be operated in any orientation. Gravity acts on the cantilevered beam and attached mass, accelerating them. Variations in gravity can be detected by time-of-flight acceleration, or by a control coil or electrode that would keep the mass stationary. Calculations suggest that the HTS gravimeter would be as sensitive as present-day superconducting gravimeters that need cooling to liquid helium temperatures, but the HTS gravimeter needs cooling only to liquid nitrogen temperatures.

  10. High Accuracy, Miniature Pressure Sensor for Very High Temperatures Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SiWave proposes to develop a compact, low-cost MEMS-based pressure sensor for very high temperatures and low pressures in hypersonic wind tunnels. Most currently...

  11. Research at Very High Pressures and High Temperatures

    Science.gov (United States)

    Bundy, Francis P.

    1977-01-01

    Reviews research and apparatus utilized in the study of the states and characteristics of materials at very high temperatures and pressures. Includes three examples of the research being conducted. (SL)

  12. Effect of the Network Structure and Programming Temperature on the Shape-Memory Response of Thiol-Epoxy “Click” Systems

    Directory of Open Access Journals (Sweden)

    Alberto Belmonte

    2015-10-01

    Full Text Available This paper presents a new methodology to develop “thiol-epoxy” shape-memory polymers (SMPs with enhanced mechanical properties in a simple and efficient manner via “click” chemistry by using thermal latent initiators. The shape-memory response (SMR, defined by the mechanical capabilities of the SMP (high ultimate strength and strain, the shape-fixation and the recovery of the original shape (shape-recovery, was analyzed on thiol-epoxy systems by varying the network structure and programming temperature. The glass transition temperature (Tg and crosslinking density were modified using 3- or 4- functional thiol curing agents and different amounts of a rigid triglycidyl isocyanurate compound. The relationship between the thermo-mechanical properties, network structure and the SMR was evidenced by means of qualitative and quantitative analysis. The influence of the programming temperature (Tprog on the SMR was also analyzed in detail. The results demonstrate the possibility of tailoring SMPs with enhanced mechanical capabilities and excellent SMR, and intend to provide a better insight into the relationship between the network structure properties, programming temperature and the SMR of unconstrained (stress-free systems; thus, making it easier to decide between different SMP and to define the operative parameters in the useful life.

  13. Timing matters: the underappreciated role of temperature ramp rate for shape control and reproducibility of quantum dot synthesis

    KAUST Repository

    Baumgardner, William J.

    2012-01-01

    Understanding the coupled kinetic and thermodynamics factors governing colloidal nanocrystals nucleation and growth are critical factors in the predictable and reproducible synthesis of advanced nanomaterials. We show that the temporal temperature profile is decisive in tuning the particle shape from pseudo-spherical to monodisperse cubes. The shape of the nanocrystals was characterized by transmission electron microscopy and X-ray diffraction. We introduce a mechanism for the shape controlled synthesis in the context of temperature-dependent nucleation and growth and provide experimental evidence to support it. © 2013 The Royal Society of Chemistry.

  14. Lightweight High-Temperature Thermal Insulation

    Science.gov (United States)

    Wagner, W. R.; Fasheh, J. I.

    1985-01-01

    Fine Ni/Cr fibers sintered into corrosion-resistant, fireproof batt. Possible applications include stoves, furnaces, safes, fire clothing, draperies in public buildings, wall firebreaks, airplane walls, and jetengine components. New insulation takes advantage of some of same properties of nickel/chromium alloy useful in heating elements in toasters, namely, corrosion and oxidation resistance even at high temperatures.

  15. 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 ...

  16. 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...

  17. High Temperature Resistant Exhaust Valve Spindle

    DEFF Research Database (Denmark)

    Bihlet, Uffe Ditlev

    of the engine, new high temperature alloys are required for a specific engine component, the exhaust valve spindle. Two alloys are used for an exhaust valve spindle; one for the bottom of the spindle, and one for the spindle seat. Being placed in the exhaust gas stream, combustion products such as V2O5 and Na2...

  18. Helium-cooled high temperature reactors

    Energy Technology Data Exchange (ETDEWEB)

    Trauger, D.B.

    1985-01-01

    Experience with several helium cooled reactors has been favorable, and two commercial plants are now operating. Both of these units are of the High Temperature Graphite Gas Cooled concept, one in the United States and the other in the Federal Republic of Germany. The initial helium charge for a reactor of the 1000 MW(e) size is modest, approx.15,000 kg.

  19. Complex performance during exposure to high temperatures.

    Science.gov (United States)

    1969-06-01

    The effects of high temperature on psychomotor performance and physiological function were studied on male pilots (age 30-51) holding a current medical certificate. A total of 41 runs were made at neutral (23.8C (75F), or hot (60.0C (140F), 71.1C (16...

  20. 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 ...

  1. 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 ...

  2. High pressure and high temperature behaviour of ZnO

    Energy Technology Data Exchange (ETDEWEB)

    Thakar, Nilesh A. [K. K. Shah Jarodwala Maninagar Science College, Rambaug, Maninagar, Ahmedabad-380008 (India); Bhatt, Apoorva D. [Department of Physics, Gujarat University, Ahmedabad-380009 (India); Pandya, Tushar C., E-mail: pandyatc@gmail.com [St. Xavier' s College, Navrangpura, Ahmedabad-380009 (India)

    2014-04-24

    The thermodynamic properties with the wurtzite (B4) and rocksalt (B1) phases of ZnO under high pressures and high temperatures have been investigated using Tait's Equation of state (EOS). The effects of pressures and temperatures on thermodynamic properties such as bulk modulus, thermal expansivity and thermal pressure are explored for both two structures. It is found that ZnO material gradually softens with increase of temperature while it hardens with the increment of the pressure. Our predicted results of thermodynamics properties for both the phases of ZnO are in overall agreement with the available data in the literature.

  3. 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.

  4. High temperature superconductors applications in telecommunications

    Energy Technology Data Exchange (ETDEWEB)

    Kumar, A.A.; Li, J.; Zhang, M.F. [Prairie View A& M Univ., Texas (United States)

    1994-12-31

    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{sub c} superconductors.

  5. High Performance Shape Memory Polyurethane Synthesized with High Molecular Weight Polyol as the Soft Segment

    Directory of Open Access Journals (Sweden)

    Manzoor Ahmad

    2012-05-01

    Full Text Available Shape memory polyurethanes (SMPUs are typically synthesized using polyols of low molecular weight (MW~2,000 g/mol as it is believed that the high density of cross-links in these low molecular weight polyols are essential for high mechanical strength and good shape memory effect. In this study, polyethylene glycol (PEG-6000 with MW ~6000 g/mol as the soft segment and diisocyanate as the hard segment were used to synthesize SMPUs, and the results were compared with the SMPUs with polycaprolactone PCL-2000. The study revealed that although the PEG-6000-based SMPUs have lower maximum elongations at break (425% and recovery stresses than those of PCL-based SMPUs, they have much better recovery ratios (up to 98% and shape fixity (up to 95%, hence better shape memory effect. Furthermore, PEG-based SMPUs showed a much shorter actuation time of < 10 s for up to 90% shape recovery compared to typical actuation times of tens of seconds to a few minutes for common SMPUs, demonstrated their great potential for applications in microsystems and other engineering components.

  6. Room temperature magnetocaloric effect in Ni-Mn-In-Cr ferromagnetic shape memory alloy thin films

    Science.gov (United States)

    Akkera, Harish Sharma; Singh, Inderdeep; Kaur, Davinder

    2017-02-01

    The influence of Cr substitution for In on the martensitic phase transformation and magnetocaloric effect (MCE) has been investigated in Ni-Mn-Cr-In ferromagnetic shape memory alloy (FSMA) thin films fabricated by magnetron sputtering. Temperature dependent magnetization (M-T) measurements demonstrated that the martensitic transformation temperatures (TM) monotonously increase with the increase of Cr content due to change in valence electron concentration (e/a) and cell volume. From the study of isothermal magnetization curves (M-H), magnetocaloric effect around the martensitic transformation has been investigated in these FSMA thin films. The magnetic entropy change ∆SM of 7.0 mJ/cm3-K was observed in Ni51.1Mn34.9In9.5Cr4.5 film at 302 K in an applied field of 2 T. Further, the refrigerant capacity (RC) was also calculated for all the films in an applied field of 2 T. These findings indicate that the Cr doped Ni-Mn-In FSMA thin films are potential candidates for room temperature micro-length-scale magnetic refrigeration applications.

  7. Sorbents Remove Oxygen At High Temperatures

    Science.gov (United States)

    Sharma, Pramod K.

    1995-01-01

    Cobalt-exchanged, platinized zeolites 13X and L found conveniently reducible in hot gaseous mixture of hydrogen and nitrogen and thereafter useful as sorbents of trace amounts of oxygen at high temperatures. Aided by catalytic action of platinum, sorbents exhibit rapid oxygen-sorption kinetics and, according to thermodynamic properties of O2/CoO system, capable of lowering level of oxygen in otherwise inert gaseous atmosphere to less than 1 part per trillion in temperature range of 400 to 800 degrees C. Inert atmospheres with these oxygen levels required for processing of certain materials in semiconductor industry.

  8. A review of high-temperature adhesives

    Science.gov (United States)

    St.clair, A. K.; St.clair, T. L.

    1981-01-01

    The development of high temperature adhesives and polyphenylquinoxalines (PPQ) is reported. Thermoplastic polyimides and linear PPQ adhesive are shown to have potential for bonding both metals and composite structures. A nadic terminated addition polyimide adhesive, LARC-13, and an acetylene terminated phenylquinoxaline (ATPQ) were developed. Both of the addition type adhesives are shown to be more readily processable than linear materials but less thermooxidatively stable and more brittle. It is found that the addition type adhesives are able to perform, at elevated temperatures up to 595 C where linear systems fail thermoplastically.

  9. Development of high shrinkage polyethylene terephthalate (PET) shape memory polymer tendons for concrete crack closure

    Science.gov (United States)

    Teall, Oliver; Pilegis, Martins; Sweeney, John; Gough, Tim; Thompson, Glen; Jefferson, Anthony; Lark, Robert; Gardner, Diane

    2017-04-01

    The shrinkage force exerted by restrained shape memory polymers (SMPs) can potentially be used to close cracks in structural concrete. This paper describes the physical processing and experimental work undertaken to develop high shrinkage die-drawn polyethylene terephthalate (PET) SMP tendons for use within a crack closure system. The extrusion and die-drawing procedure used to manufacture a series of PET tendon samples is described. The results from a set of restrained shrinkage tests, undertaken at differing activation temperatures, are also presented along with the mechanical properties of the most promising samples. The stress developed within the tendons is found to be related to the activation temperature, the cross-sectional area and to the draw rate used during manufacture. Comparisons with commercially-available PET strip samples used in previous research are made, demonstrating an increase in restrained shrinkage stress by a factor of two for manufactured PET filament samples.

  10. High temperature dynamic engine seal technology development

    Science.gov (United States)

    Steinetz, Bruce M.; Dellacorte, Christopher; Machinchick, Michael; Mutharasan, Rajakkannu; Du, Guang-Wu; Ko, Frank; Sirocky, Paul J.; Miller, Jeffrey H.

    1992-01-01

    Combined cycle ramjet/scramjet engines being designed for advanced hypersonic vehicles, including the National Aerospace Plane (NASP), require innovative high temperature dynamic seals to seal the sliding interfaces of the articulated engine panels. New seals are required that will operate hot (1200 to 2000 F), seal pressures ranging from 0 to 100 psi, remain flexible to accommodate significant sidewall distortions, and resist abrasion over the engine's operational life. This report reviews the recent high temperature durability screening assessments of a new braided rope seal concept, braided of emerging high temperature materials, that shows promise of meeting many of the seal demands of hypersonic engines. The paper presents durability data for: (1) the fundamental seal building blocks, a range of candidate ceramic fiber tows; and for (2) braided rope seal subelements scrubbed under engine simulated sliding, temperature, and preload conditions. Seal material/architecture attributes and limitations are identified through the investigations performed. The paper summarizes the current seal technology development status and presents areas in which future work will be performed.

  11. High temperature aircraft research furnace facilities

    Science.gov (United States)

    Smith, James E., Jr.; Cashon, John L.

    1992-01-01

    Focus is on the design, fabrication, and development of the High Temperature Aircraft Research Furnace Facilities (HTARFF). The HTARFF was developed to process electrically conductive materials with high melting points in a low gravity environment. The basic principle of operation is to accurately translate a high temperature arc-plasma gas front as it orbits around a cylindrical sample, thereby making it possible to precisely traverse the entire surface of a sample. The furnace utilizes the gas-tungsten-arc-welding (GTAW) process, also commonly referred to as Tungsten-Inert-Gas (TIG). The HTARFF was developed to further research efforts in the areas of directional solidification, float-zone processing, welding in a low-gravity environment, and segregation effects in metals. The furnace is intended for use aboard the NASA-JSC Reduced Gravity Program KC-135A Aircraft.

  12. High temperature sensors for exhaust diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Svenningstorp, Henrik

    2000-07-01

    One of the largest problems that we will have to deal with on this planet this millennium is to stop the pollution of our environment. In many of the ongoing works to reduce toxic emissions, gas sensors capable of enduring rough environments and high temperatures, would be a great tool. The different applications where sensors like this would be useful vary between everything from online measurement in the paper industry and food industry to measurement in the exhaust pipe of a car. In my project we have tested Schottky diodes and MlSiCFET sensor as gas sensors operating at high temperatures. The measurement condition in the exhaust pipe of a car is extremely tough, not only is the temperature high and the different gases quite harmful, there are also a lot of particles that can affect the sensors in an undesirable way. In my project we have been testing Schottky diodes and MlSiCFET sensors based on SiC as high temperature sensors, both in the laboratory with simulated exhaust and after a real engine. In this thesis we conclude that these sensors can work in the hostile environment of an engines exhaust. It is shown that when measuring in a gas mixture with a fixed I below one, where the I-value is controlled by the O{sub 2} concentration, a sensor with a catalytic gate metal as sensitive material respond more to the increased O{sub 2} concentration than the increased HC concentration when varying the two correspondingly. A number of different sensors have been tested in simulated exhaust towards NO{sub x}. It was shown that resistivity changes in the thin gate metal influenced the gas response. Tests have been performed where sensors were a part of a SCR system with promising results concerning NH{sub 3} sensitivity. With a working temperature of 300 deg C there is no contamination of the metal surface.

  13. All fiber-optic ultra-sensitive temperature sensor using few-layer MoS2 coated D-shaped fiber

    Science.gov (United States)

    Mohanraj, J.; Velmurugan, V.; Sathiyan, S.; Sivabalan, S.

    2018-01-01

    We experimentally demonstrate a novel all fiber-optic temperature sensor using Molybdenum disulfide (MoS2) nanosheets coated D-shaped fiber (DSF). The DSF exhibits a strong evanescent field interaction with the MoS2 nanosheets which in turn has good optical absorption that results in very high sensitivity. In addition, a few layer MoS2 exhibit high thermal conductivity and therefore highly suitable for temperature sensing. The proposed all fiber temperature sensor was investigated in the temperature range of 26 °C - 83 °C and achieved a maximum optical output power variation of 7 dB. Further, the experimental results show an ultrahigh sensitivity of 0.1211 dB/∘C, a linear correlation coefficient of 99.6 % and a better precision of 0.04 °C. Therefore, the proposed fiber-optic sensor is capable of measuring dynamic temperatures in a harsh environment.

  14. 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...... to 140 ºC and oxygen pressures up to ~100 bar at room temperature. The GDE cell is successfully tested at 130 ºC by means of direct oxidation of methanol and ethanol, respectively. In the second part of the thesis, the emphasis is put on the ORR in H3PO4 with particular focus on the mass transport...... oxidation of ethanol is in principle a promising concept to supply HTPEM-FCs with a sustainable and on large scale available fuel (ethanol from biomass). However, the intermediate temperature tests in the GDE setup show that even on Pt-based catalysts the reaction rates become first significant...

  15. 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

  16. 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.

  17. Self-Assembled TiO2 Nanotube Arrays with U-Shaped Profile by Controlling Anodization Temperature

    Directory of Open Access Journals (Sweden)

    Jingfei Chen

    2010-01-01

    Full Text Available TiO2 nanotube arrays with uniform diameter from top to bottom were fabricated. The synthesizing approach is based on the investigation of the influence of electrolyte temperature on the tube diameter. We found that the inner diameter of the tubes increased with the electrolyte temperature. Accordingly, we improved the tube profile from the general V shape to U shape by raising the electrolyte temperature gradually. This is a simple and fast approach to fabricate uniform TiO2 nanotubes in diameter. The improved TiO2 nanotube arrays may show better properties and have broad potential applications.

  18. 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

  19. High temperature deformation of silicon steel

    Energy Technology Data Exchange (ETDEWEB)

    Rodriguez-Calvillo, Pablo, E-mail: pablo.rodriguez@ctm.com.es [CTM - Technologic Centre, Materials Technology Area, Manresa, Cataluna (Spain); Department of Materials Science and Metallurgical Engineering, Universidad Politecnica de Cataluna, Barcelona (Spain); Houbaert, Yvan, E-mail: Yvan.Houbaert@UGent.be [Department of Materials Science and Engineering, University of Ghent (Belgium); Petrov, Roumen, E-mail: Roumen.Petrov@ugent.be [Department of Materials Science and Engineering, University of Ghent (Belgium); Kestens, Leo, E-mail: Leo.kestens@ugent.be [Department of Materials Science and Engineering, University of Ghent (Belgium); Colas, Rafael, E-mail: rafael.colas@uanl.edu.mx [Facultad de Ingenieria Mecanica y Electrica, Universidad Autonoma de Nuevo Leon (Mexico); Centro de Innovacion, Investigacion y Desarrollo en Ingenieria y Tecnologia, Universidad Autonoma de Nuevo Leon (Mexico)

    2012-10-15

    The microstructure and texture development during high temperature plane strain compression of 2% in weight silicon steel was studied. The tests were carried out at a constant strain rate of 5 s{sup -1} with reductions of 25, 35 and 75% at temperatures varying from 800 to 1100 Degree-Sign C. The changes in microstructure and texture were studied by means of scanning electron microscopy and electron backscattered diffraction. The microstructure close to the surface of the samples was equiaxed, which is attributed to the shear caused by friction, whereas that at the centre of the specimens was made of a mixture of elongated and fine equiaxed grains, the last ones attributed to the action of dynamic recovery followed by recrystallization. It was found that the volume fraction of these equiaxed grains augmented as reduction and temperature increased; a 0.7 volume fraction was accomplished with a 75% reduction at 1100 Degree-Sign C. The texture of the equiaxed and elongated grains was found to vary with the increase of deformation and temperature, as the {gamma}-fibre tends to disappear and the {alpha}-fibre to increase towards the higher temperature range. -- Highlights: Black-Right-Pointing-Pointer The plastic deformation of a silicon containing steel is studied by plane strain compression. Black-Right-Pointing-Pointer Equiaxed and elongated grains develop in different regions of the sample due to recrystallization. Black-Right-Pointing-Pointer Texture, by EBSD, is revealed to be similar in either type of grains.

  20. 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.

  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. Extreme temperature and oil contamination shape the relative abundance of copepod species in the Arctic

    DEFF Research Database (Denmark)

    Dinh, Khuong Van; Nielsen, Torkel Gissel

    The retreat of sea ice in the Arctic under global warming is predicted to intensify oil exploitation and shipping activities in this region, posing the risk of oil contamination. Knowledge on how Arctic secondary producers deal with the combined effects of global warming, particularly the extreme...... and grazing rate in both species and this pattern was independent of temperatures. Notably, exposure to high pyrene resulted in than 70% of mortality in C. finmarchicus that was two times higher than the mortality observed for C. glacialis. These results suggest that extreme temperature under global warming...... temperature and oil exposure is limited. To address this, we exposed females of two copepods species Calanus glacialis and C. finmarchicus to pyrene at three temperatures: 2, 6 and 10°C. Both species co-exist in the Disko Bay, Greenland, but only C. glacialis is a true Arctic specialist while C. finmarchicus...

  3. Influence of stress concentrator shape and testing temperature on impact bending fracture of 17Mn1Si pipe steel

    Science.gov (United States)

    Panin, S. V.; Vlasov, I. V.; Maruschak, P. O.; Moiseenko, D. D.; Berto, F.; Vinogradov, A.

    2017-12-01

    The influence of the notch shape on the impact fracture of 17Mn1Si steel is investigated at different temperatures, with the focus placed on the low temperature behavior. An approach towards fracture characterization has been suggested based on the description of elastic-plastic deformation of impact loaded specimens on the stage of crack initiation and growth at ambient and lower temperatures. The analysis of the impact loading diagrams and fracture energy values for the 17Mn1Si pipe steel reveals the fracture mechanisms depending on the notch shape. It has been found that the testing temperature reduction plays a decisive role in plastic strain localization followed by dynamic fracture of the specimens with differently shaped notches.

  4. Simulations of magnetic hysteresis loops at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Plumer, M. L.; Whitehead, J. P.; Fal, T. J. [Department of Physics and Physical Oceanography, Memorial University of Newfoundland, St. John' s, Newfoundland and Labrador A1B 3X7 (Canada); Ek, J. van [Western Digital Corporation, San Jose, California 94588 (United States); Mercer, J. I. [Department of Computer Science, Memorial University of Newfoundland, St. John' s, Newfoundland and Labrador A1B 3X7 (Canada)

    2014-09-28

    The kinetic Monte-Carlo algorithm as well as standard micromagnetics are used to simulate MH loops of high anisotropy magnetic recording media at both short and long time scales over a wide range of temperatures relevant to heat-assisted magnetic recording. Microscopic parameters, common to both methods, were determined by fitting to experimental data on single-layer FePt-based media that uses the Magneto-Optic Kerr effect with a slow sweep rate of 700 Oe/s. Saturation moment, uniaxial anisotropy, and exchange constants are given an intrinsic temperature dependence based on published atomistic simulations of FePt grains with an effective Curie temperature of 680 K. Our results show good agreement between micromagnetics and kinetic Monte Carlo results over a wide range of sweep rates. Loops at the slow experimental sweep rates are found to become more square-shaped, with an increasing slope, as temperature increases from 300 K. These effects also occur at higher sweep rates, typical of recording speeds, but are much less pronounced. These results demonstrate the need for accurate determination of intrinsic thermal properties of future recording media as input to micromagnetic models as well as the sensitivity of the switching behavior of thin magnetic films to applied field sweep rates at higher temperatures.

  5. Vapor phase lubrication of high temperature alloys

    Energy Technology Data Exchange (ETDEWEB)

    Hanyaloglu, B.F.; Graham, E.E.; Oreskovic, T.; Hajj, C.G. [Cleveland State Univ., OH (United States)

    1995-06-01

    In a previous study, it was found that when a nickel-based superalloy IN750 was heated to high temperatures, a passive layer of aluminum oxide formed on the surface, preventing vapor phase lubrication. In this study, two nickel-chrome-iron alloys and a nickel-copper alloy were studied for high temperature lubrication to see if these alloys, which contained small amounts of aluminum, would exhibit similar behavior. It was found that under static conditions, all three alloys formed a lubricious nodular coating when exposed to a vapor of aryl phosphate. Under dynamic sliding conditions at 500{degrees}C, these alloys were successfully lubricated with a coefficient of friction of 0.1 and no detectable wear. In order to explain these results, a direct correlation between successful vapor phase lubrication and the composition of the alloys containing aluminum has been proposed. If the ratio of copper/aluminum or iron/aluminum is greater that 100 vapor phase, lubrication will be successful. If the ratio is less than 10, a passive aluminum oxide layer will prevent vapor phase lubrication. By selecting alloys with a high iron or copper content, vapor phase lubrication can provide excellent lubrication at high temperatures. 14 refs., 11 figs., 1 tab.

  6. Medium Deep High Temperature Heat Storage

    Science.gov (United States)

    Bär, Kristian; Rühaak, Wolfram; Schulte, Daniel; Welsch, Bastian; Chauhan, Swarup; Homuth, Sebastian; Sass, Ingo

    2015-04-01

    Heating of buildings requires more than 25 % of the total end energy consumption in Germany. Shallow geothermal systems for indirect use as well as shallow geothermal heat storage systems like aquifer thermal energy storage (ATES) or borehole thermal energy storage (BTES) typically provide low exergy heat. The temperature levels and ranges typically require a coupling with heat pumps. By storing hot water from solar panels or thermal power stations with temperatures of up to 110 °C a medium deep high temperature heat storage (MDHTS) can be operated on relatively high temperature levels of more than 45 °C. Storage depths of 500 m to 1,500 m below surface avoid conflicts with groundwater use for drinking water or other purposes. Permeability is typically also decreasing with greater depth; especially in the crystalline basement therefore conduction becomes the dominant heat transport process. Solar-thermal charging of a MDHTS is a very beneficial option for supplying heat in urban and rural systems. Feasibility and design criteria of different system configurations (depth, distance and number of BHE) are discussed. One system is designed to store and supply heat (300 kW) for an office building. The required boreholes are located in granodioritic bedrock. Resulting from this setup several challenges have to be addressed. The drilling and completion has to be planned carefully under consideration of the geological and tectonical situation at the specific site.

  7. Octupole shapes and shape changes at high spins in the Z approx 58, N approx 88 nuclei

    Energy Technology Data Exchange (ETDEWEB)

    Nazarewicz, W. (Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States) Joint Institute for Heavy Ion Research, Holifield Heavy Ion Research Facility, P.O. Box 2008, Oak Ridge, Tennessee 37831 (United States)); Tabor, S.L. (Department of Physics, Florida State University, Tallahassee, Florida 32306 (United States))

    1992-05-01

    The shapes of rotating Xe, Ba, Ce, Nd, and Sm nuclei (84{le}{ital N}{le}94) are calculated using the cranking model with the Woods-Saxon average potential and pairing. The lightest isotopes of Xe and Ba have nearly spherical ground states, but develop octupole and quadrupole deformations under rotation which remain up to very high spins. The ground states of the heavier isotopes have octupole and quadrupole deformations which persist up to medium spins ({ital I}{approx}12{h bar}). At higher spins, a shape transition is predicted to reflection-symmetric aligned many-quasiparticle configurations.

  8. High temperature superconductors for magnetic suspension applications

    Science.gov (United States)

    Mcmichael, C. K.; Cooley, R. S.; Chen, Q. Y.; Ma, K. B.; Lamb, M. A.; Meng, R. L.; Chu, C. W.; Chu, W. K.

    1994-01-01

    High temperature superconductors (HTS) hold the promise for applications in magnetic levitation bearings, vibration damping, and torque coupling. Traditional magnetic suspension systems require active feedback and vibration controls in which power consumption and low frequency vibration are among the major engineering concerns. HTS materials have been demonstrated to be an enabling approach towards such problems due to their flux trapping properties. In our laboratory at TCSUH, we have been conducting a series of experiments to explore various mechanical applications using HTS. We have constructed a 30 lb. model flywheel levitated by a hybrid superconducting magnetic bearing (HSMB). We are also developing a levitated and vibration-dampled platform for high precision instrumentation. These applications would be ideal for space usages where ambient temperature is adequate for HTS to operate properly under greatly reduced cryogenic requirements. We will give a general overview of these potential applications and discuss the operating principles of the HTS devices we have developed.

  9. 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...... membrane fabrication methods have matured over the last decades, and the deposition of very thin films (1–5 µm) of Pd over porous ceramics or modified porous metal supports is quite common. The H2 permeances and the selectivities achieved at 400–500 °C were in the order of 50–100 Nm3/m/h/bar0.5 and greater...... 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...

  10. 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...

  11. 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

  12. Novel High Temperature Magnetic Bearings for Space Vehicle Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Previous high temperature magnetic bearings employed only electromagnets. The work proposed in this SBIR program seeks to utilize High Temperature Permanent Magnets...

  13. Novel High Temperature Magnetic Bearings for Space Vehicle Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Previous high temperature magnetic bearings employed electromagnets only. The work proposed in this SBIR program seeks to utilize High Temperature Permanent Magnets...

  14. Improved Functional Properties and Efficiencies of Nitinol Wires Under High-Performance Shape Memory Effect (HP-SME)

    Science.gov (United States)

    Casati, R.; Saghafi, F.; Biffi, C. A.; Vedani, M.; Tuissi, A.

    2017-09-01

    Martensitic Ti-rich NiTi intermetallics are broadly used in various cyclic applications as actuators, which exploit the shape memory effect (SME). Recently, a new approach for exploiting austenitic Ni-rich NiTi shape memory alloys as actuators was proposed and named high-performance shape memory effect (HP-SME). HP-SME is based on thermal recovery of de-twinned martensite produced by mechanical loading of the parent phase. The aim of the manuscript consists in evaluating and comparing the fatigue and actuation properties of austenitic HP-SME wires and conventional martensitic SME wires. The effect of the thermomechanical cycling on the actuation response and the changes in the electrical resistivity of both shape memory materials were studied by performing the actuation tests at different stages of the fatigue life. Finally, the changes in the transition temperatures before and after cycling were also investigated by differential calorimetric tests.

  15. Improved Functional Properties and Efficiencies of Nitinol Wires Under High-Performance Shape Memory Effect (HP-SME)

    Science.gov (United States)

    Casati, R.; Saghafi, F.; Biffi, C. A.; Vedani, M.; Tuissi, A.

    2017-10-01

    Martensitic Ti-rich NiTi intermetallics are broadly used in various cyclic applications as actuators, which exploit the shape memory effect (SME). Recently, a new approach for exploiting austenitic Ni-rich NiTi shape memory alloys as actuators was proposed and named high-performance shape memory effect (HP-SME). HP-SME is based on thermal recovery of de-twinned martensite produced by mechanical loading of the parent phase. The aim of the manuscript consists in evaluating and comparing the fatigue and actuation properties of austenitic HP-SME wires and conventional martensitic SME wires. The effect of the thermomechanical cycling on the actuation response and the changes in the electrical resistivity of both shape memory materials were studied by performing the actuation tests at different stages of the fatigue life. Finally, the changes in the transition temperatures before and after cycling were also investigated by differential calorimetric tests.

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

    Indian Academy of Sciences (India)

    Abstract. Polycrystalline powder of BaSnO3 was prepared at 1300 ◦C using a high-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) Å. The synthesized powder was characterized using X-ray diffraction ...

  17. High temperature mechanical properties of iron aluminides

    Directory of Open Access Journals (Sweden)

    Morris, D. G.

    2001-04-01

    Full Text Available Considerable attention has been given to the iron aluminide family of intermetallics over the past years since they offer considerable potential as engineering materials for intermediate to high temperature applications, particularly in cases where extreme oxidation or corrosion resistance is required. Despite efforts at alloy development, however, high temperature strength remains low and creep resistance poor. Reasons for the poor high-temperature strength of iron aluminides will be discussed, based on the ordered crystal structure, the dislocation structure found in the material, and the mechanisms of dislocation pinning operating. Alternative ways of improving high temperature strength by microstructural modification and the inclusion of second phase particles will also be considered.

    Durante los últimos años se ha prestado mucha atención a la familia de intermetálicos Fe-Al, puesto que estos constituyen un considerable potencial como materiales de ingeniería en aplicaciones a temperaturas intermedias o altas, sobre todo en casos donde se necesita alta resistencia a la oxidación o corrosión. A pesar del considerable esfuerzo desarrollado para obtener aleaciones con mejores propiedades, su resistencia mecánica a alta temperatura no es muy elevada. Se discutirán los aspectos que contribuyen a la baja resistencia mecánica a temperatura elevada en función de la estructura de dislocaciones y los mecanismos de anclaje que operan en este intermetálico. Se considerarán, también, maneras alternativas para mejorar la resistencia a temperatura elevada mediante la modificación de la microestructura y la incorporación de partículas de segunda fase.

  18. Fundamental aspects of high-temperature corrosion

    OpenAIRE

    Rapp, Robert

    1993-01-01

    Some recent considerations in three widely different aspects of high-temperature corrosion are summarized: 1) reactions at the metal/scale interface in support of scale growth; 2) mass transfer effects in the control of evaporation of volatile reaction products; and 3) the codeposition of multiple elements for diffusion coatings using halide-activated cementation packs. The climb of misfit edge dislocations from the metal/scale interface can achieve the annihilation of vacancies associated wi...

  19. Thermal fuse for high-temperature batteries

    Science.gov (United States)

    Jungst, Rudolph G.; Armijo, James R.; Frear, Darrel R.

    2000-01-01

    A thermal fuse, preferably for a high-temperature battery, comprising leads and a body therebetween having a melting point between approximately 400.degree. C. and 500.degree. C. The body is preferably an alloy of Ag--Mg, Ag--Sb, Al--Ge, Au--In, Bi--Te, Cd--Sb, Cu--Mg, In--Sb, Mg--Pb, Pb--Pd, Sb--Zn, Sn--Te, or Mg--Al.

  20. High-Temperature Thermoelectric Energy Conversion

    Science.gov (United States)

    Wood, C.

    1987-01-01

    Theory of thermoelectric energy conversion at high temperatures and status of research on conversion materials reviewed in report. Shows highest values of thermoelectric figure of merit, Z, found in semiconductor materials. Semiconductors keep wide choice of elements and compounds. Electrical properties tailored to particular application by impurity doping and control of stoichiometry. Report develops definition of Z useful for comparing materials and uses it to evaluate potentials of different classes of materialsmetals, semiconductors, and insulators.

  1. 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.

  2. High-temperature technological processes: Thermophysical principles

    Science.gov (United States)

    Rykalin, N. N.; Uglov, A. A.; Anishchenko, L. M.

    The book is concerned with the principles of thermodynamics and heat transfer theory underlying high-temperature technological processes. Some characteristics of electromagnetic radiation and heat transfer in solids, liquids, and gases are reviewed, and boundary layer theory, surface phenomena, and phase transitions are examined. The discussion includes an analysis of a number of specific processes, such as treatment by concentrated energy fluxes (electron-beam and laser processing) and plasma machining.

  3. Brittle Materials Design, High Temperature Gas Turbine

    Science.gov (United States)

    1981-03-01

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

  4. High temperature inorganic membranes for separating hydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Fain, D.E.; Roettger, G.E. [Oak Ridge K-25 Site, TN (United States)

    1995-08-01

    Effort has continued to accumulate data on the transport of gases over the temperature range from room temperature to 275{degrees}C with inorganic membranes having a range of pore radii from approximately 0.25 nm to 3 mn. An experimental alumina membrane having an estimated mean pore radius of 0.25 nm has been fabricated and tested. Extensive testing of this membrane indicated that the separation factor for helium and carbon tetrafluoride at 250{degrees}C was 59 and the extrapolated high temperature separation factor was 1,193. For safety reasons, earlier flow measurements concentrated on helium, carbon dioxide, and carbon tetrafluoride. New data have been acquired with hydrogen to verify the agreement with the other gases. During the measurements with hydrogen, it was noted that a considerable amount of moisture was present in the test gas. The source of this moisture and its effect on permeance was examined. Improvements were implemented to the flow test system to minimize the water content of the hydrogen test gas, and subsequent flow measurements have shown excellent results with hydrogen. The extrapolation of separation factors as a function of temperature continues to show promise as a means of using the hard sphere model to determine the pore size of membranes. The temperature dependence of helium transport through membranes appears to be considerably greater than other gases for the smallest pore sizes. The effort to extend temperature dependence to the hard sphere model continues to be delayed, primarily because of a lack of adequate adsorption data.

  5. New fluid for high temperature applications

    Energy Technology Data Exchange (ETDEWEB)

    Riva, M.; Flohr, F. [Solvay Fluor GmbH, Hannover (Germany); Froeba, A.P. [Lehrstuhl fuer Technische Thermodynamik (LTT), Univ. Erlangen (Germany)

    2006-12-15

    As a result of the worldwide increased consumption of energy, energy saving measures come more and more in the focus of commercial acting. Besides the efficiency enhancement of energy consuming systems the utilization of waste heat is an additional possibility of saving energy. Areas where this might be feasible are geothermal power plants, local combined heat and power plants, solar-thermal-systems and high temperature heat pumps (HTHP). All these applications need a transfer fluid which secures the transport of the energy from it's source to the place where it is needed at high temperatures. The paper will start with a description or overview of promising energy sources and their utilization. The thermophysical properties of an azeotropic binary mixture of HFC-365mfc and a per-fluoro-poly-ether (PFPE) which fulfils the requirements on a high temperature working fluid are introduced in the second part of the paper. First results and practical experiences in an ORC process are shown in this context followed by an estimation regarding the saved energy or the improved efficiency respectively for other applications The paper will end with a brief outlook on possible new applications e.g. autarkic systems or immersion cooling of electrical parts. (orig.)

  6. High temperature and pressure alkaline electrolysis

    DEFF Research Database (Denmark)

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

    2013-01-01

    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...... the operational temperature and pressure to produce pressurized hydrogen at high rate (m3 H2·h-1·m-2 cell area) and high electrical efficiency. This work describes an exploratory technical study of the possibility to produce hydrogen and oxygen with a new type of alkaline electrolysis cell at high temperatures...... densities of 1.1 A cm-2 and 2.3 A cm-2 have been measured at a cell voltage of 1.5 V and 1.75 V, respectively, without noble metal catalysts. Electrical efficiencies of almost 99 % at 1.1 A cm-2 and 85 % at 2.3 A cm-2 were obtained....

  7. Differences in oral temperature and body shape in two populations with different propensities for obesity

    DEFF Research Database (Denmark)

    Vozarova, B; Weyer, C; Bogardus, C

    2002-01-01

    Body temperature is a function of heat production and heat dissipation. Substantial interindividual variability has been reported in healthy humans. We hypothesized that Pima Indians, a population with a high prevalence of abdominal obesity, may have a lower surface area relative to volume, that ...

  8. Magnetic resonance flow velocity and temperature mapping of a shape memory polymer foam device

    Directory of Open Access Journals (Sweden)

    Wilson Thomas S

    2009-12-01

    Full Text Available Abstract Background Interventional medical devices based on thermally responsive shape memory polymer (SMP are under development to treat stroke victims. The goals of these catheter-delivered devices include re-establishing blood flow in occluded arteries and preventing aneurysm rupture. Because these devices alter the hemodynamics and dissipate thermal energy during the therapeutic procedure, a first step in the device development process is to investigate fluid velocity and temperature changes following device deployment. Methods A laser-heated SMP foam device was deployed in a simplified in vitro vascular model. Magnetic resonance imaging (MRI techniques were used to assess the fluid dynamics and thermal changes associated with device deployment. Results Spatial maps of the steady-state fluid velocity and temperature change inside and outside the laser-heated SMP foam device were acquired. Conclusions Though non-physiological conditions were used in this initial study, the utility of MRI in the development of a thermally-activated SMP foam device has been demonstrated.

  9. Shape and size of jatropha beans (Jatropha curcas L. during drying at different temperatures

    Directory of Open Access Journals (Sweden)

    Valdiney Cambuy Siqueira

    2013-12-01

    Full Text Available This study was carried out to study the physical properties of the jatropha beans over the drying under six air conditions, based on measurements of roundness, sphericity, volume, superficial area, projected area and surface/volume ratio. Jatropha beans with moisture content around 0.61 (decimal d.b. were subjected to thin-layer drying in oven with forced-air circulation under six temperature conditions (36, 45, 60, 75, 90 and 105 °C and relative humidity of 31.7; 19.6; 9.4; 4.8; 2.6 and 1.5% respectively, until reaching the moisture content of 0.11 ± 0.006 (decimal d. b.. The results showed that the necessary time for jatropha beans to reach the moisture content of 0.11 ± 0.006 (decimal d.b. were 1.5; 2.25; 3.0; 4.75; 6.75 and 12.0 h for the drying temperatures of 105, 90, 75, 60, 45 and 36 °C, respectively; and the reduction in the moisture content as well as the drying conditions promoted changes in the shape and reduced the size of the jatropha beans.

  10. High temperature superconducting digital circuits and subsystems

    Energy Technology Data Exchange (ETDEWEB)

    Martens, J.S.; Pance, A.; Whiteley, S.R.; Char, K.; Johansson, M.F.; Lee, L. [Conductus, Sunnyvale, CA (United States); Hietala, V.M.; Wendt, J.R. [Sandia National Labs., Albuquerque, NM (United States); Hou, S.Y.; Phillips, J. [AT and T Bell Labs., Murray Hill, NJ (United States)

    1993-10-01

    The advances in the fabrication of high temperature superconducting devices have enabled the demonstration of high performance and useful digital circuits and subsystems. The yield and uniformity of the devices is sufficient for circuit fabrication at the medium scale integration (MSI) level with performance not seen before at 77 K. The circuits demonstrated to date include simple gates, counters, analog to digital converters, and shift registers. All of these are mid-sized building blocks for potential applications in commercial and military systems. The processes used for these circuits and blocks will be discussed along with observed performance data.

  11. High-temperature alloys for high-power thermionic systems

    Energy Technology Data Exchange (ETDEWEB)

    Shin, Kwang S.; Jacobson, D.L.; D' cruz, L.; Luo, Anhua; Chen, Bor-Ling.

    1990-08-01

    The need for structural materials with useful strength above 1600 k has stimulated interest in refractory-metal alloys. Tungsten possesses an extreme high modulus of elasticity as well as the highest melting temperature among metals, and hence is being considered as one of the most promising candidate materials for high temperature structural applications such as space nuclear power systems. This report is divided into three chapters covering the following: (1) the processing of tungsten base alloys; (2) the tensile properties of tungsten base alloys; and (3) creep behavior of tungsten base alloys. Separate abstracts were prepared for each chapter. (SC)

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

    Science.gov (United States)

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

    2017-12-01

    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.

  13. Shape memory polymers

    Science.gov (United States)

    Wilson, Thomas S.; Bearinger, Jane P.

    2015-06-09

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxyl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  14. Shape memory polymers

    Energy Technology Data Exchange (ETDEWEB)

    Wilson, Thomas S.; Bearinger, Jane P.

    2017-08-29

    New shape memory polymer compositions, methods for synthesizing new shape memory polymers, and apparatus comprising an actuator and a shape memory polymer wherein the shape memory polymer comprises at least a portion of the actuator. A shape memory polymer comprising a polymer composition which physically forms a network structure wherein the polymer composition has shape-memory behavior and can be formed into a permanent primary shape, re-formed into a stable secondary shape, and controllably actuated to recover the permanent primary shape. Polymers have optimal aliphatic network structures due to minimization of dangling chains by using monomers that are symmetrical and that have matching amine and hydroxl groups providing polymers and polymer foams with clarity, tight (narrow temperature range) single transitions, and high shape recovery and recovery force that are especially useful for implanting in the human body.

  15. High-temperature brushless DC motor controller

    Energy Technology Data Exchange (ETDEWEB)

    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.

  16. Differences in Temperature and Water Chemistry Shape Distinct Diversity Patterns in Thermophilic Microbial Communities.

    Science.gov (United States)

    Chiriac, Cecilia M; Szekeres, Edina; Rudi, Knut; Baricz, Andreea; Hegedus, Adriana; Dragoş, Nicolae; Coman, Cristian

    2017-11-01

    This report describes the biodiversity and ecology of microbial mats developed in thermal gradients (20 to 65°C) in the surroundings of three drillings (Chiraleu [CH], Ciocaia [CI], and Mihai Bravu [MB]) tapping a hyperthermal aquifer in Romania. Using a metabarcoding approach, 16S rRNA genes were sequenced from both DNA and RNA transcripts (cDNA) and compared. The relationships between the microbial diversity and the physicochemical factors were explored. Additionally, the cDNA data were used for in silico functionality predictions, bringing new insights into the functional potential and dynamics of these communities. The results showed that each hot spring determined the formation of distinct microbial communities. In the CH mats (40 to 53°C), the abundance of Cyanobacteria decreased with temperature, opposite to those of Chloroflexi and Proteobacteria Ectothiorhodospira , Oscillatoria , and methanogenic archaea dominated the CI communities (20 to 65°C), while the MB microbial mats (53 to 65°C) were mainly composed of Chloroflexi , Hydrogenophilus , Thermi , and Aquificae Alpha-diversity was negatively correlated with the increase in water temperature, while beta-diversity was shaped in each hot spring by the unique combination of physicochemical parameters, regardless of the type of nucleic acid analyzed (DNA versus cDNA). The rank correlation analysis revealed a unique model that associated environmental data with community composition, consisting in the combined effect of Na + , K + , HCO 3 - , and PO 4 3- concentrations, together with temperature and electrical conductivity. These factors seem to determine the grouping of samples according to location, rather than with the similarities in thermal regimes, showing that other parameters beside temperature are significant drivers of biodiversity. IMPORTANCE Hot spring microbial mats represent a remarkable manifestation of life on Earth and have been intensively studied for decades. Moreover, as hot spring

  17. High Pressure and Temperature Effects in Polymers

    Science.gov (United States)

    Bucknall, David; Arrighi, Valeria; Johnston, Kim; Condie, Iain

    Elastomers are widely exploited as the basis for seals in gas and fluid pipelines. The underlying behaviour of these elastomer at the high pressure, elevated temperatures they experience in operation is poorly understood. Consequently, the duty cycle of these materials is often deliberately limited to a few hours, and in order to prevent failure, production is stopped in order to change the seals in critical joints. The result is significant time lost due to bringing down production to change the seals as well as knock on financial costs. In order to address the fundamental nature of the elastomers at their intended operating conditions, we are studying the gas permeation behaviour of hydrogenated natural butyl rubber (HNBR) and fluorinated elastomers (FKM) at a high pressure and elevated temperature. We have developed a pressure system that permits gas permeation studies at gas pressures of up to 5000 psi and operating temperatures up to 150° C. In this paper, we will discuss the nature of the permeation behaviour at these extreme operating conditions, and how this relates to the changes in the polymer structure. We will also discuss the use of graphene-polymer thin layer coatings to modify the gas permeation behaviour of the elastomers.

  18. Conformal Properties in High Temperature QCD

    CERN Document Server

    Ishikawa, K -I; Nakayama, Yu; Yoshie, T

    2015-01-01

    We investigate the properties of quarks and gluons above the chiral phase transition temperature $T_c,$ using the RG improved gauge action and the Wilson quark action with two degenerate quarks mainly on a $32^3\\times 16$ 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 non-trivial $Z(3)$ center. This is in agreement with our lattice simulation of high temperature QCD. We further observe that the temporal propagator of massless quarks at extremely high temperature $\\beta=100.0 \\, (T \\simeq10^{58} T_c)$ remarkably agrees with the temporal propagator of free quarks with the $Z(3)$ twisted boundary condition for $t/L_t \\geq 0.2$, but differs from that with the $Z(3)$ trivial boundary condition. As we increase the mass of quarks $m_q$, we find that the thermal ensemble continues to be dominated by the $Z(3)$ twisted gauge fi...

  19. 3D Shape Modeling Using High Level Descriptors

    DEFF Research Database (Denmark)

    Andersen, Vedrana

    The goal of this Ph.D. project is to investigate and improve the methods for describing the surface of 3D objects, with focus on modeling geometric texture on surfaces. Surface modeling being a large field of research, the work done during this project concentrated around a few smaller areas...... features like thorns, bark and scales. Presented here is a simple method for easy modeling, transferring and editing that kind of texture. The method is an extension of the height-field texture, but incorporates an additional tilt of the height field. Related to modeling non-heightfield textures, a part...... of my work involved developing feature-aware resizing of models with complex surfaces consisting of underlying shape and a distinctive texture detail. The aim was to deform an object while preserving the shape and size of the features....

  20. Shape-selective catalysis for synthesis of high-value chemicals from aromatics in coal liquids

    Energy Technology Data Exchange (ETDEWEB)

    Song, Chunshan; Schobert, H.H. [Pennsylvania State Univ., University Park, PA (United States)

    1996-12-31

    Liquids derived from coals contain numerous aromatic compounds. Many of the one- to four-ring aromatic and polar compounds can be converted into valuable chemicals. Economic analysis of the viability of liquefaction (and related conversion processes) may well produce a different result if some of the aromatics and phenolics are used for making high-value chemicals and some of the liquids for making high-quality fuels such as thermally stable aviation fuels. To make effective use of aromatics in coal liquids, we are studying shape-selective catalytic conversion of multi-ring compounds. The products of such reactions are intermediates for making value-added chemicals, monomers of advanced polymer materials, or components of advanced jet fuels. Two broad strategic approaches can be used for making chemicals and materials from coals. The first is the indirect approach: conversion of coals to liquids, followed by transformation of compounds in the liquids into value-added products. The second is direct conversion of coals to materials and chemicals. Both approaches are being explored in this laboratory. In this paper, we will give an account of our recent work on (1) shape-selective catalysis which demonstrates that high-value chemicals can be obtained from aromatic compounds by catalytic conversion over certain zeolites; and (2) catalytic graphitization of anthracites, which reveals that using some metal compounds promotes graphitization at lower temperatures and may lead to a more efficient process for making graphites from coals.

  1. High density thermite mixture for shaped charge ordnance disposal

    OpenAIRE

    Elshenawy, Tamer; Soliman, Salah; Hawass, Ahmed

    2017-01-01

    The effect of thermite mixture based on aluminum and ferric oxides for ammunition neutralization has been studied and tested. Thermochemical calculations have been carried out for different percentage of Al using Chemical Equilibrium Code to expect the highest performance thermite mixture used for shaped charge ordnance disposal. Densities and enthalpy of different formulations have been calculated and demonstrated. The optimized thermite formulation has been prepared experimentally using col...

  2. High Temperature Battery for Drilling Applications

    Energy Technology Data Exchange (ETDEWEB)

    Josip Caja

    2009-12-31

    In this project rechargeable cells based on the high temperature electrochemical system Na/beta''-alumina/S(IV) in AlCl3/NaCl were developed for application as an autonomous power source in oil/gas deep drilling wells. The cells operate in the temperature range from 150 C to 250 C. A prototype DD size cell was designed and built based on the results of finite element analysis and vibration testing. The cell consisted of stainless steel case serving as anode compartment with cathode compartment installed in it and a seal closing the cell. Critical element in cell design and fabrication was hermetically sealing the cell. The seal had to be leak tight, thermally and vibration stable and compatible with electrode materials. Cathode compartment was built of beta''-alumina tube which served as an electrolyte, separator and cathode compartment.

  3. 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.

  4. 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.

  5. 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.

  6. Diamond switches for high temperature electronics

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-04-25

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

  7. Electrical Conductivity of Micas at High Temperatures

    Science.gov (United States)

    Watanabe, T.

    2008-12-01

    Electrical conductivity, along with seismic velocity, gives us clues to infer constituent materials and temperatures in the Earth's interior. Dry rocks have been considered to be electrically insulating at crustal temperatures. Observed high conductivity has been ascribed to the existence of fluids. However, Fuji-ta et al. (2007) recently reported that a dry gneiss shows relatively high conductivity (10-4-10-3 S/m) at the temperature of 300-400°C, and that it is strongly anisotropic in conductivity. They suggested that the alignment of biotite grains governs conductivity of the gneiss sample. Electrical properties of rock forming minerals are still poorly understood. We thus have measured electrical properties of biotite single crystals up to 700°C. In order to get a good understanding of conduction mechanisms, measurements have been also made on phlogopite and muscovite, which are common micas with similar crystallographic structures. Thin plates parallel to cleavages (thickness~0.1mm) were prepared from mica single crystals. Electrical impedance was measured by 2-electrode method. The specimen was kept in nitrogen or argon atmosphere. The conductivity measured parallel to cleavages is higher than that measured perpendicular to cleavages by 3-4 orders of magnitude. However, no significant difference in the activation energy of conductivity was observed between two directions. The activation energy of conductivity is ~50 kJ/mol for biotite and ~100 kJ/mol for phlogopite and muscovite. The conductivity of biotite is higher than those of phlogopite and muscovite by several orders of magnitude at the same temperature. The conductivity of biotite parallel to cleavages is ~10-1 S/m at 400°C. The conductivity of biotite increases irreversibly by heating. The irreversible change was not significant below 450°C. Remarkable increase is observed at the temperature of 450-550°C. No significant change was observed in the second heating. Such an increase in conductivity

  8. 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.

  9. 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

  10. Diamond based detectors for high temperature, high radiation environments

    Science.gov (United States)

    Metcalfe, A.; Fern, G. R.; Hobson, P. R.; Smith, D. R.; Lefeuvre, G.; Saenger, R.

    2017-01-01

    Single crystal CVD diamond has many desirable properties as a radiation detector; exceptional radiation hardness and physical hardness, chemical inertness, low Z (close to human tissue, good for dosimetry and transmission mode applications), wide bandgap (high temperature operation with low noise and solar blind), an intrinsic pathway to fast neutron detection through the 12C(n,α)9Be reaction. This combination of radiation hardness, temperature tolerance and ability to detect mixed radiation types with a single sensor makes diamond particularly attractive as a detector material for harsh environments such as nuclear power station monitoring (fission and fusion) and oil well logging. Effective exploitation of these properties requires the development of a metallisation scheme to give contacts that remain stable over extended periods at elevated temperatures (up to 250°C in this instance). Due to the cost of the primary detector material, computational modelling is essential to best utilise the available processing methods for optimising sensor response through geometry and conversion media configurations and to fully interpret experimental data. Monte Carlo simulations of our diamond based sensor have been developed, using MCNP6 and FLUKA2011, assessing the sensor performance in terms of spectral response and overall efficiency as a function of the detector and converter geometry. Sensors with varying metallisation schemes for high temperature operation have been fabricated at Brunel University London and by Micron Semiconductor Limited. These sensors have been tested under a varied set of conditions including irradiation with fast neutrons and alpha particles at high temperatures. The presented study indicates that viable metallisation schemes for high temperature contacts have been successfully developed and the modelling results, supported by preliminary experimental data from partners, indicate that the simulations provide a reasonable representation of

  11. Effects of catalyst height on diamond crystal morphology under high pressure and high temperature

    Science.gov (United States)

    Ya-Dong, Li; Xiao-Peng, Jia; Bing-Min, Yan; Ning, Chen; Chao, Fang; Yong, Li; Hong-An, Ma

    2016-04-01

    The effect of the catalyst height on the morphology of diamond crystal is investigated by means of temperature gradient growth (TGG) under high pressure and high temperature (HPHT) conditions with using a Ni-based catalyst in this article. The experimental results show that the morphology of diamond changes from an octahedral shape to a cub-octahedral shape as the catalyst height rises. Moreover, the finite element method (FEM) is used to simulate the temperature field of the melted catalyst/solvent. The results show that the temperature at the location of the seed diamond continues to decrease with the increase of catalyst height, which is conducive to changing the morphology of diamond. This work provides a new way to change the diamond crystal morphology. Project supported by the National Natural Science Foundation of China (Grant No. 51172089), the Program for New Century Excellent Talents in University, the Natural Science Foundation of Guizhou Provincial Education Department (Grant No. KY[2013]183), and the Collaborative Fund of Science and Technology Office of Guizhou Province, China (Grant No. LH[2015]7232).

  12. SHAPE: Shape Memory for a High Turn-Down Ratio Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Spacecraft designed for missions beyond low earth orbit (LEO) face a difficult thermal control challenge: they are required to reject a high heat load to warm...

  13. Modeling Study of High Pressure and High Temperature Reservoir Fluids

    DEFF Research Database (Denmark)

    Varzandeh, Farhad

    With dwindling easily accessible oil and gas resources, more and more exploration and production activities in the oil industry are driven to technically challenging environments such as unconventional resources and deeper formations. The temperature and pressure can become extremely high, e.g., up...

  14. Robust Joining and Assembly of Ceramic Matrix Composites for High Temperature Applications

    Science.gov (United States)

    Singh, Mrityunjay

    2003-01-01

    Advanced ceramic matrix composites (CMCs) are under active consideration for use in a wide variety of high temperature applications within the aerospace, energy, and nuclear industries. The engineering designs of CMC components require fabrication and manufacturing of large and complex shaped parts of various thicknesses. In many instances, it is more economical to build up complex shapes by joining simple geometrical shapes. Thus, joining and attachment have been recognized as enabling technologies for successful utilization of ceramic components in various demanding applications. In this presentation, various challenges and opportunities in design, fabrication, and testing of high temperature joints in ceramic matrix composites will be presented. A wide variety of ceramic composites, in different shapes and sizes, have been joined using an affordable, robust ceramic joining technology (ARCJoinT). Microstructure and mechanical properties of joints in melt infiltrated and CVI Sic matrix composites will be reported. Various joint design philosophies and design issues in joining of composites will be discussed.

  15. Assessment of high-temperature filtering elements

    Energy Technology Data Exchange (ETDEWEB)

    Monica Lupion; Francisco J. Gutierrez Ortiz; Benito Navarrete; Vicente J. Cortes [University of Seville, Seville (Spain). E.T.S. Ingenieros

    2008-07-01

    A complete experimental campaign has been carried out in a hot gas filtration test facility so as to test several filtering elements and configurations, particularly, three different types of bag filters and one ceramic candle. The facility was designed to operate under a wide range of conditions, thus providing an excellent tool for the investigation of hot gas filtration applications for the advanced electrical power generation industry such as IGCC, PFBC or fuel cell technologies. Relevant parameters for the characterization and optimization of the performance of the filters have been studied for a variety of operation conditions such as filtration velocity, particle concentration, pressure and temperature among others. Pressure drop across the filter, cleaning pulse interval, baseline pressure drop, filtration efficiency and durability of the filter have been investigated for each type considered and dependences on parameters have been established. On top of that, optimal operating conditions and cleaning strategies were determined. The tests results show that bag filters are a suitable alternative for the hot gas filtration due to the better performance and the high efficiency observed, which makes them suitable for industrial applications operating under high temperature high pressure conditions considered within the study (200-370{degree}C and 4-7.5 barg respectively). 7 refs., 7 figs., 10 tabs.

  16. 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...

  17. Pulse Radiolysis at High Temperatures and High Pressures

    DEFF Research Database (Denmark)

    Christensen, H.; Sehested, Knud

    1981-01-01

    A set-up enabling pulse radiolysis measurements at high temperatures (up to 320°C) and high pressures (up to 140 bar) has been constructed in collaboration between Risö National Laboratory and Studsvik Energiteknik. The cell has been used for experiments with aqueous solutions with the purpose.......2 kcal.mol−1) and OH+OH (tentatively 8 kJ·mol−1, 1.9 kcal·mol−1) have been determined. The absorption spectrum of the OH radical has been determined up to temperatures of 200°C. The absorption maximum is found at 230 nm at all temperatures. The reaction between Fe2+ and OH radicals has been studied up...... to a temperature of 220°C. An activation energy of 9 kJ·mol−1 (2.2 kcal·mol−1) has been determined and the spectrum of the transient formed in the reaction has been determined at different temperatures....

  18. High temperature GaAs X-ray detectors

    Science.gov (United States)

    Lioliou, G.; Whitaker, M. D. C.; Barnett, A. M.

    2017-12-01

    Two GaAs p+-i-n+ mesa X-ray photodiodes were characterized for their electrical and photon counting X-ray spectroscopic performance over the temperature range of 100 °C to -20 °C. The devices had 10 μm thick i layers with different diameters: 200 μm (D1) and 400 μm (D2). The electrical characterization included dark current and capacitance measurements at internal electric field strengths of up to 50 kV/cm. The determined properties of the two devices were compared with previously reported results that were made with a view to informing the future development of photon counting X-ray spectrometers for harsh environments, e.g., X-ray fluorescence spectroscopy of planetary surfaces in high temperature environments. The best energy resolution obtained (Full Width at Half Maximum at 5.9 keV) decreased from 2.00 keV at 100 °C to 0.66 keV at -20 °C for the spectrometer with D1, and from 2.71 keV at 100 °C to 0.71 keV at -20 °C for the spectrometer with D2. Dielectric noise was found to be the dominant source of noise in the spectra, apart from at high temperatures and long shaping times, where the main source of photopeak broadening was found to be the white parallel noise.

  19. Materials for the scavenging of hydrogen at high temperatures

    Science.gov (United States)

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

    1997-04-29

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

  20. High temperature behaviour of a zircon ceramic

    Energy Technology Data Exchange (ETDEWEB)

    Carbonneau, X.; Olagnon, C.; Fantozzi, G. [INSA, Villeurbanne (France). GEMMPM; Hamidouche, M. [Lab. Science des Materiaux, Univ. de Setif (Algeria); Torrecillas, R. [Inst. Nacional del Carbon, Oviedo (Spain)

    1997-12-31

    The high temperature properties of a sintered zircon material has been tested up to 1200 C. A significant creep rate is observed, mainly attributed to the presence of glassy phase. The sub-critical crack growth measured in double torsion showed that above 1000 C, the crack velocity is reduced either by stress relaxation or by crack healing. The thermal shock analysis under a heat exchange coefficient of 600 W/m{sup 2}/K showed a regular decrease rather that a sudden fall off of properties. (orig.) 3 refs.

  1. Encapsulation of high temperature molten salts

    Energy Technology Data Exchange (ETDEWEB)

    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.

  2. High Temperature Materials Laboratory third annual report

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-12-01

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

  3. Ceramic Near-Net Shaped Processing Using Highly-Loaded Aqueous Suspensions

    Science.gov (United States)

    Rueschhoff, Lisa

    Ceramic materials offer great advantages over their metal counterparts, due to their lower density, higher hardness and wear resistance, and higher melting temperatures. However, the use of ceramics in applications where their properties would offer tremendous advantages are often limited due to the difficulty of forming them into complex and near-net shaped parts. Methods that have been developed to injection-mold or cast ceramics into more complicated shapes often use significant volume fractions of a carrier (often greater than 35 vol.% polymer), elevated temperature processing, or less-than-environmentally friendly chemicals where a complex chemical synthesis reaction must be timed perfectly for the approach to work. Furthermore, the continuing maturation of additive manufacturing methods requires a new approach for flowing/placing ceramic powders into useful designs. This thesis addresses the limitations of the current ceramic forming approaches by developing highly-stabilized and therefore high solids loading ceramic suspensions, with the requisite rheology for a variety of complex and near-net shaped forming techniques. Silicon nitride was chosen as a material of focus due to its high fracture toughness compared to other ceramic materials. Designing ceramic suspensions that are flowable at room temperature greatly simplifies processing as neither heating nor cooling are required during forming. Highly-loaded suspensions (>40 vol.%) are desired because all formed ceramic bodies have to be sintered to remove pores. Finally, using aqueous-based suspensions reduces any detrimental effect on the environment and tooling. The preparation of highly-loaded suspensions requires the development of a suitable dispersant through which particle-particle interactions are controlled. However, silicon nitride is difficult to stabilize in water due to complex surface and solution chemistry. In this study, aqueous silicon nitride suspensions up to 45 vol.% solids loading were

  4. Bio-Heat Is a Key Environmental Driver Shaping the Microbial Community of Medium-Temperature Daqu.

    Science.gov (United States)

    Xiao, Chen; Lu, Zhen-Ming; Zhang, Xiao-Juan; Wang, Song-Tao; Ao, Ling; Shen, Cai-Hong; Shi, Jin-Song; Xu, Zheng-Hong

    2017-12-01

    "Daqu" is a saccharifying and fermenting agent commonly used in the traditional solid-state fermentation industry (e.g., baijiu and vinegar). The patterns of microbial community succession and flavor formation are highly similar among batches, yet the mechanisms promoting temporal succession in the Daqu microbial ecology remain unclear. Here, we first correlated temporal profiles of microbial community succession with environmental variables (temperature, moisture, and titratable acidity) in medium temperature Daqu (MT-Daqu) throughout fermentation. Temperature dynamics significantly correlated (P bio-heat generated by microbial metabolism (53 to 56°C) within MT-Daqu inhibited the growth of most microbes from day 4 to day 12, while thermotolerant taxa, including Bacillus, unclassified Streptophyta, Weissella, Thermoactinomyces, Thermoascus, and Thermomyces survived or kept on growing. Furthermore, temperature as a major driving force on the shaping of MT-Daqu microbiota was validated. Lowering the fermentation temperature by placing the MT-Daqu in a 37°C incubator resulted in decreased relative abundances of thermotolerant taxa, including Bacillus, Thermoactinomyces, and Thermoascus, in the MT-Daqu microbiota. This study revealed that bio-heat functioned as a primary endogenous driver promoting the formation of functional MT-Daqu microbiota.IMPORTANCE Humans have mastered the Daqu preparation technique of cultivating functional microbiota on starchy grains over thousands of years, and it is well known that the metabolic activity of these microbes is key to the flavor production of Chinese baijiu. The pattern of microbial community succession and flavor formation remains highly similar between batches, yet mechanistic insight into these patterns and into microbial population fidelity to specific environmental conditions remains unclear. Our study revealed that bio-heat was generated within Daqu bricks in the first 4 d of fermentation, concomitant with rapid

  5. 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...

  6. Effects of pre-strain and Nb content on transformation temperatures in Ti-Ni-Nb shape memory alloy

    Energy Technology Data Exchange (ETDEWEB)

    Sakuma, T. [Central Research Inst. of Electric Power Industry, Komae (Japan); Mihara, Y. [Graduate School, Univ. of Electro-Communications, Chofu (Japan); Ochi, Y. [Univ. of Electro-Communications, Chofu (Japan); Ozawa, M. [NEC Tokin, Co., Sendai (Japan); Okita, K. [Graduate School, Ehime Univ., Matsuyama (Japan); Okabe, N. [Ehime Univ., Matsuyama (Japan)

    2005-07-01

    Ti-Ni-Nb shape memory alloy has a wide transformation hysteresis, and has been used as coupling devices and so on. However systematic researches of the influence of the amount of Nb addition on transformation temperatures are few. The purpose of this work is to clarify the influences of pre-strain and Nb content on transformation temperatures in Ti-Ni-Nb shape memory alloys. The specimens were Ti-Ni-Nb alloys (Ni/Ti=1.0, Nb=0-15at%), annealed at 1223 K for 0.3 ks. The variation of transformation temperatures with pre-strain and Nb content were investigated experimentally. The variation of A{sub s}, M{sub s} and transformation temperature hysteresis with pre-strain and Nb content will be discussed in relation to the elastic strain energy and the volume fraction of slip-deformed martensite. (orig.)

  7. High temperature deformation of 6061 Al

    Energy Technology Data Exchange (ETDEWEB)

    Kyungtae Park; Lavernia, E.J.; Mohamed, F.A. (Univ. of California, Irvine (United States). Dept. of Mechanical and Aerospace Engineering)

    1994-03-01

    The creep behavior of powder metallurgy (PM) 6061 Al, which has been used as a metal matrix alloy in the development of discontinuous silicon carbide reinforced aluminum (SiC-Al) composites, has been studied over six orders of magnitude of strain rate. The experimental data show that the steady-state stage of the creep curve is of short duration; that the stress dependence of creep rate is high and variable; and that the temperature dependence of creep rate is much higher than that for self-diffusion in aluminum. The above creep characteristics are different from those documented for aluminum based solid-solution alloys but are similar to those reported for discontinuous SiC-Al composites and dispersion-strengthened (DS) alloys. Analysis of the experimental data shows that while the high stress dependence of creep rate in 6061 Al, like that in DS alloys, can be explained in terms of a threshold stress for creep, the strong temperature dependence of creep rate in the alloy is incompatible with the predictions of available threshold stress models and theoretical treatments proposed for DS alloys.

  8. Development of High Temperature Gas Sensor Technology

    Science.gov (United States)

    Hunter, Gary W.; Chen, Liang-Yu; Neudeck, Philip G.; Knight, Dak; Liu, Chung-Chiun; Wu, Quing-Hai; Zhou, Huan-Jun

    1997-01-01

    The measurement of engine emissions is important for their monitoring and control. However, the ability to measure these emissions in-situ is limited. We are developing a family of high temperature gas sensors which are intended to operate in harsh environments such as those in an engine. The development of these sensors is based on progress in two types of technology: (1) The development of SiC-based semiconductor technology; and (2) Improvements in micromachining and microfabrication technology. These technologies are being used to develop point-contact sensors to measure gases which are important in emission control especially hydrogen, hydrocarbons, nitrogen oxides, and oxygen. The purpose of this paper is to discuss the development of this point-contact sensor technology. The detection of each type of gas involves its own challenges in the fields of materials science and fabrication technology. Of particular importance is sensor sensitivity, selectivity, and stability in long-term, high temperature operation. An overview is presented of each sensor type with an evaluation of its stage of development. It is concluded that this technology has significant potential for use in engine applications but further development is necessary.

  9. Hole-doped cuprate high temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Chu, C.W.; Deng, L.Z.; Lv, B.

    2015-07-15

    Highlights: • Historical discoveries of hole-doped cuprates and representative milestone work. • Several simple and universal scaling laws of the hole-doped cuprates. • A comprehensive classification list with references for hole-doped cuprates. • Representative physical parameters for selected hole-doped cuprates. - Abstract: Hole-doped cuprate high temperature superconductors have ushered in the modern era of high temperature superconductivity (HTS) and have continued to be at center stage in the field. Extensive studies have been made, many compounds discovered, voluminous data compiled, numerous models proposed, many review articles written, and various prototype devices made and tested with better performance than their nonsuperconducting counterparts. The field is indeed vast. We have therefore decided to focus on the major cuprate materials systems that have laid the foundation of HTS science and technology and present several simple scaling laws that show the systematic and universal simplicity amid the complexity of these material systems, while referring readers interested in the HTS physics and devices to the review articles. Developments in the field are mostly presented in chronological order, sometimes with anecdotes, in an attempt to share some of the moments of excitement and despair in the history of HTS with readers, especially the younger ones.

  10. High-temperature ordered intermetallic alloys V

    Energy Technology Data Exchange (ETDEWEB)

    Baker, I. (ed.) (Dartmouth Coll., Hanover, NH (United States). Thayer School of Engineering); Darolia, R. (ed.) (GE Aircraft Engines, Cincinnati, OH (United States)); Whittenberger, J.D. (ed.) (NASA, Cleveland, OH (United States). Lewis Research Center); Yoo, M.H. (ed.) (Oak Ridge National Lab., TN (United States))

    1993-01-01

    These proceedings represent the written record of the High-Temperature Ordered Intermetallic Alloys 5 Symposium which was held in conjunction with the 1992 Fall Materials Research Society meeting in Boston, Massachusetts. This symposium, which was the fifth in the series originated by C.C Koch, C.T. Liu and N.S. Stoloff in 1984, was very successful with 86 oral presentations over four days, and approximately 140 posters given during two lively evening sessions. Such a response, in view of the increasing number of conferences being held on intermetallics each year, reveals the continued high regard for this series of symposia. Individual papers have been processed separately for inclusion in the appropriate data bases.

  11. 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...

  12. Cast Aluminum Alloy for High Temperature Applications

    Science.gov (United States)

    Lee, Jonathan A.

    2003-01-01

    Originally developed by NASA as high performance piston alloys to meet U.S. automotive legislation requiring low exhaust emission, the novel NASA alloys now offer dramatic increase in tensile strength for many other applications at elevated temperatures from 450 F (232 C) to about 750 F (400 C). It is an ideal low cost material for cast automotive components such as pistons, cylinder heads, cylinder liners, connecting rods, turbo chargers, impellers, actuators, brake calipers and rotors. It can be very economically produced from conventional permanent mold, sand casting or investment casting, with silicon content ranging from 6% to 18%. At high silicon levels, the alloy exhibits excellent dimensional stability, surface hardness and wear resistant properties.

  13. 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.

  14. Temperature shapes coral-algal symbiosis in the South China Sea

    Science.gov (United States)

    Tong, Haoya; Cai, Lin; Zhou, Guowei; Yuan, Tao; Zhang, Weipeng; Tian, Renmao; Huang, Hui; Qian, Pei-Yuan

    2017-01-01

    With the increase in sea surface temperature (SST), scleractinian corals are exposed to bleaching threats but may possess certain flexibilities in terms of their associations with symbiotic algae. Previous studies have shown a close symbiosis between coral the and Symbiodinium; however, the spatial variation of the symbiosis and the attribution underlying are not well understood. In the present study, we examined coral-algal symbiosis in Galaxea fascicularis and Montipora spp. from three biogeographic regions across ~10° of latitude in the South China Sea. Analysis of similarities (ANOSIM) indicated a highly flexible coral-algal symbiosis in both G. fascicularis and Montipora spp. and canonical correspondence analysis (CCA) showed that temperature explained 83.2% and 60.1% of the explanatory subclade variations in G. fascicularis and Montipora spp., respectively, which suggested that temperature was the main environmental factor contributing to the diversity of Symbiodinium across the three regions. The geographic specificity of the Symbiodinium phylogeny was identified, revealing possible environmental selection across the three regions. These results suggest that scleractinian corals may have the ability to regulate Symbiodinium community structures under different temperatures and thus be able to adapt to gradual climate change.

  15. Temperature shapes coral-algal symbiosis in the South China Sea

    Science.gov (United States)

    Tong, Haoya; Cai, Lin; Zhou, Guowei; Yuan, Tao; Zhang, Weipeng; Tian, Renmao; Huang, Hui; Qian, Pei-Yuan

    2017-01-01

    With the increase in sea surface temperature (SST), scleractinian corals are exposed to bleaching threats but may possess certain flexibilities in terms of their associations with symbiotic algae. Previous studies have shown a close symbiosis between coral the and Symbiodinium; however, the spatial variation of the symbiosis and the attribution underlying are not well understood. In the present study, we examined coral-algal symbiosis in Galaxea fascicularis and Montipora spp. from three biogeographic regions across ~10° of latitude in the South China Sea. Analysis of similarities (ANOSIM) indicated a highly flexible coral-algal symbiosis in both G. fascicularis and Montipora spp. and canonical correspondence analysis (CCA) showed that temperature explained 83.2% and 60.1% of the explanatory subclade variations in G. fascicularis and Montipora spp., respectively, which suggested that temperature was the main environmental factor contributing to the diversity of Symbiodinium across the three regions. The geographic specificity of the Symbiodinium phylogeny was identified, revealing possible environmental selection across the three regions. These results suggest that scleractinian corals may have the ability to regulate Symbiodinium community structures under different temperatures and thus be able to adapt to gradual climate change. PMID:28084322

  16. Shape Memory Micro- and Nanowire Libraries for the High-Throughput Investigation of Scaling Effects.

    Science.gov (United States)

    Oellers, Tobias; König, Dennis; Kostka, Aleksander; Xie, Shenqie; Brugger, Jürgen; Ludwig, Alfred

    2017-09-11

    The scaling behavior of Ti-Ni-Cu shape memory thin-film micro- and nanowires of different geometry is investigated with respect to its influence on the martensitic transformation properties. Two processes for the high-throughput fabrication of Ti-Ni-Cu micro- to nanoscale thin film wire libraries and the subsequent investigation of the transformation properties are reported. The libraries are fabricated with compositional and geometrical (wire width) variations to investigate the influence of these parameters on the transformation properties. Interesting behaviors were observed: Phase transformation temperatures change in the range from 1 to 72 °C (austenite finish, (A f ), 13 to 66 °C (martensite start, M s ) and the thermal hysteresis from -3.5 to 20 K. It is shown that a vanishing hysteresis can be achieved for special combinations of sample geometry and composition.

  17. Cellular basis of morphological variation and temperature-related plasticity in Drosophila melanogaster strains with divergent wing shapes.

    Science.gov (United States)

    Torquato, Libéria Souza; Mattos, Daniel; Matta, Bruna Palma; Bitner-Mathé, Blanche Christine

    2014-12-01

    Organ shape evolves through cross-generational changes in developmental patterns at cellular and/or tissue levels that ultimately alter tissue dimensions and final adult proportions. Here, we investigated the cellular basis of an artificially selected divergence in the outline shape of Drosophila melanogaster wings, by comparing flies with elongated or rounded wing shapes but with remarkably similar wing sizes. We also tested whether cellular plasticity in response to developmental temperature was altered by such selection. Results show that variation in cellular traits is associated with wing shape differences, and that cell number may play an important role in wing shape response to selection. Regarding the effects of developmental temperature, a size-related plastic response was observed, in that flies reared at 16 °C developed larger wings with larger and more numerous cells across all intervein regions relative to flies reared at 25 °C. Nevertheless, no conclusive indication of altered phenotypic plasticity was found between selection strains for any wing or cellular trait. We also described how cell area is distributed across different intervein regions. It follows that cell area tends to decrease along the anterior wing compartment and increase along the posterior one. Remarkably, such pattern was observed not only in the selected strains but also in the natural baseline population, suggesting that it might be canalized during development and was not altered by the intense program of artificial selection for divergent wing shapes.

  18. Diffusion phenomena in coatings for high temperature service

    Energy Technology Data Exchange (ETDEWEB)

    Zambon, A.; Ramous, E.

    1987-04-01

    The chemical composition modifications of Ni-Co-Cr-Al-Y coatings obtained by physical vapour deposition on the nickel-based superalloy Udimet 520 has been studied and related to soaking times ranging from 500 to 2000 h. The local compositions of both the coating and the base material are continuously changing because of diffusion phenomena, the growth of precipitates and surface oxidation. Electron microscopy examination and X-ray diffraction analysis showed that the zone near the interface tends to become sigma phase prone, thus affecting structural stability in a negative way. The shapes of the concentration profile show the reactive diffusion takes place after a period of high temperature exposure. Diffusion coefficients seem to depend on local concentration values and decrease with increasing soaking time.

  19. 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

  20. Ceramic membranes for high temperature hydrogen separation

    Energy Technology Data Exchange (ETDEWEB)

    Fain, D.E.; Roettger, G.E. [Oak Ridge K-25 Site, TN (United States)

    1996-08-01

    Ceramic gas separation membranes can provide very high separation factors if the pore size is sufficiently small to separate gas molecules by molecular sieving and if oversized pores are adequately limited. Ceramic membranes typically have some pores that are substantially larger than the mean pore size and that should be regarded as defects. To assess the effects of such defects on the performance of ceramic membranes, a simple mathematical model has been developed to describe flow through a gas separation membrane that has a primary mode of flow through very small pores but that has a secondary mode of flow through undesirably large pores. This model permits separation factors to be calculated for a specified gas pair as a function of the molecular weights and molecular diameters of the gases, the membrane pore diameter, and the diameter and number of defects. This model will be described, and key results from the model will be presented. The separation factors of the authors membranes continue to be determined using a permeance test system that measures flows of pure gases through a membrane at temperatures up to 275{degrees}C. A primary goal of this project for FY 1996 is to develop a mixed gas separation system for measuring the separation efficiency of membranes at higher temperatures. Performance criteria have been established for the planned mixed gas separation system and design of the system has been completed. The test system is designed to measure the separation efficiency of membranes at temperatures up to 600{degrees}C and pressures up to 100 psi by separating the constituents of a gas mixture containing hydrogen. The system will accommodate the authors typical experimental membrane that is tubular and has a diameter of about 9 mm and a length of about 23 cm. The design of the new test system and its expected performance will be discussed.

  1. High-temperature enzymatic breakdown of cellulose.

    Science.gov (United States)

    Wang, Hongliang; Squina, Fabio; Segato, Fernando; Mort, Andrew; Lee, David; Pappan, Kirk; Prade, Rolf

    2011-08-01

    Cellulose is an abundant and renewable biopolymer that can be used for biofuel generation; however, structural entrapment with other cell wall components hinders enzyme-substrate interactions, a key bottleneck for ethanol production. Biomass is routinely subjected to treatments that facilitate cellulase-cellulose contacts. Cellulases and glucosidases act by hydrolyzing glycosidic bonds of linear glucose β-1,4-linked polymers, producing glucose. Here we describe eight high-temperature-operating cellulases (TCel enzymes) identified from a survey of thermobacterial and archaeal genomes. Three TCel enzymes preferentially hydrolyzed soluble cellulose, while two preferred insoluble cellulose such as cotton linters and filter paper. TCel enzymes had temperature optima ranging from 85°C to 102°C. TCel enzymes were stable, retaining 80% of initial activity after 120 h at 85°C. Two modes of cellulose breakdown, i.e., with endo- and exo-acting glucanases, were detected, and with two-enzyme combinations at 85°C, synergistic cellulase activity was observed for some enzyme combinations.

  2. Use of chiral cell shape to ensure highly directional swimming in trypanosomes.

    Science.gov (United States)

    Wheeler, Richard John

    2017-01-01

    Swimming cells typically move along a helical path or undergo longitudinal rotation as they swim, arising from chiral asymmetry in hydrodynamic drag or propulsion bending the swimming path into a helix. Helical paths are beneficial for some forms of chemotaxis, but why asymmetric shape is so prevalent when a symmetric shape would also allow highly directional swimming is unclear. Here, I analyse the swimming of the insect life cycle stages of two human parasites; Trypanosoma brucei and Leishmania mexicana. This showed quantitatively how chirality in T. brucei cell shape confers highly directional swimming. High speed videomicrographs showed that T. brucei, L. mexicana and a T. brucei RNAi morphology mutant have a range of shape asymmetries, from wild-type T. brucei (highly chiral) to L. mexicana (near-axial symmetry). The chiral cells underwent longitudinal rotation while swimming, with more rapid longitudinal rotation correlating with swimming path directionality. Simulation indicated hydrodynamic drag on the chiral cell shape caused rotation, and the predicted geometry of the resulting swimming path matched the directionality of the observed swimming paths. This simulation of swimming path geometry showed that highly chiral cell shape is a robust mechanism through which microscale swimmers can achieve highly directional swimming at low Reynolds number. It is insensitive to random variation in shape or propulsion (biological noise). Highly symmetric cell shape can give highly directional swimming but is at risk of giving futile circular swimming paths in the presence of biological noise. This suggests the chiral T. brucei cell shape (associated with the lateral attachment of the flagellum) may be an adaptation associated with the bloodstream-inhabiting lifestyle of this parasite for robust highly directional swimming. It also provides a plausible general explanation for why swimming cells tend to have strong asymmetries in cell shape or propulsion.

  3. Use of chiral cell shape to ensure highly directional swimming in trypanosomes.

    Directory of Open Access Journals (Sweden)

    Richard John Wheeler

    2017-01-01

    Full Text Available Swimming cells typically move along a helical path or undergo longitudinal rotation as they swim, arising from chiral asymmetry in hydrodynamic drag or propulsion bending the swimming path into a helix. Helical paths are beneficial for some forms of chemotaxis, but why asymmetric shape is so prevalent when a symmetric shape would also allow highly directional swimming is unclear. Here, I analyse the swimming of the insect life cycle stages of two human parasites; Trypanosoma brucei and Leishmania mexicana. This showed quantitatively how chirality in T. brucei cell shape confers highly directional swimming. High speed videomicrographs showed that T. brucei, L. mexicana and a T. brucei RNAi morphology mutant have a range of shape asymmetries, from wild-type T. brucei (highly chiral to L. mexicana (near-axial symmetry. The chiral cells underwent longitudinal rotation while swimming, with more rapid longitudinal rotation correlating with swimming path directionality. Simulation indicated hydrodynamic drag on the chiral cell shape caused rotation, and the predicted geometry of the resulting swimming path matched the directionality of the observed swimming paths. This simulation of swimming path geometry showed that highly chiral cell shape is a robust mechanism through which microscale swimmers can achieve highly directional swimming at low Reynolds number. It is insensitive to random variation in shape or propulsion (biological noise. Highly symmetric cell shape can give highly directional swimming but is at risk of giving futile circular swimming paths in the presence of biological noise. This suggests the chiral T. brucei cell shape (associated with the lateral attachment of the flagellum may be an adaptation associated with the bloodstream-inhabiting lifestyle of this parasite for robust highly directional swimming. It also provides a plausible general explanation for why swimming cells tend to have strong asymmetries in cell shape or propulsion.

  4. 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.

  5. Robust high temperature oxygen sensor electrodes

    DEFF Research Database (Denmark)

    Lund, Anders

    reaction kinetics. At oxygen partial pressures below 10-6 bar at 700 C, the mass transport processes dominated the response time. The response time increased with decreasing oxygen partial pressure and inlet gas flow rate. A series of porous platinum electrodes were impregnated with the ionically...... conducting gadolinium-doped cerium oxide (CGO). The addition of CGO was found to decrease the polarisation resistance of the oxygen reaction by up to an order of magnitude compared with a single phase platinum electrode by increasing the effective triple phase boundary (TPB) length. It did not have any......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...

  6. Filter unit for use at high temperatures

    Science.gov (United States)

    Ciliberti, David F.; Lippert, Thomas E.

    1988-01-01

    A filtering unit for filtering particulates from high temperature gases uses a spiral ceramic spring to bias a ceramic, tubular filter element into sealing contact with a flange about an aperture of a metallic tube sheet. The ceramic spiral spring may contact the upper edge of the filter element and be restrained by a stop member spaced from one end of the tube sheet, or the spring may contact the bottom of the filter element and be restrained by a support member spaced from the opposite end of the tube sheet. The stop member and support member are adjustably secured to the tube sheet. A filtering system uses the ceramic spiral spring to bias a plurality of ceramic, tubular filter elements in a respective plurality of apertures in a tube sheet which divides a vessel into upper and lower enclosed sections.

  7. Toroidal high temperature superconducting coils for ISTTOK

    Energy Technology Data Exchange (ETDEWEB)

    Fernandes, H., E-mail: hf@ipfn.ist.utl.pt [Associacao Euratom/IST, Instituto de Plasmas e Fusao Nuclear, Laboratorio Associado, Instituto Superior Tecnico, 1049-001 Lisboa (Portugal); Goemoery, F. [Institute of Electrical Engineering, Slovak Academy of Sciences, Dubravska cesta 9, 84104 Bratislava (Slovakia); Corte, A. della; Celentano, G. [ENEA C.R. Frascati, Via E. Fermi 45, 00044 Frascati (Italy); Souc, J. [Institute of Electrical Engineering, Slovak Academy of Sciences, Dubravska cesta 9, 84104 Bratislava (Slovakia); Silva, C.; Carvalho, I.; Gomes, R. [Associacao Euratom/IST, Instituto de Plasmas e Fusao Nuclear, Laboratorio Associado, Instituto Superior Tecnico, 1049-001 Lisboa (Portugal); Di Zenobio, A.; Messina, G. [ENEA C.R. Frascati, Via E. Fermi 45, 00044 Frascati (Italy)

    2011-10-15

    High temperature superconductors (HTS) are very attractive to be used in fusion devices mainly due to lower operations costs. The HTS technology has reached a point where the construction of toroidal field coils for a tokamak is possible. The feasibility of a tokamak operating with HTS is extremely relevant and ISTTOK is the ideal candidate for a meaningful test due to its small size (and consequently lower cost) and the possibility to operate in a steady-state inductive regime. In this paper, a conceptual study of the ISTTOK upgrade to a superconducting device is presented, along with the relevant boundary conditions to achieve a permanent toroidal field with HTS. It is shown that the actual state of the art in HTS allows the design of a toroidal field coil capable of generating the appropriate field on plasma axis while respecting the structural specification of the machine.

  8. A Lithium-Air Battery Stably Working at High Temperature with High Rate Performance.

    Science.gov (United States)

    Pan, Jian; Li, Houpu; Sun, Hao; Zhang, Ye; Wang, Lie; Liao, Meng; Sun, Xuemei; Peng, Huisheng

    2018-02-01

    Driven by the increasing requirements for energy supply in both modern life and the automobile industry, the lithium-air battery serves as a promising candidate due to its high energy density. However, organic solvents in electrolytes are likely to rapidly vaporize and form flammable gases under increasing temperatures. In this case, serious safety problems may occur and cause great harm to people. Therefore, a kind of lithium-air that can work stably under high temperature is desirable. Herein, through the use of an ionic liquid and aligned carbon nanotubes, and a fiber shaped design, a new type of lithium-air battery that can effectively work at high temperatures up to 140 °C is developed. Ionic liquids can offer wide electrochemical windows and low vapor pressures, as well as provide high thermal stability for lithium-air batteries. The aligned carbon nanotubes have good electric and heat conductivity. Meanwhile, the fiber format can offer both flexibility and weavability, and realize rapid heat conduction and uniform heat distribution of the battery. In addition, the high temperature has also largely improved the specific powers by increasing the ionic conductivity and catalytic activity of the cathode. Consequently, the lithium-air battery can work stably at 140 °C with a high specific current of 10 A g -1 for 380 cycles, indicating high stability and good rate performance at high temperatures. This work may provide an effective paradigm for the development of high-performance energy storage devices. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  9. High temperature triaxial tests on Rochester shale

    Science.gov (United States)

    Bruijn, Rolf; Burlini, Luigi; Misra, Santanu

    2010-05-01

    Phyllosilicates are one of the major components of the crust, responsible for strength weakening during deformation. High pressure and temperature experiments of natural samples rich in phyllosilicates are needed to test the relevance of proposed weakening mechanisms induced by phyllosilicates, derived from lab experiments on single phase and synthetic polyphase rocks and single crystals. Here, we present the preliminary results of a series of high temperature triaxial tests performed on the illite-rich Rochester Shale (USA - New York) using a Paterson type gas-medium HPT testing machine. Cylindrical samples with homogeneous microstructure and 12-14% porosity were fabricated by cold and hot-isostatically pressing, hot-pressed samples were deformed up to a total shortening of 7.5 to 13%. To study the significance of mica dehydration, iron or copper jackets were used in combination with non-porous or porous spacers. Water content was measured before and after experiments using Karl Fischer Titration (KFT). All experiments show, after yielding at 0.6% strain, rapid hardening in nearly linear fashion until about 4-5% strain, from where stress increases at reducing rates to values at 10% strain, between 400 and 675 MPa, depending on experimental conditions. Neither failure nor steady state however, is achieved within the maximum strain of 13%. Experiments performed under 500 °C and 300 MPa confining pressure show weak strain rate dependence. In addition, iron-jacketed samples appear harder than copper-jacketed ones. At 700 °C samples are 17 to 37% weaker and more sensitive to strain rate than during 500 °C experiments. Although, iron-jacketed samples behave stronger than copper-jacketed ones. By visual inspection, samples appear homogeneously shortened. Preliminary analysis suggests that deformation is mostly accommodated by pore collapse. Although, with finite strain, pore collapse becomes less significant. A temperature, strain rate and jacket material dependent

  10. High Molecular Weight Polybenzimidazole Membranes for High Temperature PEMFC

    DEFF Research Database (Denmark)

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

    2014-01-01

    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......Da with good solubility in organic solvents. Membranes fabricated from the polymers were systematically characterized in terms of oxidative stability, acid doping and swelling, conductivity, mechanical strength and fuel cell performance and durability. With increased molecular weights the polymer membranes...

  11. The shapes of cold, high mountains in sedimentary rocks

    Science.gov (United States)

    Cruden, D. M.

    2003-09-01

    Terzaghi (Geotechnique 12 (1962) 251) and Young (Young, A., 1972. Slopes. Oliver and Boyd, Edinburgh, 288 pp.) described the stable forms of slopes in sedimentary rock masses, assuming penetrative discontinuities, which are parallel to bedding and joints which are perpendicular to bedding. The only movements considered were slides along bedding. Experience in the Canadian Rockies indicates that the cohesionless rock masses that exist at or above tree line may also move by toppling, buckling and sliding along joints. These processes also act to limit the inclinations of stable slopes. Rock strength is a factor in the critical height of a slope that buckles. The processes can be represented as fields on a process diagram, a plot of slope inclination against bedding dip, using the basic friction angles of the rocks present. The process diagram also separates five common mountain peak shapes, which form on homoclinal sequences of beds. Castellate and Matterhorn mountains occur in sub-horizontal beds, cuestas develop in gently to moderately dipping beds. Hogbacks formed in moderately to steeply dipping beds have similar slope angles on both cataclinal and anaclinal slopes. Dogtooth mountains occur in steeply dipping sub-vertical beds.

  12. Extreme temperatures in the adult stage shape delayed effects of larval pesticide stress: a comparison between latitudes.

    Science.gov (United States)

    Janssens, Lizanne; Dinh Van, Khuong; Stoks, Robby

    2014-03-01

    Global warming and pesticide pollution are major threats for aquatic biodiversity. Yet, how pesticide effects are influenced by the increased frequency of extreme temperatures under global warming and how local thermal adaptation may mitigate these effects is unknown. We therefore investigated the combined impact of larval chlorpyrifos exposure, larval food stress and adult heat exposure on a set of fitness-related traits in replicated low- and high-latitude populations of the damselfly Ischnura elegans. Larval pesticide exposure resulted in lighter adults with a higher water content, lower fat content, higher Hsp70 levels and a lower immune function (PO activity). Heat exposure reduced water content, mass, fat content and flying ability. Importantly, both stressors interacted across metamorphosis: adult heat exposure lowered the reduction of fat content, and generated a stronger decrease in PO activity in pesticide-exposed animals. Larval pesticide exposure and larval food stress also reduced the defense response to the adult heat stress in terms of increased Hsp70 levels. In line with strong life history differences in the unstressed control situation, high-latitude animals were less sensitive to food stress (body mass and water content), but more sensitive to pesticide stress (development time and PO activity) and heat exposure (PO activity and Hsp70 levels). While low-latitude adults could better withstand the extreme temperature as suggested by the weaker increase in Hsp70, heat exposure similarly affected the delayed effects of larval pesticide exposure at both latitudes. Our study highlighted two key findings relevant for ecological risk assessment under global warming. Firstly, the delayed effects of larval pesticide exposure on adult damselflies depended upon subsequent adult heat exposure, indicating that larval pesticide stress and adult heat stress interacted across metamorphosis. Secondly, low- and high-latitude animals responded differently to the

  13. HIGH TEMPERATURE HIGH PRESSURE THERMODYNAMIC MEASUREMENTS FOR COAL MODEL COMPOUNDS

    Energy Technology Data Exchange (ETDEWEB)

    Vinayak N. Kabadi

    2000-05-01

    The flow VLE apparatus designed and built for a previous project was upgraded and recalibrated for data measurements for this project. The modifications include better and more accurate sampling technique, addition of a digital recorder to monitor temperature and pressure inside the VLE cell, and a new technique for remote sensing of the liquid level in the cell. VLE data measurements for three binary systems, tetralin-quinoline, benzene--ethylbenzene and ethylbenzene--quinoline, have been completed. The temperature ranges of data measurements were 325 C to 370 C for the first system, 180 C to 300 C for the second system, and 225 C to 380 C for the third system. The smoothed data were found to be fairly well behaved when subjected to thermodynamic consistency tests. SETARAM C-80 calorimeter was used for incremental enthalpy and heat capacity measurements for benzene--ethylbenzene binary liquid mixtures. Data were measured from 30 C to 285 C for liquid mixtures covering the entire composition range. An apparatus has been designed for simultaneous measurement of excess volume and incremental enthalpy of liquid mixtures at temperatures from 30 C to 300 C. The apparatus has been tested and is ready for data measurements. A flow apparatus for measurement of heat of mixing of liquid mixtures at high temperatures has also been designed, and is currently being tested and calibrated.

  14. 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

  15. 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.

  16. Aircraft Reconstruction in High-Resolution SAR Images Using Deep Shape Prior

    Directory of Open Access Journals (Sweden)

    Fangzheng Dou

    2017-10-01

    Full Text Available Contour shapes are important features. An accurate contour shape of a target can provide important prior information for applications, such as target recognition, which can improve the accuracy of target interpretation. In this paper, a synthetic aperture radar (SAR target reconstruction method is proposed, which can be used to reconstruct the target by using shape priors to perform an accurate extraction of the contour shape feature. The method is divided into two stages. In the deep shape prior extraction stage, a generative deep learning modelling method is used to obtain deep shape priors. In the reconstruction stage, a novel coarse-to-fine pose estimation method combined with an optimization algorithm is proposed, which integrates deep shape priors into the process of reconstruction. Specifically, to address the issue of object rotation, candidate poses are obtained using the coarse pose estimation method, which avoids an exhaustive search of each pose. In addition, an energy function composed of a scattering term and shape term to combine the fine pose estimation, is constructed and optimized via an iterative optimization algorithm to achieve the goal of object reconstruction. To the best of our knowledge, this is the first time shape priors have been used to extract shape features of SAR targets. Experiments are conducted on a data set acquired by TerraSAR-X images and the results demonstrate the high accuracy and robustness of the proposed method.

  17. 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.

  18. Ultra Low Density and Highly Crosslinked Biocompatible Shape Memory Polyurethane Foams

    OpenAIRE

    Singhal, Pooja; Rodriguez, Jennifer N.; Small, Ward; Eagleston, Scott; Van de Water, Judy; Maitland, Duncan J.; Wilson, Thomas S.

    2012-01-01

    We report the development of highly chemically crosslinked, ultra low density (~0.015 g/cc) polyurethane shape memory foams synthesized from symmetrical, low molecular weight and branched hydroxyl monomers. Sharp single glass transitions (Tg) customizable in the functional range of 45–70 °C were achieved. Thermomechanical testing confirmed shape memory behavior with 97–98% shape recovery over repeated cycles, a glassy storage modulus of 200–300 kPa and recovery stresses of 5–15 kPa. Shape hol...

  19. High Temperature High Pressure Thermodynamic Measurements for Coal Model Compounds

    Energy Technology Data Exchange (ETDEWEB)

    John C. Chen; Vinayak N. Kabadi

    1998-11-12

    The overall objective of this project is to develop a better thermodynamic model for predicting properties of high-boiling coal derived liquids, especially the phase equilibria of different fractions at elevated temperatures and pressures. The development of such a model requires data on vapor-liquid equilibria (VLE), enthalpy, and heat capacity which would be experimentally determined for binary systems of coal model compounds and compiled into a database. The data will be used to refine existing models such as UNIQUAC and UNIFAC. The flow VLE apparatus designed and built for a previous project was upgraded and recalibrated for data measurements for thk project. The modifications include better and more accurate sampling technique and addition of a digital recorder to monitor temperature, pressure and liquid level inside the VLE cell. VLE data measurements for system benzene-ethylbenzene have been completed. The vapor and liquid samples were analysed using the Perkin-Elmer Autosystem gas chromatography.

  20. Rapid sulfur capture studies at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Richards, G.A.; Lawson, W.F.; Maloney, D.J.; Shaw, D.W.

    1990-12-01

    Determine conditions that would reproduce optimum sulfur capture ( super-equilibrium'') behavior. No attempt was made to extract kinetic data for calcination or sulfur capture, as might be done in a comprehensive study of sorbent behavior. While some interesting anomalies are present in the calcination data and in the limited surface area data, no attempt was made to pursue those issues. Since little sulfur capture was observed at operating conditions where super-equilibrium'' might be expected to occur, tests were stopped when the wide range of parameters that were studied failed to produce significant sulfur capture via the super-equilibrium mechanism. Considerable space in this report is devoted to a description of the experiment, including details of the GTRC construction. This description is included because we have received requests for a detailed description of the GTRC itself, as well as the pressurized dry powder feed system. In addition, many questions about accurately sampling the sulfur species from a high-temperature, high-pressure reactor were raised during the course of this investigation. A full account of the development of the gas and particulate sampling train in thus provided. 8 refs., 17 figs., 2 tabs.

  1. 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...

  2. 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?

  3. 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.

  4. The Effects of Verbal Instruction and Shaping to Improve Tackling by High School Football Players

    Science.gov (United States)

    Harrison, Antonio M.; Pyles, David A.

    2013-01-01

    We evaluated verbal instruction and shaping using TAG (teaching with acoustical guidance) to improve tackling by 3 high school football players. Verbal instruction and shaping improved tackling for all 3 participants. In addition, performance was maintained as participants moved more quickly through the tackling procedure.

  5. STUDY OF SAMPLE AND HOLD DIGITAL-ANALOG CONVERTER WITH HIGH ORDER JITTER NOISE SHAPING

    OpenAIRE

    北原, 義大; KITAHARA, Yoshihiro

    2014-01-01

    In this paper, present sample hold DAC with high order jitter noise shaping using 2nd order architecture or feed-forward 2nd order architecture. Performance improvements of sample hold DAC can be expected by using higher order jitter noise shaping. The effectiveness of presented architecture is confirmed by MATLAB simulation results and SPICE simulation results.

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

    Science.gov (United States)

    Halbig, Michael C.; Singh, Mrityunjay

    2015-01-01

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

  7. Room temperature synthesis of high temperature stable lanthanum phosphate–yttria nano composite

    Energy Technology Data Exchange (ETDEWEB)

    Sankar, Sasidharan; Raj, Athira N.; Jyothi, C.K. [Material Sciences and Technology Division, National Institute for Interdisciplinary Science and Technology, Council of Scientific and Industrial Research, Thiruvananthapuram 695019 (India); Warrier, K.G.K., E-mail: wwarrierkgk@yahoo.co.in [Material Sciences and Technology Division, National Institute for Interdisciplinary Science and Technology, Council of Scientific and Industrial Research, Thiruvananthapuram 695019 (India); Padmanabhan, P.V.A. [Bhabha Atomic Research Centre, Mumbai 400085 (India)

    2012-07-15

    Graphical abstract: A facile aqueous sol–gel route involving precipitation–peptization mechanism followed by electrostatic stabilization is used for synthesizing nanocrystalline composite containing lanthanum phosphate and yttria. Highlights: ► A novel lanthanum phosphate–Y{sub 2}O{sub 3} nano composite is synthesized for the first time using a modified facile sol gel process. ► The composite becomes crystalline at 600 °C and X-ray diffraction pattern is indexed for monoclinic LaPO{sub 4} and cubic yttria. ► The composite synthesized was tested up to 1300 °C and no reaction between the phases of the constituents is observed with the morphologies of the phases being retained. -- Abstract: A facile aqueous sol–gel route involving precipitation–peptization mechanism followed by electrostatic stabilization is used for synthesizing nanocrystalline composite containing lanthanum phosphate and yttria. Lanthanum phosphate (80 wt%)–yttria (20 wt%) nano composite (LaPO{sub 4}–20%Y{sub 2}O{sub 3}), has an average particle size of ∼70 nm after heat treatment of precursor at 600 °C. TG–DTA analysis reveals that stable phase of the composite is formed on heating the precursor at 600 °C. The TEM images of the composite show rod shape morphology of LaPO{sub 4} in which yttria is acquiring near spherical shape. Phase identification of the composite as well as the phase stability up to 1300 °C was carried out using X-ray diffraction technique. With the phases being stable at higher temperatures, the composite synthesized should be a potential material for high temperature applications like thermal barrier coatings and metal melting applications.

  8. Exploiting NiTi shape memory alloy films in design of tunable high frequency microcantilever resonators

    Science.gov (United States)

    Stachiv, I.; Sittner, P.; Olejnicek, J.; Landa, M.; Heller, L.

    2017-11-01

    Shape memory alloy (SMA) films are very attractive materials for microactuators because of their high energy density. However, all currently developed SMA actuators utilize martensitic transformation activated by periodically generated heating and cooling; therefore, they have a slow actuation speed, just a few Hz, which restricts their use in most of the nanotechnology applications such as high frequency microcantilever based physical and chemical sensors, atomic force microscopes, or RF filters. Here, we design tunable high frequency SMA microcantilevers for nanotechnology applications. They consist of a phase transforming NiTi SMA film sputtered on the common elastic substrate material; in our case, it is a single-crystal silicon. The reversible tuning of microcantilever resonant frequencies is then realized by intentionally changing the Young's modulus and the interlayer stress of the NiTi film by temperature, while the elastic substrate guarantees the high frequency actuation (up to hundreds of kHz) of the microcantilever. The experimental results qualitatively agree with predictions obtained from the dedicated model based on the continuum mechanics theory and a phase characteristic of NiTi. The present design of SMA microcantilevers expands the capability of current micro-/nanomechanical resonators by enabling tunability of several consecutive resonant frequencies.

  9. Summation of all petal-shaped diagrams in O(N) model near the phase transition temperature

    CERN Document Server

    Bordag, M

    2002-01-01

    The temperature phase transition in the theory of the N-component scalar field is studied. The weak phase transition of the first order is obtained in the approximation of summation of all petal-shaped diagrams. By the N -> infinity it becomes the phase transition of the second order. The comparison with other approaches is carried out. The necessary data on the Legendre transformation of the second order and Schwinger-Dyson equations are presented. The gap equations are solved in the approximation of summation of all petal-shaped diagrams for the arbitrary N

  10. Structural changes in high-temperature synthesis of luminescent alumina ceramics

    Science.gov (United States)

    Zvonarev, S. V.; Kortov, V. S.; Ryabinina, M. V.; Kiryakov, A. N.

    2016-08-01

    Scanning electron microscopy was used to study structural changes in luminescent alumina ceramics which was synthesized from nanopowder at high temperatures in reducing environment. An effect of synthesis parameters on size-distribution of grains, their shape and a number of pores in the samples under study was determined. It was found that in a certain temperature range grains are the same ones in the precursor nanopowder, which is associated with the emergence of nanoparticles of lower aluminum oxides.

  11. High pressure study of high-temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Souliou, Sofia-Michaela

    2014-09-29

    The current thesis studies experimentally the effect of high external pressure on high-T{sub c} superconductors. The structure and lattice dynamics of several members of the high-T{sub c} cuprate and Fe-based superconductors families were investigated by means of Raman spectroscopy and X-ray diffraction under well-controlled, hydrostatic high pressure and low temperature conditions. The lattice dynamics of the high-T{sub c} superconductor YBa{sub 2}Cu{sub 3}O{sub 6+x} have been investigated systematically by Raman spectroscopy as a function of doping (x = 0.95, 0.75, 0.60, 0.55, and 0.45) and external pressure. Under ambient pressure conditions, in addition to the Raman modes expected from group theory, we observe new Raman active phonons upon cooling the underdoped samples, at temperatures well above the superconducting transition temperature. The doping dependence and the onset temperatures of the new Raman features suggest that they are associated with the incommensurate charge density wave (CDW) state recently discovered in underdoped cuprates using synchrotron X-ray scattering techniques. Under high pressure conditions (from 2 to 12 GPa), our Raman measurements on highly ordered underdoped YBa{sub 2}Cu{sub 3}O{sub 6.55} samples do not show any of the new Raman phonons seen at ambient pressure. High pressure and low temperature Raman measurements have been performed on the underdoped superconductor YBa{sub 2}Cu{sub 4}O{sub 8}. A clear renormalization of some of the Raman phonons is seen below T{sub c} as a result of the changes in the phonon self-energy upon the opening of the superconducting gap, with the most prominent one being that of the B{sub 1g}-like buckling phonon mode. The amplitude of this renormalization strongly increases with pressure, resembling the effect of hole doping in YBa{sub 2}Cu{sub 3}O{sub 6+x}. At ∝ 10 GPa, the system undergoes a reversible pressure-induced structural phase transition to a non-centrosymmmetric structure (space group

  12. Spectral shape variation of interstellar electrons at high energies

    Science.gov (United States)

    Tan, L. C.

    1985-01-01

    The high energy electron spectrum analysis has shown that the electron intensity inside the H2 cloud region, or in a spiral arm, should be much lower than that outside it and the observed electron energy spectrum should flatten again at about 1 TeV. In the framework of the leady box model the recently established rigidity dependence of the escape pathlength of cosmic rays would predict a high energy electron spectrum which is flatter than the observed one. This divergence is explained by assuming that the leaky box model can only apply to cosmic ray heavy nuclei, and light nuclei and electrons in cosmic rays may have different behaviors in the interstellar propagation. Therefore, the measured data on high energy electrons should be analyzed based on the proposed nonuniform galactic disk (NUGD) mode.

  13. Analytic Models of High-Temperature Hohlraums

    Energy Technology Data Exchange (ETDEWEB)

    Stygar, W.A.; Olson, R.E.; Spielman, R.B.; Leeper, R.J.

    2000-11-29

    A unified set of high-temperature-hohlraum models has been developed. For a simple hohlraum, P{sub s} = [A{sub s}+(1{minus}{alpha}{sub W})A{sub W}+A{sub H}]{sigma}T{sub R}{sup 4} + (4V{sigma}/c)(dT{sub R}{sup r}/dt) where P{sub S} is the total power radiated by the source, A{sub s} is the source area, A{sub W} is the area of the cavity wall excluding the source and holes in the wall, A{sub H} is the area of the holes, {sigma} is the Stefan-Boltzmann constant, T{sub R} is the radiation brightness temperature, V is the hohlraum volume, and c is the speed of light. The wall albedo {alpha}{sub W} {triple_bond} (T{sub W}/T{sub R}){sup 4} where T{sub W} is the brightness temperature of area A{sub W}. The net power radiated by the source P{sub N} = P{sub S}-A{sub S}{sigma}T{sub R}{sup 4}, which suggests that for laser-driven hohlraums the conversion efficiency {eta}{sub CE} be defined as P{sub N}/P{sub LASER}. The characteristic time required to change T{sub R}{sup 4} in response to a change in P{sub N} is 4V/C[(l{minus}{alpha}{sub W})A{sub W}+A{sub H}]. Using this model, T{sub R}, {alpha}{sub W}, and {eta}{sub CE} can be expressed in terms of quantities directly measurable in a hohlraum experiment. For a steady-state hohlraum that encloses a convex capsule, P{sub N} = {l_brace}(1{minus}{alpha}{sub W})A{sub W}+A{sub H}+[(1{minus}{alpha}{sub C})(A{sub S}+A{sub W}{alpha}{sub W})A{sub C}/A{sub T}]{r_brace}{sigma}T{sub RC}{sup 4} where {alpha}{sub C} is the capsule albedo, A{sub C} is the capsule area, A{sub T} {triple_bond} (A{sub S}+A{sub W}+A{sub H}), and T{sub RC} is the brightness temperature of the radiation that drives the capsule. According to this relation, the capsule-coupling efficiency of the baseline National-Ignition-Facility (NIF) hohlraum is 15% higher than predicted by previous analytic expressions. A model of a hohlraum that encloses a z pinch is also presented.

  14. High Temperature Electrical Insulation Materials for Space Applications Project

    Data.gov (United States)

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

  15. High Temperature Fatigue Life Evaluation Using Small Specimen

    National Research Council Canada - National Science Library

    NOGAMI, Shuhei; HISAKA, Chiaki; FUJIWARA, Masaharu; WAKAI, Eichi; HASEGAWA, Akira

    2017-01-01

    For developing the high temperature fatigue life evaluation method using small specimen, the effect of specimen size and test environment on the high temperature fatigue life of the reduced activation...

  16. 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 Space Shuttle Main Engine (SSME) consists of 1080 conical tubes, which are furnace brazed themselves, manifolds, and surrounding structural jacket making almost four miles of braze joints. Subsequent furnace braze cycles are performed due to localized braze voids between the coolant tubes. SSME nozzle experiences extremely high heat flux (180 mW/sq m) during hot fire. Braze voids between coolant tubes may result in hot combustion gas escape causing jacket bulges. The nozzle can be disqualified for flight or result in mission failure if the braze voids exceed the limits. Localized braze processes were considered to eliminate braze voids, however, damage to the parent materials often prohibited use of such process. Being the only manned flight reusable rocket engine, it has stringent requirement on the braze process. Poor braze quality or damage to the parent materials limits the nozzle service life. The objective of this study was to develop a laser brazing process to provide quality, localized braze joints without adverse affect on the parent materials. Gold (Au-Cu-Ni-Pd-Mn) based high temperature braze alloys were used in both powder and wire form. Thin section iron base superalloy A286 tube was used as substrate materials. Different Laser Systems including CO2 (10.6 micrometers, 1kW), ND:YAG (1.06 micrometers, 4kW). and direct diode laser (808nm. 150W) were investigated for brazing process. The laser process variables including wavelength. laser power, travel speed and angle of inclination were optimized according to bead geometry and braze alloy wetting at minimum heat input level, The properties of laser brazing were compared to that of furnace brazing. Microhardness profiles were used for braze joint property comparison between laser and furnace brazing. The cooling rate of laser brazing was compared to furnace brazing based on secondary dendritic arm spacing, Both optical and Scanning Electron Microscope (SEM) were used to evaluate the microstructures of

  17. Measuring Specific Heats at High Temperatures

    Science.gov (United States)

    Vandersande, Jan W.; Zoltan, Andrew; Wood, Charles

    1987-01-01

    Flash apparatus for measuring thermal diffusivities at temperatures from 300 to 1,000 degrees C modified; measures specific heats of samples to accuracy of 4 to 5 percent. Specific heat and thermal diffusivity of sample measured. Xenon flash emits pulse of radiation, absorbed by sputtered graphite coating on sample. Sample temperature measured with thermocouple, and temperature rise due to pulse measured by InSb detector.

  18. 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.

  19. DNA sequence–directed shape change of photopatterned hydrogels via high-degree swelling

    Science.gov (United States)

    Cangialosi, Angelo; Yoon, ChangKyu; Liu, Jiayu; Huang, Qi; Guo, Jingkai; Nguyen, Thao D.; Gracias, David H.; Schulman, Rebecca

    2017-09-01

    Shape-changing hydrogels that can bend, twist, or actuate in response to external stimuli are critical to soft robots, programmable matter, and smart medicine. Shape change in hydrogels has been induced by global cues, including temperature, light, or pH. Here we demonstrate that specific DNA molecules can induce 100-fold volumetric hydrogel expansion by successive extension of cross-links. We photopattern up to centimeter-sized gels containing multiple domains that undergo different shape changes in response to different DNA sequences. Experiments and simulations suggest a simple design rule for controlled shape change. Because DNA molecules can be coupled to molecular sensors, amplifiers, and logic circuits, this strategy introduces the possibility of building soft devices that respond to diverse biochemical inputs and autonomously implement chemical control programs.

  20. 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.

  1. Electronic phase separation and high temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-01-11

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

  2. 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.)

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

    Science.gov (United States)

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

    2017-08-14

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

  4. 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 ...

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

    Indian Academy of Sciences (India)

    Samadhan Krushna Phuge

    2017-06-20

    Jun 20, 2017 ... temperatures on gonadal development, sex ratio and metamorphosis was studied in the Indian skipper frog, Euphlyctis ..... Table 1. Effect of rearing water temperature on gonadal differentiation and sex ratio of Euphlyctis cyanophlyctis .... tures (28, 30 and 32°C) induced female to male sex reversal.

  6. Problem aspects of high temperature referral metrology

    Science.gov (United States)

    Khodunkov, V. P.

    2017-11-01

    The main problematic aspects of the reproduction and transmission of a unit of temperature by a direct method are considered. The methodology and hardware for its implementation are considered. An estimate of the expected uncertainty in the measurement of the thermodynamic temperature is given.

  7. Shape recovery and irrecoverable strain control in polyurethane shape-memory polymer

    Directory of Open Access Journals (Sweden)

    Hisaaki Tobushi et al

    2008-01-01

    Full Text Available In shape-memory polymers, large strain can be fixed at a low temperature and thereafter recovered at a high temperature. If the shape-memory polymer is held at a high temperature for a long time, the irrecoverable strain can attain a new intermediate shape between the shape under the maximum stress and the primary shape. Irrecoverable strain control can be applied to the fabrication of a shape-memory polymer element with a complex shape in a simple method. In the present study, the influence of the strain-holding conditions on the shape recovery and the irrecoverable strain control in polyurethane shape-memory polymer is investigated by tension test of a film and three-point bending test of a sheet. The higher the shape-holding temperature and the longer the shape-holding time, the higher the irrecoverable strain rate. The equation that expresses the characteristics of the irrecoverable strain control is formulated.

  8. HIGH TEMPERATURE HIGH PRESSURE THERMODYNAMIC MEASUREMENTS FOR COAL MODEL COMPOUNDS

    Energy Technology Data Exchange (ETDEWEB)

    Vinayak N. Kabadi

    2000-05-01

    The Vapor Liquid Equilibrium measurement setup of this work was first established several years ago. It is a flow type high temperature high pressure apparatus which was designed to operate below 500 C temperature and 2000 psia pressure. Compared with the static method, this method has three major advantages: the first is that large quantity of sample can be obtained from the system without disturbing the equilibrium state which was established before; the second is that the residence time of the sample in the equilibrium cell is greatly reduced, thus decomposition or contamination of the sample can be effectively prevented; the third is that the flow system allows the sample to degas as it heats up since any non condensable gas will exit in the vapor stream, accumulate in the vapor condenser, and not be recirculated. The first few runs were made with Quinoline-Tetralin system, the results were fairly in agreement with the literature data . The former graduate student Amad used the same apparatus acquired the Benzene-Ethylbenzene system VLE data. This work used basically the same setup (several modifications had been made) to get the VLE data of Ethylbenzene-Quinoline system.

  9. 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.

  10. Vortices in high-performance high-temperature superconductors

    Science.gov (United States)

    Kwok, Wai-Kwong; Welp, Ulrich; Glatz, Andreas; Koshelev, Alexei E.; Kihlstrom, Karen J.; Crabtree, George W.

    2016-11-01

    The behavior of vortex matter in high-temperature superconductors (HTS) controls the entire electromagnetic response of the material, including its current carrying capacity. Here, we review the basic concepts of vortex pinning and its application to a complex mixed pinning landscape to enhance the critical current and to reduce its anisotropy. We focus on recent scientific advances that have resulted in large enhancements of the in-field critical current in state-of-the-art second generation (2G) YBCO coated conductors and on the prospect of an isotropic, high-critical current superconductor in the iron-based superconductors. Lastly, we discuss an emerging new paradigm of critical current by design—a drive to achieve a quantitative correlation between the observed critical current density and mesoscale mixed pinning landscapes by using realistic input parameters in an innovative and powerful large-scale time dependent Ginzburg-Landau approach to simulating vortex dynamics.

  11. Flexible electrical conductors for high-temperature switchgear

    Science.gov (United States)

    Koutnik, E. A.; Mueller, L. A.; Snider, W. E.

    1970-01-01

    Arch-shaped conductors fabricated from flat strips of beryllium oxide dispersion-strengthened copper alloy serve as flexible electrical connectors capable of operating in 1000 deg F temperature range, under vacuum conditions for periods of 10,000 hours or more without failure.

  12. High-resolution wavefront shaping with a photonic crystal fiber for multimode fiber imaging.

    Science.gov (United States)

    Amitonova, Lyubov V; Descloux, Adrien; Petschulat, Joerg; Frosz, Michael H; Ahmed, Goran; Babic, Fehim; Jiang, Xin; Mosk, Allard P; Russell, Philip St J; Pinkse, Pepijn W H

    2016-02-01

    We demonstrate that a high-numerical-aperture photonic crystal fiber allows lensless focusing at an unparalleled resolution by complex wavefront shaping. This paves the way toward high-resolution imaging exceeding the capabilities of imaging with multi-core single-mode optical fibers. We analyze the beam waist and power in the focal spot on the fiber output using different types of fibers and different wavefront shaping approaches. We show that the complex wavefront shaping technique, together with a properly designed multimode photonic crystal fiber, enables us to create a tightly focused spot on the desired position on the fiber output facet with a subwavelength beam waist.

  13. The study of some physical properties of high temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Ismail, Atif Mahmoud

    2008-07-01

    The phenomenon of superconductivity, the discovery of high temperature superconductivity in the Cuprates and the properties of these materials is described in the introductory chapter. It also includes a discussion of the pseudogap, which has remained a mystery as has the high transition temperature. Possible applications of high temperature superconductivity are reviewed before the theories by Bardeen, Cooper, and Schrieffer (BCS) and Ginzburg and Landau are briefly sketched. The last section gives excerpts of the by now vast literature on this subject, focussing on the role impurities play in this context. The second chapter develops the mathematical tools and the theoretical background for the description of many-body systems. Various Green's functions are introduced which are then used to describe scattering of quasiparticles off defects of arbitrary strength. They are also required to calculate the a.c. conductivity, for which an expression is derived using linear response theory. The convergence problems one encounters when actually calculating the conductivity are briefly discussed. Detailed calculations for the normal state are presented in the third chapter and in the appendix. The third Chapter begins with a detailed presentation of the tight binding model for the energy dispersion because this model appears to give a more accurate description of the electronic properties of high temperature superconductors than the nearly free electron model. The shape of the two-dimensional Fermi surface is calculated and displayed as function of band filling and the next-nearest neighbor hopping integral B, assuming a rigid band. B plays an important role in the formation of so-called hot spots. The quasiparticle density of states and its Hilbert transform F({omega}) are solved by means of complete elliptic integrals formalism. These results are used to obtain impurity bound states. A simple model for the superconductivity in the cuprate materials is developed on

  14. Spectral emissivity of candidate alloys for very high temperature reactors in high temperature air environment

    Energy Technology Data Exchange (ETDEWEB)

    Cao, G., E-mail: gcao@wisc.edu; Weber, S.J.; Martin, S.O.; Sridharan, K.; Anderson, M.H.; Allen, T.R.

    2013-10-15

    Emissivity measurements for candidate alloys for very high temperature reactors were carried out in a custom-built experimental facility, capable of both efficient and reliable measurements of spectral emissivities of multiple samples at high temperatures. The alloys studied include 304 and 316 austenitic stainless steels, Alloy 617, and SA508 ferritic steel. The oxidation of alloys plays an important role in dictating emissivity values. The higher chromium content of 304 and 316 austenitic stainless steels, and Alloy 617 results in an oxide layer only of sub-micron thickness even at 700 °C and consequently the emissivity of these alloys remains low. In contrast, the low alloy SA508 ferritic steel which contains no chromium develops a thicker oxide layer, and consequently exhibits higher emissivity values.

  15. Spectral emissivity of candidate alloys for very high temperature reactors in high temperature air environment

    Science.gov (United States)

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

    2013-10-01

    Emissivity measurements for candidate alloys for very high temperature reactors were carried out in a custom-built experimental facility, capable of both efficient and reliable measurements of spectral emissivities of multiple samples at high temperatures. The alloys studied include 304 and 316 austenitic stainless steels, Alloy 617, and SA508 ferritic steel. The oxidation of alloys plays an important role in dictating emissivity values. The higher chromium content of 304 and 316 austenitic stainless steels, and Alloy 617 results in an oxide layer only of sub-micron thickness even at 700 °C and consequently the emissivity of these alloys remains low. In contrast, the low alloy SA508 ferritic steel which contains no chromium develops a thicker oxide layer, and consequently exhibits higher emissivity values.

  16. Influence of deformation temperature on structural variation and shape-memory effect of a thermoplastic semi-crystalline multiblock copolymer

    Directory of Open Access Journals (Sweden)

    W. Yan

    2015-07-01

    Full Text Available A multiblock copolymer termed as PCL-PIBMD, consisting of crystallizable poly(ε-caprolactone (PCL segments and crystallizable poly(3S-isobutyl-morpholine-2,5-dione (PIBMD segments, has been reported as a material showing a thermally-induced shape-memory effect. While PIBMD crystalline domains act as netpoints to determine the permanent shape, both PCL crystalline domains and PIBMD amorphous domains, which have similar transition temperatures (Ttrans can act as switching domains. In this work, the influence of the deformation temperature (Tdeform = 50 or 20°C, which was above or below Ttrans, on the structural changes of PCL-PIBMD during uniaxial deformation and the shapememory properties were investigated. Furthermore, the relative contribution of crystalline PCL and PIBMD amorphous phases to the fixation of the temporary shape were distinguished by a toluene vapor treatment approach. The results indicated that at 50°C, both PCL and PIBMD amorphous phases can be orientated during deformation, resulting in thermallyinduced crystals of PCL domains and joint contribution to the switching domains. In contrast at 20°C, the temporary shape was mainly fixed by PCL crystals generated via strain-induced crystallization.

  17. 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.

  18. 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.

  19. 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...

  20. Extreme Environment High Temperature Communication Systems Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The purpose of this project is to develop and demonstrate a communications system capable of operation at extreme temperatures and pressures in hostile and corrosive...

  1. High Temperature Characterization of Ceramic Pressure Sensors

    National Research Council Canada - National Science Library

    Fonseca, Michael A; English, Jennifer M; Von Arx, Martin; Allen, Mark G

    2001-01-01

    This work reports functional wireless ceramic micromachined pressure sensors operating at 450 C, with demonstrated materials and readout capability indicating potential extension to temperatures in excess of 600 C...

  2. High Temperature Acoustic Noise Reduction Materials Project

    Data.gov (United States)

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

  3. 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. 

  4. Corrosion behavior of shape memory, superelastic, and nonsuperelastic nickel-titanium-based orthodontic wires at various temperatures.

    Science.gov (United States)

    Pun, Deo K; Berzins, David W

    2008-02-01

    Nickel-titanium orthodontic wires have various temperature-dependent phases. The purpose of this study was to investigate temperature-dependent corrosion characteristics of shape memory, superelastic, and nonsuperelastic orthodontic wires. Four orthodontic wires were investigated: 27 and 40 degrees C copper Ni-Ti (superelastic and shape memory, respectively), superelastic Ni-Ti, and nonsuperelastic Nitinol Classic. Differential scanning calorimetry (DSC) was used to confirm phase/temperature behavior of the wires. Sectioned halves of as-received archwires were assessed electrochemically in artificial saliva at 5, 24, 37, and 45 degrees C. Open circuit potential (OCP) was monitored for 2h followed by polarization resistance and cyclic polarization tests. DSC results showed Nitinol was primarily martensitic-stable whereas NiTi, 27 degrees C CuNiTi, and 40 degrees C CuNiTi possessed austenite-finish temperatures of approximately 19, 21, and 38 degrees C. The OCP of the CuNiTi wires was significantly greater than NiTi and Nitinol but no apparent trend in values was apparent with regard to temperature or phases present. Corrosion current density (i(corr)) increased with temperature for all wires, but not all were equally influenced. The two lowest austenite-finish temperature wires (27 degrees C CuNiTi and NiTi) approximately tripled in i(corr) from 37 to 45 degrees C. Greater incidence of pitting was observed in the CuNiTi wires. This study showed the corrosion rate of various nickel-titanium wires increase with temperature and different phases present may influence corrosion rate trends.

  5. Stress- and Magnetic Field-Induced Martensitic Transformation at Cryogenic Temperatures in Fe-Mn-Al-Ni Shape Memory Alloys

    Science.gov (United States)

    Xia, Ji; Xu, Xiao; Miyake, Atsushi; Kimura, Yuta; Omori, Toshihiro; Tokunaga, Masashi; Kainuma, Ryosuke

    2017-11-01

    Stress-induced and magnetic-field-induced martensitic transformation behaviors at low temperatures were investigated for Fe-Mn-Al-Ni alloys. The magnetic-field-induced reverse martensitic transformation was directly observed by in situ optical microscopy. Magnetization measurements under pulsed magnetic fields up to 50 T were carried out at temperatures between 4.2 and 125 K on a single-crystal sample; full magnetic-field-induced reverse martensitic transformation was confirmed at all tested temperatures. Compression tests from 10 to 100 K were conducted on a single-crystal sample; full shape recovery was obtained at all tested temperatures. It was found that the temperature dependence of both the critical stress and critical magnetic field is small and that the transformation hysteresis is less sensitive to temperature even at cryogenic temperatures. The temperature dependence of entropy change during martensitic transformation up to 100 K was then derived using the Clausius-Clapeyron relation with critical stresses and magnetic fields.

  6. Stress- and Magnetic Field-Induced Martensitic Transformation at Cryogenic Temperatures in Fe-Mn-Al-Ni Shape Memory Alloys

    Science.gov (United States)

    Xia, Ji; Xu, Xiao; Miyake, Atsushi; Kimura, Yuta; Omori, Toshihiro; Tokunaga, Masashi; Kainuma, Ryosuke

    2017-12-01

    Stress-induced and magnetic-field-induced martensitic transformation behaviors at low temperatures were investigated for Fe-Mn-Al-Ni alloys. The magnetic-field-induced reverse martensitic transformation was directly observed by in situ optical microscopy. Magnetization measurements under pulsed magnetic fields up to 50 T were carried out at temperatures between 4.2 and 125 K on a single-crystal sample; full magnetic-field-induced reverse martensitic transformation was confirmed at all tested temperatures. Compression tests from 10 to 100 K were conducted on a single-crystal sample; full shape recovery was obtained at all tested temperatures. It was found that the temperature dependence of both the critical stress and critical magnetic field is small and that the transformation hysteresis is less sensitive to temperature even at cryogenic temperatures. The temperature dependence of entropy change during martensitic transformation up to 100 K was then derived using the Clausius-Clapeyron relation with critical stresses and magnetic fields.

  7. 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.

  8. Shape stabilised phase change materials (SSPCMs): High density polyethylene and hydrocarbon waxes

    Energy Technology Data Exchange (ETDEWEB)

    Mu, Mulan, E-mail: mmu01@qub.ac.uk, E-mail: m.basheer@qub.ac.uk; Basheer, P. A. M., E-mail: mmu01@qub.ac.uk, E-mail: m.basheer@qub.ac.uk [School of Planning, Architecture and Civil Engineering, Queen' s University Belfast, BT9 5AG (United Kingdom); Bai, Yun, E-mail: yun.bai@ucl.ac.uk [Department of Civil, Environmental and Geomatic Engineering, University College London, WC1E 6BT (United Kingdom); McNally, Tony, E-mail: t.mcnally@warwick.ac.uk [WMG, University of Warwick, CV4 7AL (United Kingdom)

    2014-05-15

    Shape stabilised phase change materials (SSPCMs) based on high density polyethylene (HDPE) with high (HPW, T{sub m}=56-58 °C) and low (L-PW, T{sub m}=18-23 °C) melting point waxes were prepared by melt-mixing in a twin-screw extruder and their potential in latent heat thermal energy storage (LHTES) applications for housing assessed. The structure and morphology of these blends were investigated by scanning electron microscopy (SEM). Both H-PW and L-PW were uniformly distributed throughout the HDPE matrix. The melting point and latent heat of the SSPCMs were determined by differential scanning calorimetry (DSC). The results demonstrated that both H-PW and L-PW have a plasticisation effect on the HDPE matrix. The tensile and flexural properties of the samples were measured at room temperature (RT, 20±2 °C) and 70 °C, respectively. All mechanical properties of HDPE/H-PW and HDPE/L-PW blends decreased from RT to 70 °C. In all instances at RT, modulus and stress, irrespective of the mode of deformation was greater for the HDPE/H-PW blends. However, at 70 °C, there was no significant difference in mechanical properties between the HDPE/H-PW and HDPE/L-PW blends.

  9. The influence of shape-holding conditions on shape recovery of polyurethane-shape memory polymer foams

    Science.gov (United States)

    Tobushi, H.; Matsui, R.; Hayashi, S.; Shimada, D.

    2004-08-01

    The thermomechanical properties of polyurethane-shape memory polymer (SMP) foams and the influence of shape-holding conditions on shape recovery were investigated experimentally. The results obtained can be summarized as follows. (1) By cooling the foam down to below the glass transition temperature Tg after compressive deformation above Tg, stress decreases and the deformed shape is fixed. By heating the shape-fixed foam up to above Tg under no load, the original shape is recovered. (2) The shape deformed above Tg is maintained for six months under no load at Tg- 60 K without depending on the maximum strain, and the original shape is recovered by heating thereafter. (3) If the deformed shape is held at high temperature, the original shape is not recovered. (4) The ratio of shape irrecovery increases in proportion to the holding strain, holding temperature and holding time.

  10. Design of High Field Solenoids made of High Temperature Superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Bartalesi, Antonio; /Pisa U.

    2010-12-01

    This thesis starts from the analytical mechanical analysis of a superconducting solenoid, loaded by self generated Lorentz forces. Also, a finite element model is proposed and verified with the analytical results. To study the anisotropic behavior of a coil made by layers of superconductor and insulation, a finite element meso-mechanic model is proposed and designed. The resulting material properties are then used in the main solenoid analysis. In parallel, design work is performed as well: an existing Insert Test Facility (ITF) is adapted and structurally verified to support a coil made of YBa{sub 2}Cu{sub 3}O{sub 7}, a High Temperature Superconductor (HTS). Finally, a technological winding process was proposed and the required tooling is designed.

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

    Indian Academy of Sciences (India)

    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 strength of the composite of all compositions increased at 1200 and 1300°C because of oxidation of Si3N4 phase and blunting crack front.

  12. 46 CFR 56.60-5 - Steel (High temperature applications).

    Science.gov (United States)

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Steel (High temperature applications). 56.60-5 Section... SYSTEMS AND APPURTENANCES Materials § 56.60-5 Steel (High temperature applications). (a) (Reproduces 124.2.A.) Upon prolonged exposure to temperatures above 775 °F (412 °C), the carbide phase of plain carbon...

  13. 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, ...

  14. Pargasite at high pressure and temperature

    Science.gov (United States)

    Comboni, Davide; Lotti, Paolo; Gatta, G. Diego; Merlini, Marco; Liermann, Hanns-Peter; Frost, Daniel J.

    2017-08-01

    The P-T phase stability field, the thermoelastic behavior and the P-induced deformation mechanisms at the atomic scale of pargasite crystals, from the "phlogopite peridotite unit" of the Finero mafic-ultramafic complex (Ivrea-Verbano Formation, Italy), have been investigated by a series of in situ experiments: (a) at high pressure (up to 20.1 GPa), by single-crystal synchrotron X-ray diffraction with a diamond anvil cell, (b) at high temperature (up to 823 K), by powder synchrotron X-ray diffraction using a hot air blower device, and (c) at simultaneous HP-HT conditions, by single-crystal synchrotron X-ray diffraction with a resistive-heated diamond anvil cell (P max = 16.5 GPa, T max = 1200 K). No phase transition has been observed within the P-T range investigated. At ambient T, the refined compressional parameters, calculated by fitting a second-order Birch-Murnaghan Equation of State (BM-EoS), are: V 0 = 915.2(8) Å3 and K P0,T0 = 95(2) GPa (β P0,T0 = 0.0121(2) GPa-1) for the unit-cell volume; a 0 = 9.909(4) Å and K(a) P0,T0 = 76(2) GPa for the a-axis; b 0 = 18.066(7) Å and K(b) P0,T0 = 111(2) GPa for the b-axis; c 0 = 5.299(5) Å and K(c) P0,T0 = 122(12) GPa for the c-axis [K(c) P0,T0 K(b) P0,T0 > K(a) P0,T0]. The high-pressure structure refinements (at ambient T) show a moderate contraction of the TO4 double chain and a decrease of its bending in response to the hydrostatic compression, along with a pronounced compressibility of the A- and M(4)-polyhedra [K P0, T0(A) = 38(2) GPa, K P0, T0(M4) = 79(5) GPa] if compared to the M(1)-, M(2)-, M(3)-octahedra [K P0, T0(M1,2,3) ≤ 120 GPa] and to the rigid tetrahedra [K P0, T0(T1,T2) 300 GPa]. The thermal behavior, at ambient pressure up to 823 K, was modelled with Berman's formalism, which gives: V 0 = 909.1(2) Å3, α0 = 2.7(2)·10-5 K-1 and α1 = 1.4(6)·10-9 K-2 [with α0(a) = 0.47(6)·10-5 K-1, α0(b) = 1.07(4)·10-5 K-1, and α0(c) = 0.97(7)·10-5 K-1]. The petrological implications for the experimental

  15. Implementation Challenges for Ceramic Matrix Composites in High Temperature Applications

    Science.gov (United States)

    Singh, Mrityunjay

    2004-01-01

    Ceramic matrix composites are leading candidate materials for a number of applications in aeronautics, space, energy, electronics, nuclear, and transportation industries. In the aeronautics and space exploration systems, these materials are being considered for applications in hot sections of jet engines such as the combustor liner, nozzle components, nose cones, leading edges of reentry vehicles and space propulsion components. Applications in the energy and environmental industries include radiant heater tubes, heat exchangers, heat recuperators, gas and diesel particulate filters (DPFs), and components for land based turbines for power generation. These materials are also being considered for use in the first wall and blanket components of fusion reactors. There are a number of critical issues and challenges related to successful implementation of composite materials. Fabrication of net and complex shape components with high density and tailorable matrix properties is quite expensive, and even then various desirable properties are not achievable. In this presentation, microstructure and thermomechanical properties of composites fabricated by two techniques (chemical vapor infiltration and melt infiltration), will be presented. In addition, critical need for robust joining and assembly technologies in successful implementation of these systems will be discussed. Other implementation issues will be discussed along with advantages and benefits of using these materials for various components in high temperature applications.

  16. Transport Processes in High Temperature QCD Plasmas

    Science.gov (United States)

    Hong, Juhee

    The transport properties of high temperature QCD plasmas can be described by kinetic theory based on the Boltzmann equation. At a leading-log approximation, the Boltzmann equation is reformulated as a Fokker-Planck equation. First, we compute the spectral densities of Tµν and Jµ by perturbing the system with weak gravitational and electromagnetic fields. The spectral densities exhibit a smooth transition from free-streaming quasi-particles to hydrodynamics. This transition is analyzed with hydrodynamics and diffusion equation up to second order. We determine all of the first and second order transport coefficients which characterize the linear response in the hydrodynamic regime. Second, we simulate the wake of a heavy quark moving through the plasmas. At long distances, the energy density and flux distributions show sound waves and a diffusion wake. The kinetic theory calculations based on the Boltzmann equation at weak coupling are compared to the strong coupling results given by the AdS/CFT correspondence. By using the hard-thermal-loop effective theory, we determine the photon emission rate at next-to-leading order (NLO), i.e., at order g2mD /T. There are three mechanisms which contribute to the leading-order photon emission: (2 ↔ 2) elastic scatterings, (1 ↔ 2) collinear bremsstrahlung, and (1 ↔ 1) quark-photon conversion due to soft fermion exchange. At NLO, these three mechanisms are not completely independent. When the transverse momentum between quark and photon becomes soft, the Compton scattering with a soft gluon reduces to wide-angle bremsstrahlung. Similarly, bremsstrahlung reduces to the quark-photon conversion process when the photon carries most of the incoming momentum. Therefore, the rates should be matched to determine the wide-angle NLO correction. Collinear bremsstrahlung can be accounted for by solving an integral equation which corresponds to summing ladder diagrams. With O(g) corrections in the collision kernel and the asymptotic

  17. Magnesium Diecasting Alloys for High Temperature Applications

    Science.gov (United States)

    Pekguleryuz, Mihriban O.; Kaya, A. Arslan

    New growth area for automotive use of magnesium is powertrain applications such as the transmission case and engine block. These applications see service conditions in the temperature range of 150-200C under 50-70 MPa of tensile and compressive loads. In addition, metallurgical stability, fatigue resistance, corrosion resistance and castability requirements need to be met. A decade of research and development has resulted in a number of creep- resistant magnesium alloys that are potential candidates for elevated-temperature automotive applications. These alloys are mostly based on rare-earth and alkaline earth element additions to magnesium. This paper gives an overview of the various magnesium alloy systems for use in elevated-temperature applications.

  18. 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-catalysts...... were tested in order to reduce the oxygen and hydrogen overpotentials. Current densities of 1.1 A cm-2 and 2.3 A cm-2 have been measured at a cell voltage of 1.5 V and 1.75 V, respectively, without using expensive noble metal catalysts. Electrical efficiencies of almost 99 % at 1.1 A cm-2 and 85 % at 2...... against conventional technologies for hydrogen production, such as natural gas reforming, the production and investment costs have to be reduced. A reduction of the investment costs may be achieved by increasing the operational pressure and temperature of the electrolyzer, as this will result in: 1...

  19. 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

  20. High incubation temperatures enhance mitochondrial energy metabolism in reptile embryos.

    Science.gov (United States)

    Sun, Bao-Jun; Li, Teng; Gao, Jing; Ma, Liang; Du, Wei-Guo

    2015-03-09

    Developmental rate increases exponentially with increasing temperature in ectothermic animals, but the biochemical basis underlying this thermal dependence is largely unexplored. We measured mitochondrial respiration and metabolic enzyme activities of turtle embryos (Pelodiscus sinensis) incubated at different temperatures to identify the metabolic basis of the rapid development occurring at high temperatures in reptile embryos. Developmental rate increased with increasing incubation temperatures in the embryos of P. sinensis. Correspondingly, in addition to the thermal dependence of mitochondrial respiration and metabolic enzyme activities, high-temperature incubation further enhanced mitochondrial respiration and COX activities in the embryos. This suggests that embryos may adjust mitochondrial respiration and metabolic enzyme activities in response to developmental temperature to achieve high developmental rates at high temperatures. Our study highlights the importance of biochemical investigations in understanding the proximate mechanisms by which temperature affects embryonic development.

  1. Study of hot air generator with quasi-uniform temperature using concentrated solar radiation: Influence of the shape parameters

    Energy Technology Data Exchange (ETDEWEB)

    Ould Mohamed Mahmoud, Ahmedou [Faculte des Sciences et Techniques de Nouakchott, Departement de Physique, BP 5026, Nouakchott (Mauritania); Zinoubi, Jamil [Institut preparatoire aux etudes d' ingenieurs de Nabeul, Merazka, Nabeul (Tunisia); Ben Maad, Rejeb [Faculte des Sciences de Tunis, Laboratoire d' Energetique et des Transferts Thermique et Massique, El Manar, Tunis (Tunisia). Departement de Physique

    2007-02-15

    The non-uniformity of the air temperatures and the slow flow rate at the plane collector exit constitute the main cause of the limitations of the solar drying systems. In order to obtain an uniform and a variable flow rate for different uses, a hot air generator using concentrated solar radiation is proposed. To improve the thermal efficiency of the generator, a study of the influence of different shape parameters is realized. The generator is simulated in the laboratory while investigating the flow induced by a circular disc heated uniformly by Joule effect at constant temperature. This disc is placed at the entrance of an open ended vertical cylinder of a larger diameter. Thermal radiation emitted by the hot disc heats the cylinder wall. The heating of the fluid at the cylinder-inlet generates a thermosiphon flow around the one created by the hot disc. The comparison of the velocity and the temperature profiles of the resulting flow permits to determine the influence of the cylinder height, the vertical source-cylinder spacing and the radius ratio, on the resulting flow at the system exit. Thus, a judicious choice of the shape parameters entails an improvement of the flow rate as well as the thermal flux absorbed by the air and a good homogenization of the air temperature at the generator exit. (author)

  2. Joining and Assembly of Silicon Carbide-based Advanced Ceramics and Composites for High Temperature Applications

    Science.gov (United States)

    Singh, M.

    2004-01-01

    Silicon carbide based advanced ceramics and fiber reinforced composites are under active consideration for use in wide variety of high temperature applications within the aeronautics, space transportation, energy, and nuclear industries. The engineering designs of ceramic and composite component require fabrication and manufacturing of large and complex shaped parts of various thicknesses. In many instances, it is more economical to build up complex shapes by joining simple geometrical shapes. In addition these components have to be joined or assembled with metallic sub-components. Thus, joining and attachment have been recognized as enabling technologies for successful utilization of ceramic components in various demanding applications. In this presentation, various challenges and opportunities in design, fabrication, and testing o high temperature joints in ceramic matrix composites will be presented. Silicon carbide based advanced ceramics (CVD and hot pressed), and C/SiC and SiC/SiC composites, in different shapes and sizes, have been joined using an affordable, robust ceramic joining technology (ARCJoinT). Microstructure and high temperature mechanical properties of joints in silicon carbide ceramics and CVI and melt infiltrated SiC matrix composites will,be reported. Various joint design philosophies and design issues in joining of ceramics and composites well be discussed.

  3. Wall temperature measurements at elevated pressures and high temperatures in sooting flames in a gas turbine model combustor

    Science.gov (United States)

    Nau, Patrick; Yin, Zhiyao; Geigle, Klaus Peter; Meier, Wolfgang

    2017-12-01

    Wall temperatures were measured with thermographic phosphors on the quartz walls of a model combustor in ethylene/air swirl flames at 3 bar. Three operating conditions were investigated with different stoichiometries and with or without additional injection of oxidation air downstream of the primary combustion zone. YAG:Eu and YAG:Dy were used to cover a total temperature range of 1000-1800 K. Measurements were challenging due to the high thermal background from soot and window degradation at high temperatures. The heat flux through the windows was estimated from the temperature gradient between the in- and outside of the windows. Differences in temperature and heat flux density profiles for the investigated cases can be explained very well with the previously measured differences in flame temperatures and flame shapes. The heat loss relative to thermal load is quite similar for all investigated flames (15-16%). The results complement previous measurements in these flames to investigate soot formation and oxidation. It is expected, that the data set is a valuable input for numerical simulations of these flames.

  4. 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.

  5. Maintenance in Service of High Temperature Parts

    Science.gov (United States)

    1982-01-01

    program activities. io4 6-1 DEFECTS AND THEIR EFFECT ON THE BEHAVIOUR OF GAS TIURBNE DISCS Robert H Jeal Head of Materials Engineering Rolls-Royce Limited...temperature sulphidatien and hot forrosal. m 5.• ACKNOWLEDGEMENT The author wishes to thank N. Swindells of the University of Livernool for his efforts in

  6. Micromechanics of high temperature hydrogen attack

    NARCIS (Netherlands)

    Schlögl, Sabine M.; Giessen, Erik van der

    1999-01-01

    Hydrogen attack is a material degradation process that occurs at elevated temperatures in hydrogen-rich environments, such as found in petro-chemical installations. Weldments in components such as reactor vessels are particularly susceptible to hydrogen attack. This paper discusses a multi-scale

  7. Do shape invariant solitons in highly nonlocal nematic liquid crystals really exist?

    CERN Document Server

    Petrovic, Milan S; Aleksic, Najdan B; Belic, Milivoj R

    2011-01-01

    We question physical existence of shape invariant solitons in three dimensional nematic liquid crystals. Using modified Petviashvili's method for finding eigenvalues and eigenfunctions, we determine shape invariant solitons in a realistic physical model that includes the highly nonlocal nature of the liquid crystal system. We check the stability of such solutions by propagating them for long distances. We establish that any noise added to the medium or to the fundamental solitons induces them to breathe, rendering them practically unobservable.

  8. 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

  9. Ceramic membranes for high temperature hydrogen separation

    Energy Technology Data Exchange (ETDEWEB)

    Adcock, K.D.; Fain, D.E.; James, D.L.; Powell, L.E.; Raj, T.; Roettger, G.E.; Sutton, T.G. [East Tennessee Technology Park, Oak Ridge, TN (United States)

    1997-12-01

    The separative performance of the authors` ceramic membranes has been determined in the past using a permeance test system that measured flows of pure gases through a membrane at temperatures up to 275 C. From these data, the separation factor was determined for a particular gas pair from the ratio of the pure gas specific flows. An important project goal this year has been to build a Mixed Gas Separation System (MGSS) for measuring the separation efficiencies of membranes at higher temperatures and using mixed gases. The MGSS test system has been built, and initial operation has been achieved. The MGSS is capable of measuring the separation efficiency of membranes at temperatures up to 600 C and pressures up to 100 psi using a binary gas mixture such as hydrogen/methane. The mixed gas is fed into a tubular membrane at pressures up to 100 psi, and the membrane separates the feed gas mixture into a permeate stream and a raffinate stream. The test membrane is sealed in a stainless steel holder that is mounted in a split tube furnace to permit membrane separations to be evaluated at temperatures up to 600 C. The compositions of the three gas streams are measured by a gas chromatograph equipped with thermal conductivity detectors. The test system also measures the temperatures and pressures of all three gas streams as well as the flow rate of the feed stream. These data taken over a range of flows and pressures permit the separation efficiency to be determined as a function of the operating conditions. A mathematical model of the separation has been developed that permits the data to be reduced and the separation factor for the membrane to be determined.

  10. 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.

  11. GRCop-84: A High Temperature Copper-based Alloy For High Heat Flux Applications

    Science.gov (United States)

    Ellis, David L.

    2005-01-01

    While designed for rocket engine main combustion chamber liners, GRCop-84 (Cu-8 at.% Cr-4 at.% Nb) offers potential for high heat flux applications in industrial applications requiring a temperature capability up to approximately 700 C (1292 F). GRCop-84 is a copper-based alloy with excellent elevated temperature strength, good creep resistance, long LCF lives and enhanced oxidation resistance. It also has a lower thermal expansion than copper and many other low alloy copper-based alloys. GRCop-84 can be manufactured into a variety of shapes such as tubing, bar, plate and sheet using standard production techniques and requires no special production techniques. GRCop-84 forms well, so conventional fabrication methods including stamping and bending can be used. GRCop-84 has demonstrated an ability to be friction stir welded, brazed, inertia welded, diffusion bonded and electron beam welded for joining to itself and other materials. Potential applications include plastic injection molds, resistance welding electrodes and holders, permanent metal casting molds, vacuum plasma spray nozzles and high temperature heat exchanger applications.

  12. Effect of strain wave shape on low-cycle fatigue crack propagation of SUS 304 stainless steel at elevated temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Okazaki, M.; Hattori, I.; Koizwmi, T.; Shiraiwa, F.

    1983-08-01

    Effect of strain wave shape on strain-controlled low-cycle fatigue crack propagation of SUS 304 stainless steel was investigated at 600 and 700/sup 0/C. It was found that the rate of crack propagation in a cycle-dependent region was successfully correlated with the range of cyclic J-integral, ..delta..J /SUB f/, regardless of the strain wave shape, frequency, and test temperature. It was also shown that the rate of crack propagation gradually increased from cycle-dependent curve to time-dependent one with decreasing frequency and slow-fast strain wave shape, and that one of the factors governing the rate of crack propagation in such a region was the ratio of the range of creep J-integral to that of total J-integral, ..delta..J /SUB c/ /..delta..J /SUB T/. Based on the results thus obtained, an interaction damage rule proposed semi-empirically was interpreted, with regard to crack propagation. Furthermore, fatigue crack initiation mechanism in slow-fast strain wave shape was studied, and it was shown that grain boundary sliding took an important role in it.

  13. Aircraft Reconstruction in High Resolution SAR Images Using Deep Shape Prior

    Directory of Open Access Journals (Sweden)

    Dou Fangzheng

    2017-10-01

    Full Text Available Object reconstruction is of vital importance in Synthetic Aperture Radar (SAR image analysis. In this paper, we propose a novel method based on shape prior to reconstruct aircraft in high resolution SAR images. The method mainly contains two stages. In the shape prior modeling stage, a generative deep learning method is used to model deep shape priors; a novel framework is then proposed in the reconstruction stage, which integrates the shape priors in the process of reconstruction. Specifically, to address the issue of object rotation, a novel pose estimation method is proposed to obtain candidate poses, which avoids making an exhaustive search for each pose. In addition, an energy function combining a scattering region term and a shape prior term is proposed; this is optimized via an iterative optimization algorithm to achieve the goal of object reconstruction. To the best of our knowledge, this is the first attempt made to reconstruct objects with complex shapes in SAR images using deep shape priors. Experiments are conducted on the dataset acquired by TerraSAR-X and results demonstrate the accuracy and robustness of the proposed method.

  14. Influence of temperature on the rhombic shape of paracetamol molecular crystals

    Science.gov (United States)

    Belyaev, A. P.; Rubets, V. P.; Antipov, V. V.

    2017-04-01

    The method of differential scanning ellipsometry has been used to study the influence of heating on the rhombic shape of paracetamol molecular crystals. Rhombic molecular paracetamol crystals have been synthesized in vacuum from the vapor phase of paracetamol as a result of complex transformation, which includes a second-order transition that gives rise to a pretransition phase. It has been found that these crystals contain monoclinic nuclei, which favor the form I-to-form II polymorphic transformation during heating.

  15. SmartGrain: high-throughput phenotyping software for measuring seed shape through image analysis.

    Science.gov (United States)

    Tanabata, Takanari; Shibaya, Taeko; Hori, Kiyosumi; Ebana, Kaworu; Yano, Masahiro

    2012-12-01

    Seed shape and size are among the most important agronomic traits because they affect yield and market price. To obtain accurate seed size data, a large number of measurements are needed because there is little difference in size among seeds from one plant. To promote genetic analysis and selection for seed shape in plant breeding, efficient, reliable, high-throughput seed phenotyping methods are required. We developed SmartGrain software for high-throughput measurement of seed shape. This software uses a new image analysis method to reduce the time taken in the preparation of seeds and in image capture. Outlines of seeds are automatically recognized from digital images, and several shape parameters, such as seed length, width, area, and perimeter length, are calculated. To validate the software, we performed a quantitative trait locus (QTL) analysis for rice (Oryza sativa) seed shape using backcrossed inbred lines derived from a cross between japonica cultivars Koshihikari and Nipponbare, which showed small differences in seed shape. SmartGrain removed areas of awns and pedicels automatically, and several QTLs were detected for six shape parameters. The allelic effect of a QTL for seed length detected on chromosome 11 was confirmed in advanced backcross progeny; the cv Nipponbare allele increased seed length and, thus, seed weight. High-throughput measurement with SmartGrain reduced sampling error and made it possible to distinguish between lines with small differences in seed shape. SmartGrain could accurately recognize seed not only of rice but also of several other species, including Arabidopsis (Arabidopsis thaliana). The software is free to researchers.

  16. Probing thermodynamic fluctuations in high temperature superconductors

    Science.gov (United States)

    Vidal, Felix; Veira, J. A.; Maza, J.; Miguélez, F.; Morán, E.; Alario, M. A.

    1988-04-01

    We probe thermodynamic fluctuations in HTSC by measuring the excess electrical conductivity, Δσ, abovr T c in single-phase (within 4%) Ba 2LnCu 3O 7-δ compounds, with LnY, Ho and Sm. As expected, the measured relative effect, Δσ / σ (300 K), is much more important in HTSC than for low-temperature superconductors (at least one order of magnitude). In the reduced temperature region -5=-0.47 ± 0.06. This result confirms an universal critical behaviour of Δσ in HTSC, and the value of agrees with that predicted by the Aslamazov-Larkin (AL) theory for three-dimensional BCS superconductivity. However, A shows a normal conductivity dependence which is not accounted for by the AL theory.

  17. Elastic properties and stress-temperature phase diagrams of high-temperature phases with low-temperature lattice instabilities

    Science.gov (United States)

    Thomas, John C.; Van der Ven, Anton

    2014-12-01

    The crystal structures of many technologically important high-temperature phases are predicted to have lattice instabilities at low temperature, making their thermodynamic and mechanical properties inaccessible to standard first principles approaches that rely on the (quasi) harmonic approximation. Here, we use the recently developed anharmonic potential cluster expansion within Monte Carlo simulations to predict the effect of temperature and anisotropic stress on the elastic properties of ZrH2, a material that undergoes diffusionless transitions among cubic, tetragonal, and orthorhombic phases. Our analysis shows that the mechanical properties of high-temperature phases with low-temperature vibrational instabilities are very sensitive to temperature and stress state. These findings have important implications for materials characterization and multi-scale simulations and suggest opportunities for enhanced strain engineering of high-temperature phases exhibiting soft-mode instabilities.

  18. 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...

  19. Confinement Studies in High Temperature Spheromak Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Hill, D N; Mclean, H S; Wood, R D; Casper, T A; Cohen, B I; Hooper, E B; LoDestro, L L; Pearlstein, L D; Romero-Talamas, C

    2006-10-23

    Recent results from the SSPX spheromak experiment demonstrate the potential for obtaining good energy confinement (Te > 350eV and radial electron thermal diffusivity comparable to tokamak L-mode values) in a completely self-organized toroidal plasma. A strong decrease in thermal conductivity with temperature is observed and at the highest temperatures, transport is well below that expected from the Rechester-Rosenbluth model. Addition of a new capacitor bank has produced 60% higher magnetic fields and almost tripled the pulse length to 11ms. For plasmas with T{sub e} > 300eV, it becomes feasible to use modest (1.8MW) neutral beam injection (NBI) heating to significantly change the power balance in the core plasma, making it an effective tool for improving transport analysis. We are now developing detailed designs for adding NBI to SSPX and have developed a new module for the CORSICA transport code to compute the correct fast-ion orbits in SSPX so that we can simulate the effect of adding NBI; initial results predict that such heating can raise the electron temperature and total plasma pressure in the core by a factor of two.

  20. 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).

  1. High Temperature Deformation Mechanisms in a DLD Nickel Superalloy

    Directory of Open Access Journals (Sweden)

    Sean Davies

    2017-04-01

    Full Text Available The realisation of employing Additive Layer Manufacturing (ALM technologies to produce components in the aerospace industry is significantly increasing. This can be attributed to their ability to offer the near-net shape fabrication of fully dense components with a high potential for geometrical optimisation, all of which contribute to subsequent reductions in material wastage and component weight. However, the influence of this manufacturing route on the properties of aerospace alloys must first be fully understood before being actively applied in-service. Specimens from the nickel superalloy C263 have been manufactured using Powder Bed Direct Laser Deposition (PB-DLD, each with unique post-processing conditions. These variables include two build orientations, vertical and horizontal, and two different heat treatments. The effects of build orientation and post-process heat treatments on the materials’ mechanical properties have been assessed with the Small Punch Tensile (SPT test technique, a practical test method given the limited availability of PB-DLD consolidated material. SPT testing was also conducted on a cast C263 variant to compare with PB-DLD derivatives. At both room and elevated temperature conditions, differences in mechanical performances arose between each material variant. This was found to be instigated by microstructural variations exposed through microscopic and Energy Dispersive X-ray Spectroscopy (EDS analysis. SPT results were also compared with available uniaxial tensile data in terms of SPT peak and yield load against uniaxial ultimate tensile and yield strength.

  2. High Temperature Deformation Mechanisms in a DLD Nickel Superalloy.

    Science.gov (United States)

    Davies, Sean; Jeffs, Spencer; Lancaster, Robert; Baxter, Gavin

    2017-04-26

    The realisation of employing Additive Layer Manufacturing (ALM) technologies to produce components in the aerospace industry is significantly increasing. This can be attributed to their ability to offer the near-net shape fabrication of fully dense components with a high potential for geometrical optimisation, all of which contribute to subsequent reductions in material wastage and component weight. However, the influence of this manufacturing route on the properties of aerospace alloys must first be fully understood before being actively applied in-service. Specimens from the nickel superalloy C263 have been manufactured using Powder Bed Direct Laser Deposition (PB-DLD), each with unique post-processing conditions. These variables include two build orientations, vertical and horizontal, and two different heat treatments. The effects of build orientation and post-process heat treatments on the materials' mechanical properties have been assessed with the Small Punch Tensile (SPT) test technique, a practical test method given the limited availability of PB-DLD consolidated material. SPT testing was also conducted on a cast C263 variant to compare with PB-DLD derivatives. At both room and elevated temperature conditions, differences in mechanical performances arose between each material variant. This was found to be instigated by microstructural variations exposed through microscopic and Energy Dispersive X-ray Spectroscopy (EDS) analysis. SPT results were also compared with available uniaxial tensile data in terms of SPT peak and yield load against uniaxial ultimate tensile and yield strength.

  3. First high-temperature electronics products survey 2005.

    Energy Technology Data Exchange (ETDEWEB)

    Normann, Randy Allen

    2006-04-01

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

  4. High-resolution wavefront shaping with a photonic crystal fiber for multimode fiber imaging

    NARCIS (Netherlands)

    Amitonova, L. V.; Descloux, A.; Petschulat, J.; Frosz, M. H.; Ahmed, G.; Babic, F.; Jiang, X.; Mosk, A. P.; Russell, P. S. J.; Pinkse, P.W.H.

    2016-01-01

    We demonstrate that a high-numerical-aperture photonic crystal fiber allows lensless focusing at an unparalleled res- olution by complex wavefront shaping. This paves the way toward high-resolution imaging exceeding the capabilities of imaging with multi-core single-mode optical fibers. We analyze

  5. High-resolution wavefront shaping with a photonic crystal fiber for multimode fiber imaging

    NARCIS (Netherlands)

    Amitonova, Lyubov; Descloux, Adrien; Petschulat, Joerg; Frosz, Michael H.; Ahmed, Goran; Babic, Fehim; Mosk, Allard; Russell, Philip St.J.; Pinkse, Pepijn Willemszoon Harry

    2016-01-01

    We demonstrate that a high-numerical-aperture photonic crystal fiber allows lensless focusing at an unparalleled resolution by complex wavefront shaping. This paves the way toward high-resolution imaging exceeding the capabilities of imaging with multi-core single-mode optical fibers. We analyze the

  6. High solid-state fluorescence in ring-shaped AEE-active tetraphenylsilole derivatives.

    Science.gov (United States)

    Cai, Yuanjing; Samedov, Kerim; Albright, Haley; Dolinar, Brian S; Guzei, Ilia A; Hu, Rongrong; Zhang, Chaocan; Tang, Ben Zhong; West, Robert

    2014-10-28

    Three ring-shaped AEE-active silole-containing compounds were synthesized by mild condensation reactions. Cyclotrisiloxane compound 1 displays high solid-state quantum yield (Φfl = 0.86) with the fluorescence maximum at 512 nm. This high fluorescence efficiency results mainly from decreased vibrational pathways to fluorescence decay due to the intramolecular C-H···π interactions.

  7. Regulation of flow through a T-Shaped open cavity by temperature dependent P, PI, and PID controllers

    Science.gov (United States)

    Saha, Sourav; Mojumder, Satyajit; Saha, Sumon

    2016-07-01

    P (proportional), PI (proportional-integral), and PID (proportional-integral-derivative) controllers are popular means of controlling industrial processes. Due to superior response, accuracy, and stable performance, PID controllers are mostly used in control systems. This paper presents a mathematical model and subsequent response analysis regarding regulation of flow in mixed convection through a T-shaped open cavity by temperature dependent controllers. The T-shaped cavity has cold top and hot bottom walls, while air is flowing through the inlet at surrounding temperature. The inflow is regulated by a controlled gate which operates according to the signal received from the controller. Values of proportional gain (kp), integral gain (ki), and derivative gain (kd) are varied to obtain the desired system response and to ensure a stable system with fastest response. At first, only P controller is used and eventually PI and finally PID control scheme is applied for controller tuning. Tuning of different controllers (P, PI, and PID) are carried out systematically based on the reference temperature which is continuously monitored at a certain location inside the cavity. It is found that PID controller performs better than P or PI controller.

  8. Regulation of flow through a T-Shaped open cavity by temperature dependent P, PI, and PID controllers

    Energy Technology Data Exchange (ETDEWEB)

    Saha, Sourav, E-mail: ssaha09@me.buet.ac.bd; Mojumder, Satyajit, E-mail: satyajit@me.buet.ac.bd; Saha, Sumon, E-mail: sumonsaha@me.buet.ac.bd [Department of Mechanical Engineering, Bangladesh University of Engineering and Technology, Dhaka-1000 (Bangladesh)

    2016-07-12

    P (proportional), PI (proportional-integral), and PID (proportional-integral-derivative) controllers are popular means of controlling industrial processes. Due to superior response, accuracy, and stable performance, PID controllers are mostly used in control systems. This paper presents a mathematical model and subsequent response analysis regarding regulation of flow in mixed convection through a T-shaped open cavity by temperature dependent controllers. The T-shaped cavity has cold top and hot bottom walls, while air is flowing through the inlet at surrounding temperature. The inflow is regulated by a controlled gate which operates according to the signal received from the controller. Values of proportional gain (k{sub p}), integral gain (k{sub i}), and derivative gain (k{sub d}) are varied to obtain the desired system response and to ensure a stable system with fastest response. At first, only P controller is used and eventually PI and finally PID control scheme is applied for controller tuning. Tuning of different controllers (P, PI, and PID) are carried out systematically based on the reference temperature which is continuously monitored at a certain location inside the cavity. It is found that PID controller performs better than P or PI controller.

  9. Laser-Doppler vibrating tube densimeter for measurements at high temperatures and pressures.

    Science.gov (United States)

    Aida, Tsutomu; Yamazaki, Ai; Akutsu, Makoto; Ono, Takumi; Kanno, Akihiro; Hoshina, Taka-aki; Ota, Masaki; Watanabe, Masaru; Sato, Yoshiyuki; Smith, Richard L; Inomata, Hiroshi

    2007-11-01

    A laser-Doppler vibrometer was used to measure the vibration of a vibrating tube densimeter for measuring P-V-T data at high temperatures and pressures. The apparatus developed allowed the control of the residence time of the sample so that decomposition at high temperatures could be minimized. A function generator and piezoelectric crystal was used to excite the U-shaped tube in one of its normal modes of vibration. Densities of methanol-water mixtures are reported for at 673 K and 40 MPa with an uncertainty of 0.009 g/cm3.

  10. A model of evaluating the pseudogap temperature for high ...

    Indian Academy of Sciences (India)

    We have presented a model of evaluating the pseudogap temperature for high temperature superconductors using paraconductivity approach. The theoretical analysis is based on the crossing point technique of the conductivity expressions. The pseudogap temperature T ∗ is found to depend on dimension and is ...

  11. Predicting High Temperature Dislocation Physics in HCP Crystal Structures

    Energy Technology Data Exchange (ETDEWEB)

    Hunter, Abigail [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Carpenter, John S. [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Martinez Saez, Enrique [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-05-09

    This report applies models and experiments to answer key questions about the way materials deform; specifics regarding phase field dislocations dynamics; as well as high temperature rolling experiments.

  12. Gallium Oxide Nanostructures for High Temperature Sensors

    Energy Technology Data Exchange (ETDEWEB)

    Chintalapalle, Ramana V. [Univ. of Texas, El Paso, TX (United States)

    2015-04-30

    Gallium oxide (Ga2O3) thin films were produced by sputter deposition by varying the substrate temperature (Ts) in a wide range (Ts=25-800 °C). The structural characteristics and electronic properties of Ga2O3 films were evaluated using X-ray diffraction (XRD), scanning electron microscopy (SEM), energy-dispersive X-ray spectrometry (EDS), Rutherford backscattering spectrometry (RBS) and spectrophotometric measurements. The effect of growth temperature is significant on the chemistry, crystal structure and morphology of Ga2O3 films. XRD and SEM analyses indicate that the Ga2O3 films grown at lower temperatures were amorphous while those grown at Ts≥500 oC were nanocrystalline. RBS measurements indicate the well-maintained stoichiometry of Ga2O3 films at Ts=300-800 °C. The electronic structure determination indicated that the nanocrystalline Ga2O3films exhibit a band gap of ~5 eV. Tungsten (W) incorporated Ga2O3 films were produced by co-sputter deposition. W-concentration was varied by the applied sputtering-power. No secondary phase formation was observed in W-incorporated Ga2O3 films. W-induced effects were significant on the structure and electronic properties of Ga2O3 films. The band gap of Ga2O3 films without W-incorporation was ~5 eV. Oxygen sensor characteristics evaluated using optical and electrical methods indicate a faster response in W-doped Ga2O3 films compared to intrinsic Ga2O3 films. The results demonstrate the applicability of both intrinsic and W-doped Ga-oxide films for oxygen sensor application at temperatures ≥700 °C.

  13. Temperature of Heating and Cooling of Massive, Thin, and Wedge-Shaped Plates from Hard-to-Machine Steels During Their Grinding

    Science.gov (United States)

    Dement‧ev, V. B.; Ivanova, T. N.; Dolginov, A. M.

    2017-01-01

    Grinding of flat parts occurs by solid abrasive particles due to the physicomechanical process of deformation and to the action of a process liquid at high temperatures in a zone small in volume and difficult for observation. The rate of heating and cooling depends on the change in the intensity of the heat flux and in the velocity and time of action of the heat source. A study has been made of the regularities of the influence of each of these parameters on the depth and character of structural transformations during the grinding of flat parts from hard-to-machine steels. A procedure to calculate temperature in grinding massive, thin, and wedge-shaped parts has been developed with account taken of the geometric and thermophysical parameters of the tool and the treated part, and also of cutting regimes. The procedure can be used as a constituent part in developing a system for automatic design of the technological process of grinding of flat surfaces. A relationship between the temperature in the grinding zone and the regimes of treatment has been established which makes it possible to control the quality of the surface layer of massive, thin, and wedge-shaped plates from hard-to-machine steels. The rational boundaries of shift of cutting regimes have been determined.

  14. Characteristics of Wind Velocity and Temperature Change Near an Escarpment-Shaped Road Embankment

    Directory of Open Access Journals (Sweden)

    Young-Moon Kim

    2014-01-01

    Full Text Available Artificial structures such as embankments built during the construction of highways influence the surrounding airflow. Various types of damage can occur due to changes in the wind velocity and temperature around highway embankments. However, no study has accurately measured micrometeorological changes (wind velocity and temperature due to embankments. This study conducted a wind tunnel test and field measurement to identify changes in wind velocity and temperature before and after the construction of embankments around roads. Changes in wind velocity around an embankment after its construction were found to be influenced by the surrounding wind velocity, wind angle, and the level difference and distance from the embankment. When the level difference from the embankment was large and the distance was up to 3H, the degree of wind velocity declines was found to be large. In changes in reference wind velocities around the embankment, wind velocity increases were not proportional to the rate at which wind velocities declined. The construction of the embankment influenced surrounding temperatures. The degree of temperature change was large in locations with large level differences from the embankment at daybreak and during evening hours when wind velocity changes were small.

  15. High temperature lithium cells with solid polymer electrolytes

    Science.gov (United States)

    Yang, Jin; Eitouni, Hany Basam; Singh, Mohit

    2017-03-07

    Electrochemical cells that use electrolytes made from new polymer compositions based on poly(2,6-dimethyl-1,4-phenylene oxide) and other high-softening-temperature polymers are disclosed. These materials have a microphase domain structure that has an ionically-conductive phase and a phase with good mechanical strength and a high softening temperature. In one arrangement, the structural block has a softening temperature of about 210.degree. C. These materials can be made with either homopolymers or with block copolymers. Such electrochemical cells can operate safely at higher temperatures than have been possible before, especially in lithium cells. The ionic conductivity of the electrolytes increases with increasing temperature.

  16. Temperature and precipitation shape the distribution of harmful cyanobacteria in subtropical lotic and lentic ecosystems.

    Science.gov (United States)

    Haakonsson, Signe; Rodríguez-Gallego, Lorena; Somma, Andrea; Bonilla, Sylvia

    2017-12-31

    Cyanobacterial blooms are expected to become more frequent in freshwaters globally due to eutrophication and climate change effects. However, our knowledge about cyanobacterial biogeography in the subtropics, particularly in lotic ecosystems, is still very limited and the relationship of blooms to temperature and precipitation remains unclear. We took advantage of a comprehensive database of field data compiled over several years (1997 to 2015) to compare cyanobacteria biomass and distribution between lentic and lotic subtropical freshwaters (36 ecosystems, 30°-35°S) and to investigate the role of water temperature and precipitation as significant predictors in eutrophic ecosystems. A filamentous Nostocales, Dolichospermum (Anabaena), was the most widely distributed and frequent genus in the region of the study, followed by the colonial Microcystis, supporting observations of a global latitudinal pattern. Similar total cyanobacteria biovolumes (TCB) were found in lentic and lotic ecosystems, but the proportion of Dolichospermum was higher in lotic ecosystems. Using generalized linear models (GLMs), we found that temperature and rainfall explained 27% of the variation in TCB in lotic ecosystems, while temperature explained 19 and 28% of Dolichospermum and Microcystis biovolume, respectively. In lentic ecosystems, accumulated rainfall explained 34% of the variation of Microcystis biovolume while temperature explained 64%. Our results imply that the increase in extreme meteorological events and temperature predicted by climate models will promote increasingly severe cyanobacterial blooms in eutrophic subtropical freshwaters. Our analysis provides new information about the occurrence of bloom-forming cyanobacteria for southeastern South America and thus fills an important knowledge gap for subtropical freshwaters. Copyright © 2017 Elsevier B.V. All rights reserved.

  17. Design Guideline for New Generation of High-Temperature Guarded Hot Plate

    Science.gov (United States)

    Wu, J.; Hameury, J.; Failleau, G.; Blahut, A.; Vachova, T.; Strnad, R.; Krause, M.; Rafeld, E.; Hammerschmidt, U.

    2018-02-01

    This paper complements the existing measurement standards and literature for high-temperature guarded hot plates (HTGHPs) by addressing specific issues relating to thermal conductivity measurement of technical insulation at high temperatures. The examples given are focused on the designs of HTGHPs for measuring thin thermal insulation. The sensitivity studies have been carried out on major influencing factors that affect the thermal conductivity measurements using HTGHPs, e.g., the uncertainty of temperature measurements, plate flatness and center-guard gap design and imbalance. A new configuration of center-guard gap with triangular shape cross section has been optimized to obtain the same thermal resistance as a 2 mm wide gap with rectangular shape cross section that has been used in the HTGHPs at NPL and LNE. Recommendations have been made on the selections of heater plate materials, high-temperature high-emissivity coatings and miniature temperature sensors. For the first time, thermal stress analysis method has been applied to the field of HTGHPs, in order to estimate the effect of differential thermal expansion on the flatness of thin rigid specimens during thermal conductivity tests in a GHP.

  18. Advanced Plasma Shape Control to Enable High-Performance Divertor Operation on NSTX-U

    Science.gov (United States)

    Vail, Patrick; Kolemen, Egemen; Boyer, Mark; Welander, Anders

    2017-10-01

    This work presents the development of an advanced framework for control of the global plasma shape and its application to a variety of shape control challenges on NSTX-U. Operations in high-performance plasma scenarios will require highly-accurate and robust control of the plasma poloidal shape to accomplish such tasks as obtaining the strong-shaping required for the avoidance of MHD instabilities and mitigating heat flux through regulation of the divertor magnetic geometry. The new control system employs a high-fidelity model of the toroidal current dynamics in NSTX-U poloidal field coils and conducting structures as well as a first-principles driven calculation of the axisymmetric plasma response. The model-based nature of the control system enables real-time optimization of controller parameters in response to time-varying plasma conditions and control objectives. The new control scheme is shown to enable stable and on-demand plasma operations in complicated magnetic geometries such as the snowflake divertor. A recently-developed code that simulates the nonlinear evolution of the plasma equilibrium is used to demonstrate the capabilities of the designed shape controllers. Plans for future real-time implementations on NSTX-U and elsewhere are also presented. Supported by the US DOE under DE-AC02-09CH11466.

  19. Spectroscopic diagnostics of high temperature plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Moos, W.

    1990-01-01

    A three-year research program for the development of novel XUV spectroscopic diagnostics for magnetically confined fusion plasmas is proposed. The new diagnostic system will use layered synthetic microstructures (LSM) coated, flat and curved surfaces as dispersive elements in spectrometers and narrow band XUV filter arrays. In the framework of the proposed program we will develop impurity monitors for poloidal and toroidal resolved measurements on PBX-M and Alcator C-Mod, imaging XUV spectrometers for electron density and temperature fluctuation measurements in the hot plasma core in TEXT or other similar tokamaks and plasma imaging devices in soft x-ray light for impurity behavior studies during RF heating on Phaedrus T and carbon pellet ablation in Alcator C-Mod. Recent results related to use of multilayer in XUV plasma spectroscopy are presented. We also discuss the latest results reviewed to q{sub o} and local poloidal field measurements using Zeeman polarimetry.

  20. High Temperature Processable Flexible Polymer Films

    Science.gov (United States)

    Sundar, D. Shanmuga; Raja, A. Sivanantha; Sanjeeviraja, C.; Jeyakumar, D.

    Recent developments in the field of flexible electronics motivated the researchers to start working in verdict of new flexible substrate for replacing the existing rigid glass and flexible plastics. Flexible substrates offer significant rewards in terms of being able to fabricate flexible electronic devices that are robust, thinner, conformable, lighter and can be rolled away when needed. In this work, a new flexible and transparent substrate with the help of organic materials such as Polydimethylsiloxane (PDMS) and tetra ethoxy orthosilicate (TEOS) is synthesized. Transmittance of about 90-95% is acquired in the visible region (400-700nm) and the synthesized substrate shows better thermal characteristics and withstands temperature up to 200∘C without any significant degradation. Characteristics such as transmittance (T), absorption (A), reflectance (R), refractive index (n) and extinction coefficient (k) are also reported.

  1. High Temperature Superconductivity in Cuprates: a model

    CERN Document Server

    Silva, P R

    2010-01-01

    A model is proposed such that quasi-particles (electrons or holes) residing in the CuO2 planes of cuprates may interact leading to metallic or superconducting behaviors. The metallic phase is obtained when the quasi-particles are treated as having classical kinetic energies and the superconducting phase occurs when the quasi-particles are taken as extremely relativistic objects. The interaction between both kinds of particles is provided by a force dependent-on-velocity. In the case of the superconducting behavior, the motion of apical oxygen ions provides the glue to establish the Cooper pair. The model furnishes explicit relations for the Fermi velocity, the perpendicular and the in-plane coherence lengths, the zero-temperature energy gap, the critical current density, the critical parallel and perpendicular magnetic fields. All these mentioned quantities are expressed in terms of fundamental physical constants as: charge and mass of the electron, light velocity in vacuum, Planck constant, electric permitti...

  2. Study of High Temperature Insulation Materials

    Directory of Open Access Journals (Sweden)

    Vaclav Mentlik

    2004-01-01

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

  3. High temperature performance of polymer composites

    CERN Document Server

    Keller, Thomas

    2014-01-01

    The authors explain the changes in the thermophysical and thermomechanical properties of polymer composites under elevated temperatures and fire conditions. Using microscale physical and chemical concepts they allow researchers to find reliable solutions to their engineering needs on the macroscale. In a unique combination of experimental results and quantitative models, a framework is developed to realistically predict the behavior of a variety of polymer composite materials over a wide range of thermal and mechanical loads. In addition, the authors treat extreme fire scenarios up to more than 1000°C for two hours, presenting heat-protection methods to improve the fire resistance of composite materials and full-scale structural members, and discuss their performance after fire exposure. Thanks to the microscopic approach, the developed models are valid for a variety of polymer composites and structural members, making this work applicable to a wide audience, including materials scientists, polymer chemist...

  4. High-Temperature Coatings Offer Energy Savings

    Science.gov (United States)

    2012-01-01

    The U.S. X-Plane Program included the first-of-its-kind research in aerodynamics and astronautics with experimental vehicles, including the first aircraft to break the sound barrier; the first aircraft to fly in excess of 100,000, then 200,000, and then 300,000 feet; and the first aircraft to fly at three, four, five, and then six times the speed of sound. During the 1990s, NASA started developing a new thermal protection material to test on the X-33 and X-34 supersonic aircraft. The X-33 was intended to demonstrate the technologies needed for a new reusable launch vehicle and was projected to reach an altitude of approximately 50 miles and speeds of more than Mach 11. The X-34, a small, reusable technology demonstrator for a launch vehicle, was intended to reach an altitude of 250,000 feet and fly at speeds of Mach 8. As a result of its research and development efforts, NASA s Ames Research Center invented the Protective Ceramic Coating Material (PCCM). Applied to a surface, the thin, lightweight coating could protect the material underneath from extreme temperatures. The capability of the technology came from its emissivity, which radiated heat away from the surface it covered, thereby decreasing the amount of heat transferred to the underlying material. PCCM not only increased the capability of materials to withstand higher temperatures, it also exhibited impressive thermal shock, vibration, and acoustic performance. In addition, it proved to be resistant to abrasion and mechanical damage and was also environmentally safe, due to it being water-based and containing no solvents. Even though funding for the X-33 and X-34 ended in 2001, PCCM continued on a path of innovation.

  5. Advanced High-Temperature, High-Pressure Transport Reactor Gasification

    Energy Technology Data Exchange (ETDEWEB)

    Michael Swanson; Daniel Laudal

    2008-03-31

    . Higher-reactivity (low-rank) coals appear to perform better in a transport reactor than the less reactive bituminous coals. Factors that affect TRDU product gas quality appear to be coal type, temperature, and air/coal ratios. Testing with a higher-ash, high-moisture, low-rank coal from the Red Hills Mine of the Mississippi Lignite Mining Company has recently been completed. Testing with the lignite coal generated a fuel gas with acceptable heating value and a high carbon conversion, although some drying of the high-moisture lignite was required before coal-feeding problems were resolved. No ash deposition or bed material agglomeration issues were encountered with this fuel. In order to better understand the coal devolatilization and cracking chemistry occurring in the riser of the transport reactor, gas and solid sampling directly from the riser and the filter outlet has been accomplished. This was done using a baseline Powder River Basin subbituminous coal from the Peabody Energy North Antelope Rochelle Mine near Gillette, Wyoming.

  6. Photochemistry at high temperatures - potential of ZnO as a high temperature photocatalyst

    Energy Technology Data Exchange (ETDEWEB)

    Schubnell, M.; Beaud, P.; Kamber, I. [Paul Scherrer Inst. (PSI), Villigen (Switzerland)

    1997-06-01

    Direct conversion of solar radiation into useful, storeable and transportable chemical products is the primary goal of solar chemistry. In this paper we discuss some fundamental aspects of photochemistry at elevated temperatures. We show that luminescence can serve as an indicator of the potential use of a system as a photoconverter. As an example we present experimental data on the chemical potential and on the lifetime of the excited states of ZnO. The low luminescence quantum yield together with a lifetime of about 200 ps indicate that an efficient photochemical conversion on ZnO is highly improbable. We believe this to be a general feature of chemical systems based on a semiconductor photocatalyst, in particular of photoreactions at a solid/gas interface. (author) 3 figs., 6 refs

  7. High Temperature Superconductor Resonator Detectors Project

    Data.gov (United States)

    National Aeronautics and Space Administration — There is a well-established need for more sensitive detectors in the 10 - 200 um wavelength range with high detectivity, D*>1010 cm-Hz1/2/W to increase the...

  8. Dynamic mechanical response and a constitutive model of Fe-based high temperature alloy at high temperatures and strain rates.

    Science.gov (United States)

    Su, Xiang; Wang, Gang; Li, Jianfeng; Rong, Yiming

    2016-01-01

    The effects of strain rate and temperature on the dynamic behavior of Fe-based high temperature alloy was studied. The strain rates were 0.001-12,000 s(-1), at temperatures ranging from room temperature to 800 °C. A phenomenological constitutive model (Power-Law constitutive model) was proposed considering adiabatic temperature rise and accurate material thermal physical properties. During which, the effects of the specific heat capacity on the adiabatic temperature rise was studied. The constitutive model was verified to be accurate by comparison between predicted and experimental results.

  9. SiC device development for high temperature sensor applications

    Science.gov (United States)

    Shor, J. S.; Goldstein, David; Kurtz, A. D.; Osgood, R. M.

    1992-01-01

    Progress made in the processing and characterization of 3C-SiC for high temperature sensor applications is reviewed. Piezoresistance properties of silicon carbide and the temperature coefficient of resistivity of n-type beta-SiC are presented. In addition, photoelectrical etching and dopant selective etch-stops in SiC and high temperature Ohmic contacts for n-type beta-SiC sensors are discussed.

  10. Dynamic high-temperature Kolsky tension bar techniques

    OpenAIRE

    Song Bo; Nelson Kevin; Lipinski Ronald; Bignell John; Ulrich G.B.; George E.P.

    2015-01-01

    Kolsky tension bar techniques were modified for dynamic high-temperature tensile characterization of thin-sheet alloys. An induction coil heater was used to heat the specimen while a cooling system was applied to keep the bars at room temperature during heating. A preload system was developed to generate a small pretension load in the bar system during heating in order to compensate for the effect of thermal expansion generated in the high-temperature tensile specimen. A laser system was appl...

  11. TECHNOLOGY FOR OBTAINING BIMETALLIC SHAPING PARTS OF DIE TOOLING USING METHOD OF HIGH-SPEED HOT EXTRUSION

    Directory of Open Access Journals (Sweden)

    I. V. Kachanov

    2014-01-01

    Full Text Available Processes of high-speed shaping changes and especially high-speed hot extrusion create efficient conditions for treatment of weakly plastic and poorly deformable materials which are widely used in tool making facilities. Due to the fact that high-speed stamping provides accurate billets with increased mechanical properties, it can be used as a technological process for manufacturing shaping parts of die tooling parts operating which are subjected to increased loads and wear.The purpose of the paper is to carry out experimental investigations on the possibility to obtain a bimetallic tool where structural steel is considered as a basis of the tool and a working cavity is made of high-alloyed tool steel with its saving up to 90 %. A scheme of loading and geometry of conjugated surfaces of the composite billet have been developed in the paper. Technology for obtaining bimetallic shaping parts of die tooling with deformation at speed of vR = 40-50 m/s and composite billet temperature of T = 1150 °C has been experimentally tested with formation of a compound due to plastic flow of two billet parts on contact surface with removal of surface oxide films.Microstructures of the bimetallic compounds obtained with the help of high-speed hot extrusion method for compositions of structural and high-alloy steels have been investigated and their high quality has been proved during the investigations. Dependences of micro-hardness distribution have been established outbound two- steel contact plane in the zone of connection that are characterized by a minimum micro-hardness value in the connection joint. Availability of more plastic zone in the contact plane contributes to reduction of residual stresses due to their relaxation in this zone and higher joint strength.

  12. Extruded Self-Lubricating Solid For High-Temperature Use

    Science.gov (United States)

    Sliney, H. E.; Waters, W. J.; Soltis, R. F.; Bemis, K.

    1996-01-01

    "EX-212" denotes high-density extruded form of composite solid material self-lubricating over wide range of temperatures. Properties equal or exceed those of powder-metallurgy version of this material. Developed for use in advanced engines at high temperatures at which ordinary lubricants destroyed.

  13. High temperature heat exchange: nuclear process heat applications

    Energy Technology Data Exchange (ETDEWEB)

    Vrable, D.L.

    1980-09-01

    The unique element of the HTGR system is the high-temperature operation and the need for heat exchanger equipment to transfer nuclear heat from the reactor to the process application. This paper discusses the potential applications of the HTGR in both synthetic fuel production and nuclear steel making and presents the design considerations for the high-temperature heat exchanger equipment.

  14. Electron beam damage in high temperature polymers

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-01-01

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

  15. InGaN High Temperature Photovoltaic Cells Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The objectives of this Phase II project are to develop InGaN photovoltaic cells for high temperature and/or high radiation environments to TRL 4 and to define the...

  16. Giant and reversible room-temperature elastocaloric effect in a single-crystalline Ni-Fe-Ga magnetic shape memory alloy

    National Research Council Canada - National Science Library

    Li, Yang; Zhao, Dewei; Liu, Jian

    2016-01-01

    Good mechanical properties and large adiabatic temperature change render Heusler-type Ni2FeGa-based magnetic shape memory alloys as a promising candidate material for solid-state mechanical cooling...

  17. Choroidal findings in dome-shaped macula in highly myopic eyes: a longitudinal study.

    Science.gov (United States)

    Viola, Francesco; Dell'Arti, Laura; Benatti, Eleonora; Invernizzi, Alessandro; Mapelli, Chiara; Ferrari, Fabio; Ratiglia, Roberto; Staurenghi, Giovanni; Barteselli, Giulio

    2015-01-01

    To describe choroidal findings in dome-shaped macula associated with high myopia using fluorescein angiography (FA), indocyanine green angiography (ICGA), and spectral-domain optical coherence tomography (SD OCT), and to elucidate the mechanism and natural course of serous retinal detachment (RD) associated with dome-shaped macula. Retrospective, observational case series. We reviewed longitudinal imaging results of 52 highly myopic eyes with dome-shaped macula. Changes on FA and ICGA were assessed. Retinal, choroidal, and scleral thicknesses and bulge height were measured on SD OCT. Serous RD was the most common abnormality associated with dome-shaped macula, detected by SD OCT in 44% of the cases with no associated choroidal neovascularization. Significant differences in the proportion of eyes with pinpoint leakage on FA (P macula was likely caused by choroidal vascular changes, similar to central serous chorioretinopathy, but specifically confined in the inward bulge of the staphyloma and secondary to excessive scleral thickening. Serous retinal detachment showed fluctuating changes over time, with alternating active and inactive stages. Angiographic findings in dome-shaped macula suggest the choroid as a target for possible treatment strategies. Copyright © 2015 Elsevier Inc. All rights reserved.

  18. Tunable polymer multi-shape memory effect.

    Science.gov (United States)

    Xie, Tao

    2010-03-11

    Shape memory polymers are materials that can memorize temporary shapes and revert to their permanent shape upon exposure to an external stimulus such as heat, light, moisture or magnetic field. Such properties have enabled a variety of applications including deployable space structures, biomedical devices, adaptive optical devices, smart dry adhesives and fasteners. The ultimate potential for a shape memory polymer, however, is limited by the number of temporary shapes it can memorize in each shape memory cycle and the ability to tune the shape memory transition temperature(s) for the targeted applications. Currently known shape memory polymers are capable of memorizing one or two temporary shapes, corresponding to dual- and triple-shape memory effects (also counting the permanent shape), respectively. At the molecular level, the maximum number of temporary shapes a shape memory polymer can memorize correlates directly to the number of discrete reversible phase transitions (shape memory transitions) in the polymer. Intuitively, one might deduce that multi-shape memory effects are achievable simply by introducing additional reversible phase transitions. The task of synthesizing a polymer with more than two distinctive and strongly bonded reversible phases, however, is extremely challenging. Tuning shape memory effects, on the other hand, is often achieved through tailoring the shape memory transition temperatures, which requires alteration in the material composition. Here I show that the perfluorosulphonic acid ionomer (PFSA), which has only one broad reversible phase transition, exhibits dual-, triple-, and at least quadruple-shape memory effects, all highly tunable without any change to the material composition.

  19. Grain boundaries in high temperature superconductors

    NARCIS (Netherlands)

    Hilgenkamp, Johannes W.M.; Mannhart, J.

    2002-01-01

    Since the first days of high-Tc superconductivity, the materials science and the physics of grain boundaries in superconducting compounds have developed into fascinating fields of research. Unique electronic properties, different from those of the grain boundaries in conventional metallic

  20. Low-temperature relaxation in NiTi-based shape memory alloys

    Energy Technology Data Exchange (ETDEWEB)

    Torrens-Serra, Joan; Salas, Daniel; Cesari, Eduard; Kustov, Sergey [Departament de Fisica, Universitat de les Illes Balears, cra. de Valldemossa km 7.5, E-07122, Palma de Mallorca (Spain)

    2011-07-01

    We have studied the structural changes occurring in different Ni-Ti and Ni-Ti-Fe alloys over the temperature range from 13 to 300 K by means of mechanical spectroscopy, calorimetry (DSC) and electrical resistivity measurements. Several binary and ternary alloys were used with different thermal and mechanical history, which demonstrate distinct transformation paths: B2-B19', B2-R and B2-R-B19'. Temperature dependence of the internal friction (IF) was studied over the range 90-137 kHz for different strain amplitudes from 3{sup *}10E-7 to 5{sup *}10E-5. In addition to the martensitic and intermartensitic transformations, the IF curves showed a peak at about 90 K in annealed and water-quenched samples independently of their composition which can not be detected by DSC or electrical resistivity measurements. The thermally activated nature of the relaxation has been confirmed using different measurement frequencies. Since the IF peak is observed for ultrasonic frequencies at temperatures of around 90 K, it corresponds to a new relaxation phenomenon, not reported so far in Ni-Ti family of alloys, with the activation energy of the order of only 0.01 eV. On the other hand, no relaxation is found in deformed alloys not subjected to annealing heat treatments. The origin of this relaxation may be attributed to the presence of interstitial hydrogen atoms.

  1. Phase transition analysis of V-shaped liquid crystal: Combined temperature-dependent FTIR and density functional theory approach.

    Science.gov (United States)

    Singh, Swapnil; Singh, Harshita; Karthick, T; Tandon, Poonam; Prasad, Veena

    2018-01-05

    Temperature-dependent Fourier transform infrared spectroscopy (FTIR) combined with density functional theory (DFT) is employed to study the mechanism of phase transitions of V-shaped bent-core liquid crystal. Since it has a large number of flexible bonds, one-dimensional potential energy scan (PES) was performed on the flexible bonds and predicted the most stable conformer I. A detailed analysis of vibrational normal modes of conformer I have been done on the basis of potential energy distribution. The good agreement between the calculated spectrum of conformer I and observed FTIR spectrum at room temperature validates our theoretical structure model. Furthermore, the prominent changes observed in the stretching vibrational bands of CH3/CH2, CO, ring CC, ring CO, ring CH in-plane bending, and ring CH out-of-plane bending at Iso→nematic phase transition (at 155°C) have been illustrated. However, the minor changes in the spectral features observed for the other phase transitions might be due to the shape or bulkiness of molecules. Combined FTIR and PES study beautifully explained the dynamics of the molecules, molecular realignment, H-bonding, and conformational changes at the phase transitions. Copyright © 2017 Elsevier B.V. All rights reserved.

  2. Phase transition analysis of V-shaped liquid crystal: Combined temperature-dependent FTIR and density functional theory approach

    Science.gov (United States)

    Singh, Swapnil; Singh, Harshita; Karthick, T.; Tandon, Poonam; Prasad, Veena

    2018-01-01

    Temperature-dependent Fourier transform infrared spectroscopy (FTIR) combined with density functional theory (DFT) is employed to study the mechanism of phase transitions of V-shaped bent-core liquid crystal. Since it has a large number of flexible bonds, one-dimensional potential energy scan (PES) was performed on the flexible bonds and predicted the most stable conformer I. A detailed analysis of vibrational normal modes of conformer I have been done on the basis of potential energy distribution. The good agreement between the calculated spectrum of conformer I and observed FTIR spectrum at room temperature validates our theoretical structure model. Furthermore, the prominent changes observed in the stretching vibrational bands of CH3/CH2, Cdbnd O, ring CC, ring CO, ring CH in-plane bending, and ring CH out-of-plane bending at Iso → nematic phase transition (at 155 °C) have been illustrated. However, the minor changes in the spectral features observed for the other phase transitions might be due to the shape or bulkiness of molecules. Combined FTIR and PES study beautifully explained the dynamics of the molecules, molecular realignment, H-bonding, and conformational changes at the phase transitions.

  3. Dynamic High-Temperature Characterization of an Iridium Alloy in Compression at High Strain Rates

    Energy Technology Data Exchange (ETDEWEB)

    Song, Bo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Experimental Environment Simulation Dept.; Nelson, Kevin [Sandia National Lab. (SNL-CA), Livermore, CA (United States). Mechanics of Materials Dept.; Lipinski, Ronald J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Advanced Nuclear Fuel Cycle Technology Dept.; Bignell, John L. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States). Structural and Thermal Analysis Dept.; Ulrich, G. B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Radioisotope Power Systems Program; George, E. P. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States). Radioisotope Power Systems Program

    2014-06-01

    Iridium alloys have superior strength and ductility at elevated temperatures, making them useful as structural materials for certain high-temperature applications. However, experimental data on their high-temperature high-strain-rate performance are needed for understanding high-speed impacts in severe elevated-temperature environments. Kolsky bars (also called split Hopkinson bars) have been extensively employed for high-strain-rate characterization of materials at room temperature, but it has been challenging to adapt them for the measurement of dynamic properties at high temperatures. Current high-temperature Kolsky compression bar techniques are not capable of obtaining satisfactory high-temperature high-strain-rate stress-strain response of thin iridium specimens investigated in this study. We analyzed the difficulties encountered in high-temperature Kolsky compression bar testing of thin iridium alloy specimens. Appropriate modifications were made to the current high-temperature Kolsky compression bar technique to obtain reliable compressive stress-strain response of an iridium alloy at high strain rates (300 – 10000 s-1) and temperatures (750°C and 1030°C). Uncertainties in such high-temperature high-strain-rate experiments on thin iridium specimens were also analyzed. The compressive stress-strain response of the iridium alloy showed significant sensitivity to strain rate and temperature.

  4. Low but contrasting neutral genetic differentiation shaped by winter temperature in European great tits.

    NARCIS (Netherlands)

    Lemoine, M.; Lucek, K.; Perrier, C.; Saladin, V.; Adriaensen, F.; Barba, E.; Belda, E.J.; Charmantier, A.; Cichoń, M.; Eeva, T.; Grégoire, A.; Hinde, C.A.; Johnsen, A.; Komdeur, J.; Mänd, R.; Matthysen, E.; Norte, A.C.; Pitala, N.; Sheldon, B.C.; Slagsvold, T.; Tinbergen, J.M.; Török, J.; Ubels, R.; van Oers, K.; Visser, M.E.; Doligez, Blandine; Richner, Heinz

    2016-01-01

    Gene flow is usually thought to reduce genetic divergence and impede local adaptation by homogenising gene pools between populations. However, evidence for local adaptation and phenotypic differentiation in highly mobile species, experiencing high levels of gene flow, is emerging. Assessing

  5. Low but contrasting neutral genetic differentiation shaped by winter temperature in European great tits

    NARCIS (Netherlands)

    Lemoine, Melissa; Lucek, Kay; Perrier, Charles; Saladin, Verena; Adriaensen, Frank; Barba, Emilio; Belda, Eduardo J.; Charmantier, Anne; Cichon, Mariusz; Eeva, Tapio; Gregoire, Arnaud; Hinde, Camilla A.; Johnsen, Arild; Komdeur, Jan; Mand, Raivo; Matthysen, Erik; Norte, Ana Claudia; Pitala, Natalia; Sheldon, Ben C.; Slagsvold, Tore; Tinbergen, Joost M.; Torok, Janos; Ubels, Richard; Van Oers, Kees; Visser, Marcel E.; Doligez, Blandine; Richner, Heinz

    Gene flow is usually thought to reduce genetic divergence and impede local adaptation by homogenising gene pools between populations. However, evidence for local adaptation and phenotypic differentiation in highly mobile species, experiencing high levels of gene flow, is emerging. Assessing

  6. Shape evolution in 76, 78Kr nuclei at high spins in tilted axis ...

    Indian Academy of Sciences (India)

    A two-dimensional tilted axis cranking Hartree–Fock–Bogoliubov (CHFB) calculation is performed for 76Kr and 78Kr nuclei up to high spins = 30 employing a pairing-plus-quadrupole (PPQ) model interaction Hamiltonian. Intricate details of the evolution of single particle structures and shapes as a function of spin have ...

  7. Shape evolution in 76,78Kr nuclei at high spins in tilted axis ...

    Indian Academy of Sciences (India)

    CHFB) calculation is performed for 76Kr and 78Kr nuclei up to high spins J = 30 employing a pairing-plus-quadrupole (PPQ) model interaction Hamiltonian. Intricate details of the evolution of single particle structures and shapes as a function of spin ...

  8. A high-rate shape memory alloy actuator for aerodynamic load control on wind turbines

    NARCIS (Netherlands)

    Lara-Quintanilla, A.; Hulskamp, A.W.; Bersee, H.E.N.

    2013-01-01

    This paper discusses the development of a high rate shape memory alloy (SMA) driven actuator. The concept of the actuator was developed to act as aerodynamic load control surface on wind turbines. It was designed as a plate or beam-like structure with prestrained SMA wires embedded off its neutral

  9. Probing High Temperature Superconductors with Magnetometry in Ultrahigh Magnetic Fields

    Energy Technology Data Exchange (ETDEWEB)

    Li, Lu [Univ. of Michigan, Ann Arbor, MI (United States)

    2017-07-26

    The objective of this research is to investigate the high-field magnetic properties of high temperature superconductors, materials that conduct electricity without loss. A technique known as high-resolution torque magnetometry that was developed to directly measure the magnetization of high temperature superconductors. This technique was implemented using the 65 Tesla pulsed magnetic field facility that is part of the National High Magnetic Field Laboratory at Los Alamos National Laboratory. This research addressed unanswered questions about the interplay between magnetism and superconductivity, determine the electronic structure of high temperature superconductors, and shed light on the mechanism of high temperature superconductivity and on potential applications of these materials in areas such as energy generation and power transmission. Further applications of the technology resolve the novel physical phenomena such as correlated topological insulators, and spin liquid state in quantum magnets.

  10. Analysis of the high-temperature particulate collection problem

    Energy Technology Data Exchange (ETDEWEB)

    Razgaitis, R.

    1977-10-01

    Particulate agglomeration and separation at high temperatures and pressures are examined, with particular emphasis on the unique features of the direct-cycle application of fluidized-bed combustion. The basic long-range mechanisms of aerosol separation are examined, and the effects of high temperature and high pressure on usable collection techniques are assessed. Primary emphasis is placed on those avenues that are not currently attracting widespread research. The high-temperature, particulate-collection problem is surveyed, together with the peculiar requirements associated with operation of turbines with particulate-bearing gas streams. 238 references.

  11. High Temperature Protonic Conductors by Melt Growth

    Science.gov (United States)

    2006-11-21

    electrolyzers, solid state fuel cells, gas separation membranes, moisture sensors and high-density energy storage applications, among others (1-5...A.R. de Arellano-López, A. Sayir. “Microestructura y Comportamiento Plástico de Perovsquitas Conductoras Protónicas de Alta Temperatura ”. Bol. Soc...Conductores Protónicos de Alta Temperatura Crecidos por Fusión de Zona Flotante”. VII Reunión Nacional y VI Conferencia Iberoamericana (Electrocerámica

  12. Microwave synthesis and actuation of shape memory polycaprolactone foams with high speed

    Science.gov (United States)

    Zhang, Fenghua; Zhou, Tianyang; Liu, Yanju; Leng, Jinsong

    2015-06-01

    Microwave technology is a highly effective approach to fast and uniform heating. This article investigates that the microwave heating as a novel method is used to rapidly foam and actuate biocompatible and biodegradable shape memory crosslinked-polycaprolactone (c-PCL) foams. The optical microscope proves that the resulting c-PCL foams have homogenous pore structure. Mechanical behavior and shape memory performance of c-PCL foams are investigated by static materials testing. Shape recovery ratio is approximately 100% and the whole recovery process takes only 98 s when trigged by microwave. Due to the unique principle of microwave heating, the recovery speed of c-PCL foams in microwave oven is several times faster than that in hot water and electric oven. Hence compared to the traditional heating methods, microwave is expected to bring more advantages to modern industry and scientific research in the field of smart materials and structures.

  13. Star-Shaped Polyacrylates: Highly Functionalized Architectures via CuAAC Click Conjugation.

    Science.gov (United States)

    Lammens, Mieke; Fournier, David; Fijten, Martin W M; Hoogenboom, Richard; Prez, Filip Du

    2009-12-01

    Well-defined functional star-shaped polymer structures with up to 29 arms have been successfully synthesized by the combination of atom transfer radical polymerization (ATRP) and click chemistry. First, azide end-functionalized poly(isobornyl acrylate) (PiBA) star-shaped polymers were prepared by successive ATRP and bromine substitution. Subsequently, alkyne end-functionalized molecules and polymers were introduced onto the star-shaped PiBA bearing pendant azide moieties by copper-catalyzed azide-alkyne cycloaddition (CuAAC). The possibilities and limits for the CuAAC on such highly branched polyacrylates are described. Copyright © 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Temperature and Voltage Offsets in High-ZT Thermoelectrics

    Science.gov (United States)

    Levy, George S.

    2017-10-01

    Thermodynamic temperature can take on different meanings. Kinetic temperature is an expectation value and a function of the kinetic energy distribution. Statistical temperature is a parameter of the distribution. Kinetic temperature and statistical temperature, identical in Maxwell-Boltzmann statistics, can differ in other statistics such as those of Fermi-Dirac or Bose-Einstein when a field is present. Thermal equilibrium corresponds to zero statistical temperature gradient, not zero kinetic temperature gradient. Since heat carriers in thermoelectrics are fermions, the difference between these two temperatures may explain voltage and temperature offsets observed during meticulous Seebeck measurements in which the temperature-voltage curve does not go through the origin. In conventional semiconductors, temperature offsets produced by fermionic electrical carriers are not observable because they are shorted by heat phonons in the lattice. In high-ZT materials, however, these offsets have been detected but attributed to faulty laboratory procedures. Additional supporting evidence for spontaneous voltages and temperature gradients includes data collected in epistatic experiments and in the plasma Q-machine. Device fabrication guidelines for testing the hypothesis are suggested including using unipolar junctions stacked in a superlattice, alternating n/n + and p/p + junctions, selecting appropriate dimensions, doping, and loading.

  15. High Temperature Corrosion on Biodust Firing

    DEFF Research Database (Denmark)

    Okoro, Sunday Chukwudi

    The high content of alkali metals and chlorine in biomass gives rise to fouling/slagging and corrosion of heat exchange components, such as superheaters, in biomass fired power plants. Increasing the lifetime of these components, and in addition, preventing unwarranted plant shutdowns due...... to their failure, requires understanding of the complex corrosion mechanisms, as well as development of materials that are resistant to corrosion under biomass firing conditions, thereby motivating the current work. To understand the mechanisms of corrosion attack, comprehensive analysis of corrosion products...... was necessary. In the present work, two complementary methodologies based on analysis of cross sections and plan views were applied to achieve comprehensive characterization of corrosion products. The suitability of these methods for both laboratory scale and full scale corrosion investigations was demonstrated...

  16. High Temperature Superconductor Josephson Weak Links

    Science.gov (United States)

    Hunt, B. D.; Barner, J. B.; Foote, M. C.; Vasquez, R. C.

    1993-01-01

    High T_c edge-geometry SNS microbridges have been fabricated using ion-damaged YBa_2Cu_3O_(7-x) (YBCO) and a nonsuperconducting phase of YBCO (N-YBCO) as normal metals. Optimization of the ion milling process used for YBCO edge formation and cleaning has resulted in ion-damage barrier devices which exhibit I-V characteristics consistent with the Resistively-Shunted-Junction (RSJ) model, with typical current densities (J_c) of approximately 5 x 10^6 A/cm^2 at 4.2 K. Characterization of N-YBCO films suggests that N-YBCO is the orthorhombic YBCO phase with oxygen disorder suppressing T_c...

  17. High skin temperature and hypohydration impair aerobic performance.

    Science.gov (United States)

    Sawka, Michael N; Cheuvront, Samuel N; Kenefick, Robert W

    2012-03-01

    This paper reviews the roles of hot skin (>35°C) and body water deficits (>2% body mass; hypohydration) in impairing submaximal aerobic performance. Hot skin is associated with high skin blood flow requirements and hypohydration is associated with reduced cardiac filling, both of which act to reduce aerobic reserve. In euhydrated subjects, hot skin alone (with a modest core temperature elevation) impairs submaximal aerobic performance. Conversely, aerobic performance is sustained with core temperatures >40°C if skin temperatures are cool-warm when euhydrated. No study has demonstrated that high core temperature (∼40°C) alone, without coexisting hot skin, will impair aerobic performance. In hypohydrated subjects, aerobic performance begins to be impaired when skin temperatures exceed 27°C, and even warmer skin exacerbates the aerobic performance impairment (-1.5% for each 1°C skin temperature). We conclude that hot skin (high skin blood flow requirements from narrow skin temperature to core temperature gradients), not high core temperature, is the 'primary' factor impairing aerobic exercise performance when euhydrated and that hypohydration exacerbates this effect.

  18. Quantitative Temperature Dependence of Longitudinal Spin Seebeck Effect at High Temperatures

    Directory of Open Access Journals (Sweden)

    Ken-ichi Uchida

    2014-11-01

    Full Text Available We report temperature-dependent measurements of longitudinal spin Seebeck effects (LSSEs in Pt/Y_{3}Fe_{5}O_{12} (YIG/Pt systems in a high temperature range from room temperature to above the Curie temperature of YIG. The experimental results show that the magnitude of the LSSE voltage in the Pt/YIG/Pt systems rapidly decreases with increasing the temperature and disappears above the Curie temperature. The critical exponent of the LSSE voltage in the Pt/YIG/Pt systems at the Curie temperature is estimated to be 3, which is much greater than that for the magnetization curve of YIG. This difference highlights the fact that the mechanism of the LSSE cannot be explained in terms of simple static magnetic properties in YIG.

  19. PaCeQuant: A Tool for High-Throughput Quantification of Pavement Cell Shape Characteristics.

    Science.gov (United States)

    Möller, Birgit; Poeschl, Yvonne; Plötner, Romina; Bürstenbinder, Katharina

    2017-11-01

    Pavement cells (PCs) are the most frequently occurring cell type in the leaf epidermis and play important roles in leaf growth and function. In many plant species, PCs form highly complex jigsaw-puzzle-shaped cells with interlocking lobes. Understanding of their development is of high interest for plant science research because of their importance for leaf growth and hence for plant fitness and crop yield. Studies of PC development, however, are limited, because robust methods are lacking that enable automatic segmentation and quantification of PC shape parameters suitable to reflect their cellular complexity. Here, we present our new ImageJ-based tool, PaCeQuant, which provides a fully automatic image analysis workflow for PC shape quantification. PaCeQuant automatically detects cell boundaries of PCs from confocal input images and enables manual correction of automatic segmentation results or direct import of manually segmented cells. PaCeQuant simultaneously extracts 27 shape features that include global, contour-based, skeleton-based, and PC-specific object descriptors. In addition, we included a method for classification and analysis of lobes at two-cell junctions and three-cell junctions, respectively. We provide an R script for graphical visualization and statistical analysis. We validated PaCeQuant by extensive comparative analysis to manual segmentation and existing quantification tools and demonstrated its usability to analyze PC shape characteristics during development and between different genotypes. PaCeQuant thus provides a platform for robust, efficient, and reproducible quantitative analysis of PC shape characteristics that can easily be applied to study PC development in large data sets. © 2017 American Society of Plant Biologists. All Rights Reserved.

  20. High Precision Infrared Temperature Measurement System Based on Distance Compensation

    Directory of Open Access Journals (Sweden)

    Chen Jing

    2017-01-01

    Full Text Available To meet the need of real-time remote monitoring of human body surface temperature for optical rehabilitation therapy, a non-contact high-precision real-time temperature measurement method based on distance compensation was proposed, and the system design was carried out. The microcontroller controls the infrared temperature measurement module and the laser range module to collect temperature and distance data. The compensation formula of temperature with distance wass fitted according to the least square method. Testing had been performed on different individuals to verify the accuracy of the system. The results indicate that the designed non-contact infrared temperature measurement system has a residual error of less than 0.2°C and the response time isless than 0.1s in the range of 0 to 60cm. This provides a reference for developing long-distance temperature measurement equipment in optical rehabilitation therapy.