Extreme enhancement of blocking temperature by strong magnetic dipoles interaction of α-Fe nanoparticle-based high-density agglomerate

International Nuclear Information System (INIS)

Kura, H; Takahashi, M; Ogawa, T

2011-01-01

High-volume fraction α-Fe nanoparticle (NP) agglomerates were prepared using chemically synthesized NPs. In the agglomerate, NPs are separated by surfactant and NP superlattice with a hexagonal close-packed structure is locally realized. Volume fractions of NPs at 20% and 42% were obtained in agglomerates consisting of 2.9 nm and 8.2 nm diameter NPs, respectively. The high saturation magnetization of α-Fe NPs and high volume fraction of NPs in the agglomerate provide strong magnetic dipole-dipole interaction. The interaction energy of the agglomerate became much larger than the anisotropic energy of individual NPs. As a result, the blocking temperature of the 8.2 nm NP agglomerate was significantly enhanced from 52.2 K to around 500 K. (fast track communication)

Creep-fatigue interaction at high temperature; Proceedings of the Symposium, 112th ASME Winter Annual Meeting, Atlanta, GA, Dec. 1-6, 1991

Science.gov (United States)

Haritos, George K.; Ochoa, O. O.

Various papers on creep-fatigue interaction at high temperature are presented. Individual topics addressed include: analysis of elevated temperature fatigue crack growth mechanisms in Alloy 718, physically based microcrack propagation laws for creep-fatigue-environment interaction, in situ SEM observation of short fatigue crack growth in Waspaloy at 700 C under cyclic and dwell conditions, evolution of creep-fatigue life prediction models, TMF design considerations in turbine airfoils of advanced turbine engines. Also discussed are: high temperature fatigue life prediction computer code based on the total strain version of strainrange partitioning, atomic theory of thermodynamics of internal variables, geometrically nonlinear analysis of interlaminar stresses in unsymmetrically laminated plates subjected to uniform thermal loading, experimental investigation of creep crack tip deformation using moire interferometry. (For individual items see A93-31336 to A93-31344)

Predictive Finite Rate Model for Oxygen-Carbon Interactions at High Temperature

Science.gov (United States)

Poovathingal, Savio

An oxidation model for carbon surfaces is developed to predict ablation rates for carbon heat shields used in hypersonic vehicles. Unlike existing empirical models, the approach used here was to probe gas-surface interactions individually and then based on an understanding of the relevant fundamental processes, build a predictive model that would be accurate over a wide range of pressures and temperatures, and even microstructures. Initially, molecular dynamics was used to understand the oxidation processes on the surface. The molecular dynamics simulations were compared to molecular beam experiments and good qualitative agreement was observed. The simulations reproduced cylindrical pitting observed in the experiments where oxidation was rapid and primarily occurred around a defect. However, the studies were limited to small systems at low temperatures and could simulate time scales only of the order of nanoseconds. Molecular beam experiments at high surface temperature indicated that a majority of surface reaction products were produced through thermal mechanisms. Since the reactions were thermal, they occurred over long time scales which were computationally prohibitive for molecular dynamics to simulate. The experiments provided detailed dynamical data on the scattering of O, O2, CO, and CO2 and it was found that the data from molecular beam experiments could be used directly to build a model. The data was initially used to deduce surface reaction probabilities at 800 K. The reaction probabilities were then incorporated into the direct simulation Monte Carlo (DSMC) method. Simulations were performed where the microstructure was resolved and dissociated oxygen convected and diffused towards it. For a gas-surface temperature of 800 K, it was found that despite CO being the dominant surface reaction product, a gas-phase reaction forms significant CO2 within the microstructure region. It was also found that surface area did not play any role in concentration of

Quantum electrodynamics at high temperature. 2

International Nuclear Information System (INIS)

Alvarez-Estrada, R.F.

1988-01-01

The photon sector of QED in d = 3 spatial dimensions is analyzed at high temperature thereby generalizing nontrivially a previous study for d = 1. The imaginary time formalism and an improved renormalized perturbation theory which incorporates second order Debye screening are used. General results are presented for the leading high temperature contributions to all renormalized connected photon Green's functions for fixed external momenta (much smaller than the temperature) to all orders in the improved perturbation theory. Those leading contributions are ultraviolet finite, infrared convergent and gauge invariant, and display an interesting form of dimensional reduction at high temperature. A new path integral representations is given for the high temperature partition function with an external photon source, which is shown to generate all leading high temperature Green's functions mentioned above, and, so, it displays neatly the kind of dimensional reduction which makes QED to become simpler at high temperature. This limiting partition function corresponds to an imaginary time dependent electron positron field interacting with an electromagnetic field at zero imaginary time, and it depends on the renormalized electron mass and electric charge, the second order contribution to the usual renormalization constant Z 3 and a new mass term, which is associated to the photon field with vanishing Lorentz index. The new mass term corresponds to a finite number of diagrams in the high temperature improved perturbation theory and carriers ultraviolet divergences which are compensated for by other contributions (so that the leading high temperature Green's functions referred to above are ultraviolet finite). The dominant high temperature contributions to the renormalized thermodynamic potential to all perturbative orders: i) are given in terms of the above leading high-temperature contributions to the photon Green's functions (except for a few diagrams of low order in the

Experimental Investigations of Boron, Lithium, and Halogens During High-Temperature Water-Rock Interaction: Insights into the Yellowstone Hydrothermal System

Science.gov (United States)

Cullen, J. T.; Hurwitz, S.; Thordsen, J. J.; Barnes, J.

2017-12-01

B, Li, and halogens (Cl, F, Br) are used extensively in studies of thermal waters to infer fluid equilibrium conditions with the host reservoir lithology, and quantify the possible fraction of a magmatic component in thermal waters. Apart from fluorine, the limited number of minerals that incorporate these elements support the notion that they preferentially partition into an aqueous fluid during high temperature water-rock interaction. Although limited experimental work is largely consistent with these observations, a rigorous experimental investigation is required to quantify the mobility of these elements under conditions emulating a silicic hydrothermal system. Here we present the results from water-rhyolite interaction batch experiments conducted over a range of temperatures between 150 °C and 350 °C and 250 bar. Powdered obsidian from Yellowstone was reacted with MiliQ water and sampled intermittently throughout the duration of the 90 day experiment. The experimental data show that at temperatures ≤ 200 °C, B, Cl, Br, and Li are not readily leached from the rhyolite, whereas aqueous F- concentration increases by a factor of 3.5 when the temperature was increased from 150 °C to 200 °C. Between 200 °C and 250 °C, B concentration increased by more than an order of magnitude and Cl- concentration increased by a factor of 5. F- concentration increased by a factor of 3. Between 250 °C and 300 °C the opposite trend was observed, in which F- concentration decreased by 60%, Br- concentration increased by a factor of 5, and Cl- and B concentrations increased by more than an order of magnitude. The progressive decrease of aqueous F- at T ≥ 300 °C is likely controlled by precipitation into a fluorine bearing secondary mineral(s). Our experimental results demonstrate that leaching of B, Li, Cl, F, and Br from rhyolite is highly temperature-dependent between 150 °C and 350 °C. These results can provide context to infer the sources of solutes discharged at

Numerical solutions to the critical state in a magnet-high temperature superconductor interaction

Energy Technology Data Exchange (ETDEWEB)

Ruiz-Alonso, D; Coombs, T A; Campbell, A M [Cambridge University Engineering Department, Trumpington Street, Cambridge CB2 1PZ (United Kingdom)

2005-02-01

This paper presents an algorithm to simulate the electromagnetic behaviour of devices containing high temperature superconductors in axially symmetric problems. The numerical method is built within the finite element method. The electromagnetic properties of HTSCs are described through the critical-state model. Measurements of the axial force between a permanent magnet and a melt-textured YBCO puck are obtained in order to validate the method. This simple system is modelled so that the proposed method obtains the current distribution and electromagnetic fields in the HTSC. The forces in the interaction between the magnet and the HTSC puck can then be calculated. A comparison between experimental and simulation results shows good matching. The simplification of using the critical-state model and ignoring flux creep in this type of configuration is also explored.

Hole-exciton interaction induced high field decay of magneto-electroluminescence in Alq3-based organic light-emitting diodes at room temperature

Science.gov (United States)

Zhang, Tingting; Holford, D. F.; Gu, Hang; Kreouzis, T.; Zhang, Sijie; Gillin, W. P.

2016-01-01

The magnetic field effects on the electroluminescence of aluminium tris-(8-hydroxyqinoline) (Alq3) based organic light emitting diodes have been investigated by varying the electron/hole ratio in the emissive layer. Experimental results reveal that a negative high field effect in the magneto-electroluminescence (MEL) can be found in devices with very low triplet exciton concentration at room temperature. This suggests triplet-triplet annihilation cannot be used to explain the negative high field MEL in the Alq3 system. Our results suggest that hole-exciton interaction may be the origin of the negative high field MEL and also, in parallel with this interaction, there is also the more common positive high field process occurring which has been tentatively attributed to electron-exciton interactions. The competition between these different processes decides the final shape of the MEL at high fields.

Electrophoretic characterization of protein interactions suggesting limited feasibility of accelerated shelf-life testing of ultra-high temperature milk.

Science.gov (United States)

Grewal, Manpreet Kaur; Chandrapala, Jayani; Donkor, Osaana; Apostolopoulos, Vasso; Vasiljevic, Todor

2017-01-01

Accelerated shelf-life testing is applied to a variety of products to estimate keeping quality over a short period of time. The industry has not been successful in applying this approach to ultra-high temperature (UHT) milk because of chemical and physical changes in the milk proteins that take place during processing and storage. We investigated these protein changes, applying accelerated shelf-life principles to UHT milk samples with different fat levels and using native- and sodium dodecyl sulfate-PAGE. Samples of UHT skim and whole milk were stored at 20, 30, 40, and 50°C for 28d. Irrespective of fat content, UHT treatment had a similar effect on the electrophoretic patterns of milk proteins. At the start of testing, proteins were bonded mainly through disulfide and noncovalent interactions. However, storage at and above 30°C enhanced protein aggregation via covalent interactions. The extent of aggregation appeared to be influenced by fat content; whole milk contained more fat than skim milk, implying aggregation via melted or oxidized fat, or both. Based on reduction in loss in absolute quantity of individual proteins, covalent crosslinking in whole milk was facilitated mainly by products of lipid oxidation and increased access to caseins for crosslinking reactions. Maillard and dehydroalanine products were the main contributors involved in protein changes in skim milk. Protein crosslinking appeared to follow a different pathway at higher temperatures (≥40°C) than at lower temperatures, making it very difficult to extrapolate these changes to protein interactions at lower temperatures. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Chemical interactions between as-received and pre-oxidized Zircaloy-4 and Inconel-718 at high temperatures

International Nuclear Information System (INIS)

Hofmann, P.; Markiewicz, M.

1994-06-01

Isothermal reaction experiments were performed in the temperature range of 1000 - 1300 C in order to determine the chemical interactions between Zircaloy-4 fuel rod cladding and Inconel-718 spacer grids of Pressurized Water Reactors (PWR) under severe accident conditions. It was not possible to apply even higher temperatures since fast and complete liquefaction of the components occurred as a result of eutectic interactions during heatup. The liquid reaction products formed enhance and accelerate the degradation of the material couples and the fuel elements, respectively. Only small amounts of Inconel are necessary to liquefy large amounts of Zircaloy. Thin oxide layers on the Zircaloy surface delay the beginning of the chemical interactions with Inconel but cannot prevent them. In this work the reaction kinetics have been determined for the system: as-received and pre-oxidized Zircaloy-4/Inconel 718. The interactions can be described by parabolic rate laws; the Arrhenius equations for the various interactions are given. (orig.) [de

High temperature interaction studies on equimolar nitrate mixture of uranyl nitrate hexahydrate and gadolinium nitrate hexahydrate

International Nuclear Information System (INIS)

Kalekar, Bhupesh B.; Raje, Naina; Reddy, A.V.R.

2015-01-01

Rare earths including gadolinium form a sizeable fraction of the fission products in the nuclear fission of fissile material in the reactor. These fission products can interact with uranium dioxide fuel and can form various compounds which can alter the thermal behavior of the fuel. The mixed oxide formed due to the high temperature interactions of mixture of uranyl nitrate hexahydrate (UNH) and gadolinium nitrate hexahydrate (GdNH) has been studied using thermal and X- ray diffraction techniques. The equimolar mixture of UNH and GdNH was prepared by mixing the weighed amount of individual nitrates and grinding gently with mortar and pestle. Thermogravimetry (TG) measurements were carried out by separately heating 100 mg of mixture and individual nitrates at heating rate of 10°C min -1 using Netzsch thermal analyzer (Model No.: STA 409 PC Luxx) in high purity nitrogen atmosphere with a flow rate of 120 mL min -1 . The XRD measurement was carried out on a Philips X-ray diffractometer (Model PW1710) using nickel-filtered Cu-Kα radiation

High Temperature Creep-Fatigue-Oxidation Interactions in 9% Cr Martensitic Steels

International Nuclear Information System (INIS)

Fournier, B.; Sauzay, M.; Pineau, A.

2007-01-01

Full text of publication follows: Martensitic steels of the 9-12%Cr family are widely used in the energy industry and were selected as candidate materials for structural components of future fusion reactors [1,2]. Typical in-service conditions require operating temperatures between 673 and 873 K, which means that the creep behaviour of these steels is of primary interest. In addition, some components are anticipated to operate in a pulsed mode, leading to complex time-dependencies of temperature, stress and strain in materials. Therefore, in design procedures, fatigue and creep-fatigue data are required. Furthermore, to meet the need for very long inservice lifetime of components (with very long hold times ∼ one month) reliable cyclic lifetime models are necessary, since complete tests with such long holding periods cannot, of course, be carried out in laboratory. To make these extrapolations safer and more reliable a precise understanding of the damage and interaction mechanisms is required. Fatigue, creep-fatigue and relaxation-fatigue tests were carried out at high temperature (823 K), under three different atmospheres (air, vacuum and He+impurities) and for a large panel of applied fatigue and creep strain. Holding periods are found to decrease the fatigue lifetime. Surprisingly enough compressive holding periods are more deleterious than tensile ones in air. Observations were carried out on fracture surfaces, specimen surfaces and cross sections. No creep cavity is visible, whatever the holding period duration, but a major influence of oxidation is highlighted. Oxidation is all the more predominant for low applied strains. Tests carried out under vacuum and helium show that the formation of a thick oxide layer can lead to a fatigue lifetime 4 times shorter. Crack propagation is mainly transgranular for all applied strains. Both damage observations and a theoretical study of oxide layers fracture mechanisms allow qualitative explanations for recorded fatigue

Hole-exciton interaction induced high field decay of magneto-electroluminescence in Alq{sub 3}-based organic light-emitting diodes at room temperature

Energy Technology Data Exchange (ETDEWEB)

Zhang, Tingting; Holford, D. F.; Gu, Hang; Kreouzis, T. [Materials Research Institute and School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); Zhang, Sijie, E-mail: Sijie.zhang@scu.edu.cn, E-mail: w.gillin@qmul.ac.uk [College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China); Gillin, W. P., E-mail: Sijie.zhang@scu.edu.cn, E-mail: w.gillin@qmul.ac.uk [Materials Research Institute and School of Physics and Astronomy, Queen Mary University of London, Mile End Road, London E1 4NS (United Kingdom); College of Physical Science and Technology, Sichuan University, Chengdu 610064 (China)

2016-01-11

The magnetic field effects on the electroluminescence of aluminium tris-(8-hydroxyqinoline) (Alq{sub 3}) based organic light emitting diodes have been investigated by varying the electron/hole ratio in the emissive layer. Experimental results reveal that a negative high field effect in the magneto-electroluminescence (MEL) can be found in devices with very low triplet exciton concentration at room temperature. This suggests triplet-triplet annihilation cannot be used to explain the negative high field MEL in the Alq{sub 3} system. Our results suggest that hole-exciton interaction may be the origin of the negative high field MEL and also, in parallel with this interaction, there is also the more common positive high field process occurring which has been tentatively attributed to electron-exciton interactions. The competition between these different processes decides the final shape of the MEL at high fields.

Propagation of sound wave in high density deuterium at high temperatures

International Nuclear Information System (INIS)

Inoue, Kazuko; Ariyasu, Tomio

1986-01-01

The velocity and the attenuation constant of sound wave have been calculated for high density (10 24 ∼ 10 27 /cm 3 ) deuterium at high temperatures (10 -1 ∼ 10 4 eV). This calculation was made to understand the fuel properties in inertial confinement fusion and to obtain the basic data for pellet design. The isentropic sound wave which propagates in deuterium in plasma state at temperature T i = T e , is dealt with. The velocity is derived using the modulus of bulk elasticity of the whole system and the modulus of shear elasticity due to ion-ion interaction. For the calculation of attenuation constant, the bulk and shear viscosity due to ion-ion interaction, the shear viscosity of free electron gas, and the thermal conductivity due to free electrons are considered. The condition of frequency for the existence of such isentropic sound wave is discussed. The possibility of penetration into the fuel pellet in inertial confinement fusion is also discussed. The followings have been found: (1) The sound velocity is determined mainly from the bulk elasticity. The contribution of the shear elasticity is small. The velocity ranges from 2.8 x 10 6 to 1.5 x 10 8 cm/s in the above mentioned temperature and density regions. (2) The coefficient of attenuation constant with respect to ω 2 /2ρu 3 plotted versus temperature with the parameter of density shows a minimum. At temperatures below this minimum, the attenuation comes mainly from the bulk viscosity due to ion-ion interaction and the shear viscosity due to free electron gas. At temperatures above this minimum, the sound is attenuated mainly by the thermal conductivity due to electrons. (3) The condition for the existence of such adiabatic sound wave, is satisfied with the frequency less than 10 10 Hz. But, as for the pellet design, the wave length of sound with frequency less than 10 10 Hz is longer than the diameter of pellet when compressed highly. (author)

Low-energy physics of high-temperature superconductors

International Nuclear Information System (INIS)

Emery, V.J.; Kivelson, S.A.

1992-01-01

It is argued that the low-energy properties of high temperature superconductors are dominated by the interaction between the mobile holes and a particular class of collective modes, corresponding to local large-amplitude low-energy fluctuations in the hole density. The latter are a consequence of the competition between the effects of long-range Coulomb interactions and the tendency of a low concentration of holes in an antiferromagnet to phase separate. The low-energy behavior of the system is governed by the same fixed point as the two-channel Kondo problem, which accounts for the ''universality'' of the properties of the cuprate superconductors. Predictions of the optical properties and the spin dynamics are compared with experiment. The pairing resonance of the two Kondo problem gives a mechanism of high temperature superconductivity with an unconventional symmetry of the order parameter

The mean and variance of environmental temperature interact to determine physiological tolerance and fitness.

Science.gov (United States)

Bozinovic, Francisco; Bastías, Daniel A; Boher, Francisca; Clavijo-Baquet, Sabrina; Estay, Sergio A; Angilletta, Michael J

2011-01-01

Global climate change poses one of the greatest threats to biodiversity. Most analyses of the potential biological impacts have focused on changes in mean temperature, but changes in thermal variance will also impact organisms and populations. We assessed the combined effects of the mean and variance of temperature on thermal tolerances, organismal survival, and population growth in Drosophila melanogaster. Because the performance of ectotherms relates nonlinearly to temperature, we predicted that responses to thermal variation (±0° or ±5°C) would depend on the mean temperature (17° or 24°C). Consistent with our prediction, thermal variation enhanced the rate of population growth (r(max)) at a low mean temperature but depressed this rate at a high mean temperature. The interactive effect on fitness occurred despite the fact that flies improved their heat and cold tolerances through acclimation to thermal conditions. Flies exposed to a high mean and a high variance of temperature recovered from heat coma faster and survived heat exposure better than did flies that developed at other conditions. Relatively high survival following heat exposure was associated with low survival following cold exposure. Recovery from chill coma was affected primarily by the mean temperature; flies acclimated to a low mean temperature recovered much faster than did flies acclimated to a high mean temperature. To develop more realistic predictions about the biological impacts of climate change, one must consider the interactions between the mean environmental temperature and the variance of environmental temperature.

High temperature transient deformation of mixed oxide fuels

International Nuclear Information System (INIS)

Slagle, O.D.

1986-01-01

The purpose of this paper is to present recent experimental results on fuel creep under transient conditions at high temperatures. The effect of temperature, stress, heating rate, density and grain size were considered. An empirical formulation is derived for the relationship between strain, stress, temperature and heating rate. This relationship provides a means for incorporating stress relief into the analysis of fuel-cladding interaction during an overpower transient. The effect of sample density and initial grain size is considered by varying the sample parameters. Previously derived steady-state creep relationships for the high temperature creep of mixed oxide fuel were combined with the time dependency of creep found for UO 2 to calculate a transient creep relationship for mixed oxide fuel. These calculated results were found to be in good agreement with the measured high temperature transient creep results

The Fermion boson interaction within the linear sigma model at finite temperature

International Nuclear Information System (INIS)

Caldas, H.C.G.

2000-01-01

We study the interaction of massless bosons at finite temperature. Specifically, we calculate the self-energy of massless fermions due to interaction with massless bosons at high temperature, which is the region where thermal effects are maximal. The calculations are concentrated in the limit of vanishing fermion three momentum and after considering the effective boson dressed mass, we obtain the damping rate of the fermion. It is shown that in the limit k O 2 T + g 3 T. (author)

High temperature degradation in power plants and refineries

Directory of Open Access Journals (Sweden)

Furtado Heloisa Cunha

2004-01-01

Full Text Available Thermal power plants and refineries around the world share many of the same problems, namely aging equipment, high costs of replacement, and the need to produce more efficiently while being increasingly concerned with issues of safety and reliability. For equipment operating at high temperature, there are many different mechanisms of degradation, some of which interact, and the rate of accumulation of damage is not simple to predict. The paper discusses the mechanisms of degradation at high temperature and methods of assessment of such damage and of the remaining safe life for operation.

High temperature creep-fatigue design

International Nuclear Information System (INIS)

Tavassoli, A. A. F.; Fournier, B.; Sauzay, M.

2010-01-01

Generation IV fission and future fusion reactors envisage development of more efficient high temperature concepts where materials performances are key to their success. This paper examines different types of high temperature creep-fatigue interactions and their implications on design rules for the structural materials retained in both programmes. More precisely, the paper examines current status of design rules for the stainless steel type 316L(N), the conventional Modified 9Cr-1Mo martensitic steel and the low activation Eurofer steel. Results obtained from extensive high temperature creep, fatigue and creep-fatigue tests performed on these materials and their welded joints are presented. These include sequential creep-fatigue and relaxation creep-fatigue tests with hold times in tension, in compression or in both. Effects of larger plastic deformations on fatigue properties are studied through cyclic creep tests or fatigue tests with extended hold time in creep. In most cases, mechanical test results are accompanied with microstructural and fractographic observations. In the case of martensitic steels, the effect of oxidation is examined by performing creep-fatigue tests on identical specimens in vacuum. Results obtained are analyzed and their implications on design allowable and creep-fatigue interaction diagrams are presented. While reasonable confidence is found in predicting creep-fatigue damage through existing code procedures for austenitic stainless steels, effects of cyclic softening and coarsening of microstructure of martensitic steels throughout the fatigue life on materials properties need to be taken into account for more precise damage calculations. In the long-term, development of ferritic/martensitic steels with stable microstructure, such as ODS steels, is proposed. (authors)

High temperature creep-fatigue design

Energy Technology Data Exchange (ETDEWEB)

Tavassoli, A. A. F.; Fournier, B.; Sauzay, M. [CEA Saclay, DEN DMN, F-91191 Gif Sur Yvette (France)

2010-07-01

Generation IV fission and future fusion reactors envisage development of more efficient high temperature concepts where materials performances are key to their success. This paper examines different types of high temperature creep-fatigue interactions and their implications on design rules for the structural materials retained in both programmes. More precisely, the paper examines current status of design rules for the stainless steel type 316L(N), the conventional Modified 9Cr-1Mo martensitic steel and the low activation Eurofer steel. Results obtained from extensive high temperature creep, fatigue and creep-fatigue tests performed on these materials and their welded joints are presented. These include sequential creep-fatigue and relaxation creep-fatigue tests with hold times in tension, in compression or in both. Effects of larger plastic deformations on fatigue properties are studied through cyclic creep tests or fatigue tests with extended hold time in creep. In most cases, mechanical test results are accompanied with microstructural and fractographic observations. In the case of martensitic steels, the effect of oxidation is examined by performing creep-fatigue tests on identical specimens in vacuum. Results obtained are analyzed and their implications on design allowable and creep-fatigue interaction diagrams are presented. While reasonable confidence is found in predicting creep-fatigue damage through existing code procedures for austenitic stainless steels, effects of cyclic softening and coarsening of microstructure of martensitic steels throughout the fatigue life on materials properties need to be taken into account for more precise damage calculations. In the long-term, development of ferritic/martensitic steels with stable microstructure, such as ODS steels, is proposed. (authors)

Interactive effects of ambient temperature and light sources at high relative humidity on growth performance and blood physiological variables in broilers grown to 42 day of age

Science.gov (United States)

The interactive effects of ambient temperature and light sources at high relative humidity on growth performance and blood physiological reactions in broilers grown to 42 day of age were investigated. The experiment consisted of 2 levels (Moderate=21.1, High=26.7 °C) of temperatures and 2 light sour...

Gas phase analysis of CO interactions with solid surfaces at high temperatures

International Nuclear Information System (INIS)

Anghel, Clara; Hoernlund, Erik; Hultquist, Gunnar; Limbaeck, Magnus

2004-01-01

An in situ method including mass spectrometry and labeled gases is presented and used to gain information on adsorption of molecules at high temperatures (>300 deg. C). Isotopic exchange rate in H 2 upon exposure to an oxidized zicaloy-2 sample and exchange rate in CO upon exposure to various materials have been measured. From these measurements, molecular dissociation rates in respective system have been calculated. The influence of CO and N 2 on the uptake rate of H 2 in zirconium and oxidized zicaloy-2 is discussed in terms of tendency for adsorption at high temperatures. In the case of oxidized Cr exposed to CO gas with 12 C, 13 C, 16 O and 18 O, the influence of H 2 O is investigated with respect to dissociation of CO molecules. The presented data supports a view of different tendencies for molecular adsorption of H 2 O, CO, N 2 , and H 2 molecules on surfaces at high temperatures

Universal contact of strongly interacting fermions at finite temperatures

Energy Technology Data Exchange (ETDEWEB)

Hu Hui; Liu Xiaji; Drummond, Peter D, E-mail: hhu@swin.edu.au, E-mail: xiajiliu@swin.edu.au, E-mail: pdrummond@swin.edu.au [ARC Centre of Excellence for Quantum-Atom Optics, Centre for Atom Optics and Ultrafast Spectroscopy, Swinburne University of Technology, Melbourne 3122 (Australia)

2011-03-15

The recently discovered universal thermodynamic behavior of dilute, strongly interacting Fermi gases also implies a universal structure in the many-body pair-correlation function at short distances, as quantified by the contact I. Here, we theoretically calculate the temperature dependence of this universal contact for a Fermi gas in free space and in a harmonic trap. At high temperatures above the Fermi degeneracy temperature, T{approx}>T{sub F}, we obtain a reliable non-perturbative quantum virial expansion up to third order. At low temperatures, we compare different approximate strong-coupling theories. These make different predictions, which need to be tested either by future experiments or by advanced quantum Monte Carlo simulations. We conjecture that in the universal unitarity limit, the contact or correlation decreases monotonically with increasing temperature, unless the temperature is significantly lower than the critical temperature, T<

High temperature equation of state of metallic hydrogen

International Nuclear Information System (INIS)

Shvets, V. T.

2007-01-01

The equation of state of liquid metallic hydrogen is solved numerically. Investigations are carried out at temperatures from 3000 to 20 000 K and densities from 0.2 to 3 mol/cm 3 , which correspond both to the experimental conditions under which metallic hydrogen is produced on earth and the conditions in the cores of giant planets of the solar system such as Jupiter and Saturn. It is assumed that hydrogen is in an atomic state and all its electrons are collectivized. Perturbation theory in the electron-proton interaction is applied to determine the thermodynamic potentials of metallic hydrogen. The electron subsystem is considered in the randomphase approximation with regard to the exchange interaction and the correlation of electrons in the local-field approximation. The proton-proton interaction is taken into account in the hard-spheres approximation. The thermodynamic characteristics of metallic hydrogen are calculated with regard to the zero-, second-, and third-order perturbation theory terms. The third-order term proves to be rather essential at moderately high temperatures and densities, although it is much smaller than the second-order term. The thermodynamic potentials of metallic hydrogen are monotonically increasing functions of density and temperature. The values of pressure for the temperatures and pressures that are characteristic of the conditions under which metallic hydrogen is produced on earth coincide with the corresponding values reported by the discoverers of metallic hydrogen to a high degree of accuracy. The temperature and density ranges are found in which there exists a liquid phase of metallic hydrogen

Atomic processes in high temperature plasmas

International Nuclear Information System (INIS)

Hahn, Y.

1990-03-01

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

High-temperature in-situ TEM straining of the interaction with dislocations and particles for Cu-added ferritic stainless steel.

Science.gov (United States)

Kobayashi, Shuhei; Kaneko, Kenji; Yamada, Kazuhiro; Kikuchi, Masao; Kanno, Norihiro; Hamada, Junichi

2014-11-01

IntroductionCu is always present in the matrix when ferritic steels were prepared from ferrous scrap. When the ferritic steels are aged thermally, Cu precipitates start appear and disperse finely and homogeneously [1], which may make the steels strengthened by precipitation hardening. In this study, the interaction between Cu precipitates and dislocations was exmined via high-temperature in-situ TEM straining. ExperimentalCu-added ferritic stainless steel (Fe-18.4%Cr-1.5%Cu) was used in the present study. Specimen was aged at1073 K for 360 ks. Samples for TEM observation were prepared by focused ion beam (FIB; Quanta 3D 200i) method. Microstructure of specimen was analyzed by JEM-3200FSK and high-temperature in-situ TEM straining was conducted using JEM-1300NEF. Results and discussionInteraction between Cu precipitates and dislocation is seen from consecutive TEM images acquired by in-situ TEM straining at 1073 K, as shown in Fig.1. The size of Cu precipitates was about 70 nm and several dislocations were present within the field of view. In particular, progressing dislocations contacted with the Cu precipitate at right angle, as indicated by arrows in Fig.1 (b) to (d). This result implies that there is an attractive interaction between dislocations and the Cu precipitate. This is attributed to the fact that Stress field of dislocations was easily relaxed in interface between the Cu precipitate and matrix because of lattice and interface diffusion as well as slip in the interface [2,3]. Furthermore, dislocations pass through the particle after contacting it, so that the interaction with dislocations and particles should be explained by Srolovitz mechanism [4].jmicro;63/suppl_1/i28/DFU083F1F1DFU083F1Fig. 1.TEM images foucused on interaction with dislocations and partticles. © The Author 2014. Published by Oxford University Press on behalf of The Japanese Society of Microscopy. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

Interactions between temperature and nutrients across levels of ecological organization.

Science.gov (United States)

Cross, Wyatt F; Hood, James M; Benstead, Jonathan P; Huryn, Alexander D; Nelson, Daniel

2015-03-01

Temperature and nutrient availability play key roles in controlling the pathways and rates at which energy and materials move through ecosystems. These factors have also changed dramatically on Earth over the past century as human activities have intensified. Although significant effort has been devoted to understanding the role of temperature and nutrients in isolation, less is known about how these two factors interact to influence ecological processes. Recent advances in ecological stoichiometry and metabolic ecology provide a useful framework for making progress in this area, but conceptual synthesis and review are needed to help catalyze additional research. Here, we examine known and potential interactions between temperature and nutrients from a variety of physiological, community, and ecosystem perspectives. We first review patterns at the level of the individual, focusing on four traits--growth, respiration, body size, and elemental content--that should theoretically govern how temperature and nutrients interact to influence higher levels of biological organization. We next explore the interactive effects of temperature and nutrients on populations, communities, and food webs by synthesizing information related to community size spectra, biomass distributions, and elemental composition. We use metabolic theory to make predictions about how population-level secondary production should respond to interactions between temperature and resource supply, setting up qualitative predictions about the flows of energy and materials through metazoan food webs. Last, we examine how temperature-nutrient interactions influence processes at the whole-ecosystem level, focusing on apparent vs. intrinsic activation energies of ecosystem processes, how to represent temperature-nutrient interactions in ecosystem models, and patterns with respect to nutrient uptake and organic matter decomposition. We conclude that a better understanding of interactions between temperature and

Structural analysis technology for high-temperature design

International Nuclear Information System (INIS)

Greenstreet, W.L.

1977-01-01

Results from an ongoing program devoted to the development of verified high-temperature structural design technology applicable to nuclear reactor systems are described. The major aspects addressed by the program are (1) deformation behavior; (2) failure associated with creep rupture, brittle fracture, fatigue, creep-fatigue interactions, and crack propagation; and (3) the establishment of appropriate design criteria. This paper discusses information developed in the deformation behavior category. The material considered is type 304 stainless steel, and the temperatures range to 1100 0 F (593 0 C). In essence, the paper considers the ingredients necessary for predicting relatively high-temperature inelastic deformation behavior of engineering structures under time-varying temperature and load conditions and gives some examples. These examples illustrate the utility and acceptability of the computational methods identified and developed for prediting essential features of complex inelastic behaviors. Conditions and responses that can be encountered under nuclear reactor service conditions and invoked in the examples. (Auth.)

The muon spin response to intermittent hyperfine interaction: modelling the high-temperature electrical activity of hydrogen in silicon

International Nuclear Information System (INIS)

Lord, J S; Cox, S F J; Charlton, M; Werf, D P Van der; Lichti, R L; Amato, A

2004-01-01

At temperatures above 600 K in silicon, unlike at lower temperatures, the partitioning of muonium between its neutral paramagnetic states and its charged or electronically diamagnetic states corresponds closely to thermodynamic equilibrium. The individual charge states are short lived, with many cycles of carrier capture and release occurring within the muon lifetime. The resultant intermittent hyperfine interaction depolarizes the muons strongly, with longitudinal and transverse relaxation rates remaining distinct up to about 700 K but becoming equal at still higher temperatures. Data up to 900 K are presented and interpreted. The muon spin rotation spectrum in transverse magnetic fields, although collapsed to a single broad line in this charge exchange regime, is shifted substantially from the muon Larmor frequency, the shift being non-linear in field and only in small part due to electron polarization. A new density matrix treatment shows how all three observables can be accounted for with a consistent set of transition rates. These in turn may be interpreted in terms of effective donor and acceptor energy levels appropriate to this high-temperature regime, confirming negative-U behaviour and providing the first estimate, for muonium, of this elusive parameter. At temperatures where passivation complexes are dissociated, these findings provide a guide to, and microscopic models for, the electrical activity of hydrogen

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

Effects of CO2 and temperature on tritrophic interactions.

Directory of Open Access Journals (Sweden)

Lee A Dyer

Full Text Available There has been a significant increase in studies of how global change parameters affect interacting species or entire communities, yet the combined or interactive effects of increased atmospheric CO2 and associated increases in global mean temperatures on chemically mediated trophic interactions are mostly unknown. Thus, predictions of climate-induced changes on plant-insect interactions are still based primarily on studies of individual species, individual global change parameters, pairwise interactions, or parameters that summarize communities. A clear understanding of community response to global change will only emerge from studies that examine effects of multiple variables on biotic interactions. We examined the effects of increased CO2 and temperature on simple laboratory communities of interacting alfalfa, chemical defense, armyworm caterpillars, and parasitoid wasps. Higher temperatures and CO2 caused decreased plant quality, decreased caterpillar development times, developmental asynchrony between caterpillars and wasps, and complete wasp mortality. The effects measured here, along with other effects of global change on natural enemies suggest that biological control and other top-down effects of insect predators will decline over the coming decades.

Nuclear and quark matter at high temperature

Energy Technology Data Exchange (ETDEWEB)

Biro, Tamas S. [H.A.S. Wigner Research Centre for Physics, Budapest (Hungary); Jakovac, Antal [Roland Eotvos University, Budapest (Hungary); Schram, Zsolt [University of Debrecen, Institute for Theoretical Physics, Debrecen (Hungary)

2017-03-15

We review important ideas on nuclear and quark matter description on the basis of high-temperature field theory concepts, like resummation, dimensional reduction, interaction scale separation and spectral function modification in media. Statistical and thermodynamical concepts are spotted in the light of these methods concentrating on the -partially still open- problems of the hadronization process. (orig.)

The Fermion boson interaction within the linear sigma model at finite temperature

Energy Technology Data Exchange (ETDEWEB)

Caldas, H.C.G. [Fundacao de Ensino Superior de Sao Joao del Rei (FUNREI), MG (Brazil). Dept. de Ciencias Naturais (DCNAT)

2000-07-01

We study the interaction of massless bosons at finite temperature. Specifically, we calculate the self-energy of massless fermions due to interaction with massless bosons at high temperature, which is the region where thermal effects are maximal. The calculations are concentrated in the limit of vanishing fermion three momentum and after considering the effective boson dressed mass, we obtain the damping rate of the fermion. It is shown that in the limit k{sub O} <

Finite temperature system of strongly interacting baryons

International Nuclear Information System (INIS)

Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.; Wheeler, J.W.

1976-07-01

A fully relativistic finite temperature many body theory is constructed and used to examine the bulk properties of a system of strongly interacting baryons. The strong interactions are described by a two parameter phenomenological model fit to a simple description of nuclear matter at T = 0. The zero temperature equation of state for such a system which has already been discussed in the literature was developed to give a realistic description of nuclear matter. The model presented here is the exact finite temperature extension of that model. The effect of the inclusion of baryon pairs for T greater than or equal to 2mc 2 /k is discussed in detail. The phase transition identified with nuclear matter vanishes for system temperatures in excess of T/sub C/ = 1.034 x 10 11 0 K. All values of epsilon (P,T) correspond to systems that are causal in the sense that the locally determined speed of sound never exceeds the speed of light

Finite temperature system of strongly interacting baryons

Energy Technology Data Exchange (ETDEWEB)

Bowers, R.L.; Gleeson, A.M.; Pedigo, R.D.; Wheeler, J.W.

1976-07-01

A fully relativistic finite temperature many body theory is constructed and used to examine the bulk properties of a system of strongly interacting baryons. The strong interactions are described by a two parameter phenomenological model fit to a simple description of nuclear matter at T = 0. The zero temperature equation of state for such a system which has already been discussed in the literature was developed to give a realistic description of nuclear matter. The model presented here is the exact finite temperature extension of that model. The effect of the inclusion of baryon pairs for T greater than or equal to 2mc/sup 2//k is discussed in detail. The phase transition identified with nuclear matter vanishes for system temperatures in excess of T/sub C/ = 1.034 x 10/sup 11/ /sup 0/K. All values of epsilon (P,T) correspond to systems that are causal in the sense that the locally determined speed of sound never exceeds the speed of light.

The influence of high temperatures on milk proteins

Directory of Open Access Journals (Sweden)

Maćej Ognjen D.

2002-01-01

Full Text Available High temperatures Induce certain changes in milk constituents, but the degree of these changes depends on both the temperature and time of heat treatment. The most pronounced changes take place in milk proteins. The forewarming of milk causes an increase in acidity, the precipitation of soluble Ca-phosphate, whey protein denaturation and coagulation, as well as the interaction with casein micelles, the Maillard browning reaction, the dephosphorylation of casein, the hydrolysis of casein micelles, changes in whey proteins, an extension of the rennet coagulation time and an exchange of the rheological properties of the acid and rennet casein gels, changes in the zeta-potential and casein micelle hydration, the interaction between the milk proteins and proteins of milk fat globule membrane.

Proceedings, phenomenology and applications of high temperature superconductors

International Nuclear Information System (INIS)

Bedell, K.S.

1991-01-01

Phenomenology and Applications of High Temperature Superconductors, The Los Alamos Symposium: 1991, was sponsored by the Los Alamos National Laboratory, Center for Materials Science, the Advanced Studies Program on High Temperature Superconductivity Theory (ASP) and the Exploratory Research and Development Center. This is the second symposium in the series. High Temperature Superconductivity, The Los Alamos Symposium: 1989, also published by Addison Wesley, focused on the cutting-edge theoretical and experimental issues in high temperature superconductors. This symposium, with its focus on the phenomenology and applications of high temperature superconductors, gives a complementary review of the aspects of the field closely related to the impact of high temperature superconductors on technology. The objective of ASP is to advance the field on a broad front with no specific point of view by bringing a team of leading academic theorists into a joint effort with the theoretical and experimental scientists of a major DOE national laboratory. The ASP consisted of fellows led by Robert Schrieffer (UCSB and now FSU) joined by David Pines (University of illinois), Elihu Abrahams (Rutgers), Sebastian Doniach (Stanford), and Maurice Rice (ETH, Zurich) and theoretical and experimental staff of Los Alamos National Laboratory. This synergism of academic, laboratory, theoretical and experimental research produced a level of interaction and excitement that would not be possible otherwise. This publication and the previous one in the series are just examples of how this approach to advancing science can achieve significant contributions

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.

Theory of high-T{sub C} superconductivity: transition temperature

Energy Technology Data Exchange (ETDEWEB)

Harshman, Dale R [Physikon Research Corporation, Lynden, WA 98264 (United States); Fiory, Anthony T [Department of Physics, New Jersey Institute of Technology, Newark, NJ 07102 (United States); Dow, John D, E-mail: drh@physikon.net [Department of Physics, Arizona State University, Tempe, AZ 85287 (United States)

2011-07-27

It is demonstrated that the transition temperature (T{sub C}) of high-T{sub C} superconductors is determined by their layered crystal structure, bond lengths, valency properties of the ions, and Coulomb coupling between electronic bands in adjacent, spatially separated layers. Analysis of 31 high-T{sub C} materials (cuprates, ruthenates, ruthenocuprates, iron pnictides, organics) yields the universal relationship for optimal compounds, k{sub B}T{sub C0} ={beta}/{iota}{zeta}, where {iota} is related to the mean spacing between interacting charges in the layers, {zeta} is the distance between interacting electronic layers, {beta} is a universal constant and T{sub C0} is the optimal transition temperature (determined to within an uncertainty of {+-} 1.4 K by this relationship). Non-optimum compounds, in which sample degradation is evident, e.g. by broadened superconducting transitions and diminished Meissner fractions, typically exhibit reduced T{sub C} < T{sub C0}. It is shown that T{sub C0} may be obtained from an average of the Coulomb interaction forces between the two layers.

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...

The Born-Mayer-Huggins potential in high temperature superconductors

Science.gov (United States)

Singh, Hempal; Singh, Anu; Indu, B. D.

2016-07-01

The Born-Mayer-Huggins potential which has been found the best suitable potential to study the YBa2Cu3O7-δ type high temperature superconductors is revisited in a new framework. A deeper insight in it reveals that the Born-Mayer parameters for different interactions in high temperature superconductor are not simple quantities but several thermodynamic and spatial functions enter the problem. Based on the new theory, the expressions for pressure, bulk modulus and Born-Mayer parameters have been derived and it is established that these quantities depend upon Gruneisen parameter which is the measure of the strength of anharmonic effects in high temperature superconductors. This theory has been applied to a specific model YBa2Cu3O7-δ crystal for the purpose of numerical estimates to justify the new results.

High pressure neutron and X-ray diffraction at low temperatures

Energy Technology Data Exchange (ETDEWEB)

Ridley, Christopher J.; Kamenev, Konstantin V. [Edinburgh Univ. (United Kingdom). School of Engineering and the Centre for Science at Extreme Conditions

2014-04-01

This paper presents a review of techniques and considerations in the design and construction of high pressure, low temperature diffraction experiments. Also intended as an introductory text to new high pressure users, the crucial aspects of pressure cell design are covered. The general classification of common designs, and a discussion into the key beam interaction, mechanical, and thermal properties of commonly used materials is given. The advantages of different materials and high pressure cell classifications are discussed, and examples of designs developed for low temperature diffraction studies are presented, and compared. (orig.)

High pressure neutron and X-ray diffraction at low temperatures

International Nuclear Information System (INIS)

Ridley, Christopher J.; Kamenev, Konstantin V.

2014-01-01

This paper presents a review of techniques and considerations in the design and construction of high pressure, low temperature diffraction experiments. Also intended as an introductory text to new high pressure users, the crucial aspects of pressure cell design are covered. The general classification of common designs, and a discussion into the key beam interaction, mechanical, and thermal properties of commonly used materials is given. The advantages of different materials and high pressure cell classifications are discussed, and examples of designs developed for low temperature diffraction studies are presented, and compared. (orig.)

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...... internal resistance of the cell, and long-term stable, it is critical to develop electrode materials that are optimal for steam electrolysis. In this article electrolysis cells for electrolysis of water or steam at temperatures above 200 degrees C for production of H-2 are reviewed. High temperature...... 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...

High temperature, oxygen, and performance: Insights from reptiles and amphibians.

Science.gov (United States)

Gangloff, Eric J; Telemeco, Rory S

2018-04-25

Much recent theoretical and empirical work has sought to describe the physiological mechanisms underlying thermal tolerance in animals. Leading hypotheses can be broadly divided into two categories that primarily differ in organizational scale: 1) high temperature directly reduces the function of subcellular machinery, such as enzymes and cell membranes, or 2) high temperature disrupts system-level interactions, such as mismatches in the supply and demand of oxygen, prior to having any direct negative effect on the subcellular machinery. Nonetheless, a general framework describing the contexts under which either subcellular component or organ system failure limits organisms at high temperatures remains elusive. With this commentary, we leverage decades of research on the physiology of ectothermic tetrapods (amphibians and non-avian reptiles) to address these hypotheses. Available data suggest both mechanisms are important. Thus, we expand previous work and propose the Hierarchical Mechanisms of Thermal Limitation (HMTL) hypothesis, which explains how subcellular and organ system failures interact to limit performance and set tolerance limits at high temperatures. We further integrate this framework with the thermal performance curve paradigm commonly used to predict the effects of thermal environments on performance and fitness. The HMTL framework appears to successfully explain diverse observations in reptiles and amphibians and makes numerous predictions that remain untested. We hope that this framework spurs further research in diverse taxa and facilitates mechanistic forecasts of biological responses to climate change.

Interactive short-term effects of equivalent temperature and air pollution on human mortality in Berlin and Lisbon

International Nuclear Information System (INIS)

Burkart, Katrin; Canário, Paulo; Breitner, Susanne; Schneider, Alexandra; Scherber, Katharina; Andrade, Henrique; Alcoforado, Maria João; Endlicher, Wilfried

2013-01-01

There is substantial evidence that both temperature and air pollution are predictors of mortality. Thus far, few studies have focused on the potential interactive effects between the thermal environment and different measures of air pollution. Such interactions, however, are biologically plausible, as (extreme) temperature or increased air pollution might make individuals more susceptible to the effects of each respective predictor. This study investigated the interactive effects between equivalent temperature and air pollution (ozone and particulate matter) in Berlin (Germany) and Lisbon (Portugal) using different types of Poisson regression models. The findings suggest that interactive effects exist between air pollutants and equivalent temperature. Bivariate response surface models and generalised additive models (GAMs) including interaction terms showed an increased risk of mortality during periods of elevated equivalent temperatures and air pollution. Cold effects were mostly unaffected by air pollution. The study underscores the importance of air pollution control in mitigating heat effects. -- Highlights: • Interactive effects between air pollution and equivalent temperature result in augmented excess mortality. • High levels of ozone and particulate matter increase adverse heat effects on human mortality. • Cold effects are mostly unaffected by air pollution. • Findings underscore the importance of air pollution control in mitigating heat-related mortality. -- Interactive effects between air pollution and elevated (equivalent) temperatures underscore the importance of air pollution control in mitigating the adverse effects of heat

Air temperature variability in a high-elevation Himalayan catchment

NARCIS (Netherlands)

Heynen, Martin; Miles, Evan; Ragettli, Silvan; Buri, Pascal; Immerzeel, Walter W.; Pellicciotti, Francesca

2016-01-01

Air temperature is a key control of processes affecting snow and glaciers in high-elevation catchments, including melt, snowfall and sublimation. It is therefore a key input variable to models of land-surface-atmosphere interaction. Despite this importance, its spatial variability is poorly

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 ...

Cellulose-Hemicellulose Interactions at Elevated Temperatures Increase Cellulose Recalcitrance to Biological Conversion

Energy Technology Data Exchange (ETDEWEB)

Mittal, Ashutosh [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Himmel, Michael E [National Renewable Energy Laboratory (NREL), Golden, CO (United States); Kumar, Rajeev [University of California, Riverside; Oak Ridge National Laboratory; ; Smith, Micholas Dean [Oak Ridge National Laboratory; University of Tennessee; Petridis, Loukas [Oak Ridge National Laboratory; University of Tennessee; Ong, Rebecca G. [Michigan Technological University; Cai, Charles M. [University of California, Riverside; Oak Ridge National Laboratory; Balan, Venkatesh [University of Houston; Dale, Bruce E. [Michigan State University; Ragauskas, Arthur J. [Oak Ridge National Laboratory; University of Tennessee; Smith, Jeremy C. [Oak Ridge National Laboratory; University of Tennessee; Wyman, Charles E. [University of California, Riverside; Oak Ridge National Laboratory

2018-01-23

It has been previously shown that cellulose-lignin droplets' strong interactions, resulting from lignin coalescence and redisposition on cellulose surface during thermochemical pretreatments, increase cellulose recalcitrance to biological conversion, especially at commercially viable low enzyme loadings. However, information on the impact of cellulose-hemicellulose interactions on cellulose recalcitrance following relevant pretreatment conditions are scarce. Here, to investigate the effects of plausible hemicellulose precipitation and re-association with cellulose on cellulose conversion, different pretreatments were applied to pure Avicel(R) PH101 cellulose alone and Avicel mixed with model hemicellulose compounds followed by enzymatic hydrolysis of resulting solids at both low and high enzyme loadings. Solids produced by pretreatment of Avicel mixed with hemicelluloses (AMH) were found to contain about 2 to 14.6% of exogenous, precipitated hemicelluloses and showed a remarkably much lower digestibility (up to 60%) than their respective controls. However, the exogenous hemicellulosic residues that associated with Avicel following high temperature pretreatments resulted in greater losses in cellulose conversion than those formed at low temperatures, suggesting that temperature plays a strong role in the strength of cellulose-hemicellulose association. Molecular dynamics simulations of hemicellulosic xylan and cellulose were found to further support this temperature effect as the xylan-cellulose interactions were found to substantially increase at elevated temperatures. Furthermore, exogenous, precipitated hemicelluloses in pretreated AMH solids resulted in a larger drop in cellulose conversion than the delignified lignocellulosic biomass containing comparably much higher natural hemicellulose amounts. Increased cellulase loadings or supplementation of cellulase with xylanases enhanced cellulose conversion for most pretreated AMH solids; however, this approach

Interactive effects of temperature and drought on cassava growth and toxicity: implications for food security?

Science.gov (United States)

Brown, Alicia L; Cavagnaro, Timothy R; Gleadow, Ros; Miller, Rebecca E

2016-10-01

Cassava is an important dietary component for over 1 billion people, and its ability to yield under drought has led to it being promoted as an important crop for food security under climate change. Despite its known photosynthetic plasticity in response to temperature, little is known about how temperature affects plant toxicity or about interactions between temperature and drought, which is important because cassava tissues contain high levels of toxic cyanogenic glucosides, a major health and food safety concern. In a controlled glasshouse experiment, plants were grown at 2 daytime temperatures (23 °C and 34 °C), and either well-watered or subject to a 1 month drought prior to harvest at 6 months. The objective was to determine the separate and interactive effects of temperature and drought on growth and toxicity. Both temperature and drought affected cassava physiology and chemistry. While temperature alone drove differences in plant height and above-ground biomass, drought and temperature × drought interactions most affected tuber yield, as well as foliar and tuber chemistry, including C : N, nitrogen and cyanide potential (CNp; total cyanide released from cyanogenic glucosides). Conditions that most stimulated growth and yield (well-watered × high temperature) effected a reduction in tuber toxicity, whereas drought inhibited growth and yield, and was associated with increased foliar and tuber toxicity. The magnitude of drought effects on tuber yield and toxicity were greater at high temperature; thus, increases in tuber CNp were not merely a consequence of reduced tuber biomass. Findings confirm that cassava is adaptable to forecast temperature increases, particularly in areas of adequate or increasing rainfall; however, in regions forecast for increased incidence of drought, the effects of drought on both food quality (tuber toxicity) and yield are a greater threat to future food security and indicate an increasing necessity for processing of

Microbial interactions with the cyanobacterium Microcystis aeruginosa and their dependence on temperature

DEFF Research Database (Denmark)

Dziallas, Claudia; Grossart, Hans-Peter

2012-01-01

and their associated community often masked this temperature effect. Both macro- and microenvironment of active cyanobacterial strains were characterized by high pH and oxygen values creating a unique habitat that potentially affects microbial diversity and function. For example, archaea including ‘anaerobic......Associated heterotrophic bacteria alter the microenvironment of cyanobacteria and potentially influence cyanobacterial development. Therefore, we studied interactions of the unicellular freshwater cyanobacterium Microcystis aeruginosa with heterotrophic bacteria. The associated bacterial community...... was greatly driven by temperature as seen by DNA Wngerprinting. However, the associated microbes also closely interacted with the cyanobacteria indicating changing ecological consequence of the associated bacterial community with temperature. Whereas concentration of dissolved organic carbon in cyanobacterial...

High temperature refrigerator

International Nuclear Information System (INIS)

Steyert, W.A. Jr.

1978-01-01

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

High-temperature superconducting phase in rare earth alloys

International Nuclear Information System (INIS)

Vedyaev, A.V.; Molodykh, O.Eh.; Savchenko, M.A.; Stefanovich, A.V.

1984-01-01

A possibility of high-temperature superconducting phase existence in rare e arth alloys with aluminium: TbAl-NdAl is predicted. Such a phase is shown t o exist at t approximately 40 k, however its existence is possible only in a nar row temperature range and it might be metastable. A possibility of a supercondu cting phase occurrence in spin glass is studied. It is shown that the first kin d phase transition to superconducting state may first occur under definite condi tions in the system. But the phase in question will be a low-temperature one be cause of rather inefficient elctron-phonon interaction. Further temperature dec rease would lead to an appearance of magnetic order and to disappearance of the superconductivity

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

High temperature strength data-base of SUS304 steel and a study on life prediction method under ceep-fatigue interaction

International Nuclear Information System (INIS)

Matsubara, Masaaki; Nitta, Akito; Ogata, Takashi; Kuwabara, Kazuo

1985-01-01

As a part of ''Study for practical use of Tank Type FBR'', ''Practical use of inelastic analysis method to FBR structural design'' is carried out as a cooperative study for three years from 1984. In this cooperative study, to establish the life prediction method under creep-fatigue interaction is one of the most important theme. To attain this purpose, many different type tests are planned and then conducted. By the way, to use these many data rapidly and effectively, it is necessary to make a data base. So in this work, we developed the simple data base of high temperature strength. And the data of SUS304 obtained at this place to this day are inputted into this data base. Next, we investigated about five life prediction methods under creep-fatigue interaction, Frequency Modified Method, Ostergren Method, Strain Range Partitioning Method, Damage Rate Approach and Strain Energy Parameter Method. As a result, Strain Range Partitioning Method can predict the lives within Factor of 2. In the other four methods, it is supported that material constants in the prediction formula are dependent on temperature. (author)

Local antiferromagnetic exchange and collaborative Fermi surface as key ingredients of high temperature superconductors

Science.gov (United States)

Hu, Jiangping; Ding, Hong

2012-01-01

Cuprates, ferropnictides and ferrochalcogenides are three classes of unconventional high temperature superconductors, who share similar phase diagrams in which superconductivity develops after a magnetic order is suppressed, suggesting a strong interplay between superconductivity and magnetism, although the exact picture of this interplay remains elusive. Here we show that there is a direct bridge connecting antiferromagnetic exchange interactions determined in the parent compounds of these materials to the superconducting gap functions observed in the corresponding superconducting materials: in all high temperature superconductors, the Fermi surface topology matches the form factor of the pairing symmetry favored by local magnetic exchange interactions. We suggest that this match offers a principle guide to search for new high temperature superconductors. PMID:22536479

High Temperature Materials Interim Data Qualification Report

International Nuclear Information System (INIS)

Lybeck, Nancy

2010-01-01

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

Brine/Rock Interaction in Deep Oceanic Layered Gabbros: Petrological Evidence from Cl-Rich Amphibole, High-Temperature Hydrothermal Veins, and Experiments

Science.gov (United States)

Currin Sala, A. M.; Koepke, J.; Almeev, R. R.; Teagle, D. A. H.; Zihlmann, B.; Wolff, P. E.

2017-12-01

Evidence of high temperature brine/rock interaction is found in hydrothermal veins and dykelets that cross-cut layered olivine gabbros in the deep palaeocrust of the Sumail Ophiolite, Sultanate of Oman. Here we present petrological and geochemical data from these samples, and an experimental attempt to simulate brine/gabbro interaction using externally heated cold seal pressure vessels. The studied natural veins and dykelets contain pargasite, hornblende, actinolite, and Cl-rich pargasite with up to 5 wt% Cl, showing a range of formation conditions from magmatic to metamorphic (hydrothermal) and thus a complex history of brine/rock interaction. In addition, the isotopic study of the radiogenic 87/86Sr and stable 18O in different amphibole types provide an estimate for the extent of seawater influence as alteration agent in the veins of the studied samples. Experiments performed at 750 °C and 200 MPa with different starting materials (chlorine-free amphibole, olivine gabbro powder) and 20 wt% NaCl aqueous brine, illustrate the process by which gabbro-hosted amphibole-rich veins evolve at subsolidus temperatures in the presence of a seawater-derived fluid. Our results demonstrate a decrease in olivine, plagioclase and magnetite content in favour of hastingsite, pargasite and magnesiohornblende, a decrease of IVAl and Ti in the starting amphibole, and an increase in Cl in amphibole, up to 0.2 Cl wt%. Our experiments show the change of magmatic pargasite towards more magnesium and silica-rich end members with results comparable to mildly chlorine-rich pargasites and hornblendes found in the natural samples studied. However, the experimental setup also presents limitations in the attainment of very high-chlorine amphibole (up to 5 wt%). Our analytical and experimental results provide further evidence for the existence of a hydrothermal cooling system in the deep oceanic crust.

High-Temperature Shape Memory Alloys

Science.gov (United States)

Biffi, C. A.; Tuissi, A.

2014-10-01

In this paper, an experimental study of laser micro-processing on a Cu-Zr-based shape memory alloy (SMA), which is suitable for high-temperature (HT) applications, is discussed. A first evaluation of the interaction between a laser beam and Zr50Cu28Ni7Co15 HT SMA is highlighted. Single laser pulses at various levels of power and pulse duration were applied to evaluate their effect on the sample surfaces. Blind and through microholes were produced with sizes on the order of a few hundreds of microns; the results were characterized from the morphological viewpoint using a scanning electron microscope. The high beam quality allows the holes to be created with good circularity and little melted material around the hole periphery. An analysis of the chemical composition was performed using energy dispersive spectroscopy, revealing that compositional changes were limited, while important oxidation occurred on the hole surfaces. Additionally, laser micro-cutting tests were also proposed to evaluate the cut edge morphology and dimensions. The main result of this paper concerned the good behavior of the material upon interaction with the laser beam, which suggests that microfeatures can be successfully produced in this alloy.

Understanding Fundamental Material Degradation Processes in High Temperature Aggressive Chemomechanical Environments

International Nuclear Information System (INIS)

2014-01-01

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

Understanding Fundamental Material Degradation Processes in High Temperature Aggressive Chemomechanical Environments

Energy Technology Data Exchange (ETDEWEB)

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

2014-01-16

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

Covalent magnetism, exchange interactions and anisotropy of the high temperature layered antiferromagnet MnB₂.

Science.gov (United States)

Khmelevskyi, S; Mohn, P

2012-01-11

The investigation of the electronic structure and magnetism for the compound MnB(2) with crystal structure type AlB(2) has been revisited to resolve contradictions between various experimental and theoretical results present in the literature. We find that MnB(2) exhibits an interesting example of a Kübler's covalent magnetism (Williams et al 1981 J. Appl. Phys. 52 2069). The covalent magnetism also appears to be the source of some disagreement between the calculated values of the magnetic moments and those given by neutron diffraction experiments. We show that this shortcoming is due to the atomic sphere approximation applied in earlier calculations. The application of the disordered local moment approach and the calculation of the inter-atomic exchange interactions within the Liechtenstein formalism reveal strong local moment antiferromagnetism with a high Néel temperature predicted from Monte Carlo simulations. A fully relativistic band structure calculation and then the application of the torque method yields a strong in-plane anisotropy of the Mn magnetic moments. The agreement of these results with neutron diffraction studies rules out any possible weak itinerant electron magnetism scenarios as proposed earlier for MnB(2).

High pressure and temperature induced structural and elastic properties of lutetium chalcogenides

Science.gov (United States)

Shriya, S.; Kinge, R.; Khenata, R.; Varshney, Dinesh

2018-04-01

The high-pressure structural phase transition and pressure as well temperature induced elastic properties of rock salt to CsCl structures in semiconducting LuX (X = S, Se, and Te) chalcogenides compound have been performed using effective interionic interaction potential with emphasis on charge transfer interactions and covalent contribution. Estimated values of phase transition pressure and the volume discontinuity in pressure-volume phase diagram indicate the structural phase transition from ZnS to NaCl structure. From the investigations of elastic constants the pressure (temperature) dependent volume collapse/expansion, melting temperature TM, Hardness (HV), and young modulus (E) the LuX lattice infers mechanical stiffening, and thermal softening.

Temperature dependence of high-resolution resonant photoemission spectra of CeSi

International Nuclear Information System (INIS)

Mimura, Kojiro; Noguchi, Satoru; Suzuki, Mitsuharu; Higashiguchi, Mitsuharu; Shimada, Kenya; Ichikawa, Kouichi; Taguchi, Yukihiro; Namatame, Hirofumi; Taniguchi, Masaki; Aita, Osamu

2005-01-01

High-resolution Ce 4d-4f resonant photoemission spectra near the Fermi level of CeSi with the Neel temperature of 5.9K have been measured at temperatures from 5.6 to 200K, in order to investigate the competition between the Ruderman-Kittel-Kasuya-Yoshida (RKKY) interaction and the Kondo effect. As temperature is decreasing down to 30K, the intensity due to the Ce 4f 5/2 1 final state increases because of the evolution of the heavy Fermion behaviour caused by the Kondo effect. The intensity, however, decreases gradually from 30 to 5.6K. This indicates that the heavy Fermion behaviour is strongly suppressed by the anti-ferromagnetic ordering due to the RKKY interaction

RNA-Seq analysis reveals insight into enhanced rice Xa7-mediated bacterial blight resistance at high temperature.

Directory of Open Access Journals (Sweden)

Stephen P Cohen

Full Text Available Plant disease is a major challenge to agriculture worldwide, and it is exacerbated by abiotic environmental factors. During some plant-pathogen interactions, heat stress allows pathogens to overcome host resistance, a phenomenon which could severely impact crop productivity considering the global warming trends associated with climate change. Despite the importance of this phenomenon, little is known about the underlying molecular mechanisms. To better understand host plant responses during simultaneous heat and pathogen stress, we conducted a transcriptomics experiment for rice plants (cultivar IRBB61 containing Xa7, a bacterial blight disease resistance (R gene, that were infected with Xanthomonas oryzae, the bacterial blight pathogen of rice, during high temperature stress. Xa7-mediated resistance is unusual relative to resistance mediated by other R genes in that it functions better at high temperatures. Using RNA-Seq technology, we identified 8,499 differentially expressed genes as temperature responsive in rice cultivar IRBB61 experiencing susceptible and resistant interactions across three time points. Notably, genes in the plant hormone abscisic acid biosynthesis and response pathways were up-regulated by high temperature in both mock-treated plants and plants experiencing a susceptible interaction and were suppressed by high temperature in plants exhibiting Xa7-mediated resistance. Genes responsive to salicylic acid, an important plant hormone for disease resistance, were down-regulated by high temperature during both the susceptible and resistant interactions, suggesting that enhanced Xa7-mediated resistance at high temperature is not dependent on salicylic acid signaling. A DNA sequence motif similar to known abscisic acid-responsive cis-regulatory elements was identified in the promoter region upstream of genes up-regulated in susceptible but down-regulated in resistant interactions. The results of our study suggest that the plant

High temperature electrical energy storage: advances, challenges, and frontiers.

Science.gov (United States)

Lin, Xinrong; Salari, Maryam; Arava, Leela Mohana Reddy; Ajayan, Pulickel M; Grinstaff, Mark W

2016-10-24

With the ongoing global effort to reduce greenhouse gas emission and dependence on oil, electrical energy storage (EES) devices such as Li-ion batteries and supercapacitors have become ubiquitous. Today, EES devices are entering the broader energy use arena and playing key roles in energy storage, transfer, and delivery within, for example, electric vehicles, large-scale grid storage, and sensors located in harsh environmental conditions, where performance at temperatures greater than 25 °C are required. The safety and high temperature durability are as critical or more so than other essential characteristics (e.g., capacity, energy and power density) for safe power output and long lifespan. Consequently, significant efforts are underway to design, fabricate, and evaluate EES devices along with characterization of device performance limitations such as thermal runaway and aging. Energy storage under extreme conditions is limited by the material properties of electrolytes, electrodes, and their synergetic interactions, and thus significant opportunities exist for chemical advancements and technological improvements. In this review, we present a comprehensive analysis of different applications associated with high temperature use (40-200 °C), recent advances in the development of reformulated or novel materials (including ionic liquids, solid polymer electrolytes, ceramics, and Si, LiFePO 4 , and LiMn 2 O 4 electrodes) with high thermal stability, and their demonstrative use in EES devices. Finally, we present a critical overview of the limitations of current high temperature systems and evaluate the future outlook of high temperature batteries with well-controlled safety, high energy/power density, and operation over a wide temperature range.

Curious Case of Positive Current Collectors: Corrosion and Passivation at High Temperature.

Science.gov (United States)

Sayed, Farheen N; Rodrigues, Marco-Tulio F; Kalaga, Kaushik; Gullapalli, Hemtej; Ajayan, P M

2017-12-20

In the evaluation of compatibility of different components of cell for high-energy and extreme-conditions applications, the highly focused are positive and negative electrodes and their interaction with electrolyte. However, for high-temperature application, the other components are also of significant influence and contribute toward the total health of battery. In present study, we have investigated the behavior of aluminum, the most common current collector for positive electrode materials for its electrochemical and temperature stability. For electrochemical stability, different electrolytes, organic and room temperature ionic liquids with varying Li salts (LiTFSI, LiFSI), are investigated. The combination of electrochemical and spectroscopic investigations reflects the varying mechanism of passivation at room and high temperature, as different compositions of decomposed complexes are found at the surface of metals.

ASSET, An Information System for Alloy Corrosion in High Temperature Gases

International Nuclear Information System (INIS)

R. C. John; A. D. Pelton; A. L. Young; W. T. Thompson; I. G. Wright

2001-01-01

A large database for corrosion data and a corrosion prediction information system for metals and alloys corroding in high-temperature gases have been created. Corrosion data for about 75 commercial alloys, 4600 corrosion data measurements, and six million exposure hours have been compiled into an information system, ASSET. ASSET allows prediction of sound metal thickness losses for metals and alloys corroding by several common corrosion mechanisms at high-temperatures as functions of gas composition, temperature, time, and alloy. This paper presents examples of predicted metal losses of alloys corroding in standard conditions for several corrosion mechanisms expected in high-temperature gases. ASSET also provides a comprehensive capability to analyze the thermochemical interactions between alloys, corrosion products and exposure conditions. Some of the uses of the data compilation and the corrosion prediction feature are illustrated for oxidizing, sulfidizing, sulfidizing/oxidizing , and carburizing conditions

Correlation Decay in Fermionic Lattice Systems with Power-Law Interactions at Nonzero Temperature

Science.gov (United States)

Hernández-Santana, Senaida; Gogolin, Christian; Cirac, J. Ignacio; Acín, Antonio

2017-09-01

We study correlations in fermionic lattice systems with long-range interactions in thermal equilibrium. We prove a bound on the correlation decay between anticommuting operators and generalize a long-range Lieb-Robinson-type bound. Our results show that in these systems of spatial dimension D with, not necessarily translation invariant, two-site interactions decaying algebraically with the distance with an exponent α ≥2 D , correlations between such operators decay at least algebraically to 0 with an exponent arbitrarily close to α at any nonzero temperature. Our bound is asymptotically tight, which we demonstrate by a high temperature expansion and by numerically analyzing density-density correlations in the one-dimensional quadratic (free, exactly solvable) Kitaev chain with long-range pairing.

High temperature measurements in severe accident experiments on the PLINIUS Platform

International Nuclear Information System (INIS)

Bouyer, V.; Cassiaut-Louis, N.; Fouquart, P.; Journeau, C.; Piluso, P.; Parga, C.

2013-06-01

Severe accident experiments are conducted on the PLINIUS platform in Cadarache, using prototypic corium. During these experiments, it is essential to measure the temperature to know the thermo-physical state of the corium in static and dynamic conditions or to monitor the concrete ablation phenomenology. Temperature in the corium can reach about 2000 to 3000 K. Such aggressive conditions restrict the type of diagnostics that can be employed to do high temperature measurements during the experiments. We employ both non-intrusive (pyrometers) and intrusive (K-type and C-type thermocouples) diagnostics. In this paper, we present the different high temperature measurements techniques and the results that can be obtained in severe accident experiments as corium heating tests and molten core concrete interaction experiments. (authors)

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

Interacting temperature and water activity modulate production of ...

African Journals Online (AJOL)

West African Journal of Applied Ecology ... Concentrations of DA were further modulated by interactions of temperature and aw. ... was at 0.98 aw and 35°C while the lowest was at 0.96 aw and 35°C. The abiotic interactions that supported biomass production appeared different from what was required for production of DA.

Research Activities on Development of Piping Design Methodology of High Temperature Reactors

Energy Technology Data Exchange (ETDEWEB)

Huh, Nam-Su [Seoul National Univ. of Science and Technology, Seoul(Korea, Republic of); Won, Min-Gu [Sungkyukwan Univ., Suwon (Korea, Republic of); Oh, Young-Jin [KEPCO Engineering and Construction Co. Inc., Gimcheon (Korea, Republic of); Lee, Hyeog-Yeon; Kim, Yoo-Gon [Korea Atomic Energy Research Institute, Daejeon(Korea, Republic of)

2016-10-15

A SFR is operated at high temperature and low pressure compared with commercial pressurized water reactor (PWR), and such an operating condition leads to time-dependent damages such as creep rupture, excessive creep deformation, creep-fatigue interaction and creep crack growth. Thus, high temperature design and structural integrity assessment methodology should be developed considering such failure mechanisms. In terms of design of mechanical components of SFR, ASME B and PV Code, Sec. III, Div. 5 and RCC-MRx provide high temperature design and assessment procedures for nuclear structural components operated at high temperature, and a Leak-Before-Break (LBB) assessment procedure for high temperature piping is also provided in RCC-MRx, A16. Three web-based evaluation programs based on the current high temperature codes were developed for structural components of high temperature reactors. Moreover, for the detailed LBB analyses of high temperature piping, new engineering methods for predicting creep C*-integral and creep COD rate based either on GE/EPRI or on reference stress concepts were proposed. Finally, the numerical methods based on Garofalo's model and RCC-MRx have been developed, and they have been implemented into ABAQUS. The predictions based on both models were compared with the experimental results, and it has been revealed that the predictions from Garafalo's model gave somewhat successful results to describe the deformation behavior of Gr. 91 at elevated temperatures.

Multiple stressors in agricultural streams: a mesocosm study of interactions among raised water temperature, sediment addition and nutrient enrichment.

Directory of Open Access Journals (Sweden)

Jeremy J Piggott

Full Text Available Changes to land use affect streams through nutrient enrichment, increased inputs of sediment and, where riparian vegetation has been removed, raised water temperature. We manipulated all three stressors in experimental streamside channels for 30 days and determined the individual and pair-wise combined effects on benthic invertebrate and algal communities and on leaf decay, a measure of ecosystem functioning. We added nutrients (phosphorus+nitrogen; high, intermediate, natural and/or sediment (grain size 0.2 mm; high, intermediate, natural to 18 channels supplied with water from a nearby stream. Temperature was increased by 1.4°C in half the channels, simulating the loss of upstream and adjacent riparian shade. Sediment affected 93% of all biological response variables (either as an individual effect or via an interaction with another stressor generally in a negative manner, while nutrient enrichment affected 59% (mostly positive and raised temperature 59% (mostly positive. More of the algal components of the community responded to stressors acting individually than did invertebrate components, whereas pair-wise stressor interactions were more common in the invertebrate community. Stressors interacted often and in a complex manner, with interactions between sediment and temperature most common. Thus, the negative impact of high sediment on taxon richness of both algae and invertebrates was stronger at raised temperature, further reducing biodiversity. In addition, the decay rate of leaf material (strength loss accelerated with nutrient enrichment at ambient but not at raised temperature. A key implication of our findings for resource managers is that the removal of riparian shading from streams already subjected to high sediment inputs, or land-use changes that increase erosion or nutrient runoff in a landscape without riparian buffers, may have unexpected effects on stream health. We highlight the likely importance of intact or restored buffer

Interaction of titanium beryllide with steam at high temperatures

International Nuclear Information System (INIS)

Munakata, Kenzo; Wada, Kohei; Akimoto, Yusuke; Takeda, Haruki; Nakamura, Ayano; Kim, Jae-Hwan; Nakamichi, Masaru

2014-01-01

Highlights: • Some central and peripheral parts of a plasma sintered titanium beryllide disk were exposed to water vapor at 1273 K. • H 2 gas generation rate of the central part was found to be lower than that of the peripheral part. • Central parts of a plasma sintered titanium beryllide disk were exposed to water vapor at 1273 K with different temperature controls. • H 2 gas generation was found to be affected by thermal treatment. - Abstract: Some central and peripheral parts of a plasma sintered titanium beryllide disk were exposed to water vapor at temperatures raised up to 1273 K. Hydrogen generation and oxidation properties of the titanium beryllide were investigated. The amount of H 2 generation of the central part was found to be smaller than that of the peripheral part, and this can be attributed to difference in the larger fractions of the Be phase on their surface. Thus, different temperature programed experiments were performed using samples cut out from the central part. In an experiment, the temperature of the sample was raised stepwise and behavior of hydrogen generation was investigated. It was found that hydrogen generation does not take place at the temperatures below 1273 K and the amount of hydrogen generated is far smaller. Another experiment was carried out after a sample had been annealed under a dry Ar gas at 1273 K. In this case, the amount of hydrogen generated from the surface decreased. These results indicate the thermal treatment of the titanium beryllide samples affects their reactivity with water vapor

High-temperature superconductivity

International Nuclear Information System (INIS)

Lynn, J.W.

1990-01-01

This book discusses development in oxide materials with high superconducting transition temperature. Systems with Tc well above liquid nitrogen temperature are already a reality and higher Tc's are anticipated. The author discusses how the idea of a room-temperature superconductor appears to be a distinctly possible outcome of materials research

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

Science.gov (United States)

Morinari, Takao

2018-06-01

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

Application of laser resonance scattering to the study of high-temperature plasma-wall interaction

International Nuclear Information System (INIS)

Maeda, Mitsuo; Muraoka, Katsunori; Hamamoto, Makoto; Akazaki, Masanori; Miyazoe, Yasushi

1981-01-01

Studies on laser resonance scattering and its application to the study of high-temperature plasma-wall interaction are reviewed. The application of dye laser beam to resonant scattering method has been developed. This method is able to detect low density atoms. The fluorescent photon counts can be estimated for a two-level system and a three-level system. The S/N ratio, Which is in close connection with the detection limit, has been estimated. The doppler effect due to the thermal motion of atoms is taken into consideration. The calibration of the absolute number of atoms is necessary. Tunable coherent light is used as the light source for resonance scattering method. This is able to excite atoms strongly and to increase the detection efficiency. As dye lasers, a N 2 laser, a YAG laser, and a KrF excimer laser have been studied. In VUV region, rare gas or rare gas halide lasers can be used. The strong output power can be expected when the resonance lines of atoms meet the synchronizing region of the excimer laser. The resonance scattering method is applied to the detection of impurity metal atoms in plasma. The studies of laser systems for the detection of hydrogen atoms are also in progress. (Kato, T.)

Potassium and soot interaction in fast biomass pyrolysis at high temperatures

DEFF Research Database (Denmark)

Trubetskaya, Anna; Hofmann Larsen, Flemming; Shchukarev, Andrey

2018-01-01

2 reactivity was studied by thermogravimetric analysis. The XPS results showed that potassium incorporation with oxygen-containing surface groups in the soot matrix did not occur during high temperature pyrolysis. The potassium was mostly found as water-soluble salts such as KCl, KOH, KHCO3 and K2CO...... potassium amount was incorporated in the soot matrix during pyrolysis. Raman spectroscopy results showed that the carbon chemistry of biomass soot also affected the CO2 reactivity. The less reactive pinewood soot was more graphitic than herbaceous biomass soot samples with the disordered carbon structure...

Comparison of signaling interactions determining annual and perennial plant growth in response to low temperature

Directory of Open Access Journals (Sweden)

Astrid eWingler

2015-01-01

Full Text Available Low temperature inhibits plant growth despite the fact that considerable rates of photosynthetic activity can be maintained. Instead of lower rates of photosynthesis, active inhibition of cell division and expansion is primarily responsible for reduced growth. This results in sink limitation and enables plants to accumulate carbohydrates that act as compatible solutes or are stored throughout the winter to enable re-growth in spring. Regulation of growth in response to temperature therefore requires coordination with carbon metabolism, e.g. via the signaling metabolite trehalose-6-phosphate. The phytohormones gibberellins (GA and jasmonate (JA play an important role in regulating growth in response to temperature. Growth restriction at low temperature is mainly mediated by DELLA proteins, whose degradation is promoted by GA. For annual plants, it has been shown that the GA/DELLA pathway interacts with JA signaling and C-repeat binding factor (CBF dependent cold acclimation, but these interactions have not been explored in detail for perennials. Growth regulation in response to seasonal factors is, however, particularly important in perennials, especially at high latitudes. In autumn, growth cessation in trees is caused by shortening of the daylength in interaction with phytohormone signaling. In perennial grasses seasonal differences in the sensitivity to GA may enable enhanced growth in spring. This review provides an overview of the signaling interactions that determine plant growth at low temperature and highlights gaps in our knowledge, especially concerning the seasonality of signaling responses in perennial plants.

Self-consistent treatment of interacting spin waves at finite temperatures; Etude a temperature finie d'un systeme d'ondes de spin en interaction dans une approximation self-consistante

Energy Technology Data Exchange (ETDEWEB)

Bloch, M [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

1965-06-01

A spin wave theory is developed where account is taken of spin wave interactions at finite temperatures. The temperature dependence of the spin wave energies and of the magnetization is derived. The theory is developed for ferro-, ferri-, and antiferromagnets. (author) [French] On expose une theorie d'ondes de spin en interaction a temperature finie. On en deduit l'evolution avec la temperature du spectre en energie des ondes de spin et de l'aimantation. La theorie est developpee pour les corps ferro-, ferri-, et antiferromagnetiques. (auteur)

Modelling of the interactions between B4C and stainless steel at high temperatures

International Nuclear Information System (INIS)

Veshchunov, M.S.

1995-01-01

Results of detailed chemical-analytical examinations of B 4 C/stainless steel (s.s.) reaction couples obtained at temperatures of 1000, 1100 and 1200 C, and a theoretical model developed on the basis of these results, which describes the reaction layers growth kinetics, are presented. The examinations were carried out by AES and XMA methods to measure concentration profiles of different elements in the various phases and the thicknesses of the formed reaction layers as function of time to determine the growth kinetics. A new approach for modelling of diffusion mass transfer through a two-phase zone in multicomponent systems is further developed for the description of the growth kinetics of the reaction layer consisting of Me 2 B (Me≡Fe, Cr, Ni) precipitates in the stainless steel matrix. Diffusion coefficients of Cr in all phases of the reaction zone are calculated. These data together with the measured boundary concentrations of the elements allow the complete description of the B 4 C/s.s. interaction kinetics at the examined test temperatures by the proposed model. (orig.)

FEM Modeling of the Relationship between the High-Temperature Hardness and High-Temperature, Quasi-Static Compression Experiment.

Science.gov (United States)

Zhang, Tao; Jiang, Feng; Yan, Lan; Xu, Xipeng

2017-12-26

The high-temperature hardness test has a wide range of applications, but lacks test standards. The purpose of this study is to develop a finite element method (FEM) model of the relationship between the high-temperature hardness and high-temperature, quasi-static compression experiment, which is a mature test technology with test standards. A high-temperature, quasi-static compression test and a high-temperature hardness test were carried out. The relationship between the high-temperature, quasi-static compression test results and the high-temperature hardness test results was built by the development of a high-temperature indentation finite element (FE) simulation. The simulated and experimental results of high-temperature hardness have been compared, verifying the accuracy of the high-temperature indentation FE simulation.The simulated results show that the high temperature hardness basically does not change with the change of load when the pile-up of material during indentation is ignored. The simulated and experimental results show that the decrease in hardness and thermal softening are consistent. The strain and stress of indentation were analyzed from the simulated contour. It was found that the strain increases with the increase of the test temperature, and the stress decreases with the increase of the test temperature.

FEM Modeling of the Relationship between the High-Temperature Hardness and High-Temperature, Quasi-Static Compression Experiment

Directory of Open Access Journals (Sweden)

Tao Zhang

2017-12-01

Full Text Available The high-temperature hardness test has a wide range of applications, but lacks test standards. The purpose of this study is to develop a finite element method (FEM model of the relationship between the high-temperature hardness and high-temperature, quasi-static compression experiment, which is a mature test technology with test standards. A high-temperature, quasi-static compression test and a high-temperature hardness test were carried out. The relationship between the high-temperature, quasi-static compression test results and the high-temperature hardness test results was built by the development of a high-temperature indentation finite element (FE simulation. The simulated and experimental results of high-temperature hardness have been compared, verifying the accuracy of the high-temperature indentation FE simulation.The simulated results show that the high temperature hardness basically does not change with the change of load when the pile-up of material during indentation is ignored. The simulated and experimental results show that the decrease in hardness and thermal softening are consistent. The strain and stress of indentation were analyzed from the simulated contour. It was found that the strain increases with the increase of the test temperature, and the stress decreases with the increase of the test temperature.

Complex and interactive effects of ocean acidification and temperature on epilithic and endolithic coral-reef turf algal assemblages

Science.gov (United States)

Johnson, Maggie D.; Comeau, Steeve; Lantz, Coulson A.; Smith, Jennifer E.

2017-12-01

Turf algal assemblages are ubiquitous primary producers on coral reefs, but little is known about the response of this diverse group to ocean acidification (OA) across different temperatures. We tested the hypothesis that CO2 influences the functional response of epilithic and endolithic turf assemblages to increasing temperature. Replicate carbonate plugs covered by turf were collected from the reef and exposed to ambient and high pCO2 (1000 µatm) conditions for 3 weeks. Each pCO2 treatment was replicated across six temperatures (24.0-31.5 °C) that spanned the full seasonal temperature range on a fringing reef in Moorea, French Polynesia, and included one warming treatment (3 °C above daily average temperatures). Temperature and CO2 enrichment had complex, and sometimes interactive, effects on turf metabolism and growth. Photosynthetic and respiration rates were enhanced by increasing temperature, with an interactive effect of CO2 enrichment. Photosynthetic rates were amplified by high CO2 in the warmest temperatures, while the increase in respiration rates with temperature were enhanced under ambient CO2. Epilithic turf growth rates were not affected by temperature, but increased in response to CO2 enrichment. We found that CO2 and temperature interactively affected the endolithic assemblage, with the highest growth rates under CO2 enrichment, but only at the warmest temperatures. These results demonstrate how OA may influence algal physiology and growth across a range of ecologically relevant temperatures, and indicate that the effects of CO2 enrichment on coral-reef turf assemblages can be temperature dependent. The complex effects of CO2 enrichment and temperature across a suite of algal responses illustrates the importance of incorporating multiple stressors into global change experiments.

Temperature-Dependent Species Interactions Shape Priority Effects and the Persistence of Unequal Competitors.

Science.gov (United States)

Grainger, Tess Nahanni; Rego, Adam Ivan; Gilbert, Benjamin

2018-02-01

The order of species arrival at a site can determine the outcome of competitive interactions when early arrivers alter the environment or deplete shared resources. These priority effects are predicted to be stronger at high temperatures, as higher vital rates caused by warming allow early arrivers to more rapidly impact a shared environment. We tested this prediction using a pair of congeneric aphid species that specialize on milkweed plants. We manipulated temperature and arrival order of the two aphid species and measured aphid population dynamics and milkweed survival and defensive traits. We found that warming increased the impact of aphids on the quantity and quality of milkweed, which amplified the importance of priority effects by increasing the competitive exclusion of the inferior competitor when it arrived late. Warming also enhanced interspecific differences in dispersal, which could alter relative arrival times at a regional scale. Our experiment provides a first link between temperature-dependent trophic interactions, priority effects, and dispersal. This study suggests that the indirect and cascading effects of temperature observed here may be important determinants of diversity in the temporally and spatially complex landscapes that characterize ecological communities.

Supersymmetry at high temperatures

International Nuclear Information System (INIS)

Das, A.; Kaku, M.

1978-01-01

We investigate the properties of Green's functions in a spontaneously broken supersymmetric model at high temperatures. We show that, even at high temperatures, we do not get restoration of supersymmetry, at least in the one-loop approximation

High temperature high vacuum creep testing facilities

International Nuclear Information System (INIS)

Matta, M.K.

1985-01-01

Creep is the term used to describe time-dependent plastic flow of metals under conditions of constant load or stress at constant high temperature. Creep has an important considerations for materials operating under stresses at high temperatures for long time such as cladding materials, pressure vessels, steam turbines, boilers,...etc. These two creep machines measures the creep of materials and alloys at high temperature under high vacuum at constant stress. By the two chart recorders attached to the system one could register time and temperature versus strain during the test . This report consists of three chapters, chapter I is the introduction, chapter II is the technical description of the creep machines while chapter III discuss some experimental data on the creep behaviour. Of helium implanted stainless steel. 13 fig., 3 tab

Simulations of dimensionally reduced effective theories of high temperature QCD

CERN Document Server

Hietanen, Ari

Quantum chromodynamics (QCD) is the theory describing interaction between quarks and gluons. At low temperatures, quarks are confined forming hadrons, e.g. protons and neutrons. However, at extremely high temperatures the hadrons break apart and the matter transforms into plasma of individual quarks and gluons. In this theses the quark gluon plasma (QGP) phase of QCD is studied using lattice techniques in the framework of dimensionally reduced effective theories EQCD and MQCD. Two quantities are in particular interest: the pressure (or grand potential) and the quark number susceptibility. At high temperatures the pressure admits a generalised coupling constant expansion, where some coefficients are non-perturbative. We determine the first such contribution of order g^6 by performing lattice simulations in MQCD. This requires high precision lattice calculations, which we perform with different number of colors N_c to obtain N_c-dependence on the coefficient. The quark number susceptibility is studied by perf...

Ultra-high temperature direct propulsion

International Nuclear Information System (INIS)

Araj, K.J.; Slovik, G.; Powell, J.R.; Ludewig, H.

1987-01-01

Potential advantages of ultra-high exhaust temperature (3000 K - 4000 K) direct propulsion nuclear rockets are explored. Modifications to the Particle Bed Reactor (PBR) to achieve these temperatures are described. Benefits of ultra-high temperature propulsion are discussed for two missions - orbit transfer (ΔV = 5546 m/s) and interplanetary exploration (ΔV = 20000 m/s). For such missions ultra-high temperatures appear to be worth the additional complexity. Thrust levels are reduced substantially for a given power level, due to the higher enthalpy caused by partial disassociation of the hydrogen propellant. Though technically challenging, it appears potentially feasible to achieve such ultra high temperatures using the PBR

Ambient-temperature high damping capacity in TiPd-based martensitic alloys

Energy Technology Data Exchange (ETDEWEB)

Xue, Dezhen [Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Zhou, Yumei, E-mail: zhouyumei@mail.xjtu.edu.cn [Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Ding, Xiangdong [Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Otsuka, Kazuhiro [Ferroic Physics Group, National Institute for Materials Science, Tsukuba 305-0047, Ibaraki (Japan); Lookman, Turab [Theoretical Division, Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Sun, Jun [Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Ren, Xiaobing [Multi-disciplinary Materials Research Center, Frontier Institute of Science and Technology, State Key Laboratory for Mechanical Behavior of Materials, Xi' an Jiaotong University, Xi' an 710049 (China); Ferroic Physics Group, National Institute for Materials Science, Tsukuba 305-0047, Ibaraki (Japan)

2015-04-24

Shape memory alloys (SMAs) have attracted considerable attention for their high damping capacities. Here we investigate the damping behavior of Ti{sub 50}(Pd{sub 50−x}D{sub x}) SMAs (D=Fe, Co, Mn, V) by dynamic mechanical analysis. We find that these alloys show remarkably similar damping behavior. There exists a sharp damping peak associated with the B2–B19 martensitic transformation and a high damping plateau (Q{sup −1}~0.02–0.05) over a wide ambient-temperature range (220–420 K) due to the hysteretic twin boundary motion. After doping hydrogen into the above alloys, a new relaxation-type damping peak appears in the martensite phase over 270–360 K. Such a peak is considered to originate from the interaction of hydrogen atoms with twin boundaries and the corresponding damping capacity (Q{sup −1}~0.05–0.09) is enhanced by roughly twice that of the damping plateau for each alloy. Moreover, the relaxation peaks are at higher temperatures for the TiPd-based alloys (270–370 K) than for the TiNi-based alloys (190–260 K). We discuss the influence of hydrogen diffusion, mobility of twin boundaries and hydrogen–twin boundary interaction on the temperature range of the relaxation peak. Our results suggest that a martensite, with appropriate values for twinning shear and hydrogen doping level, provides a route towards developing high damping SMAs for applications in desired temperature ranges.

Ambient-temperature high damping capacity in TiPd-based martensitic alloys

International Nuclear Information System (INIS)

Xue, Dezhen; Zhou, Yumei; Ding, Xiangdong; Otsuka, Kazuhiro; Lookman, Turab; Sun, Jun; Ren, Xiaobing

2015-01-01

Shape memory alloys (SMAs) have attracted considerable attention for their high damping capacities. Here we investigate the damping behavior of Ti 50 (Pd 50−x D x ) SMAs (D=Fe, Co, Mn, V) by dynamic mechanical analysis. We find that these alloys show remarkably similar damping behavior. There exists a sharp damping peak associated with the B2–B19 martensitic transformation and a high damping plateau (Q −1 ~0.02–0.05) over a wide ambient-temperature range (220–420 K) due to the hysteretic twin boundary motion. After doping hydrogen into the above alloys, a new relaxation-type damping peak appears in the martensite phase over 270–360 K. Such a peak is considered to originate from the interaction of hydrogen atoms with twin boundaries and the corresponding damping capacity (Q −1 ~0.05–0.09) is enhanced by roughly twice that of the damping plateau for each alloy. Moreover, the relaxation peaks are at higher temperatures for the TiPd-based alloys (270–370 K) than for the TiNi-based alloys (190–260 K). We discuss the influence of hydrogen diffusion, mobility of twin boundaries and hydrogen–twin boundary interaction on the temperature range of the relaxation peak. Our results suggest that a martensite, with appropriate values for twinning shear and hydrogen doping level, provides a route towards developing high damping SMAs for applications in desired temperature ranges

Extreme implanting in Si: A study of ion-induced damage at high temperature and high dose

International Nuclear Information System (INIS)

Holland, O.W.

1994-01-01

Ion-solid interactions near room temperature and below have been well studied in single-crystal Si. While this has led to a better understanding of the mechanisms responsible for nucleation and growth of lattice damage during irradiation, these studies have not, in general, been extended to high temperatures (e.g., >200 degrees C). This is the case despite the commercialization of ion beam technologies which utilize high-temperature processing, such as separation by implantation of oxygen (SIMOX). In this process, a silicon-on-insulator (SOI) material is produced by implanting a high dose of oxygen ions into a Si wafer to form a buried, stoichiometric oxide layer. Results will be presented of a study of damage accumulation during high-dose implantation of Si at elevated temperatures. In particular, O + -ions were used because of the potential impact of the results on the SIMOX technology. It will be shown that the nature of the damage accumulation at elevated temperatures is quite distinctive and portends the presence of a new mechanism, one which is only dominant under the extreme conditions encountered during ion beam synthesis (i.e., high temperature and high dose). This mechanism is discussed and shown to be quite general and not dependent on the chemical identity of the ions. Also, techniques for suppressing this mechanism by open-quotes defect engineeringclose quotes are discussed. Such techniques are technologically relevant because they offer the possibility of reducing the defect density of the SOI produced by SIMOX

Temperature-dependent optical potential and mean free path based on Skyrme interactions

International Nuclear Information System (INIS)

Ge Lingxiao; Zhuo Yizhong; Noerenberg, W.; Technische Hochschule Darmstadt

1986-03-01

Optical potentials and mean free paths of nucleons at finite temperatures are studied by utilizing effective Skyrme interactions which yield 'good' optical potentials at zero temperature. The results for nuclear matter (symmetric and asymmetric) are applied within the local density approximation of finite nuclei at various temperatures. Because of the limitation due to zero-range forces used and the assumptions of temperature independent nuclear densities and effective Skyrme interactions made, the calculations are expected to be limited to nucleon energies between 10 and 50 MeV above the Fermi energy and to nuclear temperatures of less than 8 MeV. (orig.)

Interactive effects of temperature and habitat complexity on freshwater communities.

Science.gov (United States)

Scrine, Jennifer; Jochum, Malte; Ólafsson, Jón S; O'Gorman, Eoin J

2017-11-01

Warming can lead to increased growth of plants or algae at the base of the food web, which may increase the overall complexity of habitat available for other organisms. Temperature and habitat complexity have both been shown to alter the structure and functioning of communities, but they may also have interactive effects, for example, if the shade provided by additional habitat negates the positive effect of temperature on understory plant or algal growth. This study explored the interactive effects of these two major environmental factors in a manipulative field experiment, by assessing changes in ecosystem functioning (primary production and decomposition) and community structure in the presence and absence of artificial plants along a natural stream temperature gradient of 5-18°C. There was no effect of temperature or habitat complexity on benthic primary production, but epiphytic production increased with temperature in the more complex habitat. Cellulose decomposition rate increased with temperature, but was unaffected by habitat complexity. Macroinvertebrate communities were less similar to each other as temperature increased, while habitat complexity only altered community composition in the coldest streams. There was also an overall increase in macroinvertebrate abundance, body mass, and biomass in the warmest streams, driven by increasing dominance of snails and blackfly larvae. Presence of habitat complexity, however, dampened the strength of this temperature effect on the abundance of macroinvertebrates in the benthos. The interactive effects that were observed suggest that habitat complexity can modify the effects of temperature on important ecosystem functions and community structure, which may alter energy flow through the food web. Given that warming is likely to increase habitat complexity, particularly at higher latitudes, more studies should investigate these two major environmental factors in combination to improve our ability to predict the

High temperature structural silicides

International Nuclear Information System (INIS)

Petrovic, J.J.

1997-01-01

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

High temperature resistive phase transition in A15 high temperature superconductors

International Nuclear Information System (INIS)

Chu, C.W.; Huang, C.Y.; Schmidt, P.H.; Sugawara, K.

1976-01-01

Resistive measurements were made on A15 high temperature superconductors. Anomalies indicative of a phase transition were observed at 433 0 K in a single crystal Nb 3 Sn and at 485 0 K in an unbacked Nb 3 Ge sputtered thin film. Results are compared with the high temperature transmission electron diffraction studies of Nb 3 Ge films by Schmidt et al. A possible instability in the electron energy spectrum is discussed

Hydration of Rhyolitic Glasses: Comparison Between High- and Low-Temperature Processes

Science.gov (United States)

Anovitz, L.; Fayek, M.; Cole, D. R.; Carter, T.

2012-12-01

While a great deal is known about the interaction between water and rhyolitic glasses and melts at temperatures above the glass transition, the nature of this interaction at lower temperatures is more obscure. Comparisons between high- and low-temperature diffusive studies suggest that several factors play an important role under lower-temperatures conditions that are not significant at higher temperatures. Surface concentrations, which equilibrate quickly at high temperature, change far more slowly as temperatures decrease, and may not equilibrate at room temperature for hundreds or thousands of years. Coupled with temperature-dependent diffusion coefficients this complicates calculation of diffusion profiles as a function of time. A key factor in this process appears to be the inability of "self-stress", caused by the in-diffusing species, to relax at lower temperatures, a result expected below the glass transition. Regions of the glass hydrated at low temperatures are strongly optically anisotropic, and preliminary calculations suggest that the magnitude of stress involved may be very high. On the microstuctural scale, extrapolations of high-temperature FTIR data to lower temperatures suggests there should be little or no hydroxyl present in glasses "hydrated" at low temperatures. Analyses of both block and powder samples suggest that this is generally true in the bulk of the hydrated glass, excluding hydroxyl groups that formed during the initial cooling of the melt. However, hydroxyl do groups appear to be present at the glass surface, where both SIMS and neutron reflectometry data suggest hydration levels may be higher than projected from the bulk of the glass. Isotopic exchange experiments also suggest that bonding is relatively weak, as hydration water exchanges readily with the enviroment. All of these observations lead to the conclusion that the observed stress is due to the presence of interstructural, rather than bonded, water. This likely explains the

Metabolome Integrated Analysis of High-Temperature Response in Pinus radiata

Directory of Open Access Journals (Sweden)

Mónica Escandón

2018-04-01

Full Text Available The integrative omics approach is crucial to identify the molecular mechanisms underlying high-temperature response in non-model species. Based on future scenarios of heat increase, Pinus radiata plants were exposed to a temperature of 40°C for a period of 5 days, including recovered plants (30 days after last exposure to 40°C in the analysis. The analysis of the metabolome using complementary mass spectrometry techniques (GC-MS and LC-Orbitrap-MS allowed the reliable quantification of 2,287 metabolites. The analysis of identified metabolites and highlighter metabolic pathways across heat time exposure reveal the dynamism of the metabolome in relation to high-temperature response in P. radiata, identifying the existence of a turning point (on day 3 at which P. radiata plants changed from an initial stress response program (shorter-term response to an acclimation one (longer-term response. Furthermore, the integration of metabolome and physiological measurements, which cover from the photosynthetic state to hormonal profile, suggests a complex metabolic pathway interaction network related to heat-stress response. Cytokinins (CKs, fatty acid metabolism and flavonoid and terpenoid biosynthesis were revealed as the most important pathways involved in heat-stress response in P. radiata, with zeatin riboside (ZR and isopentenyl adenosine (iPA as the key hormones coordinating these multiple and complex interactions. On the other hand, the integrative approach allowed elucidation of crucial metabolic mechanisms involved in heat response in P. radiata, as well as the identification of thermotolerance metabolic biomarkers (L-phenylalanine, hexadecanoic acid, and dihydromyricetin, crucial metabolites which can reschedule the metabolic strategy to adapt to high temperature.

The synergy of corrosion and fretting wear process on Inconel 690 in the high temperature high pressure water environment

Science.gov (United States)

Wang, Zihao; Xu, Jian; Li, Jie; Xin, Long; Lu, Yonghao; Shoji, Tetsuo; Takeda, Yoichi; Otsuka, Yuichi; Mutoh, Yoshiharu

2018-04-01

The synergistic effect of corrosion and fretting process of the steam generator (SG) tube was investigated by using a self-designed high temperature test rig in this paper. The experiments were performed at 100°C , 200°C and 288°C , respectively. The fretting corrosion damage was studied by optical microscopy (OM), scanning electron microscope (SEM), energy dispersive spectrometer (EDS), Raman spectroscopy and auger electron spectroscopy (AES). The results demonstrated that the corrosion process in high temperature high pressure (HTHP) water environment had a distinct interaction with the fretting process of Inconel 690. With the increment of temperature, the damage mechanism changed from a simple mechanical process to a mechanochemical process.

Theory of laser-induced demagnetization at high temperatures

KAUST Repository

Manchon, Aurelien

2012-02-17

Laser-induced demagnetization is theoretically studied by explicitly taking into account interactions among electrons, spins, and lattice. Assuming that the demagnetization processes take place during the thermalization of the subsystems, the temperature dynamics is given by the energy transfer between the thermalized interacting baths. These energy transfers are accounted for explicitly through electron-magnon and electron-phonon interactions, which govern the demagnetization time scale. By properly treating the spin system in a self-consistent random phase approximation, we derive magnetization dynamic equations for a broad range of temperature. The dependence of demagnetization on the temperature and pumping laser intensity is calculated in detail. In particular, we show several salient features for understanding magnetization dynamics near the Curie temperature. While the critical slowdown in dynamics occurs, we find that an external magnetic field can restore the fast dynamics. We discuss the implication of the fast dynamics in the application of heat-assisted magnetic recording.

Theory of laser-induced demagnetization at high temperatures

KAUST Repository

Manchon, Aurelien; Li, Q.; Xu, L.; Zhang, S.

2012-01-01

Laser-induced demagnetization is theoretically studied by explicitly taking into account interactions among electrons, spins, and lattice. Assuming that the demagnetization processes take place during the thermalization of the subsystems, the temperature dynamics is given by the energy transfer between the thermalized interacting baths. These energy transfers are accounted for explicitly through electron-magnon and electron-phonon interactions, which govern the demagnetization time scale. By properly treating the spin system in a self-consistent random phase approximation, we derive magnetization dynamic equations for a broad range of temperature. The dependence of demagnetization on the temperature and pumping laser intensity is calculated in detail. In particular, we show several salient features for understanding magnetization dynamics near the Curie temperature. While the critical slowdown in dynamics occurs, we find that an external magnetic field can restore the fast dynamics. We discuss the implication of the fast dynamics in the application of heat-assisted magnetic recording.

High-entropy alloys as high-temperature thermoelectric materials

Energy Technology Data Exchange (ETDEWEB)

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

2015-11-14

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

Combined Non-Target Effects of Insecticide and High Temperature on the Parasitoid Bracon nigricans.

Directory of Open Access Journals (Sweden)

Khaled Abbes

Full Text Available We studied the acute toxicity and the sublethal effects, on reproduction and host-killing activity, of four widely used insecticides on the generalist parasitoid Bracon nigricans (Hymenoptera: Braconidae, a natural enemy of the invasive tomato pest, Tuta absoluta (Lepidoptera: Gelechiidae. Laboratory bioassays were conducted applying maximum insecticide label rates at three constant temperatures, 25, 35 and 40°C, considered as regular, high and very high, respectively. Data on female survival and offspring production were used to calculate population growth indexes as a measure of population recovery after pesticide exposure. Spinetoram caused 80% mortality at 25°C and 100% at higher temperatures, while spinosad caused 100% mortality under all temperature regimes. Cyantraniliprole was slightly toxic to B. nigricans adults in terms of acute toxicity at the three temperatures, while it did not cause any sublethal effects in egg-laying and host-killing activities. The interaction between the two tested factors (insecticide and temperature significantly influenced the number of eggs laid by the parasitoid, which was the lowest in the case of females exposed to chlorantraniliprole at 35°C. Furthermore, significantly lower B. nigricans demographic growth indexes were estimated for all the insecticides under all temperature conditions, with the exception of chlorantraniliprole at 25°C. Our findings highlight an interaction between high temperatures and insecticide exposure, which suggests a need for including natural stressors, such as temperature, in pesticide risk assessments procedures.

Influence of high temperature and ethanol on thermostable lignocellulolytic enzymes

DEFF Research Database (Denmark)

Skovgaard, Pernille Anastasia; Jørgensen, Henning

2013-01-01

the influence of temperature and ethanol on enzyme activity and stability in the distillation step, where most enzymes are inactivated due to high temperatures. Two enzyme mixtures, a mesophilic and a thermostable mixture, were exposed to typical process conditions [temperatures from 55 to 65 °C and up to 5...... % ethanol (w/v)] followed by specific enzyme activity analyses and SDS-PAGE. The thermostable and mesophilic mixture remained active at up to 65 and 55 °C, respectively. When the enzyme mixtures reached their maximum temperature limit, ethanol had a remarkable influence on enzyme activity, e.g., the more...... ethanol, the faster the inactivation. The reason could be the hydrophobic interaction of ethanol on the tertiary structure of the enzyme protein. The thermostable mixture was more tolerant to temperature and ethanol and could therefore be a potential candidate for recycling after distillation....

Nucleon-nucleon interaction of a chiral σ-ω model at finite temperature

International Nuclear Information System (INIS)

Rukeng Su

1994-01-01

By using the imaginery time Green's function method, the nucleon-nucleon interaction of the chiral σ-ω model has been investigated under the one-loop approximation. The effective masses of the pion, σ-meson and ω-meson at finite temperature are given. We have found that the potential well of the nucleon-nucleon interaction becomes shallow as the temperature increases. At a critical temperature T c (70 MEV) the potential well disappears. (author)

High temperature oxidation of slurry coated interconnect alloys

DEFF Research Database (Denmark)

Persson, Åsa Helen

with this interaction mechanism mainly give a geometrical protection against oxidation by blocking oxygen access at the surface of the oxide scale. The protecting effect is gradually reduced as the oxide scale grows thicker than the diameter of the coating particles. Interaction mechanism B entails a chemical reaction...... scale. The incorporated coating particles create a geometrical protection against oxidation that should not loose their effect after the oxide scale has grown thicker than the diameter of the coating particles. The two single layer coatings consisting of (La0.85Sr0.15)MnO3 + 10% excess Mn, LSM, and (La0......In this project, high temperature oxidation experiments of slurry coated ferritic alloys in atmospheres similar to the atmosphere found at the cathode in an SOFC were conducted. From the observations possible interaction mechanisms between the slurry coatings and the growing oxide scale...

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

Evaluation of high temperature pressure sensors

International Nuclear Information System (INIS)

Choi, In-Mook; Woo, Sam-Yong; Kim, Yong-Kyu

2011-01-01

It is becoming more important to measure the pressure in high temperature environments in many industrial fields. However, there is no appropriate evaluation system and compensation method for high temperature pressure sensors since most pressure standards have been established at room temperature. In order to evaluate the high temperature pressure sensors used in harsh environments, such as high temperatures above 250 deg. C, a specialized system has been constructed and evaluated in this study. The pressure standard established at room temperature is connected to a high temperature pressure sensor through a chiller. The sensor can be evaluated in conditions of changing standard pressures at constant temperatures and of changing temperatures at constant pressures. According to the evaluation conditions, two compensation methods are proposed to eliminate deviation due to sensitivity changes and nonlinear behaviors except thermal hysteresis.

Interactive effect of temperature and CO2 increase in Arctic phytoplankton

Directory of Open Access Journals (Sweden)

Alexandra eCoello-Camba

2014-10-01

Full Text Available An experiment was performed in order to analyze the effects of the increase in water temperature and CO2 partial pressure expected for the end of this century in a present phytoplankton community inhabiting the Arctic Ocean. We analyzed both factors acting independently and together, to test possible interactions between them. The arctic planktonic community was incubated under 6 different treatments combining three experimental temperatures (1 ºC, 6 ºC and 10 ºC with two different CO2 levels of 380 ppm or 1000 ppm, at the UNIS installations in Longyearbyen (Svalbard, in summer 2010. Under warmer temperatures, a decrease in chlorophyll a concentration, biovolume and primary production was found, together with a shift in community structure towards a dominance of smaller cells (nano-sized. Effects of increased pCO2 were more modest, and although interactions were weak, our results suggest antagonistic interactive effects amongst increased temperature and CO2 levels, as elevated CO2 compensated partially the decrease in phytoplankton biomass induced by temperature in some groups. Interactions between the two stressors were generally weak, but elevated CO2 was observed to lead to a stepper decline in primary production with warming. Our results also suggest that future increases in water temperature and pCO2 would lead to a decrease in the community chl a concentration and biomass in the Arctic phytoplankton communities examined, leading to communities dominated by smaller nano-phytoplankton groups, with important consequences for the flow of carbon and food web dynamics.

High field magnetic anisotropy in praseodymium gallium garnet at low temperatures

International Nuclear Information System (INIS)

Wang Wei; Yue Yuan; Liu Gongqiang

2011-01-01

Research highlights: → A detailed analysis of crystal field effect is presented, and a set of new crystal field parameters is given to study the magnetic behaviors of the paramagnetic praseodymium gallium garnet (PrGaG). → The contribution of the exchange interaction between the praseodymium ions to the magnetic properties of PrGaG is further explored. Meanwhile, some characteristics of exchange interaction are revealed. → With the consideration of crystal field and exchange interaction, the available experiments are successfully fitted by our theoretical model. → Our theory suggests that PrGaG is ferromagnetic ordering at low temperatures, and the exchange interaction is anisotropic. - Abstract: In this paper, with the consideration of crystal field and exchange interaction between the rare-earth Pr 3+ ions, the magnetic anisotropy in praseodymium gallium garnet (PrGaG) in high magnetic fields and at low temperatures is theoretically analyzed. A set of relatively suitable CF parameters is obtained by studying the influence of the variations of nine CF parameters on the magnetization. However, only taking crystal field effect into account, theoretical calculations indicate that the experiments cannot be excellently interpreted. Then, the exchange interaction between Pr 3+ ion, which can be described as an effective exchange field H v = vM = vχH e = ηH e , is further considered. On the other hand, by evaluating the variation of the parameter η with the magnetic fields, our theory implies that PrGaG exhibits ferrimagnetic ordering at low temperatures, and the exchange interaction in PrGaG displays obvious anisotropy. Also, the theoretical data show better agreements with the experimental results.

The temperature pulse propagation in interacting nuclear slabs

International Nuclear Information System (INIS)

Kozlowski, M.; Zurich Univ.

1989-01-01

Following the method developed by R.J. Swenson a non-Fourier equation for heat transfer in nuclear matter is obtained. The velocity of heat propagation is calculated and the value υ s = υ F /√3 is obtained. For two interacting nuclear slabs the temperature as a function of time is calculated. For a nucleon mean free path λ ≅ 3 fm the temperature saturation time is calculated and the value ≅ 160 fm/c is obtained. (orig.)

Mechanism of high-temperature background of internal friction in metals

International Nuclear Information System (INIS)

Shapoval, B.I.; Arzhavitin, V.M.

1988-01-01

Data of theoretical and experimental studies on energy dissipation in vibrating metal at small amplitudes and elevated temperatures (high temperature background of internal friction) are generalized and systematized. Evolution of knowledge of the background as a phenomenon influenced mainly by crystal structure defects - their form, quantity, mobility and interaction is followed. Considered is a wide range of investigated metal states and measurement conditions, and interrelations with other characteristics, for instance, strength ones. On the basis of the data obtained by authors and other investigations a concept of an additional third stage of the background increase with the temperature - the stage of deviation from exponential dependence at premelting point, is introduced. 107 refs.; 32 figs.; 3 tabs

High temperature compression tests performed on doped fuels

International Nuclear Information System (INIS)

Duguay, C.; Mocellin, A.; Dehaudt, P.; Fantozzi, G.

1997-01-01

The use of additives of corundum structure M 2 O 3 (M=Cr, Al) is an effective way of promoting grain growth of uranium dioxide. The high-temperature compressive deformation of large-grained UO 2 doped with these oxides has been investigated and compared with that of pure UO 2 with a standard microstructure. Such doped fuels are expected to exhibit enhanced plasticity. Their use would therefore reduce the pellet-cladding mechanical interaction and thus improve the performances of the nuclear fuel. (orig.)

Monoterpene and sesquiterpene emissions from Quercus coccifera exhibit interacting responses to light and temperature

Directory of Open Access Journals (Sweden)

M. Staudt

2011-09-01

experiments, decreases of MT-hc emissions under high temperatures were correlated with decreases in CO2-assimilation and/or photosynthetic electron transport. We conclude that light and temperature can have interactive short-term effects on the quantity and quality of BVOC emissions from Q. coccifera through substrate limitations of MT biosynthesis occurring at temperatures supraoptimal for photosynthetic processes that are exacerbated by oxidative stress and membrane damages. Such interactive effects are likely to occur frequently during hot and dry summers and simulations made in this work showed that they may have important consequences for emission predictions.

High-temperature plastic flow of a precipitation-hardened FeCoNiCr high entropy alloy

Energy Technology Data Exchange (ETDEWEB)

He, J.Y.; Wang, H.; Wu, Y.; Liu, X.J. [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China); Nieh, T.G. [Department of Materials Science and Engineering, the University of Tennessee, Knoxville, TN 37996 (United States); Lu, Z.P., E-mail: luzhaoping@163.com [State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing, Beijing 100083 (China)

2017-02-16

In this work, we systematically investigated flow behavior of a high entropy alloy (HEA) strengthened by coherent γ′ precipitates in the temperature range of 1023–1173 K. In contrast to the single-phase FeCoNiCrMn HEA, this precipitate-hardened alloy, i.e., (FeCoNiCr){sub 94}Ti{sub 2}Al{sub 4}, exhibited large reduction of the steady-state strain rate (by ~2 orders of magnitude) or drastic enhancement in flow stress, indicating significant improvement in high-temperature properties. Our results showed that the deformation could be divided into two regimes. At temperatures below 1123 K, coherent γ′ precipitates effectively blocked the dislocation motion, thus resulted in a threshold stress effect. Above 1123 K, however, γ′ particles dissolved and the deformation was controlled by the ordinary dislocation climb mechanism. In addition, we conducted transmission electron microscopy to characterize dislocation-precipitate interaction to provide microstructural evidences to support our conclusion of the specific deformation mechanisms in the two temperature regimes.

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

Science.gov (United States)

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

Interactive effects of temperature, food and skeletal mineralogy mediate biological responses to ocean acidification in a widely distributed bryozoan.

Science.gov (United States)

Swezey, Daniel S; Bean, Jessica R; Ninokawa, Aaron T; Hill, Tessa M; Gaylord, Brian; Sanford, Eric

2017-04-26

Marine invertebrates with skeletons made of high-magnesium calcite may be especially susceptible to ocean acidification (OA) due to the elevated solubility of this form of calcium carbonate. However, skeletal composition can vary plastically within some species, and it is largely unknown how concurrent changes in multiple oceanographic parameters will interact to affect skeletal mineralogy, growth and vulnerability to future OA. We explored these interactive effects by culturing genetic clones of the bryozoan Jellyella tuberculata (formerly Membranipora tuberculata ) under factorial combinations of dissolved carbon dioxide (CO 2 ), temperature and food concentrations. High CO 2 and cold temperature induced degeneration of zooids in colonies. However, colonies still maintained high growth efficiencies under these adverse conditions, indicating a compensatory trade-off whereby colonies degenerate more zooids under stress, redirecting energy to the growth and maintenance of new zooids. Low-food concentration and elevated temperatures also had interactive effects on skeletal mineralogy, resulting in skeletal calcite with higher concentrations of magnesium, which readily dissolved under high CO 2 For taxa that weakly regulate skeletal magnesium concentration, skeletal dissolution may be a more widespread phenomenon than is currently documented and is a growing concern as oceans continue to warm and acidify. © 2017 The Author(s).

High temperature materials

International Nuclear Information System (INIS)

2003-01-01

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

High-temperature materials and structural ceramics

International Nuclear Information System (INIS)

1990-01-01

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

Passive Resistor Temperature Compensation for a High-Temperature Piezoresistive Pressure Sensor.

Science.gov (United States)

Yao, Zong; Liang, Ting; Jia, Pinggang; Hong, Yingping; Qi, Lei; Lei, Cheng; Zhang, Bin; Li, Wangwang; Zhang, Diya; Xiong, Jijun

2016-07-22

The main limitation of high-temperature piezoresistive pressure sensors is the variation of output voltage with operating temperature, which seriously reduces their measurement accuracy. This paper presents a passive resistor temperature compensation technique whose parameters are calculated using differential equations. Unlike traditional experiential arithmetic, the differential equations are independent of the parameter deviation among the piezoresistors of the microelectromechanical pressure sensor and the residual stress caused by the fabrication process or a mismatch in the thermal expansion coefficients. The differential equations are solved using calibration data from uncompensated high-temperature piezoresistive pressure sensors. Tests conducted on the calibrated equipment at various temperatures and pressures show that the passive resistor temperature compensation produces a remarkable effect. Additionally, a high-temperature signal-conditioning circuit is used to improve the output sensitivity of the sensor, which can be reduced by the temperature compensation. Compared to traditional experiential arithmetic, the proposed passive resistor temperature compensation technique exhibits less temperature drift and is expected to be highly applicable for pressure measurements in harsh environments with large temperature variations.

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

Interactive effects of temperature and food availability on the growth of Arctica islandica (Bivalvia) juveniles.

Science.gov (United States)

Ballesta-Artero, Irene; Janssen, Reneé; van der Meer, Jaap; Witbaard, Rob

2018-02-01

The interest in Arctica islandica growth biology has recently increased due to the widespread use of its shell as a bioarchive. Although temperature and food availability are considered key factors in its growth, their combined influence has not been studied so far under laboratory conditions. We tested the interactive effect of temperature and food availability on the shell and tissue growth of A. islandica juveniles (9-15 mm in height) in a multi-factorial experiment with four food levels (no food, low, medium, and high) and three different temperatures (3, 8, 13 °C). Shell and tissue growth were observed in all treatments, with significant differences occurring only among food levels (2-way ANOVA; P-value food, and the interaction between them (2-way ANOVA; P-value < 0.05). Siphon observations, as indication of feeding activities, played a key role to better understand the growth variation between individuals. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

Science.gov (United States)

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

2018-04-01

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

Anomalous van der Waals-Casimir interactions on graphene: A concerted effect of temperature, retardation, and non-locality

Science.gov (United States)

Ambrosetti, Alberto; Silvestrelli, Pier Luigi

2018-04-01

Dispersion forces play a major role in graphene, largely influencing adhesion of adsorbate moieties and stabilization of functional multilayered structures. However, the reliable prediction of dispersion interactions on graphene up to the relevant ˜10 nm scale is an extremely challenging task: in fact, electromagnetic retardation effects and the highly non-local character of π electrons can imply sizeable qualitative variations of the interaction with respect to known pairwise approaches. Here we address both issues, determining the finite-temperature van der Waals (vdW)-Casimir interaction for point-like and extended adsorbates on graphene, explicitly accounting for the non-local dielectric permittivity. We find that temperature, retardation, and non-locality play a crucial role in determining the actual vdW scaling laws and the stability of both atomic and larger molecular adsorbates. Our results highlight the importance of these effects for a proper description of systems of current high interest, such as graphene interacting with biomolecules, and self-assembly of complex nanoscale structures. Due to the generality of our approach and the observed non-locality of other 2D materials, our results suggest non-trivial vdW interactions from hexagonal mono-layered materials from group 14 of the periodic table, to transition metal dichalcogenides.

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.

High Temperature, High Power Piezoelectric Composite Transducers

Science.gov (United States)

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

2014-01-01

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

High temperature compression tests performed on doped fuels

Energy Technology Data Exchange (ETDEWEB)

Duguay, C.; Mocellin, A.; Dehaudt, P. [Commissariat a l`Energie Atomique, CEA Grenoble (France); Fantozzi, G. [INSA Lyon - GEMPPM, Villeurbanne (France)

1997-12-31

The use of additives of corundum structure M{sub 2}O{sub 3} (M=Cr, Al) is an effective way of promoting grain growth of uranium dioxide. The high-temperature compressive deformation of large-grained UO{sub 2} doped with these oxides has been investigated and compared with that of pure UO{sub 2} with a standard microstructure. Such doped fuels are expected to exhibit enhanced plasticity. Their use would therefore reduce the pellet-cladding mechanical interaction and thus improve the performances of the nuclear fuel. (orig.) 5 refs.

Green frequency-doubled laser-beam propagation in high-temperature hohlraum plasmas.

Science.gov (United States)

Niemann, C; Berger, R L; Divol, L; Froula, D H; Jones, O; Kirkwood, R K; Meezan, N; Moody, J D; Ross, J; Sorce, C; Suter, L J; Glenzer, S H

2008-02-01

We demonstrate propagation and small backscatter losses of a frequency-doubled (2omega) laser beam interacting with inertial confinement fusion hohlraum plasmas. The electron temperature of 3.3 keV, approximately a factor of 2 higher than achieved in previous experiments with open geometry targets, approaches plasma conditions of high-fusion yield hohlraums. In this new temperature regime, we measure 2omega laser-beam transmission approaching 80% with simultaneous backscattering losses of less than 10%. These findings suggest that good laser coupling into fusion hohlraums using 2omega light is possible.

High-temperature superconductivity

International Nuclear Information System (INIS)

Ginzburg, V.L.

1987-07-01

After a short account of the history of experimental studies on superconductivity, the microscopic theory of superconductivity, the calculation of the control temperature and its possible maximum value are presented. An explanation of the mechanism of superconductivity in recently discovered superconducting metal oxide ceramics and the perspectives for the realization of new high-temperature superconducting materials are discussed. 56 refs, 2 figs, 3 tabs

Casimir-Foucault interaction: Free energy and entropy at low temperature

Science.gov (United States)

Intravaia, Francesco; Ellingsen, Simen Å.; Henkel, Carsten

2010-09-01

It was recently found that thermodynamic anomalies which arise in the Casimir effect between metals described by the Drude model can be attributed to the interaction of fluctuating Foucault (or eddy) currents [F. Intravaia and C. Henkel, Phys. Rev. Lett.PRLTAO0031-900710.1103/PhysRevLett.103.130405 103, 130405 (2009).] We focus on the transverse electric (TE) polarization, where the anomalies occur, and show explicitly that the two leading terms of the low-temperature correction to the Casimir free energy of interaction between two plates are identical to those pertaining to the Foucault current interaction alone, up to a correction which is very small for good metals. Moreover, a mode density along real frequencies is introduced, showing that the TE contribution to the Casimir free energy, as given by the Lifshitz theory, separates in a natural manner into contributions from eddy currents and propagating cavity modes, respectively. The latter have long been known to be of little importance to the low-temperature Casimir anomalies. This convincingly demonstrates that eddy current modes are responsible for the large temperature correction to the Casimir effect between Drude metals, predicted by the Lifshitz theory, but not observed in experiments.

Casimir-Foucault interaction: Free energy and entropy at low temperature

International Nuclear Information System (INIS)

Intravaia, Francesco; Ellingsen, Simen A.; Henkel, Carsten

2010-01-01

It was recently found that thermodynamic anomalies which arise in the Casimir effect between metals described by the Drude model can be attributed to the interaction of fluctuating Foucault (or eddy) currents [F. Intravaia and C. Henkel, Phys. Rev. Lett. 103, 130405 (2009).] We focus on the transverse electric (TE) polarization, where the anomalies occur, and show explicitly that the two leading terms of the low-temperature correction to the Casimir free energy of interaction between two plates are identical to those pertaining to the Foucault current interaction alone, up to a correction which is very small for good metals. Moreover, a mode density along real frequencies is introduced, showing that the TE contribution to the Casimir free energy, as given by the Lifshitz theory, separates in a natural manner into contributions from eddy currents and propagating cavity modes, respectively. The latter have long been known to be of little importance to the low-temperature Casimir anomalies. This convincingly demonstrates that eddy current modes are responsible for the large temperature correction to the Casimir effect between Drude metals, predicted by the Lifshitz theory, but not observed in experiments.

Subcellular proteomic characterization of the high-temperature stress response of the cyanobacterium Spirulina platensis

Directory of Open Access Journals (Sweden)

Cheevadhanarak Supapon

2009-09-01

Full Text Available Abstract The present study examined the changes in protein expression in Spirulina platensis upon exposure to high temperature, with the changes in expression analyzed at the subcellular level. In addition, the transcriptional expression level of some differentially expressed proteins, the expression pattern clustering, and the protein-protein interaction network were analyzed. The results obtained from differential expression analysis revealed up-regulation of proteins involved in two-component response systems, DNA damage and repair systems, molecular chaperones, known stress-related proteins, and proteins involved in other biological processes, such as capsule formation and unsaturated fatty acid biosynthesis. The clustering of all differentially expressed proteins in the three cellular compartments showed: (i the majority of the proteins in all fractions were sustained tolerance proteins, suggesting the roles of these proteins in the tolerance to high temperature stress, (ii the level of resistance proteins in the photosynthetic membrane was 2-fold higher than the level in two other fractions, correlating with the rapid inactivation of the photosynthetic system in response to high temperature. Subcellular communication among the three cellular compartments via protein-protein interactions was clearly shown by the PPI network analysis. Furthermore, this analysis also showed a connection between temperature stress and nitrogen and ammonia assimilation.

High-temperature peridotites - lithospheric or asthenospheric?

International Nuclear Information System (INIS)

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

1990-01-01

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

Modeling interactive effects of Pb contamination, Ca"2"+ and Mg"2"+ on passivity of alloy 800 in simulated crevice chemistries at high temperature

International Nuclear Information System (INIS)

Lu, Baotong

2015-01-01

Highlights: • The capability of Pb impurity degrading the passivity of alloy 800 in high temperature water is much stronger than those of dissolved Ca/Mg salts. • The interactive effects of Pb-impurities and Ca/Mg salts on the passivity are likely a result competitive adsorption. • A phenomenological model to interpret the interactive effect of Pb-impurities and Ca/Mg salts on the passivity. - Abstract: A phenomenological model is postulated to interpret the interactive impacts of dissolved Pb contamination, Ca"2"+ and Mg"2"+ on passivity of Alloy 800 in simulated crevice chemistries at 300 °C. Passivity degradation is characterized by the retarded dehydration during passivation and increased donor density in passive film. Ca"2"+ and Mg"2"+ can cause the passivity degradation in the Pb-free chemistries but, if the Pb-contamination concentration exceeds a critical value, would reduce the detrimental effect of Pb-contamination. This behavior may be related to the extremely strong adsorption capacity of Pb contamination. Finally, the applications in the water management strategy of nuclear power plants are discussed.

High temperature corrosion of metals

International Nuclear Information System (INIS)

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

1988-08-01

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

Numerical study of droplet evaporation in coupled high-temperature and electrostatic fields

Directory of Open Access Journals (Sweden)

Ziwen Zuo

2015-03-01

Full Text Available The evaporation of a sessile water droplet under the coupled electrostatic and high-temperature fields is studied numerically. The leaky dielectric model and boiling point evaporation model are used for calculating the electric force and heat mass transfer. The free surface is captured using the volume of fluid method accounting for the variable surface tension and the transition of physical properties across the interface. The flow behaviors and temperature evolutions in different applied fields are predicted. It shows that in the coupled fields, the external electrostatic field restrains the flow inside the droplet and keeps a steady circulation. The flow velocity is reduced due to the interaction between electric body force and the force caused by temperature gradient. The heat transfer from air into the droplet is reduced by the lower flow velocity. The evaporation rate of the droplet in the high-temperature field is decreased.

The interacting effects of temperature and food chain length on trophic abundance and ecosystem function.

Science.gov (United States)

Beveridge, Oliver S; Humphries, Stuart; Petchey, Owen L

2010-05-01

1. While much is known about the independent effects of trophic structure and temperature on density and ecosystem processes, less is known about the interaction(s) between the two. 2. We manipulated the temperature of laboratory-based bacteria-protist communities that contained communities with one, two, or three trophic levels, and recorded species' densities and bacterial decomposition. 3. Temperature, food chain length and their interaction produced significant responses in microbial density and bacterial decomposition. Prey and resource density expressed different patterns of temperature dependency during different phases of population dynamics. The addition of a predator altered the temperature-density relationship of prey, from a unimodal trend to a negative one. Bacterial decomposition was greatest in the presence of consumers at higher temperatures. 4. These results are qualitatively consistent with a recent model of direct and indirect temperature effects on resource-consumer population dynamics. Results highlight and reinforce the importance of indirect effects of temperature mediated through trophic interactions. Understanding and predicting the consequences of environmental change will require that indirect effects, trophic structure, and individual species' tolerances be incorporated into theory and models.

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.

Advanced High Temperature Structural Seals

Science.gov (United States)

Newquist, Charles W.; Verzemnieks, Juris; Keller, Peter C.; Rorabaugh, Michael; Shorey, Mark

2002-10-01

This program addresses the development of high temperature structural seals for control surfaces for a new generation of small reusable launch vehicles. Successful development will contribute significantly to the mission goal of reducing launch cost for small, 200 to 300 pound payloads. Development of high temperature seals is mission enabling. For instance, ineffective control surface seals can result in high temperature (3100 F) flows in the elevon area exceeding structural material limits. Longer sealing life will allow use for many missions before replacement, contributing to the reduction of hardware, operation and launch costs.

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.)

Mottness in high-temperature copper-oxide superconductors

International Nuclear Information System (INIS)

Phillips, Philip; Choy, T.-P.; Leigh, Robert G

2009-01-01

The standard theory of metals, Fermi liquid theory, hinges on the key assumption that although the electrons interact, the low-energy excitation spectrum stands in a one-to-one correspondence with that of a non-interacting system. In the normal state of the copper-oxide high-temperature superconductors, drastic deviations from the Fermi liquid picture are obtained, highlighted by a pseudogap, broad spectral features and T-linear resistivity. A successful theory in this context must confront the highly constraining scaling argument which establishes that all 4-Fermi interactions are irrelevant (except for pairing) at a Fermi surface. This argument lays plain that new low-energy degrees of freedom are necessary. This paper focuses on the series of experiments on copper-oxide superconductors which reveal that the number of low-energy addition states per electron per spin exceeds unity, in direct violation of the key Fermi liquid tenet. These experiments point to new degrees of freedom, not made out of the elemental excitations, as the key mechanism by which Fermi liquid theory breaks down in the cuprates. A recent theoretical advance which permits an explicit integration of the high-energy scale in the standard model for the cuprates reveals the source of the new dynamical degrees of freedom at low energies, a charge 2e bosonic field which has nothing to do with pairing but rather represents the mixing with the high-energy scales. We demonstrate explicitly that at half-filling, this new degree of freedom provides a dynamical mechanism for the generation of the charge gap and antiferromagnetism in the insulating phase. At finite doping, many of the anomalies of the normal state of the cuprates including the pseudogap, T-linear resistivity and the mid-infrared band are reproduced. A possible route to superconductivity is explored

Measuring the internal temperature of a levitated nanoparticle in high vacuum

Science.gov (United States)

Hebestreit, Erik; Reimann, René; Frimmer, Martin; Novotny, Lukas

2018-04-01

The interaction of an object with its surrounding bath can lead to a coupling between the object's internal degrees of freedom and its center-of-mass motion. This coupling is especially important for nanomechanical oscillators, which are among the most promising systems for preparing macroscopic objects in quantum mechanical states. Here we exploit this coupling to derive the internal temperature of a levitated nanoparticle from measurements of its center-of-mass dynamics. For a laser-trapped silica particle in high vacuum, we find an internal temperature of 1000 (60 )K . The measurement and control of the internal temperature of nanomechanical oscillators is of fundamental importance because black-body emission sets limits to the coherence of macroscopic quantum states.

Development of NONSTA code for the design and analysis of LMR high temperature structure

International Nuclear Information System (INIS)

Kim, Jong Bum; Lee, H. Y.; Yoo, B.

1999-02-01

Liquid metal reactor(LMR) operates at high temperature (500-550 dg C) and structural materials undergo complex deformation behavior like diffusion, dislocation glide, and dislocation climb due to high temperature environment. And the material life reduces rapidly due to the interaction of cavities created inside structural materials and high temperature fatigue cracks. Thus the establishment of high temperature structure analysis techniques is necessary for the reliability and safety evaluation of such structures. The objectives of this study are to develop NONSTA code as the subprogram of ABAQUS code adopting constitutive equations which can predict high temperature material behavior precisely and to build the systematic analysis procedures. The developed program was applied to the example problems such as the tensile analysis using exponential creep model and the repetitive tensile-compression analysis using Chaboche unified viscoplastic model. In addition, the problem of a plate with a center hole subjected to tensile load was solved to show the applicability of the program to multiaxial problem and the time dependent stress redistribution was observed. (Author). 40 refs., 2 tabs., 24 figs

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

Cluster-assembled overlayers and high-temperature superconductors

International Nuclear Information System (INIS)

Ohno, T.R.; Yang, Y.; Kroll, G.H.; Krause, K.; Schmidt, L.D.; Weaver, J.H.; Kimachi, Y.; Hidaka, Y.; Pan, S.H.; de Lozanne, A.L.

1991-01-01

X-ray photoemission results for interfaces prepared by cluster assembly with nanometer-size clusters deposited on high-T c superconductors (HTS's) show a reduction in reactivity because atom interactions with the surface are replaced by cluster interactions. Results for conventional atom deposition show the formation of overlayer oxides that are related to oxygen depletion and disruption of the near-surface region of the HTS's. For cluster assembly of Cr and Cu, there is a very thin reacted region on single-crystal Bi 2 Sr 2 CaCu 2 O 8 . Reduced reactivity is observed for Cr cluster deposition on single-crystal YBa 2 Cu 3 O 7 -based interfaces. There is no evidence of chemical modification of the surface for Ge and Au cluster assembly on Bi 2 Sr 2 CaCu 2 O 8 (100). The overlayer grown by Au cluster assembly on Bi 2 Sr 2 CaCu 2 O 8 covers the surface at low temperature but roughening occurs upon warming to 300 K. Scanning-tunneling-microscopy results for the Au(cluster)/Bi 2 Sr 2 CaCu 2 O 8 system warmed to 300 K shows individual clusters that have coalesced into large clusters. These results offer insight into the role of surface energies and cluster interactions in determining the overlayer morphology. Transmission-electron-microscopy results for Cu cluster assembly on silica show isolated irregularly shaped clusters that do not interact at low coverage. Sintering and labyrinth formation is observed at intermediate coverage and, ultimately, a continuous film is achieved at high coverage. Silica surface wetting by Cu clusters demonstrates that dispersive force are important for these small clusters

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.

Preliminary Guideline for the High Temperature Structure Integrity Assessment Procedure Part II. High Temperature Structural Integrity Assessment

Energy Technology Data Exchange (ETDEWEB)

Lee, Jae Han; Kim, J. B.; Lee, H. Y.; Park, C. G.; Joo, Y. S.; Koo, G. H.; Kim, S. H

2007-02-15

A high temperature structural integrity assessment belongs to the Part II of a whole preliminary guideline for the high temperature structure. The main contents of this guideline are the evaluation procedures of the creep-fatigue crack initiation and growth in high temperature condition, the high temperature LBB evaluation procedure, and the inelastic evaluations of the welded joints in SFR structures. The methodologies for the proper inelastic analysis of an SFR structures in high temperatures are explained and the guidelines of inelastic analysis options using ANSYS and ABAQUS are suggested. In addition, user guidelines for the developed NONSTA code are included. This guidelines need to be continuously revised to improve the applicability to the design and analysis of the SFR structures.

High temperature thermometric phosphors

Science.gov (United States)

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

1999-03-23

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

High-temperature compatibility between liquid metal as PWR fuel gap filler and stainless steel and high-density concrete

Science.gov (United States)

Wongsawaeng, Doonyapong; Jumpee, Chayanit; Jitpukdee, Manit

2014-08-01

In conventional nuclear fuel rods for light-water reactors, a helium-filled as-fabricated gap between the fuel and the cladding inner surface accommodates fuel swelling and cladding creep down. Because helium exhibits a very low thermal conductivity, it results in a large temperature rise in the gap. Liquid metal (LM; 1/3 weight portion each of lead, tin, and bismuth) has been proposed to be a gap filler because of its high thermal conductivity (∼100 times that of He), low melting point (∼100 °C), and lack of chemical reactivity with UO2 and water. With the presence of LM, the temperature drop across the gap is virtually eliminated and the fuel is operated at a lower temperature at the same power output, resulting in safer fuel, delayed fission gas release and prevention of massive secondary hydriding. During normal reactor operation, should an LM-bonded fuel rod failure occurs resulting in a discharge of liquid metal into the bottom of the reactor pressure vessel, it should not corrode stainless steel. An experiment was conducted to confirm that at 315 °C, LM in contact with 304 stainless steel in the PWR water chemistry environment for up to 30 days resulted in no observable corrosion. Moreover, during a hypothetical core-melt accident assuming that the liquid metal with elevated temperature between 1000 and 1600 °C is spread on a high-density concrete basement of the power plant, a small-scale experiment was performed to demonstrate that the LM-concrete interaction at 1000 °C for as long as 12 h resulted in no penetration. At 1200 °C for 5 h, the LM penetrated a distance of ∼1.3 cm, but the penetration appeared to stop. At 1400 °C the penetration rate was ∼0.7 cm/h. At 1600 °C, the penetration rate was ∼17 cm/h. No corrosion based on chemical reactions with high-density concrete occurred, and, hence, the only physical interaction between high-temperature LM and high-density concrete was from tiny cracks generated from thermal stress. Moreover

High temperature pipeline design

Energy Technology Data Exchange (ETDEWEB)

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

2004-07-01

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

Contribution of thermodynamics in the understanding of the physico-chemical behaviour of fuels at high temperature

International Nuclear Information System (INIS)

Gueneau, C.; Chatain, S.; Gosse, S.; Dumas, J.C.; Defoort, F.

2006-01-01

The thermodynamic approach for studying the physico-chemical behaviour of nuclear fuels at high temperature is presented. For instance is shown how the thermodynamic study of the uranium-oxygen-zirconium-iron system has contributed to improve the understanding of the scenario considered in studies on serious accidents for PWR reactors. Concerning the fuels of the future high temperature reactors, has been developed a thermodynamic data base 'fuelbase' (U-Pu-O-C-N-Si-Zr-Ti-Mo-Cr) using the Calphad method in parallel with experimental studies. In the framework of the studies on high temperature reactors, experimental works on the study of the interaction between the uranium dioxide and graphite are presented. This interaction leads to the formation of gaseous CO and CO 2 which can potentially be prejudicial to the thermomechanical resistance of the fuel in reactor. In this framework, the thermodynamic properties of the uranium-oxygen-carbon system are studied. (O.M.)

Development and evaluation of high temperature materials for power plant

International Nuclear Information System (INIS)

Nickel, H.; Schubert, F.

1992-01-01

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

High-Temperature Corrosion Behavior of Alloy 617 in Helium Environment of Very High Temperature Gas Reactor

International Nuclear Information System (INIS)

Lee, Gyeong-Geun; Jung, Sujin; Kim, Daejong; Jeong, Yong-Whan; Kim, Dong-Jin

2012-01-01

Alloy 617 is a Ni-base superalloy and a candidate material for the intermediate heat exchanger (IHX) of a very high temperature gas reactor (VHTR) which is one of the next generation nuclear reactors under development. The high operating temperature of VHTR enables various applications such as mass production of hydrogen with high energy efficiency. Alloy 617 has good creep resistance and phase stability at high temperatures in an air environment. However, it was reported that the mechanical properties decreased at a high temperature in an impure helium environment. In this study, high-temperature corrosion tests were carried out at 850°C-950°C in a helium environment containing the impurity gases H_2, CO, and CH_4, in order to examine the corrosion behavior of Alloy 617. Until 250 h, Alloy 617 specimens showed a parabolic oxidation behavior at all temperatures. The activation energy for oxidation in helium environment was 154 kJ/mol. The SEM and EDS results elucidated a Cr-rich surface oxide layer, Al-rich internal oxides and depletion of grain boundary carbides. The thickness and depths of degraded layers also showed a parabolic relationship with time. A normal grain growth was observed in the Cr-rich surface oxide layer. When corrosion tests were conducted in a pure helium environment, the oxidation was suppressed drastically. It was elucidated that minor impurity gases in the helium would have detrimental effects on the high temperature corrosion behavior of Alloy 617 for the VHTR application.

Molecular-dynamics method for the simulation of bulk-solid interfaces at high temperatures

International Nuclear Information System (INIS)

Lutsko, J.F.; Wolf, D.; Yip, S.; Phillpot, S.R.; Nguyen, T.

1988-01-01

A new method for the molecular-dynamics simulation of bulk planar interfaces at high temperatures is presented. The method uses the basic Parrinello-Rahman (constant-stress) scheme, modified for the application to inhomogeneous systems. Since our computational cell contains only one interface with two-dimensional (2D) periodic border conditions, we are able to study isolated interfaces all the way up to melting. The interaction between boundaries which may lead to their annihilation at higher temperatures, which is a problem when 3D periodic borders are applied, is thus avoided. As an application, the method is used to study the stability of a grain boundary at high temperatures. Observations on a possible connection between grain-boundary migration and ''premelting'' are discussed

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

Science.gov (United States)

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.

Identifying the genes of unconventional high temperature superconductors.

Science.gov (United States)

Hu, Jiangping

We elucidate a recently emergent framework in unifying the two families of high temperature (high [Formula: see text]) superconductors, cuprates and iron-based superconductors. The unification suggests that the latter is simply the counterpart of the former to realize robust extended s-wave pairing symmetries in a square lattice. The unification identifies that the key ingredients (gene) of high [Formula: see text] superconductors is a quasi two dimensional electronic environment in which the d -orbitals of cations that participate in strong in-plane couplings to the p -orbitals of anions are isolated near Fermi energy. With this gene, the superexchange magnetic interactions mediated by anions could maximize their contributions to superconductivity. Creating the gene requires special arrangements between local electronic structures and crystal lattice structures. The speciality explains why high [Formula: see text] superconductors are so rare. An explicit prediction is made to realize high [Formula: see text] superconductivity in Co/Ni-based materials with a quasi two dimensional hexagonal lattice structure formed by trigonal bipyramidal complexes.

High intensity laser interactions with sub-micron droplets

International Nuclear Information System (INIS)

Mountford, L.C.

1999-01-01

A high-density source of liquid ethanol droplets has been developed, characterised and used in laser interaction studies for the first time. Mie Scattering and attenuation measurements show that droplets with a radius of (0.5 ± 0.1) μm and atomic densities of 10 19 atoms/cm 3 can be produced, bridging the gap between clusters and macroscopic solids. Lower density (10 16 cm -3 ) sprays can also be produced and these are electrostatically split into smaller droplets with a radius of (0.3 ± 0.1) μm. This work has been accepted for publication in Review of Scientific Instruments. A range of high intensity interaction experiments have been carried out with this unique sub-micron source. The absolute yield of keV x-rays, generated using 527 nm, 2 ps pulses focused to ∼10 17 W/cm 2 , was measured for the first time. ∼7 μJ of x-rays with photon energies above 1 keV were produced, comparable to yields obtained from much higher Z Xenon clusters. At intensities ≤10 16 W/cm 2 the yield from droplets exceeds that from solid targets of similar Z. The droplet medium is debris free and self-renewing, providing a suitable x-ray source for lithographic techniques. Due to the spacing between the droplets, it was expected that the droplet plasma temperature would exceed that of a solid target plasma, which is typically limited by rapid heat conduction to <1 keV. Analysis of the x-ray data shows this to be true with a mean droplet plasma temperature of (2 ± 0.8) keV, and a number of measurements exceeding 5 keV (to appear in Applied Physics Letters). The absorption of high intensity laser pulses in the dense spray has been measured for the first time and this was found to be wavelength and polarisation independent and in excess of 60%. These first interaction measurements clearly indicate that there are significant differences between the laser heating of droplet, solid and cluster targets. (author)

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-09-01

Low temperature plasma (LTP) treatment of biological tissue is a promising path toward sterilization of bacteria due to its versatility and ability to operate under well-controlled and relatively mild conditions. The present collaborative research of an interdisciplinary team of investigators at University of Maryland, College Park (UMD), and University of California, Berkeley (UCB) focused on establishing our knowledge based with regard to low temperature plasma-induced chemical modifications in biomolecules that result in inactivation due to various plasma species, including ions, reactive radicals, and UV/VUV photons. The overall goals of the project were to identify and quantify the mechanisms by which low and atmospheric pressure plasma deactivates endotoxic biomolecules. Additionally, we wanted to understand the mechanism by which atmospheric pressure plasmas (APP) modify surfaces and how these modifications depend on the interaction of APP with the environment. Various low pressure plasma sources, a vacuum beam system and several atmospheric pressure plasma sources were used to accomplish this. In our work we elucidated for the first time the role of ions, VUV photons and radicals in biological deactivation of representative biomolecules, both in a UHV beam system and an inductively coupled, low pressure plasma system, and established the associated atomistic biomolecule changes. While we showed that both ions and VUV photons can be very efficient in deactivation of biomolecules, significant etching and/or deep modification (~200 nm) accompanied these biological effects. One of the most important findings in this work is the significant radical-induced deactivation and surface modification can occur with minimal etching. However, if radical fluxes and corresponding etch rates are relatively high, for example at atmospheric pressure, endotoxic biomolecule film inactivation may require near-complete removal of the film. These findings motivated further work at

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

Final Report - Low Temperature Combustion Chemistry And Fuel Component Interactions

Energy Technology Data Exchange (ETDEWEB)

Wooldridge, Margaret [Univ. of Michigan, Ann Arbor, MI (United States)

2017-02-24

Recent research into combustion chemistry has shown that reactions at “low temperatures” (700 – 1100 K) have a dramatic influence on ignition and combustion of fuels in virtually every practical combustion system. A powerful class of laboratory-scale experimental facilities that can focus on fuel chemistry in this temperature range is the rapid compression facility (RCF), which has proven to be a versatile tool to examine the details of fuel chemistry in this important regime. An RCF was used in this project to advance our understanding of low temperature chemistry of important fuel compounds. We show how factors including fuel molecular structure, the presence of unsaturated C=C bonds, and the presence of alkyl ester groups influence fuel auto-ignition and produce variable amounts of negative temperature coefficient behavior of fuel ignition. We report new discoveries of synergistic ignition interactions between alkane and alcohol fuels, with both experimental and kinetic modeling studies of these complex interactions. The results of this project quantify the effects of molecular structure on combustion chemistry including carbon bond saturation, through low temperature experimental studies of esters, alkanes, alkenes, and alcohols.

Low Temperature Hydrogen Antihydrogen Interactions

International Nuclear Information System (INIS)

Armour, E. A. G.; Chamberlain, C. W.

2001-01-01

In view of current interest in the trapping of antihydrogen (H-bar) atoms at low temperatures, we have carried out a full four-body variational calculation to determine s-wave elastic phase shifts for hydrogen antihydrogen scattering, using the Kohn Variational Principle. Terms outside the Born-Oppenheimer approximation have been taken into account using the formalism of Kolos and Wolniewicz. As far as we are aware, this is the first time that these terms have been included in an H H-bar scattering calculation. This is a continuation of earlier work on H-H-bar interactions. Preliminary results differ substantially from those calculated using the Born-Oppenheimer approximation. A method is outlined for reducing this discrepancy and taking the rearrangement channel into account.

Electron-dislocation interaction at low temperatures. Progress report

International Nuclear Information System (INIS)

1978-01-01

The interaction of mobile dislocations with electrons in copper and copper alloys has shown that dislocation motion in copper, at low temperature, can be treated as an analog of an underdamped oscillator. We have also shown that the viscous drag on mobile dislocations in type II superconductors can be treated as an acoustic attenuation of an elastic wave

Low Ambient Temperature and Intracerebral Hemorrhage: The INTERACT2 Study.

Directory of Open Access Journals (Sweden)

Danni Zheng

Full Text Available Rates of acute intracerebral hemorrhage (ICH increase in winter months but the magnitude of risk is unknown. We aimed to quantify the association of ambient temperature with the risk of ICH in the Intensive Blood Pressure Reduction in Acute Cerebral Haemorrhage Trial (INTERACT2 participants on an hourly timescale.INTERACT2 was an international, open, blinded endpoint, randomized controlled trial of patients with spontaneous ICH (<6h of onset and elevated systolic blood pressure (SBP, 150-220 mmHg assigned to intensive (target SBP <140 mmHg or guideline-recommended (SBP <180 mmHg BP treatment. We linked individual level hourly temperature to baseline data of 1997 participants, and performed case-crossover analyses using a distributed lag non-linear model with 24h lag period to assess the association of ambient temperature and risk of ICH. Results were presented as overall cumulative odds ratios (ORs and 95% CI.Low ambient temperature (≤10°C was associated with increased risks of ICH: overall cumulative OR was 1.37 (0.99-1.91 for 10°C, 1.92 (1.31-2.81 for 0°C, 3.13 (1.89-5.19 for -10°C, and 5.76 (2.30-14.42 for -20°C, as compared with a reference temperature of 20°C.There was no clear relation of low temperature beyond three hours after exposure. Results were consistent in sensitivity analyses.Exposure to low ambient temperature within several hours increases the risk of ICH.ClinicalTrials.gov NCT00716079.

Fusion blanket high-temperature heat transfer

International Nuclear Information System (INIS)

Fillo, J.A.

1983-01-01

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

Symmetry non-restoration at high temperature and supersymmetry

CERN Document Server

Dvali, Gia; Dvali, Gia

1996-01-01

We analyse the high temperature behaviour of softly broken supersymmetric theories taking into account the role played by effective non-renormalizable terms generated by the decoupling of superheavy degrees of freedom or the Planck scale physics. It turns out that discrete or continuous symmetries, spontaneously broken at intermediate scales, may never be restored, at least up to temperatures of the cutoff scale. There are a few interesting differences from the usual non-restoration in non-supersymmetric theories case where one needs at least two Higgs fields and non-restoration takes place for a range of parameters only. We show that with non-renormalizable interactions taken into account the non-restoration can occur for any nonzero range of parameters even for a single Higgs field. We show that such theories in general solve the cosmological domain wall problem, since the thermal production of the dangerous domain walls is enormously suppressed.

Computational study of a high-temperature thermal nanoimprint lithographic (TNIL) process

Science.gov (United States)

Cleveland, Nicolas Joseph

As an emerging manufacturing technique, nanoimprint lithography (NIL) can fabricate micro and nanoscale features of microfluidic devices at very high accuracy and reliability. The process parameters such as pressure, temperature, and material properties play critical roles in the NIL process. In this work, the process of thermal nanoimprint lithography (TNIL) is studied computationally and the developed model can accurately predict the nano and micro-pattern geometry and quality from TNIL processes based on complex mold-resist interaction. Applications of this modeling technique range from micro- and nano-patterns used in micro-channels for biomedical devices to other applications such as biological/particle sensors or superhydrophobic surfaces. In high-temperature TNIL process, a polymer melt such as polymethyl-methacrylate (PMMA) is heated beyond the melting temperature so that it behaves predominantly as a fluid during the imprint process. The effects of surface tension and shear thinning become significant at or above the melting point, whereas the polymer melt can be modeled as a viscoelastic solid, solved with finite element analysis, when process temperature remains between the glass transition and melting temperatures. Additionally, the mold used in TNIL can deform since it is made of soft-rubbery elastomer such as polydimethylsiloxane (PDMS), and it is of interest to include the effect of subsequent mold deformation. Leakage between channels or significant variation in channel width can occur in micro-fluidic devices if mold deformation exceeds design tolerances. In the current work, fluid-structure interaction (FSI) technology is leveraged to solve for significant mold deformation and its effect on the polymer melt flow field during TNIL process. The simulation result is compared to experimental results. The FSI simulation result is also compared to the equivalent case with a rigid mold in place of flexible material, which shows results of differing mold

A Delay Time Measurement of ULTRAS (Ultra-high Temperature Ultrasonic Response Analysis System) for a High Temperature Experiment

International Nuclear Information System (INIS)

Koo, Kil Mo; Kim, Sang Baik

2010-01-01

The temperature measurement of very high temperature core melt is of importance in a high temperature as the molten pool experiment in which gap formation between core melt and the reactor lower head, and the effect of the gap on thermal behavior are to be measured. The existing temperature measurement techniques have some problems, which the thermocouple, one of the contact methods, is restricted to under 2000 .deg. C, and the infrared thermometry, one of the non-contact methods, is unable to measure an internal temperature and very sensitive to the interference from reacted gases. In order to solve these problems, the delay time technique of ultrasonic wavelets due to high temperature has two sorts of stage. As a first stage, a delay time measurement of ULTRAS (Ultra-high Temperature Ultrasonic Response Analysis System) is suggested. As a second stage, a molten material temperature was measured up to 2300 .deg. C. Also, the optimization design of the UTS (ultrasonic temperature sensor) with persistence at the high temperature was suggested in this paper. And the utilization of the theory suggested in this paper and the efficiency of the developed system are performed by special equipment and some experiments supported by KRISS (Korea Research Institute of Standard and Science)

Competing magnetic interactions and low temperature magnetic phase transitions in composite multiferroics

International Nuclear Information System (INIS)

Borkar, Hitesh; Singh, V N; Kumar, Ashok; Choudhary, R J; Tomar, M; Gupta, Vinay

2015-01-01

Novel magnetic properties and magnetic interactions in composite multiferroic oxides Pb[(Zr 0.52 Ti 0.48 ) 0.60 (Fe 0.67 W 0.33 ) .40 ]O 3 ] 0.80 –[CoFe 2 O 4 ] 0.20 (PZTFW–CFO) have been studied from 50 to 1000 Oe field cooled (FC) and zero field cooled (ZFC) probing conditions, and over a wide range of temperatures (4–350 K). Crystal structure analysis, surface morphology, and high resolution transmission electron microscopy images revealed the presence of two distinct phases, where micro- and nano-size spinel CFO were embedded in tetragonal PZTFW matrix and applied a significant built-in compressive strain (∼0.4–0.8%). Three distinct magnetic phase transitions were observed with the subtle effect of CFO magnetic phase on PZTFW magnetic phase transitions below the blocking temperature (T B ). Temperature dependence magnetic property m(T) shows a clear evidence of spin freezing in magnetic order with lowering in thermal vibration. Chemical inhomogeneity and confinement of nanoscale ferrimagnetic phase in paramagnetic/antiferromagnetic matrix restrict the long range interaction of spin which in turn develop a giant spin frustration. A large divergence in the FC and ZFC data and broad hump in ZFC data near 200 (±10) K were observed which suggests that large magnetic anisotropy and short range order magnetic dipoles lead to the development of superparamagnetic states in composite. (paper)

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

Very-high-temperature reactors for future use

International Nuclear Information System (INIS)

Kasten, P.R.

1988-01-01

Very-High-Temperature Reactors (VHTRs) show promise for economic generation of electricity and of high-temperature process heat. The key is the development of high-temperature materials which permit gas turbine VHTRs to generate electricity economically, at helium temperatures which can be used for fossil fuel conversion processes. 7 refs., 5 figs

Very-high-temperature reactors for future use

International Nuclear Information System (INIS)

Kasten, P.R.

1988-08-01

Very-high-temperature reactors (VHTRs) show promise for economic generation of electricity and of high-temperature process heat. The key is the development of high-temperature materials which permit gas turbine VHTRs to generate electricity economically, at reactor coolant temperatures which can be used for fossil fuel conversion processes. 7 refs., 5 figs

Mediating water temperature increases due to livestock and global change in high elevation meadow streams of the Golden Trout Wilderness

Science.gov (United States)

Sebastien Nussle; Kathleen R. Matthews; Stephanie M. Carlson

2015-01-01

Rising temperatures due to climate change are pushing the thermal limits of many species, but how climate warming interacts with other anthropogenic disturbances such as land use remains poorly understood. To understand the interactive effects of climate warming and livestock grazing on water temperature in three high elevation meadow streams in the Golden Trout...

Investigation of high temperature reactions on solid substrates with Rutherford backscattering spectrometry: interaction of palladium with selenium on heated graphite surfaces

International Nuclear Information System (INIS)

Majidi, V.; Robertson, J.D.

1991-01-01

Selenium and palladium interactions on heated pyrolytically coated graphite substrates were investigated using Rutherford backscattering spectrometry. The studies were performed using selenium alone, palladium alone, and a combination of selenium and palladium deposited on the graphite substrates. The results indicate that palladium instantaneously stabilizes selenium at ambient temperatures and prevents the diffusion of selenium into the graphite. As the substrate is heated, temperature dependent diffusion of all analytes into the graphite is observed. Furthermore, it appears that the stabilization of selenium is due to the formation of a stoichiometric compound with palladium and oxygen. This compound decomposes at a temperature between 1070 and 1770 K. (author)

Investigation of high temperature reactions on solid substrates with Rutherford backscattering spectrometry: interaction of palladium with selenium on heated graphite surfaces

Energy Technology Data Exchange (ETDEWEB)

Majidi, V.; Robertson, J.D. (Kentucky Univ., Lexington, KY (United States). Dept. of Chemistry)

1991-01-01

Selenium and palladium interactions on heated pyrolytically coated graphite substrates were investigated using Rutherford backscattering spectrometry. The studies were performed using selenium alone, palladium alone, and a combination of selenium and palladium deposited on the graphite substrates. The results indicate that palladium instantaneously stabilizes selenium at ambient temperatures and prevents the diffusion of selenium into the graphite. As the substrate is heated, temperature dependent diffusion of all analytes into the graphite is observed. Furthermore, it appears that the stabilization of selenium is due to the formation of a stoichiometric compound with palladium and oxygen. This compound decomposes at a temperature between 1070 and 1770 K. (author).

High-temperature bulk acoustic wave sensors

International Nuclear Information System (INIS)

Fritze, Holger

2011-01-01

Piezoelectric crystals like langasite (La 3 Ga 5 SiO 14 , LGS) and gallium orthophosphate (GaPO 4 ) exhibit piezoelectrically excited bulk acoustic waves at temperatures of up to at least 1450 °C and 900 °C, respectively. Consequently, resonant sensors based on those materials enable new sensing approaches. Thereby, resonant high-temperature microbalances are of particular interest. They correlate very small mass changes during film deposition onto resonators or gas composition-dependent stoichiometry changes of thin films already deposited onto the resonators with the resonance frequency shift of such devices. Consequently, the objective of the work is to review the high-temperature properties, the operation limits and the measurement principles of such resonators. The electromechanical properties of high-temperature bulk acoustic wave resonators such as mechanical stiffness, piezoelectric and dielectric constant, effective viscosity and electrical conductivity are described using a one-dimensional physical model and determined accurately up to temperatures as close as possible to their ultimate limit. Insights from defect chemical models are correlated with the electromechanical properties of the resonators. Thereby, crucial properties for stable operation as a sensor under harsh conditions are identified to be the formation of oxygen vacancies and the bulk conductivity. Operation limits concerning temperature, oxygen partial pressure and water vapor pressure are given. Further, application-relevant aspects such as temperature coefficients, temperature compensation and mass sensitivity are evaluated. In addition, approximations are introduced which make the exact model handy for routine data evaluation. An equivalent electrical circuit for high-temperature resonator devices is derived based on the one-dimensional physical model. Low- and high-temperature approximations are introduced. Thereby, the structure of the equivalent circuit corresponds to the

High-temperature bulk acoustic wave sensors

Science.gov (United States)

Fritze, Holger

2011-01-01

Piezoelectric crystals like langasite (La3Ga5SiO14, LGS) and gallium orthophosphate (GaPO4) exhibit piezoelectrically excited bulk acoustic waves at temperatures of up to at least 1450 °C and 900 °C, respectively. Consequently, resonant sensors based on those materials enable new sensing approaches. Thereby, resonant high-temperature microbalances are of particular interest. They correlate very small mass changes during film deposition onto resonators or gas composition-dependent stoichiometry changes of thin films already deposited onto the resonators with the resonance frequency shift of such devices. Consequently, the objective of the work is to review the high-temperature properties, the operation limits and the measurement principles of such resonators. The electromechanical properties of high-temperature bulk acoustic wave resonators such as mechanical stiffness, piezoelectric and dielectric constant, effective viscosity and electrical conductivity are described using a one-dimensional physical model and determined accurately up to temperatures as close as possible to their ultimate limit. Insights from defect chemical models are correlated with the electromechanical properties of the resonators. Thereby, crucial properties for stable operation as a sensor under harsh conditions are identified to be the formation of oxygen vacancies and the bulk conductivity. Operation limits concerning temperature, oxygen partial pressure and water vapor pressure are given. Further, application-relevant aspects such as temperature coefficients, temperature compensation and mass sensitivity are evaluated. In addition, approximations are introduced which make the exact model handy for routine data evaluation. An equivalent electrical circuit for high-temperature resonator devices is derived based on the one-dimensional physical model. Low- and high-temperature approximations are introduced. Thereby, the structure of the equivalent circuit corresponds to the Butterworth

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...

High-temperature metallography setup

International Nuclear Information System (INIS)

Blumenfeld, M.; Shmarjahu, D.; Elfassy, S.

1979-06-01

A high-temperature metallography setup is presented. In this setup the observation of processes such as that of copper recrystallization was made possible, and the structure of metals such as uranium could be revealed. A brief historical review of part of the research works that have been done with the help of high temperature metallographical observation technique since the beginning of this century is included. Detailed description of metallographical specimen preparation technique and theoretical criteria based on the rate of evaporation of materials present on the polished surface of the specimens are given

High-temperature oxidation of tungsten covered by layer of glass-enamel melt

International Nuclear Information System (INIS)

Vasnetsova, V.B.; Shardakov, N.T.; Kudyakov, V.Ya.; Deryabin, V.A.

1997-01-01

Corrosion losses of tungsten covered by the layer of glass-enamel melt were determined at 800, 850, 900, 950 deg C. It is shown that the rate of high-temperature oxidation of tungsten decreases after application of glass-enamel melt on its surface. This is probably conditioned by reduction of area of metal interaction with oxidizing atmosphere

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.

Low Ambient Temperature and Intracerebral Hemorrhage: The INTERACT2 Study

Science.gov (United States)

Zheng, Danni; Arima, Hisatomi; Sato, Shoichiro; Gasparrini, Antonio; Heeley, Emma; Delcourt, Candice; Lo, Serigne; Huang, Yining; Wang, Jiguang; Stapf, Christian; Robinson, Thompson; Lavados, Pablo; Chalmers, John; Anderson, Craig S.

2016-01-01

Background Rates of acute intracerebral hemorrhage (ICH) increase in winter months but the magnitude of risk is unknown. We aimed to quantify the association of ambient temperature with the risk of ICH in the Intensive Blood Pressure Reduction in Acute Cerebral Haemorrhage Trial (INTERACT2) participants on an hourly timescale. Methods INTERACT2 was an international, open, blinded endpoint, randomized controlled trial of patients with spontaneous ICH (<6h of onset) and elevated systolic blood pressure (SBP, 150–220 mmHg) assigned to intensive (target SBP <140 mmHg) or guideline-recommended (SBP <180 mmHg) BP treatment. We linked individual level hourly temperature to baseline data of 1997 participants, and performed case-crossover analyses using a distributed lag non-linear model with 24h lag period to assess the association of ambient temperature and risk of ICH. Results were presented as overall cumulative odds ratios (ORs) and 95% CI. Results Low ambient temperature (≤10°C) was associated with increased risks of ICH: overall cumulative OR was 1.37 (0.99–1.91) for 10°C, 1.92 (1.31–2.81) for 0°C, 3.13 (1.89–5.19) for -10°C, and 5.76 (2.30–14.42) for -20°C, as compared with a reference temperature of 20°C.There was no clear relation of low temperature beyond three hours after exposure. Results were consistent in sensitivity analyses. Conclusions Exposure to low ambient temperature within several hours increases the risk of ICH. Trial Registration ClinicalTrials.gov NCT00716079 PMID:26859491

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...

Mechanical Property and Its Comparison of Superalloys for High Temperature Gas Cooled Reactor

International Nuclear Information System (INIS)

Kim, Woo Gon; Kim, D. W.; Ryu, W. S.; Han, C. H.; Yoon, J. H.; Chang, J.

2005-01-01

Since structural materials for high temperature gas cooled reactor are used during long period in nuclear environment up to 1000 .deg. C, it is important to have good properties at elevated temperature such as mechanical properties (tensile, creep, fatigue, creep-fatigue), microstructural stability, interaction between metal and gas, friction and wear, hydrogen and tritium permeation, irradiation behavior, corrosion by impurity in He. Thus, in order to select excellent materials for the high temperature gas cooled reactor, it is necessary to understand the material properties and to gather the data for them. In this report, the items related to material properties which are needed for designing the high temperature gas cooled reactor were presented. Mechanical properties; tensile, creep, and fatigue etc. were investigated for Haynes 230, Hastelloy-X, In 617 and Alloy 800H, which can be used as the major structural components, such as intermediate heat exchanger (IHX), hot duct and piping and internals. Effect of He and irradiation on these structural materials was investigated. Also, mechanical properties; physical properties, tensile properties, creep and creep crack growth rate were compared for them, respectively. These results of this report can be used as important data to select superior materials for high temperature gas reactor

Electron-phonon interaction and its manifestation in high-temperature superconductors

International Nuclear Information System (INIS)

Maksimov, E.G.

1995-01-01

Different types of band structure approaches for a description of electrons in systems with strong correlations are discussed. It is shown that all methods considered give different electron energy dispersions and Fermi surfaces. The good agreement between measured Fermi surfaces and those calculated by LDA shows that the spatial dispersion of the correlation interaction is not so important in HTSC systems. The same conclusion can be obtained from the optical and photoemission spectra. It is shown that the most important contribution beyond a band structure approach is given by an energy dependence of the electron self-energy. The most likely interaction responsible for this energy dependence is the electron-phonon one. Evidences about this fact are given

High mortality of Zostera marina under high temperature regimes but minor effects of the invasive macroalgae Gracilaria vermiculophylla

Science.gov (United States)

Höffle, H.; Thomsen, M. S.; Holmer, M.

2011-03-01

The present study tested for density-dependent effects of the invasive drift macroalgae Gracilaria vermiculophylla (Ohmi) Papenfuss on growth and survival of the native eelgrass, Zostera marina L., under different temperature levels. Three weeks laboratory experiments were conducted in Odense, Denmark, combining three algae densities (control, low 1.9 kg WW m -2, high 4.5 kg WW m -2) with typical Danish summer temperatures (18 °C) and elevated temperatures (21 °C and 27 °C). There was a significant effect of temperature on shoot survival with on average 68% mortality in the high temperature treatment but almost no mortality at the two lower temperatures. The higher mortality was probably caused by high sulphide levels in the sediment pore water (0.6 mmol l -1 at 18 °C compared to 3.7 mmol l -1 at 27 °C). Above-ground growth of the surviving shoots was also significantly affected by temperature, with leaf elongation rates being negatively affected, while the leaf plastochrone interval increased. Relative growth rate was significantly higher at 21 °C than at 18 °C or 27 °C, whereas rhizome elongation was significantly lowest at 27 °C. Elemental sulphur content in the plant tissues increased significantly with temperature and was up to 34 times higher (S 0 in rhizomes) at 27 °C compared to the lower temperatures. In contrast to the temperature effects, cover by G. vermiculophylla did not cause significant effects on any seagrass responses. However, there was a (non-significant) negative effect of algal cover at the highest temperature, where the seagrass is already stressed. The latter results suggest that more studies should test for interaction effects between temperature and other anthropogenic stressors given that temperature is predicted to increase in the near future.

On the evaluation of elastic follow-up of a high temperature discontinuous structure

International Nuclear Information System (INIS)

Lee, J. M.; Kim, J. B.; Lee, H. Y.; Lee, J. H.

2003-01-01

While high temperature structures of LMR experience inelastic deformation such as plasticity and creep due to high temperature operating temperature of 530∼550 .deg. C, geometric nonlinear structures may undergo elastic follow-up behavior due to the interaction between stiff region and weak region. Thus, careful consideration should be given to the design and analysis of high temperature geometric nonlinear structure. In this study, the elastic follow-up behavior of geometric nonlinear structure has been investigated and the current status of design method implemented in the ASME-NH, Japanese BDS, French RCC-MR, and UK R-5 codes to consider elastic follow-up behavior has been reviewed. It has been shown that the ratio of the stiff region and the weak region and the type of loading affect the elastic follow-up behavior greatly from the detailed inelastic analyses of two bar model and L-shaped structure subjected to various loading situation. The applicability and the conservatism of simplified analysis methods implemented among various design codes need to be studied further

Interaction domains in high performance NdFeB thick films

Energy Technology Data Exchange (ETDEWEB)

Woodcock, Tom; Khlopkov, Kirill; Schultz, Ludwig; Gutfleisch, Oliver [IFW Dresden, IMW, Dresden (Germany); Walther, Arno [Insitut Neel, CNRS-UJF, Grenoble (France); CEA Leti - MINATEC, Grenoble (France); Dempsey, Nora; Givord, Dominique [Insitut Neel, CNRS-UJF, Grenoble (France)

2009-07-01

Thick sputtered films (5-300 micron) of NdFeB have excellent hard magnetic properties which make them attractive for applications in micro-electro-mechanical systems (MEMS). A two step process consisting of triode sputtering and high temperature annealing produced films with energy densities approaching those of sintered NdFeB magnets. Magnetic force microscopy (MFM) using hard magnetic tips showed that the films deposited without substrate heating and at 300 C exhibited magnetic domains typical of low anisotropy materials. These films were amorphous in the as-deposited state. The film deposited at 500 C was crystalline and displaid hard magnetic properties. This was reflected in the magnetic microstructure which showed interaction domains typical of highly textured and high magnetic anisotropy materials with a grain size below or equal to the critical single-domain particle limit. With increasing substrate temperature, the domain patterns of the annealed films became coarser, indicating higher degrees of texture.

Raman spectroscopy in high temperature chemistry

International Nuclear Information System (INIS)

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

1979-01-01

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

Raman spectroscopy in high temperature chemistry

International Nuclear Information System (INIS)

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

1979-01-01

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

Stability of High Temperature Standard Platinum Resistance Thermometers at High Temperatures

OpenAIRE

Y. A. ABDELAZIZ; F. M. MEGAHED

2010-01-01

An investigation of the stability of high temperature standard platinum resistance thermometers HTSPRTs has been carried out for two different designs thermometers (with nominal resistance 0.25 Ω and 2.5 Ω) from two different suppliers. The thermometers were heated for more than 160 hours at temperatures above 960 0C using a vertical furnace with a ceramic block. A study was made of the influence of the heat treatment on the stability of the resistance at the triple point of water, and on the...

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.

High Temperature Transparent Furnace Development

Science.gov (United States)

Bates, Stephen C.

1997-01-01

This report describes the use of novel techniques for heat containment that could be used to build a high temperature transparent furnace. The primary objective of the work was to experimentally demonstrate transparent furnace operation at 1200 C. Secondary objectives were to understand furnace operation and furnace component specification to enable the design and construction of a low power prototype furnace for delivery to NASA in a follow-up project. The basic approach of the research was to couple high temperature component design with simple concept demonstration experiments that modify a commercially available transparent furnace rated at lower temperature. A detailed energy balance of the operating transparent furnace was performed, calculating heat losses through the furnace components as a result of conduction, radiation, and convection. The transparent furnace shells and furnace components were redesigned to permit furnace operation at at least 1200 C. Techniques were developed that are expected to lead to significantly improved heat containment compared with current transparent furnaces. The design of a thermal profile in a multizone high temperature transparent furnace design was also addressed. Experiments were performed to verify the energy balance analysis, to demonstrate some of the major furnace improvement techniques developed, and to demonstrate the overall feasibility of a high temperature transparent furnace. The important objective of the research was achieved: to demonstrate the feasibility of operating a transparent furnace at 1200 C.

Analysis of thermodynamic properties for high-temperature superconducting oxides

International Nuclear Information System (INIS)

Kushwah, S.S.; Shanker, J.

1993-01-01

Analysis of thermodynamic properties such as specific heat, Debye temperature, Einstein temperature, thermal expansion coefficient, bulk modulus, and Grueneisen parameter is performed for rare-earth-based, Tl-based, and Bi-based superconducting copper oxides. Values of thermodynamic parameters are calculated and reported. The relationship between the Debye temperature and the superconducting transition temperature is used to estimate the values of T c using the interaction parameters from Ginzburg. (orig.)

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

Separating heat stress from moisture stress: analyzing yield response to high temperature in irrigated maize

Science.gov (United States)

Carter, Elizabeth K.; Melkonian, Jeff; Riha, Susan J.; Shaw, Stephen B.

2016-09-01

Several recent studies have indicated that high air temperatures are limiting maize (Zea mays L.) yields in the US Corn Belt and project significant yield losses with expected increases in growing season temperatures. Further work has suggested that high air temperatures are indicative of high evaporative demand, and that decreases in maize yields which correlate to high temperatures and vapor pressure deficits (VPD) likely reflect underlying soil moisture limitations. It remains unclear whether direct high temperature impacts on yields, independent of moisture stress, can be observed under current temperature regimes. Given that projected high temperature and moisture may not co-vary the same way as they have historically, quantitative analyzes of direct temperature impacts are critical for accurate yield projections and targeted mitigation strategies under shifting temperature regimes. To evaluate yield response to above optimum temperatures independent of soil moisture stress, we analyzed climate impacts on irrigated maize yields obtained from the National Corn Growers Association (NCGA) corn yield contests for Nebraska, Kansas and Missouri. In irrigated maize, we found no evidence of a direct negative impact on yield by daytime air temperature, calculated canopy temperature, or VPD when analyzed seasonally. Solar radiation was the primary yield-limiting climate variable. Our analyses suggested that elevated night temperature impacted yield by increasing rates of phenological development. High temperatures during grain-fill significantly interacted with yields, but this effect was often beneficial and included evidence of acquired thermo-tolerance. Furthermore, genetics and management—information uniquely available in the NCGA contest data—explained more yield variability than climate, and significantly modified crop response to climate. Thermo-acclimation, improved genetics and changes to management practices have the potential to partially or completely

High temperature reaction kinetics

International Nuclear Information System (INIS)

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

1985-01-01

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

High-frequency applications of high-temperature superconductor thin films

Science.gov (United States)

Klein, N.

2002-10-01

High-temperature superconducting thin films offer unique properties which can be utilized for a variety of high-frequency device applications in many areas related to the strongly progressing market of information technology. One important property is an exceptionally low level of microwave absorption at temperatures attainable with low power cryocoolers. This unique property has initiated the development of various novel type of microwave devices and commercialized subsystems with special emphasis on application in advanced microwave communication systems. The second important achievement related to efforts in oxide thin and multilayer technology was the reproducible fabrication of low-noise Josephson junctions in high-temperature superconducting thin films. As a consequence of this achievement, several novel nonlinear high-frequency devices, most of them exploiting the unique features of the ac Josephson effect, have been developed and found to exhibit challenging properties to be utilized in basic metrology and Terahertz technology. On the longer timescale, the achievements in integrated high-temperature superconductor circuit technology may offer a strong potential for the development of digital devices with possible clock frequencies in the range of 100 GHz.

High-frequency applications of high-temperature superconductor thin films

International Nuclear Information System (INIS)

Klein, N.

2002-01-01

High-temperature superconducting thin films offer unique properties which can be utilized for a variety of high-frequency device applications in many areas related to the strongly progressing market of information technology. One important property is an exceptionally low level of microwave absorption at temperatures attainable with low power cryocoolers. This unique property has initiated the development of various novel type of microwave devices and commercialized subsystems with special emphasis on application in advanced microwave communication systems. The second important achievement related to efforts in oxide thin and multilayer technology was the reproducible fabrication of low-noise Josephson junctions in high-temperature superconducting thin films. As a consequence of this achievement, several novel nonlinear high-frequency devices, most of them exploiting the unique features of the ac Josephson effect, have been developed and found to exhibit challenging properties to be utilized in basic metrology and Terahertz technology. On the longer timescale, the achievements in integrated high-temperature superconductor circuit technology may offer a strong potential for the development of digital devices with possible clock frequencies in the range of 100 GHz. (author)

Temperature dependence of velocity of sound in high-Tc superconductors in normal state

International Nuclear Information System (INIS)

Bishoyi, K.C.; Rout, G.C.; Behera, S.N.

2002-01-01

A microscopic theoretical calculation of temperature dependence of velocity of sound in high temperature superconductors is addressed in this paper. The influence of model parameters of the system in its normal phase is investigated through numerical calculations. The results at the room temperature as well as low temperatures (∼ 25 K), are discussed. The dimensionless parameters involved in the calculations are the electron-phonon coupling (g), staggered magnetic field (h), hybridization (V), position of the f-level (d), temperature (t) and the conduction band width (ω). The model Hamiltonian contains the antiferromagnetism in conduction electrons of cooper and the electron-phonon interaction through the hybridization between conduction electrons and f-electrons of impurity atoms. The phonon Green's functions are calculated by Zubarev's technique. The velocity of sound is calculated in the long wavelength and finite temperature limit. (author)

Review on fatigue behavior of high-strength concrete after high temperature

Science.gov (United States)

Zhao, Dongfu; Jia, Penghe; Gao, Haijing

2017-06-01

The fatigue of high-strength concrete after high temperature has begun to attract attention. But so far the researches work about the fatigue of high-strength concrete after high temperature have not been reported. This article based on a large number of literature. The research work about the fatigue of high-strength concrete after high temperature are reviewed, analysed and expected, which can provide some reference for the experimental study of fatigue damage analysis.

Materials corrosion and protection at high temperatures

International Nuclear Information System (INIS)

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

2011-01-01

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

High-temperature uncertainty

International Nuclear Information System (INIS)

Timusk, T.

2005-01-01

Recent experiments reveal that the mechanism responsible for the superconducting properties of cuprate materials is even more mysterious than we thought. Two decades ago, Georg Bednorz and Alex Mueller of IBM's research laboratory in Zurich rocked the world of physics when they discovered a material that lost all resistance to electrical current at the record temperature of 36 K. Until then, superconductivity was thought to be a strictly low-temperature phenomenon that required costly refrigeration. Moreover, the IBM discovery - for which Bednorz and Mueller were awarded the 1987 Nobel Prize for Physics - was made in a ceramic copper-oxide material that nobody expected to be particularly special. Proposed applications for these 'cuprates' abounded. High-temperature superconductivity, particularly if it could be extended to room temperature, offered the promise of levitating trains, ultra-efficient power cables, and even supercomputers based on superconducting quantum interference devices. But these applications have been slow to materialize. Moreover, almost 20 years on, the physics behind this strange state of matter remains a mystery. (U.K.)

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.

Main and interaction effects of extrusion temperature and usage ...

African Journals Online (AJOL)

The extruded full fat soybean (EFFSB) may be used in diet to satisfy the energy and protein requirements of fast growing broiler chickens. The main and interaction effects of three extrusion temperatures and two dietary levels of FFSB were studied on the performance, physiological enzymes and blood metabolites of broiler ...

Nonreactive spreading at high temperature: molten metals and oxides on molybdenum.

Science.gov (United States)

Saiz, E; Tomsia, A P; Rauch, N; Scheu, C; Ruehle, M; Benhassine, M; Seveno, D; de Coninck, J; Lopez-Esteban, S

2007-10-01

The spontaneous spreading of small liquid metal (Cu, Ag, Au) and oxide drops on Mo substrates has been studied using a drop transfer setup combined with high-speed video. Under the experimental conditions used in this work, spreading occurs in the absence of interfacial reactions or ridging. The analysis of the spreading data indicates that dissipation at the triple junction (that can be described in terms of a triple-line friction) is playing a dominant role in the movement of the liquid front. This is due, in part, to the much stronger atomic interactions in high-temperature systems when compared to organic liquids. As a result of this analysis, a comprehensive view of spreading emerges in which the strength of the atomic interactions (solid-liquid, liquid-liquid) determines the relative roles of viscous impedance and dissipation at the triple junction in spreading kinetics.

HYFIRE: a tokamak/high-temperature electrolysis system

International Nuclear Information System (INIS)

Fillo, J.A.; Powell, J.P.; Benenati, R.; Varljen, T.C.; Chi, J.W.H.; Karbowski, J.S.

1981-01-01

The HYFIRE studies to date have investigated a number of technical approaches for using the thermal energy produced in a high-temperature Tokamak blanket to provide the electrical and thermal energy required to drive a high-temperature (> 1000 0 C) water electrolysis process. Current emphasis is on two design points, one consistent with electrolyzer peak inlet temperatures of 1400 0 C, which is an extrapolation of present experience, and one consistent with a peak electrolyzer temperature of 1100 0 C. This latter condition is based on current laboratory experience with high-temperature solid electrolyte fuel cells. Our major conclusion to date is that the technical integration of fusion and high-temperature electrolysis appears to be feasible and that overall hydrogen production efficiencies of 50 to 55% seem possible

Spectral emissivity measurements of candidate materials for very high temperature reactors

Energy Technology Data Exchange (ETDEWEB)

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

2012-10-15

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

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

Borehole Stability in High-Temperature Formations

Science.gov (United States)

Yan, Chuanliang; Deng, Jingen; Yu, Baohua; Li, Wenliang; Chen, Zijian; Hu, Lianbo; Li, Yang

2014-11-01

In oil and gas drilling or geothermal well drilling, the temperature difference between the drilling fluid and formation will lead to an apparent temperature change around the borehole, which will influence the stress state around the borehole and tend to cause borehole instability in high geothermal gradient formations. The thermal effect is usually not considered as a factor in most of the conventional borehole stability models. In this research, in order to solve the borehole instability in high-temperature formations, a calculation model of the temperature field around the borehole during drilling is established. The effects of drilling fluid circulation, drilling fluid density, and mud displacement on the temperature field are analyzed. Besides these effects, the effect of temperature change on the stress around the borehole is analyzed based on thermoelasticity theory. In addition, the relationships between temperature and strength of four types of rocks are respectively established based on experimental results, and thermal expansion coefficients are also tested. On this basis, a borehole stability model is established considering thermal effects and the effect of temperature change on borehole stability is also analyzed. The results show that the fracture pressure and collapse pressure will both increase as the temperature of borehole rises, and vice versa. The fracture pressure is more sensitive to temperature. Temperature has different effects on collapse pressures due to different lithological characters; however, the variation of fracture pressure is unrelated to lithology. The research results can provide a reference for the design of drilling fluid density in high-temperature wells.

Interaction of prechilling, temperature, osmotic stress, and light in Picea abies seed germination

International Nuclear Information System (INIS)

Leinonen, K.; Rita, H.

1995-01-01

A multi-factor experimental approach and proportional odds model was used to study interactions between five environmental factors significant to Norway spruce seed germination: prechilling (at +4.5 °C), suboptimal temperatures (+12 and +16 °C), osmotically induced water stress (–0.3 Mpa and 0 Mpa), prolonged white light, and short-period far-red light. Temperature and osmotic stress interacted with one another in the germination of seeds: the effect of osmotic stress being stronger at +16 °C than at +12 °C. In natural conditions, this interaction may prevent germination early in the summer when soil dries and temperature increases. Prolonged white light prevented germination at low temperature and low osmotic potential. Inhibitory effect was less at higher temperatures and higher osmotic potential, as well as after prechilling. Short-period far-red light did not prevent germination of unchilled seeds in darkness. Prechilling tended to make seeds sensitive to short pulses of far-red light, an effect which depended on temperature: at +12 °C the effect on germination was promotive, but at +16 °C, inhibitory and partly reversible by white light. It seems that Norway spruce seeds may have adapted to germinate in canopy shade light rich in far-red. The seeds may also have evolved mechanisms to inhibit germination in prolonged light

Interactive effect of elevated CO2 and temperature on coral physiology

Science.gov (United States)

Grottoli, A. G.; Cai, W.; Warner, M.; Melman, T.; Schoepf, V.; Baumann, J.; Matsui, Y.; Pettay, D. T.; Hoadley, K.; Xu, H.; Wang, Y.; Li, Q.; Hu, X.

2011-12-01

Increases in ocean acidification and temperature threaten coral reefs globally. However, the interactive effect of both lower pH and higher temperature on coral physiology and growth are poorly understood. Here, we present preliminary findings from a replicated controlled experiment where four species of corals (Acorpora millepora, Pocillopora damicornis, Montipora monasteriata, Turbinaria reniformis) were reared under the following six treatments for three weeks: 1) 400ppm CO2 and ambient temperature, 2) 400ppm CO2 and elevated temperature, 3) 650ppm CO2 and ambient temperature, 4) 650ppm CO2 and elevated temperature, 5) 800ppm CO2 and ambient temperature, 6) 800ppm CO2 and elevated temperature. Initial findings of photophysiological health (Fv/Fm), calcification rates (as measured by both buoyant weight and the total alkalinity methods), and energy reserves will be presented.

Ion filter for high temperature cleaning

International Nuclear Information System (INIS)

Kutomi, Yasuhiro; Nakamori, Masaharu.

1994-01-01

A porous ceramic pipe mainly comprising alumina is used as a base pipe, and then crud and radioactive ion adsorbing materials in high temperature and high pressure water mainly comprising a FeTiO 3 compound are flame-coated on the outer surface thereof to a film thickness of about 100 to 300μ m as an aimed value by an acetylene flame-coating method. The flame-coated FeTiO 3 layer is also porous, so that high temperature and high pressure water to be cleaned can pass through from the inside to the outside of the pipe. Cruds can be removed and radioactive ions can be adsorbed during passage. Since all the operations can be conducted at high temperature and high pressure state, cooling is no more necessary for the high temperature and high pressure water to be cleaned, heat efficiency of the plant can be improved and a cooling facility can be saved. Further, since the flame-coating of FeTiO 3 to the porous ceramic pipe can be conducted extremely easily compared with production of a sintering product, cost for the production of filter elements can be saved remarkably. (T.M.)

High temperature fusion reactor design

International Nuclear Information System (INIS)

Harkness, S.D.; dePaz, J.F.; Gohar, M.Y.; Stevens, H.C.

1979-01-01

Fusion energy may have unique advantages over other systems as a source for high temperature process heat. A conceptual design of a blanket for a 7 m tokamak reactor has been developed that is capable of producing 1100 0 C process heat at a pressure of approximately 10 atmospheres. The design is based on the use of a falling bed of MgO spheres as the high temperature heat transfer system. By preheating the spheres with energy taken from the low temperature tritium breeding part of the blanket, 1086 MW of energy can be generated at 1100 0 C from a system that produces 3000 MW of total energy while sustaining a tritium breeding ratio of 1.07. The tritium breeding is accomplished using Li 2 O modules both in front of (6 cm thick) and behind (50 cm thick) the high temperature ducts. Steam is used as the first wall and front tritium breeding module coolant while helium is used in the rear tritium breeding region. The system produces 600 MW of net electricity for use on the grid

High power densities from high-temperature material interactions. [in thermionic energy conversion and metallic fluid heat pipes

Science.gov (United States)

Morris, J. F.

1981-01-01

Thermionic energy conversion (TEC) and metallic-fluid heat pipes (MFHPs), offering unique advantages in terrestrial and space energy processing by virtue of operating on working-fluid vaporization/condensation cycles that accept great thermal power densities at high temperatures, share complex materials problems. Simplified equations are presented that verify and solve such problems, suggesting the possibility of cost-effective applications in the near term for TEC and MFHP devices. Among the problems discussed are: the limitation of alkali-metal corrosion, protection against hot external gases, external and internal vaporization, interfacial reactions and diffusion, expansion coefficient matching, and creep deformation.

High temperature divertor plasma operation

International Nuclear Information System (INIS)

Ohyabu, Nobuyoshi.

1991-02-01

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

High Temperature Operational Experiences of Helium Experimental Loop

International Nuclear Information System (INIS)

Kim, Chan Soo; Hong, Sung-Deok; Kim, Eung-Seon; Kim, Min Hwan

2015-01-01

The development of high temperature components of VHTR is very important because of its higher operation temperature than that of a common light water reactor and high pressure industrial process. The development of high temperature components requires the large helium loop. Many countries have high temperature helium loops or a plan for its construction. Table 1 shows various international state-of-the-art of high temperature and high pressure gas loops. HELP performance test results show that there is no problem in operation of HELP at the very high temperature experimental condition. These experimental results also provide the basic information for very high temperature operation with bench-scale intermediate heat exchanger prototype in HELP. In the future, various heat exchanger tests will give us the experimental data for GAMMA+ validation about transient T/H behavior of the IHX prototype and the optimization of the working fluid in the intermediate loop

High-pressure high-temperature phase diagram of organic crystal paracetamol

Science.gov (United States)

Smith, Spencer J.; Montgomery, Jeffrey M.; Vohra, Yogesh K.

2016-01-01

High-pressure high-temperature (HPHT) Raman spectroscopy studies have been performed on the organic crystal paracetamol in a diamond anvil cell utilizing boron-doped heating diamond anvil. Isobaric measurements were conducted at pressures up to 8.5 GPa and temperature up to 520 K in five different experiments. Solid state phase transitions from monoclinic Form I  →  orthorhombic Form II were observed at various pressures and temperatures as well as transitions from Form II  →  unknown Form IV. The melting temperature for paracetamol was observed to increase with increasing pressures to 8.5 GPa. This new data is combined with previous ambient temperature high-pressure Raman and x-ray diffraction data to create the first HPHT phase diagram of paracetamol.

High-pressure high-temperature phase diagram of organic crystal paracetamol

International Nuclear Information System (INIS)

Smith, Spencer J; Montgomery, Jeffrey M; Vohra, Yogesh K

2016-01-01

High-pressure high-temperature (HPHT) Raman spectroscopy studies have been performed on the organic crystal paracetamol in a diamond anvil cell utilizing boron-doped heating diamond anvil. Isobaric measurements were conducted at pressures up to 8.5 GPa and temperature up to 520 K in five different experiments. Solid state phase transitions from monoclinic Form I  →  orthorhombic Form II were observed at various pressures and temperatures as well as transitions from Form II  →  unknown Form IV. The melting temperature for paracetamol was observed to increase with increasing pressures to 8.5 GPa. This new data is combined with previous ambient temperature high-pressure Raman and x-ray diffraction data to create the first HPHT phase diagram of paracetamol. (paper)

"Green" High-Temperature Polymers

Science.gov (United States)

Meador, Michael A.

1998-01-01

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

High temperature alloys and ceramic heat exchanger

International Nuclear Information System (INIS)

Okamoto, Masaharu

1984-04-01

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

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

Finding high-temperature superconductors by metallizing the σ-bonding electrons

International Nuclear Information System (INIS)

Gao Miao; Lu Zhongyi; Xiang Tao

2015-01-01

Raising superconducting transition temperature (T_c) is an important task of fundamental research on superconductivity. It is also a prerequisite for the large scale application of superconductors. Since the microscopic mechanism of high-T_c superconductivity is unknown, the conventional approach for increasing T_c is either to apply high pressure to a material which has the potential to become superconducting, or to push it close to an antiferromagnetic or some other quantum instability point by chemical doping. In this article, the authors point out that another general approach for raising T_c is to lift the σ-bonding bands to the Fermi level, or to metallize the σ-bonding elections. This approach can increase the probability of finding a novel high-T_c superconductor because the coupling of σ-bonding electrons with phonons is generally strong and the superconducting transition induced by this interaction can occur at relatively high temperatures. After elucidating the underlying mechanism, the authors discuss a number of schemes to metallize σ-bonding electrons, and present their recent prediction for the crystalline and electronic structures of two potential high-T_c superconductors, Li_2B_3C and Li_3B_4C_2, with T_c higher than 50 K. (authors)

Distributed Temperature Sensing - a Useful Tool for Investigation of Surface Water - Groundwater Interaction

Science.gov (United States)

Vogt, T.; Hahn-Woernle, L.; Sunarjo, B.; Thum, T.; Schneider, P.; Schirmer, M.; Cirpka, O. A.

2009-04-01

In recent years, the transition zone between surface water bodies and groundwater, known as the hyporheic zone, has been identified as crucial for the ecological status of the open-water body and the quality of groundwater. The hyporheic exchange processes vary both in time and space. For the assessment of water quality of both water bodies reliable models and measurements of the exchange rates and their variability are needed. A wide range of methods and technologies exist to estimate water fluxes between surface water and groundwater. Due to recent developments in sensor techniques and data logging work on heat as a tracer in hydrological systems advances, especially with focus on surface water - groundwater interactions. Here, we evaluate the use of Distributed Temperature Sensing (DTS) for the qualitative and quantitative investigation of groundwater discharge into and groundwater recharge from a river. DTS is based on the temperature dependence of Raman scattering. Light from a laser pulse is scattered along an optical fiber of up to several km length, which is the sensor of the DTS system. By sampling the the back-scattered light with high temporal resolution, the temperature along the fiber can be measured with high accuracy (0.1 K) and high spatial resolution (1 m). We used DTS at a test side at River Thur in North-East Switzerland. Here, the river is loosing and the aquifer is drained by two side-channels, enabling us to test DTS for both, groundwater recharge from the river and groundwater discharge into the side-channels. For estimation of seepage rates, we measured highly resolved vertical temperature profiles in the river bed. For this application, we wrapped an optical fiber around a piezometer tube and measured the temperature distribution along the fiber. Due to the wrapping, we obtained a vertical resolution of approximately 5 mm. We analyzed the temperature time series by means of Dynamic Harmonic Regression as presented by Keery et al. (2007

Development of VHTR high temperature piping in KHI

International Nuclear Information System (INIS)

Suzuki, Nobuhiro; Takano, Shiro

1981-01-01

The high temperature pipings used for multi-purpose high temperature gas-cooled reactors are the internally insulated pipings for transporting high temperature, high pressure helium at 1000 deg C and 40 kgf/cm 2 , and the influences exerted by their performance as well as safety to the plants are very large. Kawasaki Heavy Industries, Ltd., has engaged in the development of the high temperature pipings for VHTRs for years. In this report, the progress of the development, the test carried out recently and the problems for future are described. KHI manufactured and is constructing a heater and internally insulated helium pipings for the large, high temperature structure testing loop constructed by Japan Atomic Energy Research Institute. The design concept for the high temperature pipings is to separate the temperature boundary and the pressure boundary, therefore, the double walled construction with internal heat insulation was adopted. The requirements for the high temperature pipings are to prevent natural convection, to prevent bypass flow, to minimize radiation heat transfer and to reduce heat leak through insulator supporters. The heat insulator is composed of two layers, metal laminate insulator and fiber insulator of alumina-silica. The present state of development of the high temperature pipings for VHTRs is reported. (Kako, I.)

Predictions for impurity-induced Tc suppression in the high-temperature superconductors

International Nuclear Information System (INIS)

Radtke, R.J.; Levin, K.; Schuettler, H.; Norman, M.R.

1993-01-01

We address the question of whether anisotropic superconductivity is compatible with the evidently weak sensitivity of the critical temperature T c to sample quality in the high-T c copper oxides. We examine this issue quantitatively by solving the strong-coupling Eliashberg equations numerically as well as analytically for s-wave impurity scattering within the second Born approximation. For pairing interactions with a characteristically low energy scale, we find an approximately universal dependence of the d-wave superconducting transition temperature on the planar residual resistivity which is independent of the details of the microscopic pairing. These results, in conjunction with future systematic experiments, should help elucidate the symmetry of the order parameter in the cuprates

Mechanism of high-temperature resistant water-base mud

Energy Technology Data Exchange (ETDEWEB)

Luo, P

1981-01-01

Based on experiments, the causes and laws governing the changes in the performance of water-base mud under high temperature are analyzed, and the requisites and mechanism of treating agents resisting high temperature are discussed. Ways and means are sought for inhibiting, delaying and making use of the effect of high temperature on the performance of mud, while new ideas and systematic views have been expressed on the preparation of treating agents and set-up of a high temperature resistant water-base mud system. High temperature dispersion and high temperature surface inactivation of clay in the mud, as well as their effect and method of utilization are reviewed. Subjects also touched upon include degradation and cross-linking of the high-temperature resistant treating agents, their use and effect. Based on the above, the preparation of a water-base and system capable of resisting 180 to 250/sup 0/C is recommended.

Temperature dependence of the Rashba and Dresselhaus spin–orbit interactions in GaAs wells

International Nuclear Information System (INIS)

Wang, W.; Fu, J.Y.

2016-01-01

We have recently shown [Fu and Egues, Phys. Rev. B 91 (2015) 075408] unusual properties of the spin–orbit (SO) interaction in relatively wide quantum wells, e.g., the second subband Rashba term can vanish even in asymmetric configurations. Here we report our theoretical investigation on the temperature dependence of Rashba and Dresselhaus SO interactions in GaAs both relatively narrow and wide wells, having the electron occupancy of one and two subbands, respectively. We consider all relevant intra- and intersubband SO terms. We find that the variation of intrasubband couplings as temperatures range from 0.3 to 300 K could attain, ∼meV Å, the order of usual magnitudes for SO terms in GaAs wells. Moreover, we observe distinct behaviors of the SO interaction of the two subbands, as functions of temperature. On the other band, we find that the intersubband SO terms have a relatively weak temperature dependence.

Temperature dependence of the Rashba and Dresselhaus spin–orbit interactions in GaAs wells

Energy Technology Data Exchange (ETDEWEB)

Wang, W. [Department of Physics, Jining University, 273155 Qufu, Shandong (China); Fu, J.Y., E-mail: jiyongfu78@gmail.com [Department of Physics, Qufu Normal University, 273165 Qufu, Shandong (China); Instituto de Física de São Carlos, Universidade de São Paulo, 13560-970 São Carlos, SP (Brazil); Departamento de Física, Universidade Federal de São Carlos, 13565-905 São Carlos, SP (Brazil)

2016-02-01

We have recently shown [Fu and Egues, Phys. Rev. B 91 (2015) 075408] unusual properties of the spin–orbit (SO) interaction in relatively wide quantum wells, e.g., the second subband Rashba term can vanish even in asymmetric configurations. Here we report our theoretical investigation on the temperature dependence of Rashba and Dresselhaus SO interactions in GaAs both relatively narrow and wide wells, having the electron occupancy of one and two subbands, respectively. We consider all relevant intra- and intersubband SO terms. We find that the variation of intrasubband couplings as temperatures range from 0.3 to 300 K could attain, ∼meV Å, the order of usual magnitudes for SO terms in GaAs wells. Moreover, we observe distinct behaviors of the SO interaction of the two subbands, as functions of temperature. On the other band, we find that the intersubband SO terms have a relatively weak temperature dependence.

Interactive short-term effects of equivalent temperature and air pollution on human mortality in Berlin and Lisbon.

Science.gov (United States)

Burkart, Katrin; Canário, Paulo; Breitner, Susanne; Schneider, Alexandra; Scherber, Katharina; Andrade, Henrique; Alcoforado, Maria João; Endlicher, Wilfried

2013-12-01

There is substantial evidence that both temperature and air pollution are predictors of mortality. Thus far, few studies have focused on the potential interactive effects between the thermal environment and different measures of air pollution. Such interactions, however, are biologically plausible, as (extreme) temperature or increased air pollution might make individuals more susceptible to the effects of each respective predictor. This study investigated the interactive effects between equivalent temperature and air pollution (ozone and particulate matter) in Berlin (Germany) and Lisbon (Portugal) using different types of Poisson regression models. The findings suggest that interactive effects exist between air pollutants and equivalent temperature. Bivariate response surface models and generalised additive models (GAMs) including interaction terms showed an increased risk of mortality during periods of elevated equivalent temperatures and air pollution. Cold effects were mostly unaffected by air pollution. The study underscores the importance of air pollution control in mitigating heat effects. Copyright © 2013 Elsevier Ltd. All rights reserved.

CDSD-4000: High-resolution, high-temperature carbon dioxide spectroscopic databank

International Nuclear Information System (INIS)

Tashkun, S.A.; Perevalov, V.I.

2011-01-01

We present a high-resolution, high-temperature version of the Carbon Dioxide Spectroscopic Databank called CDSD-4000. The databank contains the line parameters (positions, intensities, air- and self-broadened half-widths, coefficients of temperature dependence of air- and self-broadened half-widths, and air-broadened pressure shifts) of the four most abundant isotopologues of CO 2 . A reference temperature is 296 K and an intensity cutoff is 10 -27 cm -1 /molecule cm -2 at 4000 K. The databank has 628,324,454 entries, covers the 226-8310 cm -1 spectral range and designed for the temperature range 2500-5000 K. Format of CDSD-4000 is similar to that of HITRAN-2008. The databank has been generated within the framework of the method of effective operators and based on the global fittings of spectroscopic parameters (parameters of the effective Hamiltonians and effective dipole moment operators) to observed data collected from the literature. The databank is useful for studying high-temperature radiative properties of CO 2 , including exoplanets atmospheres, aerothemal modeling for Mars entry missions, high-temperature laboratory spectra, and industrial applications. CDSD-4000 is freely accessible via the Internet site (ftp://ftp.iao.ru/pub/CDSD-4000).

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.

High-temperature superconducting conductors and cables

International Nuclear Information System (INIS)

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

1996-01-01

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

High-light damage in air-dry thalli of the old forest lichen Lobaria pulmonaria - interactions of irradiance, exposure duration and high temperature

International Nuclear Information System (INIS)

Gauslaa, Y.; Solhaug, K.A.

1999-01-01

High-light damage in air-dry thalli of Lobaria pulmonaria were measured in the laboratory as reductions in maximal PSII efficiency (FV/FM) after a 48 h recovery in a hydrated state at low light to account for permanent damage. Thalli treated with the lowest light dose (90 mol photons m −2 ) recovered normal FV/FM-values with increasing irradiances (400–700 nm) up to 1000 µmol photons m −2 s −1 . Doubling this dose lowered the threshold level for damage from 1000 to 320 µmol photons m −2 s −1 , and reduced FV/FM at 1000 µmol photons m −2 s −1 by more than 50%. A second doubling of the dose to 360 mol photons m −2 caused damage at 200 µmol photons m −2 s −1 , and a nearly complete cessation of PSII efficiency occurred at 1000 µmol photons m −2 s −1 . No reciprocity of irradiance and duration of illumination for PSII function was found. The measured time-dependent decrease in FV/FM was remarkably similar for the naturally coupled, but artificially separated, light and temperature factors. Therefore, the damage of high light on desiccated L. pulmonaria seemed to be an additive effect of high irradiance and high temperatures. Air-dry thalli were highly heat susceptible, being affected already at temperatures around 40 °C. Logging operations in forests are likely to raise the solar radiation at remaining lichen sites to destructive levels. (author)

Expanding Upon the MEMS Framework: How Temperature Impacts Organo-Mineral Interactions

Science.gov (United States)

Smith, K.; Waring, B. G.

2017-12-01

Microbial substrate use efficiency (SUE; the fraction of substrate carbon (C) incorporated into biomass vs. respired) affects the development of soil organic matter (SOM). An emerging theoretical model (the Microbial Efficiency-Matrix Stabilization (MEMS) framework) posits that microbial SUE acts as a filter for plant litter inputs, whereby a larger proportion of microbial products are synthesized from labile (and not recalcitrant) plant substrates. Thus, SOM stability depends on both the efficiency of microbial anabolism as well as the degree to which microbial products stabilize within the mineral soil matrix. In this study, we performed a laboratory microcosm experiment using diverse soils collected in Utah to test how substrate complexity, soil mineralogy, and temperature interact to control SOM formation. Prior to microcosm setup, we first removed organic C from our field soils by washing with concentrated hypochlorite solution. Microcosms were then assembled by mixing C-free soil with one of three substrates (glucose, cellulose, and lignin), and placed in incubators set to different temperatures (18°, 28°, and 38°C). Respiration rates were then estimated by periodically sampling headspace CO2 concentrations in each microcosm. Prior to C removal, we found that field soils exhibited distinct properties ranging from clay-rich vertisols (55:27:18, sand:silt:clay; 1.1% C), to loamy-sand entisols (85:11:4; 0.3% C), and organic-rich mollisols (79:17:4; 1.7% C). In the incubation experiment, consistent with enzyme kinetics theory, respiration rates increased as a function of incubation temperature (p soil effects (including interactions with temperature and substrate) were less clear. Together these results build upon the MEMS framework by highlighting the importance of organo-mineral interactions and temperature as controls on soil C cycling.

Technology development for high temperature logging tools

Energy Technology Data Exchange (ETDEWEB)

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

1979-01-01

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

Andreev spectrum with high spin-orbit interactions: Revealing spin splitting and topologically protected crossings

Science.gov (United States)

Murani, A.; Chepelianskii, A.; Guéron, S.; Bouchiat, H.

2017-10-01

In order to point out experimentally accessible signatures of spin-orbit interaction, we investigate numerically the Andreev spectrum of a multichannel mesoscopic quantum wire (N) with high spin-orbit interaction coupled to superconducting electrodes (S), contrasting topological and nontopological behaviors. In the nontopological case (square lattice with Rashba interactions), we find that the Kramers degeneracy of Andreev levels is lifted by a phase difference between the S reservoirs except at multiples of π , when the normal quantum wires can host several conduction channels. The level crossings at these points invariant by time-reversal symmetry are not lifted by disorder. Whereas the dc Josephson current is insensitive to these level crossings, the high-frequency admittance (susceptibility) at finite temperature reveals these level crossings and the lifting of their degeneracy at π by a small Zeeman field. We have also investigated the hexagonal lattice with intrinsic spin-orbit interaction in the range of parameters where it is a two-dimensional topological insulator with one-dimensional helical edges protected against disorder. Nontopological superconducting contacts can induce topological superconductivity in this system characterized by zero-energy level crossing of Andreev levels. Both Josephson current and finite-frequency admittance carry then very specific signatures at low temperature of this disorder-protected Andreev level crossing at π and zero energy.

High-temperature reaction of ''anisotropic'' pyrolitic graphite with oxygen

International Nuclear Information System (INIS)

Lavrenko, V.A.; Pomytkin, A.P.; Neshpor, V.S.; Vinokur, F.L.

1980-01-01

Investigated is the kinetics of initial interaction stages of highly dense crystalloorientated pyrographite with oxygen. Oxidation was carried out in pure oxygen within 0.1-740 mm Hg pressure range and 500-1100 deg C temperature range. It is stated, that at the temperatures below 700 deg C pyrographite oxidation is subjected to a linear law. Above 700-800 deg C the linear law is preserved only at the initial oxidation stage, then the process is described by a parabolic law. Extension of the linear site is decreased in time with the reduction of oxygen pressure. The reaction has apparent fractional order. Activation energy of pyrogrpahite oxidation by the linear low constitutes approximately 58 kcal/mol within 600-800 deg C range and 14 kcal/mol within 800-1100 deg C range. The apparent activation energy constitutes approximately 13 kcal/mol in the region of correspondence to the parabolic law

INTERACTION BETWEEN THE ADH AND ALPHA-GPDH LOCI IN DROSOPHILA-MELANOGASTER - ADULT SURVIVAL AT HIGH-TEMPERATURE

NARCIS (Netherlands)

OUDMAN, L; VANDELDEN, W; KAMPING, A; BIJLSMA, R

The role of high temperature resistance in the world-wide cline of Adh and alpha-Gpdh allele frequencies of Drosophila melanogaster was investigated. Experimental strains were used with different combinations of Adh and alpha-Gpdh alleles but with similar genetic background. The survival time of

Stiff self-interacting strings at high temperature QCD

Directory of Open Access Journals (Sweden)

S Bakry A.

2018-01-01

Full Text Available We investigate the implications of Nambu-Goto (NG, Lüscher Weisz (LW and Polyakov-Kleinert (PK effective string actions for the Casimir energy and the width of the quantum delocalization of the string in 4-dim pure SU(3 Yang-Mills lattice gauge theory. At a temperature closer to the critical point T/Tc=0.9, we found that the next to leading-order (NLO contributions from the expansion of the NG string in addition to the boundary terms in LW action to decrease the deviations from the lattice data in the intermediate distance scales for both the quark-antiquark QQ̅ potential and broadening of the color tube compared to the free string approximation. We conjecture possible stiffness of the QCD string through studying the effects of extrinsic curvature term in PK action and find a good fitting behavior for the lattice Monte-Carlo data at both long and intermediate quark separations regions.

Stiff self-interacting strings at high temperature QCD

Science.gov (United States)

S Bakry, A.; Chen, X.; Deliyergiyev, M.; Galal, A.; Khalaf, A.; M Pengming, P.

2018-03-01

We investigate the implications of Nambu-Goto (NG), Lüscher Weisz (LW) and Polyakov-Kleinert (PK) effective string actions for the Casimir energy and the width of the quantum delocalization of the string in 4-dim pure SU(3) Yang-Mills lattice gauge theory. At a temperature closer to the critical point T/Tc=0.9, we found that the next to leading-order (NLO) contributions from the expansion of the NG string in addition to the boundary terms in LW action to decrease the deviations from the lattice data in the intermediate distance scales for both the quark-antiquark QQ̅ potential and broadening of the color tube compared to the free string approximation. We conjecture possible stiffness of the QCD string through studying the effects of extrinsic curvature term in PK action and find a good fitting behavior for the lattice Monte-Carlo data at both long and intermediate quark separations regions.

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.

High Temperature Electrolysis

DEFF Research Database (Denmark)

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

2015-01-01

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

High temperature mechanical properties of iron aluminides

International Nuclear Information System (INIS)

Morris, D. G.; Munoz-Morris, M. A.

2001-01-01

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 materials, 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. (Author)

Contribution to high-temperature chromatography and high-temperature-gas-chromatography-mass spectrometry of lipids

International Nuclear Information System (INIS)

Aichholz, R.

1998-04-01

This thesis describes the use of high temperature gas chromatography for the investigation of unusual triacylglycerols, cyanolipids and bees waxes. The used glass capillary columns were pretreated and coated with tailor made synthesized high temperature stable polysiloxane phases. The selective separation properties of the individual columns were tested with a synthetic lipid mixture. Suitable derivatization procedures for the gaschromatographic analyses of neutral lipids, containing multiple bonds as well as hydroxy-, epoxy-, and carboxyl groups, were developed and optimized. Therefore conjugated olefinic-, conjugated olefinic-acetylenic-, hydroxy-, epoxy-, and conjugated olefinic keto triacylglycerols in miscellaneous plant seed oils as well as hydroxy monoesters, diesters and hydroxy diesters in bees waxes could be analysed directly with high temperature gas chromatography for the first time. In order to elucidate the structures of separated lipid compounds, high temperature gas chromatography was coupled to mass spectrometry and tandem mass spectrometry, respectively. Comparable analytical systems are hitherto not commercial available. Therefore instrumental prerequisites for a comprehensive and detailed analysis of seed oils and bees waxes were established. In GC/MS commonly two ionization methods are used, electron impact ionization and chemical ionization. For the analysis of lipids the first is of limited use only. Due to intensive fragmentation only weak molecular ions are observed. In contrast, the chemical ionization yields in better results. Dominant quasi molecular ions enable an unambiguous determination of the molecular weight. Moreover, characteristic fragment ions provide important indications of certain structural features of the examined compounds. Nevertheless, in some cases the chromatographic resolution was insufficient in order to separate all compounds present in natural lipid mixtures. Owing to the selected detection with mass spectrometry

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

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.

Temperature dependence of the phonon structure in the high-temperature superconductor Bi2Sr2CaCu2O8 studied by infrared reflectance spectroscopy

International Nuclear Information System (INIS)

Kamaras, K.; Herr, S.L.; Porter, C.D.; Tanner, D.B.; Etemad, S.; Tarascon, J.

1991-01-01

We have investigated a ceramic sample of the high-temperature superconductor Bi 2 Sr 2 CaCu 2 O 8 (T c =85 K) by infrared and visible reflectance spectroscopy at several temperatures both below and above the superconducting transition. We find that the temperature variation in the vibrational region is associated with minima or antiresonance features of the optical conductivity, instead of maxima, indicating strong Fano-type electron-phonon interaction and implying that the phonon structure in the infrared is strongly affected by the ab-plane response

Deformation of high-temperature superconductors

International Nuclear Information System (INIS)

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

1994-08-01

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

NSTX High Temperature Sensor Systems

International Nuclear Information System (INIS)

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

1999-01-01

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

Transition temperature to the superconducting phase of QCD at high baryon density

International Nuclear Information System (INIS)

Brown, William E.; Liu, James T.; Ren, Hai-cang

2000-01-01

Recent interest in the study of color superconductivity has focused on the regime of high baryon density where perturbative QCD may be employed. Based on the dominant one-gluon-exchange interaction, both the transition temperature and zero temperature gap have been determined to leading order in the coupling g. While the leading non-BCS behavior T C ∼μg -5 e -κ/g is easily obtained, the pre-exponential factor has proved more difficult to evaluate. Focusing on the transition temperature, we present a perturbative derivation of this factor, exact to leading order in g. This approach is first motivated by the study of a toy model and involves working to second order in the perturbative expansion. We compare this result to the zero temperature gap. Additionally, we extend the analysis to the case of higher angular momentum for longitudinal and transverse quark pairing. (c) 2000 The American Physical Society

On high temperature strength of carbon steels

International Nuclear Information System (INIS)

Ichinose, Hiroyuki; Tamura, Manabu; Kanero, Takahiro; Ihara, Yoshihito

1977-01-01

In the steels for high temperature use, the oxidation resistance is regarded as important, but carbon steels show enough oxidation resistance to be used continuously at the temperature up to 500 deg. C if the strength is left out of consideration, and up to 450 deg. C even when the strength is taken into account. Moreover, the production is easy, the workability and weldability are good, and the price is cheap in carbon steels as compared with alloy steels. In the boilers for large thermal power stations, 0.15-0.30% C steels are used for reheater tubes, main feed water tubes, steam headers, wall water tubes, economizer tubes, bypass pipings and others, and they account for 70% of all steel materials used for the boilers of 350 MW class and 30% in 1000 MW class. The JIS standard for the carbon steels for high temperature use and the related standards in foreign countries are shown. The high temperature strength of carbon steels changes according to the trace elements, melting and heat treatment as well as the main compositions of C, Si and Mn. Al and N affect the high temperature strength largely. The characteristics of carbon steels after the heating for hours, the factors controlling the microstructure and high temperature strength, and the measures to improve the high temperature strength of carbon steels are explained. (Kako, I.)

Nuclear fuels for very high temperature applications

International Nuclear Information System (INIS)

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

1992-01-01

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

Close-Spaced High Temperature Knudsen Flow.

Science.gov (United States)

1986-07-15

radiant heat source assembly was substituted for the brazed molybdenum one in order to achieve higher radiant heater temperatures . 2.1.4 Experimental...at very high temperature , and ground flat. The molybdenum is then chemically etched to the desired depth using an etchant which does not affect...RiB6 295 -CLSE PCED HIGH TEMPERATURE KNUDSEN FLOU(U) RASOR I AiASSOCIATES INC SUNNYVALE CA J 8 MCVEY 15 JUL 86 NSR-224 AFOSR-TR-87-1258 F49628-83-C

Development of High Temperature/High Sensitivity Novel Chemical Resistive Sensor

Energy Technology Data Exchange (ETDEWEB)

Ma, Chunrui [Univ. of Texas, San Antonio, TX (United States); Enriquez, Erik [Univ. of Texas, San Antonio, TX (United States); Wang, Haibing [Univ. of Texas, San Antonio, TX (United States); Xu, Xing [Univ. of Texas, San Antonio, TX (United States); Bao, Shangyong [Univ. of Texas, San Antonio, TX (United States); Collins, Gregory [Univ. of Texas, San Antonio, TX (United States)

2013-08-13

The research has been focused to design, fabricate, and develop high temperature/high sensitivity novel multifunctional chemical sensors for the selective detection of fossil energy gases used in power and fuel systems. By systematically studying the physical properties of the LnBaCo₂O_5+d (LBCO) [Ln=Pr or La] thin-films, a new concept chemical sensor based high temperature chemical resistant change has been developed for the application for the next generation highly efficient and near zero emission power generation technologies. We also discovered that the superfast chemical dynamic behavior and an ultrafast surface exchange kinetics in the highly epitaxial LBCO thin films. Furthermore, our research indicates that hydrogen can superfast diffuse in the ordered oxygen vacancy structures in the highly epitaxial LBCO thin films, which suggest that the LBCO thin film not only can be an excellent candidate for the fabrication of high temperature ultra sensitive chemical sensors and control systems for power and fuel monitoring systems, but also can be an excellent candidate for the low temperature solid oxide fuel cell anode and cathode materials.

Proceedings of damage and oxidation protection in high temperature composites

International Nuclear Information System (INIS)

Haritos, G.K.; Ochoa, O.O.

1991-01-01

This book contains proceedings of Damage and Oxidation Protection in High Temperature Composites. Topics covered include: current issues in the development of new materials and structural concepts for the aerospace structures of the future; transportation vehicles of the future; materials and structural concepts; fundamental understanding and quantitative descriptions of the physical processes and mechanisms controlling the behavior of emerging materials and structures; and the critical need for advances in our understanding of how the interaction of service loads and environment influences the lifecycle of emerging structures and materials

High temperature and high pressure equation of state of gold

International Nuclear Information System (INIS)

Matsui, Masanori

2010-01-01

High-temperature and high-pressure equation of state (EOS) of Au has been developed using measured data from shock compression up to 240 GPa, volume thermal expansion between 100 and 1300 K and 0 GPa, and temperature dependence of bulk modulus at 0 GPa from ultrasonic measurements. The lattice thermal pressures at high temperatures have been estimated based on the Mie-Grueneisen-Debye type treatment with the Vinet isothermal EOS. The contribution of electronic thermal pressure at high temperatures, which is relatively insignificant for Au, has also been included here. The optimized EOS parameters are K' 0T = 6.0 and q = 1.6 with fixed K 0T = 167 GPa, γ 0 = 2.97, and Θ 0 = 170 K from previous investigations. We propose the present EOS to be used as a reliable pressure standard for static experiments up to 3000K and 300 GPa.

1981 Annual status report. High-temperature materials

International Nuclear Information System (INIS)

1981-01-01

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

1982 Annual status report: high-temperature materials

International Nuclear Information System (INIS)

Van de Voorde, M.

1983-01-01

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

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

High pressure study of high-temperature superconductors

International Nuclear Information System (INIS)

Souliou, Sofia-Michaela

2014-01-01

The current thesis studies experimentally the effect of high external pressure on high-T c superconductors. The structure and lattice dynamics of several members of the high-T 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 c superconductor YBa 2 Cu 3 O 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 2 Cu 3 O 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 2 Cu 4 O 8 . A clear renormalization of some of the Raman phonons is seen below T 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 1g -like buckling phonon mode. The amplitude of this renormalization strongly increases with pressure, resembling the effect of hole doping in YBa 2 Cu 3 O 6+x . At ∝ 10 GPa, the system undergoes a reversible pressure-induced structural phase transition to a non-centrosymmmetric structure (space group Imm2). The structural transition is clearly reflected in the high pressure

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...

Interactive effects of food quality, temperature and rearing time on condition of juvenile black bream Acanthopagrus butcheri.

Science.gov (United States)

Walther, B D; Elsdon, T S; Gillanders, B M

2010-06-01

A laboratory experiment was conducted to determine the interactive effects of temperature and diet on condition indices of juvenile black bream Acanthopagrus butcheri, reared for time periods ranging from 2 to 42 days. After fish were reared for varying periods, growth, morphometric (Fulton's K) and biochemical [RNA:DNA (R:D) ratios] indices were measured. Fulton's K responded primarily to temperature, with progressive decrease in condition over time for fish reared at high temperatures. In contrast, R:D ratios were primarily affected by diet composition, with the highest values observed for fish reared on fish-based diets as opposed to vegetable-based diets. Significant effects of rearing time were also observed for Fulton's K and R:D ratios, as were some interactive treatment effects. In addition, Fulton's K and R:D ratios were not significantly correlated, perhaps due to the different periods of time integrated by each index or their relative sensitivity to lipid and protein deposition. These results highlight the complex responses of these condition indices to environmental variables and nutritional status.

High-temperature flaw assessment procedure

International Nuclear Information System (INIS)

Ruggles, M.B.; Takahashi, Y.; Ainsworth, R.A.

1989-08-01

The current program represents a joint effort between the Electric Power Research Institute (EPRI) in the USA, the Central Research Institute of Electric Power Industry (CRIEPI) in Japan, and the Central Electricity Generating Board (CEGB) in the UK. The goal is to develop an interim high-temperature flaw assessment procedure for high-temperature reactor components. This is to be accomplished through exploratory experimental and analytical studies of high-temperature crack growth. The state-of-the-art assessment and the fracture mechanics database for both types 304 and 316 stainless steels, completed in 1988, serve as a foundation for the present work. Work in the three participating organizations is progressing roughly on schedule. Results to-date are presented in this document. Fundamental tests results are discussed in Section 2. Section 3 focuses on results of exploratory subcritical crack growth tests. Progress in subcritical crack growth modeling is reported in Section 4. Exploratory failure tests are outlined in Section 5. 21 refs., 70 figs., 7 tabs

Interaction of intense femtosecond laser pulses with high-Z solids

International Nuclear Information System (INIS)

Zhidkov, A.; Sasaki, Akira; Utsumi, Takayuki; Fukumoto, Ichirou; Tajima, Toshiki; Yoshida, Masatake; Kondo, Kenichi

2000-01-01

A plasma irradiated by an intense very short pulse laser can be an ultimate high brightness source of incoherent inner-shell X-ray emission of 1-30 keV. The recently developed 100 TW, 20 fs laser facility in JAERI can make considerable enhancement here. To show this a hybrid model combining hydrodynamics and collisional particle-in-cell simulations is applied. Effect of laser prepulse on the interaction of an intense s-polarized femtosecond, ∼20/40 fs, laser pulse with high-Z solid targets is studied. A new absorption mechanism originating from the interaction of the laser pulse with plasma waves excited by the relativistic component of the Lorentz force is found to increase the absorption rate over 30% even for a very short laser pulse. The obtained hot electron temperature exceeds 0.5-1 MeV at optimal conditions for absorption. Results of the simulation for lower laser pulse intensities are in good agreement with the experimental measurements of the hot electron energy distribution. (author)

High-temperature ductility of electro-deposited nickel

Science.gov (United States)

Dini, J. W.; Johnson, H. R.

1977-01-01

Work done during the past several months on high temperature ductility of electrodeposited nickel is summarized. Data are presented which show that earlier measurements made at NASA-Langley erred on the low side, that strain rate has a marked influence on high temperature ductility, and that codeposition of a small amount of manganese helps to improve high temperature ductility. Influences of a number of other factors on nickel properties were also investigated. They included plating solution temperature, current density, agitation, and elimination of the wetting agent from the plating solution. Repair of a large nozzle section by nickel plating is described.

High temperature materials characterization

Science.gov (United States)

Workman, Gary L.

1990-01-01

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

The High Temperature Tensile and Creep Behaviors of High Entropy Superalloy.

Science.gov (United States)

Tsao, Te-Kang; Yeh, An-Chou; Kuo, Chen-Ming; Kakehi, Koji; Murakami, Hideyuki; Yeh, Jien-Wei; Jian, Sheng-Rui

2017-10-04

This article presents the high temperature tensile and creep behaviors of a novel high entropy alloy (HEA). The microstructure of this HEA resembles that of advanced superalloys with a high entropy FCC matrix and L1 2 ordered precipitates, so it is also named as "high entropy superalloy (HESA)". The tensile yield strengths of HESA surpass those of the reported HEAs from room temperature to elevated temperatures; furthermore, its creep resistance at 982 °C can be compared to those of some Ni-based superalloys. Analysis on experimental results indicate that HESA could be strengthened by the low stacking-fault energy of the matrix, high anti-phase boundary energy of the strengthening precipitate, and thermally stable microstructure. Positive misfit between FCC matrix and precipitate has yielded parallel raft microstructure during creep at 982 °C, and the creep curves of HESA were dominated by tertiary creep behavior. To the best of authors' knowledge, this article is the first to present the elevated temperature tensile creep study on full scale specimens of a high entropy alloy, and the potential of HESA for high temperature structural application is discussed.

High transition temperature superconducting integrated circuit

International Nuclear Information System (INIS)

DiIorio, M.S.

1985-01-01

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

High temperature corrosion in gasifiers

Directory of Open Access Journals (Sweden)

Bakker Wate

2004-01-01

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

High-temperature carbonates in the Stillwater Complex, Montana, USA

Science.gov (United States)

Aird, H. M.; Boudreau, A. E.

2012-12-01

The processes involved in the petrogenesis of the sulphide-hosted platinum-group-element (PGE) deposits of the Stillwater Complex are controversial, with theories ranging from the purely magmatic to those involving an aqueous fluid. To further constrain these models, we have been examining the trace phase assemblages in rocks away from the ore zones. High-temperature carbonates have been observed in association with sulphide minerals below the platiniferous J-M Reef of the Stillwater Complex. The carbonate assemblage consists of dolomite with exsolved calcite and is found in contact with sulphide minerals: chalcopyrite and pyrrhotite in the Peridotite Zone; and pyrrhotite with pentlandite, pyrite and chalcopyrite in Gabbronorite I of the Lower Banded Series. The minimal silicate alteration and the lack of greenschist minerals in association with the mineral assemblage are consistent with a high-temperature origin for the carbonates. The calcite-dolomite geothermometer [1] yields a minimum formation temperature of ~900°C for the unmixed assemblages. A reaction rim surrounds the carbonate-sulphide assemblages, showing an alteration of the host orthopyroxene to a more Ca-enriched, Fe-depleted composition. This is consistent with diffusive exchange between carbonates and pyroxenes at high temperatures, mediated by an aqueous fluid. The highly variable molar MnO/FeO ratios in both the high-temperature carbonates and their associated altered pyroxene rims also imply their interaction with a fluid. The carbonate assemblages are consistent with Stillwater fluid inclusion studies [2], showing that fluids comprising coexisting Cl-rich brine and carbonic fluid were trapped in pegmatitic quartz at 700-715°C, some of which also contained "accidental" calcite inclusions. The high Cl-content of apatite [3] found below the platiniferous J-M Reef is further evidence that a Cl-rich fluid was migrating through the rocks beneath the Reef. Carbonates have been shown to be stabilized

HYFIRE: fusion-high temperature electrolysis system

International Nuclear Information System (INIS)

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

1980-01-01

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

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

A novel SOI pressure sensor for high temperature application

International Nuclear Information System (INIS)

Li Sainan; Liang Ting; Wang Wei; Hong Yingping; Zheng Tingli; Xiong Jijun

2015-01-01

The silicon on insulator (SOI) high temperature pressure sensor is a novel pressure sensor with high-performance and high-quality. A structure of a SOI high-temperature pressure sensor is presented in this paper. The key factors including doping concentration and power are analyzed. The process of the sensor is designed with the critical process parameters set appropriately. The test result at room temperature and high temperature shows that nonlinear error below is 0.1%, and hysteresis is less than 0.5%. High temperature measuring results show that the sensor can be used for from room temperature to 350 °C in harsh environments. It offers a reference for the development of high temperature piezoresistive pressure sensors. (semiconductor devices)

High temperature thermometric phosphors for use in a temperature sensor

Science.gov (United States)

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

1998-01-01

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

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

Czech Academy of Sciences Publication Activity Database

Lukáš, Petr; Kunz, Ludvík; Svoboda, Milan

2002-01-01

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

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...

Potentialities of high temperature reactors (HTR)

International Nuclear Information System (INIS)

Hittner, D.

2001-01-01

This articles reviews the assets of high temperature reactors concerning the amount of radioactive wastes produced. 2 factors favors HTR-type reactors: high thermal efficiency and high burn-ups. The high thermal efficiency is due to the high temperature of the coolant, in the case of the GT-MHR project (a cooperation between General Atomic, Minatom, Framatome, and Fuji Electric) designed to burn Russian military plutonium, the expected yield will be 47% with an outlet helium temperature of 850 Celsius degrees. The high temperature of the coolant favors a lot of uses of the heat generated by the reactor: urban heating, chemical processes, or desalination of sea water.The use of a HTR-type reactor in a co-generating way can value up to 90% of the energy produced. The high burn-up is due to the technology of HTR-type fuel that is based on encapsulation of fuel balls with heat-resisting materials. The nuclear fuel of Fort-Saint-Vrain unit (Usa) has reached values of burn-ups from 100.000 to 120.000 MWj/t. It is shown that the quantity of unloaded spent fuel can be divided by 4 for the same amount of electricity produced, in the case of the GT-MHR project in comparison with a light water reactor. (A.C.)

ASD-1000: High-resolution, high-temperature acetylene spectroscopic databank

Science.gov (United States)

Lyulin, O. M.; Perevalov, V. I.

2017-11-01

We present a high-resolution, high-temperature version of the Acetylene Spectroscopic Databank called ASD-1000. The databank contains the line parameters (position, intensity, Einstein coefficient for spontaneous emission, term value of the lower states, self- and air-broadening coefficients, temperature dependence exponents of the self- and air-broadening coefficients) of the principal isotopologue of C2H2. The reference temperature for line intensity is 296 K and the intensity cutoff is 10-27 cm-1/(molecule cm-2) at 1000 K. The databank has 33,890,981 entries and covers the 3-10,000 cm-1 spectral range. The databank is based on the global modeling of the line positions and intensities performed within the framework of the method of effective operators. The parameters of the effective Hamiltonian and the effective dipole moment operator have been fitted to the observed values of the line positions and intensities collected from the literature. The broadening coefficients as well as their temperature dependence exponents were calculated using the empirical equations. The databank is useful for studying high-temperature radiative properties of C2H2. ASD-1000 is freely accessible via the Internet site of V.E. Zuev Institute of Atmospheric Optics SB RAS ftp://ftp.iao.ru/pub/ASD1000/.

First demonstration report on the high temperature materials data Bank of JRC

International Nuclear Information System (INIS)

1983-01-01

The High Temperature Materials Programme of the Joint Research Centre has among its activities a project which has the objective to develop a computerised data bank containing mechanical property data of alloys for high temperature applications. The pilot phase of this project during the multiannual programme 1980-1983 is restricted to a few alloys and properties. The present scope comprises tensile, creep and fatigue test results with emphasis on 600-1000 0 C test temperature and C-O-H environments for alloys covered by the specifications of the ''Alloy 800'' group. The data bank is now operational. This report is the first presentation of the data bank characteristics, contents and some output illustrations. It contains a descriptive part on the system and its structure and on the characteristics and quantity of the present data, and an illustrative part showing examples of data bank processed output. The selected print-outs are generated by interactive on-line searches and subsequent numerical or graphical processing in the data bank facilities at Petten and Ispra which are linked by EURONET

Influence of phase transformations on the mechanical behaviour of refractory ceramics at high temperature

International Nuclear Information System (INIS)

Schmitt, N.; Poirier, J.

2009-01-01

Refractories used at high temperature are subjected to high chemical and mechanical stresses. The mastery of their microstructure as well as the phase changes occurring in service is essential to ensure resistance to wear and failure of refractory linings. Great progress has been made: combining efficient techniques for the investigation of the microstructure with powerful numerical tools (thermochemical and thermo-mechanical computations) provides information (e.g., degradation mechanisms) that cannot be obtained directly. Also multi-physical and multi-scale models developing materials with high-performance for higher temperature and with longer lifetime. In this paper, through several examples we show some interactions between the mechanical behavior and the microstructure transformations of refractory ceramics. The tools developed to characterize their microstructure change in situ (e.g., at high temperature) and to identify their kinetics are described. Some methodologies and tools developed in recent years, today, provide a better understanding of in-service behavior of refractories while identifying the critical material and process parameters likely to increase life-time. (authors)

High-Temperature Lead-Free Solder Alternatives: Possibilities and Properties

DEFF Research Database (Denmark)

High-temperature solders have been widely used as joining materials to provide stable interconnections that resist a severe thermal environment and also to facilitate the drive for miniaturization. High-lead containing solders have been commonly used as high-temperature solders. The development...... of high-temperature lead-free solders has become an important issue for both the electronics and automobile industries because of the health and environmental concerns associated with lead usage. Unfortunately, limited choices are available as high-temperature lead-free solders. This work outlines...... the criteria for the evaluation of a new high-temperature lead-free solder material. A list of potential ternary high-temperature lead-free solder alternatives based on the Au-Sn and Au-Ge systems is proposed. Furthermore, a comprehensive comparison of the high-temperature stability of microstructures...

Flux motion and dissipation in high temperature superconductors

International Nuclear Information System (INIS)

Tinkham, M.

1991-01-01

Two quite different motivations spark the study of flux motion and resistance in the new high-temperature superconductors. Achievement of usefully low resistance at usefully large current densities is the key to most practical applications, but conceptual understanding of the idealized resistive behavior in the O current limit motivates much theoretical work. Some analyses emphasize the pinning of individual flux lines to inhomogeneities in the underlying material; others emphasize the collective aspects of the interacting flux lines, whether liquid, solid, crystalline, or glassy; still others emphasize the concept of percolative Josephson coupling between grains. In this paper an overview is given of these various approaches, their interrelation, and the experiment evidence, including some new results on flux motion in large SNS arrays, treated as a model system

Rovibrational coupling in molecular nitrogen at high temperature: An atomic-level study

Energy Technology Data Exchange (ETDEWEB)

Valentini, Paolo, E-mail: vale0142@umn.edu; Norman, Paul, E-mail: norma198@umn.edu; Zhang, Chonglin, E-mail: zhang993@umn.edu; Schwartzentruber, Thomas E., E-mail: schwart@aem.umn.edu [Department of Aerospace Engineering and Mechanics, College of Science and Engineering, University of Minnesota, Minneapolis, Minnesota 55455 (United States)

2014-05-15

This article contains an atomic-level numerical investigation of rovibrational relaxation in molecular nitrogen at high temperature (>4000 K), neglecting dissociation. We conduct our study with the use of pure Molecular Dynamics (MD) and Classical Trajectory Calculations (CTC) Direct Simulation Monte Carlo (DSMC), verified to produce statistically identical results at the conditions of interest here. MD and CTC DSMC solely rely on the specification of a potential energy surface: in this work, the site-site Ling-Rigby potential. Additionally, dissociation is prevented by modeling the N–N bond either as a harmonic or an anharmonic spring. The selected molecular model was shown to (i) recover the shear viscosity (obtained from equilibrium pure MD Green-Kubo calculations) of molecular nitrogen over a wide range of temperatures, up to dissociation; (ii) predict well the near-equilibrium rotational relaxation behavior of N{sub 2}; (iii) reproduce vibrational relaxation times in excellent accordance with the Millikan-White correlation and previous semi-classical trajectory calculations in the low temperature range, i.e., between 4000 K and 10 000 K. By simulating isothermal relaxations in a periodic box, we found that the traditional two-temperature model assumptions become invalid at high temperatures (>10 000 K), due to a significant coupling between rotational and vibrational modes for bound states. This led us to add a modification to both the Jeans and the Landau-Teller equations to include a coupling term, essentially described by an additional relaxation time for internal energy equilibration. The degree of anharmonicity of the N{sub 2} bond determines the strength of the rovibrational coupling. Although neglecting N{sub 2} dissociation only provides a partial description of a nitrogen system at very high temperatures, high-energy trends for bound-bound transitions are essential to understand nonequilibrium gas flows, with possible implications on rovibration

Rovibrational coupling in molecular nitrogen at high temperature: An atomic-level study

International Nuclear Information System (INIS)

Valentini, Paolo; Norman, Paul; Zhang, Chonglin; Schwartzentruber, Thomas E.

2014-01-01

This article contains an atomic-level numerical investigation of rovibrational relaxation in molecular nitrogen at high temperature (>4000 K), neglecting dissociation. We conduct our study with the use of pure Molecular Dynamics (MD) and Classical Trajectory Calculations (CTC) Direct Simulation Monte Carlo (DSMC), verified to produce statistically identical results at the conditions of interest here. MD and CTC DSMC solely rely on the specification of a potential energy surface: in this work, the site-site Ling-Rigby potential. Additionally, dissociation is prevented by modeling the N–N bond either as a harmonic or an anharmonic spring. The selected molecular model was shown to (i) recover the shear viscosity (obtained from equilibrium pure MD Green-Kubo calculations) of molecular nitrogen over a wide range of temperatures, up to dissociation; (ii) predict well the near-equilibrium rotational relaxation behavior of N 2 ; (iii) reproduce vibrational relaxation times in excellent accordance with the Millikan-White correlation and previous semi-classical trajectory calculations in the low temperature range, i.e., between 4000 K and 10 000 K. By simulating isothermal relaxations in a periodic box, we found that the traditional two-temperature model assumptions become invalid at high temperatures (>10 000 K), due to a significant coupling between rotational and vibrational modes for bound states. This led us to add a modification to both the Jeans and the Landau-Teller equations to include a coupling term, essentially described by an additional relaxation time for internal energy equilibration. The degree of anharmonicity of the N 2 bond determines the strength of the rovibrational coupling. Although neglecting N 2 dissociation only provides a partial description of a nitrogen system at very high temperatures, high-energy trends for bound-bound transitions are essential to understand nonequilibrium gas flows, with possible implications on rovibration

High temperature oxidation behavior of ODS steels

Science.gov (United States)

Kaito, T.; Narita, T.; Ukai, S.; Matsuda, Y.

2004-08-01

Oxide dispersion strengthened (ODS) steels are being developing for application as advanced fast reactor cladding and fusion blanket materials, in order to allow increased operation temperature. Oxidation testing of ODS steel was conducted under a controlled dry air atmosphere to evaluate the high temperature oxidation behavior. This showed that 9Cr-ODS martensitic steels and 12Cr-ODS ferritic steels have superior high temperature oxidation resistance compared to 11 mass% Cr PNC-FMS and 17 mass% Cr ferritic stainless steel. This high temperature resistance is attributed to earlier formation of the protective α-Cr 2O 3 on the outer surface of ODS steels.

Survey of high-temperature nuclear heat application

International Nuclear Information System (INIS)

Kirch, N.; Schaefer, M.

1984-01-01

Nuclear heat application at high temperatures can be divided into two areas - use of high-temperature steam up to 550 deg. C and use of high-temperature helium up to about 950 deg. C. Techniques of high-temperature steam and heat production and application are being developed in several IAEA Member States. In all these countries the use of steam for other than electricity production is still in a project definition phase. Plans are being discussed about using steam in chemical industries, oil refineries and for new synfuel producing plants. The use of nuclear generated steam for oil recovery from sands and shale is also being considered. High-temperature nuclear process heat production gives new possibilities for the application of nuclear energy - hard coals, lignites, heavy oils, fuels with problems concerning transport, handling and pollution can be converted into gaseous or liquid energy carriers with no loss of their energy contents. The main methods for this conversion are hydrogasification with hydrogen generated by nuclear heated steam reformers and steam gasification. These techniques will allow countries with large coal resources to replace an important part of their natural gas and oil consumption. Even countries with no fossil fuels can benefit from high-temperature nuclear heat - hydrogen production by thermochemical water splitting, nuclear steel making, ammonia production and the chemical heat-pipe system are examples in this direction. (author)

Temperature and light intensity interaction on Cercospora coffeicola sporulation and conidia germination

Directory of Open Access Journals (Sweden)

Marília Goulart da Silva

2016-04-01

Full Text Available ABSTRACT Difficulty in obtaining abundant sporulation in culture of many species of Cercospora may be the limiting factor for studies of biology, systematics, and inoculation of the genus. Therefore, it is necessary to understand the nutritional and environmental requirements that influence mycelial growth, sporulation and germination. As it is difficult to obtain conidia of Cercospora coffeicola in vitro, different temperatures (17, 22, 27, and 32 °C and light intensities (80, 160, 240, and 320 μmol m-2 s-1 were evaluated to optimize pathogen sporulation and assess favorable conditions for spore germination, aiming for a strategy of disease control. The dark treatment (0 μmol m-2 s-1 was added for sporulation. A significant interaction was found between temperature and light intensity for both variables. The highest sporulation rate of C. coffeicola occurred at a light intensity of 240 μmol m-2 s-1 and air temperature of 22 °C, reaching 5.9x106 con mL-1. Germination was higher at temperature 17 °C and light intensity of 320 μmol m-2 s-1, reaching 52%. Interaction between light intensity and temperature proved to influence the processes of sporulation and germination of C. coffeicola.

Hardness of high-pressure high-temperature treated single-walled carbon nanotubes

International Nuclear Information System (INIS)

Kawasaki, S.; Nojima, Y.; Yokomae, T.; Okino, F.; Touhara, H.

2007-01-01

We have performed high-pressure high-temperature (HPHT) treatments of high quality single-walled carbon nanotubes (SWCNTs) over a wide pressure-temperature range up to 13 GPa-873 K and have investigated the hardness of the HPHT-treated SWCNTs using a nanoindentation technique. It was found that the hardness of the SWCNTs treated at pressures greater than 11 GPa and at temperatures higher than 773 K is about 10 times greater than that of the SWCNTs treated at low temperature. It was also found that the hardness change of the SWCNTs is related to the structural change by the HPHT treatments which was based on synchrotron X-ray diffraction measurements

High temperature resistant cermet and ceramic compositions

Science.gov (United States)

Phillips, W. M. (Inventor)

1978-01-01

Cermet compositions having high temperature oxidation resistance, high hardness and high abrasion and wear resistance, and particularly adapted for production of high temperature resistant cermet insulator bodies are presented. The compositions are comprised of a sintered body of particles of a high temperature resistant metal or metal alloy, preferably molybdenum or tungsten particles, dispersed in and bonded to a solid solution formed of aluminum oxide and silicon nitride, and particularly a ternary solid solution formed of a mixture of aluminum oxide, silicon nitride and aluminum nitride. Also disclosed are novel ceramic compositions comprising a sintered solid solution of aluminum oxide, silicon nitride and aluminum nitride.

Interactive Effect of Air-Water Ratio and Temperature on the Air ...

African Journals Online (AJOL)

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KEYWORDS: Interactive effect, air-water ratio, temperature, volatile organic compounds, removal efficiency. [Received ... The rate of mass transfer of a VOC from wastewater to the ... where ΔHo is heat of evaporation of 1 mole of component.

Laser-Machined Microcavities for Simultaneous Measurement of High-Temperature and High-Pressure

Directory of Open Access Journals (Sweden)

Zengling Ran

2014-08-01

Full Text Available Laser-machined microcavities for simultaneous measurement of high-temperature and high-pressure are demonstrated. These two cascaded microcavities are an air cavity and a composite cavity including a section of fiber and an air cavity. They are both placed into a pressure chamber inside a furnace to perform simultaneous pressure and high-temperature tests. The thermal and pressure coefficients of the short air cavity are ~0.0779 nm/°C and ~1.14 nm/MPa, respectively. The thermal and pressure coefficients of the composite cavity are ~32.3 nm/°C and ~24.4 nm/MPa, respectively. The sensor could be used to separate temperature and pressure due to their different thermal and pressure coefficients. The excellent feature of such a sensor head is that it can withstand high temperatures of up to 400 °C and achieve precise measurement of high-pressure under high temperature conditions.

Laser-machined microcavities for simultaneous measurement of high-temperature and high-pressure.

Science.gov (United States)

Ran, Zengling; Liu, Shan; Liu, Qin; Huang, Ya; Bao, Haihong; Wang, Yanjun; Luo, Shucheng; Yang, Huiqin; Rao, Yunjiang

2014-08-07

Laser-machined microcavities for simultaneous measurement of high-temperature and high-pressure are demonstrated. These two cascaded microcavities are an air cavity and a composite cavity including a section of fiber and an air cavity. They are both placed into a pressure chamber inside a furnace to perform simultaneous pressure and high-temperature tests. The thermal and pressure coefficients of the short air cavity are ~0.0779 nm/°C and ~1.14 nm/MPa, respectively. The thermal and pressure coefficients of the composite cavity are ~32.3 nm/°C and ~24.4 nm/MPa, respectively. The sensor could be used to separate temperature and pressure due to their different thermal and pressure coefficients. The excellent feature of such a sensor head is that it can withstand high temperatures of up to 400 °C and achieve precise measurement of high-pressure under high temperature conditions.

Impact of hydrodynamic interactions on protein folding rates depends on temperature

Science.gov (United States)

Zegarra, Fabio C.; Homouz, Dirar; Eliaz, Yossi; Gasic, Andrei G.; Cheung, Margaret S.

2018-03-01

We investigated the impact of hydrodynamic interactions (HI) on protein folding using a coarse-grained model. The extent of the impact of hydrodynamic interactions, whether it accelerates, retards, or has no effect on protein folding, has been controversial. Together with a theoretical framework of the energy landscape theory (ELT) for protein folding that describes the dynamics of the collective motion with a single reaction coordinate across a folding barrier, we compared the kinetic effects of HI on the folding rates of two protein models that use a chain of single beads with distinctive topologies: a 64-residue α /β chymotrypsin inhibitor 2 (CI2) protein, and a 57-residue β -barrel α -spectrin Src-homology 3 domain (SH3) protein. When comparing the protein folding kinetics simulated with Brownian dynamics in the presence of HI to that in the absence of HI, we find that the effect of HI on protein folding appears to have a "crossover" behavior about the folding temperature. This means that at a temperature greater than the folding temperature, the enhanced friction from the hydrodynamic solvents between the beads in an unfolded configuration results in lowered folding rate; conversely, at a temperature lower than the folding temperature, HI accelerates folding by the backflow of solvent toward the folded configuration of a protein. Additionally, the extent of acceleration depends on the topology of a protein: for a protein like CI2, where its folding nucleus is rather diffuse in a transition state, HI channels the formation of contacts by favoring a major folding pathway in a complex free energy landscape, thus accelerating folding. For a protein like SH3, where its folding nucleus is already specific and less diffuse, HI matters less at a temperature lower than the folding temperature. Our findings provide further theoretical insight to protein folding kinetic experiments and simulations.

Chemical and microstructural changes at high temperature in tungsten wire reinforced metal-matrix composite materials

International Nuclear Information System (INIS)

Eaton, H.C.; Norden, H.

1985-01-01

Tungsten wire reinforced metal-matrix composites have been developed as a gas turbine blade material. Initially it was thought desirable to employ nickel or iron based superalloys as the matrix material due to their demonstrated reliability in applications where a high degree of dimensional stability, and thermal and mechanical fatigue resistance are required. It has been found, however, that deleterious fiber/matrix interactions occur in these systems under in-service conditions. These interactions seriously degrade the mechanical properties, and there is an effective lowering of the recrystallization temperature of the tungsten to the degree that grain structure changes can take place at unusually low temperatures. The present communication reports a study of the early stages of these interactions. Several microscopic and analytical techniques are used: TEM, SIMS, FIM, and the field ion atom probe. The nickel/tungsten interaction is thought to involve solute atom transport along grain boundaries. The grain boundary chemistry after short exposures to nickel at 1100 0 C is determined. In this manner the precursor interaction mechanisms are observed. These observations suggest that the strong nickel/tungsten grain boundary interactions do not involve the formation of distinct alloy phases, but instead involve rapid diffusion of essentially unalloyed nickel along the grain boundaries

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

International Nuclear Information System (INIS)

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

1984-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

1984-08-01

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

Development of high temperature turbine

Energy Technology Data Exchange (ETDEWEB)

Takahara, Kitao; Nouse, Hiroyuki; Yoshida, Toyoaki; Minoda, Mitsuhiro; Matsusue, Katsutoshi; Yanagi, Ryoji

1988-07-01

For the contribution to the development of FJR710, high by-pass ratio turbofan engine, with the study for many years of the development of high efficiency turbine for the jet engine, the first technical prize from the Energy Resource Research Committee was awarded in April, 1988. This report introduced its technical contents. In order to improve the thermal efficiency and enlarge the output, it is very effective to raise the gas temperature at the inlet of gas turbine. For its purpose, by cooling the nozzle and moving blades and having those blades operate at lower temperature than that of the working limitation, they realized, for the first time in Japan, the technique of cooling turbine to heighten the operational gas temperature. By that technique, it was enabled to raise the gas temperature at the inlet of turbine, to 1,350/sup 0/C from 850/sup 0/C. This report explain many important points of study covering the basic test, visualizing flow experiment, material discussion and structural design in the process of development. (9 figs)

Surface properties of magnetite in high temperature aqueous electrolyte solutions: A review.

Science.gov (United States)

Vidojkovic, Sonja M; Rakin, Marko P

2017-07-01

Deposits and scales formed on heat transfer surfaces in power plant water/steam circuits have a significant negative impact on plant reliability, availability and performance, causing tremendous economic consequences and subsequent increases in electricity cost. Consequently, the improvement of the understanding of deposition mechanisms on power generating surfaces is defined as a high priority in the power industry. The deposits consist principally of iron oxides, which are steel corrosion products and usually present in colloidal form. Magnetite (Fe 3 O 4 ) is the predominant and most abundant compound found in water/steam cycles of all types of power plants. The crucial factor that governs the deposition process and influences the deposition rate of magnetite is the electrostatic interaction between the metal wall surfaces and the suspended colloidal particles. However, there is scarcity of data on magnetite surface properties at elevated temperatures due to difficulties in their experimental measurement. In this paper a generalized overview of existing experimental data on surface characteristics of magnetite at high temperatures is presented with particular emphasis on possible application in the power industry. A thorough analysis of experimental techniques, mathematical models and results has been performed and directions for future investigations have been considered. The state-of-the-art assessment showed that for the characterization of magnetite/aqueous electrolyte solution interface at high temperatures acid-base potentiometric titrations and electrophoresis were the most beneficial and dependable techniques which yielded results up to 290 and 200°C, respectively. Mass titrations provided data on magnetite surface charge up to 320°C, however, this technique is highly sensitive to the minor concentrations of impurities present on the surface of particle. Generally, fairly good correlation between the isoelectric point (pH iep ) and point of zero charge

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.

Mechanically activated self-propagated high-temperature synthesis of nanometer-structured MgB2

International Nuclear Information System (INIS)

Radev, D.D.; Marinov, M.; Tumbalev, V.; Radev, I.; Konstantinov, L.

2005-01-01

Nanometer-sized MgB 2 was prepared via a two-step modification of the mechanically activated self-propagated high-temperature synthesis. The experimental conditions and some structural and phase characteristics of the synthesized product are reported. It is shown that a single-phase material can be prepared after 2 h of intense mechanical treatment of the starting magnesium and boron powders and a synthesis induced at a current-pulse density of 30 A cm -2 . The average size of MgB 2 particles synthesized in this way is 70-80 nm. It is also shown that using the same reagents and the 'classic' high-temperature interaction at 850 deg C with a protective atmosphere of pure Ar, mean particle size of the MgB 2 obtained is 50 μm

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

Energy Technology Data Exchange (ETDEWEB)

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

2009-07-01

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

High temperature deformation behavior, thermal stability and irradiation performance in Grade 92 steel

Science.gov (United States)

Alsagabi, Sultan

The 9Cr-2W ferritic-martensitic steel (i.e. Grade 92 steel) possesses excellent mechanical and thermophysical properties; therefore, it has been considered to suit more challenging applications where high temperature strength and creep-rupture properties are required. The high temperature deformation mechanism was investigated through a set of tensile testing at elevated temperatures. Hence, the threshold stress concept was applied to elucidate the operating high temperature deformation mechanism. It was identified as the high temperature climb of edge dislocations due to the particle-dislocation interactions and the appropriate constitutive equation was developed. In addition, the microstructural evolution at room and elevated temperatures was investigated. For instance, the microstructural evolution under loading was more pronounced and carbide precipitation showed more coarsening tendency. The growth of these carbide precipitates, by removing W and Mo from matrix, significantly deteriorates the solid solution strengthening. The MX type carbonitrides exhibited better coarsening resistance. To better understand the thermal microstructural stability, long tempering schedules up to 1000 hours was conducted at 560, 660 and 760°C after normalizing the steel. Still, the coarsening rate of M23C 6 carbides was higher than the MX-type particles. Moreover, the Laves phase particles were detected after tempering the steel for long periods before they dissolve back into the matrix at high temperature (i.e. 720°C). The influence of the tempering temperature and time was studied for Grade 92 steel via Hollomon-Jaffe parameter. Finally, the irradiation performance of Grade 92 steel was evaluated to examine the feasibility of its eventual reactor use. To that end, Grade 92 steel was irradiated with iron (Fe2+) ions to 10, 50 and 100 dpa at 30 and 500°C. Overall, the irradiated samples showed some irradiation-induced hardening which was more noticeable at 30°C. Additionally

Preparation of high performance NBR/HNTs nanocomposites using an electron transferring interaction method

Science.gov (United States)

Yang, Shuyan; Zhou, Yanxue; Zhang, Peng; Cai, Zhuodi; Li, Yangping; Fan, Hongbo

2017-12-01

Interfacial interaction is one of the key factors to improve comprehensive properties of polymer/inorganic filler nanocomposites. In this work, a new interfacial interaction called electron transferring interaction is reported in the nitrile-butadiene rubber/halloysite nanotubes (NBR/HNTs) nanocomposites. The X-ray photoelectron spectroscopy (XPS) and in-situ controlling temperature Fourier transform infrared spectroscopy (FTIR) have confirmed that electrons of electron-rich -CN groups in NBR can transfer to the electron-deficiency aluminum atoms of HNTs, which packs a part of NBR molecules onto the surface of HNTs to form bound rubber and stabilize the homogeneous dispersion of HNTs with few agglomeration as revealed by scanning electron microscope (SEM) and dynamic mechanical analysis (DMA) performances, even at high HNTs addition, resulting in high light transmittance. The tensile strength of NBR/30wt%HNTs nanocomposites is about 291% higher than pure NBR, without sacrificing the elongation at break.

Properties of ammonium ion-water clusters: analyses of structure evolution, noncovalent interactions, and temperature and humidity effects.

Science.gov (United States)

Pei, Shi-Tu; Jiang, Shuai; Liu, Yi-Rong; Huang, Teng; Xu, Kang-Ming; Wen, Hui; Zhu, Yu-Peng; Huang, Wei

2015-03-26

Although ammonium ion-water clusters are abundant in the biosphere, some information regarding these clusters, such as their growth route, the influence of temperature and humidity, and the concentrations of various hydrated clusters, is lacking. In this study, theoretical calculations are performed on ammonium ion-water clusters. These theoretical calculations are focused on determining the following characteristics: (1) the pattern of cluster growth; (2) the percentages of clusters of the same size at different temperatures and humidities; (3) the distributions of different isomers for the same size clusters at different temperatures; (4) the relative strengths of the noncovalent interactions for clusters of different sizes. The results suggest that the dipole moment may be very significant for the ammonium ion-water system, and some new stable isomers were found. The nucleation of ammonium ions and water molecules is favorable at low temperatures; thus, the clusters observed at high altitudes might not be present at low altitudes. High humidity can contribute to the formation of large ammonium ion-water clusters, whereas the formation of small clusters may be favorable under low-humidity conditions. The potential energy surfaces (PES) of these different sized clusters are complicated and differ according to the distribution of isomers at different temperatures. Some similar structures are observed between NH4(+)(H2O)n and M(H2O)n (where M represents an alkali metal ion or water molecule); when n = 8, the clusters begin to form the closed-cage geometry. As the cluster size increases, these interactions become progressively weaker. The successive binding energy at the DF-MP2-F12/VDZ-F12 level is better than that at the PW91PW91/6-311++G(3df, 3pd) level and is consistent with the experimentally determined values.

Spin Hall magnetoresistance at high temperatures

International Nuclear Information System (INIS)

Uchida, Ken-ichi; Qiu, Zhiyong; Kikkawa, Takashi; Iguchi, Ryo; Saitoh, Eiji

2015-01-01

The temperature dependence of spin Hall magnetoresistance (SMR) in Pt/Y 3 Fe 5 O 12 (YIG) bilayer films has been investigated in a high temperature range from room temperature to near the Curie temperature of YIG. The experimental results show that the magnitude of the magnetoresistance ratio induced by the SMR monotonically decreases with increasing the temperature and almost disappears near the Curie temperature. We found that, near the Curie temperature, the temperature dependence of the SMR in the Pt/YIG film is steeper than that of a magnetization curve of the YIG; the critical exponent of the magnetoresistance ratio is estimated to be 0.9. This critical behavior of the SMR is attributed mainly to the temperature dependence of the spin-mixing conductance at the Pt/YIG interface

High-pressure high-temperature experiments: Windows to the Universe

International Nuclear Information System (INIS)

Santaria-Perez, D.

2011-01-01

From Earth compositional arguments suggested by indirect methods, such as the propagation of seismic waves, is possible to generate in the laboratory pressure and temperature conditions similar to those of the Earth or other planet interiors and to study how these conditions affect to a certain metal or mineral. These experiments are, therefore, windows to the Universe. The aim of this chapter is to illustrate the huge power of the experimental high-pressure high-temperature techniques and give a global overview of their application to different geophysical fields. Finally, we will introduce the MALTA Consolider Team, which gather most of the Spanish high-pressure community, and present their available high-pressure facilities. (Author) 28 refs.

In Situ Observation of Gypsum-Anhydrite Transition at High Pressure and High Temperature

Institute of Scientific and Technical Information of China (English)

LIU Chuan-Jiang; ZHENG Hai-Fei

2012-01-01

An in-situ Raman spectroscopic study of gypsum-anhydrite transition under a saturated water condition at high pressure and high temperature is performed using a hydrothermal diamond anvil cell (HDAC).The experimental results show that gypsum dissolvs in water at ambient temperature and above 496 MPa.With increasing temperature,the anhydrite (CaSO4) phase precipitates at 250 320℃ in the pressure range of 1.0 1.5 GPa,indicating that under a saturated water condition,both stable conditions of pressure and temperature and high levels of Ca and SO4 ion concentrations in aqueous solution are essential for the formation of anhydrite.A linear relationship between the pressure and temperature for the precipitation of anhydrite is established as P(GPa) =0.0068T - 0.7126 (250℃≤T≤320℃).Anhydrite remained stable during rapid cooling of the sample chamber,showing that the gypsum-anhydrite transition involving both dissolution and precipitation processes is irreversible at high pressure and high temperature.%An in-situ Raman spectroscopic study of gypsum-anhydrite transition under a saturated water condition at high pressure and high temperature is performed using a hydrothermal diamond anvil cell (HDAC). The experimental results show that gypsum dissolvs in water at ambient temperature and above 496 Mpa. With increasing temperature, the anhydrite (CaSO4) phase precipitates at 250-320℃ in the pressure range of 1.0-1.5 Gpa, indicating that under a saturated water condition, both stable conditions of pressure and temperature and high levels of Ca and SO4 ion concentrations in aqueous solution are essential for the formation of anhydrite. A linear relationship between the pressure and temperature for the precipitation of anhydrite is established as P(Gpa) = 0.0068T - 0.7126 (250℃≤T≤320℃). Anhydrite remained stable during rapid cooling of the sample chamber, showing that the gypsum-anhydrite transition involving both dissolution and precipitation processes is

Symposium on high temperature and materials chemistry

International Nuclear Information System (INIS)

1989-10-01

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

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.

Temperature and rainfall interact to control carbon cycling in tropical forests.

Science.gov (United States)

Taylor, Philip G; Cleveland, Cory C; Wieder, William R; Sullivan, Benjamin W; Doughty, Christopher E; Dobrowski, Solomon Z; Townsend, Alan R

2017-06-01

Tropical forests dominate global terrestrial carbon (C) exchange, and recent droughts in the Amazon Basin have contributed to short-term declines in terrestrial carbon dioxide uptake and storage. However, the effects of longer-term climate variability on tropical forest carbon dynamics are still not well understood. We synthesised field data from more than 150 tropical forest sites to explore how climate regulates tropical forest aboveground net primary productivity (ANPP) and organic matter decomposition, and combined those data with two existing databases to explore climate - C relationships globally. While previous analyses have focused on the effects of either temperature or rainfall on ANPP, our results highlight the importance of interactions between temperature and rainfall on the C cycle. In cool forests (forests (> 20 °C) it consistently enhanced both ANPP and decomposition. At the global scale, our analysis showed an increase in ANPP with rainfall in relatively warm sites, inconsistent with declines in ANPP with rainfall reported previously. Overall, our results alter our understanding of climate - C cycle relationships, with high precipitation accelerating rates of C exchange with the atmosphere in the most productive biome on earth. © 2017 John Wiley & Sons Ltd/CNRS.

A unified treatment of high energy interactions

International Nuclear Information System (INIS)

Drescher, H.J.; Werner, K.; Ostapchenko, S.; Centre National de la Recherche Scientifique, 44 - Nantes

1999-01-01

It is well known that high energy interactions as different as electron-positron annihilation, deep inelastic lepton-nucleon scattering, proton-proton interactions, and nucleus-nucleus collisions have many features in common. Based upon this observation, a model for all these interactions is constructed which relies on the fundamental hypothesis that the behavior of high energy interactions is universal. (author)

Nuclear hyperfine interactions and chemical bonding in high TC superconductors

International Nuclear Information System (INIS)

Danon, J.

1987-01-01

Nuclear quadrupole resonances of Cu 63 and Fe 57 Moessbauer spectroscopy of the high temperature superconductor YBa 2 Cu 3 O 7-γ e described together with synchrotron radiation studies of the copper oxidation states in this material. The Moessbauer spectra of 57 Fe in the two distinct crystallographic sites of the Cu atoms in YBa 2 Cu 3 O 7-γ are very similar from the quadrupole coupling point of view although exhibiting markedly different values for the isomer shift. The role of oxygen vacancies in the hyperfine interactions is discussed. (author) [pt

High-Pressure High-Temperature Phase Diagram of the Organic Crystal Paracetamol

Science.gov (United States)

Smith, Spencer; Montgomery, Jeffrey; Vohra, Yogesh

High-pressure high-temperature (HPHT) Raman spectroscopy studies have been performed on the organic crystal paracetamol in a diamond anvil cell utilizing boron-doped diamond as heating anvil. The HPHT data obtained from boron-doped diamond heater is cross-checked with data obtained using a standard block heater diamond anvil cell. Isobaric measurements were conducted at pressures up to 8.5 GPa and temperature up to 520 K in a number of different experiments. Solid state phase transitions from monoclinic Form I --> orthorhombic Form II were observed at various pressures and temperatures as well as transitions from Form II --> unknown Form IV. The melting temperature for paracetamol was observed to increase with increasing pressures to 8.5 GPa. Our previous angle dispersive x-ray diffraction studies at the Advanced Photon Source has confirmed the existence of two unknown crystal structures Form IV and Form V of paracetamol at high pressure and ambient temperature. The phase transformation from Form II to Form IV occurs at ~8.5 GPa and from Form IV to Form V occurs at ~11 GPa at ambient temperature. Our new data is combined with the previous ambient temperature high-pressure Raman and X- ray diffraction data to create the first HPHT phase diagram of paracetamol. Doe-NNSA Carnegie DOE Alliance Center (CDAC) under Grant Number DE-NA0002006.

High Temperature Strength of Oxide Dispersion Strengthened Aluminium

DEFF Research Database (Denmark)

Clauer, A.H.; Hansen, Niels

1984-01-01

constant (except for the material with the lowest oxide content). The high temperature values of the modulus-corrected yield stresses are approximately two-thirds of the low temperature value. During high temperature creep, there is a definite indication of a threshold stress. This threshold stress......The tensile flow stress of coarse-grained dispersion strengthened Al-Al2O3 materials were measured as a function of temperature (77–873 K) and volume fraction (0.19-0.92 vol.%) of aluminium oxide. For the same material, the creep strength was determined as a function of temperature in the range 573......–873 K. The modulus-corrected yield stress (0.01 offset) is found to be temperature independent at low temperature (195–472 K). Between 473 and 573 K, the yield stress starts to decrease with increasing temperature. At high temperatures (573–873 K), the modulus-corrected yield stress is approximately...

Effective interactions between nanoparticles: Creating temperature-independent solvation environments for self-assembly

Energy Technology Data Exchange (ETDEWEB)

Yadav, Hari O. S., E-mail: cyz108802@chemistry.iitd.ac.in, E-mail: hariyadav.iitd@gmail.com; Shrivastav, Gourav; Agarwal, Manish; Chakravarty, Charusita [Department of Chemistry, Indian Institute of Technology-Delhi, New Delhi 110016 (India)

2016-06-28

The extent to which solvent-mediated effective interactions between nanoparticles can be predicted based on structure and associated thermodynamic estimators for bulk solvents and for solvation of single and pairs of nanoparticles is studied here. As a test of the approach, we analyse the strategy for creating temperature-independent solvent environments using a series of homologous chain fluids as solvents, as suggested by an experimental paper [M. I. Bodnarchuk et al., J. Am. Chem. Soc. 132, 11967 (2010)]. Our conclusions are based on molecular dynamics simulations of Au{sub 140}(SC{sub 10}H{sub 21}){sub 62} nanoparticles in n-alkane solvents, specifically hexane, octane, decane and dodecane, using the TraPPE-UA potential to model the alkanes and alkylthiols. The 140-atom gold core of the nanocrystal is held rigid in a truncated octahedral geometry and the gold-thiolate interaction is modeled using a Morse potential. The experimental observation was that the structural and rheological properties of n-alkane solvents are constant over a temperature range determined by equivalent solvent vapour pressures. We show that this is a consequence of the fact that long chain alkane liquids behave to a good approximation as simple liquids formed by packing of monomeric methyl/methylene units. Over the corresponding temperature range (233–361 K), the solvation environment is approximately constant at the single and pair nanoparticle levels under good solvent conditions. However, quantitative variations of the order of 10%–20% do exist in various quantities, such as molar volume of solute at infinite dilution, entropy of solvation, and onset distance for soft repulsions. In the opposite limit of a poor solvent, represented by vacuum in this study, the effective interactions between nanoparticles are no longer temperature-independent with attractive interactions increasing by up to 50% on decreasing the temperature from 361 K to 290 K, accompanied by an increase in

Interaction of Repetitively Pulsed High Energy Laser Radiation With Matter

Science.gov (United States)

Hugenschmidt, Manfred

1986-10-01

The paper is concerned with laser target interaction processes involving new methods of improving the overall energy balance. As expected theoretically, this can be achieved with high repetition rate pulsed lasers even for initially highly reflecting materials, such as metals. Experiments were performed by using a pulsed CO2 laser at mean powers up to 2 kW and repetition rates up to 100 Hz. The rates of temperature rise of aluminium for example were thereby increased by lore than a factor of 3 as compared to cw-radiation of comparable power density. Similar improvements were found for the overall absorptivities that were increased by this method by more than an order of magnitude.

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.

The interaction effects of temperature and humidity on emergency room visits for respiratory diseases in Beijing, China.

Science.gov (United States)

Su, Qin; Liu, Hongsheng; Yuan, Xiaoling; Xiao, Yan; Zhang, Xian; Sun, Rongju; Dang, Wei; Zhang, Jianbo; Qin, Yuhong; Men, Baozhong; Zhao, Xiaodong

2014-11-01

Few epidemiological studies have been reported as to whether there was any interactive effect between temperature and humidity on respiratory morbidity, especially in Asian countries. The present study used time-series analysis to explore the modification effects of humidity on the association between temperature and emergency room (ER) visits for respiratory, upper respiratory tract infection (URI), pneumonia, and bronchitis in Beijing between 2009 and 2011. Results showed that an obvious joint effect of temperature and humidity was revealed on ER visits for respiratory, URI, pneumonia, and bronchitis. Below temperature threshold, the temperature effect was stronger in low humidity level and presented a trend fall with humidity level increase. The effect estimates per 1 °C increase in temperature in low humidity level were -2.88 % (95 % confidence interval (CI) -3.08, -2.67) for all respiratory, -3.24 % (-3.59, -2.88) for URI, -1.48 % (-1.93, -1.03) for pneumonia, and -3.79 % (-4.37, -3.21) for bronchitis ER visits, respectively. However, above temperature threshold, temperature effect was greater in high humidity level and trending upward with humidity level increasing. In high humidity level, a 1 °C increase in temperature, the effect estimates were 1.84 % (1.55, 2.13) for all respiratory, 1.76 % (1.41, 2.11) for URI, and 7.48 % (4.41, 10.65) for bronchitis ER visits. But, there was no statistically significant for pneumonia. This suggests that the modifying effects of the humidity should be considered when analyzing health impacts of temperature.

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.

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

Science.gov (United States)

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

2018-04-01

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

Effect of In-situ Cure on Measurement of Glass Transition Temperatures in High-temperature Thermosetting Polymers

Science.gov (United States)

2015-01-01

TEMPERATURES IN HIGH-TEMPERATURE THERMOSETTING POLYMERS 5a. CONTRACT NUMBER In-House 5b. GRANT NUMBER 5c. PROGRAM ELEMENT NUMBER 6. AUTHOR(S...illustrated the difficulties inherent in measurement of the glass transition temperature of this high-temperature thermosetting polymer via dynamic...copyright protection in the United States. EFFECT OF IN-SITU CURE ON MEASUREMENT OF GLASS TRANSITION TEMPERATURES IN HIGH-TEMPERATURE THERMOSETTING

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.

Packaging Technologies for High Temperature Electronics and Sensors

Science.gov (United States)

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

2013-01-01

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

Development of a fuel-rod simulator and small-diameter thermocouples for high-temperature, high-heat-flux tests in the Gas-Cooled Fast Reactor Core Flow Test Loop

International Nuclear Information System (INIS)

McCulloch, R.W.; MacPherson, R.E.

1983-03-01

The Core Flow Test Loop was constructed to perform many of the safety, core design, and mechanical interaction tests in support of the Gas-Cooled Fast Reactor (GCFR) using electrically heated fuel rod simulators (FRSs). Operation includes many off-normal or postulated accident sequences including transient, high-power, and high-temperature operation. The FRS was developed to survive: (1) hundreds of hours of operation at 200 W/cm 2 , 1000 0 C cladding temperature, and (2) 40 h at 40 W/cm 2 , 1200 0 C cladding temperature. Six 0.5-mm type K sheathed thermocouples were placed inside the FRS cladding to measure steady-state and transient temperatures through clad melting at 1370 0 C

Promising materials for HTGR high temperature heat exchangers

International Nuclear Information System (INIS)

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

1989-01-01

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

High temperature thermoelectric energy conversion

International Nuclear Information System (INIS)

Wood, C.

1986-01-01

Considerable advances were made in the late '50's and early early '60's in the theory and development of materials for high-temperature thermoelectric energy conversion. This early work culminated in a variety of materials, spanning a range of temperatures, with the product of the figure of merit, Z, and temperature, T, i.e., the dimensionless figure of merit, ZT, of the order of one. This experimental limitation appeared to be universal and led a number of investigators to explore the possibility that a ZT - also represents a theoretical limitation. It was found not to be so

High temperature and high pressure gas cell for quantitative spectroscopic measurements

DEFF Research Database (Denmark)

Christiansen, Caspar; Stolberg-Rohr, Thomine; Fateev, Alexander

2016-01-01

A high temperature and high pressure gas cell (HTPGC) has been manufactured for quantitative spectroscopic measurements in the pressure range 1-200 bar and temperature range 300-1300 K. In the present work the cell was employed at up to 100 bar and 1000 K, and measured absorption coefficients...... of a CO2-N2 mixture at 100 bar and 1000 K are revealed for the first time, exceeding the high temperature and pressure combinations previously reported. This paper discusses the design considerations involved in the construction of the cell and presents validation measurements compared against simulated...

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...

High-temperature fusion of a multielectron leviton

Science.gov (United States)

Moskalets, Michael

2018-04-01

The state of electrons injected onto the surface of the Fermi sea depends on temperature. The state is pure at zero temperature and is mixed at finite temperature. In the case of a single-electron injection, such a transformation can be detected as a decrease in shot noise with increasing temperature. In the case of a multielectron injection, the situation is subtler. The mixedness helps the development of quantum-mechanical exchange correlations between injected electrons, even if such correlations are absent at zero temperature. These correlations enhance the shot noise, which in part counteracts the reduction of noise with temperature. Moreover, at sufficiently high temperatures, the correlation contribution to noise predominates over the contribution of individual particles. As a result, in the system of N electrons, the apparent charge (which is revealed via the shot noise) is changed from e at zero temperature to N e at high temperatures. It looks like the exchange correlations glue electrons into one particle of total charge and energy. This point of view is supported by both charge noise and heat noise. Interestingly, in the macroscopic limit, N →∞ , the correlation contribution completely suppresses the effect of temperature on noise.

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

HYFIRE: a tokamak-high-temperature electrolysis system

International Nuclear Information System (INIS)

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

1980-01-01

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

HYFIRE: a tokamak-high-temperature electrolysis system

International Nuclear Information System (INIS)

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

1980-01-01

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

Spatial variation in near-ground radiation and low temperature. Interactions with forest vegetation

Energy Technology Data Exchange (ETDEWEB)

Blennow, K.

1997-10-01

Low temperature has a large impact on the survival and distribution of plants. Interactive effects with high irradiance lead to cold-induced photo inhibition, which may impact on the establishment and growth of tree seedlings. In this thesis, novel approaches are applied for relating the spatial variability in low temperature and irradiance to photosynthetic performance and growth of tree seedlings, and for modelling the micro- and local-scale spatial variations in low temperature for heterogeneous terrain. The methodologies include the development and use of a digital image analysis system for hemispherical photographs, the use of Geographic Information Systems (GIS) and statistical methods, field data acquisition of meteorological elements, plant structure, growth and photosynthetic performance. Temperature and amounts of intercepted direct radiant energy for seedlings on clear days (IDRE) were related to chlorophyll a fluorescence, and the dry weight of seedlings. The combination of increased IDRE with reduced minimum temperatures resulted in persistent and strong photo inhibition as the season progressed, with likely implications for the establishment of tree seedlings at forest edges, and within shelter wood. For models of spatial distribution of low air temperature, the sky view factor was used to parameterize the radiative cooling, whilst drainage, ponding and stagnation of cold air, and thermal properties of the ground were all considered. The models hint at which scales and processes govern the development of spatial variations in low temperature for the construction of corresponding mechanistic models. The methodology is well suited for detecting areas that will be frost prone after clearing of forest and for comparing the magnitudes of impacts on low air temperature of forest management practices, such as shelter wood and soil preparation. The results can be used to formulate ground rules for use in practical forestry 141 refs, 5 figs, 1 tab

New Waste Calciner High Temperature Operation

International Nuclear Information System (INIS)

Swenson, M.C.

2000-01-01

A new Calciner flowsheet has been developed to process the sodium-bearing waste (SBW) in the INTEC Tank Farm. The new flowsheet increases the normal Calciner operating temperature from 500 C to 600 C. At the elevated temperature, sodium in the waste forms stable aluminates, instead of nitrates that melt at calcining temperatures. From March through May 2000, the new high-temperature flowsheet was tested in the New Waste Calcining Facility (NWCF) Calciner. Specific test criteria for various Calciner systems (feed, fuel, quench, off-gas, etc.) were established to evaluate the long-term operability of the high-temperature flowsheet. This report compares in detail the Calciner process data with the test criteria. The Calciner systems met or exceeded all test criteria. The new flowsheet is a visible, long-term method of calcining SBW. Implementation of the flowsheet will significantly increase the calcining rate of SBW and reduce the amount of calcine produced by reducing the amount of chemical additives to the Calciner. This will help meet the future waste processing milestones and regulatory needs such as emptying the Tank Farm

High-temperature plasma physics

International Nuclear Information System (INIS)

Furth, H.P.

1988-03-01

Both magnetic and inertial confinement research are entering the plasma parameter range of fusion reactor interest. This paper reviews the individual and common technical problems of these two approaches to the generation of thermonuclear plasmas, and describes some related applications of high-temperature plasma physics

Short steel and concrete columns under high temperatures

Directory of Open Access Journals (Sweden)

A. E. P. G. A. Jacintho

Full Text Available The growing demand for knowledge about the effect of high temperatures on structures has stimulated increasing research worldwide. This article presents experimental results for short composite steel and concrete columns subjected to high temperatures in ovens with or without an axial compression load, numerically analyzes the temperature distribution in these columns after 30 and 60 minutes and compares them with experimental results. The models consist of concrete-filled tubes of three different thicknesses and two different diameters, and the concrete fill has conventional properties that remained constant for all of the models. The stress-strain behavior of the composite columns was altered after exposure to high temperatures relative to the same columns at room temperature, which was most evident in the 60-minute tests due to the higher temperatures reached. The computational analysis adopted temperature rise curves that were obtained experimentally.

Low cycle fatigue and creep fatigue behavior of alloy 617 at high temperature

International Nuclear Information System (INIS)

Cabet, Celine; Carroll, Laura; Wright, Richard

2013-01-01

Alloy 617 is the leading candidate material for an intermediate heat exchanger (IHX) application of the very high temperature nuclear reactor (VHTR), expected to have an outlet temperature as high as 950 C. Acceptance of Alloy 617 in Section III of the ASME Code for nuclear construction requires a detailed understanding of the creep-fatigue behavior. Initial creep-fatigue work on Alloy 617 suggests a more dominant role of environment with increasing temperature and/or hold times evidenced through changes in creep-fatigue crack growth mechanisms and failure life. Continuous cycle fatigue and creep-fatigue testing of Alloy 617 was conducted at 950 C and 0.3% and 0.6% total strain in air to simulate damage modes expected in a VHTR application. Continuous cycle fatigue specimens exhibited transgranular cracking. Intergranular cracking was observed in the creep-fatigue specimens and the addition of a hold time at peak tensile strain degraded the cycle life. This suggests that creep-fatigue interaction occurs and that the environment may be partially responsible for accelerating failure. (authors)

Dynamic high-temperature characterization of an iridium alloy in tension

Energy Technology Data Exchange (ETDEWEB)

Song, Bo [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Nelson, Kevin [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Jin, Helena [Sandia National Lab. (SNL-CA), Livermore, CA (United States); Lipinski, Ronald J. [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Bignell, John [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Ulrich, G. B. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); George, E. P. [Ruhr Univ., Bochum (Germany)

2015-09-01

Iridium alloys have been utilized as structural materials for certain high-temperature applications, due to their superior strength and ductility at elevated temperatures. The mechanical properties, including failure response at high strain rates and elevated temperatures of the iridium alloys need to be characterized to better understand high-speed impacts at elevated temperatures. A DOP-26 iridium alloy has been dynamically characterized in compression at elevated temperatures with high-temperature Kolsky compression bar techniques. However, the dynamic high-temperature compression tests were not able to provide sufficient dynamic high-temperature failure information of the iridium alloy. In this study, we modified current room-temperature Kolsky tension bar techniques for obtaining dynamic tensile stress-strain curves of the DOP-26 iridium alloy at two different strain rates (~1000 and ~3000 s-1) and temperatures (~750°C and ~1030°C). The effects of strain rate and temperature on the tensile stress-strain response of the iridium alloy were determined. The DOP-26 iridium alloy exhibited high ductility in stress-strain response that strongly depended on both strain rate and temperature.

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.

Applications of high-temperature superconductivity

International Nuclear Information System (INIS)

Malozemoff, A.P.; Gallagher, W.J.; Schwall, R.E.

1987-01-01

The new high temperature superconductors open up possibilities for applications in magnets, power transmission, computer interconnections, Josephson devices and instrumentation, among many others. The success of these applications hinges on many interlocking factors, including critical current density, critical fields, allowable processing temperatures, mechanical properties and chemical stability. An analysis of some of these factors suggests which applications may be the easiest to realize and which may have the greatest potential

Interactions between particulate air pollution and temperature in air pollution mortality time series studies

International Nuclear Information System (INIS)

Roberts, Steven

2004-01-01

In many community time series studies on the effect of particulate air pollution on mortality, particulate air pollution is modeled additively. In this study, we investigated the interaction between daily particulate air pollution and daily mean temperature in Cook County, Illinois and Allegheny County, Pennsylvania, using data for the period 1987-1994. This was done through the use of joint particulate air pollution-temperature response surfaces and by stratifying the effect of particulate air pollution on mortality by temperature. Evidence that the effect of particulate air pollution on mortality may depend on temperature is found. However, the results were sensitive to the number of degrees of freedom used in the confounder adjustments, the particulate air pollution exposure measure, and how the effects of temperature on mortality are modeled. The results were less sensitive to the estimation method used--generalized linear models and natural cubic splines or generalized additive models and smoothing splines. The results of this study suggest that in community particulate air pollution mortality time series studies the possibility of an interaction between daily particulate air pollution and daily mean temperature should be considered

Structural Variation of Alpha-synuclein with Temperature by a Coarse-grained Approach with Knowledge-based Interactions (Postprint)

Science.gov (United States)

2015-07-01

Alzheimer disease. ASN1,3 has been extensively studied as an intrinsically disordered (unstructured) protein with a monomeric conformation compa- rable to a...changes in these physical quantities occur by avoiding the low and high temperature extremes. Typical snapshots from the simulations as a function of...mobile as the residue-residue interactions become less impor- tant and the protein assumes a self- avoiding walk (SAW) or random coil conformation (vida

Structural behavior of reinforced concrete structures at high temperatures

International Nuclear Information System (INIS)

Yamazaki, N.; Yamazaki, M.; Mochida, T.; Mutoh, A.; Miyashita, T.; Ueda, M.; Hasegawa, T.; Sugiyama, K.; Hirakawa, K.; Kikuchi, R.; Hiramoto, M.; Saito, K.

1995-01-01

To establish a method to predict the behavior of reinforced concrete structures subjected simultaneously to high temperatures and external loads, this paper presents the results obtained in several series of tests carried out recently in Japan. This paper reports on the material properties of concrete and steel bars under high temperatures. It also considers the heat transfer properties of thick concrete walls under transient high temperatures, and the structural behavior of reinforced concrete beams subjected to high temperatures. In the tests, data up to 800 C were obtained for use in developing a computational method to estimate the non-linear behavior of reinforced concrete structures exposed to high temperatures. (orig.)

Quenching ilmenite with a high-temperature and high-pressure phase using super-high-energy ball milling.

Science.gov (United States)

Hashishin, Takeshi; Tan, Zhenquan; Yamamoto, Kazuhiro; Qiu, Nan; Kim, Jungeum; Numako, Chiya; Naka, Takashi; Valmalette, Jean Christophe; Ohara, Satoshi

2014-04-25

The mass production of highly dense oxides with high-temperature and high-pressure phases allows us to discover functional properties that have never been developed. To date, the quenching of highly dense materials at the gramme-level at ambient atmosphere has never been achieved. Here, we provide evidence of the formation of orthorhombic Fe2TiO4 from trigonal FeTiO3 as a result of the high-temperature (>1250 K) and high-pressure (>23 GPa) condition induced by the high collision energy of 150 gravity generated between steel balls. Ilmenite was steeply quenched by the surrounding atmosphere, when iron-rich ilmenite (Fe2TiO4) with a high-temperature and high-pressure phase was formed by planetary collisions and was released from the collision points between the balls. Our finding allows us to infer that such intense planetary collisions induced by high-energy ball milling contribute to the mass production of a high-temperature and high-pressure phase.

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.

High temperature superconductors applications in telecommunications

International Nuclear Information System (INIS)

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

1994-01-01

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

Elevated temperature erosion studies on some materials for high temperature applications

International Nuclear Information System (INIS)

Zhou Jianren.

1991-01-01

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

Hydrogen Production from Nuclear Energy via High Temperature Electrolysis

International Nuclear Information System (INIS)

James E. O'Brien; Carl M. Stoots; J. Stephen Herring; Grant L. Hawkes

2006-01-01

This paper presents the technical case for high-temperature nuclear hydrogen production. A general thermodynamic analysis of hydrogen production based on high-temperature thermal water splitting processes is presented. Specific details of hydrogen production based on high-temperature electrolysis are also provided, including results of recent experiments performed at the Idaho National Laboratory. Based on these results, high-temperature electrolysis appears to be a promising technology for efficient large-scale hydrogen production

Heat transfer from a high temperature condensable mixture

International Nuclear Information System (INIS)

Chan, S.H.; Cho, D.H.; Condiff, D.W.

1978-01-01

A new development in heat transfer is reported. It is concerned with heat transfer from a gaseous mixture that contains a condensable vapor and is at very high temperature. In the past, heat transfer associated with either a condensable mixture at low temperature or a noncondensable mixture at high temperature has been investigated. The former reduces to the classical problem of fog formation in, say, atmosphere where the rate of condensation is diffusion controlled (molecular or conductive diffusions). In the presence of noncondensable gases, heat transfer to a cooler boundary by this mechanism is known to be drastically reduced. In the latter case, where the high temperature mixture is noncondensable, radiative transfer may become dominant and a vast amount of existing literature exists on this class of problem. A fundamentally different type of problem of relevance to recent advances in open cycle MHD power plants and breeder reactor safety is considered. In the advanced coal-fired power plant using MHD as a topping cycle, a condensable mixture is encountered at temperatures of 2000 to 3000 0 . Condensation of the vaporized slag and seed materials at such a high temperature can take place in the MHD generator channel as well as in the radiant boiler. Similarly, in breeder reactor accident analyses involving hypothetical core disruptive accidents, a UO 2 vapor mixture at 400 0 K or higher is often considered. Since the saturation temperature of UO 2 at one atmosphere is close to 4000 0 K, condensation is also likely at a very high temperature. Accordingly, an objective of the present work is to provide an understanding of heat transfer and condensation mechanics insystems containing a high temperature condensable mixture. The results of the study show that, when a high temperature mixture is in contact with a cooler surface, a thermal boundary layer develops rapidly because of intensive radiative cooling from the mixture

Electronic phase separation and high temperature superconductors

International Nuclear Information System (INIS)

Kivelson, S.A.

1994-01-01

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

High temperature electronic gain device

International Nuclear Information System (INIS)

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

1979-01-01

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

High Temperature Superconductor Resonator Detectors

Data.gov (United States)

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

High temperature and high resolution uv photoelectron spectroscopy using supersonic molecular beams

International Nuclear Information System (INIS)

Wang, Lai-Sheng; Reutt-Robey, J.E.; Niu, B.; Lee, Y.T.; Shirley, D.A.

1989-07-01

A high temperature molecular beam source with electron bombardment heating has been built for high resolution photoelectron spectroscopic studies of high temperature species and clusters. This source has the advantages of: producing an intense, continuous, seeded molecular beam, eliminating the interference of the heating mechanism from the photoelectron measurement. Coupling the source with our hemispherical electron energy analyzer, we can obtain very high resolution HeIα (584 angstrom) photoelectron spectra of high temperature species. Vibrationally-resolved photoelectron spectra of PbSe, As 2 , As 4 , and ZnCl 2 are shown to demonstrate the performance of the new source. 25 refs., 8 figs., 1 tab

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...

Efficient dual layer interconnect coating for high temperature electrochemical devices

DEFF Research Database (Denmark)

Palcut, Marián; Mikkelsen, Lars; Neufeld, Kai

2012-01-01

Effects of novel dual layer coatings Co3O4/La0.85Sr0.15MnO3−δ on high temperature oxidation behaviour of candidate steels for interconnects are studied at 1123 K in flowing simulated ambient air (air + 1% H2O) and oxygen. Four alloys are investigated: Crofer 22 APU, Crofer 22 H, E-Brite and AL 29...... that the oxidation reaction is limited by outward Cr3+ diffusion in the chromia scale. The coating effectively reduces the oxidation rate. Reactions and cation inter-diffusion between the coating and the oxide scale are observed. Long term effects of these interactions are discussed and practical implications...

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

International Nuclear Information System (INIS)

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

1989-01-01

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

Mechanical properties of concrete for power reactor at high temperatures

International Nuclear Information System (INIS)

Kawase, Kiyotaka; Tanaka, Hitoshi; Nakano, Masayuki

1985-01-01

The purpose of this study is to investigate the mechanical properties of concrete for power reactor at high temperature. This paper presents the creep behavior of concrete at high temperature and the cause by which a specified aggregate is broken at a specified high temperature. The creep coefficient at high temperature is smaller than that at ordinary temperature. (author)

High temperature oxidation behavior of TiAl-based intermetallics

International Nuclear Information System (INIS)

Stroosnijder, M.F.; Sunderkoetter, J.D.; Haanappel, V.A.C.

1996-01-01

TiAl-based intermetallic compounds have attracted considerable interest as structural materials for high-temperature applications due to their low density and substantial mechanical strength at high temperatures. However, one major drawback hindering industrial application arises from the insufficient oxidation resistance at temperatures beyond 700 C. In the present contribution some general aspects of high temperature oxidation of TiAl-based intermetallics will be presented. This will be followed by a discussion of the influence of alloying elements, in particular niobium, and of the effect of nitrogen in the oxidizing environment on the high temperature oxidation behavior of such materials

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.

High Temperature Electrostrictive Ceramics, Phase I

Data.gov (United States)

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

HTGR fuel behavior at very high temperature

International Nuclear Information System (INIS)

Kashimura, Satoru; Ogawa, Touru; Fukuda, Kousaku; Iwamoto, Kazumi

1986-03-01

Fuel behavior at very high temperature simulating abnormal transient of the reactor operation and accidents have been investigated on TRISO coating LEU oxide particle fuels at JAERI. The test simulating the abnormal transient was carried out by irradiation of loose coated particles above 1600 deg C. The irradiation test indicated that particle failure was principally caused by kernel migration. For simulation of the core heat-up accident, two experiments of out-of-pile heating were made. Survival temperature limits were measured and fuel performance at very high temperature were investigated by the heatings. Study on the fuel behavior under reactivity initiated accident was made by NSRR(Nuclear Safety Research Reactor) pulse irradiation, where maximum temperature was higher than 2800 deg C. It was found in the pulse irradiation experiments that the coated particles incorporated in the compacts did not so severely fail unlike the loose coated particles at ultra high temperature above 2800 deg C. In the former particles UO 2 material at the center of the kernel vaporized, leaving a spherical void. (author)

High-temperature morphology of stepped gold surfaces

International Nuclear Information System (INIS)

Bilalbegovic, G.; Tosatti, E.; Ercolessi, F.

1992-04-01

Molecular dynamics simulations with a classical many-body potential are used to study the high-temperature stability of stepped non-melting metal surfaces. We have studied in particular the Au(111) vicinal surfaces in the (M+1, M-1, M) family and the Au(100) vicinals in the (M, 1, 1) family. Some vicinal orientations close to the non-melting Au(111) surface become unstable close to the bulk melting temperature and facet into a mixture of crystalline (111) regions and localized surface-melted regions. On the contrary, we do not find high-temperature faceting for vicinals close to Au(100), also a non-melting surface. These (100) vicinal surfaces gradually disorder with disappearance of individual steps well below the bulk melting temperature. We have also studied the high-temperature stability of ledges formed by pairs of monoatomic steps of opposite sign on the Au(111) surface. It is found that these ledges attract each other, so that several of them merge into one larger ledge, whose edge steps then act as a nucleation site for surface melting. (author). 43 refs, 8 figs

Strain-rate dependent fatigue behavior of 316LN stainless steel in high-temperature water

Energy Technology Data Exchange (ETDEWEB)

Tan, Jibo [CAS Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning Key Laboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Wu, Xinqiang, E-mail: xqwu@imr.ac.cn [CAS Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning Key Laboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Han, En-Hou; Ke, Wei; Wang, Xiang [CAS Key Laboratory of Nuclear Materials and Safety Assessment, Liaoning Key Laboratory for Safety and Assessment Technique of Nuclear Materials, Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016 (China); Sun, Haitao [Nuclear and Radiation Safety Center, SEPA, Beijing 100082 (China)

2017-06-15

Low cycle fatigue behavior of forged 316LN stainless steel was investigated in high-temperature water. It was found that the fatigue life of 316LN stainless steel decreased with decreasing strain rate from 0.4 to 0.004 %s{sup −1} in 300 °C water. The stress amplitude increased with decreasing strain rate during fatigue tests, which was a typical characteristic of dynamic strain aging. The fatigue cracks mainly initiated at pits and slip bands. The interactive effect between dynamic strain aging and electrochemical factors on fatigue crack initiation is discussed. - Highlights: •The fatigue lives of 316LN stainless steel decrease with decreasing strain rate. •Fatigue cracks mainly initiated at pits and persistent slip bands. •Dynamic strain aging promoted fatigue cracks initiation in high-temperature water.

Viscoelastic creep of high-temperature concrete

International Nuclear Information System (INIS)

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

1985-01-01

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

High Temperature Electro-Mechanical Devices For Nuclear Applications

International Nuclear Information System (INIS)

Robertson, D.

2010-01-01

Nuclear power plants require a number of electro-mechanical devices, for example, Control Rod Drive Mechanisms (CRDM's) to control the raising and lowering of control rods and Reactor Coolant Pumps (RCP's) to circulate the primary coolant. There are potential benefits in locating electro-mechanical components in areas of the plant with high ambient temperatures. One such benefit is the reduced need to make penetrations in pressure vessels leading to simplified plant design and improved inherent safety. The feature that limits the ambient temperature at which most electrical machines may operate is the material used for the electrical insulation of the machine windings. Conventional electrical machines generally use polymer-based insulation that limits the ambient temperature they can operate in to below 200 degrees Celsius. This means that when a conventional electrical machine is required to operate in a hot area it must be actively cooled necessitating additional systems. This paper presents data gathered during investigations undertaken by Rolls-Royce into the design of high temperature electrical machines. The research was undertaken at Rolls-Royce's University Technology Centre in Advanced Electrical Machines and Drives at Sheffield University. Rolls- Royce has also been investigating high temperature wire and encapsulants and latterly techniques to provide high temperature insulation to terminations. Rolls-Royce used the experience gained from these tests to produce a high temperature electrical linear actuator at sizes representative of those used in reactor systems. This machine was tested successfully at temperatures equivalent to those found inside the reactor vessel of a pressurised water reactor through a full series of operations that replicated in service duty. The paper will conclude by discussing the impact of the findings and potential electro-mechanical designs that may utilise such high temperature technologies. (authors)

Generating high temperature tolerant transgenic plants: Achievements and challenges.

Science.gov (United States)

Grover, Anil; Mittal, Dheeraj; Negi, Manisha; Lavania, Dhruv

2013-05-01

Production of plants tolerant to high temperature stress is of immense significance in the light of global warming and climate change. Plant cells respond to high temperature stress by re-programming their genetic machinery for survival and reproduction. High temperature tolerance in transgenic plants has largely been achieved either by over-expressing heat shock protein genes or by altering levels of heat shock factors that regulate expression of heat shock and non-heat shock genes. Apart from heat shock factors, over-expression of other trans-acting factors like DREB2A, bZIP28 and WRKY proteins has proven useful in imparting high temperature tolerance. Besides these, elevating the genetic levels of proteins involved in osmotic adjustment, reactive oxygen species removal, saturation of membrane-associated lipids, photosynthetic reactions, production of polyamines and protein biosynthesis process have yielded positive results in equipping transgenic plants with high temperature tolerance. Cyclic nucleotide gated calcium channel proteins that regulate calcium influxes across the cell membrane have recently been shown to be the key players in induction of high temperature tolerance. The involvement of calmodulins and kinases in activation of heat shock factors has been implicated as an important event in governing high temperature tolerance. Unfilled gaps limiting the production of high temperature tolerant transgenic plants for field level cultivation are discussed. Copyright © 2013 Elsevier Ireland Ltd. All rights reserved.

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

Science.gov (United States)

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

2016-05-01

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

500 C Electronic Packaging and Dielectric Materials for High Temperature Applications

Science.gov (United States)

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

2016-01-01

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