WorldWideScience

Sample records for bed high temperature

  1. Ultra high temperature particle bed reactor design

    Science.gov (United States)

    Lazareth, Otto; Ludewig, Hans; Perkins, K.; Powell, J.

    1990-01-01

    A direct nuclear propulsion engine which could be used for a mission to Mars is designed. The main features of this reactor design are high values for I(sub sp) and very efficient cooling. This particle bed reactor consists of 37 cylindrical fuel elements embedded in a cylinder of beryllium which acts as a moderator and reflector. The fuel consists of a packed bed of spherical fissionable fuel particles. Gaseous H2 passes over the fuel bed, removes the heat, and is exhausted out of the rocket. The design was found to be neutronically critical and to have tolerable heating rates. Therefore, this particle bed reactor design is suitable as a propulsion unit for this mission.

  2. Core Physics of Pebble Bed High Temperature Nuclear Reactors

    NARCIS (Netherlands)

    Auwerda, G.J.

    2014-01-01

    To more accurately predict the temperature distribution inside the reactor core of pebble bed type high temperature reactors, in this thesis we investigated the stochastic properties of randomly stacked beds and the effects of the non-homogeneity of these beds on the neutronics and thermal-hydraulic

  3. Effect of bed temperature and bed composition on agglomeration during gasification of high-sodium, high-sulphur lignite in a spouted fluidised bed

    Energy Technology Data Exchange (ETDEWEB)

    D.P. McCullough; P.J. Mullinger; P.J. Ashman [University of Adelaide, Adelaide, SA (Australia). Cooperative Research Centre for Clean Power from Lignite, School of Chemical Engineering

    2003-07-01

    Fluidised bed gasification (FBG) is an alternative process for coal utilisation that delivers improved efficiencies and lower temperature operation compared to conventional technology. Agglomeration and defluidisation are phenomena that have the potential to occur within fluidised bed reactors, which can interrupt stable process operation. While extensive work has been carried out investigating fluidised bed combustion of lignite, relatively little work has been carried out for lignite under fluidised bed gasification conditions. Gasification of high sodium, high sulphur content lignite in a spouted bed gasifier (SBG) indicates that agglomeration and defluidisation is only an issue when maximum bed temperature exceeds approximately 850{degree}C and air/fuel ratios of 2.5 outside of these conditions, defluidisation is not detected. It is also demonstrated that defluidisation occurs before agglomeration, rather than as a result of agglomeration as previously thought. The Rosin-Rammler method of describing particle size distribution is found to yield appropriate variables for quantification of the extent of agglomeration taking place in cases where defluidisation is a factor. However, it has been shown by this method that while initial results indicated that agglomeration extent varies directly with maximum bed temperature, further results have shown that other variables, such as superficial velocity, have a significant impact on the extent of agglomeration. Investigations are currently continuing. 9 refs., 8 figs., 9 tabs.

  4. Experimental investigation of thermal de-stratification in rock bed TES systems for high temperature applications

    International Nuclear Information System (INIS)

    Highlights: • High thermal stratifications exists rock bed TES when charge with high temperature heat. • Faster thermal degradation occurs in highly stratified bed irrespective of the bed length. • Average rate of heat loss as a function of storage time increases with increasing average bed temperature. - Abstract: Solar energy fluctuates so much that it cannot promote continuous use. Integration of Thermal Energy Storage (TES) with solar energy collection devices has the potential of making solar energy available on demand. Thermal energy can be stored in a bed of rocks at temperatures suitable for applications like cooking, boiling space heating, etc. During charging, temperature stratification is observed in the bed. In a stratified system, if the heat is used immediately, then it is possible to extract heat at reasonably high temperature from the top. For cases where the system is to be used after sometime (later at night or the following morning), the high temperature heat at the top is observed to degrade as the system tries to establish thermal equilibrium irrespective of the bed height. The average rate of heat loss from the TES unit to the ambient is found to increase with increasing average bed temperatures

  5. Hydrogenation of Aliphatic Alkenes in a High-Temperature High-Pressure Packed-Bed Microreactor

    OpenAIRE

    Stavárek, Petr

    2012-01-01

    This contribution presents results of the characterization of a new high-temperature high-pressure integrated packed-bed microreactor (MCTU 600 from Ehrfeld Mikrotechnik BTS GmbH) for lab-scale catalyst testing. As the model reaction we used the hydrogenation of C4-C5 aliphatic alkenes heterogeneously catalyzed by Pt/Al2O3 or Pd/Al2O3.

  6. Numerical Simulation of Accident Scenario in High Temperature Gas Cooled (Pebble Bed) Nuclear Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Peter, Geoffrey J. [Oregon Institute of Technology - Portland Center, Portland (United States)

    2012-03-15

    The accident scenario resulting from blockages due to the retention of dust in the coolant gas or from the rupture of one or more fuel particles used in the High Temperature Gas Cooled (Pebble Bed) Nuclear Reactors is considered in this paper. The next generation of Advanced High Temperature Reactors (AHTR), are considered for nuclear power production, and for high-temperature hydrogen production using nuclear reactors to reduce the carbon footprint. Blockages can cause LOCA variations in flow and heat transfer that may lead to hot spots within the bed that could compromise reactor safety. Therefore, it is important to know the void fraction distribution and the interstitial velocity field in the packed bed. The blockage for this numerical study simulated a region with significantly lower void than that in the rest of the bed. Finite difference technique solved the simplified continuity, momentum, and energy equations. Any meaningful outcome of the solution depended largely upon the validity of the boundary conditions. Among them, the inlet and outlet velocity profiles required special attention. Thus, a close approximation to these profiles obtained from an experimental set-up established the boundary conditions. This paper presents the development of the elliptic-partial equation for a bed of a bed of pebbles, and the solution procedure. The paper also discusses velocity and temperature profiles obtained from both numerical and experimental set-up, with and without effect of blockage. Based on the studies it is evident that knowledge of LOCA velocity and temperature distribution within the fuel element in a Pebble Bed Nuclear Reactor or AHTR is essential for reactor safety.

  7. High Temperature Convective Drying of a Packed Bed with Humid Air at Different Humidities

    Directory of Open Access Journals (Sweden)

    J. Sghaier

    2009-01-01

    Full Text Available Problem statement: Drying a packed bed of porous particle at high temperature with varying humidity of hot air is an attractive process. Despite, many researches on experimental and simulation on a fixed bed drying at low and average temperature are proposed. Few studies showed drying at high temperature with humid air or using superheated steam. The latest is compared to dry air. Approach: In this study, we show an experimental and numerical study of humid air drying of a fixed bed of moist porous alumina particles. The air velocity, the air temperature and the vapor pressure were varied from 1.7-2.3 m.sec-1, 120-160°C and 0.1-0.65 bar, respectively and the experiments were performed at atmospheric pressure. Then a mathematical describing heat and mass transfer during drying is developed. This model is based on the averaging volume approach using two scale changes. Results: From the experimental works, the solid temperature and the bed moisture content have been presented at different drying conditions. The previous results show that an increase in humidity leads to an increase of the wet bulb temperature and a decrease in the drying time. At the same drying temperature, the variation in the gas velocity affects also the drying time. In addition, we note that the drying time increases if the bed depth increases. The predicted results deduced from the developed model were compared with the experiment. Conclusion: The experimental and predicted results obtained from this study describing drying of a packed bed illustrate clearly the effect of the air humidity on the drying kinetics.

  8. Analysis of the fluid-bed stability of FCC catalysts at high temperature in terms of bed elasticity

    Institute of Scientific and Technical Information of China (English)

    Paola Lettieri; Luca Mazzer

    2008-01-01

    The effect of temperature on the fluid-bed stability of three FCC catalysts has been analyzed through considerations on fluid-bed elasticity. Experimental findings on the effect of temperature on the elasticity modulus at minimum bubbling conditions, (E)mb, were analyzed using the hydrodynamic fluid-bed stability model developed by Foscolo and Gibilaro (1984) and adopting the interparticle-forces-based stability criterion developed by Mutsers and Rietema (1977). For both models, the parameters which control changes in (E)mb with temperature are discussed, in order to establish the origin of the fluid-bed elasticity and analyze the ability of these models to discriminate between the relative importance of the hydrodynamic and interparticle forces on the stability of the fluidized catalysts.

  9. Thermal-hydraulics numerical analyses of Pebble Bed Advanced High Temperature Reactor hot channel

    International Nuclear Information System (INIS)

    Background: The thermal hydraulics behavior of the Pebble Bed Advanced High Temperature Reactor (PB-AHTR) hot channel was studied. Purpose: We aim to analyze the thermal-hydraulics behavior of the PB-AHTR, such as pressure drop, temperature distribution of coolant and pebble bed as well as thermal removal capacity in the condition of loss of partial coolant. Methods: We used a modified FLUENT code which was coupled with a local non-equilibrium porous media model by introducing a User Defined Scalar (UDS) in the calculation domain of the reactor core and subjoining different resistance terms (Ergun and KTA) to calculate the temperature of coolant, solid phase of pebble bed and pebble center in the core. Results: Computational results showed that the resistance factor has great influence on pressure drop and velocity distribution, but less impact on the temperature of coolant, solid phase of pebble bed and pebble center. We also confirmed the heat removal capacity of the PB-AHTR in the condition of nominal and loss of partial coolant conditions. Conclusion: The numerical analyses results can provide a useful proposal to optimize the design of PB-AHTR. (authors)

  10. Analytical model of an irrigated packed-bed direct-contact heat exchanger at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Bohn, M S

    1986-11-01

    This paper presents an analytical model of direct-contact heat exchange (DCHX) in an irrigated packed bed at high temperatures. The specific application is heat exchange between molten salt and air where the molten salt is a sensible heat storage medium and high temperature air is required for an end process. The model defines several heat transfer mechanisms between the three components in the bed - the liquid, the gas, and the packing. It also includes the effect of conduction in the packing. Correlations found in the literature are used to calculate the associated heat transfer coefficients. The model is restricted to liquids that wet the packing material and to gas/liquid flow rates below the loading point. Three dimensionless equations describe the heat balance between the three bed components. The resulting dimensionless parameters reveal that for commercial DCHX systems, radiation heat transfer is unimportant relative to the convective heat transfer, which is consistent with previous experimental results for air/mercury and nitrogen/molten lead systems. The model also predicts volumetric heat transfer coefficients of about 10,000 W/m/sup 3/K, which is consistent with experimental work.

  11. High temperature degradation by erosion-corrosion in bubbling fluidized bed combustors

    Energy Technology Data Exchange (ETDEWEB)

    Hou, Peggy Y.; MacAdam, S.; Niu, Y.; Stringer, J.

    2003-04-22

    Heat-exchanger tubes in fluidized bed combustors (FBCs) often suffer material loss due to combined corrosion and erosion. Most severe damage is believed to be caused by the impact of dense packets of bed material on the lower parts of the tubes. In order to understand this phenomenon, a unique laboratory test rig at Berkeley was designed to simulate the particle hammering interactions between in-bed particles and tubes in bubbling fluidized bed combustors. In this design, a rod shaped specimen is actuated a short distance within a partially fluidized bed. The downward specimen motion is controlled to produce similar frequencies, velocities and impact forces as those experienced by the impacting particle aggregates in practical systems. Room temperature studies have shown that the degradation mechanism is a three-body abrasion process. This paper describes the characteristics of this test rig, reviews results at elevated temperatures and compares them to field experience. At higher temperatures, deposits of the bed material on tube surfaces can act as a protective layer. The deposition depended strongly on the type of bed material, the degree of tube surface oxidation and the tube and bed temperatures. With HCl present in the bed, wastage was increased due to enhanced oxidation and reduced oxide scale adherence.

  12. Attrition of Dolomitic Lime in a Fluidized-Bed at High Temperature

    OpenAIRE

    Hartman, M; Svoboda, K.; Pohořelý, M. (Michael); Šyc, M. (Michal); Jeremiáš, M. (Michal)

    2013-01-01

    The results of an experimental study on the rate of attrition of quicklime catalyst/sorbent in a high-temperature, spouted fluidized bed with quartz sand are presented. Batchwise measurements were conducted at 850oC in an electrically heated gasification reactor of an inner diameter of 5.1 cm with two sizes (605 and 980 µm) of high-grade, dolomitic limestone calcine (quicklime, lime). In addition to the influence of the particle size, the effect of operating (elapsed) time was investigated at...

  13. High temperature CO2 capture using calcium oxide sorbent in a fixed-bed reactor

    International Nuclear Information System (INIS)

    The gas-solid reaction and breakthrough curve of CO2 capture using calcium oxide sorbent at high temperature in a fixed-bed reactor are of great importance, and being influenced by a number of factors makes the characterization and prediction of these a difficult problem. In this study, the operating parameters on reaction between solid sorbent and CO2 gas at high temperature were investigated. The results of the breakthrough curves showed that calcium oxide sorbent in the fixed-bed reactor was capable of reducing the CO2 level to near zero level with the steam of 10 vol%, and the sorbent in CaO mixed with MgO of 40 wt% had extremely low capacity for CO2 capture at 550 deg. C. Calcium oxide sorbent after reaction can be easily regenerated at 900 deg. C by pure N2 flow. The experimental data were analyzed by shrinking core model, and the results showed reaction rates of both fresh and regeneration sorbents with CO2 were controlled by a combination of the surface chemical reaction and diffusion of product layer.

  14. Conceptual design study of Pebble Bed Type High Temperature Gas-cooled Reactor with annular core structure

    International Nuclear Information System (INIS)

    This report presents the Conceptual Design Study of Pebble Bed Type High Temperature Gas-cooled Reactor with Annular Core Structure. From this study, it is made clear that the thermal power of the Pebble Bed Type Reactor can be increased to 500MW through introducing the annular core structure without losing the inherent safe characteristics (in the coolant depressurization accident, the fuel temperature does not exceed the temperature where the fuel defect begins.) This thermal power is two times higher than the inherent safe Pebble Bed Type High temperature Gas-cooled Reactor (MHTGR) designed in West Germany. From this result, it is foreseen that the ratio of the plant cost to the reactor power is reduced and the economy of the plant operation is improved. The reactor performances e.g. fuel burnup and fuel temperature are maintained in same level of the MHTGR. (author)

  15. Plutonium and minor actinide utilisation in a pebble-bed high temperature reactor

    International Nuclear Information System (INIS)

    This paper contains results of the analysis of the pebble-bed high temperature gas-cooled PUMA reactor loaded with plutonium and minor actinide (Pu/MA) fuel. Starting from knowledge and experience gained in the Euratom FP5 projects HTR-N and HTR-N1, this study aims at demonstrating the potential of high temperature reactors to utilize or transmute Pu/MA fuel. The work has been performed within the Euratom FP6 project PUMA. A number of different fuel types and fuel configurations have been analyzed and compared with respect to incineration performance and safety-related reactor parameters. The results show the excellent plutonium and minor actinide burning capabilities of the high temperature reactor. The largest degree of incineration is attained in the case of an HTR fuelled by pure plutonium fuel as it remains critical at very deep burnup of the discharged pebbles. Addition of minor actinides to the fuel leads to decrease of the achievable discharge burnup and therefore smaller fraction of actinides incinerated during reactor operation. The inert-matrix fuel design improves the transmutation performance of the reactor, while the 'wallpaper' fuel does not have advantage over the standard fuel design in this respect. After 100 years of decay following the fuel discharge, the total amount of actinides remains almost unchanged for all of the fuel types considered. Among the plutonium isotopes, only the amount of Pu-241 is reduced significantly due to its relatively short half-life. (authors)

  16. Plutonium and minor actinide utilisation in a pebble-bed high temperature reactor

    Energy Technology Data Exchange (ETDEWEB)

    Petrov, B. Y.; Kuijper, J. C.; Oppe, J.; De Haas, J. B. M. [Nuclear Research and Consultancy Group, Westerduinweg 3, 1755 ZG Petten (Netherlands)

    2012-07-01

    This paper contains results of the analysis of the pebble-bed high temperature gas-cooled PUMA reactor loaded with plutonium and minor actinide (Pu/MA) fuel. Starting from knowledge and experience gained in the Euratom FP5 projects HTR-N and HTR-N1, this study aims at demonstrating the potential of high temperature reactors to utilize or transmute Pu/MA fuel. The work has been performed within the Euratom FP6 project PUMA. A number of different fuel types and fuel configurations have been analyzed and compared with respect to incineration performance and safety-related reactor parameters. The results show the excellent plutonium and minor actinide burning capabilities of the high temperature reactor. The largest degree of incineration is attained in the case of an HTR fuelled by pure plutonium fuel as it remains critical at very deep burnup of the discharged pebbles. Addition of minor actinides to the fuel leads to decrease of the achievable discharge burnup and therefore smaller fraction of actinides incinerated during reactor operation. The inert-matrix fuel design improves the transmutation performance of the reactor, while the 'wallpaper' fuel does not have advantage over the standard fuel design in this respect. After 100 years of decay following the fuel discharge, the total amount of actinides remains almost unchanged for all of the fuel types considered. Among the plutonium isotopes, only the amount of Pu-241 is reduced significantly due to its relatively short half-life. (authors)

  17. Feasibility of Thorium Fuel Cycles in a Very High Temperature Pebble-Bed Hybrid System

    Directory of Open Access Journals (Sweden)

    L.P. Rodriguez

    2015-08-01

    Full Text Available Nuclear energy presents key challenges to be successful as a sustainable energy source. Currently, the viability of the use thorium-based fuel cycles in an innovative nuclear energy generation system is being investigated in order to solve these key challenges. In this work, the feasibility of three thorium-based fuel cycles (232Th-233U, 232Th-239Pu, and 232Th-U in a hybrid system formed by a Very High Temperature Pebble-Bed Reactor (VHTR and two Pebble-Bed Accelerator Driven Systems (ADSs was evaluated using parameters related to the neutronic behavior such as nuclear fuel breeding, minor actinide stockpile, the energetic contribution of each fissile isotope, and the radiotoxicity of the long lived wastes. These parameters were used to compare the fuel cycles using the well-known MCNPX ver. 2.6e computational code. The results obtained confirm that the 232Th-233U fuel cycle is the best cycle for minimizing the production of plutonium isotopes and minor actinides. Moreover, the inclusion of the second stage in the ADSs demonstrated the possibility of extending the burnup cycle duration and reducing the radiotoxicity of the discharged fuel from the VHTR.

  18. Design of fuzzy PID controller for high temperature pebble bed reactor

    Energy Technology Data Exchange (ETDEWEB)

    Badgujar, Kushal D.; Satpute, Satchidanand R.; Revankara, Shripad T.; Lee, John C.; Kim, Moo Hwan [POSTECH, Pohang (Korea, Republic of)

    2012-10-15

    Control system is most important characteristic to be considered to control spontaneous fission reaction in the design of the nuclear reactor. Recently fuzzy based control systems have been designed and applied as control system for nuclear plants. This article emphasize on controlling the power of the high temperature pebble bed reactor (HTPBR) with the design of Fuzzy proportional integral derivative (PID) controller. A simplified reactor model with point kinetics equation and reactor heat balance equation is used. The reactivity feedback arising from power coefficient of reactivity and Xenon poisoning is also considered. The reactor is operated at various power levels by using fuzzy PID controller. The fuzzy logic eliminates the necessity of the tuning the gains of PID controller each time by extending the finite sets of the PID controller gains.

  19. Application of a moving bed biofilm reactor for tertiary ammonia treatment in high temperature industrial wastewater.

    Science.gov (United States)

    Shore, Jennifer L; M'Coy, William S; Gunsch, Claudia K; Deshusses, Marc A

    2012-05-01

    This study examines the use of a moving bed biofilm reactor (MBBR) as a tertiary treatment step for ammonia removal in high temperature (35-45°C) effluents, and quantifies different phenotypes of ammonia and nitrite oxidizing bacteria responsible for nitrification at elevated temperatures. Bench scale reactors operating at 35 and 40°C were able to successfully remove greater than 90% of the influent ammonia (up to 19 mg L(-1) NH(3)-N) in both the synthetic and industrial wastewater. No biotreatment was observed at 45°C, although effective nitrification was rapidly recovered when the temperature was lowered to 30°C. Using qPCR, Nitrosomonas oligotropha was found to be the dominant ammonia oxidizing bacterium in the biofilm for the first phases of reactor operation. In the later phases, Nitrosomonas nitrosa was observed and its increased presence may have been responsible for improved ammonia treatment efficiency. Accumulation of nitrite in some instances appeared to correlate with temporary low presence of Nitrospira spp.

  20. Progress in the Development of the Modular Pebble-Bed Advanced High Temperature Reactor

    International Nuclear Information System (INIS)

    This review article summarizes recent progress by students and faculty at U.C. Berkeley working on the development of the Pebble-Bed Advanced High Temperature Reactor (PB-AHTR). The 410-MWe PBAHTR is a liquid salt cooled reactor that operates at near atmospheric pressure and high power density (20 to 30 MW/m3, compared to 4.8 MW/m3 for helium cooled reactors). Operating with a core inlet temperature of 600 deg. C and outlet temperature of 704 deg. C, the PB-AHTR uses well understood materials of construction including Alloy 800H with Hastelloy N cladding for the reactor vessel and primary loop components, and graphite for core and reflector structures. Recent work by the NE 170 senior design class has developed physical arrangements for the major reactor and power conversion components, along with the structural design for the reactor building and turbine hall featuring seismic base isolation, design for aircraft crash protection, shielding analysis, and design of a multiple-zone ventilation and containment system to provide effective control of radioactive and chemical contamination. The resulting total building volume is 260 m3/MWe, compared to 343 m3/MWe to 486 m3/MWe for current large (1150 to 1600 MWe) LWR designs. These results suggest the potential for significant reductions in construction time and cost. Neutronics studies have verified the capability to design the PB-AHTR with negative fuel and coolant temperature reactivity coefficients, for both LEU and deep-burn TRU fuels. Depletion analysis was also performed to identify optimal core designs to maximize fuel utilization. The additional moderation provided by the coolant simplifies design to achieve optimal moderation, and the spent fuel volume is approximately half that of helium cooled reactors. In collaboration with the Czech Nuclear Research Institute, initial zero-power critical tests were performed to validate PB-AHTR neutronics models. Liquid salts are unique among candidate reactor coolants due

  1. A kinetic study of gaseous potassium capture by coal minerals in a high temperature fixed-bed reactor

    DEFF Research Database (Denmark)

    Zheng, Yuanjing; Jensen, Peter Arendt; Jensen, Anker Degn

    2008-01-01

    The reactions between gaseous potassium chloride and coal minerals were investigated in a lab-scale high temperature fixed-bed reactor using single sorbent pellets. The applied coal minerals included kaolin, mullite, silica, alumina, bituminous coal ash, and lignite coal ash that were formed...

  2. Sustainability of thorium-uranium in pebble-bed fluoride salt-cooled high temperature reactor

    Directory of Open Access Journals (Sweden)

    Zhu Guifeng

    2016-01-01

    Full Text Available Sustainability of thorium fuel in a Pebble-Bed Fluoride salt-cooled High temperature Reactor (PB-FHR is investigated to find the feasible region of high discharge burnup and negative Flibe (2LiF-BeF2 salt Temperature Reactivity Coefficient (TRC. Dispersion fuel or pellet fuel with SiC cladding and SiC matrix is used to replace the tristructural-isotropic (TRISO coated particle system for increasing fuel loading and decreasing excessive moderation. To analyze the neutronic characteristics, an equilibrium calculation method of thorium fuel self-sustainability is developed. We have compared two refueling schemes (mixing flow pattern and directional flow pattern and two kinds of reflector materials (SiC and graphite. This method found that the feasible region of breeding and negative Flibe TRC is between 20 vol% and 62 vol% fuel loading in the fuel. A discharge burnup could be achieved up to about 200 MWd/kgHM. The case with directional flow pattern and SiC reflector showed superior burnup characteristics but the worst radial power peak factor, while the case with mixing flow pattern and SiC reflector, which was the best tradeoff between discharge burnup and radial power peak factor, could provide burnup of 140 MWd/kgHM and about 1.4 radial power peak factor with 50 vol% dispersion fuel. In addition, Flibe salt displays good neutron properties as a coolant of quasi-fast reactors due to the strong 9Be(n,2n reaction and low neutron absorption of 6Li (even at 1000 ppm in fast spectrum. Preliminary thermal hydraulic calculation shows good safety margin. The greatest challenge of this reactor may be the decades irradiation time of the pebble fuel.

  3. Analysis of Fluid Flow and Heat Transfer Model for the Pebble Bed High Temperature Gas Cooled Reactor

    Directory of Open Access Journals (Sweden)

    S. Yamoah

    2012-06-01

    Full Text Available The pebble bed type high temperature gas cooled nuclear reactor is a promising option for next generation reactor technology and has the potential to provide high efficiency and cost effective electricity generation. The reactor unit heat transfer poses a challenge due to the complexity associated with the thermalflow design. Therefore to reliably simulate the flow and heat transport of the pebble bed modular reactor necessitates a heat transfer model that deals with radiation as well as thermal convection and conduction. In this study, a model with the capability to simulate fluid flow and heat transfer in the pebble bed modular reactor core has been developed. The developed model was implemented on a personal computer using FORTRAN 95 programming language. Several important fluid flow and heat transfer parameters have been examined: including the pressure drop over the reactor core, the heat transfer coefficient, the Nusselt number and the effective thermal conductivity of the fuel pebbles. Results obtained from the simulation experiments show a uniform pressure in the radial direction for a core to fuel element diameter (D/d ratio>20 and the heat transfer coefficient increases with increasing temperature and coolant mass flow rate. The model can adequately account for the flow and heat transfer phenomenon and the loss of pressure through friction in the pebble bed type high temperature nuclear reactor.

  4. Experimental Study on an On-Line Measurement of High Temperature Circulating Ash Flux in a Circulating Fluidized Bed Boiler

    Institute of Scientific and Technical Information of China (English)

    Lu Xiaofeng; Li Yourong

    2001-01-01

    A new kind of measuring method that may be used to measure high temperature circulating solid particles flux in a circulating fluidized bed boiler is studied in this paper. The measuring method is founded on the principle of thermal equilibrium. A series of cold tests and hot tests were carried to optimize the structure and collocation of water-cooling tubes and showed that the method had the advantage of simple, accurate, reliable and good applicability for on-line usage in a circulating fluidized bed boiler.

  5. Very High Temperature Reactor (VHTR) Deep Burn Core and Fuel Analysis -- Complete Design Selection for the Pebble Bed Reactor

    Energy Technology Data Exchange (ETDEWEB)

    B. Boer; A. M. Ougouag

    2010-09-01

    The Deep-Burn (DB) concept focuses on the destruction of transuranic nuclides from used light water reactor fuel. These transuranic nuclides are incorporated into TRISO coated fuel particles and used in gas-cooled reactors with the aim of a fractional fuel burnup of 60 to 70% in fissions per initial metal atom (FIMA). This high performance is expected through the use of multiple recirculation passes of the fuel in pebble form without any physical or chemical changes between passes. In particular, the concept does not call for reprocessing of the fuel between passes. In principle, the DB pebble bed concept employs the same reactor designs as the presently envisioned low-enriched uranium core designs, such as the 400 MWth Pebble Bed Modular Reactor (PBMR-400). Although it has been shown in the previous Fiscal Year (2009) that a PuO2 fueled pebble bed reactor concept is viable, achieving a high fuel burnup, while remaining within safety-imposed prescribed operational limits for fuel temperature, power peaking and temperature reactivity feedback coefficients for the entire temperature range, is challenging. The presence of the isotopes 239-Pu, 240-Pu and 241-Pu that have resonances in the thermal energy range significantly modifies the neutron thermal energy spectrum as compared to a ”standard,” UO2-fueled core. Therefore, the DB pebble bed core exhibits a relatively hard neutron energy spectrum. However, regions within the pebble bed that are near the graphite reflectors experience a locally softer spectrum. This can lead to power and temperature peaking in these regions. Furthermore, a shift of the thermal energy spectrum with increasing temperature can lead to increased absorption in the resonances of the fissile Pu isotopes. This can lead to a positive temperature reactivity coefficient for the graphite moderator under certain operating conditions. The effort of this task in FY 2010 has focused on the optimization of the core to maximize the pebble discharge

  6. Mechanisms and kinetics of high-temperature cadmium sorption by packed bed of calcined kaolin.

    Science.gov (United States)

    Yang, H C; Yun, J S; Kang, M J; Kang, Y; Kim, J H

    2001-01-01

    Sorption experiments by passing CdCl2-carrying flue gas through the packed bed of calcined macro-porous kaolin particles were performed over a temperature range of 973-1173K and a CdCl2 partial pressure range of 8-16.1 Pa. The observed structural change of the sorbent mineral at the stage of sorption and the results of desorption tests revealed the characteristics of an irreversible chemical reaction as a major cadmium capturing mechanism. In the fully saturated kaolin sorbent, CdO x Al2O x 2SiO2 is present as a sorption reaction product together with a smaller amount of 2CdO x Al2O x 2SiO2. The increase in sorbent bed temperature resulted in an increase in the rate of sorption, but it had no effect on maximum cadmium uptake. The gas-phase CdCl2 diffusion into the macro pores of calcined kaolin had a negligible effect on the overall sorption rate. The reaction between gaseous CdCl2 and solid Al2O3 x 2SiO2 is very sensitive to the concentration of CdCl2 but relatively insensitive to the temperature of the sorbent bed. The order of reaction with respect to the CdCl2 vapor concentration was determined to be 3.26. The activation energy, Ea, was estimated as 5.56 kcal/mol according to the Arrhenius relationship. PMID:11688684

  7. Pebble Bed Reactors Design Optimization Methods and their Application to the Pebble Bed Fluoride Salt Cooled High Temperature Reactor (PB-FHR)

    Science.gov (United States)

    Cisneros, Anselmo Tomas, Jr.

    The Fluoride salt cooled High temperature Reactor (FHR) is a class of advanced nuclear reactors that combine the robust coated particle fuel form from high temperature gas cooled reactors, direct reactor auxillary cooling system (DRACS) passive decay removal of liquid metal fast reactors, and the transparent, high volumetric heat capacitance liquid fluoride salt working fluids---flibe (33%7Li2F-67%BeF)---from molten salt reactors. This combination of fuel and coolant enables FHRs to operate in a high-temperature low-pressure design space that has beneficial safety and economic implications. In 2012, UC Berkeley was charged with developing a pre-conceptual design of a commercial prototype FHR---the Pebble Bed- Fluoride Salt Cooled High Temperature Reactor (PB-FHR)---as part of the Nuclear Energy University Programs' (NEUP) integrated research project. The Mark 1 design of the PB-FHR (Mk1 PB-FHR) is 236 MWt flibe cooled pebble bed nuclear heat source that drives an open-air Brayton combine-cycle power conversion system. The PB-FHR's pebble bed consists of a 19.8% enriched uranium fuel core surrounded by an inert graphite pebble reflector that shields the outer solid graphite reflector, core barrel and reactor vessel. The fuel reaches an average burnup of 178000 MWt-d/MT. The Mk1 PB-FHR exhibits strong negative temperature reactivity feedback from the fuel, graphite moderator and the flibe coolant but a small positive temperature reactivity feedback of the inner reflector and from the outer graphite pebble reflector. A novel neutronics and depletion methodology---the multiple burnup state methodology was developed for an accurate and efficient search for the equilibrium composition of an arbitrary continuously refueled pebble bed reactor core. The Burnup Equilibrium Analysis Utility (BEAU) computer program was developed to implement this methodology. BEAU was successfully benchmarked against published results generated with existing equilibrium depletion codes VSOP

  8. High temperature gas-cooled pebble bed reactor steady state thermal-hydraulics analyses based on CFD method

    International Nuclear Information System (INIS)

    Background: Based on general purpose CFD code Fluent, the PBMR-400 full load nominal condition thermal-hydraulics performance was studied by applying local thermal non-equilibrium porous media model. Purpose: In thermal hydraulics study of the gas cooled pebble bed reactor, the core of the reactor can be treated as macroscopic porous media with strong inner heat source, and the original Fluent code can not handle it properly. Methods: By introducing a UDS in the calculation domain of the reactor core and subjoining a new resistance term, we develop a non-equilibrium porous media model which can give an accurate description of the core of the pebble bed. The mesh of CFD code is finer than that of the traditional pebble bed reactor thermal hydraulics analysis code such as THERMIX and TINTE, thus more information about coolant velocity fields, temperature field and solid phase temperature field can be acquired. Results: The nominal condition calculation results of the CFD code are compared to those of the well-established thermal-hydraulic code THERMIX and TINTE, and show a good consistency. Conclusion: The extended local thermal non-equilibrium model can be used to analyse thermal-hydraulics of high temperature pebble bed type reactor. (authors)

  9. Comparative evaluation of pebble-bed and prismatic fueled high-temperature gas-cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Kasten, P.R.; Bartine, D.E.

    1981-01-01

    A comparative evaluation has been performed of the HTGR and the Federal Republic of Germany's Pebble Bed Reactor (PBR) for potential commercial applications in the US. The evaluation considered two reactor sizes (1000 and 3000 MW(t)) and three process applications (steam cycle, direct cycle, and process heat, with outlet coolant temperatures of 750, 850, and 950/sup 0/C, respectively). The primary criterion for the comparison was the levelized (15-year) cost of producing electricity or process heat. Emphasis was placed on the cost impact of differences between the prismatic-type HTGR core, which requires periodic refuelings during reactor shutdowns, and the pebble bed PBR core, which is refueled continuously during reactor operations. Detailed studies of key technical issues using reference HTGR and PBR designs revealed that two cost components contributing to the levelized power costs are higher for the PBR: capital costs and operation and maintenance costs. A third cost component, associated with nonavailability penalties, tended to be higher for the PBR except for the process heat application, for which there is a large uncertainty in the HTGR nonavailability penalty at the 950/sup 0/C outlet coolant temperature. A fourth cost component, fuel cycle costs, is lower for the PBR, but not sufficiently lower to offset the capital cost component. Thus the HTGR appears to be slightly superior to the PBR in economic performance. Because of the advanced development of the HTGR concept, large HTGRs could also be commercialized in the US with lower R and D costs and shorter lead times than could large PBRs. It is recommended that the US gas-cooled thermal reactor program continue giving primary support to the HTGR, while also maintaining its cooperative PBR program with FRG.

  10. Comparative evaluation of pebble-bed and prismatic fueled high-temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    A comparative evaluation has been performed of the HTGR and the Federal Republic of Germany's Pebble Bed Reactor (PBR) for potential commercial applications in the US. The evaluation considered two reactor sizes [1000 and 3000 MW(t)] and three process applications (steam cycle, direct cycle, and process heat, with outlet coolant temperatures of 750, 850, and 9500C, respectively). The primary criterion for the comparison was the levelized (15-year) cost of producing electricity or process heat. Emphasis was placed on the cost impact of differences between the prismatic-type HTGR core, which requires periodic refuelings during reactor shutdowns, and the pebble bed PBR core, which is refueled continuously during reactor operations. Detailed studies of key technical issues using reference HTGR and PBR designs revealed that two cost components contributing to the levelized power costs are higher for the PBR: capital costs and operation and maintenance costs. A third cost component, associated with nonavailability penalties, tended to be higher for the PBR except for the process heat application, for which there is a large uncertainty in the HTGR nonavailability penalty at the 9500C outlet coolant temperature. A fourth cost component, fuel cycle costs, is lower for the PBR, but not sufficiently lower to offset the capital cost component. Thus the HTGR appears to be slightly superior to the PBR in economic performance. Because of the advanced development of the HTGR concept, large HTGRs could also be commercialized in the US with lower R and D costs and shorter lead times than could large PBRs. It is recommended that the US gas-cooled thermal reactor program continue giving primary support to the HTGR, while also maintaining its cooperative PBR program with FRG

  11. Tensile strength of ash cake beds at high-temperature conditions

    Energy Technology Data Exchange (ETDEWEB)

    Dockter, B.A.; Hurley, J.P.

    1996-12-31

    The Energy and Environmental Research Center (EERC) is working with Electric Power Research Institute (EPRI) and a consortium of companies in partnership with the US Department of Energy (DOE) to perform the research necessary to determine the factors that cause hot-gas cleanup filters to be blinded by ash or to develop deposits that can bridge the filters and cause them to fail. The primary deliverable will be a graphics-driven computer model that can be used as an engineering tool to help predict ash-related hot-gas filter problems based on analyses of coal and sorbent, as well as system operating parameters. This paper presents preliminary testing data on determining the tensile strengths of coal ash particles at elevated temperatures and simulated combustor gas conditions. The range in temperatures for tensile testing is ambient to 900 C. The simulated gas atmosphere includes carbon dioxide, water vapor, oxygen, sulfur dioxide, sodium chloride, hydrochloric acid, and nitrogen. At present, all testing has been performed using ash from the Westinghouse advanced particle filter (APF) at the American Electric Power Service Corporation (AEP) Tidd pressurized fluidized-bed combustor (PFBC) demonstration plant in Ohio. Other sources of filter ashes, including several from non-American PFBC systems, will also be evaluated.

  12. Loss-of-water accident analysis of the pebble-bed modular high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    The high pressure helium and water/steam are respectively used as the primary and secondary coolant for the pebble-bed modular high temperature gas-cooled reactor (HTGR). Loss-of-water accident is one of the typical design basis accident (DBA), which would be caused by malfunction or current failure of the feed water pump, as well as the false action of the feed water valve. During the loss-of-water accident, due to the loss of the secondary heat sink, the temperature and pressure of primary coolant will increase. Subsequently, the reactor scram will be triggered by the protective signal of the “high flow rate proportion of primary circuit and secondary circuit” or the “high core inlet helium temperature”. For this type of the accident, the earlier open of the safety valve of the primary circuit should be avoided by reactor design. Based on the preliminary design of the 250 MW pebble-bed modular high temperature gas-cooled reactor (HTR-PM), with the coupled analysis code TINTE-BLAST, accidents with different slowdown rate of the feed water supply have been studied. The important parameters, including the reactor power, fuel element temperature, inlet/outlet helium temperature of the core, and especially the primary pressure, are analyzed. The consequences with first scram signal succeeding or failing are compared. The results can prove that, according to the current design of the protection system, this kind of accident can be detected in time. The scram signal will trigger the reactor shut down quickly, without causing the earlier open of the safety valve. After the reactor is successfully shut down, due to the inherent safety feature of the HTGR, the temperature and the pressure in the primary circuit will increase very slowly. The temperature of the fuel element, as well as that of the components, will not exceed the design limitations. (author)

  13. Gas Turbine High Temperature Gas (Helium) Reactor Using Pebble Bed Fuel Derived from Spent Fuel

    International Nuclear Information System (INIS)

    Project goals: Build on the $1B investment spent during the NGNP Project for the only true Inherently Safe Small Modular Reactor Design – the only SMR design that can make this claim due to negative temperature coefficient of reactivity - no containment required – less construction cost. NPMC in Partnership with Pebble Bed Modular Group, a fully owned subsidiary of Eskom, RSA to Factory Build Complete Plant in Modular Sections at Factory Site in Oswego, NY for transport to site by rail or shipping for world wide export. NPMC will provide Project and Construction Management of all new builds from plant sites through construction, commissioning and startup using local labor. License and Construct ion of spent fuel processing facility in both NY and South Africa using Proven Technology. Ultimate goals of project: 1. Award of the 2013 US DOE Innovative SMR $452M cost share grant for US NRC License Certification 2.Build Full Scale Demonstration Plant at Koeburg, RSA with World Bank Funding managed by NPMC in collaboration with our legal firm, Haynes and Boone LLP 3. Take Plant Orders Immediately (10% Down Payment) 4. Form Strategic Alliance with Domestic and/or International Utility

  14. Theoretical and experimental research of natural convection in the core of the high temperature pebble bed reactor

    International Nuclear Information System (INIS)

    The physical model of the developed THERMIX-2D-code for computing thermohydraulic behaviour of the core of high temperature pebble bed reactors is verified by experiments with natural convection flow. Such fluid flow behaviour can be of very high importance for the real reactor in the case of natural heat removal decay. The experiments are performed in a special set up testing-stand with pressures up to 30 bars and temperatures up to 3000C by using air and helium as fluid. In comparison with the experimental data the numerical results show that a good and useful simulation is given by the program. Pure natural convection flow in packed pebble beds is calculated with a very high degree of reliability. The investigation of flow stability demonstrate that radial-symmetric relations are not given temporarily when national convection is overlayed by forced convection flow. In the discussion it is explained when and to what extent the program leds to useful results in such situations. The test of the effective heat conductivity lambdasub(eff) results in an improvement of the lambdasub(eff)-data used so far for temperatures below 13000C. (orig.)

  15. US/FRG joint report on the pebble bed high temperature reactor resource conservation potential and associated fuel cycle costs

    International Nuclear Information System (INIS)

    Independent analyses at ORNL and KFA have led to the general conclusion that the flexibility in design and operation of a high-temperature gas-cooled pebble-bed reactor (PBR) can result in favorable ore utilization and fuel costs in comparison with other reactor types, in particular, with light-water reactors (LWRs). Fuel reprocessign and recycle show considerable promise for reducing ore consumption, and even the PBR throwaway cycle is competitive with fuel recycle in an LWR. The best performance results from the use of highly enriched fuel. Proliferation-resistant measures can be taken using medium-enriched fuel at a modest ore penalty, while use of low-enriched fuel would incur further ore penalty. Breeding is possible but net generation of fuel at a significant rate would be expensive, becoming more feasible as ore costs increase substantially. The 233U inventory for a breeder could be produced by prebreeders using 235U fuel

  16. Pore Scale Thermal Hydraulics Investigations of Molten Salt Cooled Pebble Bed High Temperature Reactor with BCC and FCC Configurations

    Directory of Open Access Journals (Sweden)

    Shixiong Song

    2014-01-01

    CFD results and empirical correlations’ predictions of pressure drop and local Nusselt numbers. Local pebble surface temperature distributions in several default conditions are investigated. Thermal removal capacities of molten salt are confirmed in the case of nominal condition; the pebble surface temperature under the condition of local power distortion shows the tolerance of pebble in extreme neutron dose exposure. The numerical experiments of local pebble insufficient cooling indicate that in the molten salt cooled pebble bed reactor, the pebble surface temperature is not very sensitive to loss of partial coolant. The methods and results of this paper would be useful for optimum designs and safety analysis of molten salt cooled pebble bed reactors.

  17. The pebble bed high temperature reactor as a source of nuclear process heat. Vol. 2

    International Nuclear Information System (INIS)

    A theoretical analysis is given for a series of 8 different variants of the pebble-bed reactor in the 'once through' fuel management scheme. The comparison gives some insight into the parametric sensitivities and into the development potential of this type. The thorium/U-233 recycling fuel cycle allows to increase the conversion ratio up to the range between 0.90 and 0.95. The feasibility for a changeover between different fuel cycles under full power operation. - The study is complemented by a review of the relevant previous investigations. (orig.)

  18. Closed Brayton Cycle power system with a high temperature pellet bed reactor heat source for NEP applications

    Science.gov (United States)

    Juhasz, Albert J.; El-Genk, Mohamed S.; Harper, William B., Jr.

    1992-01-01

    Capitalizing on past and future development of high temperature gas reactor (HTGR) technology, a low mass 15 MWe closed gas turbine cycle power system using a pellet bed reactor heating helium working fluid is proposed for Nuclear Electric Propulsion (NEP) applications. Although the design of this directly coupled system architecture, comprising the reactor/power system/space radiator subsystems, is presented in conceptual form, sufficient detail is included to permit an assessment of overall system performance and mass. Furthermore, an attempt is made to show how tailoring of the main subsystem design characteristics can be utilized to achieve synergistic system level advantages that can lead to improved reliability and enhanced system life while reducing the number of parasitic load driven peripheral subsystems.

  19. Temperature distribution and control in liquefied petroleum gas fluidized beds

    Institute of Scientific and Technical Information of China (English)

    Li Wang; Ping Wu; Yanping Zhang; Jing Yang; Lige Tong

    2004-01-01

    Temperature distribution and control have been investigated in a liquefied petroleum gas (LPG) fluidized bed with hollow corundum spheres (A12O3) of 0.867-1.212 mm in diameter at moderately high temperatures (800-1100℃). Experiments were carried out for the air consumption coefficient α in the range of 0.3 to 1.0 and the fluidization number N in the range of 1.3 to 3.0. Particle properties, initial bed height, α and N all affect temperature distribution in the bed. Bed temperature can be adjusted about 200℃ by combined the adjusting of α and N.

  20. SHOVAV-JUEL. A one dimensional space-time kinetic code for pebble-bed high-temperature reactors with temperature and Xenon feedback

    International Nuclear Information System (INIS)

    The present report describes the modelling basis and the structure of the neutron kinetics-code SHOVAV-Juel. Information for users is given regarding the application of the code and the generation of the input data. SHOVAV-Juel is a one-dimensional space-time-code based on a multigroup diffusion approach for four energy groups and six groups of delayed neutrons. It has been developed for the analysis of the transient behaviour of high temperature reactors with pebble-bed core. The reactor core is modelled by horizontal segments to which different materials compositions can be assigned. The temperature dependence of the reactivity is taken into account by using temperature dependent neutron cross sections. For the simulation of transients in an extended time range the time dependence of the reactivity absorption by Xenon-135 is taken into account. (orig./RW)

  1. Development and application of a high-temperature sampling probe for burning chamber conditions of fluidized-bed combustion; Korkean laempoetilan naeytteenottosondin kehittaeminen ja soveltaminen leijukerrospolton tulipesaeolosuhteisiin

    Energy Technology Data Exchange (ETDEWEB)

    Larjava, K.; Paerkkae, M.; Jormanainen, P.; Roine, J.; Paakkinen, K. [VTT Chemistry, Espoo (Finland); Linna, V. [VTT Energy, Jyvaeskylae (Finland)

    1996-12-01

    A sampling probe for the burning chamber conditions of fluidized-bed combustion will be developed in this project. The probe will be suitable for sampling vaporous heavy and alkali metals and other condensing compounds (e.g. chlorides) as well combustion gases and alternatively also flue gas particles at high temperatures. The knowledge gained with the probe will help understanding, developing and modeling combustion processes and will thus aid the manufacturers of the boilers. (author)

  2. Carbon Dioxide Captured from Flue Gas by Modified Ca-based Sorbents in Fixed-bed Reactor at High Temperature

    Institute of Scientific and Technical Information of China (English)

    YANG Lei; YU Hongbing; WANG Shengqiang; WANG Haowen; ZHOU Qibin

    2013-01-01

    Four kinds of Ca-based sorbents were prepared by calcination and hydration reactions using different precursors: calcium hydroxide,calcium carbonate,calcium acetate monohydrate and calcium oxide.The CO2 absorption capacity of those sorbents was investigated in a fixed-bed reactor in the temperature range of 350 650 ℃.It was found that all of those sorbents showed higher capacity for CO2 absorption when the operating temperature higher than 450 ℃.The CaAc2-CaO sorbent showed the highest CO2 absorption capacity of 299 mg·g-1.The morphology of those sorbents was examined by scanning electron microscope(SEM),and the changes of composition before and after carbonation were also determined by X-ray diffraction(XRD).Results indicated that those sorbents have the similar chemical compositions and crystalline phases before carbonation reaction [mainly Ca(OH)2],and CaCO3 is the main component after carbonation reaction.The SEM morphology shows clearly that the sorbent pores were filled with reaction products after carbonation reaction,and became much denser than before.The N2 adsorption-desorption isotherms indicated that the CaAc2-CaO and CaCO3-CaO sorbents have higher specific surface area,larger pore volume and appropriate pore size distribution than that of CaO-CaO and Ca(OH)2-CaO.

  3. Development and application of a high-temperature sampling probe for burning chamber conditions in fluidized-bed combustion; Korkean laempoetilan naeytteenottosondin kehittaeminen ja soveltaminen leijukerrospolton tulipesaeolosuhteisiin

    Energy Technology Data Exchange (ETDEWEB)

    Larjava, K.; Paerkkae, M. [VTT Chemical Technology, Espoo (Finland); Linna, V. [VTT Energy, Jyvaeskylae (Finland). Environmental Technology

    1997-10-01

    Determination of heavy and alkali metals and other condensing compounds (e.g. chlorides) in combustion chamber conditions is limited by the poor suitability of traditional methods for sampling at high temperatures. IFRF has developed a high-temperature sampling probe for sampling HCN and NH{sub 3}, which has been tested for sampling of NH{sub 3} by Chalmers University of Technology in Sweden. VTT Chemical Technology and Chalmers University of Technology have in their preliminary experiments determined contents of vaporous heavy metals in the combustion chamber of a 12 MW circulating fluidized-bed boiler using this probe. According to the results, the modified probe is suitable for heavy metal determination in combustion chamber. Based on this series of experiments, modification of the probe has been started on the own financing of VTT Chemical Technology and a field measurement was performed in November 1994 to test the present version of the probe. Based on the results of that measurement, the probe has been modified further on as a part of this LIEKKI 2 project. Similar kind of a principle has been applied in the probe which has been developed by VTT Energy during 1994. The probe is built for determination of gas composition of fluidized bed in full-scale boilers. The purpose of this project is to develop and test a sampling probe for fluidized bed combustion. The main advantage of the probe is that condensation losses in sampling due to high temperature gradients can be avoided. Thus, the probe is very suitable for sampling vaporous heavy and alkali metals and other condensing species as well as burning gases and alternatively also solids at high temperatures

  4. Thorium–based fuel cycles : saving uranium in a 200 MWth pebble bed high temperature reactor / S.K. Gintner

    OpenAIRE

    Gintner, Stephan Konrad

    2010-01-01

    The predominant nuclear fuel used globally at present is uranium which is a finite resource. Thorium has been identified as an alternative nuclear fuel source that can be utilized in almost all existing uranium–based reactors and can significantly help in conserving limited uranium reserves. Furthermore, the elimination of proliferation risks associated with thorium–based fuel cycles is a key reason for re–evaluating the possible utilization of thorium in high temperature reactors. In additio...

  5. The pebble-bed high-temperature reactor as a source of nuclear process heat. Vol. 4

    International Nuclear Information System (INIS)

    In this volume the design conditions for a helium-heated steam reformer in the primary circuit of a high-temperature reactor are explained as far as today's knowledge allows. For the realization of helium-heated steam reformers, some fundamental questions at first occur regarding the heating temperature, heat fluxes, suitable materials and design solutions for steam reformers. It is shown that following the development program carried out until now, solutions to these questions can be seen. Moreover, details are given about the heat transfer, the mechanical design and the behaviour of reformer materials in helium with regard to H2- and T-permeation as well as corrosion. Furthermore, questions about the choice of the lay-out data, the design form, the arrangement in the helium circuits of the nuclear reactor and the necessary development steps are handled. Some design examples of heat exchangers for a 3,000 MW(th)-plant are given, too. (orig.)

  6. User's manual for ASTERIX-2: A two-dimensional modular code system for the steady state and xenon transient analysis of a pebble bed high temperature reactor

    International Nuclear Information System (INIS)

    The ASTERIX modular code package was developed at KFA Laboratory-Juelich for the steady state and xenon transient analysis of a pebble bed high temperature reactor. The code package was implemented on the Stanford Linear Accelerator Center Computer in August, 1980, and a user's manual for the current version of the code, identified as ASTERIX-2, was prepared as a cooperative effort by KFA Laboratory and GE-ARSD. The material in the manual includes the requirements for accessing the program, a description of the major subroutines, a listing of the input options, and a listing of the input data for a sample problem. The material is provided in sufficient detail for the user to carry out a wide range of analysis from steady state operations to the xenon induced power transients in which the local xenon, temperature, buckling and control feedback effects have been incorporated in the problem solution. (orig.)

  7. Parametric study of thorium fuel cycles in a 100MWth pebble bed high temperature reactor / F. Panday

    OpenAIRE

    Panday, Farisha

    2011-01-01

    The current project was conducted in order to select an optimized open Thorium/Uranium fuel cycle for the Pebble Bed Modular Reactor (PBMR) concept in motivation for the 100MWth PBMR Power Plant. A sensitivity study on the heavy metal loading of the fuel sphere was performed to accomplish this task. The effect on various parameters was evaluated to determine the influence of varying the Heavy Metal (HM) from 6 gHM/sphere to 20 gHM/sphere and at different feed fuel enrichment...

  8. Numerical Studies of the Gas-Solid Hydrodynamics at High Temperature in the Riser of a Bench-Scale Circulating Fluidized Bed

    Directory of Open Access Journals (Sweden)

    Maximilian J. Hodapp

    2012-01-01

    Full Text Available The hydrodynamics of circulating fluidized beds (CFBs is a complex phenomenon that can drastically vary depending on operational setup and geometrical configuration. A research of the literature shows that studies for the prediction of key variables in CFB systems operating at high temperature still need to be implemented aiming at applications in energy conversion, such as combustion, gasification, or fast pyrolysis of solid fuels. In this work the computational fluid dynamics (CFD technique was used for modeling and simulation of the hydrodynamics of a preheating gas-solid flow in a cylindrical bed section. For the CFD simulations, the two-fluid approach was used to represent the gas-solid flow with the k-epsilon turbulence model being applied for the gas phase and the kinetic theory of granular flow (KTGF for the properties of the dispersed phase. The information obtained from a semiempirical model was used to implement the initial condition of the simulation. The CFD results were in accordance with experimental data obtained from a bench-scale CFB system and from predictions of the semiempirical model. The initial condition applied in this work was shown to be a viable alternative to a more common constant solid mass flux boundary condition.

  9. Analytical Solution of Fick's Law of the TRISO-Coated Fuel Particles and Fuel Elements in Pebble-Bed High Temperature Gas-Cooled Reactors

    International Nuclear Information System (INIS)

    Two kinds of approaches are built to solve the fission products diffusion models (Fick's equation) based on sphere fuel particles and sphere fuel elements exactly. Two models for homogenous TRISO-coated fuel particles and fuel elements used in pebble-bed high temperature gas-cooled reactors are presented, respectively. The analytical solution of Fick's equation for fission products diffusion in fuel particles is derived by variables separation. In the fuel element system, a modification of the diffusion coefficient from D to D/r is made to characterize the difference of diffusion rates in distinct areas and it is shown that the Laplace and Hankel transformations are effective as the diffusion coefficient in Fick's equation is dependant on the radius of the fuel element. Both the solutions are useful for the prediction of the fission product behaviors and could be programmed in the corresponding engineering calculations. (general)

  10. Analytical solution of Fick's law of the TRISO-coated fuel particles and fuel elements in pebble-bed high temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    Two kinds of approaches are built to solve the fission products diffusion models (Fick's equation) based on sphere fuel particles and sphere fuel elements exactly. Two models for homogenous TRISO-coated fuel particles and fuel elements used in pebble-bed high temperature gas-cooled reactors are presented, respectively. The analytical solution of Fick's equation for fission products diffusion in fuel particles is derived by variables separation. In the fuel element system, a modification of the diffusion coefficient from D to D/r is made to characterize the difference of diffusion rates in distinct areas and it is shown that the Laplace and Hankel transformations are effective as the diffusion coefficient in Fick's equation is dependant on the radius of the fuel element. Both the solutions are useful for the prediction of the fission product behaviors and could be programmed in the corresponding engineering calculations. (authors)

  11. Analytical Solution of Fick's Law of the TRISO-Coated Fuel Particles and Fuel Elements in Pebble-Bed High Temperature Gas-Cooled Reactors

    Institute of Scientific and Technical Information of China (English)

    CAO Jian-Zhu; FANG Chao; SUN Li-Feng

    2011-01-01

    T wo kinds of approaches are built to solve the fission products diffusion models (Fick's equation) based on sphere fuel particles and sphere fuel elements exactly. Two models for homogenous TRISO-coated fuel particles and fuel elements used in pebble-bed high temperature gas-cooled reactors are presented, respectively. The analytica,solution of Fick's equation for fission products diffusion in fuel particles is derived by variables separation.In the fuel element system, a modification of the diffusion coefficient from D to D/r is made to characterize the difference of diffusion rates in distinct areas and it is shown that the Laplace and Hankel transformations are effective as the diffusion coefficient in Fick's equation is dependant on the radius of the fuel element. Both the solutions are useful for the prediction of the fission product behaviors and could be programmed in the corresponding engineering calculations.%@@ Two kinds of approaches are built to solve the fission products diffusion models(Fick's equation) based on sphere fuel particles and sphere fuel elements exactly.Two models for homogenous TRISO-coated fuel particles and fuel elements used in pebble-bed high temperature gas-cooled reactors are presented,respectively.The analytical solution of Fick's equation for fission products diffusion in fuel particles is derived by variables separation.In the fuel element system,a modification of the diffusion coefficient from D to D/r is made to characterize the difference of diffusion rates in distinct areas and it is shown that the Laplace and Hankel transformations are effective as the diffusion coefficient in Fick's equation is dependant on the radius of the fuel element.Both the solutions are useful for the prediction of the fission product behaviors and could be programmed in the corresponding engineering calculations.

  12. One-dimensional modeling of radial heat removal during depressurized heatup transients in modular pebble-bed and prismatic high temperature gas-cooled reactors

    International Nuclear Information System (INIS)

    A one-dimensional computational model was developed to evaluate the heat removal capabilities of both prismatic-core and pebble-bed modular HTGRs during depressurized heatup transients. A correlation was incorporated to calculate the temperature- and neutron-fluence-dependent thermal conductivity of graphite. The modified Zehner-Schluender model was used to determine the effective thermal conductivity of a pebble bed, accounting for both conduction and radiation. Studies were performed for prismatic-core and pebble-bed modular HTGRs, and the results were compared to analyses performed by GA and GR, respectively. For the particular modular reactor design studied, the prismatic HTGR peak temperature was 2152.20C at 38 hours following the transient initiation, and the pebble-bed peak temperature was 1647.80C at 26 hours. These results compared favorably with those of GA and GE, with only slight differences caused by neglecting axial heat transfer in a one-dimensional radial model. This study found that the magnitude of the initial power density had a greater effect on the temperature excursion than did the initial temperature

  13. Comparison of electron beam and laser beam powder bed fusion additive manufacturing process for high temperature turbine component materials

    Energy Technology Data Exchange (ETDEWEB)

    Dryepondt, Sebastien N [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Pint, Bruce A [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Ryan, Daniel [Solar Turbines, Inc., San Diego, CA (United States)

    2016-04-01

    The evolving 3D printer technology is now at the point where some turbine components could be additive manufactured (AM) for both development and production purposes. However, this will require a significant evaluation program to qualify the process and components to meet current design and quality standards. The goal of the project was to begin characterization of the microstructure and mechanical properties of Nickel Alloy X (Ni-22Cr-18Fe-9Mo) test bars fabricated by powder bed fusion (PBF) AM processes that use either an electron beam (EB) or laser beam (LB) power source. The AM materials produced with the EB and LB processes displayed significant differences in microstructure and resultant mechanical properties. Accordingly, during the design analysis of AM turbine components, the specific mechanical behavior of the material produced with the selected AM process should be considered. Comparison of the mechanical properties of both the EB and LB materials to those of conventionally processed Nickel Alloy X materials indicates the subject AM materials are viable alternatives for manufacture of some turbine components.

  14. Characterization of constrained beryllium pebble beds after neutron irradiation at HFR at high temperatures up to helium production of 3000 appm

    Energy Technology Data Exchange (ETDEWEB)

    Chakin, V., E-mail: vladimir.chakin@kit.edu [Institute for Applied Materials – Applied Materials Physics, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Plarz 1, 76344 Eggenstein-Leopoldshafen (Germany); Rolli, R. [Institute for Applied Materials – Materials and Biomechanics, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Plarz 1, 76344 Eggenstein-Leopoldshafen (Germany); Moeslang, A.; Vladimirov, P.; Kurinskiy, P. [Institute for Applied Materials – Applied Materials Physics, Karlsruhe Institute of Technology, Hermann-von-Helmholtz-Plarz 1, 76344 Eggenstein-Leopoldshafen (Germany); Til, S. van; Magielsen, A.J. [Nuclear Research and Consultancy Group, Westerduinweg 3, Postbus 25, 1755 ZG Petten (Netherlands); Zmitko, M. [The European Joint Undertaking for ITER and the Development of Fusion Energy, c/ Josep Pla, no. 2, Torres Diagonal Litoral, Edificio B3, 08019 Barcelona (Spain)

    2013-10-15

    Highlights: • Defragmentation of beryllium pebbles at irradiation temperatures of 873 and 948 K was detected. • Formation of brittle beryllium oxide layers on neutron irradiated beryllium pebbles was detected. • Strong interaction between beryllium pebbles and platinum foil under neutron irradiation was detected. • Strong interaction between beryllium pebbles and austenitic stainless steel under neutron irradiation was detected. -- Abstract: Small constrained beryllium pebble beds as well as unconstrained beryllium pebbles have been irradiated within HIDOBE-01 experiment at HFR, Petten, the Netherlands. Beryllium pebbles with 1 mm diameter produced by Rotating Electrode Method (REM) were investigated after irradiation at 630, 740, 873, and 948 K up to helium production of 3000 appm. Intensive pore and bubble formation occurs in beryllium after 873 K irradiation. In the contact zones of the pebbles enhanced pore formation takes place. Oxidation of beryllium pebble external surfaces is accompanied by partial destruction of oxide layers owing to their high brittleness. Strong interactions between beryllium pebbles and platinum foil, as well as between beryllium and stainless steel at contact zones occur at 873 and 948 K.

  15. Feasibility study - Lowered bed temperature in Fluidised Bed boilers for waste; Foerstudie - Saenkt baeddtemperatur i FB-pannor foer avfallsfoerbraenning

    Energy Technology Data Exchange (ETDEWEB)

    Niklasson, Fredrik

    2009-01-15

    Waste incineration generally serves two purposes; 1) dispose of waste and 2) generation of heat and power. In the process of power production from waste fuels, the steam temperatures in super heaters are generally limited by the severe fouling and corrosion that occurs at elevated material temperatures, caused by high concentrations of alkali metals and chloride in the flue gas and fly ash. The overall aim of a continuation of present project is to determine if a reduced temperature of the bed zone in a fluidized bed waste incinerator reduces the amount of alkali chlorides in the flue gas. If so, a reduced bed temperature might enable increased steam temperature in super heaters, or, at unchanged steam temperature, improve the lifespan of the super heaters. The results from the project are of interest for plant owners wishing to improve performance of existing plants. The results may also be used to modify the design of future plants by boiler manufacturers. The aim of present pre-study was to determine how far the bed temperature can be reduced in a waste fired fluidized bed boiler in Boraas while maintaining a stable operation with sufficient combustion temperature in the freeboard to fulfil the directives of waste incineration. A continuation of the project will be based on the results from present study. The work is based on experiments at the test boiler. During the present study, no other measurements were performed apart from some sampling of bed material and ashes at different modes of operation. The experiments show that it is possible to alter the air and recycled flue gas in such a manner that the bed temperature is reduced from about 870 deg C to 700 deg C at 100% load and normal fuel mixture, while fulfilling the directive of 850 deg C at 2 seconds. Within normal variations of the fuel properties, however, the bed temperature increases to somewhat above 700 deg C if the fuel turns dry, while it falls below 650 deg C when the fuel turns wet. With

  16. High power density reactors based on direct cooled particle beds

    Science.gov (United States)

    Powell, J. R.; Horn, F. L.

    Reactors based on direct cooled High Temperature Gas Cooled Reactor (HTGR) type particle fuel are described. The small diameter particle fuel is packed between concentric porous cylinders to make annular fuel elements, with the inlet coolant gas flowing inwards. Hot exit gas flows out along the central channel of each element. Because of the very large heat transfer area in the packed beds, power densities in particle bed reactors (PBRs) are extremely high resulting in compact, lightweight systems. Coolant exit temperatures are high, because of the ceramic fuel temperature capabilities, and the reactors can be ramped to full power and temperature very rapidly. PBR systems can generate very high burst power levels using open cycle hydrogen coolant, or high continuous powers using closed cycle helium coolant. PBR technology is described and development requirements assessed.

  17. Behavior of Alkali Metals and Ash in a Low-Temperature Circulating Fluidized Bed (LTCFB) Gasifier

    DEFF Research Database (Denmark)

    Narayan, Vikas; Jensen, Peter Arendt; Henriksen, Ulrik Birk;

    2016-01-01

    , the low reactor temperature ensures that high-alkali biomass fuels canbe used without risk of bed defluidization. This paper presents the first investigation of the fate of alkali metals and ash in lowtemperaturegasifiers. Measurements on bed material and product gas dust samples were made on a 100 k......A low-temperature circulating fluidized bed system (LTCFB) gasifier allows for pyrolysis and gasification to occurat low temperatures, thereby improving the retention of alkali and other inorganic elements within the system and minimizingthe amount of ash species in the product gas. In addition...

  18. 球床高温气冷堆闭式循环特性%Characteristics of closed fuel cycles in the pebble bed high temperature gas cooled reactor

    Institute of Scientific and Technical Information of China (English)

    位金锋; 孙玉良; 李富

    2012-01-01

    The reuse of uranium and plutonium from high temperature gas-cooled reactor(HTGR) spent fuel will improve resource usage and minimize waste.The characteristics of different closed fuel cycles were studied here for uranium and plutonium recycled from 250 MWth high-temperature gas-cooled reactor pebble-bed-module(HTR-PM) spent fuel from a U-Pu fueled core.PuO2 and MOX fuel elements using recycled plutonium and uranium were then used in new PuO2 or MOX fueled cores with the same geometry as the original reactor.PuO2 from LWR spent fuel was also evaluated.The characteristics of the fuel utilization and transuranic incineration in these closed fuel cycles were studied with the VSOP program.The natural uranium utilization closed fuel for these closed fuel cycle is increased by 6%,8% and 20%,while the plutonium burn rates are 40%,41% and 63%,respectively.Thus,these HTGR closed fuel cycles can effectively burn plutonium isotopes and increase natural uranium utilization.%从提高天然铀利用率和改进废物管理方面考虑,研究球床高温气冷堆乏燃料中铀钚的再利用和不同闭式燃料循环的特性。在250MW热功率球床模块式高温气冷堆示范电站铀钚循环的乏燃料中提取铀和钚为核燃料,设计了PuO2和混合氧化物(MOX)燃料元件,将新设计的燃料元件重新装入与示范电站有同样结构和尺寸的堆芯,分别形成纯钚燃料循环和MOX燃料循环。还研究了基于轻水堆级钚的燃料循环。采用了高温气冷堆物理设计程序VSOP,研究了高温气冷堆不同闭式循环的燃料利用和超铀元素焚烧特性。不同闭式循环钚消耗率分别为50%、46%和71%,天然铀的电利用率分别提高了6%、8%和20%。结果表明:高温气冷堆闭式燃料循环能有效焚烧钚同位素,适度提高天然铀的利用率。

  19. COPROX fixed bed reactor - temperature control schemes

    Energy Technology Data Exchange (ETDEWEB)

    Giunta, P.; Moreno, M.; Marino, F.; Amadeo, N.; Lobarde, M. [Laboratorio de Procesos Cataliticos, Facultad de Ingenieria, Universidad de Buenos Aires, Buenos Aires (Argentina)

    2012-06-15

    Different temperature control schemes for the COPROX stage of a 5-kW fuel cell system were analyzed. It was found that, among the schemes proposed, i.e., co- and countercurrent heat exchange, single adiabatic reactor and series of adiabatic reactors with interstage heat exchange, the best choice for temperature control was the series of adiabatic reactors with interstage heat exchange. This scheme represented the best way to keep the average temperature around 443 K, which was found to be the most suitable temperature for selectivity towards CO oxidation. If hydrogen is produced from ethanol steam reforming, the heat withdrawal can be carried out by the water/ethanol reformer feed mixture, thus contributing to the energy integration of the overall system. (Copyright copyright 2012 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim)

  20. The impact of bed temperature on heat transfer characteristic between fluidized bed and vertical rifled tubes

    Science.gov (United States)

    Blaszczuk, Artur; Nowak, Wojciech

    2016-10-01

    In the present work, the heat transfer study focuses on assessment of the impact of bed temperature on the local heat transfer characteristic between a fluidized bed and vertical rifled tubes (38mm-O.D.) in a commercial circulating fluidized bed (CFB) boiler. Heat transfer behavior in a 1296t/h supercritical CFB furnace has been analyzed for Geldart B particle with Sauter mean diameter of 0.219 and 0.246mm. The heat transfer experiments were conducted for the active heat transfer surface in the form of membrane tube with a longitudinal fin at the tube crest under the normal operating conditions of CFB boiler. A heat transfer analysis of CFB boiler with detailed consideration of the bed-to-wall heat transfer coefficient and the contribution of heat transfer mechanisms inside furnace chamber were investigated using mechanistic heat transfer model based on cluster renewal approach. The predicted values of heat transfer coefficient are compared with empirical correlation for CFB units in large-scale.

  1. Temperature and Time Requirements for Controlling Bed Bugs (Cimex lectularius under Commercial Heat Treatment Conditions

    Directory of Open Access Journals (Sweden)

    Stephen A. Kells

    2011-08-01

    Full Text Available Developing effective alternative approaches for disinfesting bed bugs from residential spaces requires a balance between obtaining complete insect mortality, while minimizing costs and energy consumption. One method of disinfestation is the application of lethal high temperatures directly to rooms and contents within a structure (termed whole-room heat treatments. However, temperature and time parameters for efficacy in whole-room heat treatments are unknown given the slower rate of temperature increase and the probable variability of end-point temperatures within a treated room. The objective of these experiments was to explore requirements to produce maximum mortality from heat exposure using conditions that are more characteristic of whole-room heat treatments. Bed bugs were exposed in an acute lethal temperature (LTemp trial, or time trials at sub-acute lethal temperatures (LTime. The lethal temperature (LTemp99 for adults was 48.3 °C, while LTemp99 for eggs was 54.8 °C. Adult bed bugs exposed to 45 °C had a LTime99 of 94.8 min, while eggs survived 7 h at 45 °C and only 71.5 min at 48 °C. We discuss differences in exposure methodologies, potential reasons why bed bugs can withstand higher temperatures and future directions for research.

  2. Modelling of HTR (High Temperature Reactor Pebble-Bed 10 MW to Determine Criticality as A Variations of Enrichment and Radius of the Fuel (Kernel With the Monte Carlo Code MCNP4C

    Directory of Open Access Journals (Sweden)

    Hammam Oktajianto

    2014-12-01

    Full Text Available Gas-cooled nuclear reactor is a Generation IV reactor which has been receiving significant attention due to many desired characteristics such as inherent safety, modularity, relatively low cost, short construction period, and easy financing. High temperature reactor (HTR pebble-bed as one of type of gas-cooled reactor concept is getting attention. In HTR pebble-bed design, radius and enrichment of the fuel kernel are the key parameter that can be chosen freely to determine the desired value of criticality. This paper models HTR pebble-bed 10 MW and determines an effective of enrichment and radius of the fuel (Kernel to get criticality value of reactor. The TRISO particle coated fuel particle which was modelled explicitly and distributed in the fuelled region of the fuel pebbles using a Simple-Cubic (SC lattice. The pebble-bed balls and moderator balls distributed in the core zone using a Body-Centred Cubic lattice with assumption of a fresh fuel by the fuel enrichment was 7-17% at 1% range and the size of the fuel radius was 175-300 µm at 25 µm ranges. The geometrical model of the full reactor is obtained by using lattice and universe facilities provided by MCNP4C. The details of model are discussed with necessary simplifications. Criticality calculations were conducted by Monte Carlo transport code MCNP4C and continuous energy nuclear data library ENDF/B-VI. From calculation results can be concluded that an effective of enrichment and radius of fuel (Kernel to achieve a critical condition was the enrichment of 15-17% at a radius of 200 µm, the enrichment of 13-17% at a radius of 225 µm, the enrichments of 12-15% at radius of 250 µm, the enrichments of 11-14% at a radius of 275 µm and the enrichment of 10-13% at a radius of 300 µm, so that the effective of enrichments and radii of fuel (Kernel can be considered in the HTR 10 MW. Keywords—MCNP4C, HTR, enrichment, radius, criticality 

  3. 球床式高温气冷堆的余热不确定性分析%Uncertainty Analysis on Decay Heat of Pebble-bed High Temperature Gas-cooled Reactor

    Institute of Scientific and Technical Information of China (English)

    贠相羽; 郑艳华; 经荥清; 李富

    2013-01-01

    反应堆在停堆后相当长时间内仍具有较高的剩余发热是核电站的重要特性,也是核电站安全分析的关键.因此,对反应堆余热及其不确定性进行分析,对于合理设计余热排出系统、研究论证燃料元件在事故后的安全特性等均具有重要意义.本工作结合德国针对球床式高温气冷堆制定的余热计算标准,介绍了球床式高温气冷堆剩余发热及其不确定性的计算方法,并结合200 MWe球床模块式高温气冷堆示范工程(HTR-PM)的初步物理设计,对长期运行在满功率平衡堆芯状态下的反应堆停堆后的余热及其不确定性进行了计算分析,为进一步的事故分析提供依据.%The large amount of decay heat in a quite long time after reactor shutdown,which is an important characteristic of the nuclear power plants,should be considered seriously during the safety analysis.Therefore,the study on the decay heat and its uncertainty analysis play an important role in the design of decay heat removal system,as well as in the safety verification of the fuel element during the accident.In referenced to the standard of Germany entitled "Decay Heat Power in Nuclear Fuels of Hightemperature Reactors with Spherical Fuel Elements" especially for pebble-bed high temperature gas-cooled reactor (HTGR),the calculation method of decay heat and its uncertainty of pebble-bed HTGR were introduced.On the basis of the preliminary physical design of Chinese 200 MWe high temperature gas-cooled reactor pebble-bed module (HTR-PM),the decay heat and its uncertainty after reactor shutdown from long-term operation at rated power were analyzed,so as to provide a basis for further accident analysis.

  4. High Temperature Materials Laboratory

    Data.gov (United States)

    Federal Laboratory Consortium — The High Temperature Materials Lab provides the Navy and industry with affordable high temperature materials for advanced propulsion systems. Asset List: Arc Melter...

  5. High temperature furnace

    Science.gov (United States)

    Borkowski, Casimer J.

    1976-08-03

    A high temperature furnace for use above 2000.degree.C is provided that features fast initial heating and low power consumption at the operating temperature. The cathode is initially heated by joule heating followed by electron emission heating at the operating temperature. The cathode is designed for routine large temperature excursions without being subjected to high thermal stresses. A further characteristic of the device is the elimination of any ceramic components from the high temperature zone of the furnace.

  6. HIGH TEMPERATURE DISPLACEMENT SENSOR

    Institute of Scientific and Technical Information of China (English)

    Xu Longxiang; Zhang Jinyu; Schweitzer Gerhard

    2005-01-01

    A high temperature displacement sensor based on the principle of eddy-current is investigated. A new temperature compensation technique by using eddy-current effect is presented to satisfy the special requirement at high temperature up to 550℃. The experiment shows that the temperature compensation technique leads to good temperature stability for the sensors. The variation of the sensitivity as well as the temperature drift of the sensor with temperature compensation technique is only about 7.4% and 90~350 mV at 550℃ compared with that at room temperature, and that of the sensor without temperature compensation technique is about 31.2% and 2~3 V at 550℃ compared with that at room temperature. A new dynamic calibration method for the eddy-current displacement sensor is presented, which is very easy to be realized especially in high frequency and at high temperatures. The high temperature displacement sensors developed are successfully used at temperature up to 550℃ in a magnetic bearing system for more than 100 h.

  7. FLUIDIZED BED STEAM REFORMING ENABLING ORGANIC HIGH LEVEL WASTE DISPOSAL

    International Nuclear Information System (INIS)

    Waste streams planned for generation by the Global Nuclear Energy Partnership (GNEP) and existing radioactive High Level Waste (HLW) streams containing organic compounds such as the Tank 48H waste stream at Savannah River Site have completed simulant and radioactive testing, respectfully, by Savannah River National Laboratory (SRNL). GNEP waste streams will include up to 53 wt% organic compounds and nitrates up to 56 wt%. Decomposition of high nitrate streams requires reducing conditions, e.g. provided by organic additives such as sugar or coal, to reduce NOX in the off-gas to N2 to meet Clean Air Act (CAA) standards during processing. Thus, organics will be present during the waste form stabilization process regardless of the GNEP processes utilized and exists in some of the high level radioactive waste tanks at Savannah River Site and Hanford Tank Farms, e.g. organics in the feed or organics used for nitrate destruction. Waste streams containing high organic concentrations cannot be stabilized with the existing HLW Best Developed Available Technology (BDAT) which is HLW vitrification (HLVIT) unless the organics are removed by pretreatment. The alternative waste stabilization pretreatment process of Fluidized Bed Steam Reforming (FBSR) operates at moderate temperatures (650-750 C) compared to vitrification (1150-1300 C). The FBSR process has been demonstrated on GNEP simulated waste and radioactive waste containing high organics from Tank 48H to convert organics to CAA compliant gases, create no secondary liquid waste streams and create a stable mineral waste form

  8. FLUIDIZED BED STEAM REFORMING ENABLING ORGANIC HIGH LEVEL WASTE DISPOSAL

    Energy Technology Data Exchange (ETDEWEB)

    Williams, M

    2008-05-09

    Waste streams planned for generation by the Global Nuclear Energy Partnership (GNEP) and existing radioactive High Level Waste (HLW) streams containing organic compounds such as the Tank 48H waste stream at Savannah River Site have completed simulant and radioactive testing, respectfully, by Savannah River National Laboratory (SRNL). GNEP waste streams will include up to 53 wt% organic compounds and nitrates up to 56 wt%. Decomposition of high nitrate streams requires reducing conditions, e.g. provided by organic additives such as sugar or coal, to reduce NOX in the off-gas to N2 to meet Clean Air Act (CAA) standards during processing. Thus, organics will be present during the waste form stabilization process regardless of the GNEP processes utilized and exists in some of the high level radioactive waste tanks at Savannah River Site and Hanford Tank Farms, e.g. organics in the feed or organics used for nitrate destruction. Waste streams containing high organic concentrations cannot be stabilized with the existing HLW Best Developed Available Technology (BDAT) which is HLW vitrification (HLVIT) unless the organics are removed by pretreatment. The alternative waste stabilization pretreatment process of Fluidized Bed Steam Reforming (FBSR) operates at moderate temperatures (650-750 C) compared to vitrification (1150-1300 C). The FBSR process has been demonstrated on GNEP simulated waste and radioactive waste containing high organics from Tank 48H to convert organics to CAA compliant gases, create no secondary liquid waste streams and create a stable mineral waste form.

  9. High temperature superconductivity

    International Nuclear Information System (INIS)

    New superconducting oxides and physical basis of the high-temperature superconductivity developed from 1979 till 1986 are reviewed. The analysis is based upon the concept of exchange amplification of electron-phonon interaction put forward by the author in 1964. Using the high-temperature superconductivity theory an approach to increasing the critical temperature of high-temperature superconductors (HTSC) is proposed along with the means for synthesis of HTSC with higher critical fields. The feasibility of HTSC implementation in the modern physical experiment technology is also considered, e.g. for detecting the magnetic monopoles. 35 refs.; 2 figs

  10. 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 using SOECs is competitive to H-2 production from fossil fuels at electricity prices below 0.02-0.03 is an element of per kWh. Though promising SOEC results on H-2 production have been reported a substantial R&D is still required to obtain inexpensive, high performing and long-term stable...

  11. High Power Fiber Laser Test Bed

    Data.gov (United States)

    Federal Laboratory Consortium — This facility, unique within DoD, power-combines numerous cutting-edge fiber-coupled laser diode modules (FCLDM) to integrate pumping of high power rare earth-doped...

  12. Effects of high salinity wastewater on methanogenic sludge bed systems

    NARCIS (Netherlands)

    Ismail, S.; Gonzalez-Contreras, P.A.; Jeison, D.A.; Lier, van J.B.

    2008-01-01

    The attainable loading potentials of anaerobic sludge bed systems are strongly dependent on the growth of granular biomass with a particular wastewater. Experiments were conducted to determine the effects of high salinity wastewater on the biological and physical properties of methanogenic sludge. S

  13. High-temperature superconductors

    CERN Document Server

    Saxena, Ajay Kumar

    2010-01-01

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

  14. High-temperature electronics

    Science.gov (United States)

    Matus, Lawrence G.; Seng, Gary T.

    1990-02-01

    To meet the needs of the aerospace propulsion and space power communities, the high temperature electronics program at the Lewis Research Center is developing silicon carbide (SiC) as a high temperature semiconductor material. This program supports a major element of the Center's mission - to perform basic and developmental research aimed at improving aerospace propulsion systems. Research is focused on developing the crystal growth, characterization, and device fabrication technologies necessary to produce a family of SiC devices.

  15. High temperature electronics

    Science.gov (United States)

    Seng, Gary T.

    1991-03-01

    In recent years, the aerospace propulsion and space power communities have acknowledged a growing need for electronic devices that are capable of sustained high-temperature operation. Aeropropulsion applications for high-temperature electronic devices include engine ground test instrumentation such as multiplexers, analog-to-digital converters, and telemetry systems capable of withstanding hot section engine temperatures in excess of 600 C. Uncooled operation of control and condition monitoring systems in advanced supersonic aircraft would subject the electronics to temperatures in excess of 300 C. Similarly, engine-mounted integrated electronic sensors could reach temperatures which exceed 500 C. In addition to aeronautics, there are many other areas that could benefit from the existence of high-temperature electronic devices. Space applications include power electronic devices for space platforms and satellites. Since power electronics require radiators to shed waste heat, electronic devices that operate at higher temperatures would allow a reduction in radiator size. Terrestrial applications include deep-well drilling instrumentation, high power electronics, and nuclear reactor instrumentation and control. To meet the needs of the applications mentioned previously, the high-temperature electronics (HTE) program at the Lewis Research Center is developing silicon carbide (SiC) as a high-temperature semiconductor material. Research is focused on developing the crystal growth, growth modeling, characterization, and device fabrication technologies necessary to produce a family of SiC devices. Interest in SiC has grown dramatically in recent years due to solid advances in the technology. Much research remains to be performed, but SiC appears ready to emerge as a useful semiconductor material.

  16. High Temperature QCD

    CERN Document Server

    Lombardo, M P

    2012-01-01

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

  17. High temperature superconductivity

    International Nuclear Information System (INIS)

    This book covers the proceedings of the 3rd National Meeting on High Temperature Superconductivity Topics includes: Crystal growth of superconductors; thermodynamic stability of superconducting materials; spectroscopy of High Tc Superconductors; synchrotron radiation investigation of superconductors; density state determination; measurements of current density; preparation and characterization of superconductors

  18. High temperature hydraulic seals

    Science.gov (United States)

    Williams, K. R.

    1993-05-01

    This program investigated and evaluated high temperature hydraulic sealing technology, including seals, fluids, and actuator materials. Test limits for fluid pressure and temperature were 8000 psi and 700 F respectively. The original plan to investigate CTFE fluid at 350 F as well as other fluids at higher temperatures was reduced in scope to include only the higher temperature investigation. Seals were obtained from 11 manufacturers. Design requirements including materials, dimensions, clearances, and tolerances were established and test modules were constructed from the detail designs which were produced. Nine piston seals and one rod seal were tested at temperatures ranging from -65 to +600 F and pressures to 6000 psi. Fluid performance under these conditions was evaluated. Details of this activity and results of the effort are summarized in this report.

  19. High-temperature superconductivity

    International Nuclear Information System (INIS)

    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

  20. Incineration of kitchen waste with high nitrogen in vortexing fluidized-bed incinerator and its NO emission characteristics

    Institute of Scientific and Technical Information of China (English)

    Feng Duan; Chiensong Chyang; Jiaruei Wen; Jim Tso

    2013-01-01

    Some municipal solid waste (MSW) can be used as the fuel.Combustion of MSW with high nitrogen content is successfully conducted in a lab-scale vortexing fluidized-bed incinerator (VFBI).Pigskin with 16.5 wt.% nitrogen content was used to simulate the high nitrogen content kitchen waste,and silica sand was used as the bed material.The effects of operating conditions,such as the bed temperature,freeboard temperature,excess oxygen ratio,and static bed height on the CO and NO concentrations at the exit of combustor and cyclone were investigated.The experimental results show that the freeboard temperature is the most important factor for CO emission.The order of operating conditions impact on the NO emission is:(1) excess oxygen ratio; (2) bed temperature; (3)freeboard temperature; and (4) static bed height.Utilizing cyclone can significantly reduce the CO emission concentration when the CO concentration released from the freeboard is higher than 50 ppm.On the other hand,the cyclone has no significant effect on the NO emission.Despite having high nitrogen content,a low conversion from fuel-N to NO was attained.Compared with other types of combustors,VFBI reduces the CO and NO emission concentrations much better when burning MSW with high nitrogen content.

  1. 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

  2. Discrete particle modeling of granular temperature distribution in a bubbling fluidized bed

    Institute of Scientific and Technical Information of China (English)

    Yurong He; Tianyu Wang; Niels Deen; Martin van Sint Annaland; Hans Kuipers; Dongsheng Wen

    2012-01-01

    The discrete hard sphere particle model (DPM) is applied in this work to study numerically the distributions of particle and bubble granular temperatures in a bubbling fluidized bed.The dimensions of the bed and other parameters are set to correspond to those of Müller et al.(2008).Various drag models and operational parameters are investigated to find their influence on particle and bubble granular temperatures.Various inlet superficial gas velocities are used in this work to obtain their effect on flow characteristics.It is found that the superficial gas velocity has the most important effect on granular temperatures including bubble granular temperature,particle translational granular temperature and particle rotational granular temperature.The drag force model affects more seriously the large scale variables such as the bubble granular temperature.Restitution coefficient influences all granular temperatures to some degree.Simulation results are compared with experimental results by Müller et al.(2008) showing reasonable agreement.

  3. Desulfurization at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Panula-Nikkilae, E.; Kurkela, E.; Mojtahedi, W.

    1987-01-01

    Two high-temperature desulfurization methods, furnace injection and gasification-desulfurization are presented. In furnace injection, the efficiency of desulfurization is 50-60%, but this method is applied in energy production plants, where flue gas desulfurization cannot be used. Ca-based sorbents are used as desulfurization material. Factors affecting desulfurization and the effect of injection on the boiler and ash handling are discussed. In energy production based on gasification, very low sulfur emissions can be achieved by conventional low-temperature cleanup. However, high-temperature gas cleaning leads to higher efficiency and can be applied to smaller size classes. Ca-, Fe-, or Zn-based sorbents or mixed metals can be used for desulfurization. Most of the methods under development are based on the use of regenerative sorbents in a cleanup reactor located outside the gasifier. So far, only calcium compounds have been used for desulfurization inside the gasifier.

  4. High temperature niobium alloys

    International Nuclear Information System (INIS)

    Niobium alloys are currently being used in various high temperature applications such as rocket propulsion, turbine engines and lighting systems. This paper presents an overview of the various commercial niobium alloys, including basic manufacturing processes, properties and applications. Current activities for new applications include powder metallurgy, coating development and fabrication of advanced porous structures for lithium cooled heat pipes

  5. High temperature thermometric phosphors

    Science.gov (United States)

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

    1999-03-23

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

  6. Advanced control system for temperature control in the pressurized fluid bed of Escatron Thermal Plant Power; Sistema de Control Avanzado para Control de la Temperatura del Lecho Fluido a Presion de la Central Termica de Escatron

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-07-01

    In the P. F-B. C a small problem appears, particularly in Escatron the bed temperature gradient is very high. Such gradient very occasionally reaches 50 degree centigree in a same plane. With the reduction of bed difference of temperature, the average bed temperature could be increased with the result steam cycle benefit, at the same time combustion gases would go at a higher temperature to the gas turbine, increasing therefore its performance. The SCAP system will allow to face the resolution of the injection of combustible problem and in this manner achieve the homogenization of bed temperature in Escatron PFBC Thermal Power Station. (Author)

  7. Experimental study on temperature profile of fixed - bed gasification of oil-palm fronds

    Science.gov (United States)

    Atnaw, Samson M.; Sulaiman, Shaharin A.; Moni, M. Nazmi Z.

    2012-06-01

    Currently the world's second largest palm oil producer Malaysia produces large amount of oil palm biomass each year. The abundance of the biomass introduces a challenge to utilize them as main feedstock for heat and energy generation. Although some oil palm parts and derivatives like empty fruit bunch and fibre have been commercialized as fuel, less attention has been given to oil palm fronds (OPF). Initial feasibility and characterization studies of OPF showed that it is highly feasible as fuel for gasification to produce high value gaseous fuel or syngas. This paper discusses the experimental gasification attempt carried out on OPF using a 50 kW lab scale downdraft gasifier and its results. The conducted study focused on the temperature distributions within the reactor and the characteristics of the dynamic temperature profile for each temperature zones during operation. OPF feedstock of one cubic inch in individual size with 15% average moisture content was utilized. An average pyrolysis zone temperature of 324°Cand an average oxidation zone temperature of 796°Cwere obtained over a total gasification period of 74 minutes. A maximum oxidation zone temperature of 952°Cwas obtained at 486 lpm inlet air flow rate and 10 kg/hr feedstock consumption rate. Stable bluish flare was produced for more than 70% of the total gasification time. The recorded temperature profiles produced closely similar patterns with the temperature profiles recorded from the gasification of woody materials. Similar temperature profile was obtained comparing the results from OPF gasification with that of woody biomass. Furthermore, the successful ignition of the syngas produced from OPF gasification ascertained that OPF indeed has a higher potential as gasification feedstock. Hence, more detailed studies need to be done for better understanding in exploiting the biomass as a high prospect alternative energy solution. In addition, a study of the effect of initial moisture content of OPF

  8. 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 ...

  9. High temperature superconductors

    CERN Document Server

    Paranthaman, Parans

    2010-01-01

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

  10. Test bed for high-uranium-loaded fuel plates

    Energy Technology Data Exchange (ETDEWEB)

    Senn, R.L.; Martin, M.M.

    1979-01-01

    An irradiation test facility has been designed and built to provide a test bed for irradiating a variety of miniature fuel plates. The objective of these tests is to screen various candidate materials as to their suitability for replacing the fully enriched uranium fuel materials currently used by the world's test and research reactors with a lower enrichment fuel material, without significantly degrading reactor operating characteristics and power levels. The use of low-uranium enrichment (up to 45%) in place of highly-enriched fuel for these reactors would reduce the potential for /sup 235/U diversion.

  11. INTERPARTICLE FORCES IN HIGH TEMPERATURE FLUIDIZATION OF GELDART A PARTICLES

    Institute of Scientific and Technical Information of China (English)

    Heping Cui; Jamal Chaouki

    2004-01-01

    Previous reports and current studies show that fluidization of some Geldart A particles is enhanced by increasing bed temperature. Both the averaged local particle concentration and the particle concentration in the dense phase decrease with increasing bed temperature, at constant superficial gas velocities. However, conventional models fail to predict these changes, because the role of interparticle forces is usually neglected at different bed temperatures.Here, the interparticle forces are analyzed to explore the mechanism of gas-solid fluidization at high temperatures. Indeed, as the temperature increases, the interparticle attractive forces decrease while the interparticle repulsive forces increase. Consequently, fluidization behaviors of some Geldart A particles seem to increasingly shift from typical Geldart A towards B with increasing temperature.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  13. Effect of Temperature in Fluidized Bed Fast Pyrolysis of Biomass: Oil Quality Assessment in Test Units

    NARCIS (Netherlands)

    Westerhof, R.J.M.; Brilman, D.W.F.; Swaaij, van W.P.M.; Kersten, S.R.A.

    2010-01-01

    Pine wood was pyrolyzed in a 1 kg/h fluidized bed fast pyrolysis reactor that allows a residence time of pine wood particles up to 25 min. The reactor temperature was varied between 330 and 580 °C to study the effect on product yields and oil composition. Apart from the physical−chemical analysis, a

  14. Temperature in High Temperature SHPB Experiments

    Institute of Scientific and Technical Information of China (English)

    DENG Zhifang; XIE Ruoze; YAN Yixia; LI Sizhong; HUANG Xicheng

    2008-01-01

    As an experimental technique,it's desired that the temperature in specimen is uniform in high temperature split Hopkinson pressure bar (SHPB) experiments.However,the temperature in specimen decreases and the temperature of bars increases when specimen starts to contact with bars,which induces the nonuniform temperature distribution in specimen,and may result in inaccuracy of experimental results.In this paper,the temperature distributions of specimen and bars in high temperature SHPB experiments were investigated while the specimen was heated alone.Firstly,the temperature history of specimen was measured at different initial temperatures by experiments,then simulation was carried out.Simulation results were consistent with experimental results by adjusting the thermal contact coefficient between specimen and bars.By this way,the thermal contact coefficient and simulation results were validated,and the proper cold contact times of specimen and bars in high temperature SHPB experiments were discussed.Finally,the results were compared with those in references.

  15. High Temperature Aquifer Storage

    Science.gov (United States)

    Ueckert, Martina; Niessner, Reinhard; Baumann, Thomas

    2016-04-01

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

  16. 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...... electrolyte, commonly yttria-stabilised-zirconia (YSZ), with porous fuel and oxygen side electrodes. The electrodes must be both electron and oxide ion conducting, and maximising the active surface area is essential for efficient operation. For the fuel electrode a cermet of nickel and YSZ is often used......, whereas a lanthanum strontium manganite - YSZ mix is utilised for the oxygen electrode. Long term durability and performance are key for commercialisation of SOEC technology. To date, experimental tests of 1000. h on electrolysis stacks operated at low current density have shown little or no degradation...

  17. Bed mixing dryer for high moisture content fuels

    Energy Technology Data Exchange (ETDEWEB)

    Hulkkonen, S.; Heinonen, O. [Imatran Voima Oy, Vantaa (Finland)

    1997-07-01

    A bed mixing dryer is a new fuel drying technology used with fluidized bed combustion. Hot bed material is extracted from the fluidized bed and used directly as a heat source to dry the fuel. Imatran Voima Oy (IVO) in Finland has been developing the bed mixing drying technology since the early 1990s. The first pilot plant was built in 1994 at IVO's Kuusamo peat- and wood-fired power plant. The capacity of the plant is 6 MW of electricity and 20 MW of district heat. In Kuusamo the dryer is connected to a bubbling fluidized bed. Since its commissioning in 1994, the pilot dryer has been used successfully for about 3000 hours during the winter heating seasons. The next application of the bed mixing dryer will be a demonstration project in Orebro in Sweden. The fuel to be dried there is sawdust. (author)

  18. An experimental analysis of bed load transport in gravel-bed braided rivers with high grain Reynolds numbers

    Science.gov (United States)

    De Vincenzo, Annamaria; Brancati, Francesco; Pannone, Marilena

    2016-08-01

    Laboratory experiments were performed with nearly uniform fluvial gravel (D50=9 mm, D10=5 mm and D90=13 mm) to analyse the relationship between stream power and bed load transport rate in gravel-bed braided rivers at high grain Reynolds numbers. The values of the unit-width dimensionless bed-load rate qb* and unit-width dimensionless stream power ω* were evaluated in equilibrium conditions based on ten different experimental runs. Then, they were plotted along with values obtained during particularly representative field studies documented in the literature, and a regression law was derived. For comparison, a regression analysis was performed using the data obtained from laboratory experiments characterized by smaller grain sizes and, therefore, referring to relatively low grain Reynolds numbers. A numerical integration of Exner's equation was performed to reconstruct the local and time-dependent functional dependence of qb* and ω*. The results led to the following conclusions: 1) At equilibrium, the reach-averaged bed load transport rate is related to the reach-averaged stream power by different regression laws at high and low grain Reynolds numbers. Additionally, the transition from bed to suspended load transport is accelerated by low Re*, with the corresponding bed load discharge increasing with stream power at a lower, linear rate. 2) When tested against the gravel laboratory measurements, the high Re* power law derived in the present study performs considerably better than do previous formulas. 3) The longitudinal variability of the section-averaged equilibrium stream power is much more pronounced than that characterizing the bed load rate, at least for high Re*. Thus, the stream power and its local-scale heterogeneity seem to be directly responsible for transverse sediment re-distribution and, ultimately, for the determination of the spatial and temporal scales that characterize the gravel bedforms. 4) Finally, the stochastic interpretation of the wetted

  19. Defluidization in fluidized bed gasifiers using high-alkali content fuels

    DEFF Research Database (Denmark)

    Narayan, Vikas; Jensen, Peter Arendt; Henriksen, Ulrik Birk;

    2016-01-01

    major concern in thermal conversion of biomass encountered in fluidized beds is bed agglomeration, which may result in de-fluidization, leading to unscheduled downtime and additional costs. Biomass fuels, especially herbaceous plants, often contain significant amounts of silicon, potassium...... and calcium, which may form viscous melts that adhere on the surface of the colliding bed particles and bind them to form agglomerates. In this paper, studies were made to understand the behavior of inorganic elements (mainly K, Si and Ca) on agglomeration and de-fluidization of alkali rich bed......-material samples undernon-oxidizing conditions in a bench-scale fluidized bed reactor set up. The de-fluidization studies involved measurements with sand and pure potassium salts (KCl and K2CO3) as well as with bed material samples obtained from a 6 MW Low Temperature Circulating Fluidized Bed (LTCFB) gasifier...

  20. Temperature and time influence on the waste plastics pyrolysis in the fixed bed reactor

    Directory of Open Access Journals (Sweden)

    Papuga Saša V.

    2016-01-01

    Full Text Available Pyrolysis as a technique of chemical recycling of plastic materials is causing an increasing level of interest as an environmentally and economically acceptable option for the processing of waste materials. Studies of these processes are carried out under different experimental conditions, in different types of reactors and with different raw materials, which makes the comparison of different processes and the direct application of process parameters quite complex. This paper presents the results of investigation of the influence of temperature in the range of 450°C to 525°C, on the yield of the process of pyrolysis of waste plastics mixture, composed of 45% polypropylene, 35% low density polyethylene and 25% high density polyethylene. Also, this paper presents results of the investigation of the effect of the reaction, atintervals of 30-90 [min], on the yield of pyrolysis of the mentioned waste plastics mixture. Research was conducted in a fixed bed pilot reactor, which was developed for this purpose. The results of the research show that at a temperature of 500°C, complete conversion of raw materials was achieved, for a period of 45 [min], with a maximum yield of the pyrolysis oil of 32.80%, yield of the gaseous products of 65.75% and the solid remains of 1.46%. Afurther increase of temperature increases the yield of gaseous products, at the expense of reducing the yield of pyrolysis oil. Obtained pyrolysis oil has a high calorific value of 45.96 [MJ/kg], and in this regard has potential applications as an alternative fuel.

  1. High temperature gas reactor

    International Nuclear Information System (INIS)

    The present invention provides a reflector block structure of a high temperature gas reactor in which graphite blocks are not failed even a containing cylinder loaded to a fuel exchanger collides against to secured reflectors upon loading and withdrawing fuel constitutional elements. Namely, a protection plate made of a metal material such as stainless steel is covered on the secured reflector blocks disposed to the upper most step among secured graphite reflector blocks constituting the reactor core. In addition, positioning guide grooves are formed on the protection plate for guiding the containing cylinder loaded to the fuel exchanger to the column of the reactor core constitutional elements. With such a constitution, even if the containing cylinder of fuel exchanger is hoisted down and collided against the inner circumferential edge of the secured reflector blocks due to deviation of the position and the direction upon exchange of fuels, the reflector blocks are not failed since the above-mentioned portion is covered with the metal protection plate. In addition, the positioning guide grooves lead the fuel exchanger to a predetermined column correctly. (I.S.)

  2. High Temperature Thermoelectric Materials

    Science.gov (United States)

    Ioannidou, A. A.; Rull, M.; Martin-Gonzalez, M.; Moure, A.; Jacquot, A.; Niarchos, D.

    2014-07-01

    The use of microwave energy for materials processing has a major potential and real advantages over conventional heating such as (1) time and energy savings, (2) rapid heating rates (volumetric heating vs. conduction), (3) considerably reduced processing time and temperature, (4) fine microstructures and hence improved mechanical properties and better product performance, and (5) finally lower environmental impact. In this study, we investigated the use of microwave-assisted synthesis to synthesize a series of Co1- x Fe x Sb3 using this novel approach, which gave high quality materials with little or no impurities in a fraction of the time needed for conventional synthesis. X-ray diffraction analysis was used to examine the structure and the lattice parameters of the samples, while scanning electron microscopy with energy dispersive x-ray spectroscopy was used to study the morphology of the compounds. The samples were sintered by spark plasma sintering, and the highest ZT of 0.33 was obtained for x = 0.2 at 700 K.

  3. High-Temperature Piezoelectric Sensing

    OpenAIRE

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

    2013-01-01

    Piezoelectric sensing is of increasing interest for high-temperature applications in aerospace, automotive, power plants and material processing due to its low cost, compact sensor size and simple signal conditioning, in comparison with other high-temperature sensing techniques. This paper presented an overview of high-temperature piezoelectric sensing techniques. Firstly, different types of high-temperature piezoelectric single crystals, electrode materials, and their pros and cons are discu...

  4. Humidity and Cage and Bedding Temperatures in Unoccupied Static Mouse Caging after Steam Sterilization

    OpenAIRE

    Ward, Gina M; Cole, Kelly; Faerber, Jennifer; Hankenson, F Claire

    2009-01-01

    Contemporary rodent caging and equipment often are sterilized by steam autoclaves prior to use in facilities. This work assessed the microenvironment of unoccupied static mouse cages after steam sterilization to determine when internal temperatures had cooled to levels appropriate for rodent housing. Polycarbonate static cages containing food and corncob bedding were stacked (10 rows × 7 columns) in duplicate (front and back; n = 140 cages) on a storage truck and autoclaved to 249 °F (121 °C)...

  5. 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

  6. Ultra-High Temperature Gratings

    Institute of Scientific and Technical Information of China (English)

    John Canning; Somnath Bandyopadhyay; Michael Stevenson; Kevin Cook

    2008-01-01

    Regenerated gratings seeded by type-Ⅰ gratings are shown to withstand temperatures beyond 1000 ℃. The method of regeneration offers a new approach to increasing temperature resistance of stable fibre Bragg and other gratings. These ultra-high temperature (UHT) gratings extend the applicability of silicate based components to high temperature applications such as monitoring of smelters and vehicle and aircraft engines to high power fibre lasers.

  7. RESEARCH ON THE INFLUENCE OF TEMPERATURE ON THE ACTIVATION OF SELECTED POROUS MNO2 BEDS

    Directory of Open Access Journals (Sweden)

    Iwona Skoczko

    2016-09-01

    Full Text Available Rising demands concerning water treatment and conservation make it necessary to search for more effective as well as cheap and ecologically safe solutions. During the filtration process quartz sand is replaced by filter materials which also have a strong effect on account of reactions taking place on a bed’s surface. Today’s technologies for groundwater and seepage water treatment in rapid filters make use of oxidation beds. They are able to effectively remove manganese (II and iron (II compounds based on heterogeneous oxidation catalysis. The main catalyst of the manganese removal process in terms of its catalytic oxidation in filtration beds is manganese dioxide. This compound is used as an oxidizing agent in many processes. The research conducted as part of this paper was aimed at creating a product with the qualities similar to a popular Greensand bed protected by patent. The authors tested washed quartz sand varying in granulation which was subject to activation in 10% KMnO4 solution. Grains of quartz sand after covering them with a permanent coat of manganese oxide developed the superficial oxidation layer. While performing the tests, a temperature of the process served as a variable. The beds produced as a result of the experiment enable the removal of iron and manganese from water without prior alkylation. Furthermore, they are an effective method of purifying water of organic pollutants and ammoniacal nitrogen. They function as oxidizing and filtering masses.

  8. 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.

  9. High-temperature piezoelectric sensing.

    Science.gov (United States)

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

    2013-01-01

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

  10. Two stage, low temperature, catalyzed fluidized bed incineration with in situ neutralization for radioactive mixed wastes

    International Nuclear Information System (INIS)

    A two stage, low temperature, catalyzed fluidized bed incineration process is proving successful at incinerating hazardous wastes containing nuclear material. The process operates at 550 degrees C and 650 degrees C in its two stages. Acid gas neutralization takes place in situ using sodium carbonate as a sorbent in the first stage bed. The feed material to the incinerator is hazardous waste-as defined by the Resource Conservation and Recovery Act-mixed with radioactive materials. The radioactive materials are plutonium, uranium, and americium that are byproducts of nuclear weapons production. Despite its low temperature operation, this system successfully destroyed poly-chlorinated biphenyls at a 99.99992% destruction and removal efficiency. Radionuclides and volatile heavy metals leave the fluidized beds and enter the air pollution control system in minimal amounts. Recently collected modeling and experimental data show the process minimizes dioxin and furan production. The report also discusses air pollution, ash solidification, and other data collected from pilot- and demonstration-scale testing. The testing took place at Rocky Flats Environmental Technology Site, a US Department of Energy facility, in the 1970s, 1980s, and 1990s

  11. Temperature transients of a fusion-fission ITER pebble bed reactor in loss of coolant accident

    International Nuclear Information System (INIS)

    In this preliminary scoping study, post-accident temperature transients of several fusion-fission designs utilizing ITER-FEAT-like parameters and fission pebble bed fuel technology are examined using a 1-D cylindrical MATLAB heat transfer code along with conventional fission decay heat approximations. Scenarios studied include systems with no additional passive safety features to systems with melting reflectors designed to increase emissivity after reaching a specified temperature. Results show that for a total fission power of ∼1400-2800 MW, two of the realistic variants investigated are passively safe. The crucial time, defined as the time when either any structural part of the fusion-fission tokamak reaches melting point, or when the pebble fuel reaches 1873 K, ranges from 5.7 to 76 h for the unsafe configurations. Additionally, it is illustrated that, fundamentally, the LOCA characteristics of pure fission pebble beds and fusion-fission pebble beds are different. Namely, the former depends on the pebble fuel's large thermal capacity, along with external radiation and natural convective cooling, while the latter depends significantly more on the tokamak's sizeable total internal heat capacity. This difference originates from the fusion-fission reactor's conflicting goal of having to minimize heat transfer to the magnets during normal operation. These results are discussed in the context of overall fusion-fission reactor design and safety

  12. Bed mixing dryer for high moisture content fuels

    Energy Technology Data Exchange (ETDEWEB)

    Hulkkonen, S.; Heinonen, O. [Imatran Voima Oy, Vantaa (Finland)

    1997-12-31

    Bed mixing dryer is a new type of fuel drying technology for fluidized bed combustion. The idea is to extract hot bed material from the fluidized bed and use it as a heat source for drying the fuel. Drying occurs at steam atmosphere which makes it possible to recover the latent heat of evaporation to process. This improves the thermal efficiency of the power plant process considerably, especially in combined heat and power applications. Imatran Voima Oy (IVO) has developed the Bed Mixing Dryer technology since early 1990s. The first pilot plant was built in 1994 to IVO`s Kuusamo peat and wood fired power plant. The capacity of the plant is 6 MW{sub e} and 20 MW of district heat. In Kuusamo the dryer is connected to a bubbling fluidized bed. Since it`s commissioning the dryer has been used successfully for about 3000 hours during the heating season in wintertime. The second application of the technology will be a demonstration project in Oerebro (S). IVO Power Engineering Ltd will supply in 1997 a dryer to Oerebro Energi`s peat, wood and coal fired CHP plant equipped with circulating fluidized bed boiler. The fuel to be dried is sawdust with fuel input of about 60 MW. In Kuusamo the dryer produces 3 MW of additional district heat and in Oerebro 6 MW. The fuels in Kuusamo are peat, saw dust and bark. In addition to the municipal heat production this type of drying technology has its benefits in pulp and paper industry processes. Disposal of paper mill sludges is becoming more difficult and costly which has resulted in need of alternative treatment. Drying of the sludge before combustion in a boiler for power production is an attractive option. At the moment IVO is carrying out several studies to apply the Bed Mixing Dryer in pulp and paper industry processes. Economy of drying the sludge looks promising

  13. 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.)

  14. 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

  15. CO2 capture at ambient temperature in a fixed bed with CaO-based sorbents

    International Nuclear Information System (INIS)

    Highlights: • CaO-based pellets can be used for CO2 capture at ambient temperature. • Pre-hydration of pellets improves CO2 capture capacity significantly. • CO2 capture capacity of 0.5 g/g is obtained in a CaO-based fixed bed. • The capture capacity is sensitive to moisture and CO2 inlet concentration. - Abstract: This work investigates post-combustion CO2 capture at ambient temperature in a fixed bed by means of CaO-based sorbents. Two sorbents were used: limestone and pellets prepared from powdered limestone using calcium aluminate cement as a binder. The results showed that pre-hydration had a significant effect on CO2 capture performance of the two sorbents. For instance, after 8 h pre-hydration, the breakthrough time increased from 21 min to 660 min for lime, and from 19 min to 750 min for pellets. The performance of pellets was more sensitive to hydration conditions than for the lime. At breakthrough, full carbonation conversion over half of the reactor was achieved in a pre-hydrated bed of pellets exposed to a feed with 0.5% CO2, resulting in an average specific capture of 0.51 g CO2/g bed material. This was considered a sufficient capture performance, with a distinct mass transfer zone (MTZ) located in the upper half of the reactor. However, increasing CO2 inlet concentration to 2% shortened the breakthrough time and shifted the MTZ toward the entrance zone of the reactor. It was concluded that capturing CO2 from low-CO2 flue gases at ambient temperature using a fixed bed of pre-hydrated CaO-based pellets is a promising approach that has the potential to achieve reasonable capture performance at relatively low cost. The proposed process can be used for CO2 capture from CO2-depleted flue gases (residual CO2) from processes such as amine scrubbing and calcium looping. And it would allow for the possibility that capture could be increased to any given level required by new legislation for plant with carbon capture

  16. Multi-Bed Multi-Stage Adsorption Refrigeration Cycle-Reducing Driving Heat Source Temperature

    Science.gov (United States)

    Alam, K. C. Amanul; Akahira, Akira; Hamamoto, Yoshinori; Akisawa, Atsushi; Kashiwagi, Takao; Saha, Bidyut Baran; Koyama, Shigeru; Ng, Kim Choon; Chua, Hui Tong

    The study aims at designing a multi-bed multi-stage adsorption chiller that can be driven by waste heat at near ambient temperature. The chiller is designed such a way that it can be switched into different modes depending on the driving heat source temperature. Stage regeneration techniques have been applied to operate the chiller by relatively low temperature heat source. Driving heat source temperature is validated by simulated data and the performances obtained from different modes are compared. In terms of COP (Coefficient of performance),the chiller shows best performance in conventional single-stage mode for driving heat source temperature greater than 60°C, two stage mode for driving source temperature between 42 and 60°C,in three-stage mode for driving source temperature less than 42°C. In terms of cooling capacity, it shows the best performance in single-stage mode for heat source temperature greater than 70°C. The mass recovery process in single-stage mode is also examined. It is seen that the mass recovery process improve cooling capacity significantly, specially for the low regenerating temperature region.

  17. High temperature interface superconductivity

    Science.gov (United States)

    Gozar, A.; Bozovic, I.

    2016-02-01

    High-Tc superconductivity at interfaces has a history of more than a couple of decades. In this review we focus our attention on copper-oxide based heterostructures and multi-layers. We first discuss the technique, atomic layer-by-layer molecular beam epitaxy (ALL-MBE) engineering, that enabled High-Tc Interface Superconductivity (HT-IS), and the challenges associated with the realization of high quality interfaces. Then we turn our attention to the experiments which shed light on the structure and properties of interfacial layers, allowing comparison to those of single-phase films and bulk crystals. Both 'passive' hetero-structures as well as surface-induced effects by external gating are discussed. We conclude by comparing HT-IS in cuprates and in other classes of materials, especially Fe-based superconductors, and by examining the grand challenges currently laying ahead for the field.

  18. High Temperature Electrostrictive Ceramics Project

    Data.gov (United States)

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

  19. [Influence of Temperature on the Anaerobic Packed Bed Reactor Performance and Methanogenic Community].

    Science.gov (United States)

    Xie, Hai-ying; Wang, Xin; Li, Mu-yuan; Yan, Xu-you; Igarashi, Yasuo; Luo, Feng

    2015-11-01

    This study aimed to analyze the effect of temperature on performance and microbial community structure of an anaerobic packed bed reactor (APBR). The temperature was increased step-wise from room temperature (22 degrees C ± 1 degrees C) to psychrophilic (15 degrees C ± 1 degrees C), mesophilic (37 degrees C ± 1 degrees C) and thermophilic (55 degrees C ± 1 degrees C). The results showed that, in the temperature changing process, the higher the temperature of APBR was, the higher COD removal rate and daily gas production were. After temperature changed to psychrophilic, mesophilic and thermophilic, COD removal rate and daily gas production were 25%, 45%, 60% and 2.3 L x d(-1), 4.0 L x d(-1), 8.5 L x d(-1) respectively. However, there was no significant change in biogas composition (-60%). A sudden temperature change caused a simultaneous increase in the concentration of volatile fatty acids (VFA), which had been fluctuating. Using 16S rRNA gene clone library screening, Euryarchaeota was commonly found, including important methanogens: MBT (Methanobacteriales), Mst (Methanosaetaceae) , Msc (Methanosarcinaceae) and MMB (Methanomicrobiales), as well as thermophilic bacteria and few spring Archaea. However, the diversity of methanogenic groups was reduced, especially at mesophilic. The results of quantitative PCR showed that the 16S rRNA gene concentrations of Mst, MMB and Msc were reduced by temperature changes. Although the relative proportion of every kind of methanogen was significantly affected, Mst was the dominant methanogen. PMID:26911011

  20. Water and sediment temperatures at mussel beds in the upper Mississippi River basin

    Science.gov (United States)

    Newton, Teresa J.; Sauer, Jennifer; Karns, Byron

    2013-01-01

    Native freshwater mussels are in global decline and urgently need protection and conservation. Declines in the abundance and diversity of North American mussels have been attributed to human activities that cause pollution, waterquality degradation, and habitat destruction. Recent studies suggest that effects of climate change may also endanger native mussel assemblages, as many mussel species are living close to their upper thermal tolerances. Adult and juvenile mussels spend a large fraction of their lives burrowed into sediments of rivers and lakes. Our objective was to measure surface water and sediment temperatures at known mussel beds in the Upper Mississippi (UMR) and St. Croix (SCR) rivers to estimate the potential for sediments to serve as thermal refugia. Across four mussel beds in the UMR and SCR, surface waters were generally warmer than sediments in summer, and were cooler than sediments in winter. This suggests that sediments may act as a thermal buffer for mussels in these large rivers. Although the magnitude of this effect was usually <3.0°C, sediments were up to 7.5°C cooler at one site in May, suggesting site-specific variation in the ability of sediments to act as thermal buffers. Sediment temperatures in the UMR exceeded those shown to cause mortality in laboratory studies. These data suggest that elevated water temperatures resulting from global warming, thermal discharges, water extraction, and/or droughts have the potential to adversely affect native mussel assemblages.

  1. Modeling of river bed deformation composed of frozen sediments with increasing environmental temperature

    Directory of Open Access Journals (Sweden)

    E. I. Debolskaya

    2013-01-01

    Full Text Available This paper is devoted to investigation of the influence of river flow and of the temperature rise on the deformation of the coastal slopes composed of permafrost with the inclusion of ice layer. The method of investigation is the laboratory and mathematical modeling. The laboratory experiments have shown that an increase in water and air temperature changes in a laboratory analogue of permafrost causes deformation of the channel even without wave action, i.e. at steady-state flow and non-erosive water flow velocity. The previously developed model of the bed deformation was improved to account for long-term changes of soil structure with increasing temperature. The three-dimensional mathematical model of coastal slopes thermoerosion of the rivers flowing in permafrost regions, and its verification was based on the results of laboratory experiments conducted in the hydraulic tray. Analysis of the results of mathematical and laboratory modeling showed that bed deformation of the rivers flowing in the permafrost zone, significantly different from the deformation of channels composed of soils not susceptible to the influence of the phase transition «water-ice», and can occur even under the non-erosive velocity of the water flow.

  2. Analysis of the high-temperature particulate collection problem

    Energy Technology Data Exchange (ETDEWEB)

    Razgaitis, R.

    1977-10-01

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

  3. Modeling the microbial growth and temperature profile in a fixed-bed bioreactor.

    Science.gov (United States)

    da Silveira, Christian L; Mazutti, Marcio A; Salau, Nina P G

    2014-10-01

    Aiming to scale up and apply control and optimization strategies, currently is required the development of accurate plant models to forecast the process nonlinear dynamics. In this work, a mathematical model to predict the growth of the Kluyveromyces marxianus and temperature profile in a fixed-bed bioreactor for solid-state fermentation using sugarcane bagasse as substrate was built up. A parameter estimation technique was performed to fit the mathematical model to the experimental data. The estimated parameters and the model fitness were evaluated with statistical analyses. The results have shown the estimated parameters significance, with 95 % confidence intervals, and the good quality of process model to reproduce the experimental data.

  4. Hydrodynamic description of a vibrofluidized granular bed driven at high frequency

    Science.gov (United States)

    Sheikh, Nadeem A.; Manzoor, Shehryar; Mahabat Khan, Muhammad; Ali, Muzaffar

    2016-08-01

    Results are reported for a dry granular bed vertically excited at high and low frequencies with constant peak base velocity. Previous experimental data sets using Nuclear Magnetic Resonance are used for comparison at low (~38 Hz) and high (~11 kHz) vibration frequencies. Packing fractions and granular temperatures are compared against hydrodynamic and molecular dynamics simulation models. At low frequency hydrodynamic and MD simulations results show the presence of a heat wave. Whilst at high frequencies soft sphere potential based MD simulations highlight the role of finite duration collisions between particles and the vibrating wall. In this region the timescales of vibration and collision duration are not well separated, as observed in experimental results.

  5. An investigation of moving bed biofilm reactor nitrification during long-term exposure to cold temperatures.

    Science.gov (United States)

    Hoang, Valerie; Delatolla, Robert; Laflamme, Edith; Gadbois, Alain

    2014-01-01

    Biological treatment is the most common and economical means of ammonia removal in wastewater; however, nitrification rates can become completely impeded at cold temperatures. Attached growth processes and, specifically, moving bed biofilm reactors (MBBRs) have shown promise with respect to low-temperature nitrification. In this study, two laboratory MBBRs were used to investigate MBBR nitrification rates at 20, 5, and 1 degree C. Furthermore, the solids detached by the MBBR reactors were investigated and Arrhenius temperature correction models used to predict nitrification rates after long-term low-temperature exposure was evaluated. The nitrification rate at 5 degrees C was 66 +/- 3.9% and 64 +/- 3.7% compared to the rate measured at 20 degrees C for reactors 1 and 2, respectively. The nitrification rates at 1 degree C over a 4-month exposure period compared to the rate at 20 degrees C were 18.7 +/- 5.5% and 15.7 +/- 4.7% for the two reactors. The quantity of solids detached from the MBBR biocarriers was low and the mass of biofilm per carrier did not vary significantly at 20 degrees C compared to that after long-term exposure at 1 degree C. Lastly, a temperature correction model based on exposure time to cold temperatures showed a strong correlation to the calculated ammonia removal rates relative to 20 degrees C following a gradual acclimatization period to cold temperatures.

  6. Fluidisation and dispersion behaviour of small high density pellicular expanded bed adsorbents

    DEFF Research Database (Denmark)

    Theodossiou, Irini; Elsner, H.D.; Thomas, Owen R. T.;

    2002-01-01

    The fluidisation and dispersion properties of various agarose-based expanded bed matrices-small high density stainless steel cored prototypes and standard commercial types-were studied in I-cm diameter expanded bed contactors in which fluid entering the column base is locally stirred. In all cases...

  7. The influence of temperature on limestone sulfation and attrition under fluidized bed combustion conditions

    Energy Technology Data Exchange (ETDEWEB)

    Montagnaro, Fabio [Dipartimento di Chimica - Universita degli Studi di Napoli Federico II, Complesso Universitario del Monte di Sant' Angelo, 80126 Napoli (Italy); Salatino, Piero [Istituto di Ricerche sulla Combustione - CNR, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy); Dipartimento di Ingegneria Chimica - Universita degli Studi di Napoli Federico II, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy); Scala, Fabrizio [Istituto di Ricerche sulla Combustione - CNR, Piazzale Vincenzo Tecchio 80, 80125 Napoli (Italy)

    2010-04-15

    The influence of temperature on attrition of two limestones during desulfurization in a fluidized bed reactor was investigated. Differences in the microstructure of the two limestones were reflected by a different thickness of the sulfate shell formed upon sulfation and by a different value of the ultimate calcium conversion degree. Particle attrition and fragmentation were fairly small under moderately bubbling fluidization conditions for both limestones. An increase of temperature from 850 C to 900 C led to an increase of the attrition rate, most likely because of a particle weakening effect caused by a faster CO{sub 2} evolution during calcination. This weakening effect, however, was not sufficiently strong to enhance particle fragmentation in the bed. The progress of sulfation, associated to the build-up of a hard sulfate shell around the particles, led in any case to a decrease of the extent of attrition. Sulfation at 900 C was less effective than at 850 C, and this was shown to be related to the porosimetric features of the different samples. (author)

  8. Surface modification of the nanoparticles by an atmospheric room-temperature plasma fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Chen Guangliang [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)], E-mail: glchen@zstu.edu.cn; Chen Shihua [Department of Civil and Environmental Engineering, Syracuse University, Syracuse, NY 13244 (United States); Feng Wenran [Department of Materials Science and Engineering, Beijing Institute of Petrochemical Technology, Beijing 102617 (China); Chen Wenxing [Key Laboratory of Advanced Textile Materials and Manufacturing Technology, Ministry of Education, Zhejiang Sci-Tech University, Hangzhou 310018 (China); Yang Size [Beijing National Laboratory for Condensed Matter Physics, Institute of Physics, Chinese Academy of Sciences, Beijing 100080 (China)

    2008-04-30

    Using hexamethyldisiloxane (HMDSO) monomer, the magnetic nanoparticles (NPs) of nickel oxide (NiO) were modified by using an atmospheric room-temperature plasma fluidized bed (ARPFB). The plasma gas temperature of the ARPFB was not higher than 325 K, which was favorable for organic polymerization. The plasma optical emission spectrum (OES) of the gas mixture consisting of argon (Ar) and HMDSO was recorded by a UV-visible monochromator. The as-treated NPs were characterized by means of scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The results show that the assembling NPs were isolated greatly after modified by the organosilicon polymer. Moreover, this treatment process changed the wettability of the NPs from super-hydrophilicity to super-hydrophobicity, and the contact angle (CA) of water on the modified NPs surface exceeded 150 deg. Therefore, the ARPFB is a prospective technology for the NPs surface modification according to the different requirements.

  9. Influence of temperature and particle size on the fixed bed pyrolysis of orange peel residues

    Energy Technology Data Exchange (ETDEWEB)

    Aguiar, L. [Departamento de Mecanica, Universidad de Pinar del Rio, Cuba. Calle Marti 270, final, Pinar del Rio (Cuba); Marquez-Montesinos, F. [Departamento de Quimica, Universidad de Pinar del Rio, Cuba. Calle Marti 270, final, Pinar del Rio (Cuba); Gonzalo, A.; Sanchez, J.L.; Arauzo, J. [Thermochemical Processes Group (GPT), Aragon Institute for Engineering Research (I3A), University of Zaragoza, Maria de Luna 3, 50018 Zaragoza (Spain)

    2008-09-15

    Orange peel is a residue from the production of juice. Its energetic valorisation could be interesting in areas where a different use, such as animal feed, is not possible. In order to investigate the viability of energy recovery, the pyrolysis of orange peel residues was studied in a fixed bed reactor, as an initial assessment of this process. The influence of pyrolysis temperature (300-600 C) and particle size (d{sub p}<300{mu}m and d{sub p}>800{mu}m) on product distribution, gas composition and char heating value has been investigated using a factorial design of experiments. Gas, char and water are the main products obtained; tar is only about 6 wt.% of the initial residue. Temperature was found to be the parameter which exerts a more important influence on the results than particle size. (author)

  10. High Temperature Materials Laboratory (HTML)

    Data.gov (United States)

    Federal Laboratory Consortium — The six user centers in the High Temperature Materials Laboratory (HTML), a DOE User Facility, are dedicated to solving materials problems that limit the efficiency...

  11. High Temperature Bell Motor Project

    Data.gov (United States)

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

  12. Agglomeration behaviour of high ash Indian coals in fluidized bed gasification pilot plant

    International Nuclear Information System (INIS)

    Although gasification of high ash Indian coals is gaining importance, the resultant uncertainties associated with agglomerate formation are still unresolved. To address this, a suitable pilot scale Fluidized Bed Gasifier was utilized in this study. Stabilized operating conditions in terms of coal feed rate, air feed rate, bed temperature, etc., already identified for maximum possible carbon conversion, were maintained in all experiments and the steam flow rate was only varied. Though the ash fusion temperature of the coals were above 1200 °C, agglomerate was formed during gasification at 950 °C with ‘steam to coal ratio’ less than 0.15 (kg/kg). On increasing this ratio above 0.2 local heat-concentration and agglomeration could be avoided with certainty. Chemical composition alone was not sufficient to explain the relative strength of ash-agglomerates. Compositional variation and state of iron within the matrix were assessed through SEM-EDX and electron paramagnetic resonance (EPR) study, respectively. The probing also required the ash-loading and iron-loading factors to be freshly defined in the context of gasification. Localized heat, large compositional variation, presence of iron in Fe2+ state, ash-loading/iron-loading factors influenced intensity of agglomerate formation. Finally, low temperature agglomerate formation was explained by SiO2–Al2O3–FeO phase diagram. - Highlights: • Pilot plant studies on agglomerate formation during high ash coal gasification. • AFT, chemical analysis of coal ash could not give proper indication. • Ash-/iron-loading factors, compositional variation, Fe2+ leads to agglomeration. • Steam to coal ratio was controlled judiciously to avoid agglomeration. • Cause for agglomeration investigated in depth and remedial adjustment was focused

  13. High temperature high vacuum creep testing facilities

    International Nuclear Information System (INIS)

    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

  14. High-temperature Titanium Alloys

    OpenAIRE

    A.K. Gogia

    2005-01-01

    The development of high-temperature titanium alloys has contributed significantly to the spectacular progress in thrust-to-weight ratio of the aero gas turbines. This paper presents anoverview on the development of high-temperature titanium alloys used in aero engines and potential futuristic materials based on titanium aluminides and composites. The role of alloychemistry, processing, and microstructure, in determining the mechanical properties of titanium alloys is discussed. While phase eq...

  15. High temperature ultrasonic transducers: review

    OpenAIRE

    Kažys, R.; Voleišis, A.; Voleišienė, B.

    2008-01-01

    The problems of development of high-temperature ultrasonic transducers for modern science and technology applications are analysed. More than 10 piezoelectric materials suitable for operation at high temperatures are overviewed. It is shown that bismuth titanate based piezoelectric elements are most promisable. Bonding methods of piezoelectric elements to a protector and backing are discussed. Thermosonic gold-to-gold bonding is most modern and possesses unique features. Our achievements in t...

  16. Effect of temperature and salinity on the wastewater treatment performance of aerobic submerged fixed bed biofilm reactors.

    Science.gov (United States)

    Chapanova, G; Jank, M; Schlegel, S; Koeser, H

    2007-01-01

    The influence of temperature (5-35 C) and salinity (up to 20 g/l NaCl) on the wastewater purification process in completely mixed and aerated submerged fixed bed biofilm reactors (SFBBRs) was studied. C- and N-conversion in SFBBRs designed according to the DWA (German Association for Water, Wastewater and Waste) rules for carbon removal was investigated for several months on synthetic wastewater. The DOC degradation rate was even at, according to the DWA, high DOC/BOD loading rates not much affected by temperatures between 5-35 degrees C and salt contents up to 20 g/L NaCl. At these high DOC loadings an appreciable ammonium conversion could also be observed. The ammonium conversion proved to be sensitive to temperature and salinity. At 5 degrees C the ammonium removal rate decreased by a factor of five compared to 25-35 degrees C. Under many operation conditions investigated more than 50% of the converted ammonium was transformed into gaseous nitrogen. The addition of 20 g/L NaCl caused a strong inhibition of the ammonium removal rate over the whole temperature range investigated.

  17. High temperature corrosion of metals

    International Nuclear Information System (INIS)

    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)

  18. Modeling the temperature in coal char particle during fluidized bed combustion

    Energy Technology Data Exchange (ETDEWEB)

    Vasilije Manovic; Mirko Komatina; Simeon Oka [University of Belgrade, Belgrade (Serbia)

    2008-05-15

    The temperatures of a coal char particle in hot bubbling fluidized bed (FB) were analyzed by a model of combustion. The unsteady model includes phenomena of heat and mass transfer through a porous char particle, as well as heterogeneous reaction at the interior char surface and homogeneous reaction in the pores. The parametric analysis of the model has shown that above 550{sup o}C combustion occurs under the regime limited by diffusion. The experimental results of temperature measurements by thermocouple in the particle center during FB combustion at temperatures in the range 590-710{sup o}C were compared with the model predictions. Two coals of different rank were used: lignite and brown coal, with particle size in the range 5-10 mm. The comparisons have shown that the model can adequately predict the histories of temperatures in char particles during combustion in FB. In the first order, the model predicts the influence of the particle size, coal rank (via porosity), and oxygen concentration in its surroundings. 53 refs., 6 figs., 2 tabs.

  19. 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.

  20. Simulation of a high efficiency multi-bed adsorption heat pump

    International Nuclear Information System (INIS)

    Attaining high energy efficiency with adsorption heat pumps is challenging due to thermodynamic losses that occur when the sorbent beds are thermally cycled without effective heat recuperation. The multi-bed concept described here enables high efficiency by effectively transferring heat from beds being cooled to beds being heated. A simplified lumped-parameter model and detailed finite element analysis are used to simulate a sorption compressor, which is used to project the overall heat pump coefficient of performance. Results are presented for ammonia refrigerant and a nano-structured monolithic carbon sorbent specifically modified for the application. The effects of bed geometry and number of beds on system performance are explored, and the majority of the performance benefit is obtained with four beds. Results indicate that a COP of 1.24 based on heat input is feasible at AHRI standard test conditions for residential HVAC equipment. When compared on a basis of primary energy input, performance equivalent to SEER 13 or 14 are theoretically attainable with this system. - Highlights: ► A multi-bed concept for adsorption heat pumps is capable of high efficiency. ► Modeling is used to simulate sorption compressor and overall heat pump performance. ► Results are presented for ammonia refrigerant and a nano-structured monolithic carbon sorbent. ► The majority of the efficiency benefit is obtained with four beds. ► Predicted COP as high as 1.24 for cooling is comparable to SEER 13 or 14 for electric heat pumps.

  1. Solute strengthening at high temperatures

    Science.gov (United States)

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

    2016-08-01

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

  2. Solute strengthening at high temperatures

    Science.gov (United States)

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

    2016-08-01

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

  3. HIgh Temperature Photocatalysis over Semiconductors

    Science.gov (United States)

    Westrich, Thomas A.

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

  4. 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...... temperature allows for utilization of the excess heat for fuel processing. Moreover, it provides an excellent CO tolerance of several percent, and the system needs no purification of hydrogen from a reformer. Continuous service for over 6 months at 150°C has been demonstrated....

  5. 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...... winding comprising four coils wound with two types of HTS tapes are shown and discussed. The field winding produces up to 0.62T in the 10mm air gap which constitutes 78% of the armature design value. Recommendations for the field winding operation are proposed and verified, which resulted in an increase...

  6. High temperature thermoelectric energy conversion

    International Nuclear Information System (INIS)

    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

  7. Diamond for High Power / High Temperature Electronics

    OpenAIRE

    Kohn, E.; Kubovic, M.; Hernandez-Guillen, F.; Denisenko, A.

    2004-01-01

    Diamond is a wide bandgap semiconductor with extremely attractive properties but also many technological difficulties. Doping is restricted to deep impurities and substrate size is very limited. Nevertheless in proof of concept experiments, the potential for high power, high temperature and high frequency applications can already well be estimated. In addition, first passive MEMS elements for advanced circuit applications have also been demonstrated, however still on n...

  8. High-Temperature Optical Sensor

    Science.gov (United States)

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

    2010-01-01

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

  9. Influences of Temperature and Coal Particle Size on the Flash Pyrolysis of Coal in a Fast-entrained Bed

    Institute of Scientific and Technical Information of China (English)

    2006-01-01

    The experiments on the flash pyrolysis of a lignite were carried out in a fast-entrained bed reactor as a basic study on a so-called 'coal topping process'. The investigation focused on the effects of pyrolysis temperature and coal particle size on the product distribution and composition. The experimental results show that an increase in the pyrolysis temperature results in a higher yield of gaseous products while a larger particle size leads to a decrease of the liquid yield. An optimum temperature for the liquid yield was found to be 650 ℃. A certain amount of phenol groups was found in the liquid products, which may be used to produce high-valued fine chemicals. The FTIR analyses of the coal and chars show that aliphatic structures in the chars are gradually replaced by aromatic structures with the increasing of pyrolysis temperature and coal particle size. The results of this study provide fundamental data and optimal conditions to maximize light oils yields for the coal topping process.

  10. High gradient magnetic separation versus expanded bed adsorption: a first principle comparison

    DEFF Research Database (Denmark)

    Hubbuch, Jürgen; Matthiesen, D.B.; Hobley, Timothy John;

    2001-01-01

    system exhibited substantially enhanced productivity over expanded bed adsorption when operated at processing velocities greater than 48 m h(-1). Use of the bacitracin- linked magnetic supports for a single cycle of batch adsorption and subsequent capture by high gradient magnetic separation...... at a processing rate of 12 m h(-1) resulted in a 2.2-fold higher productivity relative to expanded bed adsorption, while an increase in adsorbent collection rate to 72 m h(-1) raised the productivity to 10.7 times that of expanded bed adsorption. When the number of batch adsorption cycles was then increased...

  11. Nonlinear plasmonics at high temperatures

    CERN Document Server

    Sivan, Yonatan

    2016-01-01

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

  12. High-temperature Titanium Alloys

    Directory of Open Access Journals (Sweden)

    A.K. Gogia

    2005-04-01

    Full Text Available The development of high-temperature titanium alloys has contributed significantly to the spectacular progress in thrust-to-weight ratio of the aero gas turbines. This paper presents anoverview on the development of high-temperature titanium alloys used in aero engines and potential futuristic materials based on titanium aluminides and composites. The role of alloychemistry, processing, and microstructure, in determining the mechanical properties of titanium alloys is discussed. While phase equilibria and microstructural stability consideration haverestricted the use of conventional titanium alloys up to about 600 "C, alloys based on TiPl (or,, E,AINb (0, TiAl (y, and titaniumltitanium aluminides-based composites offer a possibility ofquantum jump in the temperature capability of titanium alloys.

  13. High-Temperature Vibration Damper

    Science.gov (United States)

    Clarke, Alan; Litwin, Joel; Krauss, Harold

    1987-01-01

    Device for damping vibrations functions at temperatures up to 400 degrees F. Dampens vibrational torque loads as high as 1,000 lb-in. but compact enough to be part of helicopter rotor hub. Rotary damper absorbs energy from vibrating rod, dissipating it in turbulent motion of viscous hydraulic fluid forced by moving vanes through small orifices.

  14. High-Temperature Electrostatic Levitator

    Science.gov (United States)

    Rhim, Won-Kyu; Chung, Sang K.

    1994-01-01

    High-temperature electrostatic levitator provides independent control of levitation and heating of sample in vacuum. Does not cause electromagnetic stirring in molten sample (such stirring causes early nucleation in undercooling). Maintenance of levitating force entails control of electrostatic field and electrical charge on sample.

  15. Chemistry of high temperature superconductors

    CERN Document Server

    1991-01-01

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

  16. Establishing Bedding Requirements during Transport and Monitoring Skin Temperature during Cold and Mild Seasons after Transport for Finishing Pigs

    Directory of Open Access Journals (Sweden)

    John McGlone

    2014-05-01

    Full Text Available The broad aim of this study was to determine whether bedding level in the transport trailer influenced pig performance and welfare. Specifically, the objective was to define the bedding requirements of pigs during transportation in commercial settings during cold and mild weather. Animals (n = 112,078 pigs on 572 trailers used were raised in commercial finishing sites and transported in trailers to commercial processing plants. Dead on arrival (DOA, non-ambulatory (NA, and total dead and down (D&D data were collected and skin surface temperatures of the pigs were measured by infrared thermography. Data were collected during winter (Experiment 1 and fall/spring (Experiment 2. Total D&D percent showed no interaction between bedding level and outside air temperature in any experiments. Average skin surface temperature during unloading increased with outside air temperature linearly in both experiments (P < 0.01. In conclusion, over-use of bedding may be economically inefficient. Pig skin surface temperature could be a useful measure of pig welfare during or after transport.

  17. High Temperature, High Power Piezoelectric Composite Transducers

    Directory of Open Access Journals (Sweden)

    Hyeong Jae Lee

    2014-08-01

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

  18. 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

  19. High temperature, high power piezoelectric composite transducers.

    Science.gov (United States)

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

    2014-08-08

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

  20. 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

  1. An Experimental Study on Axial Temperature Distribution of Combustion of Dewatered Poultry Sludge in Fluidized bed combustor

    Directory of Open Access Journals (Sweden)

    Abbas A.H.

    2016-01-01

    Full Text Available A laboratory scale bubbling fluidized bed combustor was designed and fabricated to study the combustion of dewatered poultry sludge at different operational parameters. This paper present a study on the influence of equivalent ratio, secondary to primary air ratio and the fuel feed rate on the temperature distribution along the combustor. The equivalent ratio has been changed between 0.8 to 1.4% under poultry sludge feed rate of 10 kg/h and from 0.8 to 1 under poultry sludge feed rate of 15 kg/h. The secondary to primary air ratio was varied from 0.1 to 0.5 at 0.65 m injection height and 1.25 equivalent ratio. The results showed that these factors had a significant influence on the combustion characteristics of poultry sludge. The temperature distribution along the combustor was found to be strongly dependent on the fuel feed rate and the equivalent ratio and it increased when these two factors increased. However, the secondary air ratio increased the temperature in the lower region of the combustor while no significant effect was observed at the upper region of the combustor. The results suggested that the poultry sludge can be used as a fuel with high thermal combustor efficiency.

  2. Preliminary Neutronic Design of High Burnup OTTO Cycle Pebble Bed Reactor

    Directory of Open Access Journals (Sweden)

    T. Setiadipura

    2015-04-01

    Full Text Available The pebble bed type High Temperature Gas-cooled Reactor (HTGR is among the interesting nuclear reactor designs in terms of safety and flexibility for co-generation applications. In addition, the strong inherent safety characteristics of the pebble bed reactor (PBR which is based on natural mechanisms improve the simplicity of the PBR design, in particular for the Once-Through-Then-Out (OTTO cycle PBR design. One of the important challenges of the OTTO cycle PBR design, and nuclear reactor design in general, is improving the nuclear fuel utilization which is shown by attaining a higher burnup value. This study performed a preliminary neutronic design study of a 200 MWt OTTO cycle PBR with high burnup while fulfilling the safety criteria of the PBR design.The safety criteria of the design was represented by the per-fuel-pebble maximum power generation of 4.5 kW/pebble. The maximum burnup value was also limited by the tested maximum burnup value which maintained the integrity of the pebble fuel. Parametric surveys were performed to obtain the optimized parameters used in this study, which are the fuel enrichment, per-pebble heavy metal (HM loading, and the average axial speed of the fuel. An optimum design with burnup value of 131.1 MWd/Kg-HM was achieved in this study which is much higher compare to the burnup of the reference design HTR-MODUL and a previously proposed OTTO-cycle PBR design. This optimum design uses 17% U-235 enrichment with 4 g HM-loading per fuel pebble

  3. Preliminary neutronic design of high burnup OTTO cycle pebble bed reactor

    International Nuclear Information System (INIS)

    The pebble bed type High Temperature Gas-cooled Reactor (HTGR) is among the interesting nuclear reactor designs in terms of safety and flexibility for co-generation applications. In addition, the strong inherent safety characteristics of the pebble bed reactor (PBR) which is based on natural mechanisms improve the simplicity of the PBR design, in particular for the Once-Through-Then-Out (OTTO) cycle PBR design. One of the important challenges of the OTTO cycle PBR design, and nuclear reactor design in general, is improving the nuclear fuel utilization which is shown by attaining a higher burnup value. This study performed a preliminary neutronic design study of a 200 MWt OTTO cycle PBR with high burnup while fulfilling the safety criteria of the PBR design.The safety criteria of the design was represented by the per-fuel-pebble maximum power generation of 4.5 kW/pebble. The maximum burnup value was also limited by the tested maximum burnup value which maintained the integrity of the pebble fuel. Parametric surveys were performed to obtain the optimized parameters used in this study, which are the fuel enrichment, per-pebble heavy metal (HM) loading, and the average axial speed of the fuel. An optimum design with burnup value of 131.1 MWd/Kg-HM was achieved in this study which is much higher compare to the burnup of the reference design HTR-MODUL and a previously proposed OTTO-cycle PBR design. This optimum design uses 17% U-235 enrichment with 4 g HM-loading per fuel pebble. (author)

  4. A High-Voltage Test Bed for the Evaluation of High-Voltage Dividers for Pulsed Applications

    CERN Document Server

    Bastos, M C; Hammarquist, M

    2011-01-01

    The design, evaluation, and commissioning of a high-voltage reference test bed for pulsed applications to be used in the precision testing of high-voltage dividers is described. The test bed is composed of a pulsed power supply, a reference divider based on compressed-gas capacitor technology, and an acquisition system that makes use of the fast measurement capabilities of the HP3458 digital voltmeter. The results of the evaluation of the reference system are presented.

  5. NSTX High Temperature Sensor Systems

    International Nuclear Information System (INIS)

    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

  6. The Design of Impact Test-Bed for High-Flow Water Medium Relief Valve

    OpenAIRE

    Junliang Chang; Lei Liu; Jiyun Zhao; Haigang Ding; Gaoliang Shi

    2014-01-01

    Water medium hydraulic systems are widely used in coal mining machinery. As the power of hydraulic system becomes higher, the flow and pressure of water medium relief valve are also higher, and the flow may reach 2000 L/min. However, there is no relevant test-bed which could provide instantaneous high-pressure and high-flow to support the experiment for high-flow relief valve; consequently, this impact test-bed for high-flow water medium relief valve is designed to satisfy fast loading demand...

  7. High Temperature Heat Exchanger Project

    Energy Technology Data Exchange (ETDEWEB)

    Anthony E. Hechanova, Ph.D.

    2008-09-30

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

  8. Motor for High Temperature Applications

    Science.gov (United States)

    Roopnarine (Inventor)

    2013-01-01

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

  9. HIGH TEMPERATURE MICROSCOPE AND FURNACE

    Science.gov (United States)

    Olson, D.M.

    1961-01-31

    A high-temperature microscope is offered. It has a reflecting optic situated above a molten specimen in a furnace and reflecting the image of the same downward through an inert optic member in the floor of the furnace, a plurality of spaced reflecting plane mirrors defining a reflecting path around the furnace, a standard microscope supported in the path of and forming the end terminus of the light path.

  10. Very High Temperature Sound Absorption Coating Project

    Data.gov (United States)

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

  11. Fluidized-bed calcination of simulated commercial high-level radioactive wastes

    International Nuclear Information System (INIS)

    Work is in progress at the Idaho Chemical Processing Plant to verify process flowsheets for converting simulated commercial high-level liquid wastes to granular solids using the fluidized-bed calcination process. Primary emphasis in the series of runs reported was to define flowsheets for calcining simulated Allied-General Nuclear Services (AGNS) waste and to evaluate product properties significant to calcination, solids storage, or post treatment. Pilot-plant studies using simulated high-level acid wastes representative of those to be produced by Nuclear Fuel Services, Inc. (NFS) are also included. Combined AGNS high-level and intermediate-level waste (0.26 M Na in blend) was successfully calcined when powdered iron was added (to result in a Na/Fe mole ratio of 1.0) to the feed to prevent particle agglomeration due to sodium nitrate. Long-term runs (approximately 100 hours) showed that calcination of the combined waste is practical. Concentrated AGNS waste containing sodium at concentrations less than 0.2 M were calcined successfully; concentrated waste containing 1.13 M Na calcined successfully when powdered iron was added to the feed to suppress sodium nitrate formation. Calcination of dilute AGNS waste by conventional fluid-bed techniques was unsuccessful due to the inability to control bed particle size--both particle size and bed level decreased. Fluid-bed solidification of AGNS dilute waste at conditions in which most of the calcined solids left the calciner vessel with the off-gas was successful. In such a concept, the steady-state composition of the bed material would be approximately 22 wt percent calcined solids deposited on inert particles. Calcination of simulated NFS acid waste indicated that solidification by the fluid-bed process is feasible

  12. Graphite high temperature creep rigs

    International Nuclear Information System (INIS)

    A description is given of two high temperature tensile creep rigs, for irradiating pyrocarbon and graphite specimens. PIRITHOOS is a creep rig operating at 1100 deg C and utilizing three in line pyrocarbon specimens. These have different cross sections giving three stress values. Unstressed specimens are placed close to the tensile ones. Dimensional measurements: length, thickness, width are made in hot cells, after each reactor shut down. FLACH is a graphite creep rig allowing continuous length measurement, to be made in comparison with the length of two reference specimens. These rigs consists of two main parts: the creep capsule including: specimens, loading bellow, microwave measuring apparatus, which is introduced into a standard gas gap furnace regulating the temperature by gas mixture and electrical heating

  13. 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 optim

  14. High-temperature oxide superconductors

    International Nuclear Information System (INIS)

    This paper reports that in the high-temperature oxide superconductors of the type Y(Ln)Ba2Cu3O7-δ, structure and oxygen stoichiometry play a crucial role. Thus, this family of high temperature oxide superconductors generally possesses the orthorhombic structure with two- as well as one-dimensional features. Oxygen stoichiometry in YBa2Cu3O7-δ has an important bearing on the structure as well as superconductivity. This is equally true in the La2-xBa2+xCu6O14+δ system of which only the 123 oxide (x = 1) with the orthorhombic structure shows high Tc. Orthorhombicity is also found in La2-x(Sr, Ba)xCuO4 superconductors of the K2NiF4 structure. Orthorhombicity is necessary for the formation of twins in Y(Ln)Ba2Cu3O7. Copper in these cuprates is only in 1+ and 2+ states, thereby making it necessary for oxygen holes to be present. The oxygen holes are responsible for superconductivity of the cuprates. High Tc superconductivity is also found in oxides of the Bi-(ca, SR)-Cu-O and Tl(Ca,Ba)-Cu-O systems of the general formula A2(M', M double-prime)n+1CunO2n+4 (A = Bi,Tl; M' = Ca; M double-prime = Sr,Ba) with Tc's in the range 80-125K depending on the number of Cu-O Layers

  15. Reduced bed temperature at thermo-chemical conversion of difficult fuels; Saenkt baeddtemperatur vid termokemisk omvandling av svaara braenslen

    Energy Technology Data Exchange (ETDEWEB)

    Niklasson, Fredrik; Haraldsson, Conny; Johansson, Andreas; Claesson, Frida; Baefver, Linda; Ryde, Daniel

    2010-05-15

    This work investigates the prospect of reducing the concentrations of alkali chlorides in the flue gas by lowering the temperature in the bottom zone of a fluidized bed (FB) furnace below the often used 850 deg C. The directive of a retention time of at least two seconds above 850 deg C is fulfilled by the raise of the flue gas temperature that follows the combustion of unburned gases at the point of injection of secondary and tertiary air, above the bottom bed zone. The aim of the present experiments is to determine the dependency between the temperature and the amount of alkali metals leaving the bottom bed for some selected waste and biomass fuels. The results are intended for plant owners as well as boiler manufacturers. The experiments were performed in an FB-reactor, which was externally heated to specific temperatures between 550 and 850 deg C. The reactor is made of a quartz glass tube with an inner diameter of 60 mm and a length of 1.2 m. The fluidized bed rests upon a porous plate of sintered quartz. The bed material used was 180 gram purified sea sand with particle sizes between 0.1 and 0.3 mm. The fluidizing gas was a mixture of nitrogen and air, introduced in the bottom of the reactor by mass flow controllers. At the outlet of the reactor, the flue gas was divided between conventional gas analyzers and an ICP-MS instrument. The gas flow to the ICP-MS instrument was cooled before a slip stream was sucked out via a capillary to a nebulizer from which the sample gas was led to the ICP-MS instrument. The function of the nebulizer is normally to form an aerosol of liquids, but here it was used solely as a pump. In addition, a known flow of krypton was added into the nebulizer to be used as an internal standard. The novel technique to measure the amount of alkali metals on-line from a batch fired FB-reactor has been shown to work in practice and to provide interesting results, which so far is qualitative only. Further development and calibration work is

  16. High Temperature Superconductor Accelerator Magnets

    CERN Document Server

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

    2016-11-10

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

  17. Faraday imaging at high temperatures

    International Nuclear Information System (INIS)

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

  18. METHOD OF CALCULATION OF THE NON-STATIONARY TEMPERATURE FIELD INSIDE OF THERMAL PACKED BED ENERGY STORAGE

    OpenAIRE

    Ermuratschii V.V.; Gritsay M.A

    2014-01-01

    e paper presents a method of the approximate calculation of the non-stationary temperature field inside of thermal packed bed energy storages with feasible and latent heat. Applying thermoelectric models and computational methods in electrical engineering, the task of computing non-stationary heat transfer is resolved with respect to third type boundary conditions without applying differential equations of the heat transfer. For sub-volumes of the energy storage the method is executed iterati...

  19. High Levels Of Bed Occupancy Associated With Increased Inpatient And Thirty-Day Hospital Mortality In Denmark

    DEFF Research Database (Denmark)

    Madsen, Flemming; Ladelund, Steen; Linneberg, Allan

    2014-01-01

    High bed occupancy rates have been considered a matter of reduced patient comfort and privacy and an indicator of high productivity for hospitals. Hospitals with bed occupancy rates of above 85 percent are generally considered to have bed shortages. Little attention has been paid to the impact...... of these shortages on patients' outcomes. We analyzed all 2.65 million admissions to Danish hospitals' departments of medicine in the period 1995-2012. We found that high bed occupancy rates were associated with a significant 9 percent increase in rates of in-hospital mortality and thirty-day mortality, compared...... to low bed occupancy rates. Being admitted to a hospital outside of normal working hours or on a weekend or holiday was also significantly associated with increased mortality. The health risks of bed shortages, including mortality, could be better documented as a priority health issue. Resources should...

  20. Multifunctional, High-Temperature Nanocomposites

    Science.gov (United States)

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

    2007-01-01

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

  1. METHOD OF CALCULATION OF THE NON-STATIONARY TEMPERATURE FIELD INSIDE OF THERMAL PACKED BED ENERGY STORAGE

    Directory of Open Access Journals (Sweden)

    Ermuratschii V.V.

    2014-04-01

    Full Text Available e paper presents a method of the approximate calculation of the non-stationary temperature field inside of thermal packed bed energy storages with feasible and latent heat. Applying thermoelectric models and computational methods in electrical engineering, the task of computing non-stationary heat transfer is resolved with respect to third type boundary conditions without applying differential equations of the heat transfer. For sub-volumes of the energy storage the method is executed iteratively in spatiotemporal domain. Single-body heating is modeled for each sub-volume, and modeling conditions are assumed to be identical for remained bod-ies, located in the same sub-volume. For each iteration step the boundary conditions will be represented by re-sults at the previous step. The fulfillment of the first law of thermodynamics for system “energy storage - body” is obtained by the iterative search of the mean temperature of the energy storage. Under variable boundary con-ditions the proposed method maybe applied to calculating temperature field inside of energy storages with packed beds consisted of solid material, liquid and phase-change material. The method may also be employed to compute transient, power and performance characteristics of packed bed energy storages.

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

    International Nuclear Information System (INIS)

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

  3. The Metabolic Cost of a High Intensity Exercise Program During Bed Rest

    Science.gov (United States)

    Hackney, Kyle; Everett, Meghan; Guined, Jamie; Cunningham, Daid

    2012-01-01

    Background: Given that disuse-related skeletal muscle atrophy may be exacerbated by an imbalance between energy intake and output, the amount of energy required to complete exercise countermeasures is an important consideration in the well being of subject health during bed rest and spaceflight. Objective: To evaluate the energy cost of a high intensity exercise program performed during short duration bed rest. Methods: 9 subjects (8 male and 1 female; 34.5 +/- 8.2 years) underwent 14 days of bed rest and exercise countermeasures. Exercise energy expenditure and excess post exercise oxygen consumption (EPOC) were collected once in each of 5 different exercise protocols (30 second, 2 minute and 4 minute intervals, continuous aerobic and a variety of resistance exercises) during bed rest. Body mass, basal metabolic rate (BMR), upper and lower leg muscle, subcutaneous, and intramuscular adipose tissue (IMAT) volumes were assessed before and at the end of bed rest. Results: There were no significant differences in body mass (pre: 75.1 +/- 10.5 kg; post: 75.2 +/- 10.1 kg), BMR (pre: 1649 +/- 216 kcal; post: 1657 +/- 177 kcal), muscle subcutaneous, or IMAT volumes (Table 2) after 14 days of bed rest and exercise. Body mass was maintained with an average daily intake of 2710 +/- 262 kcal (36.2 +/- 2.1 kcal/kg/day), while average daily energy expenditure was 2579 +/-311 kcal (34.5 +/- 3.6 kcal/kg/day). Exercise energy expenditure was significantly greater as a result of continuous aerobic exercise than all other exercise protocols.

  4. Accelerated carbonation of steelmaking slags in a high-gravity rotating packed bed

    International Nuclear Information System (INIS)

    Highlights: ► The carbonation conversion in a RPB was higher than that in traditional reactors. ► The optimum conditions were operated at 750 rpm and 65 °C for 30 min. ► The product on BOF slag was identified as crystallized calcite based on SEM and XRD. ► The diffusivity ranged from 10−7 to 10−6 cm2 s−1 based on the shrinking core model. - Abstract: Carbon dioxide (CO2) sequestration using the accelerated carbonation of basic oxygen furnace (BOF) slag in a high-gravity rotating packed bed (RPB) under various operational conditions was investigated. The effects of reaction time, reaction temperature, rotation speed and slurry flow rate on the CO2 sequestration process were evaluated. The samples of reacted slurry were analyzed quantitatively using thermogravimetric analysis (TGA) and atomic absorption spectrometry (AAS) and qualitatively using X-ray diffraction (XRD), scanning electron microscopy with energy-dispersive X-ray spectroscopy (SEM-EDX), and transmission electron microscopy (TEM). The sequestration experiments were performed at a liquid-to-solid ratio of 20:1 with a flow rate of 2.5 L min−1 of a pure CO2 stream under atmospheric temperature and pressure. The results show that a maximum conversion of BOF slag was 93.5% at a reaction time of 30 min and a rotation speed of 750 rpm at 65 °C. The experimental data were utilized to determine the rate-limiting mechanism based on the shrinking core model (SCM), which was validated by the observations of SEM and TEM. Accelerated carbonation in a RPB was confirmed to be a viable method due to its higher mass-transfer rate.

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

    Science.gov (United States)

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

    2014-01-01

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

  6. High-Temperature Resistance Strain Gauges

    Science.gov (United States)

    Lei, Jih-Fen

    1994-01-01

    Resistance strain gauges developed for use at high temperatures in demanding applications like testing aircraft engines and structures. Measures static strains at temperatures up to 800 degrees C. Small and highly reproducible. Readings corrected for temperature within small tolerances, provided temperatures measured simultaneously by thermocouples or other suitable devices. Connected in wheatstone bridge.

  7. Reduced Bed Temperature in FB-Boilers Burning Waste - part II; Saenkt baeddtemperatur i FB-pannor foer avfallsfoerbraenning - etapp 2

    Energy Technology Data Exchange (ETDEWEB)

    Niklasson, Fredrik; Pettersson, Anita; Claesson, Frida; Johansson, Andreas; Gunnarsson, Anders; Gyllenhammar, Marianne; Victoren, Anders; Gustafsson, Goeran

    2010-07-01

    This project focuses on evaluating whether lowered bed temperature in FB-boilers for waste combustion gives operational benefits, such as reduced fouling in the convection pass. If so, this mode of operation could reduce the number of unplanned boiler outages, reduce the need for soot blowing, and extend the lifetime of the superheaters at unaltered steam temperature. The project is based on full-scale experiments performed at Ryaverket in Boraas. The plant has two waste-fired 20 MW{sub t} FB-boilers. The study is based on a comparison between operational data and measurement results from two different operating conditions of the boilers. In addition to the data that normally are logged by the control system, samples of fuel, ashes, particles, and deposits were taken and subsequently analyzed. The structure of the bed ash was altered by lowering the bed temperature. Under normal boiler operation, the bed ash contains many small agglomerates that disappeared when the bed temperature was lowered. Due to this, the sand consumption of the plant could be reduced by roughly 25 %. At lowered bed temperature, the concentration of chlorine increased in the bed ash and in the recycled sand while it decreased in the ashes from the cyclone and fabric filter. The concentration of HCl in the flue gas increased as the bed temperature was lowered. This is considered a consequence of less chlorine forming alkali chlorides. Moreover, the particle measurements showed that the amount of submicron particles decreased during lowered bed temperature, which also is an indication of less alkali chlorides in the flue gas. The deposit probes showed an approximate 20 % reduction of the fouling rate when the bed temperature was lowered from 876 to 714 deg C. The chlorine content also decreased in the deposits. For the deposit probes at 500 deg C, (corresponds to a steam temperature of 465 deg C) significant amounts of KCl were found in the deposits, even when the bed temperature was lowered

  8. High Temperature Superconducting Underground Cable

    Energy Technology Data Exchange (ETDEWEB)

    Farrell, Roger, A.

    2010-02-28

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

  9. High-temperature borehole instrumentation

    Energy Technology Data Exchange (ETDEWEB)

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

    1985-10-01

    A new method of extracting natural heat from the earth's crust was invented at the Los Alamos National Laboratory in 1970. It uses fluid pressures (hydraulic fracturing) to produce cracks that connect two boreholes drilled into hot rock formations of low initial permeability. Pressurized water is then circulated through this connected underground loop to extract heat from the rock and bring it to the surface. The creation of the fracture reservior began with drilling boreholes deep within the Precambrian basement rock at the Fenton Hill Test Site. Hydraulic fracturing, flow testing, and well-completion operations required unique wellbore measurements using downhole instrumentation systems that would survive the very high borehole temperatures, 320/sup 0/C (610/sup 0/F). These instruments were not available in the oil and gas industrial complex, so the Los Alamos National Laboratory initiated an intense program upgrading existing technology where applicable, subcontracting materials and equipment development to industrial manufactures, and using the Laboratory resource to develop the necessary downhole instruments to meet programmatic schedules. 60 refs., 11 figs.

  10. Effect of temperature and dolomite on tar formation during gasification of torrefied biomass in a pressurized fluidized bed

    International Nuclear Information System (INIS)

    This work investigates the effect of temperature and bed material on the yields and composition of gas and tar produced from gasification of two types of biomass feedstock previously torrefied at 275 °C. Special attention was devoted to the evolution of tar composition under the different experimental conditions. Experiments were conducted in a fluidized bed reactor using two different types of bed material (sand and dolomite) under a constant pressure of 0.5 MPa and at two temperature levels (750 and 850 °C). Tar destruction reactions promoted by the catalyst (dolomite) enhanced the production of some of the gas components (H2, CO2, CO and CH4) whereas C2 hydrocarbons decreased, this effect being slightly more relevant at 850 °C. Comparable trends were observed with increasing temperature, which had a positive effect on cracking reactions and tar destruction. For both feedstocks, the increase in temperature resulted in (i) higher gas yields, and (ii) enhanced char gasification rate. On the other hand the evolution of tar yield and composition revealed a possible competition between two tar reaction pathways during gasification, (i) tar polymerization, and (ii) de-alkylation, dehydration and cracking of tars, depending on the experimental conditions and feedstock used. - Highlights: • An experimental study of pressurized gasification of torrefied biomass is presented. • Special attention was devoted to the evolution of tar composition. • Increasing temperature and dolomite presence led to higher gas and lower tar yields. • Tar evolution revealed a possible competition between two tar reaction pathways

  11. Geothermal: surface geothermal, low temperature geothermal, high temperature geothermal, stimulation-based high temperature geothermal

    International Nuclear Information System (INIS)

    For the different geothermal energy technologies (as a whole, surface, low temperature, high temperature, and stimulated high temperature), this document proposes: brief definitions and descriptions of principle and operation, challenges and stakes regarding energy production, major actors in the World in terms of installed power and in France in terms of committed organisations, measurement units and key figures, typical locations, past and present exploitation, and future perspectives. Thus technologies like heat pumps or Canadian well among others, their strengths and weaknesses, and their use in electricity production are evoked

  12. 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.

  13. 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

  14. High temperature nuclear heat for isothermal reformer

    International Nuclear Information System (INIS)

    High temperature nuclear heat can be used to operate a reformer with various feedstock materials. The product synthesis gas can be used not only as a source for hydrogen and as a feedstock for many essential chemical industries, such as ammonia and other products, but also for methanol and synthetic fuels. It can also be burnt directly in a combustion chamber of a gas turbine in an efficient combined cycle and generate electricity. In addition, it can be used as fuel for fuel cells. The reforming reaction is endothermic and the contribution of the nuclear energy to the calorific value of the final product (synthesis gas) is about 25%, compared to the calorific value of the feedstock reactants. If the feedstock is from fossil origin, the nuclear energy contributes to a substantial reduction in CO2 emission to the atmosphere. The catalytic steam reforming of natural gas is the most common process. However, other feedstock materials, such as biogas, landfill gas and CO2-contaminated natural gas, can be reformed as well, either directly or with the addition of steam. The industrial steam reformers are generally fixed bed reactors, and their performance is strongly affected by the heat transfer from the furnace to the catalyst tubes. In top-fired as well as side-fired industrial configurations of steam reformers, the radiation is the main mechanism of heat transfer and convection heat transfer is negligible. The flames and the furnace gas constitute the main sources of the heat. In the nuclear reformers developed primarily in Germany, in connection with the EVA-ADAM project (closed cycle), the nuclear heat is transferred from the nuclear reactor coolant gas by convection, using a heating jacket around the reformer tubes. In this presentation it is proposed that the helium in a secondary loop, used to cool the nuclear reactor, will be employed to evaporate intermediate medium, such as sodium, zinc and aluminum chloride. Then, the vapors of the medium material transfer

  15. High School Students’ Use of Sunscreen and Tanning Beds

    Centers for Disease Control (CDC) Podcasts

    2014-08-20

    This podcast is an interview with Corey Basch, EdD, MPH, assistant professor in the Department of Public Health at William Paterson University. Dr. Basch discusses her study on high school students’ use of sunscreen and tanning beds between 2001 and 2011.  Created: 8/20/2014 by Preventing Chronic Disease (PCD), National Center for Chronic Disease Prevention and Health Promotion (NCCDPHP).   Date Released: 8/20/2014.

  16. Is inversion based high resolution characterization of spatially heterogeneous river bed hydraulic conductivity needed and possible?

    Directory of Open Access Journals (Sweden)

    W. Kurtz

    2013-05-01

    Full Text Available River-aquifer exchange fluxes influence local and regional water balances and affect groundwater and river water quality and quantity. Unfortunately, river-aquifer exchange fluxes tend to be strongly spatially variable and it is an open research question to which degree river bed heterogeneity has to be represented in a~model in order to achieve reliable estimates of river-aquifer exchange fluxes. This research question is addressed in this paper with help of synthetic simulation experiments, which mimic the Limmat aquifer in Zurich (Switzerland, where river-aquifer exchange fluxes and groundwater management activities play an important role. The solution of the unsaturated-saturated subsurface hydrological flow problem including river-aquifer interaction is calculated for ten different synthetic realities where the strongly heterogeneous river bed hydraulic conductivities (L are perfectly known. Hydraulic head data (100 in the default scenario are sampled from the synthetic realities. In subsequent data assimilation experiments, where L is unknown now, the hydraulic head data are used as conditioning information, with help of the Ensemble Kalman Filter (EnKF. For each of the ten synthetic realities, four different ensembles of L are tested in the experiments with EnKF; one ensemble estimates high resolution L-fields with different L values for each element, and the other three ensembles estimate effective L values for 5, 3 or 2 zones. The calibration of higher resolution L-fields (i.e., fully heterogeneous or 5 zones gives better results than the calibration of L for only 3 or 2 zones in terms of reproduction of states, stream-aquifer exchange fluxes and parameters. Effective L for a limited number of zones cannot always reproduce the true states and fluxes well and results in biased estimates of net exchange fluxes between aquifer and stream. Also in case only 10 head data are used for conditioning, the high resolution L-fields outperform the

  17. Advanced high temperature heat flux sensors

    Science.gov (United States)

    Atkinson, W.; Hobart, H. F.; Strange, R. R.

    1983-01-01

    To fully characterize advanced high temperature heat flux sensors, calibration and testing is required at full engine temperature. This required the development of unique high temperature heat flux test facilities. These facilities were developed, are in place, and are being used for advanced heat flux sensor development.

  18. High levels of bed occupancy associated with increased inpatient and thirty-day hospital mortality in Denmark.

    Science.gov (United States)

    Madsen, Flemming; Ladelund, Steen; Linneberg, Allan

    2014-07-01

    High bed occupancy rates have been considered a matter of reduced patient comfort and privacy and an indicator of high productivity for hospitals. Hospitals with bed occupancy rates of above 85 percent are generally considered to have bed shortages. Little attention has been paid to the impact of these shortages on patients' outcomes. We analyzed all 2.65 million admissions to Danish hospitals' departments of medicine in the period 1995-2012. We found that high bed occupancy rates were associated with a significant 9 percent increase in rates of in-hospital mortality and thirty-day mortality, compared to low bed occupancy rates. Being admitted to a hospital outside of normal working hours or on a weekend or holiday was also significantly associated with increased mortality. The health risks of bed shortages, including mortality, could be better documented as a priority health issue. Resources should be allocated to researching the causes and effects of bed shortages, with the aim of creating greater interest in exploring new methods to avoid or reduce bed shortages. PMID:25006151

  19. 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.

  20. Resonance integral calculations for high temperature reactors

    International Nuclear Information System (INIS)

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

  1. Design and Development of a High Efficiency CarbonGranular Bed Filter in Industrial Scale

    Institute of Scientific and Technical Information of China (English)

    张济宇; 旷戈; 林诚

    2004-01-01

    The new dust removal technical route using the carbon-granular bed filter, packed of carbon particles with appropriate grade derive from an online-process vibration sieve, to replace the traditional baggy filter had been developed successfully for capturing the micro-carbon dusts produced from pulverization of petroleum coke,and the green close loop of carbon materials is thus completed in the combined pulverizing and classifying system and pulverized carbon dust removal process. The high dust removal efficiency greater than 99%, low outlet dust concentration less than 100 mg-m-S, low pressure drop through dust filtration chamber less than 980 Pa, simple and easy design, and flexible and stable operation were achieved also with the carbon-granular bed filter in both bench and industrial scale operations.

  2. Melt granulation of pharmaceutical powders: a comparison of high-shear mixer and fluidised bed processes.

    Science.gov (United States)

    Passerini, Nadia; Calogerà, Giacomo; Albertini, Beatrice; Rodriguez, Lorenzo

    2010-05-31

    The main aim of this research was to compare in situ melt granulation process in high-shear mixers and fluidised bed equipments with particular attention to the final properties of granules. In addition, the study evaluated the suitability of melt granulation in fluidised bed for improving the dissolution rate of drugs. Agglomerates having identical composition (10%, w/w, of ibuprofen or ketoprofen, 20%, w/w, of PEG 6000 and 70%, w/w, of lactose monohydrate) were produced using both equipments and their morphology, particle size, flowability, friability, drug loading, dissolution behaviors at pH 1.2 and 7.4 and physicochemical properties (DSC and XRD analysis) have been evaluated and compared. The results showed that melt granulation can be successfully performed in both granulators. The utilization of a different equipment had strong impact on the particle size distribution of the granules and on their morphology, while the effect on others physical properties was little, as all the granules possess low friability and excellent flowability. Moreover both the solid state characteristics of the products and the dissolution behaviors of ibuprofen and ketoprofen granules were found to be practically independent of the equipment and all granules showed a significant increase of the drug dissolution rate in acidic conditions. In conclusion in situ melt granulation in fluidised beds could be considered a suitable alternative to the melt granulation in high-shear mixers. PMID:20214959

  3. High temperature tensile testing of ceramic composites

    Science.gov (United States)

    Gyekenyesi, John Z.; Hemann, John H.

    1988-01-01

    The various components of a high temperature tensile testing system are evaluated. The objective is the high temperature tensile testing of SiC fiber reinforced reaction bonded Si3N4 specimens at test temperatures up to 1650 C (3000 F). Testing is to be conducted in inert gases and air. Gripping fixtures, specimen configurations, furnaces, optical strain measuring systems, and temperature measurement techniques are reviewed. Advantages and disadvantages of the various techniques are also noted.

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

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen

    2007-01-01

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

  5. High-temperature protective coatings on superalloys

    Institute of Scientific and Technical Information of China (English)

    刘培生; 梁开明; 周宏余

    2002-01-01

    Protective coatings are essential for superalloys to serve as blades of gas turb ines at high temperatures, and they primarily include aluminide coating, MCrAlY overlay coating, thermal barrier coating and microcrystalline coating. In this paper, all these high-temperature coatings are reviewed as well as their preparing techniques. Based on the most application and the main failure way, the importance is then presented for further deepgoing study on the high-temperature oxidation law of aluminide coatings.

  6. A high temperature fuel element

    Energy Technology Data Exchange (ETDEWEB)

    Sekido, A.; Nakai, M.; Ninomiya, Y.

    1982-12-21

    A solid electrolyte which conducts electricity with heating by oxygen ions and operates at a temperature of 1,000C is used in the element. The cathode, besides the ionic conductivity in oxygen, has an electron conductivity. The anode has electron conductivity. Substances such as Bi203, into which oxides of alkaline earth metals are added, are used for making the cathode. The electrolyte consists of ZrO2 and Y2O3, to which CaO is added. WC, to which an H2 type fuel is fed, serves as the anode. The element has a long service life.

  7. High Performance Cascading Adsorption Refrigeration Cycle with Internal Heat Recovery Driven by a Low Grade Heat Source Temperature

    OpenAIRE

    Yuki Ueda; Atsushi Akisawa; Aep Saepul Uyun; Takahiko Miyazaki

    2009-01-01

    This paper presents the performance of an advanced cascading adsorption cycle that utilizes a driven heat source temperature between 90–130 ºC. The cycle consists of four beds that contain silica gel as an adsorber fill. Two of the beds work in a single stage cycle that is driven by an external heat source, while the other two beds work in a mass recovery cycle that is driven by waste heat of sensible and adsorption heat of the high temperature cycle. The performances, in terms of the coef...

  8. 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

  9. 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

  10. Novel High Temperature Strain Gauge Project

    Data.gov (United States)

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

  11. High Temperature Capacitors for Venus Exploration Project

    Data.gov (United States)

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

  12. Long-term and high resolution measurements of bed level changes in a temperate, microtidal coastal lagoon

    DEFF Research Database (Denmark)

    Andersen, Thorbjørn J.; Pejrup, Morten; Nielsen, Allan Aasbjerg

    2006-01-01

    This study presents the results of a long-term monitoring program of bed level changes measured during 8 yr at an intertidal mudflat in a microtidal, temperate coastal lagoon. Additionally, bed level measurements obtained at a 10-min temporal resolution at the same tidal flat and at the bed of a ...... seriously threatened by the expected sea level rise in the 21st century.......This study presents the results of a long-term monitoring program of bed level changes measured during 8 yr at an intertidal mudflat in a microtidal, temperate coastal lagoon. Additionally, bed level measurements obtained at a 10-min temporal resolution at the same tidal flat and at the bed of a...... nearby tidal channel are presented. Short-term changes in bed level are one or two orders of magnitude larger than the annual net-deposition rate, which shows that the environment is highly dynamic with respect to erosion, transport and deposition of fine-grained sediment. Some seasonality in the bed...

  13. High resolution ice thickness, bed topography, and roughness of a land terminating section of the western Greenland Ice Sheet

    DEFF Research Database (Denmark)

    Lindback, K.; Pettersson, R.; Doyle, S. H.;

    above sea level. The bed topography shows an intricate subglacial trough system, resembling the landscape in the proglacial area. We also calculate the hydraulic potential to get a proxy of the subglacial routing of water in the area. To analyse the geomorphological conditions of the bed, we calculated...... velocities also coincide with an overdeepened trough system in the northern parts of the area; an area where active smoothing could be taking place. The southern parts consist of high bed elevations and have generally high roughness values; the bedrock likely consists of hard unreworked orthogneiss...

  14. 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

  15. High Temperature Calcination - MACT Upgrade Equipment Pilot Plant Test

    Energy Technology Data Exchange (ETDEWEB)

    Richard D. Boardman; B. H. O& #39; Brien; N. R. Soelberg; S. O. Bates; R. A. Wood; C. St. Michel

    2004-02-01

    About one million gallons of acidic, hazardous, and radioactive sodium-bearing waste are stored in stainless steel tanks at the Idaho Nuclear Technology and Engineering Center (INTEC), which is a major operating facility of the Idaho National Engineering and Environmental Laboratory. Calcination at high-temperature conditions (600 C, with alumina nitrate and calcium nitrate chemical addition to the feed) is one of four options currently being considered by the Department of Energy for treatment of the remaining tank wastes. If calcination is selected for future processing of the sodium-bearing waste, it will be necessary to install new off-gas control equipment in the New Waste Calcining Facility (NWCF) to comply with the Maximum Achievable Control Technology (MACT) standards for hazardous waste combustors and incinerators. This will require, as a minimum, installing a carbon bed to reduce mercury emissions from their current level of up to 7,500 to <45 {micro}g/dscm, and a staged combustor to reduce unburned kerosene fuel in the off-gas discharge to <100 ppm CO and <10 ppm hydrocarbons. The staged combustor will also reduce NOx concentrations of about 35,000 ppm by 90-95%. A pilot-plant calcination test was completed in a newly constructed 15-cm diameter calciner vessel. The pilot-plant facility was equipped with a prototype MACT off-gas control system, including a highly efficient cyclone separator and off-gas quench/venturi scrubber for particulate removal, a staged combustor for unburned hydrocarbon and NOx destruction, and a packed activated carbon bed for mercury removal and residual chloride capture. Pilot-plant testing was performed during a 50-hour system operability test January 14-16, followed by a 100-hour high-temperature calcination pilot-plant calcination run January 19-23. Two flowsheet blends were tested: a 50-hour test with an aluminum-to-alkali metal molar ratio (AAR) of 2.25, and a 50-hour test with an AAR of 1.75. Results of the testing

  16. Nuclear fuels for very high temperature applications

    Energy Technology Data Exchange (ETDEWEB)

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

    1992-08-01

    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{sub 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.

  17. Nuclear fuels for very high temperature applications

    International Nuclear Information System (INIS)

    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 UO2 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

  18. Nuclear fuels for very high temperature applications

    Energy Technology Data Exchange (ETDEWEB)

    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{sub 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.

  19. Spin Hall magnetoresistance at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Uchida, Ken-ichi, E-mail: kuchida@imr.tohoku.ac.jp [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); PRESTO, Japan Science and Technology Agency, Saitama 332-0012 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); Qiu, Zhiyong [Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Kikkawa, Takashi; Iguchi, Ryo [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); Saitoh, Eiji [Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); Spin Quantum Rectification Project, ERATO, Japan Science and Technology Agency, Sendai 980-8577 (Japan); WPI Advanced Institute for Materials Research, Tohoku University, Sendai 980-8577 (Japan); CREST, Japan Science and Technology Agency, Tokyo 102-0076 (Japan); Advanced Science Research Center, Japan Atomic Energy Agency, Tokai 319-1195 (Japan)

    2015-02-02

    The temperature dependence of spin Hall magnetoresistance (SMR) in Pt/Y{sub 3}Fe{sub 5}O{sub 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.

  20. Axial Changes of Catalyst Structure and Temperature in a Fixed-Bed Microreactor During Noble Metal Catalysed Partial Oxidation of Methane

    DEFF Research Database (Denmark)

    Hannemann, S.; Grunwaldt, Jan-Dierk; Kimmerle, B.;

    2009-01-01

    -heating by the exothermic methane oxidation was too strong. The results indicate that in the oxidized zone mainly combustion of methane occurs, whereas in the reduced part direct partial oxidation and reforming reactions prevail. The results demonstrate how spatially resolved spectroscopy can help in understanding......-line mass spectrometry. This experimental strategy allowed collecting data on the structure of the noble metal (oxidation state) and the temperature along the catalyst bed. The reaction was investigated in a fixed-bed quartz microreactor (1-1.5 mm diameter) following the catalytic performance by on-line gas...... catalytic reactions involving different reaction zones and gradients even in micro scale fixed-bed reactors....

  1. Recrystallization of high temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

    Kouzoudis, D.

    1996-05-09

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

  2. High Temperature Solid State Lithium Battery Project

    Data.gov (United States)

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

  3. Lightweight, High-Temperature Radiator Panels Project

    Data.gov (United States)

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

  4. High Temperature Rechargeable Battery Development Project

    Data.gov (United States)

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

  5. The effects of fabric for sleepwear and bedding on sleep at ambient temperatures of 17°C and 22°C

    OpenAIRE

    Shin, Mirim; Halaki, Mark; Swan, Paul; Ireland, Angus H; Chow, Chin Moi

    2016-01-01

    The fibers used in clothing and bedding have different thermal properties. This study aimed to investigate the influences of textile fabrics on sleep under different ambient temperature (T a) conditions. Seventeen healthy young participants (ten males) underwent nine nights of polysomnography testing including an adaptation night. Participants were randomized to each of the three binary factors: sleepwear (cotton vs wool), bedding (polyester vs wool), and T a (17°C vs 22°C with relative humid...

  6. High temperature nonplanar laminates. Progress report

    Energy Technology Data Exchange (ETDEWEB)

    Stein, J.D.

    1977-03-01

    Development of high temperature substrates was initiated to fabricate nonplanar laminates. Forming of readily available polyimide and fluorocarbon films was established, and the evaluation of thermal stability up to 500/sup 0/F (260/sup 0/C) initiated. The development of auxiliary materials suitable for high temperature system applications and specific adhesive evaluation is included.

  7. Sludge Bed Granules’ Growth in the HUASB Reactor Treating High Strength Industrial Wastewater

    Directory of Open Access Journals (Sweden)

    Sinan Abood Habeeb

    2014-12-01

    Full Text Available The development of anaerobic sludge granules in a hybrid up-flow anaerobic sludge bed (HUASB reactor in terms of granular size and solids content was observed. After appropriate pre-treatment of the palm oil mill effluent (POME, it was continuously fed to the HUASB reactor under room temperature condition (27°C.  Particle size analysis and solids content examination were conducted for 196 days. A volatile solid ratio was ranging from 0.36 to 0.51 which was quite low, and granules particle size of less than 1 mm diameter was reported during the operating period. Results obtained in this study indicated that sludge bed development based on the sludge particle size distribution and the volatile solid ratio, was quite slow due to the bulk solids that entering the reactor resulting in certain inhibition of the anaerobes’ activity. It has been concluded that anaerobic wastewater treatment process in anaerobic reactors such as the HUASB reactor, can be significantly affected by the organic loading rate, hydraulic retention time applied to the reactor and the wastewater characteristics.

  8. High temperature reactor development in the Netherlands

    International Nuclear Information System (INIS)

    This year, some clear design choices have been made in the WHITE Reactor development programme. The activities will be concentrated at the development of a small size pebble bed HTR for combined heat and power production with a closed cycle gas turbine. Objective of the development is threefold: 1. restoring social support; 2. establishing commercial viability after market introduction; and 3. making the market introduction itself feasible, i.e. limited development and first-of-a-kind costs. This design is based on the peu-a-peu design of KFA Juelich and will be optimized. The computer codes necessary for this are being prepared for this work. The dynamic neutronics code PANTHER is being coupled to the thermal hydraulics code THERMIX-DIREKT. For this reactor type, fuel temperatures are maximal in the scenario of depressurization with recriticality. Even for this scenario, fuel temperatures of the 20MWth PAP-GT do not exceed 1300 deg. C, so there should be room for upscaling for economic reasons. On the other hand, it would be convenient to fuel the reactor batchwise instead of continuously, and the use of thorium could be required. These two features may lead to a larger temperature margin. The optimal design must unite these features in the best acceptable way. To gain expertise in calculations on gas cooled graphite moderate reactors, benchmark calculations are being performed in parallel with international partners. Parallel to this, special expertise is being built up on HTR fuel and HTR reactor vessels. (author). 3 refs

  9. Thermodynamic Foundation for High Temperature Electrochemistry

    Institute of Scientific and Technical Information of China (English)

    ZHANG W.; E. A. Charles; J. Congleton

    2004-01-01

    Thermodynamic concepts required for the thermodynamic calculation of the potentials of electrodes for high temperature applications are briefly reviewed. A thermodynamic approach to the calculation of half cell potentials and the standard chemical potential of an electron at high temperatures which are related to the Standard Hydrogen Electrode(SHE) is discussed. As examples, an external Ag/AgCl reference electrode and a YSZ (Ag |O2) pH sensor for high temperature applications are analyzed by using the thermodynamic approach to derive a high temperature pH measurement equation. The two electrodes are employed to measure high temperature pH and the measured pH was compared with the calculated pH by using a solution chemistry method. Concepts and principles for electrode kinetics are also briefly introduced and a modification to the Tafel equations is suggested.

  10. Fluid-bed process for SYNROC production

    International Nuclear Information System (INIS)

    SYNROC is a titanate-based ceramic waste developed for the immobilization of high-level nuclear reactor waste. Lawrence Livermore National Laboratory (LLNL) has investigated a fluid-bed technique for the large-scale production of SYNROC precursor powders. Making SYNROC in a fluid bed permits slurry drying, calcination and reduction-oxidation reactions to be carried out in a single unit. We present the results of SYNROC fluid-bed studies from two fluid-bed units 10 cm in diameter: an internally heated fluid-bed unit developed by Exxon Idaho and an externally heated unit constructed at LLNL. Bed operation over a range of temperatures, feed rates, fluidizing rates, and redox conditions indicate that SYNROC powders of a high density and a uniform particle size can be produced. These powders facilitate the densification step and yield dense ceramics (greater than 95% theoretical density) with well-developed phases and low leaching rates

  11. Is high-resolution inverse characterization of heterogeneous river bed hydraulic conductivities needed and possible?

    Directory of Open Access Journals (Sweden)

    W. Kurtz

    2013-10-01

    Full Text Available River–aquifer exchange fluxes influence local and regional water balances and affect groundwater and river water quality and quantity. Unfortunately, river–aquifer exchange fluxes tend to be strongly spatially variable, and it is an open research question to which degree river bed heterogeneity has to be represented in a model in order to achieve reliable estimates of river–aquifer exchange fluxes. This research question is addressed in this paper with the help of synthetic simulation experiments, which mimic the Limmat aquifer in Zurich (Switzerland, where river–aquifer exchange fluxes and groundwater management activities play an important role. The solution of the unsaturated–saturated subsurface hydrological flow problem including river–aquifer interaction is calculated for ten different synthetic realities where the strongly heterogeneous river bed hydraulic conductivities (L are perfectly known. Hydraulic head data (100 in the default scenario are sampled from the synthetic realities. In subsequent data assimilation experiments, where L is unknown now, the hydraulic head data are used as conditioning information, with the help of the ensemble Kalman filter (EnKF. For each of the ten synthetic realities, four different ensembles of L are tested in the experiments with EnKF; one ensemble estimates high-resolution L fields with different L values for each element, and the other three ensembles estimate effective L values for 5, 3 or 2 zones. The calibration of higher-resolution L fields (i.e. fully heterogeneous or 5 zones gives better results than the calibration of L for only 3 or 2 zones in terms of reproduction of states, stream–aquifer exchange fluxes and parameters. Effective L for a limited number of zones cannot always reproduce the true states and fluxes well and results in biased estimates of net exchange fluxes between aquifer and stream. Also in case only 10 head data are used for conditioning, the high

  12. Sand attrition in conical spouted beds

    Institute of Scientific and Technical Information of China (English)

    Aranzazu R. Fernández-Akarregui; Jon Makibar; Isabel Alava; Luis Diaz; Fernando Cueva; Roberto Aguado; Gartzen Lopez; Martin Olazar

    2012-01-01

    A study was carried out on the attrition in conical spouted beds using two sands with different properties for several bed heights and gas flow rates.Furthermore,the influence of a draft tube was studied at ambient and high temperatures.The main objective was to acquire knowledge on the attrition of sand beds for biomass pyrolysis in a pilot plant provided with a conical spouted bed reactor.A first-order kinetic equation is proposed for sand attrition in a conical spouted bed at room temperature.The predicted attrition rate constant depends exponentially on excess air velocity over that for minimum spouting.Both the draft tube and temperature increase contribute to reduction of attrition.

  13. Ecological observations of major Salicornia beds from highly saline coastal wetlands of India

    Digital Repository Service at National Institute of Oceanography (India)

    Jagtap, T.G.; Bhosale, S.H.; Nagle, V.L.

    Extensive Salicornia beds along the Gulf of Kutchchh (northwest) and Tamilnadu (southeast) coasts were investigated with respect to vegetative structure and ambient environmental conditions. The width of the beds varied from approximately 5 m...

  14. Preliminary safety analysis of a thorium high-conversion pebble bed reactor

    International Nuclear Information System (INIS)

    An inherently safe thorium High-Conversion Pebble Bed Reactor would combine the inherent safety characteristics of the Pebble Bed Reactor with the favourable waste characteristics and resource availability of the thorium fuel cycle. Previous work by the authors showed that high conversion ratio's can be achieved within a thorium Pebble Bed Reactor (PBR) at a practical operating regime. The thorium PBR core design consists of a cylindrical core with a central driver zone surrounded by a breeder zone. The breeder pebbles have a 30 g heavy metal (HM) loading to enhance conversion of Th-232 into U-233, while the driver pebbles (10 w% U-233) contain a lower metal loading to enhance fission. In previous studies, thorium PBR designs were presented for three core diameters, using a 7.5 g heavy metal (HM) loading for the driver pebbles. The current paper investigates the safety of these thorium PBR designs in terms of reactivity coefficients and possible reactivity insertion due to water ingress. Early results indicated that the values of the reactivity coefficients for the three designs with 7.5 g HM loading per driver pebble were rather small and the possible reactivity insertion due to water ingress was very large. Therefore, also a lower HM loading per driver pebble (4 g) was investigated to reduce the impact of water ingress, since the core becomes less under-moderated. For the three core diameters investigated, it is shown that reducing the metal loading in the driver pebbles to 4 g is indeed advantageous in terms of safety, water ingress leads to a smaller reactivity increase but also the reactivity coefficients become stronger negative. Secondly, the breeding performance of the cores with a 4 g driver pebble HM loading improves. On the downside, the driver pebble residence times become shorter, which could increase fuel reprocessing costs. Fuel pebbles would have to be recycled at an increased rate, which might be more challenging from a practical perspective

  15. Removal of phenol by activated alumina bed in pulsed high-voltage electric field

    Institute of Scientific and Technical Information of China (English)

    ZHU Li-nan; MA Jun; YANG Shi-dong

    2007-01-01

    A new process for removing the pollutants in aqueous solution-activated alumina bed in pulsed high-voltage electric field was investigated for the removal of phenol under different conditions. The experimental results indicated the increase in removal rate with increasing applied voltage, increasing pH value of the solution, aeration, and adding Fe2+. The removal rate of phenol could reach 72.1 % when air aeration flow rate was 1200 ml/min, and 88.2 % when 0.05 mmol/L Fe2+ was added into the solution under the conditions of applied voltage 25 kV, initial phenol concentration of 5 mg/L, and initial pH value 5.5. The addition of sodium carbonate reduced the phenol removal rate. In the pulsed high-voltage electric field, local discharge occurred at the surface of activated alumina, which promoted phenol degradation in the thin water film. At the same time, the space-time distribution of gas-liquid phases was more uniform and the contact areas of the activated species generated from the discharge and the pollutant molecules were much wider due to the effect of the activated alumina bed. The synthetical effects of the pulsed high-voltage electric field and the activated alumina particles accelerated phenol degradation.

  16. A batteryless temperature sensor based on high temperature sensitive material

    Science.gov (United States)

    Bakkali, Asma; Pelegri-Sebastia, José; Laghmich, Youssef; Lyhyaoui, Abdelouahid

    2016-05-01

    The major challenge in wireless sensor networks is the reduction of energy consumption. Passive wireless sensor network is an attractive solution for measuring physical parameters in harsh environment for large range of applications requiring sensing devices with low cost of fabrication, small size and long term measurement stability. Batteryless temperature sensing techniques are an active research field. The approach developed in our work holds a promising future for temperature sensor applications in order to successfully reduce the energy consumption. The temperature sensor presented in this paper is based on the electromagnetic transduction principle using the integration of the high temperature sensitive material into a passive structure. Variation in temperature makes the dielectric constant of this material changing, and such modification induces variation in the resonant frequencies of high-Q whispering-gallery modes (WGM) in the millimeter-wave frequency range. Following the results achieved, the proposed device shows a linear response to the increasing temperature and these variations can be remotely detected from a radar interrogation. Contribution to the topical issue "Materials for Energy Harvesting, Conversion and Storage (ICOME 2015) - Elected submissions", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

  17. A high temperature granulation process for ecological ash recirculation

    Energy Technology Data Exchange (ETDEWEB)

    Sundqvist, Thomas

    1999-07-01

    This thesis is a summary of three papers dealing with new technologies for facilitating ecological biomass ash recirculation back to forest and farm lands. The present outtake of biomass for paper and energy production may be incompatible with a sustainable forestry. The cycle of nutrients contained in the biomass extracted must be closed by ash recirculation in an environmental compatible way. This implies stabilization of the loose ashes/rest-products to a product with low heavy metal contents, controlled leaching properties and a high spreadability. In the present work, two different techniques were evaluated for the possibilities to separate heavy metals from the nutrient elements by utilizing high process temperatures to vaporize the unwanted metals from the condensed bulk materials. The results indicated that direct in-situ separation in fluidized bed combustion systems is possible, but requires too high process temperatures to be practically attractive. On the other hand, the new proposed high temperature treatment method for granulated raw materials was found to significantly separate As, Cd and Pb, with separation efficiencies exceeding 90 % at optimal operating conditions. In addition, the results indicated that the treatment method could be used to significantly delay and control the leaching characteristics, as well as the content of products of incomplete combustion of the produced granules.

  18. 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...

  19. Determination of the effective thermal diffusivity in a porous bed containing rice grains: effects of moisture content and temperature

    Science.gov (United States)

    Dotto, G. L.; Pinto, L. A. A.; Moreira, M. F. P.

    2016-04-01

    The effective thermal diffusivity ( α ef ) of a porous bed containing rice grains was determined under different experimental conditions. The α ef values were estimated by the Log method. The effects of rice moisture content (2, 12 and 22 % w.b.) and temperature (15, 35, 55 and 75 °C) on the α ef values were investigated. Finally, an empirical model was proposed to represent the effective thermal diffusivity as a function of the moisture content ( X) and temperature ( T). The results revealed that the increase in the rice moisture content and temperature caused an increase in α ef values, which ranged from 0.91 × 10-7 to 3.23 × 10-7 m2 s-1. In the studied range, the dependence of α ef with the rice moisture content and temperature can be represented as: α ef (m2s-1) = (0.63 + 5.63 × 10-2 X + 1.51 × 10-2 T + 1.17 × 10-4 XT) × 10-7. The proposed empirical model was suitable to predict the α ef values with mean absolute percentage deviation of 3.8 % and is a tool for future modeling purposes.

  20. Bed topography of Jakobshavn Isbræ, Greenland from high-resolution gravity data

    Science.gov (United States)

    An, L.; Rignot, E. J.; Morlighem, M.; Paden, J. D.; Holland, D. M.

    2015-12-01

    Jakobshavn Isbræ (JKS) is one of the largest marine terminating outlet glaciers in Greenland, feeding a fjord about 800 m deep in the west coast. JKS sped up more than twofold since 2002 and contributed nearly 1 mm of global sea level rise during the period from 2000 to 2011. Holland et al. (2008) posit that these changes coincided with a change in ocean conditions beneath the former ice tongue, yet little is known about the depth of the glacier at its grounding line and upstream of the grounding line and the sea floor depth of the fjord is not well known either. Here, we present a new approach to infer the glacier bed topography, ice thickness and sea floor bathymetry near the grounding line of JKS using high-resolution airborne gravity data from AirGRAV. AirGRAV data were collected in August 2012 from a helicopter platform. The data combined with radio echo sounding data, discrete point soundings in the fjord and the mass conservation approach on land ice. AirGRAV acquired a 500m spacing grid of free-air gravity data at 50 knots with sub-milligal accuracy, i.e. much higher than NASA Operation IceBridge (OIB)'s 5.2km resolution at 290 knots. We use a 3D inversion of the gravity data combining our observations and a forward modeling of the surrounding gravity field, and constrained at the boundary by radar echo soundings and point bathymetry. We reconstruct seamless bed topography at the grounding line that matches interior data and the sea floor bathymetry. The results reveal the true depth at the elbow of the terminal valley and the bed reversal in the proximity of the current grounding line. The analysis provides guidelines for future gravity survey of narrow fjords in terms of spatial resolution and gravity precision. The results also demonstrate the practicality of using high resolution gravity survey to resolve bed topography near glacier snouts, in places where radar sounding has been significantly challenged in the past. The inversion results are critical

  1. 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.

  2. Materials corrosion and protection at high temperatures

    International Nuclear Information System (INIS)

    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.)

  3. Thermoelastic properties of minerals at high temperature

    Indian Academy of Sciences (India)

    Sanjay Upadhyay; Hem Chandra; Meenakashi Joshi; Deepika P Joshi

    2011-01-01

    The knowledge of elasticity of the minerals is useful for interpreting the structure and composition of the lower mantle and also in seismic studies. The purpose of the present study is to discuss a simple and straightforward method for evaluating thermoelastic properties of minerals at high temperatures. We have extended the Kumar’s formulation by taking into the account the concept of anharmonicity in minerals above the Debye temperature (D). In our present study, we have investigated the thermophysical properties of two minerals (pyrope-rich garnet and MgAl2O4) under high temperatures and calculated the second-order elastic constant () and bulk modulus (T) of the above minerals, in two cases first by taking Anderson–Gruneisen parameter (T) as temperature-independent and then by treating T as temperature-dependent parameter. The results obtained when T is temperature-dependent are in close agreement with experimental data.

  4. S-RHT FIXED-BED HYDROTREATING TECHNOLOGY FOR RESIDUE WITH HIGH SULFUR CONTENT

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    To meet the demands of processing residue with high sulfur content, Fushun Research Institute of Petroleum and Petrochemicals (FRIPP) successfully developed the fixed-bed residue hydrotreating technology (S-RHT), which is suitable for treating high sulfur residue to produce diesel oil with low sulfur content. the hydrotreated 350 ℃+ residue is also a good feedstock for RFCC. Based on this technology, Maoming Petrochemical Company constructed the hydrotreating unit with a capacity of 2 Mt/a to treat high sulfur residue, in which loaded FZC series catalysts were developed by FRIPP. The unit was first put into commercial operation at the end of 1999. The commercial operation showed that the catalysts have good activities and the products meet the designed specifications.

  5. High-Resolution Adaptive Optics Test-Bed for Vision Science

    Energy Technology Data Exchange (ETDEWEB)

    Wilks, S C; Thomspon, C A; Olivier, S S; Bauman, B J; Barnes, T; Werner, J S

    2001-09-27

    We discuss the design and implementation of a low-cost, high-resolution adaptive optics test-bed for vision research. It is well known that high-order aberrations in the human eye reduce optical resolution and limit visual acuity. However, the effects of aberration-free eyesight on vision are only now beginning to be studied using adaptive optics to sense and correct the aberrations in the eye. We are developing a high-resolution adaptive optics system for this purpose using a Hamamatsu Parallel Aligned Nematic Liquid Crystal Spatial Light Modulator. Phase-wrapping is used to extend the effective stroke of the device, and the wavefront sensing and wavefront correction are done at different wavelengths. Issues associated with these techniques will be discussed.

  6. Low to high temperature energy conversion system

    Science.gov (United States)

    Miller, C. G. (Inventor)

    1977-01-01

    A method for converting heat energy from low temperature heat sources to higher temperature was developed. It consists of a decomposition chamber in which ammonia is decomposed into hydrogen and nitrogen by absorbing heat of decomposition from a low temperature energy source. A recombination reaction then takes place which increases the temperature of a fluid significantly. The system is of use for the efficient operation of compact or low capital investment turbine driven electrical generators, or in other applications, to enable chemical reactions that have a critical lower temperature to be used. The system also recovers heat energy from low temperature heat sources, such as solar collectors or geothermal sources, and converts it to high temperatures.

  7. Climate effect of an integrated wheat production and bioenergy system with Low Temperature Circulating Fluidized Bed gasifier

    DEFF Research Database (Denmark)

    Sigurjonsson, Hafthor Ægir; Elmegaard, Brian; Clausen, Lasse Røngaard;

    2015-01-01

    integration between the agricultural system and the energy system through the Low Temperature Circulating Fluidized Bed (LT-CFB) gasifier from the perspective of wheat grain production and electricity generation using wheat straw, where the effects of removing the straw from the agricultural system...... based on carbon conversion to two references, no straw removal and straw combustion. The results show that the climate effect of removing the straws are mitigated by the carbon soil sequestration with biochar, and electricity and district heat substitution. Maximum biochar production outperforms maximum...... heat and power generation for most substituted electricity and district heating scenarios. Irrespective of the substituted technologies, the carbon conversion needs to be 80-86% to fully mitigate the effects of removing the straws from the agricultural system. This concludes that compromising on energy...

  8. Reduction of Precursors of Chlorination By-products in Drinking Water Using Fluidized-bed Biofilm Reactor at Low Temperature

    Institute of Scientific and Technical Information of China (English)

    SHU-GUANG XIE; DONG-HUI WEN; DONG-WEN SHI; XIAO-YAN TANG

    2006-01-01

    Objective To investigate the reduction of chlorination by-products (CBPs) precursors using the fluidized-bed biofilm reactor (FBBR). Methods Reduction of total organic carbon (TOC), ultraviolet absorbance (UV254), trihalomethane (THM)formation potential (THMFP), haloacetic acid (HAA) formation potential (HAAFP), and ammonia in FBBR were evaluated in detail. Results The reduction of TOC or UV254 was low, on average 12.6% and 4.7%, respectively, while the reduction of THMFP and HAAFP was significant. The reduction of ammonia was 30%-40% even below 3℃, however, it could quickly rise to over 50% above 3℃. Conclusions The FBBR effectively reduces CBPs and ammonia in drinking water even at low temperature and seems to be a very promising and competitive drinking water reactor for polluted surface source waters, especially in China.

  9. Soil application of ash produced by low-temperature fluidized bed gasification: effects on soil nutrient dynamics and crop response

    DEFF Research Database (Denmark)

    Müller-Stöver, Dorette Sophie; Ahrenfeldt, Jesper; Holm, Jens Kai;

    2012-01-01

    Recycling of residual products of bioenergy conversion processes is important for adding value to the technologies and as a potential beneficial soil fertility amendment. In this study, two different ash materials originating from low temperature circulating fluidized bed (LT-CFB) gasification...... not significantly altered after ash application. SA was generally able to increase the levels of Olsen-P and of the ammonium acetate/acetic acid-extractable K in soil as well as to improve the yield of barley and maize, whereas faba bean did not react positively to ash amendment. CP did not show beneficial effects...... on soil nutrient levels or on crop biomass. We conclude from the results of this study, that—depending on the feedstock used—ashes from LT-CFB gasification of plant biomass can be used to replace mineral fertilizers if they are applied according to their nutrient content, the crop demand, and soil...

  10. Silicon Carbide Nanotube Oxidation at High Temperatures

    Science.gov (United States)

    Ahlborg, Nadia; Zhu, Dongming

    2012-01-01

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

  11. A high-temperature wideband pressure transducer

    Science.gov (United States)

    Zuckerwar, A. J.

    1975-01-01

    Progress in the development of a pressure transducer for measurement of the pressure fluctuations in the high temperature environment of a jet exhaust is reported. A condenser microphone carrier system was adapted to meet the specifications. A theoretical analysis is presented which describes the operation of the condenser microphone in terms of geometry, materials, and other physical properties. The analysis was used as the basis for design of a prototype high temperature microphone. The feasibility of connecting the microphone to a converter over a high temperature cable operating as a half-wavelength transmission line was also examined.

  12. Symposium on high temperature and materials chemistry

    International Nuclear Information System (INIS)

    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

  13. Basic studies on high-temperature engineering

    International Nuclear Information System (INIS)

    In response to increasing interest in high-temperature, gas-cooled reactors (HTGRs) and the need for improved knowledge of materials for nuclear applications that resist high temperatures, the NEA organised a first information exchange meeting on basic studies in the field of high-temperature engineering.The meeting was held in Paris on 27-29 september 1999 with 50 participants from 12 countries and four international organisations. Thirty two papers were submitted. The proceedings of the meeting cover studies on irradiation effects on advanced materials, safety-related behaviour of HTGRs and in-pile reactor instrumentation development. They also include recommendations for further promotion of international collaboration

  14. Symposium on high temperature and materials chemistry

    Energy Technology Data Exchange (ETDEWEB)

    1989-10-01

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

  15. High temperature ceramic/metal joint structure

    Science.gov (United States)

    Boyd, Gary L. (Inventor)

    1991-01-01

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

  16. Broadband, High-Temperature Ultrasonic Transducer

    Science.gov (United States)

    Parker, F. Raymond; Winfree, William P.; Barrows, Danny A.

    1995-01-01

    Materials chosen for endurance at high temperatures and acoustic coupling and damping. Acoustic transducer designed to exhibit broad frequency response and to survive temperatures close to melting points of brazing alloys. Attached directly and continuously to hot object monitored ultrasonically: for example, it can be attached to relatively cool spot on workpiece during brazing for taking ultrasonic quality-control measurements.

  17. Runaway Criterion in Fixed Bed Catalytic Reactors with Radial Temperature Profile

    Institute of Scientific and Technical Information of China (English)

    吴鹏; 樊勇; 李绍芬

    1999-01-01

    The discrepancy between pseudo-homogeneous one-dimensional model and peeudo-homogeneous two-dimensional model is studied. It is found that there are great differences between two models. This paper compares the maximum and minimum values of the radial temperature in the hot spot in came that a single exothermic reaction is carried out, a correlation is obtlioed with peeudo-homogeneous one-dimensional model to describe the entire reactor behavier. A new runaway criterion, based on the occurrence of inflection in the hot spot locus, is developed for the case of pseudo-homogeneous two-dimensional model. This criterion predicts the maximum allowable temperature for safe operation and the regions of runaway, respectively. The calculated results show that, compared with the results based on pseudo-homogeneous one-dimensional model, runaway will easily occur when the radial temperature gradient has to be considered.

  18. High Temperature Fiberoptic Thermal Imaging System Project

    Data.gov (United States)

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

  19. Specimen for high-temperature tensile tests

    Science.gov (United States)

    Coulbert, C. D.

    1972-01-01

    Split nut with internal taper to hold specially formed specimen composed of filaments of refractory material provides means for holding at high temperature and under tension so that performance evaluations may be made.

  20. High Temperature Capacitors for Venus Exploration Project

    Data.gov (United States)

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

  1. Silicon carbide, an emerging high temperature semiconductor

    Science.gov (United States)

    Matus, Lawrence G.; Powell, J. Anthony

    1991-01-01

    In recent years, the aerospace propulsion and space power communities have expressed a growing need for electronic devices that are capable of sustained high temperature operation. Applications for high temperature electronic devices include development instrumentation within engines, engine control, and condition monitoring systems, and power conditioning and control systems for space platforms and satellites. Other earth-based applications include deep-well drilling instrumentation, nuclear reactor instrumentation and control, and automotive sensors. To meet the needs of these applications, the High Temperature Electronics Program at the Lewis Research Center is developing silicon carbide (SiC) as a high temperature semiconductor material. Research is focussed on developing the crystal growth, characterization, and device fabrication technologies necessary to produce a family of silicon carbide electronic devices and integrated sensors. The progress made in developing silicon carbide is presented, and the challenges that lie ahead are discussed.

  2. Silicon carbide, an emerging high temperature semiconductor

    Science.gov (United States)

    Matus, Lawrence G.; Powell, J. Anthony

    In recent years, the aerospace propulsion and space power communities have expressed a growing need for electronic devices that are capable of sustained high temperature operation. Applications for high temperature electronic devices include development instrumentation within engines, engine control, and condition monitoring systems, and power conditioning and control systems for space platforms and satellites. Other earth-based applications include deep-well drilling instrumentation, nuclear reactor instrumentation and control, and automotive sensors. To meet the needs of these applications, the High Temperature Electronics Program at the Lewis Research Center is developing silicon carbide (SiC) as a high temperature semiconductor material. Research is focussed on developing the crystal growth, characterization, and device fabrication technologies necessary to produce a family of silicon carbide electronic devices and integrated sensors. The progress made in developing silicon carbide is presented, and the challenges that lie ahead are discussed.

  3. Growth kinetics of calcium fluoride at high supersaturation in a fluidized bed reactor.

    Science.gov (United States)

    Jiang, K; Zhou, K G; Yang, Y C; Du, H

    2014-01-01

    Crystallization process in a fluidized bed reactor (FBR) has been regarded as an environmentally friendly technology for the removal and recovery of fluoride from industrial wastewater. The growth kinetics of calcium fluoride at high supersaturation was studied for design, control, and operation of an FBR. The main variables, including supersaturation, superficial velocity, pH value, and particle size of seed that influenced the crystal growth were investigated. Then, a growth model was used to predict the linear growth rate of calcium fluoride at a high influent concentration of fluoride. The pressure difference in the FBR was used as a feature to characterize the growth rate of calcium fluoride. The aggregation and adsorption between seeds and fine particles were proven to be a possible mechanism for growth of calcium fluoride.

  4. Recent developments in high temperature organic polymers

    Science.gov (United States)

    Hergenrother, P. M.

    1991-01-01

    Developments in high temperature organic polymers during the last 5 years with major emphasis on polyimides and poly(arylene ether)s are discussed. Specific polymers or series of polymers have been selected to demonstrate unique properties or the effect chemical structure has upon certain properties. This article is not intended to be a comprehensive review of high temperature polymer advancements during the last 5 years.

  5. High-temperature reactor developments in the Netherlands

    Energy Technology Data Exchange (ETDEWEB)

    Schram, R.P.C.; Cordfunke, E.H.P.; Heek, A.I. van

    1996-01-01

    The high-temperature reactor development in the Netherland is embedded in the WHITE reactor program, in which several Dutch research institutes and engineering companies participate. The activities within the WHITE program are focused on the development of a small scale HTS for combined heat and power generation. In 1995, design choices for a pebble bed reactor were made at ECN. The first concept HTR will gave a closed cycle helium turbine and a power level of 40 MWth. It is intended to make the market introduction of a commercially competitive HTR feasible. The design will be an optimization of the Peu-a-Peu (PAP) concept of KFA Juelich. Computer codes necessary for the evaluation of reactor physics aspects of this reactor are developed in cooperation with international partners. An evaluation of a 20 MWth PAP concept showed that the maximum fuel termmperature after depressurization does not exceed 1300 C. (orig.).

  6. Study of hydrogen production at high temperature

    Energy Technology Data Exchange (ETDEWEB)

    Raoui, M.; Belhamel [Centre de Developpement des Energies Renouvelables, BP 62 route de l observatoire Village celleste, Bouzareah Alger, (Algeria); Miri [Universite des sciences et de la technologie houari boumediene, Alger, (Algeria); Benyoucef [Universite de Tlemcen, Tlemcen, (Algeria)

    2006-07-01

    In this study, we evaluate the hydrogen production per electrolysis at high temperature. The increase in the pressure and the temperature of water are done by a solar power station, the electrolysis of water is done at high temperature 900 C 30 bars. We carry out the design of a generating station of hydrogen treating a flow rate of 1 kg/s of water vapour, then we simulate the production of this installation in various towns of Algeria. The results show the great potential energy of the cities of the Algerian south. (authors)

  7. Relativistic QED Plasma at Extremely High Temperature

    CERN Document Server

    Masood, Samina S

    2016-01-01

    Renormalization scheme of QED (Quantum Electrodynamics) at high temperatures is used to calculate the effective parameters of relativistic plasma in the early universe. Renormalization constants of QED play role of effective parameters of the theory and can be used to determine the collective behavior of the medium. We explicitly show that the dielectric constant, magnetic reluctivity, Debye length and the plasma frequency depend on temperature in the early universe. Propagation speed, refractive index, plasma frequency and Debye shielding length of a QED plasma are computed at extremely high temperatures in the early universe. We also found the favorable conditions for the relativistic plasma from this calculations.

  8. Electrons and Phonons in High Temperature Superconductors

    Directory of Open Access Journals (Sweden)

    Anu Singh

    2013-01-01

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

  9. High Temperature Endurable Fiber Optic Accelerometer

    Directory of Open Access Journals (Sweden)

    Yeon-Gwan Lee

    2014-01-01

    Full Text Available This paper presents a low frequency fiber optic accelerometer for application in high temperature environments of civil engineering structures. The reflection-based extrinsic fiber optic accelerometer developed in this study consists of a transmissive grating panel, reflective mirror, and two optical fiber collimators as the transceiver whose function can be maintained up to 130°C. The dynamic characteristics of the sensor probe were investigated and the correlation between the natural frequency of the sensor probe and temperature variation was described and discussed. Furthermore, high temperature simulation equipment was designed for the verification test setup of the developed accelerometer for high temperature. This study was limited to consideration of 130°C applied temperature to the proposed fiber optic accelerometer due to an operational temperature limitation of commercial optical fiber collimator. The sinusoidal low frequency accelerations measured from the developed fiber optic accelerometer at 130°C demonstrated good agreement with that of an MEMS accelerometer measured at room temperature. The developed fiber optic accelerometer can be used in frequency ranges below 5.1 Hz up to 130°C with a margin of error that is less than 10% and a high sensitivity of 0.18 (m/s2/rad.

  10. 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

  11. 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.

  12. High-temperature granulites and supercontinents

    Institute of Scientific and Technical Information of China (English)

    J.L.R. Touret; M. Santosh; J.M. Huizenga

    2016-01-01

    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 post-dating 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.

  13. 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.

  14. High-entropy alloys as high-temperature thermoelectric materials

    Science.gov (United States)

    Shafeie, Samrand; Guo, Sheng; Hu, Qiang; Fahlquist, Henrik; Erhart, Paul; Palmqvist, Anders

    2015-11-01

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

  15. Fast vortex core switching at high temperatures

    Science.gov (United States)

    Lebecki, Kristof M.; Legut, Dominik

    2016-08-01

    Fast ferromagnetic vortex core switching is investigated employing micromagnetic simulations. Short pulse (in the range of a few hundreds of picoseconds) of an in-plane oscillating magnetic field is applied to a thin disk (diameter 200 nm and thickness 20 nm) with material parameters resembling permalloy. Fundamental frequency of this excitation field is close to the resonance with the material spin waves. Thermal effects are introduced by replacing the Landau-Lifshitz-Gilbert equation by the Landau-Lifshitz-Bloch equation. Temperature from 300 K to 850 K is considered, just below the Curie temperature TC = 870 K. Calculations are done within the OOMMF simulation framework. We find that: (i) Period of the field necessary to switch the vortex increases approximately from 141 ps at 300 K to 572 ps for the high-temperature limit. (ii) Amplitude of the field necessary to switch the vortex core decreases roughly from 60 mT to 15 mT - even at high temperatures this amplitude is nonzero, contrary to the case of quasi-static switching. (iii) Time span between the excitation and switching (switching time) seems not to depend on the temperature. (iv) Duration of the switching itself (movement of the Bloch point in the sample) increases from a few picoseconds at low temperatures to tens of picoseconds at high temperatures.

  16. High-temperature testing of high performance fiber reinforced concrete

    Science.gov (United States)

    Fořt, Jan; Vejmelková, Eva; Pavlíková, Milena; Trník, Anton; Čítek, David; Kolísko, Jiří; Černý, Robert; Pavlík, Zbyšek

    2016-06-01

    The effect of high-temperature exposure on properties of High Performance Fiber Reinforced Concrete (HPFRC) is researched in the paper. At first, reference measurements are done on HPFRC samples without high-temperature loading. Then, the HPFRC samples are exposed to the temperatures of 200, 400, 600, 800, and 1000 °C. For the temperature loaded samples, measurement of residual mechanical and basic physical properties is done. Linear thermal expansion coefficient as function of temperature is accessed on the basis of measured thermal strain data. Additionally, simultaneous difference scanning calorimetry (DSC) and thermogravimetry (TG) analysis is performed in order to observe and explain material changes at elevated temperature. It is found that the applied high temperature loading significantly increases material porosity due to the physical, chemical and combined damage of material inner structure, and negatively affects also the mechanical strength. Linear thermal expansion coefficient exhibits significant dependence on temperature and changes of material structure. The obtained data will find use as input material parameters for modelling the damage of HPFRC structures exposed to the fire and high temperature action.

  17. High-temperature superconducting conductors and cables

    International Nuclear Information System (INIS)

    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 Jc 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 Jc 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

  18. Structure and composition of biofilm communities in a moving bed biofilm reactor for nitritation-anammox at low temperatures.

    Science.gov (United States)

    Persson, Frank; Sultana, Razia; Suarez, Marco; Hermansson, Malte; Plaza, Elzbieta; Wilén, Britt-Marie

    2014-02-01

    It is a challenge to apply anaerobic ammonium oxidation (anammox) for nitrogen removal from wastewater at low temperatures. Maintenance of anammox- and aerobic ammonia oxidizing bacteria (AOB) and suppression of nitrite oxidizing bacteria (NOB) are key issues. In this work, a nitritation-anammox moving bed biofilm pilot reactor was operated at 19-10°C for 300 d. Nitrogen removal was decreasing, but stable, at 19-13°C. At 10°C removal became unstable. Quantitative PCR, fluorescence in situ hybridization and gene sequencing showed that no major microbial community changes were observed with decreased temperature. Anammox bacteria dominated the biofilm (0.9-1.2 × 10(14) 16S rRNA copies m(-2)). Most anammox bacteria were similar to Brocadia sp. 40, but another smaller Brocadia population was present near the biofilm-water interface, where also the AOB community (Nitrosomonas) was concentrated in thin layers (1.8-5.3 × 10(12) amoA copies m(-2)). NOB (Nitrobacter, Nitrospira) were always present at low concentrations (<1.3 × 10(11) 16S rRNA copies m(-2)).

  19. Thermal treatment of high-caloric waste in fluidized bed incineration plants in Austria

    International Nuclear Information System (INIS)

    The importance of thermal treatment of waste and residues in Austria is expected to rise due to the current changes of the legal situation in waste management. Assessing the rank order of different thermal treatment processes for waste management it has been shown that - especially caused by the rising importance of the mechanical treatment step in the mechanical-biological residual waste treatment and the subsequent necessity of the thermal treatment of a high-caloric preprocessed waste stream - the importance of the fluidized bed technology will increase. The main advantages are the high existing capacities as well as the flexibility of this technology in regard of fuel properties and further on the fact of the lacking influence of the ash towards the quality of a product. This is true although the thermal treatment in fluidized bed incinerators requires some processing of the waste. This doctoral thesis also contains a thorough physical and chemical characterization of various waste fuels - especially those which have been used during full scale incineration experiments. This characterization includes a comparison with fossil fuel. The practical part contains the documentation and balancing of full scale incineration experiments. A comparison of a reference experiment with experiments when waste fuel has been thermally utilized showed that a significant increase of emissions to the atmosphere has not been observed. Based on the incineration experiments conclusions in regard of waste fuels as well as different categories of thermal treatment plants are being stated. Finally, a recommendation of the assignation of various waste streams to different categories of thermal treatment plants is being made. (author)

  20. Development of high temperature ultrasonic transducers

    International Nuclear Information System (INIS)

    Structural health monitoring (SHM) techniques are needed to maintain the reliability of power plants for long term operation. The high temperature transducers are necessary to realize SHM (monitor wall thickness of the pipings, crack growth in the materials and material evaluation) under the working condition of power plants. We have evaluated lithium niobate (LiNbO3) single crystal which is well known as a high Curie temperature piezoelectric material to develop high temperature ultrasonic transducers. The LiNbO3 was bonded onto a stainless steel substrate. The experimental transducer was heated in an electric furnace while measuring the bottom echoes from the substrate. We confirmed that the experimental high temperature transducer could work up to 1000degC. Thermal and chemical stability of LiNbO3 were confirmed using TG measurement up to 1260degC (melting point). Additionally, we have developed single and array transducers for high temperature ultrasonic measurement based on those experimental data. (author)

  1. High temperature estimation through computer vision

    International Nuclear Information System (INIS)

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

  2. Effects of High Temperature on Collector Coatings

    Science.gov (United States)

    Lowery, J. R.

    1982-01-01

    Report reveals electroplated black chrome is good coating for concentrating collectors in which temperatures are in the 650 degrees-800 degrees F (340 degrees - 430 degrees C) range. Black chrome thermal emittance is low and solar-absorption properties are not seriously degraded at high temperatures. Black coatings are used to increase absorption of solar energy by base metal while decreasing emission of infrared energy. Coatings are intended to improve efficiency of solar collectors.

  3. High-Temperature Liquid Metal Infusion Considering Surface Tension-Viscosity Dissipation

    Science.gov (United States)

    Kumar, Vinod; Harris, Christopher K.; Bronson, Arturo; Shantha-Kumar, Sanjay; Medina, Arturo

    2016-02-01

    In considering the significant effect of the surface tension-viscosity dissipation driving the fluid flow within a capillary, high-temperature liquid metal infusion was analyzed for titanium, yttrium, hafnium, and zirconium penetrating into a packed bed. A model of the dissipation considers the momentum balance within the capillary to determine the rate of infusion, which is compared with the Semlak-Rhines model developed for liquid metal penetration into a packed bed assumed as a bundle of tubes mimicking the porosity of a packed bed. For liquid Ti, the penetration rate was calculated from 0.2 µs to 1 ms and rose to a maximum of 7 m/s at approximately 1 µs; after which, the rate decreased to 0.7 m/s at 1 ms. Beyond 10 µs, the decreasing trend of the rate of penetration determined by the model of dissipation compared favorably with the Semlak-Rhines equation.

  4. Fluidized-bed calciner with combustion nozzle and shroud

    Science.gov (United States)

    Wielang, Joseph A.; Palmer, William B.; Kerr, William B.

    1977-01-01

    A nozzle employed as a burner within a fluidized bed is coaxially enclosed within a tubular shroud that extends beyond the nozzle length into the fluidized bed. The open-ended shroud portion beyond the nozzle end provides an antechamber for mixture and combustion of atomized fuel with an oxygen-containing gas. The arrangement provides improved combustion efficiency and excludes bed particles from the high-velocity, high-temperature portions of the flame to reduce particle attrition.

  5. Bed Agglomeration During the Steam Gasification of a High Lignin Corn Stover Simultaneous Saccharification and Fermentation (SSF) Digester Residue

    Energy Technology Data Exchange (ETDEWEB)

    Howe, Daniel T.; Taasevigen, Danny J.; Gerber, Mark A.; Gray, Michel J.; Fernandez, Carlos A.; Saraf, Laxmikant; Garcia-Perez, Manuel; Wolcott, Michael P.

    2015-11-13

    This research investigates the bed agglomeration phenomena during the steam gasification of a high lignin residue produced from the simultaneous saccharification and fermentation (SSF) of corn stover in a bubbling fluidized bed. The studies were conducted at 895°C using alumina as bed material. Biomass was fed at 1.5 kg/hr, while steam was fed to give a velocity equal to 2.5 times the minimum fluidization velocity, with a steam/carbon ratio of 0.9. The pelletized feedstock was co-fed with a cooling nitrogen stream to mitigate feed line plugging issues. Tar production was high at 50.3 g/Nm3, and the fraction of C10+ compounds was greater than that seen in the gasification of traditional lignocellulosic feedstocks. Carbon closures over 94 % were achieved for all experiments. Bed agglomeration was found to be problematic, indicated by pressure drop increases observed below the bed and upstream of the feed line. Two size categories of solids were recovered from the reactor, +60 mesh and -60 mesh. After a 2.75-hour experiment, 61.7 wt % was recovered as -60 mesh particles and 38.2 wt% of the recovered reactor solids were +60 mesh. A sizeable percentage, 31.8 wt%, was +20 mesh. The -60 mesh particles were mainly formed by the initial bed material (Al2O3). Almost 50 wt. % of the + 20 mesh particles was found to be formed by organics. The unreacted carbon remaining in the reactor resulted in a low conversion rate to product gas. ICP-AES, SEM, SEM-EDS, and XRD confirmed that the large agglomerates (+ 20 mesh) were not encapsulated bed material but rather un-gasified feedstock pellets with sand particles attached to it.

  6. Equivalent materials simulation experimental study on bed separations developing and mining subsidence in constant humidity and constant temperature conditions

    Institute of Scientific and Technical Information of China (English)

    FU Zhi-liang; WANG Su-hua; GAO Yan-fa

    2008-01-01

    A new experiment was made on the developing of bed separations and mining subsidence from Tangshan T2192 working face by equivalent materials simulation.The overburden deformation and the developing of bed separations with working face advancing was simulated by a new model.The results show that the maximum value of bed separations moved forward gradually along with the working face advancing; the maximum value of bed separations is 0.31~0.50 times of mining thickness.The key strata have a great influence upon surface subsidence during the overburden movement process.The mechanics parameters of new experiment are fitted with results in fields perfectly.

  7. Joining of ultra-high temperature ceramics

    OpenAIRE

    Silvestroni, Laura; Sciti, Diletta; Esposito, Laura; Glaeser, Andreas

    2012-01-01

    In the last decade, ultra-high temperature ceramics raised renewed interest after the first studies in the 60's. Thanks to their high melting point, superior to any group of materials, and to their set of interesting physical and engineering properties, they find application in aerospace industry, propulsion field, as cladding materials in generation IV nuclear reactors and solar absorbers in novel HT CSP systems. Recent efforts were devoted to the achievement of high strength and toughness m...

  8. High temperature and pressure alkaline electrolysis

    DEFF Research Database (Denmark)

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

    2013-01-01

    Alkaline electrolyzers have proven to operate reliable for decades on a large scale, but in order to become commercially attractive and compete against conventional technologies for hydrogen production, the production and investment costs have to be reduced. This may occur by increasing the...... operational temperature and pressure to produce pressurized hydrogen at high rate (m3 H2·h-1·m-2 cell area) and high electrical efficiency. This work describes an exploratory technical study of the possibility to produce hydrogen and oxygen with a new type of alkaline electrolysis cell at high temperatures...... SrTiO3 was used for immobilization of aqueous KOH solutions. Electrolysis cells with this electrolyte and metal foam based gas diffusion electrodes were successfully demonstrated at temperatures up to 250 °C at 40 bar. Different electro-catalysts were tested in order to reduce the oxygen and hydrogen...

  9. High temperature thermoelectric properties of boron carbide

    International Nuclear Information System (INIS)

    Boron carbides are refractory solids with potential for application as very high temperature p-type thermoelectrics in power conversion applications. The thermoelectric properties of boron carbides are unconventional. In particular, the electrical conductivity is consistent with the thermally activated hopping of a high density (∼1021/cm3) of bipolarons; the Seebeck coefficient is anomalously large and increases with increasing temperature; and the thermal conductivity is surprisingly low. In this paper, these unusual properties and their relationship to the unusual structure and bonding present in boron carbides are reviewed. Finally, the potential for utilization of boron carbides at very high temperatures (up to 2200 degrees C) and for preparing n-type materials is discussed

  10. High throughput production of double emulsions using packed bed premix emulsification

    NARCIS (Netherlands)

    Sahin, S.; Sawalha, H.I.M.; Schroen, C.G.P.H.

    2014-01-01

    We explored the potential of packed bed premix emulsification for homogenizing coarse food grade W/O/W emulsions, prepared with sunflower oil. Using packed beds with different glass bead sizes (30–90 µm) at different applied pressures (200–600 kPa), emulsions with reasonably uniform droplet size (sp

  11. Thermal Hydraulics of the Very High Temperature Gas Cooled Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Chang Oh; Eung Kim; Richard Schultz; Mike Patterson; Davie Petti

    2009-10-01

    The U.S Department of Energy (DOE) is conducting research on the Very High Temperature Reactor (VHTR) design concept for the Next Generation Nuclear Plant (NGNP) Project. The reactor design will be a graphite moderated, thermal neutron spectrum reactor that will produce electricity and hydrogen in a highly efficient manner. The NGNP reactor core will be either a prismatic graphite block type core or a pebble bed core. The NGNP will use very high-burnup, low-enriched uranium, TRISO-coated fuel, and have a projected plant design service life of 60 years. The VHTR concept is considered to be the nearest-term reactor design that has the capability to efficiently produce hydrogen. The plant size, reactor thermal power, and core configuration will ensure passive decay heat removal without fuel damage or radioactive material releases during reactor core-accidents. The objectives of the NGNP Project are to: Demonstrate a full-scale prototype VHTR that is commercially licensed by the U.S. Nuclear Regulatory Commission, and Demonstrate safe and economical nuclear-assisted production of hydrogen and electricity. The DOE laboratories, led by the INL, perform research and development (R&D) that will be critical to the success of the NGNP, primarily in the areas of: • High temperature gas reactor fuels behavior • High temperature materials qualification • Design methods development and validation • Hydrogen production technologies • Energy conversion. This paper presents current R&D work that addresses fundamental thermal hydraulics issues that are relevant to a variety of possible NGNP designs.

  12. Thermal Hydraulics of the Very High Temperature Gas Cooled Reactor

    International Nuclear Information System (INIS)

    The U.S Department of Energy (DOE) is conducting research on the Very High Temperature Reactor (VHTR) design concept for the Next Generation Nuclear Plant (NGNP) Project. The reactor design will be a graphite moderated, thermal neutron spectrum reactor that will produce electricity and hydrogen in a highly efficient manner. The NGNP reactor core will be either a prismatic graphite block type core or a pebble bed core. The NGNP will use very high-burnup, low-enriched uranium, TRISO-coated fuel, and have a projected plant design service life of 60 years. The VHTR concept is considered to be the nearest-term reactor design that has the capability to efficiently produce hydrogen. The plant size, reactor thermal power, and core configuration will ensure passive decay heat removal without fuel damage or radioactive material releases during reactor core-accidents. The objectives of the NGNP Project are to: Demonstrate a full-scale prototype VHTR that is commercially licensed by the U.S. Nuclear Regulatory Commission, and Demonstrate safe and economical nuclear-assisted production of hydrogen and electricity. The DOE laboratories, led by the INL, perform research and development (R and D) that will be critical to the success of the NGNP, primarily in the areas of: (1) High temperature gas reactor fuels behavior; (2) High temperature materials qualification; (3) Design methods development and validation; (4) Hydrogen production technologies; and (5) Energy conversion. This paper presents current R and D work that addresses fundamental thermal hydraulics issues that are relevant to a variety of possible NGNP designs

  13. Thermal hydraulics of the very high temperature gas cooled reactor

    International Nuclear Information System (INIS)

    The Idaho National Laboratory (INL), under the auspices of the U.S. Department of Energy, is conducting research on the Very High Temperature Reactor (VHTR) design concept for the Next Generation Nuclear Plant (NGNP) Project. The reactor design will be a graphite moderated, thermal neutron spectrum reactor that will produce electricity and hydrogen in a highly efficient manner. The NGNP reactor core will be either a prismatic graphite block type core or a pebble bed core. The NGNP will use very high-burnup, low-enriched uranium, TRISO-coated fuel, and have a projected plant design service life of 60 years. The VHTR concept is considered to be the nearest-term reactor design that has the capability to efficiently produce hydrogen. The plant size, reactor thermal power, and core configuration will ensure passive decay heat removal without fuel damage or radioactive material releases during reactor core-accidents. The objectives of the NGNP Project are to: Demonstrate a full-scale prototype VHTR that is commercially licensed by the U.S. Nuclear Regulatory Commission, and Demonstrate safe and economical nuclear-assisted production of hydrogen and electricity. The DOE laboratories, led by the INL, perform research and development (R and D) that will be critical to the success of the NGNP, primarily in the areas of: · High temperature gas reactor fuels behavior · High temperature materials qualification · Design methods development and validation · Hydrogen production technologies · Energy conversion. This paper presents current R and D work that addresses fundamental thermal hydraulics issues that are relevant to a variety of possible NGNP designs. (author)

  14. 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...

  15. Materials for high-temperature fuel cells

    CERN Document Server

    Jiang, San Ping; Lu, Max

    2013-01-01

    There are a large number of books available on fuel cells; however, the majority are on specific types of fuel cells such as solid oxide fuel cells, proton exchange membrane fuel cells, or on specific technical aspects of fuel cells, e.g., the system or stack engineering. Thus, there is a need for a book focused on materials requirements in fuel cells. Key Materials in High-Temperature Fuel Cells is a concise source of the most important and key materials and catalysts in high-temperature fuel cells with emphasis on the most important solid oxide fuel cells. A related book will cover key mater

  16. Additive Manufacturing of Advanced High Temperature Masking Fixtures for EBPVD TBC Coating

    Energy Technology Data Exchange (ETDEWEB)

    List, III, Frederick Alyious [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Feuerstein, Albert [Praxair Surface Technologies, Inc., (United States); Dehoff, Ryan [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Kirka, Michael [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Carver, Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2016-03-30

    The purpose of this Manufacturing Demonstration Facility (MDF) technical collaboration project between Praxair Surface Technologies, Inc. (PST) and Oak Ridge National Laboratory (ORNL) was to develop an additive manufacturing process to fabricate next generation high temperature masking fixtures for coating of turbine airfoils with ceramic Thermal Barrier Coatings (TBC) by the Electron Beam Physical Vapor Deposition (EBPVD) process. Typical masking fixtures are sophisticated designs and require complex part manipulation in order to achieve the desired coating distribution. Fixtures are typically fabricated from high temperature nickel (Ni) based superalloys. The fixtures are fabricated from conventional processes by welding of thin sheet material into a complex geometry, to decrease the weight load for the manipulator and to reduce the thermal mass of the fixture. Recent attempts have been made in order to fabricate the fixtures through casting, but thin walled sections are difficult to cast and have high scrap rates. This project focused on understanding the potential for fabricating high temperature Ni based superalloy fixtures through additive manufacturing. Two different deposition processes; electron beam melting (EBM) and laser powder bed fusion were evaluated to determine the ideal processing route of these materials. Two different high temperature materials were evaluated. The high temperature materials evaluated were Inconel 718 and another Ni base alloy, designated throughout the remainder of this document as Alloy X, as the alloy composition is sensitive. Inconel 718 is a more widely utilized material for additive manufacturing although it is not currently the material utilized for current fixtures. Alloy X is the alloy currently used for the fixtures, but is not a commercially available alloy for additive manufacturing. Praxair determined it was possible to build the fixture using laser powder bed technology from Inconel 718. ORNL fabricated the fixture

  17. High-temperature MAS-NMR at high spinning speeds.

    Science.gov (United States)

    Kirchhain, Holger; Holzinger, Julian; Mainka, Adrian; Spörhase, Andreas; Venkatachalam, Sabarinathan; Wixforth, Achim; van Wüllen, Leo

    2016-09-01

    A low cost version to enable high temperature MAS NMR experiments at temperatures of up to 700°C and spinning speeds of up to 10kHz is presented. The method relies on inductive heating using a metal coated rotor insert. The metal coating is accomplished via a two step process involving physical vapor deposition and galvanization.

  18. Fiber Bragg Grating Filter High Temperature Sensors

    Science.gov (United States)

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

    2001-01-01

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

  19. Bed load size distribution and flow conditions in a high mountain catchment of Central Pyrenees

    Directory of Open Access Journals (Sweden)

    Martínez-Castroviejo, Ricardo

    1990-06-01

    Full Text Available The bed load size distribution caused by different types of flow are compared in a high mountain catchment located in the upper Gallego river basin (Central Spanish’ Pyrenees. Three kinds of hydrologic events could be defined: those triggered by heavy autumn rainfalls, those originated by isolated summer rainstorms and those promoted by snowmelting. Each one is characterized by a peculiar bed load size distribution. Thus, it could be demonstrated that the coarser fractions, above 30 mm in diameter, are up to six times more abundant, in percentage of total weight, in transports caused by heavy rainfalls than in the material collected after snowmelt flows. In its turn, bed load mobilized by snowmelt flows is mainly composed by medium and fine gravel, from 2 to 8 mm. These may amount up to 60 % of total weight of bed load. The reasons for these so different size distributions are discussed.

    [es] En una cuenca de alta montaña localizada en el alto valle del río Gallego (Pirineo central se comparan las distribuciones por tamaños de los acarreos movilizados por diferentes tipos de caudal. Tres tipos de eventos hidrológicos han podido ser caracterizados: los ocasionados por intensas lluvias de otoño, los originados por tormentas estivales aisladas y los producidos por la fusión de la nieve acumulada durante el invierno. Se concluye que cada uno de ellos lleva asociada una distribución por tamaños típica de la carga de fondo. Así, se ha comprobado que las fracciones más gruesas consideradas -superiores a los 30 mm de diámetro- son hasta seis veces más abundantes -en porcentaje sobre el peso total- en las exportaciones causadas por lluvias de gran intensidad que en las generadas por caudales de fusión. A su vez, las descargas ocasionadas por la fusión arrastran principalmente gravas de calibre medio y fino -entre 2y8 mm- que llegan a suponer el 60 % en peso del volumen movilizado. Este artículo discute las razones que provocan

  20. High-temperature borate crystal chemistry

    Energy Technology Data Exchange (ETDEWEB)

    Bubnova, Rimma S. [Russian Academy of Sciences, St. Petersburg (Russian Federation). Grebenshchikov Institute of Silicate Chemistry; Saint Petersburg State Univ. (Russian Federation). Dept. of Crystallography; Filatov, Stanislav K. [Saint Petersburg State Univ. (Russian Federation). Dept. of Crystallography

    2013-10-01

    The paper presents a brief review of the present state of high-temperature borate crystal chemistry. This review summarizes the results of high- and low-temperature single crystal X-ray diffraction studies for more than 10 borate structures and high-temperature powder Xray diffraction data for about 65 borates. Thermal behavior of their crystal structures, thermal expansion, polymorphic transitions and their relationship to borate glasses are presented. These studies allow to formulate the basic principles of high-temperature borate crystal chemistry and to reveal the regularities of thermal behavior of borates. On heating, the BO{sub 3} and BO{sub 4} polyhedra and rigid groups consisting of these polyhedra, practically maintain their configuration and size, but they are able to rotate like hinges exhibiting highly anisotropic thermal expansion, including linear negative expansion. Based on these results, we generalize the term 'rigid group' and render thermal vibrations as the key ingredient for the self-assembly of borate rigid groups. (orig.)

  1. High-Temperature Capacitor Polymer Films

    Science.gov (United States)

    Tan, Daniel; Zhang, Lili; Chen, Qin; Irwin, Patricia

    2014-12-01

    Film capacitor technology has been under development for over half a century to meet various applications such as direct-current link capacitors for transportation, converters/inverters for power electronics, controls for deep well drilling of oil and gas, direct energy weapons for military use, and high-frequency coupling circuitry. The biaxially oriented polypropylene film capacitor remains the state-of-the-art technology; however, it is not able to meet increasing demand for high-temperature (>125°C) applications. A number of dielectric materials capable of operating at high temperatures (>140°C) have attracted investigation, and their modifications are being pursued to achieve higher volumetric efficiency as well. This paper highlights the status of polymer dielectric film development and its feasibility for capacitor applications. High-temperature polymers such as polyetherimide (PEI), polyimide, and polyetheretherketone were the focus of our studies. PEI film was found to be the preferred choice for high-temperature film capacitor development due to its thermal stability, dielectric properties, and scalability.

  2. High temperature reactors for cogeneration applications

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-05-15

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

  3. 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

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

    Data.gov (United States)

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

  5. High temperature fatigue behaviour of intermetallics

    Indian Academy of Sciences (India)

    K Bhanu Sankara Rao

    2003-06-01

    There would be considerable benefits in developing new structural materials where high use temperatures and strength coupled with low density are minimum capabilities. Nickel and titanium aluminides exhibit considerable potential for near-term application in various branches of modern industry due to the number of property advantages they possess including low density, high melting temperature, high thermal conductivity, and excellent environmental resistance, and their amenability for significant improvment in creep and fatigue resistance through alloying. Reliability of intermetallics when used as engineering materials has not yet been fully established. Ductility and fracture toughness at room and intermediate temperatures continue to be lower than the desired values for production implementation. In this paper, progress made towards improving strain-controlled fatigue resistance of nickel and titanium aluminides is outlined. The effects of manufacturing processes and micro alloying on low cycle fatigue behaviour of NiAl are addressed. The effects of microstructure, temperature of testing, section thickness, brittle to ductile transition temperature, mean stress and environment on fatigue behaviour of same -TiAl alloys are discussed.

  6. Bimodular high temperature planar oxygen gas sensor

    Directory of Open Access Journals (Sweden)

    Xiangcheng eSun

    2014-08-01

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

  7. High Summer Temperatures and Mortality in Estonia.

    Directory of Open Access Journals (Sweden)

    Daniel Oudin Åström

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

  8. Gravimeter using high-temperature superconductor bearing.

    Energy Technology Data Exchange (ETDEWEB)

    Hull, J. R.

    1998-09-11

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

  9. Characteristics of high power LEDs at high and low temperature*

    Institute of Scientific and Technical Information of China (English)

    Guo Weling; Jia Xuejiao; Yin Fei; Cui Bifeng; Gao Wei; Liu Ying; Yan Weiwei

    2011-01-01

    The high power light emitting diodes (LEDs) based on InGaN and AlGaInP individually are tested on line at temperatures from -30 to 100 ℃. The data are fitted to measure the relationship between temperature and the properties of forward voltage, relative light intensity, wavelength, and spectral bandwidth of two different kinds of LEDs. Why these properties changed and how these changes reflected on applicatons are also analyzed and compared with each other. The results show that temperature has a great influence on the performance and application of power LEDs. For applications at low temperature, the forward voltage rising and the peak wavelength blue-shifting must be considered; and at high temperature, the relative light intensity decreasing and the peak wavelength red-shifting must be considered

  10. 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.

  11. High Temperature Corrosion in Biomass Incineration Plants

    DEFF Research Database (Denmark)

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

    1997-01-01

    The aim of the project is to study the role of ash deposits in high temperature corrosion of superheater materials in biomass and refuse fire combined heat and power plants. The project has included the two main activities: a) A chemical characterisation of ash deposits collected from a major...

  12. Nuclear and Quark Matter at High Temperature

    CERN Document Server

    Biro, T S; Schram, Z

    2016-01-01

    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.

  13. Enamel for high-temperature superalloys

    Science.gov (United States)

    Levin, H.; Lent, W. E.

    1977-01-01

    Desired optical and high temperature enamel properties are obtained with glasses prepared from the system Li2O-ZrO2-nSiO2. Molar compositions range from n=4 to n=1.3, to which are added minor amounts in varying combinations of alumina, alkali fluorides, boric oxide, alkali oxides, and akaline earth oxides.

  14. Solar-driven high temperature radiant cooling

    Institute of Scientific and Technical Information of China (English)

    SONG ZhaoPei; WANG RuZhu; ZHAI XiaoQiang

    2009-01-01

    Solar energy is widely used as one of the most important renewable energy. In addition to the growing applications of solar PV and solar water heater, solar cooling is also considered very valuable and the related researches are developing fast because of the synchronism between solar irradiance and building cooling load. Current studies mainly focus on the high temperature solar collector technique and heat-driven cooling technique, while little concern has been paid to the transport process of cooling power. In this paper, the high temperature radiant cooling is studied as an alternative way for transporting cooling power, and the performance of the combination of radiant ceiling and solar cooling is also studied. From simulation and theoretical analysis results, high temperature radiant cooling terminal shows better cooling power transportation ability against conventional air-conditioning terminal, and its thermal comfort is improved. Experiment results indicate that radiant cooling can enhance the chiller's COP (Coefficient of Performance) by 17% and cooling power regeneration by 50%.According to analysis in this paper, high temperature radiant cooling is proved to be suitable for solar cooling system, and out work can serve as a reference for later system design and promotion.

  15. High temperature pressure coupled ultrasonic waveguide

    International Nuclear Information System (INIS)

    A pressure coupled ultrasonic waveguide is provided to which one end may be attached a transducer and at the other end a high temperature material for continuous ultrasonic testing of the material. The ultrasonic signal is coupled from the waveguide into the material through a thin, dry copper foil

  16. High temperature applications of nuclear energy

    International Nuclear Information System (INIS)

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

  17. High temperature polymer electrolyte membrane fuel cells

    DEFF Research Database (Denmark)

    This book is a comprehensive review of high-temperature polymer electrolyte membrane fuel cells (PEMFCs). PEMFCs are the preferred fuel cells for a variety of applications such as automobiles, cogeneration of heat and power units, emergency power and portable electronics. The first 5 chapters...

  18. High-temperature carbidization of carboniferous rocks

    Science.gov (United States)

    Goldin, B. A.; Grass, V. E.; Nadutkin, A. V.; Nazarova, L. Yu.

    2009-08-01

    Processes of thermal metamorphism of carboniferous rocks have been studied experimentally. The conditions of high-temperature interaction of shungite carbon with components of the contained rocks, leading to formation of carbide compounds, have been determined. The results of this investigation contribute to the works on searching for new raw material for prospective material production.

  19. Recent developments in high temperature superconductivity. Proceedings

    International Nuclear Information System (INIS)

    The following topics were dealt with: high-temperature superconductivity: synthesis, structural features, doping and pressure effects, electronic transitions, recent magnetic studies, electron-doped superconductors, spin fluctuations and d wave pairing, properties of layers and multilayers, transport properties, vortices in superconductors, coexistence of magnetism and superconductivity. All 22 papers are separately analyzed for the database

  20. Metallic Membranes for High Temperature Hydrogen Separation

    DEFF Research Database (Denmark)

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

    2013-01-01

    Composite palladium membranes have extensively been studied in laboratories and, more recently, in small pilot industrial applications for the high temperature separation of hydrogen from reactant mixtures such as water-gas shift (WGS) reaction or methane steam reforming (MSR). Composite Pd...

  1. The Evolution of High Temperature Gas Sensors.

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-01-01

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

  2. Effective Thermal Conductivity of Adsorbent Packed Beds

    Science.gov (United States)

    Mori, Hideo; Hamamoto, Yoshinori; Yoshida, Suguru

    The effective thermal conductivity of adsorbent packed beds of granular zeolite 13X and granular silica gel A in the presence of stagnant steam or air was measured under different conditions of the adsorbent bed temperature, particle size and filler-gas pressure. The measured effective thermal conductivity showed to become smaller with decreasing particle size or decreasing pressure, but it was nearly independent of the bed temperature. When steam was the filler-gas, the rise in the thermal conductivity of the adsorbent particles due to steam adsorption led to the increase in the effective thermal conductivity of the bed, and this effect was not negligible at high steam pressure for the bed of large particle size. It was found that both the predictions of the effective thermal conductivity by the Hayashi et al.'s model and the Bauer-Schlünder model generally agreed well with the measurements, by considering the particle thermal conductivity rise due to steam adsorption. The thermal conductivity of a consolidated bed of granular zeolite 13X was also measured, and it was found to be much larger than that of the packed bed especially at lower pressure. The above prediction models underestimated the effective thermal conductivity of the consolidated bed.

  3. High efficiency chlorine removal from polyvinyl chloride (PVC) pyrolysis with a gas-liquid fluidized bed reactor.

    Science.gov (United States)

    Yuan, G; Chen, D; Yin, L; Wang, Z; Zhao, L; Wang, J Y

    2014-06-01

    In this research a gas-liquid fluidized bed reactor was developed for removing chlorine (Cl) from polyvinyl chloride (PVC) to favor its pyrolysis treatment. In order to efficiently remove Cl within a limited time before extensive generation of hydrocarbon products, the gas-liquid fluidized bed reactor was running at 280-320 °C, where hot N2 was used as fluidizing gas to fluidize the molten polymer, letting the molten polymer contact well with N2 to release Cl in form of HCl. Experimental results showed that dechlorination efficiency is mainly temperature dependent and 300 °C is a proper reaction temperature for efficient dechlorination within a limited time duration and for prevention of extensive pyrolysis; under this temperature 99.5% of Cl removal efficiency can be obtained within reaction time around 1 min after melting is completed as the flow rate of N2 gas was set around 0.47-0.85 Nm(3) kg(-1) for the molten PVC. Larger N2 flow rate and additives in PVC would enhance HCl release but did not change the final dechlorination efficiency; and excessive N2 flow rate should be avoided for prevention of polymer entrainment. HCl is emitted from PVC granules or scraps at the mean time they started to melt and the melting stage should be taken into consideration when design the gas-liquid fluidized bed reactor for dechlorination.

  4. A packaged pyrometer for high temperature gases

    International Nuclear Information System (INIS)

    A packaged, automated instrument for temperature measurement in high temperature gases has been developed. The instrument is based on the well established method of spectroscopic emission-absorption pyrometry or line reversal. The instrument is intended for use with gases seeded with alkali metals in the temperature range 2000-3000K. Provision has been made for simultaneous measurements at multiple wavelengths, which extends its use to the case of flows containing scattering particulates. The basic measurement is made by transilluminating the gas with radiation from a calibrated tungsten lamp of known brightness temperature. The signal from the lamp plus gas emission together with that from the gas alone and that from the reference lamp are brought sequentially to a spectrally selective detector. The gas temperature is then calculated, using the second radiation constant and the measurement wavelength which is chosen on or close to an absorption line, such that the optical depth is less than or equal to 1. An analysis has been made to extend this method to compensate for the presence of scattering particulates, and also to measure the particle temperature

  5. Urania vapor composition at very high temperatures

    International Nuclear Information System (INIS)

    Due to the chemically unstable nature of uranium dioxide its vapor composition at very high temperatures is, presently, not sufficiently studied though more experimental knowledge is needed for risk assessment of nuclear reactors. We used laser vaporization coupled to mass spectrometry of the produced vapor to study urania vapor composition at temperatures in the vicinity of its melting point and higher. The very good agreement between measured melting and freezing temperatures and between partial pressures measured on the temperature increase and decrease indicated that the change in stoichiometry during laser heating was very limited. The evolutions with temperature (in the range 2800-3400 K) of the partial pressures of the main vapor species (UO2, UO3, and UO2+) were compared with theoretically predicted evolutions for equilibrium noncongruent gas-liquid and gas-solid phase coexistences and showed very good agreement. The measured main relative partial pressure ratios around 3300 K all agree with calculated values for total equilibrium between condensed and vapor phases. It is the first time the three main partial pressure ratios above stoichiometric liquid urania have been measured at the same temperature under conditions close to equilibrium noncongruent gas-liquid phase coexistence.

  6. Effect of Distributor Design on Gas-Liquid Distribution in Monolithic Bed at High Gas/Liquid Ratios

    Institute of Scientific and Technical Information of China (English)

    周媛; AL-DAHHAN Muthanna; DUDUKOVIC Milorad; 刘辉

    2012-01-01

    Experiments were carried out to investigate the liquid flow distribution at high gas/liquid ratios in a cold model monolith bed of a 0.048 m diameter with 62 cells per cm2.Three types of distributor for the liquid distribu-tion were used to evaluate their distribution performance.Local liquid saturation in individual channels was meas-ured using 16 single-point optical fiber probes mounted inside the channels.The results indicate that 1) The optical fiber probe technique can measure phase distribution in the monolith bed;2) Liquid saturation distribution along the radial direction of the monolith bed is not uniform and the extent of non-uniformity depends on the distributor de-sign and phase velocities;and 3) The tube array distributor provides superior liquid distribution performance over the showerhead and nozzle distributors.

  7. Dynamic high-temperature-phosphor thermometry

    Energy Technology Data Exchange (ETDEWEB)

    Tobin, K.W.; Capps, G.J.; Muhs, J.D.; Smith, D.B.; Cates, M.R.

    1990-08-01

    Dynamic surface phosphor thermometry is being investigated as part of a continuing effort by the Applied Technology Division (ATD) at Oak Ridge National Laboratory (ORNL) to develop and apply thermographic phosphor technology to an ever expanding thermometry field. The purpose of this program is to develop dynamic surface phosphor thermometry to a stage where funding proposals can be strengthened by establishing a strong information base and demonstrating a sound capability. As a new technology development in an area well established by ATD/ORNL, dynamic thermometry is extremely important for high-temperature materials, superconducting materials, advanced turbomachinery, space vehicles, industrial process equipment, and other development areas. This laboratory project illustrated the technique of continuously monitoring dynamic temperature excursions using phosphor thermography. Temperature-increase rates on the order of 100 or more degrees centigrade per millisecond were measured, which illustrated a temporal response of >0.001 s. This exceeded by a factor of ten the goal or the project and gave strong encouragement for further development of the technology. Important to the project, too, was the establishment of a clear analytical base for fluorescent-ratio data. Using the results of this study, specific solutions to dynamic-temperature-measurement problems in many application areas can be developed. In addition, the dynamic-thermographic technology can be coupled with strain measurement, two-dimensional analysis, and thermometry at very high temperatures to add interrelating remote measurement tools for systems that currently cannot be effectively studied. 13 refs., 11 figs.

  8. 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.

  9. Bed disturbance via foraging fish increases bedload transport during subsequent high flows and is controlled by fish size and species

    Science.gov (United States)

    Pledger, A. G.; Rice, S. P.; Millett, J.

    2016-01-01

    Benthic foraging by fish can modify the nature and rates of fine sediment accrual and the structure and topography of coarse-grained fluvial substrates, with the potential to alter bed material characteristics, particle entrainment thresholds, and bedload transport fluxes. However, knowledge of what controls the nature, extent, and intensity of benthic foraging and the consequent influence of these controls on geomorphic impact remain rudimentary. An ex-situ experiment utilising Barbel Barbus barbus and Chub Leuciscus cephalus extended previous work by considering the role of fish size and species as controls of sediment disturbance by foraging and the implications for bed material characteristics and bedload transport. In a laboratory flume, changes in bed microtopography and structure were measured when a water-worked bed of 5.6-22.6 mm gravels was exposed to four size classes of Barbel (4-5″, 5-6″, 6-8″, 8-10″ in length) and a single size class of Chub (8-10″). In line with other studies that have investigated animal size as a control of zoogeomorphic agency, increasing the size of Barbel had a significant effect on measured disturbance and transport metrics. Specifically, the area of disturbed substrate, foraging depth, and the fish's impact on microtopographic roughness and imbrication all increased as a function of fish size. In a comparison of the foraging effects of like-sized Barbel and Chub, 8-10″ in length, Barbel foraged a larger area of the test bed and had a greater impact on microtopographic roughness and sediment structure. Relative to water-worked beds that were not foraged, bed conditioning by both species was associated with increased bedload transport during the subsequent application of high flows. However, the bedload flux after foraging by Barbel, which is a specialist benthivore, was 150% higher than that following foraging by Chub, which feed opportunistically from the bed, and the total transported mass of sediment was 98

  10. Biological phosphorus removal during high-rate, low-temperature, anaerobic digestion of wastewater

    OpenAIRE

    Ciara eKeating; Chin, Jason P.; Dermot eHughes; Panagiotis eManesiotis; Denise eCysneiros; Therese eMahony; Smith, Cindy J; John W McGrath; Vincent eO'Flaherty

    2016-01-01

    We report, for the first time, extensive biologically-mediated phosphate removal from wastewater during high-rate anaerobic digestion (AD). A hybrid sludge bed/fixed-film (packed pumice stone) reactor was employed for low-temperature (12°C) anaerobic treatment of synthetic sewage wastewater. Successful phosphate removal from the wastewater (up to 78% of influent phosphate) was observed, mediated by biofilms in the reactor. Scanning electron microscopy and energy dispersive X-ray analysis reve...

  11. Biological Phosphorus Removal During High-Rate, Low-Temperature, Anaerobic Digestion of Wastewater

    OpenAIRE

    Keating, Ciara; Chin, Jason P.; Hughes, Dermot; Manesiotis, Panagiotis; Cysneiros, Denise; Mahony, Therese; Smith, Cindy J; John W McGrath; O’Flaherty, Vincent

    2016-01-01

    We report, for the first time, extensive biologically mediated phosphate removal from wastewater during high-rate anaerobic digestion (AD). A hybrid sludge bed/fixed-film (packed pumice stone) reactor was employed for low-temperature (12°C) anaerobic treatment of synthetic sewage wastewater. Successful phosphate removal from the wastewater (up to 78% of influent phosphate) was observed, mediated by biofilms in the reactor. Scanning electron microscopy and energy dispersive X-ray analysis reve...

  12. Fiber specklegram sensors sensitivities at high temperatures

    Science.gov (United States)

    Rodriguez-Cobo, L.; Lomer, M.; Lopez-Higuera, J. M.

    2015-09-01

    In this work, the sensitivity of Fiber Specklegram Sensors to high temperatures (up to 800ºC) have been studied. Two multimode silica fibers have been introduced into a tubular furnace while a HeNe laser source was launched into a fiber edge, projecting speckle patterns to a commercial webcam. A computer generated different heating and cooling sweeps while the specklegram evolution was recorded. The achieved results exhibit a remarkably linearity in FSS's sensitivity for temperatures under 800ºC, following the thermal expansion of fused silica.

  13. Comments on theories of high temperature superconductivity

    Directory of Open Access Journals (Sweden)

    T. M. Rice

    2006-09-01

    Full Text Available   The recently discovered MgB2 superconductors have a record transition temperature for a BCS superconductor due to the high vibration frequencies associated with its light elements. The transition temperatures in the cuprate family of superconductors are much higher but these do not fit the BCS paradigm. The most promising microscopic origin for their many anomalous properties lies in magnetic pairing described by the RVB (Resonant Valence Bond ansatz. However a comprehensive theoretical description of the key anomalous properties of the cuprates remains to be an open challenge.

  14. Effect of process temperature on morphology of CNTs grown in a vertically fluidized bed reactor with Fe{sub 2}O{sub 3}/Al{sub 2}O{sub 3} catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Shukrullah, Shazia, E-mail: zshukrullah@gmail.com; Mohamed, Norani Muti, E-mail: noranimuti-mohamed@petronas.com.my; Shaharun, Maizatul Shima, E-mail: maizats@petronas.com.my [Department of Fundamental and Applied Sciences, Universiti Teknologi PETRONAS, 31750 Tronoh, Perak (Malaysia)

    2015-07-22

    Carbon nanotubes (CNTs) are one of the most researched materials due to their exceptional mechanical and electrical properties. Among the various techniques, catalytic chemical vapor deposition in a fluidized bed reactor is the most promising technique for bulk production of CNTs. To meet the demand of good quality along with the bulk production of CNTs, the effect of reaction temperature on the micro structures, morphology, diameter, quality and quantity of CNTs was investigated in these studies. CNTs were synthesized at process temperature ranging from 700-850°C by catalytic decomposition of C{sub 2}H{sub 4} on Fe{sub 2}O{sub 3}/Al{sub 2}O{sub 3} catalyst a vertical fluidized bed reactor. The microstructures of the grown CNTs at different reaction temperatures were investigated by using scanning electron microscope. The results of this study depicted a positive correlation between the average diameter of CNTs and reaction temperature. Narrow diameters (35∼40 nm) of CNTs with fewer defects were found at the low and mild temperatures, in particular 800°C. At this temperature, a dynamic equilibrium between the rate of C{sub 2}H{sub 4} decomposition and CNTs quantity was found due to maximum carbon diffusion over catalyst. The CNTs produced with Fe{sub 2}O{sub 3}/Al{sub 2}O{sub 3} catalyst wer e also exhibiting high quality with relatively small mean outer diameter and fewer surface defects.

  15. The metallurgy of high temperature alloys

    Science.gov (United States)

    Tien, J. K.; Purushothaman, S.

    1976-01-01

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

  16. Optically transparent high temperature shape memory polymers.

    Science.gov (United States)

    Xiao, Xinli; Qiu, Xueying; Kong, Deyan; Zhang, Wenbo; Liu, Yanju; Leng, Jinsong

    2016-03-21

    Optically transparent shape memory polymers (SMPs) have potential in advanced optoelectronic and other common shape memory applications, and here optically transparent shape memory polyimide is reported for the first time. The polyimide possesses a glass transition temperature (Tg) of 171 °C, higher than the Tg of other transparent SMPs reported, and the influence of molecular structure on Tg is discussed. The 120 μm thick polyimide film exhibits transmittance higher than 81% in 450-800 nm, and the possible mechanism of its high transparency is analyzed, which will benefit further research on other transparent high temperature SMPs. The transparent polyimide showed excellent thermomechanical properties and shape memory performances, and retained high optical transparency after many shape memory cycles.

  17. High temperature sensors for exhaust diagnosis

    Energy Technology Data Exchange (ETDEWEB)

    Svenningstorp, Henrik

    2000-07-01

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

  18. FLUIDIZED BED STEAM REFORMING MINERALIZATION FOR HIGH ORGANIC AND NITRATE WASTE STREAMS FOR THE GLOBAL NUCLEAR ENERGY PARTNERSHIP

    Energy Technology Data Exchange (ETDEWEB)

    Jantzen, C; Michael Williams, M

    2008-01-11

    Waste streams that may be generated by the Global Nuclear Energy Partnership (GNEP) Advanced Energy Initiative may contain significant quantities of organics (0-53 wt%) and/or nitrates (0-56 wt%). Decomposition of high nitrate streams requires reducing conditions, e.g. organic additives such as sugar or coal, to reduce the NO{sub x} in the off-gas to N{sub 2} to meet the Clean Air Act (CAA) standards during processing. Thus, organics will be present during waste form stabilization regardless of which GNEP processes are chosen, e.g. organics in the feed or organics for nitrate destruction. High organic containing wastes cannot be stabilized with the existing HLW Best Developed Available Technology (BDAT) which is HLW vitrification (HLVIT) unless the organics are removed by preprocessing. Alternative waste stabilization processes such as Fluidized Bed Steam Reforming (FBSR) operate at moderate temperatures (650-750 C) compared to vitrification (1150-1300 C). FBSR converts organics to CAA compliant gases, creates no secondary liquid waste streams, and creates a stable mineral waste form that is as durable as glass. For application to the high Cs-137 and Sr-90 containing GNEP waste streams a single phase mineralized Cs-mica phase was made by co-reacting illite clay and GNEP simulated waste. The Cs-mica accommodates up to 30% wt% Cs{sub 2}O and all the GNEP waste species, Ba, Sr, Rb including the Cs-137 transmutation to Ba-137. For reference, the cesium mineral pollucite (CsAlSi{sub 2}O{sub 6}), currently being studied for GNEP applications, can only be fabricated at {ge} 1000 C. Pollucite mineralization creates secondary aqueous waste streams and NO{sub x}. Pollucite is not tolerant of high concentrations of Ba, Sr or Rb and forces the divalent species into different mineral host phases. The pollucite can accommodate up to 33% wt% Cs{sub 2}O.

  19. Thermoelectric properties by high temperature annealing

    Science.gov (United States)

    Ren, Zhifeng (Inventor); Chen, Gang (Inventor); Kumar, Shankar (Inventor); Lee, Hohyun (Inventor)

    2009-01-01

    The present invention generally provides methods of improving thermoelectric properties of alloys by subjecting them to one or more high temperature annealing steps, performed at temperatures at which the alloys exhibit a mixed solid/liquid phase, followed by cooling steps. For example, in one aspect, such a method of the invention can include subjecting an alloy sample to a temperature that is sufficiently elevated to cause partial melting of at least some of the grains. The sample can then be cooled so as to solidify the melted grain portions such that each solidified grain portion exhibits an average chemical composition, characterized by a relative concentration of elements forming the alloy, that is different than that of the remainder of the grain.

  20. Plasma synthesis of high temperature ceramic films

    Energy Technology Data Exchange (ETDEWEB)

    Brown, I.G.; Monteiro, O.R.

    1998-11-01

    Thin films of alumina, chromia, mullite, yttria and zirconia have been synthesized using a plasma-based method called metal plasma immersion ion implantation and deposition (Mepiiid)--a highly versatile plasma deposition technique with ion energy control. Monolithic films (a single ceramic component) and multilayer films (individual layers of different ceramic materials) were formed. The films were characterized for their composition and structure in a number of different ways, and the high temperature performance of the films was explored, particularly for their ability to maintain their integrity and adhesion when subjected to repetitive high temperature thermal cycling up 1100 C. We found that the films retain their adhesion and quality without any apparent degradation with time, even after a large number of cycles; (the tests were extended out to a total of 40 cycles each of 24 hours duration). After repetitive high temperature thermal cycling, the film-substrate adhesion was greater than {approx}70 Mpa, the instrumental limit of measurement, and the interface toughness was approximately 0.8 MPa m{sup 1/2}.

  1. Electrochemical high-temperature gas sensors

    Science.gov (United States)

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

    2012-06-01

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

  2. High temperature deformation of silicon steel

    Energy Technology Data Exchange (ETDEWEB)

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

    2012-10-15

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

  3. Energy storage via high temperature superconductivity (SMES)

    Energy Technology Data Exchange (ETDEWEB)

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

    1998-10-01

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

  4. Experimental investigation and numerical modelling of cyclones for application at high temperatures. Doctoral thesis

    Energy Technology Data Exchange (ETDEWEB)

    Bernard, J.G.

    1992-11-16

    This thesis describes a part of the research project High Temperature Gas Clean-up' (HTG), specifically for application in Pressurized Fluidized Bed Combustion (PFBC). The thesis involves research on cyclones, with specific application at high temperature. The flow pattern and the behavior of the particulate phase were investigated. Since the measurements at high temperature were complicated, many introductory experiments were made at normal conditions. This was also a good starting point for the modeling of the cyclone. Models which have been developed so far were based on operation at normal conditions and were validated under the same circumstances. Therefore, it was first attempted to make reliable measurements at normal conditions before the measurements at high temperatures were assessed.

  5. Evaluation of high temperature capacitor dielectrics

    Science.gov (United States)

    Hammoud, Ahmad N.; Myers, Ira T.

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

  6. Medium Deep High Temperature Heat Storage

    Science.gov (United States)

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

    2015-04-01

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

  7. Nontrivial center dominance in high temperature QCD

    Science.gov (United States)

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

    2016-07-01

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

  8. High temperature vapor pressure of pure plutonium

    International Nuclear Information System (INIS)

    High temperature vapor pressure measurements have been made on pure plutonium metal by the Knudsen effusion technique. The reported experimental results extend into the transition region between molecular and viscous or hydrodynamic flow. Under the conditions used, linearity was observed up to temperatures in excess of 2200 K where pressures approaching 100 Pa were measured. The results over the temperature range 1724--2219 K yield log10P/sub Pu/(Pa) = (9.735 +- 0.105) -17066 +- 208/T and the enthalpy and entropy of vaporization and the standard deviations therein are ΔH0/sub v/(Pu,1975 K) =326.78 +- 3.97 kJ mol-1, ΔS0/sub v/(Pu,1975 K) =90.54 +- 2.01 J K-1 mol-1. Based on the most recently available free energy functions for plutonium liquid and gas, the values of the standard enthalpy of vaporization calculated via second- and third-law methods are ΔH0/sub v/(II, Pu,298 K) =344.14 +- 3.97 kJ mol-1, ΔH0/sub v/(III, Pu,298 K) =341.67 +- 1.26 kJ mol-1. Single crystal tungsten containers were used to hold the charge of plutonium and proved to be very satisfactory in alleviating problems of liquid metal creep and liquid/cell interactions normally encountered with actinides held at high temperatures for long periods

  9. Noise temperature in graphene at high frequencies

    Science.gov (United States)

    Rengel, Raúl; Iglesias, José M.; Pascual, Elena; Martín, María J.

    2016-07-01

    A numerical method for obtaining the frequency-dependent noise temperature in monolayer graphene is presented. From the mobility and diffusion coefficient values provided by Monte Carlo simulation, the noise temperature in graphene is studied up to the THz range, considering also the influence of different substrate types. The influence of the applied electric field is investigated: the noise temperature is found to increase with the applied field, dropping down at high frequencies (in the sub-THz range). The results show that the low-frequency value of the noise temperature in graphene on a substrate tends to be reduced as compared to the case of suspended graphene due to the important effect of remote polar phonon interactions, thus indicating a reduced emitted noise power; however, at very high frequencies the influence of the substrate tends to be significantly reduced, and the differences between the suspended and on-substrate cases tend to be minimized. The values obtained are comparable to those observed in GaAs and semiconductor nitrides.

  10. Dynamic model development and validation for a nitrifying moving bed biofilter: Effect of temperature and influent load on the performance

    DEFF Research Database (Denmark)

    Sin, Gürkan; Weijma, Jan; Spanjers, Henri;

    2008-01-01

    A mathematical model with adequate complexity integrating hydraulics, biofilm and microbial conversion processes is successfully developed for a continuously moving bed biofilter performing tertiary nitrification. The model was calibrated and validated using data from Nether Stowey pilot plant...

  11. Temperature effects on nitrogen cycling and nitrate removal-production efficiency in bed form-induced hyporheic zones

    Science.gov (United States)

    Zheng, Lizhi; Cardenas, M. Bayani; Wang, Lichun

    2016-04-01

    Hyporheic flow in aquatic sediment controls solute and heat transport thereby mediating the fate of nutrients and contaminants, dissolved oxygen, and temperature in the hyporheic zone (HZ). We conducted a series of numerical simulations of hyporheic processes within a dune with different uniform temperatures, coupling turbulent open channel fluid flow, porous fluid flow, and reactive solute transport to study the temperature dependence of nitrogen source/sink functionality and its efficiency. Two cases were considered: a polluted stream and a pristine stream. Sensitivity analysis was performed to investigate the influence of stream water [NO3-]/[NH4+]. The simulations showed that in both cases warmer temperatures resulted in shallower denitrification zones and oxic-anoxic zone boundaries, but the trend of net denitrification rate and nitrate removal or production efficiency of the HZ for these two cases differed. For both cases, at high [NO3-]/[NH4+], the HZ functioned as a NO3- sink with the nitrate removal efficiency increasing with temperature. But at low [NO3-]/[NH4+] for the polluted stream, the HZ is a NO3- sink at low temperature but then switches to a NO3- source at warmer temperatures. For the pristine stream case, the HZ was always a NO3- source, with the NO3- production efficiency increasing monotonically with temperature. In addition, although the interfacial fluid flux expectedly increased with increasing temperature due to decreasing fluid viscosity, the total nitrate flux into the HZ did not follow this trend. This is because when HZ nitrification is high, uniformly elevated [NO3-] lowers dispersive fluxes into the HZ. We found that there are numerous confounding and interacting factors that combined to lead to the final temperature dependence of N transformation reaction rates. Although the temperature effect on the rate constant can be considered as the dominant factor, simply using the Arrhenius equation to predict the reaction rate would lead to

  12. High temperature alloys: their exploitable potential

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, J.B.; Merz, M.; Nihoul, J.; Ward, J. (eds.) (Commission of the European Communities, Petten (Netherlands). Joint Nuclear Research Center; NET-TEAM, Garching (DE))

    1987-01-01

    This book is the proceedings of a conference dealing with fundamental and technical aspects of the applications of high temperature alloys. It is split into five sections which cover the opening session of the conference and four further sessions covering: the theoretical and practical limits for HT alloys; the potential for development in alloys and processing; engineering considerations; the future outlook. The different sessions each included a number of invited papers followed by a series of posters and were concluded by a presentation of a 'synthesis' by a session rapporteur and general discussion. This structure is retained in the proceedings, including the discussion points in those cases where the authors have provided written answers to the questions raised. This book will be of interest to metallurgists, materials scientists, physicists and research workers in high temperature materials.

  13. Oxidative coupling of methane in a fluidized-bed reactor over a highly active and selective catalyst

    Energy Technology Data Exchange (ETDEWEB)

    Mleczko, L.; Pannek, U. [Ruhr-Universitaet, Bochum (Germany). Lehrstuhl fuer Technische Chemie; Niemi, V.M.; Hiltunen, J. [NESTE OY, Porvoo (Finland). Technology Centre

    1996-01-01

    Oxidative coupling of methane to C{sub 2+} hydrocarbons over a Zr/La/Sr catalyst was investigated in an atmospheric-pressure shallow fluidized-bed reactor (i.d. = 5 cm; H{sub mf} = 1.4--3.2 cm) at temperatures between 800 and 880 C. The catalyst was mechanically and catalytically stable, but its fluidizability was limited; agglomeration and channeling occurred. The highest C{sub 2+} yield amounted to 18.0% (X{sub CH{sub 4}} = 36.5%, S{sub C{sub 2+}} = 49.4%) and 17.2% (X{sub CH{sub 4}} = 36.6%, S{sub C{sub 2+}} = 46.9%) for the diluted and undiluted feed, respectively. These yields are among the highest ones reported in the open literature for oxidative coupling of methane in fluidized beds. In the whole investigated temperature range higher selectivities and yields were obtained upon reducing partial pressures of methane and oxygen but keeping their ratio constant (p{sub CH{sub 4}}/p{sub O{sub 2}} = 2.5). An increased gas velocity or bed height resulted in a drop of C{sub 2+} selectivity.

  14. Intermetallic-based high-temperature materials

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.

    1999-07-01

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

  15. Intermetallic-Based High-Temperature Materials

    Energy Technology Data Exchange (ETDEWEB)

    Sikka, V.K.

    1999-04-25

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

  16. Transport properties of high critical temperature superconductors

    International Nuclear Information System (INIS)

    In this paper an overview of transport properties of the new high temperature oxide superconducting materials is presented. In particular the transport critical current in single crystals and sintered material is examined. The intrinsic properties of the new superconductors can be explained in terms of a low pinning energy and of the usual mechanisms of thermally activated flux motion. In sintered samples the superconducting behavior is dominated by the poor intergrain coupling that lead to the formation of Josephson weak links between grains

  17. High Temperature Superconducting Maglev Measurement System

    OpenAIRE

    Wang, Jia-Su; Wang, Su-Yu

    2010-01-01

    Three high temperature superconducting (HTS) Maglev measurement systems were successfully developed in the Applied Superconductivity Laboratory (ASCLab) of Southwest Jiaotong University, P. R. China. These systems include liquid nitrogen vessel, Permanent Magnet Guideway (PMG), data collection and processing, mechanical drive and Autocontrol features. This chapter described the three different measuring systems along with their theory of operations and workflow. The SCML-01 HTS Maglev measure...

  18. High Temperature Endurable Fiber Optic Accelerometer

    OpenAIRE

    Yeon-Gwan Lee; Jin-Hyuk Kim; Chun-Gon Kim

    2014-01-01

    This paper presents a low frequency fiber optic accelerometer for application in high temperature environments of civil engineering structures. The reflection-based extrinsic fiber optic accelerometer developed in this study consists of a transmissive grating panel, reflective mirror, and two optical fiber collimators as the transceiver whose function can be maintained up to 130°C. The dynamic characteristics of the sensor probe were investigated and the correlation between the natural freque...

  19. Current trends in high temperature design

    Energy Technology Data Exchange (ETDEWEB)

    Marriott, D.L. (Illinois Univ., Urbana, IL (United States). Dept. of Mechanical Engineering)

    1992-01-01

    A review of high temperature design guidelines has been carried out in preparation for designing a solar storage module for the Freedom Spacelab. Three major guidelines, N47, R5 and RCC-MR form the basis of the survey. The main issues with current, mature design in the power industry appear to be adequately covered by these guidelines. A significant finding is that long established models of material damage have survived the test of time very well. A new design regime referred to as Very High Temperature Design (VHTD) is identified. The characteristics of this regime are changing material properties which require some changes in philosophy in drafting of future codes, particularly in regard to definitions of yield strengths and other design allowables. Finally, there is some discussion of the more general use of the stress/strain plane, e.g. isochronous curves, for representation of very complex material constitutive behaviour. A concept called the 'Relaxation Locus', which summarizes essential local constrained component behavior, is introduced and its application to high temperature design problems is discussed briefly. (author).

  20. New fluid for high temperature applications

    Energy Technology Data Exchange (ETDEWEB)

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

    2006-12-15

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

  1. High temperature inorganic membranes for separating hydrogen

    Energy Technology Data Exchange (ETDEWEB)

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

    1995-08-01

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

  2. The NDT methods under high temperature service environment

    Directory of Open Access Journals (Sweden)

    Zhang Zhen-guo

    2016-01-01

    Full Text Available Concerning the detective requirement of the equipment under high temperature running status, this paper summarizes the technical characteristics and related applications of several non-destructive testing methods(NDT, such as thermal infrared imaging technology in high temperature, ultrasonic testing technique in high temperature, pulsed eddy current technology in high temperature and magnetic powder flaw detection technology in high temperature, penetration testing technique in high temperature and indirect visual detection in high temperature and on-line monitoring system in high temperature.

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

    Data.gov (United States)

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

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

    Data.gov (United States)

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

  5. High-temperature fatigue in metals

    Science.gov (United States)

    Halford, G. R.

    1982-01-01

    The presentation focuses primarily on the progress we at NASA Lewis Research Center have made. The understanding of the phenomenological processes of high temperature fatigue of metals for the purpose of calculating lives of turbine engine hot section components is discussed. Improved understanding resulted in the development of accurate and physically correct life prediction methods such as Strain-Range Partitioning for calculating creep fatigue interactions and the Double Linear Damage Rule for predicting potentially severe interactions between high and low cycle fatigue. Examples of other life prediction methods are also discussed.

  6. Gas cleaning with hot char beds studied by stable isotopes

    DEFF Research Database (Denmark)

    Egsgaard, Helge; Ahrenfeldt, Jesper; Ambus, Per;

    2014-01-01

    The chemistry taking place in a high temperature char bed used for binding aromatic tar compounds has been studied in detail. 13C labelled tar compounds were used to trace the incorporation into the char bed using isotope ratio mass spectrometry (IRMS) and GC-MS. Furthermore, compounds labelled...

  7. Physical properties of high temperature superconductors

    International Nuclear Information System (INIS)

    In this thesis, the magnetic characterization of some Bi1.6Pb0.4Sr2Ca2Cu3O10, Bi1.84Pb0.34Sr1.91Ca2.03Cu2.06O10, Tl2Ba2Ca2Cu3O10 and Bi-2212/Ag high temperature superconductors were given by ac magnetic susceptibility and electrical resistivity measuring techniques. Bi1.6Pb0.4Sr2Ca2Cu3O10 and Bi1.84Pb0.34Sr1.91Ca2.03Cu2.06O10 high temperature superconductors were prepared by liquid ammonium nitrate method, while conventional solid state reaction route was applied to make Tl2Ba2Ca2Cu3O10 superconductor. On the other hand, Powder-In Tube (PIT) technique was used to make multi-filamentary Bi-2212/Ag tapes. Structural characterizations were carried out by X-ray powder diffraction (XRD) patterns and scanning electron microscopy (SEM). Unit cell parameters of Bi1.6Pb0.4Sr2Ca2Cu3O10 and Tl2Ba2Ca2Cu3O10 high temperature superconductors which have tetragonal crystal structure were calculated as a=b=5.3538 AA and c=37.1137 AA, a=b=3.8520 AA and c=35.5970 AA respectively. The results are consistent with the literature. Some information with regards to the grain size and phase content were given by the SEM studies. Fundamental and high order ac susceptibilities, χ=χn'''+iχn''(n=1, 2, 3, 5 and 7) of the samples were measured for the temperature range 15 K-140 K, ac field range 8 A/rn-1600 A/m and the frequency range 11 Hz-2110 Hz. All the susceptibilities exhibit field, frequency and temperature dependences. The observed dependences were analyzed using Bean model. For temperature scaling a function of the form Hp=Hα(l-t)''β was found empirically. The best fitting parameters for the Bi1.6Pb0.4Sr2Ca2Cu3O10 superconductor were found as Hα 3.3x104 A/m and β=2.05. Odd-order harmonic susceptibilities were calculated from the Bean model to make comparison with the experiments. In addition, ac losses were also calculated from the Bean model to compare with the experimentally measured values. At low temperatures and fields, the Bean model is observed to account for the ac losses

  8. On-line temperature control of fluidized bed incinerator using fuzzy algorithm; Fuzzu seigyo donyu ni yoru ryudosogata shokyakuro unten no jidoka

    Energy Technology Data Exchange (ETDEWEB)

    Okayasu, S.; Kuratani, T.; Imai, H. [Ajinomoto Co. Inc., Tokyo (Japan)

    1995-03-15

    Automatic control of incinerators for their stable operation has been desired for the preservation of the environment in the factory. An on-line fuzzy control system has been successfully introduced for temperature control of the fluidized bed of incinerator for industrial wastes. In this case, manual control can be applied to the plant instead of a PID control system, because of the complexity of the waste materials and the large delay in detection of the temperature change in the fluidized bed sand. On the basis of analyzing the dynamic performance of the process and the know-how of skilled operators, membership functions and fuzzy control rules are selected, then determined carefully for the system. Introduction of the system resulted in almost the same performance as manual control. Subsequently the operators are freed from manual operation in the control room for an hour. 6 refs., 5 figs., 4 tabs.

  9. The effect of temperature and flow rate on the clarification of the aqueous stevia-extract in a fixed-bed column with zeolites

    Directory of Open Access Journals (Sweden)

    Mantovaneli I. C. C.

    2004-01-01

    Full Text Available Stevia is being used as a sweetener due to its low calorific value and its taste, which is very similar to that of sucrose. After extraction from dried leaves, stevia extract is dark in colour so needs to be clarified for better acceptance by consumers. Adsorption is one of the most important processes in this clarification. In this work the clarification of extract stevia extract in fixed-bed columns with calcium zeolites was studied. Two temperatures (10ºC and 30ºC and six different flow rates (2, 5, 9, 12, 16 and 19 mL/min were studied. The results showed that the mass-transfer coeffcient increases with an increase in flow rate and the length of unused bed reaches a maximum at 9 mL/min for both temperatures. The fit of the Thomas model with the breakthrough data was not very good.

  10. Filtration and dust cake experiment by ceramic candle filter in high temperature conditions

    Energy Technology Data Exchange (ETDEWEB)

    Chung, J.D.; Hwang, T.W.; Park, S.J. [Hoseo University, Asan (Republic of Korea)

    2003-11-01

    Particulate collection at high temperature and high pressure (HTHP) is important in an advanced coal power generation system not only to improve the thermal efficiency of the system, but also to prevent the gas turbine from erosion and to meet the emission limits of the effluent gas. The specifications for particulate collection in those systems such as Integrated Gasification Combined Cycle (IGCC) and Pressurized Fluidized Bed Combustion (PFBC) require absolutely high collection efficiency and reliability. Advanced cyclone, granular bed filter, electrostatic precipitator, and ceramic filter have been developed for particulate collection in the advanced coal power generation system. However, rigid ceramic filters and granular bed filters among them show the best potential. The problems experienced of these systems on performance, materials, and mechanical design were investigated. Ceramic candle filters have the best potential for IGCC at this moment because they have nearly the highest efficiency compared with other filtering systems and have accumulated many reliable design data from many field experiences. The purpose of this study was to investigate the efficiency of ceramic filters and stability of material against high temperature and longterm operation condition by applying fly ash on the surface of the filter and relation of pressure drop and dust cake thickness. Experimental conditions were 50 hours at 450{sup o}C, 650{sup o}C and 850{sup o}C.

  11. Process heat cogeneration using a high temperature reactor

    Energy Technology Data Exchange (ETDEWEB)

    Alonso, Gustavo, E-mail: gustavoalonso3@gmail.com [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n, Ocoyoacac, Edo. De Mexico 52750 (Mexico); Instituto Politécnico Nacional, Unidad Profesional Adolfo Lopez Mateos, Ed. 9, Lindavista, D.F. 07300 (Mexico); Ramirez, Ramon [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n, Ocoyoacac, Edo. De Mexico 52750 (Mexico); Valle, Edmundo del [Instituto Politécnico Nacional, Unidad Profesional Adolfo Lopez Mateos, Ed. 9, Lindavista, D.F. 07300 (Mexico); Castillo, Rogelio [Instituto Nacional de Investigaciones Nucleares, Carretera Mexico-Toluca s/n, Ocoyoacac, Edo. De Mexico 52750 (Mexico)

    2014-12-15

    Highlights: • HTR feasibility for process heat cogeneration is assessed. • A cogeneration coupling for HTR is proposed and process heat cost is evaluated. • A CCGT process heat cogeneration set up is also assessed. • Technical comparison between both sources of cogeneration is performed. • Economical competitiveness of the HTR for process heat cogeneration is analyzed. - Abstract: High temperature nuclear reactors offer the possibility to generate process heat that could be used in the oil industry, particularly in refineries for gasoline production. These technologies are still under development and none of them has shown how this can be possible and what will be the penalty in electricity generation to have this additional product and if the cost of this subproduct will be competitive with other alternatives. The current study assesses the likeliness of generating process heat from Pebble Bed Modular Reactor to be used for a refinery showing different plant balances and alternatives to produce and use that process heat. An actual practical example is presented to demonstrate the cogeneration viability using the fact that the PBMR is a modular small reactor where the cycle configuration to transport the heat of the reactor to the process plant plays an important role in the cycle efficiency and in the plant economics. The results of this study show that the PBMR would be most competitive when capital discount rates are low (5%), carbon prices are high (>30 US$/ton), and competing natural gas prices are at least 8 US$/mmBTU.

  12. High Temperature Materials for Chemical Propulsion Applications

    Science.gov (United States)

    Elam, Sandra; Hickman, Robert; O'Dell, Scott

    2007-01-01

    Radiation or passively cooled thrust chambers are used for a variety of chemical propulsion functions including apogee insertion, reaction control for launch vehicles, and primary propulsion for planetary spacecraft. The performance of these thrust chambers is limited by the operating temperature of available materials. Improved oxidation resistance and increased operating temperatures can be achieved with the use of thermal barrier coatings such as zirconium oxide (ZrO2) and hafnium oxide (HfO2). However, previous attempts to include these materials showed cracking and spalling of the oxide layer due to poor bonding. Current research at NASA's Marshall Space Flight Center (MSFC) has generated unique, high temperature material options for in-space thruster designs that are capable of up to 2500 C operating temperatures. The research is focused on fabrication technologies to form low cost Iridium,qF_.henium (Ir/Re) components with a ceramic hot wall created as an integral, functionally graded material (FGM). The goal of this effort is to further de?celop proven technologies for embedding a protective ceramic coating within the Ir/Re liner to form a robust functional gradient material. Current work includes the fabrication and testing of subscale samples to evaluate tensile, creep, thermal cyclic/oxidation, and thermophysical material properties. Larger test articles have also being fabricated and hot-fire tested to demonstrate the materials in prototype thrusters at 1O0 lbf thrust levels.

  13. Multichannel pyrometry applications in high temperature thermophysics

    International Nuclear Information System (INIS)

    Full Text: Temperature measurements play a key role in the measurements of thermophysical properties performed with the aid of laser heating. This technique is very often applied when the measurements are made in the vicinity of the melting point where effective spectral emissivity of the surface cannot be evaluated with the required reliability. Optical measurements are also sometimes perturbed by evaporation at very high temperatures followed by aerosol agglomeration. Moreover, rapid temperature excursions - one of the main features of the laser heating experiments - call for sufficiently fast temperature measurements. Multichannel pyrometry can be considered as an almost unique solution since it essentially increases the information about thermal radiation in respect to the conventional single or double channel pyrometry. However, this extension makes sense only if the photometric properties of each channel (dynamic range, linearity, long term stability) are similar to those of precision monochromatic pyrometers. Yet, very recently the basic opto-electronical components for this application - high-speed Si-array detectors working in conjunction with high-speed 16 bit analog-to-digital converters - became available. First results of the characterization and application of a multichannel pyrometer based on a 200-channel Si-array spectrometer with the full spectrum acquisition time of ≥0.8 ms are presented. The pyrometer consists of a complex objective, which focuses the light from the defined area of 0.3 mm in dia. at a distance of 500 mm from objective onto optical fiber. Then the light is transmitted to the spectrometer mounted on a PC computer board. An absolute calibration of the pyrometer has been performed at the wavelength 650 nm against a standard tungsten ribbon lamp. The extension of the calibration to all the spectrometer channels, covering the range of 500 - 900 nm, has been made against graphite Black-Body (BB) radiator in the temperature range of

  14. Supercell Depletion Studies for Prismatic High Temperature Reactors

    Energy Technology Data Exchange (ETDEWEB)

    J. Ortensi

    2012-10-01

    The traditional two-step method of analysis is not accurate enough to represent the neutronic effects present in the prismatic high temperature reactor concept. The long range coupling of the various regions in high temperature reactors poses a set of challenges that are not seen in either LWRs or fast reactors. Unlike LWRs, which exhibit large, localized effects, the dominant effects in PMRs are, for the most part, distributed over larger regions, but with lower magnitude. The 1-D in-line treatment currently used in pebble bed reactor analysis is not sufficient because of the 2-D nature of the prismatic blocks. Considerable challenges exist in the modeling of blocks in the vicinity of reflectors, which, for current small modular reactor designs with thin annular cores, include the majority of the blocks. Additional challenges involve the treatment of burnable poisons, operational and shutdown control rods. The use of a large domain for cross section preparation provides a better representation of the neutron spectrum, enables the proper modeling of BPs and CRs, allows the calculation of generalized equivalence theory parameters, and generates a relative power distribution that can be used in compact power reconstruction. The purpose of this paper is to quantify the effects of the reflector, burnable poison, and operational control rods on an LEU design and to delineate an analysis approach for the Idaho National Laboratory. This work concludes that the use of supercells should capture these long-range effects in the preparation of cross sections and along with a set of triangular meshes to treat BPs, and CRs a high fidelity neutronics computation is attainable.

  15. The effects of fabric for sleepwear and bedding on sleep at ambient temperatures of 17°C and 22°C

    OpenAIRE

    Shin, Mirim

    2016-01-01

    Mirim Shin,1 Mark Halaki,1 Paul Swan,2 Angus Ireland,2 Chin Moi Chow1 1Exercise, Health and Performance Research Group, Faculty of Health Sciences, The University of Sydney, Lidcombe, 2Australian Wool Innovation Limited, The Woolmark Company, Sydney, NSW, Australia Abstract: The fibers used in clothing and bedding have different thermal properties. This study aimed to investigate the influences of textile fabrics on sleep under different ambient temperature (Ta) conditions. Seventeen healthy ...

  16. The effects of fabric for sleepwear and bedding on sleep at ambient temperatures of 17°C and 22°C

    OpenAIRE

    Shin, Mirim

    2016-01-01

    Mirim Shin,1 Mark Halaki,1 Paul Swan,2 Angus Ireland,2 Chin Moi Chow1 1Exercise, Health and Performance Research Group, Faculty of Health Sciences, The University of Sydney, Lidcombe, 2Australian Wool Innovation Limited, The Woolmark Company, Sydney, NSW, Australia Abstract: The fibers used in clothing and bedding have different thermal properties. This study aimed to investigate the influences of textile fabrics on sleep under different ambient temperature (Ta) conditions. Seventeen healthy ...

  17. High temperature thruster technology for spacecraft propulsion

    Science.gov (United States)

    Schneider, Steven J.

    A technology program has been underway since 1985 to develop high temperature oxidation-resistant thrusters for spacecraft applications. The successful development of this technology will provide the basis for the design of higher performance satellite engines with reduced plume contamination. Alternatively, this technology program will provide a material with high thermal margin to operate at conventional temperatures and provide increased life for refuelable or reusable spacecraft. The new chamber material consists of a rhenium substrate coated with iridium for oxidation protection. This material increases the operating temperature of thrusters to 2200°C, a significant increase over the 1400°C of the silicide-coated niobium chambers currently used. Stationkeeping class 22 N engines fabricated from iridium-coated rhenium have demonstrated steady state specific impulses 20 to 25 seconds higher than niobium chambers. Ir-Re apogee class 440 N engines are expected to deliver an additional 10 to 15 seconds. These improved performances are obtained by reducing or eliminating the fuel film cooling requirements in the combustion chamber while operating at the same overall mixture ratio as conventional engines. The program is attempting to envelope flight qualification requirements to reduce the potential risks and costs of flight qualification programs.

  18. Reliability Analysis of High Temperature Reactor Fuels

    International Nuclear Information System (INIS)

    This paper presents the results of reliability analysis of the TRISO -coated fuel particles for the High Temperature Test Reactor (HTTR), Japan. The reliability of fuel particle was evaluated based on the failure probability of each coating layer, and only the failure due to internal gas pressure and shrinkage of pyrolytic carbon (PyC) layer was considered The analysis results show that, no significant failure occurs up to about 45 MWd/kgU for the first core fuel particle and up to about 75 MWd/kgU for the reload core fuel particle. The fuel particle is predicted to fail completely at about 50 MWd/kgU for the first core fuel particle and at about 85 MWd/kgU for the reload core fuel particle. This results show that the TRISO -coated fuel particle for the HTTR to have high reliability. No failure occurs up to the maximum burnup design level, i.e. 33 MWd/kgU for the first core fuel particle and 60 MWd/kgU for the reload core fuel particle. The analysis results show also that the fuel particle reliability (coating layers) depends on the irradiation temperature. The failure occurs at lower burnup if the irradiation temperature increases. (author)

  19. Conformal Properties in High Temperature QCD

    CERN Document Server

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

    2015-01-01

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

  20. Aerospace Applications Of High Temperature Superconductivity

    Science.gov (United States)

    Anderson, W. W.

    1988-05-01

    The existence of superconductors with TcOOK (which implies device operating temper-atures the order of Top ≍45K) opens up a variety of potential applications within the aerospace/defense industry. This is partly due to the existence of well developed cooler technologies to reach this temperature regime and partly due to the present operation of some specialized components at cryogenic temperatures. In particular, LWIR focal planes may operate at 10K with some of the signal processing electronics at an intermediate temperature of 40K. Addition of high Tc superconducting components in the latter system may be "free" in the sense of additional system complexity required. The established techniques for cooling in the 20K to 50K temperature regime are either open cycle, expendable material (stored gas with Joule-Thomson expansion, liquid cryogen or solid cryogen) or mechanical refrigerators (Stirling cycle, Brayton cycle or closed cycle Joule-Thomson). The high Tc materials may also contribute to the development of coolers through magnetically levitated bearings or providing the field for a stage of magnetic refrigeration. The discovery of materials with Tc, 90K has generated a veritable shopping list of applications. The superconductor properties which are of interest for applications are (1) zero resistance, (2) Meissner effect, (3) phase coherence and (4) existence of an energy gap. The zero resistance property is significant in the development of high field magnets requiring neglible power to maintain the field. In addition to the publicized applications to rail guns and electromagnetic launcher, we can think of space born magnets for charged particle shielding or whistler mode propagation through a plasma sheath. Conductor losses dominate attenuation and dispersion in microstrip transmission lines. While the surface impedance of a superconductor is non vanishing, significant improvements in signal transmission may be obtained. The Meissner effect may be utilized

  1. Metals behaviour at very high temperature

    International Nuclear Information System (INIS)

    The present in-situ investigations focus on the crystallographic behavior of metals in their high-temperature phase, such as the β-phase in Ti alloys or the δ-ferrite in steel. Conventional investigations involving quench unavoidably distort the high temperature lattice through phase transformations, anisotropic thermal expansion or precipitates. Neutron and synchrotron high-energy X-ray diffraction methods were used to obtain crystallographic information in-situ and in real time. Upon annealing, primary neutron extinction allows to follow the perfection of the crystal lattice as a function of time, revealing the kinetics of dislocation annihilation. Upon cooling, the precipitating a-phase distorts the lattice of the [3-phase, seen in its very early stages. Deviation from the Avrami behavior reveals changes of dimensionality of the nucleation and growth process. The intensity morphology of Debye-Scherrer rings upon high-energy X-ray diffraction allows to distinguish deformation processes in a thermo-mechanical simulation, revealing deformation by slip, dynamic recovery and recrystallization.

  2. A High-Performance Vacuum Cleaner for Bed Bug Sampling: A Useful Tool for Medical Entomology.

    Science.gov (United States)

    Bérenger, Jean-Michel; Almeras, Lionel; Leulmi, Hamza; Parola, Philippe

    2015-05-01

    Arthropods can be captured by two modes: a passive mode using traps or an active mode mainly based on the use of mouth or powered aspirators. These apparatuses are useful tools for collecting large numbers of crawling, flying, resting, or jumping arthropod specimens, particularly small specimens, such as mosquitoes or sandflies, for laboratory experiments or breeding. Different aspirator models are used to collect various arthropod specimens. However, to our knowledge, no specific system is currently available for the reliable sampling of live bed bugs in the field. Thus, we described a new system based on a classic autonomous house aspirator that requires few modifications for the collecting bed bugs. The low weight and size of this apparatus is advantageous, and it provides for rapid and secure bed bug sampling for medical entomology purposes. PMID:26334829

  3. High-Temperature Strain-And-Temperature Gauge

    Science.gov (United States)

    Wnuk, S. P.; Lanius, S. J.

    1989-01-01

    Two-element gauge used alternately in two different bridge circuits to measure both temperature and strain. Three-lead strain-and-temperature gauge developed for use at temperatures up to 750 degree F (390 degree C) on fiber-reinforced carbon/carbon composite material having coefficient of thermal expansion of 0.8 ppm/degree F. Unlike most temperature-compensated gauges, gauge gives accurate results even during rapid heating and cooling cycles. Similar gauges produced for materials with different coefficients of thermal expansion.

  4. 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

  5. Creep resistant high temperature martensitic steel

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-11-13

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

  6. High Temperature and Pressure Alkaline Electrolysis

    DEFF Research Database (Denmark)

    Allebrod, Frank

    as well as extremely caustic environments. Based on a literature study to identify resistant materials for these conditions, Inconel 600 was selected among the metals which are available for autoclave construction. An initial single atmosphere high temperature and pressure measurement setup was build...... against conventional technologies for hydrogen production, such as natural gas reforming, the production and investment costs have to be reduced. A reduction of the investment costs may be achieved by increasing the operational pressure and temperature of the electrolyzer, as this will result in: 1......) production of pressurized hydrogen and oxygen, 2) improved electrical efficiencies and 3) increased current density, i.e. increased hydrogen production rate for a given electrolyser cell area. This thesis describes an exploratory technical study mainly in order to examine the possibility to produce hydrogen...

  7. Heterogeneous metasurface for high temperature selective emission

    Energy Technology Data Exchange (ETDEWEB)

    Woolf, D., E-mail: dwoolf@psicorp.com; Hensley, J. [Physical Sciences, Inc., 20 New England Business Center, Andover, Massachusetts 01810 (United States); Cederberg, J. G.; Bethke, D. T.; Grine, A. D.; Shaner, E. A. [Sandia National Laboratories, P.O. Box 5800, Albuquerque, New Mexico 87185 (United States)

    2014-08-25

    We demonstrate selective emission from a heterogeneous metasurface that can survive repeated temperature cycling at 1300 K. Simulations, fabrication, and characterization were performed for a cross-over-a-backplane metasurface consisting of platinum and alumina layers on a sapphire substrate. The structure was stabilized for high temperature operation by an encapsulating alumina layer. The geometry was optimized for integration into a thermophotovoltaic (TPV) system, and was designed to have its emissivity matched to the external quantum efficiency spectrum of 0.6 eV InGaAs TPV material. We present spectral measurements of the metasurface that result in a predicted 22% optical-to-electrical power conversion efficiency in a simplified model at 1300 K. Furthermore, this broadly adaptable selective emitter design can be easily integrated into full-scale TPV systems.

  8. Graphite thermal expansion reference for high temperature

    Science.gov (United States)

    Gaal, P. S.

    1974-01-01

    The design requirements of the aerospace and high-temperature nuclear reactor industries necessitate reliable thermal expansion data for graphite and other carbonaceous materials. The feasibility of an acceptable reference for calibration of expansion measuring systems that operate in carbon-rich atmospheres at temperatures ranging to 2500 C is the prime subject of this work. Present-day graphite technology provides acceptable materials for stable, reproducible references, as reflected by some of the candidate materials. The repeatability for a single specimen in a given expansion measuring system was found to be plus or minus 1%, while the combined results of several tests made on a number of samples fell within a plus or minus 2.5% band.

  9. Fast response bolometer for high temperature plasma

    International Nuclear Information System (INIS)

    A fast response bolometer is developed to measure the radiation loss from a high temperature plasma. Radiation from the plasma (mainly x-ray) is absorbed by a thin foil and heats it up. Change in far infrared (FIR) radiation, due to the change in temperature, emitted from the back surface of the foil is detected by an FIR detector which is contained in a shield box placed distant from a plasma generating machine to eliminate electrical noise. The FIR radiation is transmitted from the thin foil to the detector by a light pipe (metal pipe inner surface of which is polished). The foil (radiation absorber) consists of 5μm thick copper foil, both surfaces of which are coated with 1 μm thick carbon to increase the sensitivity and to simplify the calibration procedure. Calibration is done by two methods: One is to obtain the relation between temperature of the foil and the output of the detector. The other is to measure the detector output when the foil is illuminated by a flashlight with known light energy. Latter calibration procedure is excellent in that it is reliable and can be carried out with the same arrangement as the radiation from the plasma is measured. The result of this calibration is 0.46mV/mJ. This figure can be increased by adoption of FIR light collecting system. Time response of the bolometer (conduction of heat from radiation absorbing surface to the back surface of the foil) is calculated to be 400 ns. The thickness of the foil is chosen in such a way that the radiation from the plasma with electron temperature of about 100 eV is almost completely absorbed. This bolometer is applicable to plasmas with higher temperature when the foil thickness is increased with the sacrifice of time response and sensitivity. (author)

  10. High temperature corrosion in biomass incineration plants

    Energy Technology Data Exchange (ETDEWEB)

    Gotthjaelp, K.; Broendsted, P. [Risoe National Lab., Materials Dept. (Denmark); Jansen, P.; Markussen, J. [The Force Inst., Div. for Materials and Maintenance (Denmark); Montgomery, M.; Maahn, E. [DTU, Inst. of Manufacturing Engineering, Corrosion and Surface Technology (Denmark)

    1997-03-15

    The aim of the present project is to study the role of ash deposits in high temperature corrosion of superheater materials in biomass and refuse-fired combined heat and power plants. The project has included the two main activities: A chemical characterisation of ash deposits collected from a major number of biomass and refuse-fired combined heat and power plant boilers; Laboratory exposures and metallurgical examinations of material specimens with ash deposits in well-defined gas environments with HCl and SO{sub 2} in a furnace. In the first part of the project ash deposits were collected from the radiation chamber, superheater and economizer sections in both waste incineration and straw-fired/wood chip fired power plants. Thirteen plants participated in the investigations giving a total of 52 ash deposit samples. These were analysed using SEM-EDX. For refuse incineration, predominant elements are sodium, potassium, sulphur, chlorine, magnesium and calcium and in some cases zinc and lead. For straw or wood chip fired power plants, predominant elements are chlorine, sulphur,potassium and magnesium. The laboratory experiments were conducted using the electrically heated furnace rig for gaseous exposures. Two types of high temperature resistant steels, Sandvik 8LR30 (18Cr 10Ni Ti) and Sanicro 28 (27Cr 31Ni 4Mo) were investigated at 600 deg. C and 800 deg. C flue gas temperature and at a 600 deg. C metal temperature for up to 300 hours. Specimens which were embedded in ash deposits from a straw fired power plant were exposed to HCl (200 ppm) and SO{sub 2} (300 ppm). (EG)

  11. High temperature polymer electrolyte membrane fuel cell

    Institute of Scientific and Technical Information of China (English)

    K.Scott; M. Mamlouk

    2006-01-01

    One of the major issues limiting the introduction of polymer electrolyte membrane fuel cells (PEMFCs) is the low temperature of operation which makes platinum-based anode catalysts susceptible to poisoning by the trace amount of CO, inevitably present in reformed fuel. In order to alleviate the problem of CO poisoning and improve the power density of the cell, operating at temperature above 100 ℃ is preferred. Nafion(R) -type perfluorosulfonated polymers have been typically used for PEMFC. However, the conductivity of Nafion(R) -type polymers is not high enough to be used for fuel cell operations at higher temperature ( > 90 ℃) and atmospheric pressure because they dehydrate under these condition.An additional problem which faces the introduction of PEMFC technology is that of supplying or storing hydrogen for cell operation,especially for vehicular applications. Consequently the use of alternative fuels such as methanol and ethanol is of interest, especially if this can be used directly in the fuel cell, without reformation to hydrogen. A limitation of the direct use of alcohol is the lower activity of oxidation in comparison to hydrogen, which means that power densities are considerably lower. Hence to improve activity and power output higher temperatures of operation are preferable. To achieve this goal, requires a new polymer electrolyte membrane which exhibits stability and high conductivity in the absence of liquid water.Experimental data on a polybenzimidazole based PEMFC were presented. A simple steady-state isothermal model of the fuel cell is also used to aid in fuel cell performance optimisation. The governing equations involve the coupling of kinetic, ohmic and mass transport. This paper also considers the advances made in the performance of direct methanol and solid polymer electrolyte fuel cells and considers their limitations in relation to the source and type of fuels to be used.

  12. Variations in pore characteristics in high volatile bituminous coals: Implications for coal bed gas content

    Science.gov (United States)

    Mastalerz, Maria; Drobniak, A.; Strapoc, D.; Solano-Acosta, W.; Rupp, J.

    2008-01-01

    The Seelyville Coal Member of the Linton Formation (Pennsylvanian) in Indiana was studied to: 1) understand variations in pore characteristics within a coal seam at a single location and compare these variations with changes occurring between the same coal at different locations, 2) elaborate on the influence of mineral-matter and maceral composition on mesopore and micropore characteristics, and 3) discuss implications of these variations for coal bed gas content. The coal is high volatile bituminous rank with R0 ranging from 0.57% to 0.60%. BET specific surface areas (determined by nitrogen adsorption) of the coals samples studied range from 1.8 to 22.9??m2/g, BJH adsorption mesopore volumes from 0.0041 to 0.0339??cm3/g, and micropore volumes (determined by carbon dioxide adsorption) from 0.0315 to 0.0540??cm3/g. The coals that had the largest specific surface areas and largest mesopore volumes occur at the shallowest depths, whereas the smallest values for these two parameters occur in the deepest coals. Micropore volumes, in contrast, are not depth-dependent. In the coal samples examined for this study, mineral-matter content influenced both specific surface area as well as mesopore and micropore volumes. It is especially clear in the case of micropores, where an increase in mineral-matter content parallels the decrease of micropore volume of the coal. No obvious relationships were observed between the total vitrinite content and pore characteristics but, after splitting vitrinite into individual macerals, we see that collotelinite influences both meso- and micropore volume positively, whereas collodetrinite contributes to the reduction of mesopore and micropore volumes. There are large variations in gas content within a single coal at a single location. Because of this variability, the entire thickness of the coal must be desorbed in order to determine gas content reliably and to accurately calculate the level of gas saturation. ?? 2008 Elsevier B.V. All

  13. High-temperature superconductors make major progress

    CERN Multimedia

    CERN Bulletin

    2014-01-01

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

  14. Stable Vanadium Isotope Fractionation at High Temperatures

    Science.gov (United States)

    Prytulak, J.; Parkinson, I. J.; Savage, P. S.; Nielsen, S. G.; Halliday, A. N.

    2011-12-01

    Vanadium is a redox sensitive transition metal existing in multiple valence states at terrestrial conditions. Stable vanadium isotopes (reported as δ51V in % relative to an Alfa Aesar standard [1]) are a potentially powerful tracer of oxidation-reduction processes. However, the determination of δ51V is analytically challenging, primarily due to the extreme abundance ratio between the only two stable isotopes (51V/50V ~ 400) and, also, significant isobaric interferences of 50Ti and 50Cr on the minor 50V isotope. We have developed the first method able to determine δ51V to a precision (2 s.d. ~ 0.15%, [1,2]) that enables application of this isotope system to geological processes. To usefully investigate high temperature processes using vanadium isotopes, knowledge of the isotope composition and range of values present in the ambient mantle is required. Here we discuss the first δ51V measured in igneous materials encompassing peridotites, MORB, and primitive mantle-derived melts such as picrites. This first dataset provides a preliminary reconnaissance of the magnitude of natural fractionation. We find little isotope fractionation in suites of peridotites and MORB (vanadium isotope fractionation that may be expected at high temperatures. The presence of significant isotope variation outside of analytical precision in these materials bodes well for the use of δ51V to address a variety of broad scale questions in high temperature planetary processes. [1] Nielsen, S.G., Prytulak, J., Halliday, A.N. 2011. Geost. Geoanal. Res., in press. [2] Prytulak, J., Nielsen, S.G., Halliday, A.N. 2011. Geost. Geoanal. Res., in press. [3] Parkinson and Pearce, 1998. Journal of Petrology, 39, 1577-1618. [4] Lee et al., 2005. Journal of Petrology, 46, 2313-2336. [5] Cottrell and Kelley, 2011. Earth and Planetary Sciences Letters, 305, 270-282.

  15. The effects of fabric for sleepwear and bedding on sleep at ambient temperatures of 17°C and 22°C

    Directory of Open Access Journals (Sweden)

    Shin M

    2016-04-01

    Full Text Available Mirim Shin,1 Mark Halaki,1 Paul Swan,2 Angus Ireland,2 Chin Moi Chow1 1Exercise, Health and Performance Research Group, Faculty of Health Sciences, The University of Sydney, Lidcombe, 2Australian Wool Innovation Limited, The Woolmark Company, Sydney, NSW, Australia Abstract: The fibers used in clothing and bedding have different thermal properties. This study aimed to investigate the influences of textile fabrics on sleep under different ambient temperature (Ta conditions. Seventeen healthy young participants (ten males underwent nine nights of polysomnography testing including an adaptation night. Participants were randomized to each of the three binary factors: sleepwear (cotton vs wool, bedding (polyester vs wool, and Ta (17°C vs 22°C with relative humidity set at 60%. Skin temperature (Tsk and core temperature (Tc were monitored throughout the sleep period. Sleep onset latency (SOL was significantly shortened when sleeping in wool with trends of increased total sleep time and sleep efficiency compared to cotton sleepwear. At 17°C, the proportion of sleep stages 1 (%N1 and 3 (%N3 and rapid eye movement sleep was higher, but %N2 was lower than at 22°C. Interaction effects (sleepwear × Ta showed a significantly shorter SOL for wool than cotton at 17°C but lower %N3 for wool than cotton at 22°C. A significantly lower %N2 but higher %N3 was observed for wool at 17°C than at 22°C. There was no bedding effect on sleep. Several temperature variables predicted the sleep findings in a stepwise multiple regression analysis and explained 67.8% of the variance in SOL and to a lesser degree the %N2 and %N3. These findings suggest that sleepwear played a contributory role to sleep outcomes and participants slept better at 17°C than at 22°C.Keywords: cotton, polyester, wool, polysomnography, skin temperature, core body temperature

  16. Multichannel euv spectroscopy of high temperature plasmas

    International Nuclear Information System (INIS)

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

  17. High temperature ion channels and pores

    Science.gov (United States)

    Kang, Xiaofeng (Inventor); Gu, Li Qun (Inventor); Cheley, Stephen (Inventor); Bayley, Hagan (Inventor)

    2011-01-01

    The present invention includes an apparatus, system and method for stochastic sensing of an analyte to a protein pore. The protein pore may be an engineer protein pore, such as an ion channel at temperatures above 55.degree. C. and even as high as near 100.degree. C. The analyte may be any reactive analyte, including chemical weapons, environmental toxins and pharmaceuticals. The analyte covalently bonds to the sensor element to produce a detectable electrical current signal. Possible signals include change in electrical current. Detection of the signal allows identification of the analyte and determination of its concentration in a sample solution. Multiple analytes present in the same solution may also be detected.

  18. High Temperature Sodium Thermal Convection Test Loop

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    A project for the evaluation of compatibility characteristic of structural materials used in China experimental fast reactor(CEFR) has been in operation. The conditions which these structural materials contact with liquid sodium in reactor can be simulated by the tests in high temperature sodium thermal convection test loop. The main aims of designing and constructing the thermal convection test loop is for the corrosion test of CEFR materials, and the objective is to obtain the corrosion data of domestic materials.The main features of the test loop are shown in Fig.1. The primary components of the loop

  19. High temperature quark localization by Polyakov loops

    CERN Document Server

    Kovacs, Tamas G; Bruckmann, Falk; Schierenberg, Sebastian

    2011-01-01

    We study the low eigenmodes of the overlap and staggered Dirac operator at high temperature. We show that the recently found localized quark modes obeying Poisson statistics are connected to physical gauge field objects with their size and density scaling in the continuum limit. The localized modes are also strongly correlated with large fluctuations of the Polyakov loop. Based on that we construct a random matrix model of the low Dirac modes inspired by dimensional reduction. Our model reproduces the Poisson to random matrix transition seen in the lattice Dirac spectrum.

  20. High Temperature Materials Laboratory third annual report

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-12-01

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

  1. On Silicides in High Temperature Titanium Alloys

    OpenAIRE

    Ramachandra, C.; Vakil Singh; P. Rama Rao

    1986-01-01

    High temperature titanium alloys like IMI 685 contain small amounts of silicon (~ 0.25 wt. per cent) to improve creep resistance. Different types of silicides, namely Ti5Si3 (TiZr)5Si3(S1) and (TiZr)6 Si3 (S2), have been observed to precipitate in various silicon-bearing titanium alloys depending upon their composition and heat treatment. The precipitation of silicides, their orientation relationship with the matrix in different alloys, and the beneficial influence of thermo-mechanical treatm...

  2. High power densities from high-temperature material interactions

    Energy Technology Data Exchange (ETDEWEB)

    Morris, J.F.

    1981-01-01

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

  3. DEVELOPMENT OF HIGH ACTIVITY, COAL-DERIVED, PROMOTED CATALYTIC SYSTEMS FOR NOx REDUCTION AT LOW TEMPERATURES

    Energy Technology Data Exchange (ETDEWEB)

    Joseph M. Calo

    2000-07-21

    This project is directed at an investigation of catalytic NO{sub x} reduction mechanisms on coal-derived, activated carbon supports at low temperatures. Promoted carbon systems offer some potentially significant advantages for heterogeneous NO{sub x} reduction. These include: low cost; high activity at low temperatures, which minimizes carbon loss; oxygen resistance; and a support material which can be engineered with respect to porosity, transport and catalyst dispersion characteristics. During the reporting period, the following has been accomplished: (1) Steady-state reactivity studies in the packed bed reactor were extended to the NO/CO-carbon reaction system as a function of temperature and NO and CO concentrations. It was found that the NO reaction rate increased in the presence of CO, and the apparent activation energy decreased to about 75 {+-} 8 kJ/mol. In addition, the influence of mass transfer limitations were noted at low NO and CO concentrations. (2) The packed bed reactor/gas flow system has been applied to performing post-reaction temperature programmed desorption (TPD) studies of intermediate surface complexes following steady-state reaction. It was found that the amount of CO-evolving intermediate surface complexes exceeded that of the N{sub 2}-evolving surface complexes, and that both increased with reaction temperature. The TPD spectra indicates that both types of complexes desorb late, suggesting that they have high desorption activation energies. Plans for the next reporting period include extending the temperature programmed desorption studies in the packed bed reactor system to the NO/CO reaction system, including exposure to just CO, as well as NO/CO mixtures.

  4. High-resolution ice thickness and bed topography of a land-terminating section of the Greenland Ice Sheet

    DEFF Research Database (Denmark)

    Lindbäck, K.; Pettersson, R.; Doyle, S. H.;

    2014-01-01

    . The covered area is one of the most studied regions of the Greenland Ice Sheet with studies of mass balance, dynamics, and supraglacial lakes, and our combined dataset can be valuable for detailed studies of ice sheet dynamics and hydrology. The compiled datasets of ground-based and airborne radar surveys......We present ice thickness and bed topography maps with high spatial resolution (250 to 500 m) of a and-terminating section of the Greenland Ice Sheet derived from combined ground-based and airborne radar surveys. The data have a total area of ~12000 km2 and cover the whole ablation area...... of the outlet glaciers of Isunnguata Sermia, Russell, Leverett, Ørkendalen and Isorlersuup up to the long-term mass balance equilibrium line altitude at ~1600 m above sea level. The bed topography shows highly variable subglacial trough systems, and the trough of the Isunnguata Sermia Glacier is over...

  5. Fluidized bed electrodes with high carbon loading for water desalination by capacitive deionization

    NARCIS (Netherlands)

    Doornbusch, G.J.; Dykstra, J.E.; Biesheuvel, P.M.; Suss, M.E.

    2016-01-01

    The use of carbon flow electrodes has significantly impacted electrochemical energy storage and capacitive deionization (CDI), but device performance is limited as these electrodes cannot surpass ∼20 wt% carbon while maintaining flowability. We here introduce flowable fluidized bed electrodes whi

  6. 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...

  7. Multiphysics methods development for high temperature gas reactor analysis

    Science.gov (United States)

    Seker, Volkan

    Multiphysics computational methods were developed to perform design and safety analysis of the next generation Pebble Bed High Temperature Gas Cooled Reactors. A suite of code modules was developed to solve the coupled thermal-hydraulics and neutronics field equations. The thermal-hydraulics module is based on the three dimensional solution of the mass, momentum and energy equations in cylindrical coordinates within the framework of the porous media method. The neutronics module is a part of the PARCS (Purdue Advanced Reactor Core Simulator) code and provides a fine mesh finite difference solution of the neutron diffusion equation in three dimensional cylindrical coordinates. Coupling of the two modules was performed by mapping the solution variables from one module to the other. Mapping is performed automatically in the code system by the use of a common material mesh in both modules. The standalone validation of the thermal-hydraulics module was performed with several cases of the SANA experiment and the standalone thermal-hydraulics exercise of the PBMR-400 benchmark problem. The standalone neutronics module was validated by performing the relevant exercises of the PBMR-268 and PBMR-400 benchmark problems. Additionally, the validation of the coupled code system was performed by analyzing several steady state and transient cases of the OECD/NEA PBMR-400 benchmark problem.

  8. Analytic Models of High-Temperature Hohlraums

    International Nuclear Information System (INIS)

    A unified set of high-temperature-hohlraum models has been developed. For a simple hohlraum, Ps = (As+(1minusαW)AW+AH)σTR4 + (4Vσ/c)(dTRr/dt) where PS is the total power radiated by the source, As is the source area, AW is the area of the cavity wall excluding the source and holes in the wall, AH is the area of the holes, σ is the Stefan-Boltzmann constant, TR is the radiation brightness temperature, V is the hohlraum volume, and c is the speed of light. The wall albedo αW triplebond (TW/TR)4 where TW is the brightness temperature of area AW. The net power radiated by the source PN = PS-ASσTR4, which suggests that for laser-driven hohlraums the conversion efficiency ηCE be defined as PN/PLASER. The characteristic time required to change TR4 in response to a change in PN is 4V/C((lminusαW)AW+AH). Using this model, TR, αW, and ηCE can be expressed in terms of quantities directly measurable in a hohlraum experiment. For a steady-state hohlraum that encloses a convex capsule, PN = {(1minusαW)AW+AH+((1minus C)(AS+AWαW)AC/AT= )}σTRC4 where αC is the capsule albedo, AC is the capsule area, AT triplebond (AS+AW+AH), and TRC is the brightness temperature of the radiation that drives the capsule. According to this relation, the capsule-coupling efficiency of the baseline National-Ignition-Facility (NIF) hohlraum is 15% higher than predicted by previous analytic expressions. A model of a hohlraum that encloses a z pinch is also presented

  9. Cyclic operation of a fixed-bed pressure and temperature swing process for CO2 capture: Experimental and statistical analysis

    OpenAIRE

    García López, Susana; Gil Matellanes, María Victoria; Pis Martínez, José Juan; Rubiera González, Fernando; Pevida García, Covadonga

    2013-01-01

    An adsorption process that effectively separates CO2 from high pressure CO2/H2 shift gas streams to meet the requirements of pre-combustion CO2 capture has been evaluated. A commercial activated carbon, Norit R2030CO2, was used as the adsorbent material and different batchwise regeneration conditions were investigated. Statistical analysis by means of response surface methodology (RSM) was employed to assess the combined effect of three independent variables, namely, desorption temperature (T...

  10. 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...

  11. Note: High temperature pulsed solenoid valve.

    Science.gov (United States)

    Shen, Wei; Sulkes, Mark

    2010-01-01

    We have developed a high temperature pulsed solenoid valve with reliable long term operation to at least 400 degrees C. As in earlier published designs, a needle extension sealing a heated orifice is lifted via solenoid actuation; the solenoid is thermally isolated from the heated orifice region. In this new implementation, superior sealing and reliability were attained by choosing a solenoid that produces considerably larger lifting forces on the magnetically actuated plunger. It is this property that facilitates easily attainable sealing and reliability, albeit with some tradeoff in attainable gas pulse durations. The cost of the solenoid valve employed is quite low and the necessary machining quite simple. Our ultimate level of sealing was attained by making a simple modification to the polished seal at the needle tip. The same sealing tip modification could easily be applied to one of the earlier high T valve designs, which could improve the attainability and tightness of sealing for these implementations. PMID:20113132

  12. Aerospace applications of high temperature superconductivity

    Science.gov (United States)

    Connolly, D. J.; Heinen, V. O.; Aron, P. R.; Lazar, J.; Romanofsky, Robert R.

    1990-01-01

    A review is presented of all the applications that are part of the NASA program to develop space technology capitalizing on the potential benefit of high temperature superconducting materials. The applications in three major areas are being pursued: sensors and cryogenic systems, space communications, and propulsion and power systems. This review places emphasis on space communications applications and the propulsion and power applications. It is concluded that the power and propulsion applications will eventually be limited by structural considerations rather than by the availability of suitable superconductors. A cursory examination of structural limitations implied by the virial theorem suggested that there is an upper limit to the size of high field magnetic systems that are feasible in space.

  13. High-Temperature Ionization in Protoplanetary Disks

    CERN Document Server

    Desch, Steven J

    2015-01-01

    We calculate the abundances of electrons and ions in the hot (> 500 K), dusty parts of protoplanetary disks, treating for the first time the effects of thermionic and ion emission from the dust grains. High-temperature ionization modeling has involved simply assuming that alkali elements such as potassium occur as gas-phase atoms and are collisionally ionized following the Saha equation. We show that the Saha equation often does not hold, because free charges are produced by thermionic and ion emission and destroyed when they stick to grain surfaces. This means the ionization state depends not on the first ionization potential of the alkali atoms, but rather on the grains' work functions. The charged species' abundances typically rise abruptly above about 800 K, with little qualitative dependence on the work function, gas density, or dust-to-gas mass ratio. Applying our results, we find that protoplanetary disks' dead zone, where high diffusivities stifle magnetorotational turbulence, has its inner edge locat...

  14. High-temperature Ionization in Protoplanetary Disks

    Science.gov (United States)

    Desch, Steven J.; Turner, Neal J.

    2015-10-01

    We calculate the abundances of electrons and ions in the hot (≳500 K), dusty parts of protoplanetary disks, treating for the first time the effects of thermionic and ion emission from the dust grains. High-temperature ionization modeling has involved simply assuming that alkali elements such as potassium occur as gas-phase atoms and are collisionally ionized following the Saha equation. We show that the Saha equation often does not hold, because free charges are produced by thermionic and ion emission and destroyed when they stick to grain surfaces. This means the ionization state depends not on the first ionization potential of the alkali atoms, but rather on the grains’ work functions. The charged species’ abundances typically rise abruptly above about 800 K, with little qualitative dependence on the work function, gas density, or dust-to-gas mass ratio. Applying our results, we find that protoplanetary disks’ dead zone, where high diffusivities stifle magnetorotational turbulence, has its inner edge located where the temperature exceeds a threshold value ≈1000 K. The threshold is set by ambipolar diffusion except at the highest densities, where it is set by Ohmic resistivity. We find that the disk gas can be diffusively loaded onto the stellar magnetosphere at temperatures below a similar threshold. We investigate whether the “short-circuit” instability of current sheets can operate in disks and find that it cannot, or works only in a narrow range of conditions; it appears not to be the chondrule formation mechanism. We also suggest that thermionic emission is important for determining the rate of Ohmic heating in hot Jupiters.

  15. Filter unit for use at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Ciliberti, D.F.; Lippert, T.E.

    1988-04-05

    A filtering unit for the filtering of particulates from a particulate-containing high temperature gas stream is described comprising a ceramic, tubular filter element, having a closed bottom and side walls and an open top at the upper region thereof, disposed in an aperture in a tube sheet. The walls of the tube sheet about the aperature have an inwardly extending flange thereon, with the open top of the ceramic, tubular filter element adjacent one surface of the tube sheet where filtered gases are discharged, and the closed bottom and side walls exposed to the area of the opposite surface of the tube sheet where a particulate-containing high temperature gas stream to be filtered is present. A ceramic spiral spring is provided at an end of the ceramic, tubular filter element to bias the upper region of the ceramic, tubular filter element into contact with the flange so as to seal the ceramic, tubular filter element to the flange on the tube sheet.

  16. High temperature electrochemical corrosion rate probes

    Energy Technology Data Exchange (ETDEWEB)

    Bullard, Sophie J.; Covino, Bernard S., Jr.; Holcomb, Gordon R.; Ziomek-Moroz, M.

    2005-09-01

    Corrosion occurs in the high temperature sections of energy production plants due to a number of factors: ash deposition, coal composition, thermal gradients, and low NOx conditions, among others. Electrochemical corrosion rate (ECR) probes have been shown to operate in high temperature gaseous environments that are similar to those found in fossil fuel combustors. ECR probes are rarely used in energy production plants at the present time, but if they were more fully understood, corrosion could become a process variable at the control of plant operators. Research is being conducted to understand the nature of these probes. Factors being considered are values selected for the Stern-Geary constant, the effect of internal corrosion, and the presence of conductive corrosion scales and ash deposits. The nature of ECR probes will be explored in a number of different atmospheres and with different electrolytes (ash and corrosion product). Corrosion rates measured using an electrochemical multi-technique capabilities instrument will be compared to those measured using the linear polarization resistance (LPR) technique. In future experiments, electrochemical corrosion rates will be compared to penetration corrosion rates determined using optical profilometry measurements.

  17. Development of High Temperature Gas Sensor Technology

    Science.gov (United States)

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

    1997-01-01

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

  18. Nano copper based high temperature solder alternative

    Science.gov (United States)

    Sharma, Akshay

    Nano Cu an alternative to high temperature solder is developed by the Advance Technological Center at the Lockheed Martin Corporation. A printable paste of Cu nano particles is developed with an ability to fuse at 200°C in reflow oven. After reflow the deposited material has nano crystalline and nano porous structure which affects its properties. Accelerated test are performed on nano Cu deposition having nano porous and nano crystalline structure for assessment and prediction of reliability. Nano Cu assemblies with different bond layer thickness are sheared to calculate the strength of the material and are correlated with the porous and crystalline structure of nano Cu. Thermal and isothermal fatigue test are performed on nano Cu to see the dependency of life on stress and further surface of failed assemblies were observed to determine the type of failure. Creep test at RT are performed to find the type of creep mechanism and how they are affected when subjected to high temperature. TEM, SEM, X-ray, C-SAM and optical microscopy is done on the nano Cu sample for structure and surface analysis.

  19. Hole-doped cuprate high temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

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

    2015-07-15

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

  20. High dietary sodium chloride causes further protein loss during head-down tilt bed rest (HDBR)

    Science.gov (United States)

    Buehlmeier, Judith; Frings-Meuthen, Petra; Baecker, Natalie; Stehle, Peter; Heer, Martina

    Human spaceflight is associated with a loss of body protein most likely caused by muscle degradation. Additionally astronauts tend towards a high dietary intake of sodium chloride (NaCl), which has recently been shown to induce low grade metabolic acidosis (Frings-Meuthen et al. JBMR, Epub 2007). In several patterns, e.g. chronical renal failure, metabolic acidosis is associated with protein catabolism. We therefore hypothesized that high dietary intake of NaCl enforces protein losses in HDBR, a model for physiological changes in microgravity (µG). Eight healthy male subjects (mean age 26.25 ± 3.5; mean body weight: 78.5 ± 4.1 kg) participated in a 14-day bed rest study in the metabolic ward of the DLR - Institute of Aerospace Medicine, Cologne, Germany. The study was carried out in a cross over design, consisting of two phases, each lasting 22 days (5 days adaptation, 14 days 6° HDBR and 3 days recovery). Both study phases were identical with respect to environmental conditions and study protocol. Subjects received an individually tailored, weight-maintaining diet containing 1.3 g protein/kg/day. The diet was identical in both study phases with the exception of NaClintake: Every subject received a low NaCl diet (0.7 mmol/kg/day) in one phase and a high NaCl diet (7.7 mmol/kg/day) in another one. Blood gas for analysis of acid-base balance was implemented at days 4 and 5 of adaptation, days 2, 5, 7, 10, 12, 14 of HDBR and days 2, 3 of recovery. Continuous urine collection started on the first day in the metabolic ward to analyze nitrogen excretion. Nitrogen balance was calculated from the difference between protein intake and urinary nitrogen excretion, determined by use of chemiluminescence (Grimble et al. JPEN, 1988). Plasma pH did not change significantly (p=0.285), but plasma bicarbonate and base excess decreased (p=0.0175; p=0.0093) with high NaCl intake in HDBR compared to the low NaCl diet. Nitrogen balance in HDBR was negative, as expected in

  1. Investigations for a model experiment on quenching of debris bed

    International Nuclear Information System (INIS)

    Within the frame of a severe nuclear accident research project funded by the Federal Ministry for Education, Science, Research and Technology (BMBF) the problem of heat and mass transfer in a debris bed is investigated theoretically and experimentally. Model-oriented single-effect experiments, both steady state but especially quenching experiments shall be carried out. First exploratory quenching tests were performed with small-scale (300 cm3) inductively heated beds composed of carbon steel balls and contained in various types of crucibles. Initial bed temperatures ranged from 300 to 800 degree C, in particular cases the bed temperatures were raised up to 1300 degree C. Test results obtained so far demonstrate the complexity of the phenomena and the many influencing parameters, among others size of particles, bed temperature, and type of crucible. The integrity of an appropriate test vessel, both diamagnetic and of sufficiently high resistance against thermal stress, is a major problem

  2. Fluidized bed calciner apparatus

    Science.gov (United States)

    Owen, Thomas J.; Klem, Jr., Michael J.; Cash, Robert J.

    1988-01-01

    An apparatus for remotely calcining a slurry or solution feed stream of toxic or hazardous material, such as ammonium diurante slurry or uranyl nitrate solution, is disclosed. The calcining apparatus includes a vertical substantially cylindrical inner shell disposed in a vertical substantially cylindrical outer shell, in which inner shell is disposed a fluidized bed comprising the feed stream material to be calcined and spherical beads to aid in heat transfer. Extending through the outer and inner shells is a feed nozzle for delivering feed material or a cleaning chemical to the beads. Disposed in and extending across the lower portion of the inner shell and upstream of the fluidized bed is a support member for supporting the fluidized bed, the support member having uniform slots for directing uniform gas flow to the fluidized bed from a fluidizing gas orifice disposed upstream of the support member. Disposed in the lower portion of the inner shell are a plurality of internal electric resistance heaters for heating the fluidized bed. Disposed circumferentially about the outside length of the inner shell are a plurality of external heaters for heating the inner shell thereby heating the fluidized bed. Further, connected to the internal and external heaters is a means for maintaining the fluidized bed temperature to within plus or minus approximately 25.degree. C. of a predetermined bed temperature. Disposed about the external heaters is the outer shell for providing radiative heat reflection back to the inner shell.

  3. High pressure/high temperature thermogravimetric apparatus. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Calo, J.M.; Suuberg, E.M.

    1999-12-01

    The purpose of this instrumentation grant was to acquire a state-of-the-art, high pressure, high temperature thermogravimetric apparatus (HP/HT TGA) system for the study of the interactions between gases and carbonaceous solids for the purpose of solving problems related to coal utilization and applications of carbon materials. The instrument that we identified for this purpose was manufactured by DMT (Deutsche Montan Technologies)--Institute of Cokemaking and Coal Chemistry of Essen, Germany. Particular features of note include: Two reactors: a standard TGA reactor, capable of 1100 C at 100 bar; and a high temperature (HT) reactor, capable of operation at 1600 C and 100 bar; A steam generator capable of generating steam to 100 bar; Flow controllers and gas mixing system for up to three reaction gases, plus a separate circuit for steam, and another for purge gas; and An automated software system for data acquisition and control. The HP/TP DMT-TGA apparatus was purchased in 1996 and installed and commissioned during the summer of 1996. The apparatus was located in Room 128 of the Prince Engineering Building at Brown University. A hydrogen alarm and vent system were added for safety considerations. The system has been interfaced to an Ametek quadruple mass spectrometer (MA 100), pumped by a Varian V250 turbomolecular pump, as provided for in the original proposed. With this capability, a number of gas phase species of interest can be monitored in a near-simultaneous fashion. The MS can be used in a few different modes. During high pressure, steady-state gasification experiments, it is used to sample, measure, and monitor the reactant/product gases. It can also be used to monitor gas phase species during nonisothermal temperature programmed reaction (TPR) or temperature programmed desorption (TPD) experiments.

  4. High Intensity Exercise Countermeasures does not Prevent Orthostatic Intolerance Following Prolonged Bed Rest

    Science.gov (United States)

    Platts, Steven H.; Stenger, Michael B.; Ploutz-Snyder, Lori L.; Lee, Stuart M. C.

    2014-01-01

    Approximately 20% of Space Shuttle astronauts became presyncopal during operational stand and 80deg head-up tilt tests, and the prevalence of orthostatic intolerance increases after longer missions. Greater than 60% of the US astronauts participating in Mir and early International Space Station missions experienced presyncope during post-flight tilt tests, perhaps related to limitations of the exercise hardware that prevented high intensity exercise training until later ISS missions. The objective of this study was to determine whether an intense resistive and aerobic exercise countermeasure program designed to prevent cardiovascular and musculoskeletal deconditioning during 70 d of bed rest (BR), a space flight analog, would protect against post-BR orthostatic intolerance. METHODS Twenty-six subjects were randomly assigned to one of three groups: non-exercise controls (n=11) or one of two exercise groups (ExA, n=8; ExB, n=7). Both ExA and ExB groups performed the same resistive and aerobic exercise countermeasures during BR, but one exercise group received testosterone supplementation while the other received a placebo during BR in a double-blinded fashion. On 3 d/wk, subjects performed lower body resistive exercise and 30 min of continuous aerobic exercise (=75% max heart rate). On the other 3 d/wk, subjects performed only highintensity, interval-style aerobic exercise. Orthostatic intolerance was assessed using a 15-min 80? head-up tilt test performed 2 d (BR-2) before and on the last day of BR (BR70). Plasma volume was measured using carbon monoxide rebreathing on BR-3 and before rising on the first recovery day (BR+0). The code for the exercise groups has not been broken, and results are reported here without group identification. RESULTS Only one subject became presyncopal during tilt testing on BR-2, but 7 of 11 (63%) controls, 3 of 8 (38%) ExA, and 4 of 7 (57%) ExB subjects were presyncopal on BR70. Survival analysis of post-BR tilt tests revealed no

  5. Materials for High-Temperature Catalytic Combustion

    Energy Technology Data Exchange (ETDEWEB)

    Ersson, Anders

    2003-04-01

    Catalytic combustion is an environmentally friendly technique to combust fuels in e.g. gas turbines. Introducing a catalyst into the combustion chamber of a gas turbine allows combustion outside the normal flammability limits. Hence, the adiabatic flame temperature may be lowered below the threshold temperature for thermal NO{sub X} formation while maintaining a stable combustion. However, several challenges are connected to the application of catalytic combustion in gas turbines. The first part of this thesis reviews the use of catalytic combustion in gas turbines. The influence of the fuel has been studied and compared over different catalyst materials. The material section is divided into two parts. The first concerns bimetallic palladium catalysts. These catalysts showed a more stable activity compared to their pure palladium counterparts for methane combustion. This was verified both by using an annular reactor at ambient pressure and a pilot-scale reactor at elevated pressures and flows closely resembling the ones found in a gas turbine combustor. The second part concerns high-temperature materials, which may be used either as active or washcoat materials. A novel group of materials for catalysis, i.e. garnets, has been synthesised and tested in combustion of methane, a low-heating value gas and diesel fuel. The garnets showed some interesting abilities especially for combustion of low-heating value, LHV, gas. Two other materials were also studied, i.e. spinels and hexa aluminates, both showed very promising thermal stability and the substituted hexa aluminates also showed a good catalytic activity. Finally, deactivation of the catalyst materials was studied. In this part the sulphur poisoning of palladium, platinum and the above-mentioned complex metal oxides has been studied for combustion of a LHV gas. Platinum and surprisingly the garnet were least deactivated. Palladium was severely affected for methane combustion while the other washcoat materials were

  6. High temperature steam gasification of wastewater sludge

    International Nuclear Information System (INIS)

    High temperature steam gasification is one of the most promising, viable, effective and efficient technology for clean conversion of wastes to energy with minimal or negligible environmental impact. Gasification can add value by transforming the waste to low or medium heating value fuel which can be used as a source of clean energy or co-fired with other fuels in current power systems. Wastewater sludge is a good source of sustainable fuel after fuel reforming with steam gasification. The use of steam is shown to provide value added characteristics to the sewage sludge with increased hydrogen content as well total energy. Results obtained on the syngas properties from sewage sludge are presented here at various steam to carbon ratios at a reactor temperature of 1173 K. Effect of steam to carbon ratio on syngas properties are evaluated with specific focus on the amounts of syngas yield, syngas composition, hydrogen yield, energy yield, and apparent thermal efficiency. The apparent thermal efficiency is similar to cold gas efficiency used in industry and was determined from the ratio of energy in syngas to energy in the solid sewage sludge feedstock. A laboratory scale semi-batch type gasifier was used to determine the evolutionary behavior of the syngas properties using calibrated experiments and diagnostic facilities. Results showed an optimum steam to carbon ratio of 5.62 for the range of conditions examined here for syngas yield, hydrogen yield, energy yield and energy ratio of syngas to sewage sludge fuel. The results show that steam gasification provided 25% increase in energy yield as compared to pyrolysis at the same temperature.

  7. Ceramic membranes for high temperature hydrogen separation

    Energy Technology Data Exchange (ETDEWEB)

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

    1996-08-01

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

  8. High emissivity coatings for high temperature application: Progress and prospect

    Energy Technology Data Exchange (ETDEWEB)

    He Xiaodong, E-mail: hexd@hit.edu.c [Center for Composite Materials, School of Astronautics, Harbin Institute of Technology, P.O. Box 3010, Harbin 150080 (China); Li Yibin [Center for Composite Materials, School of Astronautics, Harbin Institute of Technology, P.O. Box 3010, Harbin 150080 (China); Wang Lidong [Center for Composite Materials, School of Astronautics, Harbin Institute of Technology, P.O. Box 3010, Harbin 150080 (China); School Materials Science and Engineering, Harbin Institute of Technology, P.O. Box 405, Harbin 150001 (China); Sun Yue [Center for Composite Materials, School of Astronautics, Harbin Institute of Technology, P.O. Box 3010, Harbin 150080 (China); Zhang, Sam [School of Mechanical and Aerospace Engineering, Nanyang Technological University, 50 Nanyang Avenue, Singapore 639798 (Singapore)

    2009-07-01

    High emissivity coatings are widely used in many cases where heat transfers through electromagnetic radiation that arises due to the temperature of a body. Extensive theoretical and experimental efforts have been made to synthesize and investigate high emissivity coatings. The emissivity can be improved through various or combined mechanisms. The characterization of the emissivity is still a fully open problem. In this paper, we review the various mechanisms associated with the emissivity enhancement and emissivity characterization techniques. Based on these literature reviews, the prospect will be presented in the concluding remarks.

  9. High temperature, high vacuum facility for heavy ion simulation studies

    International Nuclear Information System (INIS)

    A high vacuum irradiation facility for heavy ion simulation studies with a tandem accelerator is described. Specimen irradiations are performed at vacuums of less than 10-8 Torr. The samples are heated to temperatures as high as 11000C by a thermal radiation heater. Partial pressure analysis reveals that H2, H2O and CO are the main constituents (approximately 97 percent) of the vacuum. Smaller amounts of CO2, CH4 and C2H4 (approximately 3 percent total) are also present. Beam charge state distribution and beam purity are measured by Rutherford scattering from a gold foil. Beam current densities and profiles are also measured

  10. Ceramic high temperature receiver design and tests

    Science.gov (United States)

    Davis, S. B.

    1982-01-01

    The High Temperature Solar Thermal Receiver, which was tested a Edwards AFB, CA during the winter of 1980-1981, evolved from technologies developed over a five year period of work. This receiver was tested at the Army Solar Furnace at White Sands, NM in 1976. The receiver, was tested successfully at 1768 deg F and showed thermal efficiencies of 85%. The results were sufficiently promising to lead ERDA to fund our development and test of a 250 kW receiver to measure the efficiency of an open cavity receiver atop a central tower of a heliostat field. This receiver was required to be design scalable to 10, 50, and 100 MW-electric sizes to show applicability to central power tower receivers. That receiver employed rectagular silicon carbide panels and vertical stanchions to achieve scalability. The construction was shown to be fully scalable; and the receiver was operated at temperatures up to 2000 deg F to achieve the performance goals of the experiment during tests at the GIT advanced components test facility during the fall of 1978.

  11. Robust high temperature oxygen sensor electrodes

    DEFF Research Database (Denmark)

    Lund, Anders

    conducting gadolinium-doped cerium oxide (CGO). The addition of CGO was found to decrease the polarisation resistance of the oxygen reaction by up to an order of magnitude compared with a single phase platinum electrode by increasing the effective triple phase boundary (TPB) length. It did not have any......Platinum is the most widely used material in high temperature oxygen sensor electrodes. However, platinum is expensive and the platinum electrode may, under certain conditions, suffer from poisoning, which is detrimental for an oxygen sensor. The objective of this thesis is to evaluate electrode...... materials as candidates for robust oxygen sensor electrodes. The present work focuses on characterising the electrochemical properties of a few electrode materials to understand which oxygen electrode processes are limiting for the response time of the sensor electrode. Three types of porous platinum...

  12. High Temperature Resistant Exhaust Valve Spindle

    DEFF Research Database (Denmark)

    Bihlet, Uffe Ditlev

    of the engine, new high temperature alloys are required for a specific engine component, the exhaust valve spindle. Two alloys are used for an exhaust valve spindle; one for the bottom of the spindle, and one for the spindle seat. Being placed in the exhaust gas stream, combustion products such as V2O5 and Na2...... of the current valve seat alloy, Alloy 718 (Ni-based, 19 wt% Cr, 18 wt% Fe, 5.1 wt% Nb, 3 wt% Mo, 1 wt% Ti and 0.6 wt% Al), and thereby to obtain a more hot corrosion resistant alloy. To validate these calculations, 16 Ni-based alloys, containing 40 wt% Cr and Nb, Ta and Ti in varying levels, were produced...

  13. High temperature and pressure electrochemical test station

    DEFF Research Database (Denmark)

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

    2013-01-01

    An electrochemical test station capable of operating at pressures up to 100 bars and temperatures up to 400 ◦C has been established. It enables control of the partial pressures and mass flow of O2, N2, H2, CO2, and H2O in a single or dual environment arrangement, measurements with highly corrosive...... media, as well as localized sampling of gas evolved at the electrodes for gas analysis. A number of safety and engineering design challenges have been addressed. Furthermore, we present a series of electrochemical cell holders that have been constructed in order to accommodate different types of cells...... and facilitate different types of electrochemical measurements. Selected examples of materials and electrochemical cells examined in the test station are provided, ranging from the evaluation of the ionic conductivity of liquid electrolytic solutions immobilized in mesoporous ceramic structures...

  14. On Silicides in High Temperature Titanium Alloys

    Directory of Open Access Journals (Sweden)

    C. Ramachandra

    1986-04-01

    Full Text Available High temperature titanium alloys like IMI 685 contain small amounts of silicon (~ 0.25 wt. per cent to improve creep resistance. Different types of silicides, namely Ti5Si3 (TiZr5Si3(S1 and (TiZr6 Si3 (S2, have been observed to precipitate in various silicon-bearing titanium alloys depending upon their composition and heat treatment. The precipitation of silicides, their orientation relationship with the matrix in different alloys, and the beneficial influence of thermo-mechanical treatment on the distribution of silicides have been pointed out. The effect of silicides on mechanical properties and fracture of the commercial alloy IMI 685 is also indicated.

  15. High temperature chemically resistant polymer concrete

    Science.gov (United States)

    Sugama, T.; Kukacka, L.E.

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

  16. HIGH TEMPERATURE OXIDATION PERFORMANCE OF ALUMINIDE COATINGS

    Energy Technology Data Exchange (ETDEWEB)

    Pint, B.A.; Zhang, Y.; Haynes, J.A.; Wright, I.G.

    2003-04-22

    In order to determine the potential benefits and limitations of aluminide coatings, coatings made by chemical vapor deposition (CVD) on Fe- and Ni-base alloy substrates are being evaluated in various high-temperature environments. Testing of coatings on representative ferritic (Fe-9Cr-1Mo) and austenitic (type 304L stainless steel) alloys has found that high frequency thermal cycling (1h cycle time) can significantly degrade the coating. Based on comparison with similar specimens with no thermal cycling or a longer cycle time (100h), this degradation was not due to Al loss from the coating but most likely because of the thermal expansion mismatch between the coating and the substrate. Several coated Ni-base alloys were tested in a high pressure (20atm) steam-CO2 environment for the ZEST (zero-emission steam turbine) program. Coated specimens showed less mass loss than the uncoated specimens after 1000h at 900 C and preliminary characterization examined the post-test coating structure and extent of attack.

  17. The effects of fabric for sleepwear and bedding on sleep at ambient temperatures of 17°C and 22°C.

    Science.gov (United States)

    Shin, Mirim; Halaki, Mark; Swan, Paul; Ireland, Angus H; Chow, Chin Moi

    2016-01-01

    The fibers used in clothing and bedding have different thermal properties. This study aimed to investigate the influences of textile fabrics on sleep under different ambient temperature (T a) conditions. Seventeen healthy young participants (ten males) underwent nine nights of polysomnography testing including an adaptation night. Participants were randomized to each of the three binary factors: sleepwear (cotton vs wool), bedding (polyester vs wool), and T a (17°C vs 22°C with relative humidity set at 60%). Skin temperature (T sk) and core temperature (T c) were monitored throughout the sleep period. Sleep onset latency (SOL) was significantly shortened when sleeping in wool with trends of increased total sleep time and sleep efficiency compared to cotton sleepwear. At 17°C, the proportion of sleep stages 1 (%N1) and 3 (%N3) and rapid eye movement sleep was higher, but %N2 was lower than at 22°C. Interaction effects (sleepwear × T a) showed a significantly shorter SOL for wool than cotton at 17°C but lower %N3 for wool than cotton at 22°C. A significantly lower %N2 but higher %N3 was observed for wool at 17°C than at 22°C. There was no bedding effect on sleep. Several temperature variables predicted the sleep findings in a stepwise multiple regression analysis and explained 67.8% of the variance in SOL and to a lesser degree the %N2 and %N3. These findings suggest that sleepwear played a contributory role to sleep outcomes and participants slept better at 17°C than at 22°C. PMID:27217803

  18. A highly efficient polyampholyte hydrogel sorbent based fixed-bed process for heavy metal removal in actual industrial effluent.

    Science.gov (United States)

    Zhou, Guiyin; Luo, Jinming; Liu, Chengbin; Chu, Lin; Ma, Jianhong; Tang, Yanhong; Zeng, Zebing; Luo, Shenglian

    2016-02-01

    High sorption capacity, high sorption rate, and fast separation and regeneration for qualified sorbents used in removing heavy metals from wastewater are urgently needed. In this study, a polyampholyte hydrogel was well designed and prepared via a simple radical polymerization procedure. Due to the remarkable mechanical strength, the three-dimensional polyampholyte hydrogel could be fast separated, easily regenerated and highly reused. The sorption capacities were as high as 216.1 mg/g for Pb(II) and 153.8 mg/g for Cd(II) owing to the existence of the large number of active groups. The adsorption could be conducted in a wide pH range of 3-6 and the equilibrium fast reached in 30 min due to its excellent water penetration for highly accessible to metal ions. The fixed-bed column sorption results indicated that the polyampholyte hydrogel was particularly effective in removing Pb(II) and Cd(II) from actual industrial effluent to meet the regulatory requirements. The treatment volumes of actual smelting effluent using one fixed bed column were as high as 684 bed volumes (BV) (7736 mL) for Pb(II) and 200 BV (2262 mL) for Cd(II). Furthermore, the treatment volumes of actual smelting effluent using tandem three columns reached 924 BV (31,351 mL) for Pb(II) and 250 BV (8483 mL) for Cd(II), producing only 4 BV (136 mL) eluent. Compared with the traditional high density slurry (HDS) process with large amount of sludge, the proposed process would be expected to produce only a small amount of sludge. When the treatment volume was controlled below 209.3 BV (7103 mL), all metal ions in the actual industrial effluent could be effectively removed (removal of heavy metal ions from practical wastewater.

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

    Energy Technology Data Exchange (ETDEWEB)

    Vinayak N. Kabadi

    2000-05-01

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

  20. Pulse Radiolysis at High Temperatures and High Pressures

    DEFF Research Database (Denmark)

    Christensen, H.; Sehested, Knud

    1981-01-01

    A set-up enabling pulse radiolysis measurements at high temperatures (up to 320°C) and high pressures (up to 140 bar) has been constructed in collaboration between Risö National Laboratory and Studsvik Energiteknik. The cell has been used for experiments with aqueous solutions with the purpose...... to determine activation energies for reactions of importance in reactor chemistry. The activation energy of the reaction e−aq+e−aq has been determined to be 22 kJ·mol−1 (5.3 kcal·mol−1) in good agreement with literature values. Furthermore, the activation energies of the reactions Cu2++OH (13.3 kJ·mol−1, 3.......2 kcal.mol−1) and OH+OH (tentatively 8 kJ·mol−1, 1.9 kcal·mol−1) have been determined. The absorption spectrum of the OH radical has been determined up to temperatures of 200°C. The absorption maximum is found at 230 nm at all temperatures. The reaction between Fe2+ and OH radicals has been studied up...

  1. High Temperature Integrated Thermoelectric Ststem and Materials

    Energy Technology Data Exchange (ETDEWEB)

    Mike S. H. Chu

    2011-06-06

    The final goal of this project is to produce, by the end of Phase II, an all ceramic high temperature thermoelectric module. Such a module design integrates oxide ceramic n-type, oxide ceramic p-type materials as thermoelectric legs and oxide ceramic conductive material as metalizing connection between n-type and p-type legs. The benefits of this all ceramic module are that it can function at higher temperatures (> 700 C), it is mechanically and functionally more reliable and it can be scaled up to production at lower cost. With this all ceramic module, millions of dollars in savings or in new opportunities recovering waste heat from high temperature processes could be made available. A very attractive application will be to convert exhaust heat from a vehicle to reusable electric energy by a thermoelectric generator (TEG). Phase I activities were focused on evaluating potential n-type and p-type oxide compositions as the thermoelectric legs. More than 40 oxide ceramic powder compositions were made and studied in the laboratory. The compositions were divided into 6 groups representing different material systems. Basic ceramic properties and thermoelectric properties of discs sintered from these powders were measured. Powders with different particles sizes were made to evaluate the effects of particle size reduction on thermoelectric properties. Several powders were submitted to a leading thermoelectric company for complete thermoelectric evaluation. Initial evaluation showed that when samples were sintered by conventional method, they had reasonable values of Seebeck coefficient but very low values of electrical conductivity. Therefore, their power factors (PF) and figure of merits (ZT) were too low to be useful for high temperature thermoelectric applications. An unconventional sintering method, Spark Plasma Sintering (SPS) was determined to produce better thermoelectric properties. Particle size reduction of powders also was found to have some positive benefits

  2. A batteryless temperature sensor based on high temperature sensitive material

    OpenAIRE

    Bakkali, Asma; Pelegrí Sebastiá, José; Laghmich, Youssef; Lyhyaoui, Abdelouahid

    2016-01-01

    The original publication is available at www.epjap.org The major challenge in wireless sensor networks is the reduction of energy consumption. Passive wireless sensor network is an attractive solution for measuring physical parameters in harsh environment for large range of applications requiring sensing devices with low cost of fabrication, small size and long term measurement stability. Batteryless temperature sensing techniques are an active research field. The a...

  3. Oxidation of Volatile Organic Compounds in a Multifunctional High Temperature and High-Pressure Cassette Microreactor

    OpenAIRE

    VAJGLOVÁ, Zuzana

    2013-01-01

    Analysis of the total oxidation of ethanol including reaction intermediates data obtained in the examined reactors on the temperature showed that differentmaterial applied in the construction of reactors and their arrangement give slightly different results of catalyst testing, the ones obtained from microreactor being more precise. More precise control of reaction temperature due to higher heat transfer capabilities and limited backmixing of reaction mixture in a packed bed microreactor is...

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

    Energy Technology Data Exchange (ETDEWEB)

    Uribe, F.

    1997-04-01

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

  5. Potential approaches to improve gasification of high water content biomass rich in cellulose in dual fluidized bed

    Energy Technology Data Exchange (ETDEWEB)

    Dong, Li; Xu, Guangwen [State Key Laboratory of Multiphase Complex System, Institute of Process Engineering, Chinese Academy of Sciences, Beijing (China); Suda, Toshiyuki [Research Laboratory, IHI Corporation, Ltd., Yokohama (Japan); Murakami, Takahiro [National Institute of Advanced Science and Technology, Tsukuba (Japan)

    2010-08-15

    Biomass containing water of 30-65 wt.% and rich in cellulose, such as various grounds of drinking materials and the lees of spirit and vinegar, is not suitable for biological digestion, and the thermal conversion approach has to be applied to its conversion into bioenergy. The authors have recently worked on converting such biomass into middle heating-value gas via dual fluidized bed gasification (DFBG) integrated with various process intensification technologies. This article is devoted to highlighting those technical ways, including the choice of the superior technical deployment for a DFBG system, the impregnation of Ca onto fuel in fuel drying, the integration of gas cleaning with fuel gasification via two-stage DFBG (T-DFBG), and the decoupling of fuel drying/pyrolysis and char gasification via the decoupled DFBG (D-DFBG). The attained results demonstrated that the superior deployment of bed combination for the DFBG should be a bubbling/turbulent fluidized bed gasifier integrated with a pneumatic riser combustor. In terms of improving efficiency of fuel conversion into combustible gas and suppressing tar generation during gasification, the impregnation of Ca onto fuel exhibited distinctively high upgrading effect, while both the T-DFBG and D-DFBG were also demonstrated to be effective to a certain degree. (author)

  6. High temperature superconductors at optimal doping

    Directory of Open Access Journals (Sweden)

    W. E. Pickett

    2006-09-01

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

  7. High temperature superconductors in electromagnetic applications

    CERN Document Server

    Richens, P E

    2000-01-01

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

  8. 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.

  9. Geochemistry of Aluminum in High Temperature Brines

    Energy Technology Data Exchange (ETDEWEB)

    Benezeth, P.; Palmer, D.A.; Wesolowski, D.J.

    1999-05-18

    The objective ofthis research is to provide quantitative data on the equilibrium and thermodynamic properties of aluminum minerals required to model changes in permeability and brine chemistry associated with fluid/rock interactions in the recharge, reservoir, and discharge zones of active geothermal systems. This requires a precise knowledge of the thermodynamics and speciation of aluminum in aqueous brines, spanning the temperature and fluid composition rangesencountered in active systems. The empirical and semi-empirical treatments of the solubility/hydrolysis experimental results on single aluminum mineral phases form the basis for the ultimate investigation of the behavior of complex aluminosilicate minerals. The principal objective in FY 1998 was to complete the solubility measurements on boehmite (AIOOH) inNaC1 media( 1 .O and 5.0 molal ionic strength, IOO-250°C). However, additional measurements were also made on boehmite solubility in pure NaOH solutions in order to bolster the database for fitting in-house isopiestic data on this system. Preliminary kinetic Measurements of the dissolution/precipitation of boehmite was also carried out, although these were also not planned in the earlier objective. The 1999 objectives are to incorporate these treatments into existing codes used by the geothermal industry to predict the chemistry ofthe reservoirs; these calculations will be tested for reliability against our laboratory results and field observations. Moreover, based on the success of the experimental methods developed in this program, we intend to use our unique high temperature pH easurement capabilities to make kinetic and equilibrium studies of pH-dependent aluminosilicate transformation reactions and other pH-dependent heterogeneous reactions.

  10. Thermal-hydraulic system study of a high pressure, high temperature helium loop using RELAP5-3D code

    International Nuclear Information System (INIS)

    Highlights: ► A thermal-hydraulic system analysis for a high pressure, high temperature helium loop has been investigated. ► The loop belongs to the Helium Loop Karlsruhe (HELOKA) facility, which contains the European Helium Cooled Pebble Beds Test Blanket Module (HCPB TBM) as the test module. ► The loop including all components has been modeled using the system code REALP5-3D, and the main control strategy has been implemented as well. ► With this model, the loop dynamics in conditions relevant for blanket module operation have been demonstrated. - Abstract: The thermal-hydraulic system analysis for the Helium Loop Karlsruhe (HELOKA) facility, a high pressure, high temperature experimental helium loop having the European Helium Cooled Pebble Beds Test Blanket Module (HCPB TBM) as the test module, was investigated. Using the system code REALP5-3D, all components in the loop are modeled as well as the main control strategy. With this model, the loop dynamics in conditions relevant for blanket module operation are simulated and analyzed.

  11. Release of K, Cl, and S during combustion and co-combustion with wood of high-chlorine biomass in bench and pilot scale fuel beds

    DEFF Research Database (Denmark)

    Johansen, Joakim Myung; Aho, Martti; Paakkinen, Kari;

    2013-01-01

    and partitioning of these elements. Earlier work by the authors on the release of K, Cl, and S from a high-chlorine biomass (corn stover) in a lab-scale setup is, in the present work, supplemented with novel results from a bench-scale fixed bed reactor and a 100kW moving grate pilot facility. The results from...... the bench-scale reactor indicate that S and K release are not significantly affected by secondary reactions, while Cl is partly recaptured by secondary reactions in the char. A linear increase in K-release was observed from 50% at 906°C to almost 80wt.% at 1234°C when firing only corn stover. A similar...... release profile was observed for Cl, from 65% to nearly 100%. Complete release of S was achieved at 1234°C with a linear increase from 70% at 906°C. Co-combustion of corn stover with low-Cl wood chips served to increase the bed temperature, resulting in complete and close to complete release of Cl and S...

  12. High-temperature high-pressure gas cleanup with ceramic bag filters. Draft final report

    Energy Technology Data Exchange (ETDEWEB)

    Shackleton, M.; Chang, R.; Sawyer, J.; Kuby, W.; Turner-Tamiyasu, E.

    1982-12-06

    Advanced processes designed for the efficient use of coal in the production of energy will benefit from, or even depend upon, highly efficient, economical, high-temperature removal systems for fine particulates. In the case of pressurized fluidized-bed combustion (PFBC), the hot gas cleanup device must operate at approximately 1600/sup 0/F. Existing commercial filter systems are temperature limited due to the filter material, but ceramic fibers intended for refractory insulation offer the promise of a practical high-temperature filter media if they can be incorporated into a design which combines filter performance with acceptable durability. The current work was initiated to further develop and demonstrate on a larger-scale basis, a ceramic fiber filtration system for application to coal-fired PFBC's. The development effort centered around the need to replace the knit metal wire scrim, used in earlier designs as support for the fine fiber ceramic mat filtration medium, with a corrosion-resistant material. This led to the selection of woven ceramic cloth for support of the mat layer. Because of the substantial difference in strength and other material properties between the metal and ceramic cloth, tests were necessary to optimize the filter; pulse parameters such as pulse duration, pulse pressure, and pulse injection orifice size; woven cloth mesh configuration; the technique for clamping the bag to the support; and similar structural, fluid, and control parameters. The demonstration effort included both tests to prove this concept in a real application and a systems analysis to show commercial feasibility of the ceramic filtration approach for hot gas cleanup in PFBC's. 12 references, 57 figures, 23 tables.

  13. Material Control and Accounting Design Considerations for High-Temperature Gas Reactors

    Energy Technology Data Exchange (ETDEWEB)

    Trond Bjornard; John Hockert

    2011-08-01

    The subject of this report is domestic safeguards and security by design (2SBD) for high-temperature gas reactors, focusing on material control and accountability (MC&A). The motivation for the report is to provide 2SBD support to the Next Generation Nuclear Plant (NGNP) project, which was launched by Congress in 2005. This introductory section will provide some background on the NGNP project and an overview of the 2SBD concept. The remaining chapters focus specifically on design aspects of the candidate high-temperature gas reactors (HTGRs) relevant to MC&A, Nuclear Regulatory Commission (NRC) requirements, and proposed MC&A approaches for the two major HTGR reactor types: pebble bed and prismatic. Of the prismatic type, two candidates are under consideration: (1) GA's GT-MHR (Gas Turbine-Modular Helium Reactor), and (2) the Modular High-Temperature Reactor (M-HTR), a derivative of Areva's Antares reactor. The future of the pebble-bed modular reactor (PBMR) for NGNP is uncertain, as the PBMR consortium partners (Westinghouse, PBMR [Pty] and The Shaw Group) were unable to agree on the path forward for NGNP during 2010. However, during the technology assessment of the conceptual design phase (Phase 1) of the NGNP project, AREVA provided design information and technology assessment of their pebble bed fueled plant design called the HTR-Module concept. AREVA does not intend to pursue this design for NGNP, preferring instead a modular reactor based on the prismatic Antares concept. Since MC&A relevant design information is available for both pebble concepts, the pebble-bed HTGRs considered in this report are: (1) Westinghouse PBMR; and (2) AREVA HTR-Module. The DOE Office of Nuclear Energy (DOE-NE) sponsors the Fuel Cycle Research and Development program (FCR&D), which contains an element specifically focused on the domestic (or state) aspects of SBD. This Material Protection, Control and Accountancy Technology (MPACT) program supports the present work

  14. The experimental investigation on the performance of a low temperature waste heat-driven multi-bed desiccant dehumidifier (MBDD) and minimization of entropy generation

    KAUST Repository

    Myat, Aung

    2012-06-01

    We present the experimental investigation on the performance of multi-bed desiccant dehumidification system (MBDD) using a thermodynamic framework with an entropy generation analysis. The cyclic steady state performance of adsorption-desorption processes at the assorted heat source temperatures, and typical ambient humidity conditions was carried out. MBDD unit uses type-RD silica gel pore surface area with of 720 m 2/g. It has a nominal diameter range of 0.4 to 0. 7 mm. The key advantages of MBDD are: (i) it has no moving parts rendering less maintenance, (ii) energy-efficient means of dehumidification by adsorption process with low temperature heat source as compared to the conventional methods, (iii) although it is a pecked bed desiccant, a laminar chamber is employed by arranging the V-shaped configuration of heat exchangers and (iv) it is environmental friendly with the low-carbon footprint. Entropy generation analysis was performed at the assorted heat source temperatures to investigate the performance of MBDD. By conducting the entropy minimization, it is now able to locate the optimal operating conditions of the system while the specific entropy generation is found to be minimal. This analysis shows that the minimization of entropy generation in the dehumidification cycle leads to the maximization of COP in the MBDD and thus, higher delivery of useful effects at the same input resources. © 2011 Elsevier Ltd. All rights reserved.

  15. Laser Brazing of High Temperature Braze Alloy

    Science.gov (United States)

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

    2000-01-01

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

  16. Control and experimental characterization of a methanol reformer for a 350 W high temperature polymer electrolyte membrane fuel cell system

    DEFF Research Database (Denmark)

    Andreasen, Søren Juhl; Kær, Søren Knudsen; Sahlin, Simon Lennart

    2013-01-01

    This work presents a control strategy for controlling the methanol reformer temperature of a 350 W high temperature polymer electrolyte membrane fuel cell system, by using a cascade control structure for reliable system operation. The primary states affecting the methanol catalyst bed temperature......% at the nominal reformer operating temperatures. As expected increasing temperatures also increase the dry gas CO content of the reformate gas and decreases the methanol slip. The hydrogen content of the gas was measured at around 73% with 25% CO2.......This work presents a control strategy for controlling the methanol reformer temperature of a 350 W high temperature polymer electrolyte membrane fuel cell system, by using a cascade control structure for reliable system operation. The primary states affecting the methanol catalyst bed temperature...... is the water and methanol mixture fuel flow and the burner fuel/air ratio and combined flow. An experimental setup is presented capable of testing the methanol reformer used in the Serenergy H3 350 Mobile Battery Charger; a high temperature polymer electrolyte membrane (HTPEM) fuel cell system...

  17. The effect of temperature and flow rate on the clarification of the aqueous stevia-extract in a fixed-bed column with zeolites

    OpenAIRE

    Mantovaneli I. C. C.; Ferretti E. C.; Simões M. R.; Silva C. Ferreira da

    2004-01-01

    Stevia is being used as a sweetener due to its low calorific value and its taste, which is very similar to that of sucrose. After extraction from dried leaves, stevia extract is dark in colour so needs to be clarified for better acceptance by consumers. Adsorption is one of the most important processes in this clarification. In this work the clarification of extract stevia extract in fixed-bed columns with calcium zeolites was studied. Two temperatures (10ºC and 30ºC) and six different flow r...

  18. Fast Pyrolysis Behavior of Banagrass as a Function of Temperature and Volatiles Residence Time in a Fluidized Bed Reactor.

    Directory of Open Access Journals (Sweden)

    Trevor James Morgan

    Full Text Available A reactor was designed and commissioned to study the fast pyrolysis behavior of banagrass as a function of temperature and volatiles residence time. Four temperatures between 400 and 600°C were examined as well as four residence times between ~1.0 and 10 seconds. Pyrolysis product distributions of bio-oil, char and permanent gases were determined at each reaction condition. The elemental composition of the bio-oils and chars was also assessed. The greatest bio-oil yield was recorded when working at 450°C with a volatiles residence time of 1.4 s, ~37 wt% relative to the dry ash free feedstock (excluding pyrolysis water. The amounts of char (organic fraction and permanent gases under these conditions are ~4 wt% and 8 wt% respectively. The bio-oil yield stated above is for 'dry' bio-oil after rotary evaporation to remove solvent, which results in volatiles and pyrolysis water being removed from the bio-oil. The material removed during drying accounts for the remainder of the pyrolysis products. The 'dry' bio-oil produced under these conditions contains ~56 wt% carbon which is ~40 wt% of the carbon present in the feedstock. The oxygen content of the 450°C, 1.4 s 'dry' bio-oil is ~38 wt%, which accounts for ~33 wt% of the oxygen in the feedstock. At higher temperature or longer residence time less bio-oil and char is recovered and more gas and light volatiles are produced. Increasing the temperature has a more significant effect on product yields and composition than increasing the volatiles residence time. At 600°C and a volatiles residence time of 1.2 seconds the bio-oil yield is ~21 wt% of the daf feedstock, with a carbon content of 64 wt% of the bio-oil. The bio-oil yield from banagrass is significantly lower than from woody biomass or grasses such as switchgrass or miscanthus, but is similar to barley straw. The reason for the low bio-oil yield from banagrass is thought to be related to its high ash content (8.5 wt% dry basis and high

  19. High Temperature Electrical Insulation Materials for Space Applications Project

    Data.gov (United States)

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

  20. Measuring Specific Heats at High Temperatures

    Science.gov (United States)

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

    1987-01-01

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

  1. Preparation of high temperature resistance polybenzimidazole resin

    Institute of Scientific and Technical Information of China (English)

    Baoshu CHEN; Daocheng LUAN; Gaopeng JIAO; Ding ZHAO; Yonghui ZHU

    2009-01-01

    Polybenzimidazole's (PBI) was synthesized from 3,3'-diaminobenzidine and adipic acid by melting copolycondensation. Its thermal properties have been studied The molecular structure and thermal stability of the resulting polymers were characterized by means of FTIR, TGA and DSC. The results indicate that the melting temperature of the PBI is higher than 400℃ and the polymer possesses excellent thermal stability. The onset decomposition temperature was determined to be 516℃, and the highest decomposition temperature reaches 536℃.

  2. Electronic phase separation and high temperature superconductors

    International Nuclear Information System (INIS)

    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

  3. Electronic phase separation and high temperature superconductors

    Energy Technology Data Exchange (ETDEWEB)

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

    1994-01-11

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

  4. High-temperature archeointensity measurements from Mesopotamia

    Science.gov (United States)

    Gallet, Yves; Le Goff, Maxime

    2006-01-01

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

  5. High-temperature spreading kinetics of metals

    Energy Technology Data Exchange (ETDEWEB)

    Rauch, N.

    2005-05-15

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

  6. Model for high rate gas flows in deformable and reactive porous beds

    Energy Technology Data Exchange (ETDEWEB)

    Weston, A M

    1985-01-08

    This report presents the development of a one dimensional planar Lagrange hydrodynamic computer model which describes the processes preceding detonation. The model treats gas flow, deflagration, and compaction in a porous bed of reactive material. The early part of deflagration to detonation experiment with porous HMX is simulated. Sensitivity of the simulation calculation to ignition and burn rate parameters is illustrated and discussed. The effects of changing the mean particle size of the porous material are investigated. There is widespread interest in runaway reaction hazards that may be associated with porosity in propellant and explosive materials. Experimentally, such reactions are initiated and observed in long, thick walled hollow tubes, filled with a granular porous bed of reactive material. We will present comparisons with an experiment on porous HMX to illustrate details of the model and to point out what we believe are important features of the observed phenomenon. A geometric finite element cell is devised that allows gas to flow through a compacting matrix. The experimental simulation considers the DDT process from initial squib burn through the onset of general matrix deflagration (convective burning), to the development of a fully dense compaction wave. While this simulation did not calculate turnover to detonation, it did illustrate that the transition occurred as soon as the compaction wave became fully dense. It is shown that deflagration and gas permeation lags compaction at the time of transition. This suggests that the actual transition involves an additional compaction dependent process. 18 references, 20 figures, 3 tables.

  7. Porosity Effect in the Core Thermal Hydraulics for Ultra High Temperature Gas-cooled Reactor

    Directory of Open Access Journals (Sweden)

    Motoo Fumizawa

    2008-12-01

    Full Text Available This study presents an experimental method of porosity evaluation and a predictive thermal-hydraulic analysis with packed spheres in a nuclear reactor core. The porosity experiments were carried out in both a fully shaken state with the closest possible packing and in a state of non-vibration. The predictive analysis considering the fixed porosity value was applied as a design condition for an Ultra High Temperature Reactor Experiment (UHTREX. The thermal-hydraulic computer code was developed and identified as PEBTEMP. The highest outlet coolant temperature of 1316 oC was achieved in the case of an UHTREX at Los Alamos Scientific Laboratory, which was a small scale UHTR. In the present study, the fuel was changed to a pebble type, a porous media. In order to compare the present pebble bed reactor and UHTREX, a calculation based on HTGR-GT300 was carried out in similar conditions with UHTREX; in other words, with an inlet coolant temperature of 871oC, system pressure of 3.45 MPa and power density of 1.3 w/cm3. As a result, the fuel temperature in the present pebble bed reactor showed an extremely lower value compared to that of UHTREX.

  8. Critical Temperature Characteristics of Layered High-Temperature Superconductor Under Pressure

    Institute of Scientific and Technical Information of China (English)

    LIANG Fang-Ying

    2009-01-01

    We consider a Ginzburg-Landau modified model of layered high-temperature superconductor under pres-sure. We have theoretically studied the relation between the pressure and the temperature of layered high-temperature superconductor. If the pressure is not a constant, we have a relation of quadratic equation between the pressure and the temperature of layered high-temperature superconductor. In a special case, we find the critical temperature decreases with further increasing pressure. In another special case, the critical temperature increases with further increasing pressure.

  9. Adsorptive Removal of Trichloroethylene in Water by Crop Residue Biochars Pyrolyzed at Contrasting Temperatures: Continuous Fixed-Bed Experiments

    OpenAIRE

    Ming Zhang; Mahtab Ahmad; Al-Wabel, Mohammad I.; Meththika Vithanage; Anushka Upamali Rajapaksha; Hyuck Soo Kim; Sang Soo Lee; Yong Sik Ok

    2015-01-01

    Biochar (BC) has attracted great attention as an alternative sorbent to activated carbon (AC). Objective of this study was to determine trichloroethylene (TCE) removal by soybean stover BC pyrolyzed at 300 (BC300) and 700°C (BC700) in continuous fixed-bed column. Columns packed with BC300, BC700, and AC reached breakthrough time in 1.1, 27.0, and 50.7 h, respectively. BC700 had higher TCE adsorption capacity than BC300 due to its higher surface area, nonpolarity, and aromaticity. The sorption...

  10. Evaluation of proposed German safety criteria for high-temperature gas-cooled reactors

    Energy Technology Data Exchange (ETDEWEB)

    Barsell, A.W.

    1980-05-01

    This work reviews proposed safety criteria prepared by the German Bundesministerium des Innern (BMI) for future licensing of gas-cooled high-temperature reactor (HTR) concepts in the Federal Republic of Germany. Comparison is made with US General Design Criteria (GDCs) in 10CFR50 Appendix A and with German light water reactor (LWR) criteria. Implications for the HTR design relative to the US design and safety approach are indicated. Both inherent characteristics and design features of the steam cycle, gas turbine, and process heat concepts are taken into account as well as generic design options such as a pebble bed or prismatic core.

  11. Electromagnetic losses in a three-phase high temperature superconducting cable determined by calorimetric measurements

    DEFF Research Database (Denmark)

    Traeholt, C.; Veje, E.; Tønnesen, Ole

    2002-01-01

    A 10 m long high temperature superconducting (HTS) cable conductor was placed in a plane three-phase arrangement. The test-bed enabled us to study the conductor losses for different separations between the phases. The superconductor was fixed symmetrically in the centre, whilst the two outer...... conventional phases (600 mm2 Cu) could be moved in the plane. It was possible to vary the inter-phase distance (centre to centre distance) from 9 to 48 cm. The HTS cable conductor was placed in a stainless steel cryostat and cooled with flowing liquid nitrogen (LN2). The losses were determined using...

  12. Characteristics and utilisation of high-temperature (HTHP) filter dusts from pfb gasification of biomass

    Energy Technology Data Exchange (ETDEWEB)

    Ranta, J. [VTT Energy, Espoo (Finland)

    1996-12-31

    The aim of the study was to survey characteristics, utilisation and possible environmental impacts of solid wastes, i.e., in case of biomass, mainly high-temperature filter ash (HTHP) from pressurised fluidised-bed gasification (PFBG). The aim is to utilise solid wastes (slag, filter dust, additives) from biomass gasification instead of dumping. One alternative is recycling to the soil as liming material or fertiliser. It is expected that the ash recycled to forest soils changes the environment less than non-recycled ash. (orig.) 3 refs.

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

    International Nuclear Information System (INIS)

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2013-10-15

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

  15. Effect of high sodium intake during 14 days of bed-rest on acid-base balance

    Science.gov (United States)

    Frings, P.; Baecker, N.; Heer, M.

    Lowering mechanical load like in microgravity is the dominant stimulus leading to bone loss However high dietary sodium intake is also considered as a risk factor for osteoporosis and thereby might exacerbate the microgravity induced bone loss In a metabolic balance non bed-rest study we have recently shown that a very high sodium intake leads to an increased bone resorption most likely because of a mild metabolic acidosis Frings et al FASEB J 19 5 A1345 2005 To test if mild metabolic acidosis also occurs during immobilization we examined the effect of increased dietary sodium on bone metabolism and acid-base balance in eight healthy male test subjects mean age 26 25 pm 3 49 years body weight 77 98 pm 4 34 kg in our metabolic ward during a 14-day head-down tilt HDT bed-rest study The study was designed as a randomized crossover study with two study periods Each period was divided into three parts 4 ambulatory days with 200 mmol sodium intake 14 days of bed-rest with either 550 mmol or 50 mmol sodium intake and 3 recovery days with 200 mmol sodium intake The sodium intake was altered by variations in dietary sodium chloride content Blood pH P CO2 and P O2 were analyzed in fasting morning fingertip blood samples several times during the entire study Bicarbonate HCO 3 - and base excess BE were calculated according to the Henderson-Hasselbach equation Preliminary results in the acid-base balance from the first study period 4 subjects with 550 mmol and 4 subjects with 50 mmol sodium intake strongly

  16. Ultra-High Temperature Distributed Wireless Sensors

    Energy Technology Data Exchange (ETDEWEB)

    May, Russell; Rumpf, Raymond; Coggin, John; Davis, Williams; Yang, Taeyoung; O' Donnell, Alan; Bresnahan, Peter

    2013-03-31

    Research was conducted towards the development of a passive wireless sensor for measurement of temperature in coal gasifiers and coal-fired boiler plants. Approaches investigated included metamaterial sensors based on guided mode resonance filters, and temperature-sensitive antennas that modulate the frequency of incident radio waves as they are re-radiated by the antenna. In the guided mode resonant filter metamaterial approach, temperature is encoded as changes in the sharpness of the filter response, which changes with temperature because the dielectric loss of the guided mode resonance filter is temperature-dependent. In the mechanically modulated antenna approach, the resonant frequency of a vibrating cantilever beam attached to the antenna changes with temperature. The vibration of the beam perturbs the electrical impedance of the antenna, so that incident radio waves are phase modulated at a frequency equal to the resonant frequency of the vibrating beam. Since the beam resonant frequency depends on temperature, a Doppler radar can be used to remotely measure the temperature of the antenna. Laboratory testing of the guided mode resonance filter failed to produce the spectral response predicted by simulations. It was concluded that the spectral response was dominated by spectral reflections of radio waves incident on the filter. Laboratory testing of the mechanically modulated antenna demonstrated that the device frequency shifted incident radio waves, and that the frequency of the re-radiated waves varied linearly with temperature. Radio wave propagation tests in the convection pass of a small research boiler plant identified a spectral window between 10 and 13 GHz for low loss propagation of radio waves in the interior of the boiler.

  17. Elastic properties of anorthite at high temperature and high pressure

    Science.gov (United States)

    Matsukage, K. N.; Nishihara, Y.; Noritake, F.; Tsujino, N.; Sakurai, M.; Higo, Y.; Kawamura, K.; Takahashi, E.

    2012-12-01

    To understand the elastic properties of subducted crustal minerals at P-T conditions of crust and upper most mantle, we performed in situ measurement of the elastic wave velocities of anorthite at temperatures up to 1100 oC at less than 2.0 GPa (in stability field) and up to 500 oC at 2.0-7.0 GPa. A fine grained polycrystalline anorthite was synthesised by using gas pressure apparatus installed at magma factory in Tokyo Institute of Technology. The quenched glass with anorthite composition was ground in ethanol and was loaded into a sealed Pt tube (3.0 mm inner diameter and 0.2 mm thickness) container. The sample was preheated at 900°C for 2 hours, and then keep at 1100°C for 20 hours at pressure of 0.3 GPa. The maximum grain size of the synthesized polycrystalline anorthite was about 15μm. The experiments were performed using the SPEED-1500 apparatus installed on beam line BL04B1 at synchrotron facility of SPring-8, Japan (Utsumi et al. 1998). The experimental design for in situ elastic wave velocities measurement at BL04B1 was presented by Higo et al. (2009). Pressure was generated by eight 26 mm tungsten carbide anvils with 11 mm truncated edge length. A Co-doped semi-sintered MgO octahedron with an 18 mm edge length was used as a pressure medium. The sample was enclosed in a BN sleeve container, and was placed in the central part (hot spot) of the furnace. Platinum foils (2.5 μm in thickness) were inserted at the both side of the sample for determination of sample length by using X-ray radiographic imaging techniques. An Al2O3 rod (5.3 mm in length and 2.0 mm in diameter) was used as buffer rod which transmit ultrasonic wave to the sample. Temperature was measured by a W97Re3-W75Re25 thermocouple. MgO was used as a pressure marker, and it was mixed with BN (MgO:BN = 1:1 by weight) to prevent grain growth at high temperatures. The ultrasonic signals were generated and received by 10oY-cut LiNbO3 transducer of 50 μm in thickness and 3.2 mm in diameter. We

  18. High temperature cement raw meal flowability

    DEFF Research Database (Denmark)

    Maarup, Claus; Hjuler, Klaus; Dam-Johansen, Kim

    2014-01-01

    The flowability of cement raw meal is investigated at temperatures up to 850°C in a specially designed monoaxial shear tester. Consolidation stresses of 0.94, 1.87 and 2.79kPa are applied. The results show that the flowability is reduced as temperature is increased above 550°C, indicated by incre...... by increasing unconfined yield strength and reduced flowability factors. Deviation and reproducibility are acceptable for all temperatures except for 850°C where belite formation and possibly calcination sinter the raw meal....

  19. Fusion reactors-high temperature electrolysis (HTE)

    Energy Technology Data Exchange (ETDEWEB)

    Fillo, J.A. (ed.)

    1978-01-01

    Results of a study to identify and develop a reference design for synfuel production based on fusion reactors are given. The most promising option for hydrogen production was high-temperature electrolysis (HTE). The main findings of this study are: 1. HTE has the highest potential efficiency for production of synfuels from fusion; a fusion to hydrogen energy efficiency of about 70% appears possible with 1800/sup 0/C HTE units and 60% power cycle efficiency; an efficiency of about 50% possible with 1400/sup 0/C HTE units and 40% power cycle efficiency. 2. Relative to thermochemical or direct decomposition methods HTE technology is in a more advanced state of development, 3. Thermochemical or direct decomposition methods must have lower unit process or capital costs if they are to be more attractive than HTE. 4. While design efforts are required, HTE units offer the potential to be quickly run in reverse as fuel cells to produce electricity for restart of Tokamaks and/or provide spinning reserve for a grid system. 5. Because of the short timescale of the study, no detailed economic evaluation could be carried out.A comparison of costs could be made by employing certain assumptions. For example, if the fusion reactor-electrolyzer capital installation is $400/(KW(T) ($1000/KW(E) equivalent), the H/sub 2/ energy production cost for a high efficiency (about 70 %) fusion-HTE system is on the same order of magnitude as a coal based SNG plant based on 1976 dollars. 6. The present reference design indicates that a 2000 MW(th) fusion reactor could produce as much at 364 x 10/sup 6/ scf/day of hydrogen which is equivalent in heating value to 20,000 barrels/day of gasoline. This would fuel about 500,000 autos based on average driving patterns. 7. A factor of three reduction in coal feed (tons/day) could be achieved for syngas production if hydrogen from a fusion-HTE system were used to gasify coal, as compared to a conventional syngas plant using coal-derived hydrogen.

  20. Fusion reactors-high temperature electrolysis (HTE)

    International Nuclear Information System (INIS)

    Results of a study to identify and develop a reference design for synfuel production based on fusion reactors are given. The most promising option for hydrogen production was high-temperature electrolysis (HTE). The main findings of this study are: 1. HTE has the highest potential efficiency for production of synfuels from fusion; a fusion to hydrogen energy efficiency of about 70% appears possible with 18000C HTE units and 60% power cycle efficiency; an efficiency of about 50% possible with 14000C HTE units and 40% power cycle efficiency. 2. Relative to thermochemical or direct decomposition methods HTE technology is in a more advanced state of development, 3. Thermochemical or direct decomposition methods must have lower unit process or capital costs if they are to be more attractive than HTE. 4. While design efforts are required, HTE units offer the potential to be quickly run in reverse as fuel cells to produce electricity for restart of Tokamaks and/or provide spinning reserve for a grid system. 5. Because of the short timescale of the study, no detailed economic evaluation could be carried out.A comparison of costs could be made by employing certain assumptions. For example, if the fusion reactor-electrolyzer capital installation is $400/(KW(T) [$1000/KW(E) equivalent], the H2 energy production cost for a high efficiency (about 70 %) fusion-HTE system is on the same order of magnitude as a coal based SNG plant based on 1976 dollars. 6. The present reference design indicates that a 2000 MW(th) fusion reactor could produce as much at 364 x 106 scf/day of hydrogen which is equivalent in heating value to 20,000 barrels/day of gasoline. This would fuel about 500,000 autos based on average driving patterns. 7. A factor of three reduction in coal feed (tons/day) could be achieved for syngas production if hydrogen from a fusion-HTE system were used to gasify coal, as compared to a conventional syngas plant using coal-derived hydrogen

  1. High Temperature Operational Experiences of Helium Experimental Loop

    International Nuclear Information System (INIS)

    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

  2. High-Temperature, High-Concentration Solar Thermoelectric Generators

    Science.gov (United States)

    Warren, Emily; Baranowski, Lauryn; Olsen, Michele; Ndione, Paul; Netter, Judy; Goodrich, Alan; Gray, Matthew; Parilla, Philip; Ginley, David; Toberer, Eric

    2014-03-01

    Solar thermoelectric generators (STEGs) powered with concentrated solar energy have potential for use as primary energy converters or as topping-cycles for more conventional concentrated solar power (CSP) technologies. Modeling based on current record modules from JPL suggests thermoelectric efficiencies of 18 % could be experimentally expected with a temperature gradient of 1000 - 100°C. Integrating these state-of-the-art TEGs with a concentrating solar receiver requires simultaneous optimization of optical, thermal, and thermoelectric systems. This talk will discuss the modeling, design, and experimental testing of STEG devices under concentrated sunlight. We have developed a model that combines thermal circuit modeling with optical ray tracing to design selective absorber coatings and cavities to minimize radiation losses from the system. We have fabricated selective absorber coatings and demonstrated that these selective absorber films can minimize blackbody radiation losses at high temperature and are stable after thermal cycling to 1000°C. On-sun testing of STEG devices and thermal simulators is ongoing and preliminary results will be discussed.

  3. High Temperature Acoustic Noise Reduction Materials Project

    Data.gov (United States)

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

  4. Extreme Environment High Temperature Communication Systems Project

    Data.gov (United States)

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

  5. Ultrasonic propagation in gases at high temperatures

    Science.gov (United States)

    Carey, C.; Carnevale, E. H.; Lynworth, L. C.; Uva, S.

    1970-01-01

    Ultrasonic pulse method /1 to 3 MHz/ measures both sound speed and absorption in monatomic and polyatomic gases in a temperature range of 300 to 20000 degrees K at atmospheric pressure. Helium, nitrogen, oxygen, and argon are investigated.

  6. Resilient thermal barrier for high temperatures

    Science.gov (United States)

    Frye, J. A.

    1977-01-01

    Abrasion-resistant thermal barrier, consisting of two layers of woven fabric or braided sleeving with bulk insulation sandwiched between, shows excellent resilience even after compression at temperatures above 980C.

  7. Inexpensive high-temperature solar collector

    Science.gov (United States)

    Dorman, J.; Lansing, F. L.

    1977-01-01

    Similar to flat-plate collector, concentrator uses water lenses to achieve temperatures near 200 degrees Centigrade. Lens assembly consists of parallel cylindrical lenses made of glass or plastic shells, reducing manufacturing costs and improving portability.

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

    Energy Technology Data Exchange (ETDEWEB)

    Bartalesi, Antonio; /Pisa U.

    2010-12-01

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

  9. [Genesis study of omphacite at high pressure and high temperature].

    Science.gov (United States)

    Xiao, Ben-Fu; Yi, Li; Wang, Duo-Jun; Xie, Chao; Tang, Xue-Wu; Liu, Lei; Cui, Yue-Ju

    2013-11-01

    The melting and recrystallizing experiments of alkali basalt powder and mixture of pure oxides mixed as stoichiometry were performed at 3 GPa and 1 200 degrees C. Electronic microprobe analysis and Raman spectra showed that the recrystallized products were omphacites, the FWHM (full width at half maximum) of the Raman peak was narrow and its shape was sharp, which is attributed to the stable Si-O tetrahedral structure and the high degree of order in omphacite. Based on the results of previous studies, the influencing factors of omphacite genesis and its primary magma were discussed. The results showed that the formation of omphacite could be affected by many factors, such as the composition of parent rocks, the concentration of fluid in the system and the conditions of pressure and temperature. This result could support some experimental evidences on the genesis studies of omphacite and eclogite.

  10. Polyakov loop at low and high temperatures

    OpenAIRE

    Megias, E.; Arriola, E. Ruiz; Salcedo, L. L.

    2005-01-01

    We describe how the coupling of the gluonic Polyakov loop to quarks solves different inconsistencies in the standard treatment of chiral quark models at finite temperature at the one quark loop level. Large gauge invariance is incorporated and an effective theory of quarks and Polyakov loops as basic degrees of freedom is generated. From this analysis we find a strong suppression of finite temperature effects in hadronic observables below the deconfinement phase transition triggered by approx...

  11. Voltage stabilizers for high temperature furnace

    International Nuclear Information System (INIS)

    The stabilization of furnace temperatures in the range 1500-2500 C has been achieved by controlling the effective (rms) value of the supply voltage of the heating element. Temperature variations are less than, or equal to, one degree C in the whole working range of the furnace. Two types of set-ups have been developed: one is static, the other takes use of a servo-motor. (author)

  12. HIGH TEMPERATURE MATERIALS AND STRENGTH STUDY IN CHINA

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    In the past half century China has developed and formed her own system of high temperature materials for power, automobile and aero-engine industries in the temperature range from 550 ℃ to 1 100 ℃. These high temperature materials include heat-resisting steels, iron-base, nickel-iron-base and nickel-base superalloys. Some achievements in high temperature strength study, new technologies and new alloy development are also discussed.

  13. Rock bed heat accumulators. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Riaz, M.

    1977-12-01

    The principal objectives of the research program on rock bed heat accumulators (or RBHA) are: (1) to investigate the technical and economic feasibility of storing large amounts of thermal energy (in the tens of MWt range) at high temperature (up to 500/sup 0/C) over extended periods of time (up to 6 months) using native earth or rock materials; (2) to conduct studies to establish the performance characteristics of large rock bed heat accumulators at various power and temperature levels compatible with thermal conversion systems; and (3) to assess the materials and environmental problems associated with the operation of such large heat accumulators. Results of the study indicate that rock bed heat accumulators for seasonal storage are both technically and economically feasible, and hence could be exploited in various applications in which storage plays an essential role such as solar power and total energy systems, district and cogeneration heating systems.

  14. Validation of SCALE for High Temperature Gas-Cooled Reactors Analysis

    Energy Technology Data Exchange (ETDEWEB)

    Ilas, Germina [ORNL; Ilas, Dan [ORNL; Kelly, Ryan P [ORNL; Sunny, Eva E [ORNL

    2012-08-01

    This report documents verification and validation studies carried out to assess the performance of the SCALE code system methods and nuclear data for modeling and analysis of High Temperature Gas-Cooled Reactor (HTGR) configurations. Validation data were available from the International Handbook of Evaluated Reactor Physics Benchmark Experiments (IRPhE Handbook), prepared by the International Reactor Physics Experiment Evaluation Project, for two different HTGR designs: prismatic and pebble bed. SCALE models have been developed for HTTR, a prismatic fuel design reactor operated in Japan and HTR-10, a pebble bed reactor operated in China. The models were based on benchmark specifications included in the 2009, 2010, and 2011 releases of the IRPhE Handbook. SCALE models for the HTR-PROTEUS pebble bed configuration at the PROTEUS critical facility in Switzerland have also been developed, based on benchmark specifications included in a 2009 IRPhE draft benchmark. The development of the SCALE models has involved a series of investigations to identify particular issues associated with modeling the physics of HTGRs and to understand and quantify the effect of particular modeling assumptions on calculation-to-experiment comparisons.

  15. NOVEL REFRACTORY MATERIALS FOR HIGH ALKALI, HIGH TEMPERATURE ENVIRONMENTS

    Energy Technology Data Exchange (ETDEWEB)

    Hemrick, James Gordon [ORNL; Smith, Jeffrey D [ORNL; O' Hara, Kelley [University of Missouri, Rolla; Rodrigues-Schroer, Angela [Minteq International, Inc.; Colavito, [Minteq International, Inc.

    2012-08-01

    A project was led by Oak Ridge National Laboratory (ORNL) in collaboration with a research team comprised of the academic institution Missouri University of Science and Technology (MS&T), and the industrial company MINTEQ International, Inc. (MINTEQ), along with representatives from the aluminum, chemical, glass, and forest products industries. The project was to address the need for new innovative refractory compositions by developing a family of novel MgO-Al 2O3, MgAl2O4, or other similar spinel structured or alumina-based unshaped refractory compositions (castables, gunnables, shotcretes, etc.) utilizing new aggregate materials, bond systems, protective coatings, and phase formation techniques (in-situ phase formation, altered conversion temperatures, accelerated reactions, etc). This family of refractory compositions would then be tailored for use in high-temperature, high-alkaline industrial environments like those found in the aluminum, chemical, forest products, glass, and steel industries. Both practical refractory development experience and computer modeling techniques were used to aid in the design of this new family of materials. The newly developed materials were expected to offer alternative material choices for high-temperature, high-alkali environments that were capable of operating at higher temperatures (goal of increasing operating temperature by 100-200oC depending on process) or for longer periods of time (goal of twice the life span of current materials or next process determined service increment). This would lead to less process down time, greater energy efficiency for associated manufacturing processes (more heat kept in process), and materials that could be installed/repaired in a more efficient manner. The overall project goal was a 5% improvement in energy efficiency (brought about through a 20% improvement in thermal efficiency) resulting in a savings of 3.7 TBtu/yr (7.2 billion ft3 natural gas) by the year 2030. Additionally, new

  16. Oxide films in high temperature aqueous environments

    International Nuclear Information System (INIS)

    chemistries in Finnish power plants. To achieve this, the focus of this project is on understanding the mechanism of the incorporation of radioactive species into the different layers of the oxide film, as well as the transport phenomena contributing to stress corrosion cracking and other corrosion phenomena. This requires modelling the electrochemical behaviour and electrochemical and electric properties of oxide films formed on iron- and nickel-based alloys in relevant conditions. The project is divided into four sub-projects as follows: Behaviour of oxide films in plant conditions; Oxide films in simulated plant conditions; Modelling the processes in oxide films on metal surfaces; and Development of electrochemical measurements techniques for high-temperature measurements. (author)

  17. Thermodynamic evaluation of supercritical oxy-type power plant with high-temperature three-end membrane for air separation

    Directory of Open Access Journals (Sweden)

    Kotowicz Janusz

    2014-09-01

    Full Text Available Among the technologies which allow to reduce greenhouse gas emissions, mainly of carbon dioxide, special attention deserves the idea of ‘zero-emission’ technology based on boilers working in oxy-combustion technology. In the paper a thermodynamic analysis of supercritical power plant fed by lignite was made. Power plant consists of: 600 MW steam power unit with live steam parameters of 650 °C/30 MPa and reheated steam parameters of 670 °C/6 MPa; circulating fluidized bed boiler working in oxy-combustion technology; air separation unit and installation of the carbon dioxide compression. Air separation unit is based on high temperature membrane working in three-end technology. Models of steam cycle, circulation fluidized bed boiler, air separation unit and carbon capture installation were made using commercial software. After integration of these models the net electricity generation efficiency as a function of the degree of oxygen recovery in high temperature membrane was analyzed.

  18. Dielectric constant of water at very high temperature and pressure

    OpenAIRE

    Pitzer, Kenneth S.

    1983-01-01

    Pertinent statistical mechanical theory is combined with the available measurements of the dielectric constant of water at high temperature and pressure to predict that property at still higher temperature. The dielectric constant is needed in connection with studies of electrolytes such as NaCl/H2O at very high temperature.

  19. 46 CFR 56.60-5 - Steel (High temperature applications).

    Science.gov (United States)

    2010-10-01

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

  20. Fiber Optical Sensor for High Temperatures

    Directory of Open Access Journals (Sweden)

    Vladimir Vasinek

    2010-01-01

    Full Text Available The fiber optic sensors are used in various industries. Advantages of optical sensors are based on the benefits of fiber and partially profit at their technological advances. The fiber optic temperature sensors are based on more than one way of scanning, all reach the upper scanning limit of about 600 °C. This article aims to introduce the principle of the sensor based on black body radiation. This type of sensor is difficult to specify precisely, it can not be easily classified into groups of intensity sensors or radiation sensors. At lower temperatures, it could be classified into intensity sensors, but at higher temperatures occurs to its own radiation of photons inside the fiber.