WorldWideScience

Sample records for internal heating rates

  1. Economic analysis of solar industrial process heat systems: A methodology to determine annual required revenue and internal rate of return

    Science.gov (United States)

    Dickinson, W. C.; Brown, K. C.

    1981-08-01

    An economic evaluation of solar industrial process heat systems, is developed to determine the annual required revenue and the internal rate of return. First, a format is provided to estimate the solar system's installed cost, annual operating and maintenance expenses, and net annual solar energy delivered to the industrial process. The annual required revenue and the price of solar is calculated. The economic attractiveness of the potential solar investment can be determined by comparing the price of solar energy with the price of fossilfuel, both expressed in levelized terms. This requires calcuation of the internal rate of return on the solar investment or, in certain cases, the growth rate of return.

  2. VII international district heating conference

    International Nuclear Information System (INIS)

    1988-01-01

    The proceedings of the 7th International District Heating Conference contain the full texts of the 89 presented papers of which 11 fall under the INIS Subject Scope. The conference met in seven sessions and dealt with the following problem areas: design and optimization of systems of district heating, integration of the power system and the district heating systems, cooperation of nuclear and fossil burning sources in district heating systems, the use of specific nuclear power plants for heating purposes, questions of the control of systems of district heating, the development of components of heating networks, the reliability and design of heat supply pipes. (Z.M.)

  3. Heat transfer from internally heated hemispherical pools

    International Nuclear Information System (INIS)

    Gabor, J.D.; Ellsion, P.G.; Cassulo, J.C.

    1980-01-01

    Experiments were conducted on heat transfer from internally heated ZnSO 4 -H 2 O pools to the walls of hemispherical containers. This experimental technique provides data for a heat transfer system that has to date been only theoretically treated. Three different sizes of copper hemispherical containers were used: 240, 280, 320 mm in diameter. The pool container served both as a heat transfer surface and as an electrode. The opposing electrode was a copper disk, 50 mm in diameter located at the top of the pool in the center. The top surface of the pool was open to the atmosphere

  4. Internally Heated Screw Pyrolysis Reactor (IHSPR) heat transfer performance study

    Science.gov (United States)

    Teo, S. H.; Gan, H. L.; Alias, A.; Gan, L. M.

    2018-04-01

    1.5 billion end-of-life tyres (ELT) were discarded globally each year and pyrolysis is considered the best solution to convert the ELT into valuable high energy-density products. Among all pyrolysis technologies, screw reactor is favourable. However, conventional screw reactor risks plugging issue due to its lacklustre heat transfer performance. An internally heated screw pyrolysis reactor (IHSPR) was developed by local renewable energy industry, which serves as the research subject for heat transfer performance study of this particular paper. Zero-load heating test (ZLHT) was first carried out to obtain the operational parameters of the reactor, followed by the one dimensional steady-state heat transfer analysis carried out using SolidWorks Flow Simulation 2016. Experiments with feed rate manipulations and pyrolysis products analyses were conducted last to conclude the study.

  5. Postaccident heat removal. II. Heat transfer from an internally heated liquid to a melting solid

    International Nuclear Information System (INIS)

    Faw, R.E.; Baker, L. Jr.

    1976-01-01

    Microwave heating has been used in studies of heat transfer from a horizontal layer of internally heated liquid to a melting solid. Experiments were designed to simulate heat transfer and meltthrough processes of importance in the analysis of postaccident heat removal capabilities of nuclear reactors. Glycerin, heated by 2.45-GHz microwave radiation, was used to simulate molten fuel. Paraffin wax was used to simulate a melting barrier confining the fuel. Experimentally measured heat fluxes and melting rates were consistent with a model based on downward heat transfer by conduction through a stagnant liquid layer and upward heat transfer augmented by natural convection. Melting and displacement of the barrier material occurred by upward-moving droplets randomly distributed across the melting surface. Results indicated that the melting and displacement process had no effect on the heat transfer process

  6. Mixing in heterogeneous internally-heated convection

    Science.gov (United States)

    Limare, A.; Kaminski, E. C.; Jaupart, C. P.; Farnetani, C. G.; Fourel, L.; Froment, M.

    2017-12-01

    Past laboratory experiments of thermo chemical convection have dealt with systems involving fluids with different intrinsic densities and viscosities in a Rayleigh-Bénard setup. Although these experiments have greatly improved our understanding of the Earth's mantle dynamics, they neglect a fundamental component of planetary convection: internal heat sources. We have developed a microwave-based method in order to study convection and mixing in systems involving two layers of fluid with different densities, viscosities, and internal heat production rates. Our innovative laboratory experiments are appropriate for the early Earth, when the lowermost mantle was likely enriched in incompatible and heat producing elements and when the heat flux from the core probably accounted for a small fraction of the mantle heat budget. They are also relevant to the present-day mantle if one considers that radioactive decay and secular cooling contribute both to internal heating. Our goal is to quantify how two fluid layers mix, which is still very difficult to resolve accurately in 3-D numerical calculations. Viscosities and microwave absorptions are tuned to achieve high values of the Rayleigh-Roberts and Prandtl numbers relevant for planetary convection. We start from a stably stratified system where the lower layer has higher internal heat production and density than the upper layer. Due to mixing, the amount of enriched material gradually decreases to zero over a finite time called the lifetime. Based on more than 30 experiments, we have derived a scaling law that relates the lifetime of an enriched reservoir to the layer thickness ratio, a, to the density and viscosity contrasts between the two layers, and to their two different internal heating rates in the form of an enrichment factor beta=1+2*a*H1/H, where H1 is the heating rate of the lower fluid and H is the average heating rate. We find that the lifetime of the lower enriched reservoir varies as beta**(-7/3) in the low

  7. Cyclotron heating rate in a parabolic mirror

    International Nuclear Information System (INIS)

    Smith, P.K.

    1984-01-01

    Cyclotron resonance heating rates are found for a parabolic magnetic mirror. The equation of motion for perpendicular velocity is solved, including the radial magnetic field terms neglected in earlier papers. The expression for heating rate involves an infinite series of Anger's and Weber's functions, compared with a single term of the unrevised expression. The new results show an increase of heating rate compared with previous results. A simple expression is given for the ratio of the heating rates. (author)

  8. Effect of high heating rate on thermal decomposition behaviour of ...

    Indian Academy of Sciences (India)

    Effect of high heating rate on thermal decomposition behaviour of titanium hydride ... hydride powder, while switching it from internal diffusion to chemical reaction. ... TiH phase and oxides form on the powder surface, controlling the process.

  9. Investigation of internally finned LED heat sinks

    Science.gov (United States)

    Li, Bin; Xiong, Lun; Lai, Chuan; Tang, Yumei

    2018-03-01

    A novel heat sink is proposed, which is composed of a perforated cylinder and internally arranged fins. Numerical studies are performed on the natural convection heat transfer from internally finned heat sinks; experimental studies are carried out to validate the numerical results. To compare the thermal performances of internally finned heat sinks and externally finned heat sinks, the effects of the overall diameter, overall height, and installation direction on maximum temperature, air flow and heat transfer coefficient are investigated. The results demonstrate that internally finned heat sinks show better thermal performance than externally finned heat sinks; the maximum temperature of internally finned heat sinks decreases by up to 20% compared with the externally finned heat sinks. The existence of a perforated cylinder and the installation direction of the heat sink affect the thermal performance significantly; it is shown that the heat transfer coefficient of the heat sink with the perforated cylinder is improved greater than that with the imperforated cylinder by up to 34%, while reducing the mass of the heat sink by up to 13%. Project supported by the Scientific Research Fund of Sichuan Provincial Education Department (No. 18ZB0516) and the Sichuan University of Arts and Science (No. 2016KZ009Y).

  10. Heat transfer from internally-heated molten UO2 pools

    International Nuclear Information System (INIS)

    Stein, R.P.; Baker, L. Jr.; Gunther, W.H.; Cook, C.

    1978-01-01

    Experimental measurements of heat transfer from internally heated pools of molten UO 2 have been obtained for two cell sizes: 10 cm x 10 cm and 20 cm x 20 cm. The experiments with the large cell have supported a previous conclusion from early small data that the measured downward heat fluxes are higher than would be expected on the basis of considerations of thermal convection. A convective model underpredicts the downward heat fluxes by a factor of 2.5 to 4.5 for all but one early experiment. Arbitrary assumptions of increased thermal conductivity do not account for the discrepancy. A single model based on internal thermal radiation heat transfer is able to account for the high values. The model uses the optically thick Rosseland approximation. Because of this, it is tentatively concluded that thermal radiation plays a dominant role in controlling the heat transfer from internally heated molted fuel

  11. Thermal electron heating rate: a derivation

    International Nuclear Information System (INIS)

    Hoegy, W.R.

    1983-11-01

    The thermal electron heating rate is an important heat source term in the ionospheric electron energy balance equation, representing heating by photoelectrons or by precipitating higher energy electrons. A formula for the thermal electron heating rate is derived from the kinetic equation using the electron-electron collision operator as given by the unified theory of Kihara and Aono. This collision operator includes collective interactions to produce a finite collision operator with an exact Coulomb logarithm term. The derived heating rate O(e) is the sum of three terms, O(e) O(p) + S + O(int), which are respectively: (1) primary electron production term giving the heating from newly created electrons that have not yet suffered collisions with the ambient electrons, (2) a heating term evaluated on the energy surface m(e)/2 E(T) at the transition between Maxwellian and tail electrons at E(T), and (3) the integral term representing heating of Maxwellian electrons by energetic tail electrons at energies ET. Published ionospheric electron temperature studies used only the integral term O(int) with differing lower integration limits. Use of the incomplete heating rate could lead to erroneous conclusions regarding electron heat balance, since O(e) is greater than O(int) by as much as a factor of two

  12. Production of molten UO2 pools by internal heating: apparatus and preliminary experimental heat transfer results

    International Nuclear Information System (INIS)

    Chasanov, M.G.; Gunther, W.H.; Baker, L. Jr.

    1977-01-01

    The capability for removal of heat from a pool of molten fuel under postaccident conditions is an important consideration in liquid-metal fast breeder reactor safety analysis. No experimental data for pool heat transfer from molten UO 2 under conditions simulating internal heat generation by fission product decay have been reported previously in the literature. An apparatus to provide such data was developed and used to investigate heat transfer from pools containing up to 7.5 kg of UO 2 ; the internal heat generation rates and pool depths attained cover most of the ranges of interest for postaccident heat removal analysis. It was also observed in these studies that the presence of simulated fission products corresponding to approximately 150,000 kW-day/kg burnup had no significant effect on the observed heat transfer

  13. The log mean heat transfer rate method of heat exchanger considering the influence of heat radiation

    International Nuclear Information System (INIS)

    Wong, K.-L.; Ke, M.-T.; Ku, S.-S.

    2009-01-01

    The log mean temperature difference (LMTD) method is conventionally used to calculate the total heat transfer rate of heat exchangers. Because the heat radiation equation contains the 4th order exponential of temperature which is very complicate in calculations, thus LMTD method neglects the influence of heat radiation. From the recent investigation of a circular duct in some practical situations, it is found that even in the situation of the temperature difference between outer duct surface and surrounding is low to 1 deg. C, the heat radiation effect can not be ignored in the situations of lower ambient convective heat coefficient and greater surface emissivities. In this investigation, the log mean heat transfer rate (LMHTR) method which considering the influence of heat radiation, is developed to calculate the total heat transfer rate of heat exchangers.

  14. MATHEMATICAL MODELING OF HEATING RATE PRODUCT AT HIGH HEAT TREATMENT

    Directory of Open Access Journals (Sweden)

    M. M. Akhmedova

    2014-01-01

    Full Text Available Methods of computing and mathematical modeling are all widely used in the study of various heat exchange processes that provide the ability to study the dynamics of the processes, as well as to conduct a reasonable search for the optimal technological parameters of heat treatment.This work is devoted to the identification of correlations among the factors that have the greatest effect on the rate of heating of the product at hightemperature heat sterilization in a stream of hot air, which are chosen as the temperature difference (between the most and least warming up points and speed cans during heat sterilization.As a result of the experimental data warming of the central and peripheral layers compote of apples in a 3 liter pot at high-temperature heat treatment in a stream of hot air obtained by the regression equation in the form of a seconddegree polynomial, taking into account the effects of pair interaction of these parameters. 

  15. Corrosion Rate Monitoring in District Heating Systems

    DEFF Research Database (Denmark)

    Hilbert, Lisbeth Rischel; Nielsen, Lars Vendelbo; Andersen, A.

    2005-01-01

    be applicable, and if on-line monitoring could improve the quality control. Water quality monitoring was applied as well as corrosion rate monitoring with linear polarization resistance (LPR), electrochemical impedance spectroscopy (EIS), electrical resistance (ER) technique, mass loss and a crevice corrosion......Quality control in district heating systems to keep uniform corrosion rates low and localized corrosion minimal is based on water quality control. Side-stream units equipped with carbon steel probes for online monitoring were mounted in district heating plants to investigate which techniques would...... cell for localized corrosion risk estimation. Important variations in corrosion rate due to changes in make-up water quality were detected with the continuous monitoring provided by ER and crevice cell, while LPR gave unreliable corrosion rates. The acquisition time of two-three days for EIS...

  16. Steady, three-dimensional, internally heated convection

    International Nuclear Information System (INIS)

    Schubert, G.; Glatzmaier, G.A.; Travis, B.

    1993-01-01

    Numerical calculations have been carried out of steady, symmetric, three-dimensional modes of convection in internally heated, infinite Prandtl number, Boussinesq fluids at a Rayleigh number of 1.4x10 4 in a spherical shell with inner/outer radius of 0.55 and in a 3x3x1 rectangular box. Multiple patterns of convection occur in both geometries. In the Cartesian geometry the patterns are dominated by cylindrical cold downflows and a broad hot upwelling. In the spherical geometry the patterns consist of cylindrical cold downwellings centered either at the vertices of a tetrahedron or the centers of the faces of a cube. The cold downflow cylinders are immersed in a background of upwelling within which there are cylindrical hot concentrations (plumes) and hot halos around the downflows. The forced hot upflow return plumes of internally heated spherical convection are fundamentally different from the buoyancy-driven plumes of heated from below convection

  17. Heat transfer of liquid-metal magnetohydrodynamic flow with internal heat generation

    International Nuclear Information System (INIS)

    Kumamaru, Hiroshige; Kurita, Kazuhisa; Kodama, Satoshi

    2000-01-01

    Numerical calculations on heat transfer of a magnetohydrodynamic (MHD) flow with internal heat generation in a rectangular channel have been performed for the cases of very-large Hartmann numbers, finite wall conductivities and small aspect ratio (i.e. small length ratios of the channel side perpendicular to the applied magnetic field and the side parallel to the field), simulating typical conditions for a fusion-reactor blanket. The Nusselt numbers of the MHD flow in rectangular channels with aspect ratios of 1/10 to 1/40 for Hartmann numbers of ∼5 x 10 5 become ∼10 times higher than those for the corresponding flow under no magnetic field. The Nusselt number becomes higher as the internal heat generation rate increases as far as the heat generation rates in a fusion reactor blanket are considered. (author)

  18. Rapid heating tensile tests of high-energy-rate-forged 316L stainless steel containing internal helium from radioactive decay of absorbed tritium

    International Nuclear Information System (INIS)

    Mosley, W.C.

    1990-01-01

    316L stainless steel is a candidate material for construction of equipment that will be exposed to tritium. This austenitic stainless steel is frequently used in the high-energy-rate-forged (HERF) metallurgical condition to take advantage of increased strength produced by cold work introduced by this process. Proper design of tritium-handling equipment will require an understanding of how helium-3, the product of radioactive decay of tritium, affects mechanical properties. This report describes results of elevated-temperature tensile testing of HERF 316L stainless steel specimens containing helium concentrations of 171 (calculated) atomic parts per million (appm). Results are compared with those reported previously for specimens containing 0 and 94 (measured) appm helium

  19. Heating and cooling rates and their effects upon heart rate in the ...

    African Journals Online (AJOL)

    The heating and cooling rates of adult Chersina angulata were investigated to ascertain whether these tortoises can physiologically alter their rates of heat exchange. In addition, heart rates were recorded to provide an insight into the control of heat exchange. C. angulata heats significantly faster than it cools. Heart rates ...

  20. House-internal heating systems; Husinterna vaermesystem

    Energy Technology Data Exchange (ETDEWEB)

    Johansson, Per-Olof; Wollerstrand, Janusz [Lund Univ. (Sweden). Dept. of Heat and Power Engineering

    2005-07-01

    In this report the placement of the circulation-pump in of waterborne radiator systems, as well as their filling and deairation are investigated. The study was done by literature studies and interviews with consultants and companies active on the HVAC-market. It was concluded that different placements of the pump in relationship to the heat exchanger exist, and the arguments for the choice of placement are varying. The main explanation of the choice of placement is that it is based on experience/or by practical reasons. The most important factor influencing the placement of the pump found, was how the pump is situated in relation to the expansion-tank. To maintain pressure in the whole system the expansion-tank should be placed on the suction side of the pump without any intermediate pressure-dropping devices in between. This placement ensures overpressure in the whole radiator-system and reduces the risk of unwanted leak in of air. To avoid cavitation sufficient static pressure on the suction side of the pump is necessary. The pressure increases with the temperature, which must be taken into consideration if the pump is placed on the warm side of the heat-exchanger. From this point of view a placement in the return-pipe from the radiator-system is to be preferred. Before advices for HVAC-branch regarding placement of the circulation-pump in the heating systems can be implemented, it is of big importance to analyse and clearly specify the advantages and disadvantages of a certain placement of the pump. There is a need of directions to get house-internal systems to operate properly together with district heating system. This is especially important when older heating systems with burners and shunt valves are being connected. Filling and deairation of the radiator system is of great importance for the function of the system. A radiator-system with significant level of air remains is difficult to adjust and will not work properly. Air in the radiators leads to

  1. Relationship between the shear viscosity and heating rate in metallic glasses below the glass transition

    International Nuclear Information System (INIS)

    Khonik, Vitaly A.; Kobelev, N. P.

    2008-01-01

    It has been shown that first-order irreversible structural relaxation with distributed activation energies must lead to a linear decrease of the logarithm of Newtonian shear viscosity with the logarithm of heating rate upon linear heating of glass. Such a behavior is indeed observed in the experiments on metallic glasses. Structural relaxation-induced viscous flow leads to infra-low-frequency Maxwell viscoelastic internal friction, which is predicted to increase with the heating rate

  2. Heat release rate of wood-plastic composites

    Science.gov (United States)

    N. M. Stark; R. H. White; C. M. Clemons

    1997-01-01

    Wood-plastic composites are becoming more important as a material that fulfills recycling needs. In this study, fire performance tests were conducted on several compositions of wood and plastic materials using the Ohio State University rate of heat release apparatus. Test results included five-minute average heat release rate in kW/m2 (HRR avg) and maximum heat release...

  3. The optimization of longitudinal convective fins with internal heat generation

    International Nuclear Information System (INIS)

    Razelos, P.

    1979-01-01

    The solution of the optimization problem for longitudinal convective fins of constant thickness, triangular or parabolic profile, and uniform internal heat generation, is presented. The cases considered are those of a given heat generation density, total heat generation and heat generation per unit width of the fin, when either the heat dissipation or the width of the fin is prescribed. The results are set forth in a nondimensional form, which are presented graphically. The effect of the fin's thermal conductivity upon the optimum dimensions is discussed, and limiting values for the heat generation and the heat dissipation, which may be imposed on the fin for a feasible optimization, are also obtained. (Auth.)

  4. Heat exchangers selection, rating, and thermal design

    CERN Document Server

    Kakaç, Sadik; Pramuanjaroenkij, Anchasa

    2012-01-01

    Praise for the Bestselling Second EditionThe first edition of this work gathered in one place the essence of important information formerly scattered throughout the literature. The second edition adds the following new information: introductory material on heat transfer enhancement; an application of the Bell-Delaware method; new correlation for calculating heat transfer and friction coefficients for chevron-type plates; revision of many of the solved examples and the addition of several new ones.-MEMagazine

  5. High Heating Rates Affect Greatly the Inactivation Rate of Escherichia coli

    Science.gov (United States)

    Huertas, Juan-Pablo; Aznar, Arantxa; Esnoz, Arturo; Fernández, Pablo S.; Iguaz, Asunción; Periago, Paula M.; Palop, Alfredo

    2016-01-01

    Heat resistance of microorganisms can be affected by different influencing factors. Although, the effect of heating rates has been scarcely explored by the scientific community, recent researches have unraveled its important effect on the thermal resistance of different species of vegetative bacteria. Typically heating rates described in the literature ranged from 1 to 20°C/min but the impact of much higher heating rates is unclear. The aim of this research was to explore the effect of different heating rates, such as those currently achieved in the heat exchangers used in the food industry, on the heat resistance of Escherichia coli. A pilot plant tubular heat exchanger and a thermoresistometer Mastia were used for this purpose. Results showed that fast heating rates had a deep impact on the thermal resistance of E. coli. Heating rates between 20 and 50°C/min were achieved in the heat exchanger, which were much slower than those around 20°C/s achieved in the thermoresistometer. In all cases, these high heating rates led to higher inactivation than expected: in the heat exchanger, for all the experiments performed, when the observed inactivation had reached about seven log cycles, the predictions estimated about 1 log cycle of inactivation; in the thermoresistometer these differences between observed and predicted values were even more than 10 times higher, from 4.07 log cycles observed to 0.34 predicted at a flow rate of 70 mL/min and a maximum heating rate of 14.7°C/s. A quantification of the impact of the heating rates on the level of inactivation achieved was established. These results point out the important effect that the heating rate has on the thermal resistance of E. coli, with high heating rates resulting in an additional sensitization to heat and therefore an effective food safety strategy in terms of food processing. PMID:27563300

  6. Thermal resistance of a convectively cooled plate with applied heat flux and variable internal heat generation

    International Nuclear Information System (INIS)

    Venkataraman, N.S.; Cardoso, H.P.; Oliveira Filho, O.B. de

    1981-01-01

    The conductive heat transfer in a rectangular plate with nonuniform internal heat generation, with one end convectively cooled and a part of the opposite end subjected to external heat flux is considered. The remaining part of this end as well as the other two sides are thermally insulated. The governing differential equation is solved by a finite difference scheme. The variation of the thermal resistance with Biot modulus, the plate geometry, the internal heat generation parameter and the type of profile of internal heat generation is discussed. (author) [pt

  7. Heat transfer rate within non-spherical thick grains

    Directory of Open Access Journals (Sweden)

    Huchet Florian

    2017-01-01

    Full Text Available The prediction of the internal heat conduction into non-spherical thick grains constitutes a significant issue for physical modeling of a large variety of application involving convective exchanges between fluid and grains. In that context, the present paper deals with heat rate measurements of various sizes of particles, the thermal sensors being located at the interface fluid/grain and into the granular materials. Their shape is designed as cuboid in order to control the surface exchanges. In enclosed coneshaped apparatus, a sharp temperature gradient is ensured from a hot source releasing the air stream temperature equal to about 400°C. Two orientations of grain related to the air stream are considered: diagonally and straight arrangements. The thermal diffusivity of the grains and the Biot numbers are estimated from an analytical solution established for slab. The thermal kinetics evolution is correlated to the sample granular mass and its orientation dependency is demonstrated. Consequently, a generalized scaling law is proposed which is funded from the effective area of the heat transfer at the grain-scale, the dimensionless time being defined from the calculated diffusional coefficients.

  8. Heat transfer rate within non-spherical thick grains

    Science.gov (United States)

    Huchet, Florian; Richard, Patrick; Joniot, Jules; Le Guen, Laurédan

    2017-06-01

    The prediction of the internal heat conduction into non-spherical thick grains constitutes a significant issue for physical modeling of a large variety of application involving convective exchanges between fluid and grains. In that context, the present paper deals with heat rate measurements of various sizes of particles, the thermal sensors being located at the interface fluid/grain and into the granular materials. Their shape is designed as cuboid in order to control the surface exchanges. In enclosed coneshaped apparatus, a sharp temperature gradient is ensured from a hot source releasing the air stream temperature equal to about 400°C. Two orientations of grain related to the air stream are considered: diagonally and straight arrangements. The thermal diffusivity of the grains and the Biot numbers are estimated from an analytical solution established for slab. The thermal kinetics evolution is correlated to the sample granular mass and its orientation dependency is demonstrated. Consequently, a generalized scaling law is proposed which is funded from the effective area of the heat transfer at the grain-scale, the dimensionless time being defined from the calculated diffusional coefficients.

  9. Transition to chaos in a square enclosure containing internal heat sources

    Energy Technology Data Exchange (ETDEWEB)

    Baytas, A.C. [Institute For Nuclear Energy, Istanbul (Turkey)

    1995-09-01

    A numerical investigation is performed to study the transition from steady to chaotic flow of a fluid confined in a two-dimensional square cavity. The cavity has rigid walls of constant temperature containing uniformly distributed internal heat source. Effects of the Rayleigh number of flow and heat transfer rates are studied. In addition to, same problem is solved for sinusoidally changing internal heat source to show its effect on the flow model and heat transfer of the enclosures. Details of oscillatory solutions and flow bifurcations are presented.

  10. Analysis of the internal heat losses in a thermoelectric generator

    DEFF Research Database (Denmark)

    Bjørk, Rasmus; Christensen, Dennis Valbjørn; Eriksen, Dan

    2014-01-01

    and radiative heat losses, including surface to surface radiation. For radiative heat losses it is shown that for the temperatures considered here, surface to ambient radiation is a good approximation of the heat loss. For conductive heat transfer the module efficiency is shown to be comparable to the case...... of radiative losses. Finally, heat losses due to internal natural convection in the module is shown to be negligible for the millimetre sized modules considered here. The combined case of radiative and conductive heat transfer resulted in the lowest efficiency. The optimized load resistance is found...... to decrease for increased heat loss. The leg dimensions are varied for all heat losses cases and it is shown that the ideal way to construct a TEG module with minimal heat losses and maximum efficiency is to either use a good insulating material between the legs or evacuate the module completely, and use...

  11. Heat transfer in window frames with internal cavities

    Energy Technology Data Exchange (ETDEWEB)

    Gustavsen, Arild

    2001-07-01

    rates. From the results it appears that the thermal transmittance of a four-sided section can be found by calculating the average of the thermal transmittance of the respective single horizontal and vertical sections. In addition, it was found that two-dimensional conduction heat transfer simulation software agrees well with three-dimensional CFD simulations if the natural convection correlations used for the internal cavities are correct. Numerical simulations were done with natural convection in three-dimensional cavities with a high vertical aspect ratio and a low horizontal aspect ratio. The cavities studied had vertical aspect ratios of 20, 40, and 80 and horizontal aspect ratios ranging from 0.2 to 5. It was shown that three-dimensional cavities with a horizontal aspect ratio larger than five can be considered to be a two-dimensional cavity to within 4 % when considering heat transfer rates. Nusselt number correlations for the different horizontal aspect ratios are presented for cavities with vertical aspect ratios of 20 and 40. Complex multicellular flow was studied for the case where the vertical and horizontal aspect ratios were 40 and 2, respectively. Experimental studies included the normal spectral and total emissivity of specimens from six meter long untreated and anodized aluminum profiles. Specimens facing the internal cavities (thermal break cavity and all aluminum cavity) were measured. Some masking tapes often used in hot box experiments were also measured. The normal total emissivity was found to be is fairly constant (between 0.834 and 0.856) for exterior parts of the anodized profile and for surfaces facing the thermal break cavity. The normal total emissivity of the all-aluminum internal cavities was found to vary between 0.055 and 0.82. The experiments were performed with a Fourier transform infrared spectrometer in the wavelength interval from 4.5 to 40 mm. (author)

  12. International symposium on transient convective heat transfer: book of abstracts

    International Nuclear Information System (INIS)

    1996-01-01

    The international symposium on convective heat transfer was held on 19-23 August 1996, in Cesme, Izmir, Turkey. The spesialists discussed forced convection, heat exchangers, free convection and multiphase media and phase change at the meeting. Almost 53 papers were presented in the meeting

  13. Molecular investigations on grain filling rate under terminal heat ...

    African Journals Online (AJOL)

    Grain yield under post anthesis high temperature stress is largely influenced by grain filling rate (GFR). To investigate molecular basis of this trait, a set of 111 recombinant inbred lines (RILs) derived from Raj 4014, a heat sensitive genotype and WH 730, heat tolerant cultivar was phenotyped during 2009-2010 and ...

  14. Studies on Microwave Heated Drying-rate Equations of Foods

    OpenAIRE

    呂, 聯通; 久保田, 清; 鈴木, 寛一; 岡崎, 尚; 山下, 洋右

    1990-01-01

    In order to design various microwave heated drying apparatuses, we must take drying-rate equations which are based on simple drying-rate models. In a previous paper (KUBOTA, et al., 1990), we have studied a convenient microwave heated drying instrument, and studied the simple drying-rate equations of potato and so on by using the simple empirical rate equations that have been reported in previous papers (KUBOTA, 1979-1, 1979-2). In this paper, we studied the microwave drying rate of the const...

  15. Effect of high heating rate on thermal decomposition behaviour of ...

    Indian Academy of Sciences (India)

    the thermal decomposition behaviour of the aforementioned powder at high heating rates was taken into considera- ... does not change the process of releasing hydrogen from titanium hydride ... from titanium hydride in a sequence of steps.

  16. Coal-Fired Power Plant Heat Rate Reductions

    Science.gov (United States)

    View a report that identifies systems and equipment in coal-fired power plants where efficiency improvements can be realized, and provides estimates of the resulting net plant heat rate reductions and costs for implementation.

  17. Controlling Object Heat Release Rate using Geometrical Features

    OpenAIRE

    Kraft, Stefan Marc

    2017-01-01

    An experimental study was conducted to determine the effect of complex geometries on the burning rate of materials made using additive manufacturing. Controlling heat release rate has applicability in limiting fire hazards as well as for designing fuels for optimal burning rate. The burning rate of a structure is a function of the material properties as well as the airflow through it, which is dictated by the geometry. This burning rate is generally proportional to the porosity for obj...

  18. Characteristics of Vacuum Freeze Drying with Utilization of Internal Cooling and Condenser Waste Heat for Sublimation

    Directory of Open Access Journals (Sweden)

    Muhammad Alhamid

    2013-09-01

    Full Text Available Vacuum freeze drying is an excellent drying method, but it is very energy-intensive because a relatively long drying time is required. This research investigates the utilization of condenser waste heat for sublimation as a way of accelerating the drying rate. In addition, it also investigates the effect of internal cooling combined with vacuum cooling in the pressure reduction process. Jelly fish tentacles were used as the specimen, with different configurations for condenser heat waste and internal cooling valve opening. The results show that heating with condenser heat waste can accelerate the drying rate up to 0.0035 kg/m2.s. In addition, pre-freezing by internal cooling prevents evaporation until the mass of the specimen is 0.47 g and promotes transition of the specimen into the solid phase.

  19. Liquid metal heat transfer in heat exchangers under low flow rate conditions

    International Nuclear Information System (INIS)

    Mochizuki, Hiroyasu

    2015-01-01

    The present paper describes the liquid metal heat transfer in heat exchangers under low flow rate conditions. Measured data from some experiments indicate that heat transfer coefficients of liquid metals at very low Péclet number are much lower than what are predicted by the well-known empirical relations. The cause of this phenomenon was not fully understood for many years. In the present study, one countercurrent-type heat exchanger is analyzed using three, separated countercurrent heat exchanger models: one is a heat exchanger model in the tube bank region, while the upper and lower plena are modeled as two heat exchangers with a single heat transfer tube. In all three heat exchangers, the same empirical correlation is used in the heat transfer calculation on the tube and the shell sides. The Nusselt number, as a function of the Péclet number, calculated from measured temperature and flow rate data in a 50 MW experimental facility was correctly reproduced by the calculation result, when the calculated result is processed in the same way as the experiment. Finally, it is clarified that the deviation is a superficial phenomenon which is caused by the heat transfer in the plena of the heat exchanger. (author)

  20. Optimization between heating load and entropy-production rate for endoreversible absorption heat-transformers

    International Nuclear Information System (INIS)

    Sun Fengrui; Qin Xiaoyong; Chen Lingen; Wu Chih

    2005-01-01

    For an endoreversible four-heat-reservoir absorption heat-transformer cycle, for which a linear (Newtonian) heat-transfer law applies, an ecological optimization criterion is proposed for the best mode of operation of the cycle. This involves maximizing a function representing the compromise between the heating load and the entropy-production rate. The optimal relation between the ecological criterion and the COP (coefficient of performance), the maximum ecological criterion and the corresponding COP, heating load and entropy production rate, as well as the ecological criterion and entropy-production rate at the maximum heating load are derived using finite-time thermodynamics. Moreover, compared with the heating-load criterion, the effects of the cycle parameters on the ecological performance are studied by numerical examples. These show that achieving the maximum ecological criterion makes the entropy-production rate decrease by 77.0% and the COP increase by 55.4% with only 27.3% heating-load losses compared with the maximum heating-load objective. The results reflect that the ecological criterion has long-term significance for optimal design of absorption heat-transformers

  1. Internal heat exchange tubes for industrial furnaces

    Energy Technology Data Exchange (ETDEWEB)

    Hoetzl, M.; Lingle, T.M.

    1992-05-26

    This patent describes a method for cooling the work within an industrial furnace. It comprises providing a longitudinally extending outer tube which extends into the furnace having a closed axial end and an open axial end; providing a preformed inner tube open at both ends within the outer tube; injecting a coolant into the inner tube so that the coolant flows from one axial end of the tube out the opposite end adjacent the closed end of the outer tube, and from the closed end of the outer tube to the open end thereof; circulating a gas within the furnace against the outer tube to effect heat transfer therewith.

  2. SCEPTIC, Pressure Drop, Flow Rate, Heat Transfer, Temperature in Reactor Heat Exchanger

    International Nuclear Information System (INIS)

    Kattchee, N.; Reynolds, W.C.

    1975-01-01

    1 - Nature of physical problem solved: SCEPTIC is a program for calculating pressure drop, flow rates, heat transfer rates, and temperature in heat exchangers such as fuel elements of typical gas or liquid cooled nuclear reactors. The effects of turbulent and heat interchange between flow passages are considered. 2 - Method of solution: The computation procedure amounts to a nodal of lumped parameter type of calculation. The axial mesh size is automatically selected to assure that a prescribed accuracy of results is obtained. 3 - Restrictions on the complexity of the problem: Maximum number of subchannels is 25, maximum number of heated surfaces is 46

  3. History of heat pumps - Swiss contributions and international milestones

    Energy Technology Data Exchange (ETDEWEB)

    Zogg, M

    2008-05-15

    Compared to conventional boilers, heating by heat pumps cuts down fuel consumption and CO{sub 2} emissions to about 50%. Compared to electric resistance heating, the energy consumption is even reduced up to 80%. Therefore, the impressive market penetration growth of heat pumps will continue. Swiss pioneers were the first to realize functioning vapour recompression plants. The first European heat pumps were realized in Switzerland. To date it remains one of the heat pump champions. Swiss pioneering work in the development of borehole heat exchangers, sewage heat recovery, oil free piston compressors and turbo compressors is well known. The biggest heat pump ever built comes from Switzerland. Although there is a fairly comprehensive natural gas distribution grid, 75% of the new single-family homes built in Switzerland are currently heated by heat pumps. This paper presents some of the highlights of this success story focusing on Swiss developments and relating them to the international milestones. In order to indicate the direction in which the future development might go to, some recent Swiss research projects are presented as well. (author)

  4. Experimental and analytical study of natural-convection heat transfer of internally heated liquids

    International Nuclear Information System (INIS)

    Green, G.A.

    1982-08-01

    Boundary heat transfer from a liquid pool with a uniform internal heat source to a vertical or inclined boundary was investigated. The experiments were performed in an open rectangular liquid pool in which the internal heat source was generated by electrical heating. The local heat flux was measured to a boron nitride test wall which was able to be continuously inclined from vertical. Gold plated microthermocouples of 0.01 inch outside diameter were developed to measure the local surface temperature, both front and back, of the boron nitride. The local heat flux and, thus, the local heat transfer coefficient was measured at nineteen locations along the vertical axis of the test plate. A theoretical analysis of the coupled nonlinear boundary layer equations was performed. The parametric effect of the Prandtl number and the dimensionless wall temperature on the boundary heat transfer were investigated When the analytical model was used to calculate the boundary heat transfer data, agreement was achieved with the experimental data within 3% for the local heat transfer and within 2% for the average heat transfer

  5. Heat transfer 1990. Proceedings of the ninth international heat transfer conference

    International Nuclear Information System (INIS)

    Hetsroni, G.

    1990-01-01

    This book contains the proceedings of the Ninth International Heat Transfer Conference. Included in Volume 3 are the following chapters: Refrigerant vapor condensation on a horizontal tube bundle. Local heat transfer in a reflux condensation inside a closed two-phase thermosyphon and surface temperature by means of a pulsed photothermal effects

  6. Heat transfer in intermediate heat exchanger under low flow rate conditions

    International Nuclear Information System (INIS)

    Mochizuki, H.

    2008-01-01

    The present paper describes the heat transfer in intermediate heat exchangers (IHXs) of liquid metal cooled fast reactors when flow rate is low such as a natural circulation condition. Although empirical correlations of heat transfer coefficients for IHX were derived using test data at the fast reactor 'Monju' and 'Joyo' and also at the 50 MW steam generator facility, the heat transfer coefficient was very low compared to the well known correlation for liquid metals proposed by Seban-Shimazaki. The heat conduction in IHX was discussed as a possible cause of the low Nusselt number. As a result, the heat conduction is not significant under the natural circulation condition, and the heat conduction term in the energy equation can be neglected in the one-dimensional plant dynamics calculation. (authors)

  7. Nonlinear throughflow and internal heating effects on vibrating porous medium

    Directory of Open Access Journals (Sweden)

    Palle Kiran

    2016-06-01

    Full Text Available The effect of vertical throughflow and internal heating effects on fluid saturated porous medium under gravity modulation is investigated. The amplitude of modulation is considered to be very small and the disturbances are expanded in terms of power series of amplitude of convection. A weakly nonlinear stability analysis is proposed to study stationary convection. The Nusselt number is obtained numerically to present the results of heat transfer while using Ginzburg–Landau equation. The vertical throughflow has dual effect either to destabilize or to stabilize the system for downward or upward directions. The effect of internal heat source (Ri>0 enhances or sink (Ri<0 diminishes heat transfer in the system. The amplitude and frequency of modulation have the effects of increasing or diminishing heat transport. For linear model Venezian approach suggested that throughflow and internal heating have both destabilizing and stabilizing effects for suitable ranges of Ω. Further, the study establishes that heat transport can be controlled effectively by a mechanism that is external to the system throughflow and gravity modulation.

  8. Heat transfer in a counterflow heat exchanger at low flow rates

    International Nuclear Information System (INIS)

    Hashimoto, A.; Hattori, N.; Naruke, K.

    1995-01-01

    A study was made of heat transfer in a double-tube heat exchanger at low flow rates of water. The temperatures of fluid and tube walls in the axial direction of tube were measured precisely at flow rate ratios of annulus to inner tube (or flow rate ratios of inner tube to annulus W i /W a , Re i approx. = 80 - 4000), W a /W i =0.1 - 1.1. In parallel with experiment, numerical calculation for forced-convection heat transfer was also carried out for laminar flows in the same tube configuration as experiment. Average over-all coefficients of heat transfer, obtained by experiments, indicate the same characteristics as numerical calculation in the examined range of flow rate ratio. Their experimental values, however, are somewhat larger than those of calculation at small values of flow rate ratio. (author)

  9. Performance analysis of an organic Rankine cycle with internal heat exchanger having zeotropic working fluid

    Directory of Open Access Journals (Sweden)

    Thoranis Deethayat

    2015-09-01

    Full Text Available In this study, performance of a 50 kW organic Rankine cycle (ORC with internal heat exchanger (IHE having R245fa/R152a zeotropic refrigerant with various compositions was investigated. The IHE could reduce heat rate at the ORC evaporator and better cycle efficiency could be obtained. The zeotropic mixture could reduce the irreversibilities during the heat exchanges at the ORC evaporator and the ORC condenser due to its gliding temperature; thus the cycle working temperatures came closer to the temperatures of the heat source and the heat sink. In this paper, effects of evaporating temperature, mass fraction of R152a and effectiveness of internal heat exchanger on the ORC performances for the first law and the second law of thermodynamics were considered. The simulated results showed that reduction of R245fa composition could reduce the irreversibilities at the evaporator and the condenser. The suitable composition of R245fa was around 80% mass fraction and below this the irreversibilities were nearly steady. Higher evaporating temperature and higher internal heat exchanger effectiveness also increased the first law and second law efficiencies. A set of correlations to estimate the first and the second law efficiencies with the mass fraction of R245fa, the internal heat exchanger effectiveness and the evaporating temperature were also developed.

  10. r-PROCESS LANTHANIDE PRODUCTION AND HEATING RATES IN KILONOVAE

    Energy Technology Data Exchange (ETDEWEB)

    Lippuner, Jonas; Roberts, Luke F., E-mail: jlippuner@tapir.caltech.edu [TAPIR, Walter Burke Institute for Theoretical Physics, California Institute of Technology, MC 350-17, 1200 E California Boulevard, Pasadena CA 91125 (United States)

    2015-12-20

    r-process nucleosynthesis in material ejected during neutron star mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients depend on the composition of the ejecta, which determines the local heating rate from nuclear decays and the opacity. Kasen et al. and Tanaka and Hotokezaka pointed out that lanthanides can drastically increase the opacity in these outflows. We use the new general-purpose nuclear reaction network SkyNet to carry out a parameter study of r-process nucleosynthesis for a range of initial electron fractions Y{sub e}, initial specific entropies s, and expansion timescales τ. We find that the ejecta is lanthanide-free for Y{sub e} ≳ 0.22−0.30, depending on s and τ. The heating rate is insensitive to s and τ, but certain, larger values of Y{sub e} lead to reduced heating rates, due to individual nuclides dominating the heating. We calculate approximate light curves with a simplified gray radiative transport scheme. The light curves peak at about a day (week) in the lanthanide-free (-rich) cases. The heating rate does not change much as the ejecta becomes lanthanide-free with increasing Y{sub e}, but the light-curve peak becomes about an order of magnitude brighter because it peaks much earlier when the heating rate is larger. We also provide parametric fits for the heating rates between 0.1 and 100 days, and we provide a simple fit in Y{sub e}, s, and τ to estimate whether or not the ejecta is lanthanide-rich.

  11. r-PROCESS LANTHANIDE PRODUCTION AND HEATING RATES IN KILONOVAE

    International Nuclear Information System (INIS)

    Lippuner, Jonas; Roberts, Luke F.

    2015-01-01

    r-process nucleosynthesis in material ejected during neutron star mergers may lead to radioactively powered transients called kilonovae. The timescale and peak luminosity of these transients depend on the composition of the ejecta, which determines the local heating rate from nuclear decays and the opacity. Kasen et al. and Tanaka and Hotokezaka pointed out that lanthanides can drastically increase the opacity in these outflows. We use the new general-purpose nuclear reaction network SkyNet to carry out a parameter study of r-process nucleosynthesis for a range of initial electron fractions Y e , initial specific entropies s, and expansion timescales τ. We find that the ejecta is lanthanide-free for Y e ≳ 0.22−0.30, depending on s and τ. The heating rate is insensitive to s and τ, but certain, larger values of Y e lead to reduced heating rates, due to individual nuclides dominating the heating. We calculate approximate light curves with a simplified gray radiative transport scheme. The light curves peak at about a day (week) in the lanthanide-free (-rich) cases. The heating rate does not change much as the ejecta becomes lanthanide-free with increasing Y e , but the light-curve peak becomes about an order of magnitude brighter because it peaks much earlier when the heating rate is larger. We also provide parametric fits for the heating rates between 0.1 and 100 days, and we provide a simple fit in Y e , s, and τ to estimate whether or not the ejecta is lanthanide-rich

  12. Experimental study on local heat transfer characteristics of porous media with internal heat source

    International Nuclear Information System (INIS)

    Zan Yuanfeng; Wang Taotao; Xiao Zejun; Wang Fei; Huang Yanping

    2008-01-01

    Model of porous media with internal heat source is established. The model uses water as flowing media, and the stainless steel test section is packed with steel spheres in manner of regular triangle, respectively. The armoured resistance wire is inserted inside the steel sphere. On the basis of the experimental model, many parameters of the local heat transfer characteristics including current velocity and wall temperature of steel sphere are measured. The experimental results show that the coefficient of heat transfer scarcely changes with pressure. The coefficient of heat transfer increases with the surface heat flux of steel sphere. When raising the inlet temperature of the cooling water, the coefficient of heat transfer presents the descending trend. In addition, the influence of entrance effect on heat transfer is discovered in the experiment, which is much less than the liquid flow in the light tube. After experiment data are analyzed and processed, the relation model of heat transfer on local heat transfer characteristic of porous media with internal heat source was described with a power-law-equation. The deviations between calculation and experimental values are within ±10%. (authors)

  13. Evaluation of Criticality of Self-Heating of Polymer Composites by Estimating the Heat Dissipation Rate

    Science.gov (United States)

    Katunin, A.

    2018-03-01

    The critical self-heating temperature at which the structural degradation of polymer composites under cyclic loading begins is evaluated by analyzing the heat dissipation rate. The method proposed is an effective tool for evaluating the degradation degree of such structures.

  14. Single-phase convection heat transfer characteristics of pebble-bed channels with internal heat generation

    International Nuclear Information System (INIS)

    Meng Xianke; Sun Zhongning; Xu Guangzhan

    2012-01-01

    Graphical abstract: The core of the water-cooled pebble bed reactor is the porous channels which stacked with spherical fuel elements. The gaps between the adjacent fuel elements are complex because they are stochastic and often shift. We adopt electromagnetic induction heating method to overall heat the pebble bed. By comparing and analyzing the experimental data, we get the rule of power distribution and the rule of heat transfer coefficient with particle diameter, heat flux density, inlet temperature and working fluid's Re number. Highlights: ► We adopt electromagnetic induction heating method to overall heat the pebble bed to be the internal heat source. ► The ball diameter is smaller, the effect of the heat transfer is better. ► With Re number increasing, heat transfer coefficient is also increasing and eventually tends to stabilize. ► The changing of heat power makes little effect on the heat transfer coefficient of pebble bed channels. - Abstract: The reactor core of a water-cooled pebble bed reactor includes porous channels that are formed by spherical fuel elements. This structure has notably improved heat transfer. Due to the variability and randomness of the interstices in pebble bed channels, heat transfer is complex, and there are few studies regarding this topic. To study the heat transfer characters of pebble bed channels with internal heat sources, oxidized stainless steel spheres with diameters of 3 and 8 mm and carbon steel spheres with 8 mm diameters are used in a stacked pebble bed. Distilled water is used as a refrigerant for the experiments, and the electromagnetic induction heating method is used to heat the pebble bed. By comparing and analyzing the experimental results, we obtain the governing rules for the power distribution and the heat transfer coefficient with respect to particle diameter, heat flux density, inlet temperature and working fluid Re number. From fitting of the experimental data, we obtain the dimensionless average

  15. Network model of free convection within internally heated porous media

    International Nuclear Information System (INIS)

    Conrad, P.W.

    1977-01-01

    A hypothetical core-disruptive accident (HCDA) in a liquid metal fast breeder reactor (LMFBR) may result in the formation of an internally heated debris bed. Considerable attention has been given to postulated mechanisms by which such beds may be cooled. It is the purpose of the work described to demonstrate a method for computing the heat transfer from such a bed to the overlying sodium pool due to single-phase, free convection

  16. Work Rate during Self-paced Exercise is not Mediated by the Rate of Heat Storage.

    Science.gov (United States)

    Friesen, Brian J; Périard, Julien D; Poirier, Martin P; Lauzon, Martin; Blondin, Denis P; Haman, Francois; Kenny, Glen P

    2018-01-01

    To date, there have been mixed findings on whether greater anticipatory reductions in self-paced exercise intensity in the heat are mediated by early differences in rate of body heat storage. The disparity may be due to an inability to accurately measure minute-to-minute changes in whole-body heat loss. Thus, we evaluated whether early differences in rate of heat storage can mediate exercise intensity during self-paced cycling at a fixed rate of perceived exertion (RPE of 16; hard-to-very-hard work effort) in COOL (15°C), NORMAL (25°C), and HOT (35°C) ambient conditions. On separate days, nine endurance-trained cyclists exercised in COOL, NORMAL, and HOT conditions at a fixed RPE until work rate (measured after first 5 min of exercise) decreased to 70% of starting values. Whole-body heat loss and metabolic heat production were measured by direct and indirect calorimetry, respectively. Total exercise time was shorter in HOT (57 ± 20 min) relative to both NORMAL (72 ± 23 min, P = 0.004) and COOL (70 ± 26 min, P = 0.045). Starting work rate was lower in HOT (153 ± 31 W) compared with NORMAL (166 ± 27 W, P = 0.024) and COOL (170 ± 33 W, P = 0.037). Rate of heat storage was similar between conditions during the first 4 min of exercise (all P > 0.05). Thereafter, rate of heat storage was lower in HOT relative to NORMAL and COOL until 30 min of exercise (last common time-point between conditions; all P exercise. No differences were measured at end exercise. We show that rate of heat storage does not mediate exercise intensity during self-paced exercise at a fixed RPE in cool to hot ambient conditions.

  17. Effect of mineral matter on coal self-heating rate

    Energy Technology Data Exchange (ETDEWEB)

    B. Basil Beamish; Ahmet Arisoy [University of Queensland, Brisbane, Qld. (Australia). School of Engineering

    2008-01-15

    Adiabatic self-heating tests have been conducted on subbituminous coal cores from the same seam profile, which cover a mineral matter content range of 11.2-71.1%. In all cases the heat release rate does not conform to an Arrhenius kinetic model, but can best be described by a third order polynomial. Assessment of the theoretical heat sink effect of the mineral matter in each of the tests reveals that the coal is less reactive than predicted using a simple energy conservation equation. There is an additional effect of the mineral matter in these cases that cannot be explained by heat sink alone. The disseminated mineral matter in the coal is therefore inhibiting the oxidation reaction due to physicochemical effects. 14 refs., 5 figs., 5 tabs.

  18. Money market rates and implied CCAPM rates: some international evidence

    OpenAIRE

    Yamin Ahmad

    2004-01-01

    New Neoclassical Synthesis models equate the instrument of monetary policy to the implied CCAPM rate arising from an Euler equation. This paper identifies monetary policy shocks within six of the G7 countries and examines the movement of money market and implied CCAPM rates. The key result is that an increase in the nominal interest rate leads to a fall in the implied CCAPM rate. Incorporating habit still yields the same result. The findings suggest that the movement of these two rates implie...

  19. Thermal mechanical analysis of applications with internal heat generation

    Science.gov (United States)

    Govindarajan, Srisharan Garg

    The radioactive tracer Technetium-99m is widely used in medical imaging and is derived from its parent isotope Molybedenum-99 (Mo-99) by radioactive decay. The majority of Molybdenum-99 (Mo-99) produced internationally is extracted from high enriched uranium (HEU) dispersion targets that have been irradiated. To alleviate proliferation risks associated with HEU-based targets, the use of non-HEU sources is being mandated. However, the conversion of HEU to LEU based dispersion targets affects the Mo-99 available for chemical extraction. A possible approach to increase the uranium density, to recover the loss in Mo-99 production-per-target, is to use an LEU metal foil placed within an aluminum cladding to form a composite structure. The target is expected to contain the fission products and to dissipate the generated heat to the reactor coolant. In the event of interfacial separation, an increase in the thermal resistance could lead to an unacceptable rise in the LEU temperature and stresses in the target. The target can be deemed structurally safe as long as the thermally induced stresses are within the yield strength of the cladding and welds. As with the thermal and structural safety of the annular target, the thermally induced deflection of the BORALRTM-based control blades, used by the University of Missouri Research Reactor (MURRRTM ), during reactor operation has been analyzed. The boron, which is the neutron absorber in BORAL, and aluminum mixture (BORAL meat) and the aluminum cladding are bonded together through powder metallurgy to establish an adherent bonded plate. As the BORAL absorbs both neutron particles and gamma rays, there is volumetric heat generation and a corresponding rise in temperature. Since the BORAL meat and aluminum cladding materials have different thermal expansion coefficients, the blade may have a tendency to deform as the blade temperature changes and the materials expand at different rates. In addition to the composite nature of the

  20. An analysis of representative heating load lines for residential HSPF ratings

    Energy Technology Data Exchange (ETDEWEB)

    Rice, C. Keith [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shen, Bo [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Shrestha, Som S. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-07-01

    This report describes an analysis to investigate representative heating loads for single-family detached homes using current EnergyPlus simulations (DOE 2014a). Hourly delivered load results are used to determine binned load lines using US Department of Energy (DOE) residential prototype building models (DOE 2014b) developed by Pacific Northwest National Laboratory (PNNL). The selected residential single-family prototype buildings are based on the 2006 International Energy Conservation Code (IECC 2006) in the DOE climate regions. The resulting load lines are compared with the American National Standards Institute (ANSI)/Air-Conditioning, Heating, and Refrigeration Institute (AHRI) Standard 210/240 (AHRI 2008) minimum and maximum design heating requirement (DHR) load lines of the heating seasonal performance factor (HSPF) ratings procedure for each region. The results indicate that a heating load line closer to the maximum DHR load line, and with a lower zero load ambient temperature, is more representative of heating loads predicted for EnergyPlus prototype residential buildings than the minimum DHR load line presently used to determine HSPF ratings. An alternative heating load line equation was developed and compared to binned load lines obtained from the EnergyPlus simulation results. The effect on HSPF of the alternative heating load line was evaluated for single-speed and two-capacity heat pumps, and an average HSPF reduction of 16% was found. The alternative heating load line relationship is tied to the rated cooling capacity of the heat pump based on EnergyPlus autosizing, which is more representative of the house load characteristics than the rated heating capacity. The alternative heating load line equation was found to be independent of climate for the six DOE climate regions investigated, provided an adjustable zero load ambient temperature is used. For Region IV, the default DOE climate region used for HSPF ratings, the higher load line results in an ~28

  1. Sensitivity of tropospheric heating rates to aerosols: A modeling study

    International Nuclear Information System (INIS)

    Hanna, A.F.; Shankar, U.; Mathur, R.

    1994-01-01

    The effect of aerosols on the radiation balance is critical to the energetics of the atmosphere. Because of the relatively long residence of specific types of aerosols in the atmosphere and their complex thermal and chemical interactions, understanding their behavior is crucial for understanding global climate change. The authors used the Regional Particulate Model (RPM) to simulate aerosols in the eastern United States in order to identify the aerosol characteristics of specific rural and urban areas these characteristics include size, concentration, and vertical profile. A radiative transfer model based on an improved δ-Eddington approximation with 26 spectral intervals spanning the solar spectrum was then used to analyze the tropospheric heating rates associated with these different aerosol distributions. The authors compared heating rates forced by differences in surface albedo associated with different land-use characteristics, and found that tropospheric heating and surface cooling are sensitive to surface properties such as albedo

  2. International Energy Agency Solar Heating and Cooling Program

    Science.gov (United States)

    Brooks, A. J.

    This trip was undertaken to participate in and represent the United States Industry at the International Energy Agency (IEA) Solar Heating and Cooling Program (SHCP) Task 14 Workshop. The meeting took place at the A1 Bani Hotel in Rome Italy.

  3. Analysis of natural convection heat transfer and flows in internally heated stratified liquid pools

    International Nuclear Information System (INIS)

    Gubaidullin, A.A. Jr.; Dinh, T.N.; Sehgal, B.R.

    1999-01-01

    In this paper, natural convection flows and heat transfer in a liquid pool, with two superposed immiscible fluid layers, are analyzed. The objective of the study is to examine the effect of interfacial hydrodynamics and to develop a method which enables energy splitting to be evaluated in a stratified liquid pool. The thermal convection, with and without an internal heat source, in a rectangular cavity with different pairs of fluids was numerically simulated by a CFD code FLOW-3D. It was found that the code performs very well for prediction of heat transfer coefficients for different conditions. The hydrodynamic coupling between immiscible layers was found to have minor, if any, impact on the natural convection heat transfer for the conditions examined. Calculated results were used to develop, and validate, a new correlation for energy splitting and for heat transfer in stratified liquid pools

  4. International convergence of capital market interest rates.

    NARCIS (Netherlands)

    Fase, M.M.G.; Vlaar, P.J.G.

    1997-01-01

    This article investigates the extent of capital market interest rate convergence among six EU countries on the one hand, and a group of four countries with floating exchange rates - US, Germany, Japan and Switzerland - on the other. We conclude that interest rate changes within the EU have been and

  5. Prediction of strongly-heated internal gas flows

    International Nuclear Information System (INIS)

    McEligot, D.M.; Shehata, A.M.; Kunugi, Tomoaki

    1997-01-01

    The purposes of the present article are to remind practitioners why the usual textbook approaches may not be appropriate for treating gas flows heated from the surface with large heat fluxes and to review the successes of some recent applications of turbulence models to this case. Simulations from various turbulence models have been assessed by comparison to the measurements of internal mean velocity and temperature distributions by Shehata for turbulent, laminarizing and intermediate flows with significant gas property variation. Of about fifteen models considered, five were judged to provide adequate predictions

  6. International symposium on radiative heat transfer: Book of abstracts

    International Nuclear Information System (INIS)

    1995-01-01

    The international symposium on radiative heat transfer was held on 14-18 August 1995 Turkey. The specialists discussed radiation transfer in materials processing and manufacturing, solution of radiative heat transfer equation, transient radiation problem and radiation-turbulence interactions, raditive properties of gases, atmospheric and stellar radiative transfer , radiative transfer and its applications, optical and radiative properties of soot particles, inverse radiation problems, partticles, fibres,thermophoresis and waves and modelling of comprehensive systems at the meeting. Almost 79 papers were presented in the meeting

  7. Decay heat rates calculated using ORIGEN-S and CINDER10 with common data libraries

    International Nuclear Information System (INIS)

    Brady, M.C.; Hermann, O.W.; Beard, C.A.; Bohnhoff, W.J.; England, T.R.

    1991-01-01

    A set of two benchmark problems were proposed as part of an international comparison of decay heat codes. Problem specifications included explicit fission-yield, decay and capture data libraries to be used in the calculations. This paper describes the results obtained using these common data to perform the benchmark calculations with two popular depletion codes, ORIGEN-S and CINDER10. Short descriptions of the methods used by each of these codes are also presented. Results from other contributors to the international comparison are discussed briefly. This comparison of decay heat codes using common data libraries demonstrates that discrepant results in calculated decay heat rates are the result of differences in the nuclear data input to the codes and not the method of solution. 15 refs., 2 figs., 8 tabs

  8. Heat release rate from the combustion of uranium

    International Nuclear Information System (INIS)

    Solbrig, C.W.

    1995-01-01

    Fuel treatment is planned at the Argonne National Laboratory on EBR-II spent fuel. The electrochemical treatment process is carried out in a cell with an argon atmosphere to prevent any reaction. The amount of fuel processed at any time is limited by the amount of energy which could be released by metal combustion if air is inadvertently allowed into the cell since the heat release would increase the cell pressure. The cell pressure is required to be below atmospheric even if combustion occurs to ensure no cell gas/aerosol is released to the environment. Metal fires can release large amounts of heat. In certain configurations such as fine particulate, metal can be pyrophoric at room temperature. When the metal is a nuclear fuel, it is important to be able to predict the reaction/heat release rate if the metal is inadvertently exposed to air. A realistic combustion model is needed to predict heat release rates for the many different flow and transport configurations which exist in the various fuel processing steps. A model for the combustion of uranium is developed here which compares satisfactorily to experimental data

  9. 8th International Symposium on Heating, Ventilation and Air Conditioning

    CERN Document Server

    Zhu, Yingxin; Li, Yuguo; Vol.1 Indoor and Outdoor Environment; Vol.2 HVAC&R Component and Energy System; Vol.3 Building Simulation and Information Management

    2014-01-01

    Proceedings of the 8th International Symposium on Heating, Ventilation and Air Conditioning is based on the 8th International Symposium of the same name (ISHVAC2013), which took place in Xi’an on October 19-21, 2013. The conference series was initiated at Tsinghua University in 1991 and has since become the premier international HVAC conference initiated in China, playing a significant part in the development of HVAC and indoor environmental research and industry around the world. This international conference provided an exclusive opportunity for policy-makers, designers, researchers, engineers and managers to share their experience. Considering the recent attention on building energy consumption and indoor environments, ISHVAC2013 provided a global platform for discussing recent research on and developments in different aspects of HVAC systems and components, with a focus on building energy consumption, energy efficiency and indoor environments. These categories span a broad range of topics, and the proce...

  10. An Internally Heated Shape Memory Polymer Dry Adhesive

    Directory of Open Access Journals (Sweden)

    Jeffrey Eisenhaure

    2014-08-01

    Full Text Available A conductive epoxy-based shape memory polymer (SMP is demonstrated using carbon black (CB as a dopant for the purpose of creating an SMP dry adhesive system which can internally generate the heat required for activation. The electrical and mechanical properties of the CB/SMP blends for varying dopant concentrations are characterized. A composite adhesive is created to minimize surface contact resistance to conductive tape acting as electrodes, while maintaining bulk resistivity required for heat generation due to current flow. The final adhesive can function on flat or curved surfaces. As a demonstration, a 25 mm wide by 45 mm long dry adhesive strip is shown to heat evenly from an applied voltage, and can easily hold a mass in excess of 6 kg when bonded to a spherical concave glass surface using light pressure at 75 °C.

  11. Exchange rate volatility and international trade: The option approach

    OpenAIRE

    Franke, Günter

    1986-01-01

    Usually it is argued that an increase in exchange rate volatility reduces the volume of international trade since trading firms are risk averse. This paper shows for risk neutral firms that the expected international trade volume in standardized commodities grows with exchange rate volatility. The firms adjust their trade volume to the exchange rate level. The more favorable the exchange rate is, the higher is the export volume. If the rate drops below some level, exports are stopped. Thus in...

  12. Effects of Heating Rate on the Dynamic Tensile Mechanical Properties of Coal Sandstone during Thermal Treatment

    Directory of Open Access Journals (Sweden)

    Ming Li

    2017-01-01

    Full Text Available The effects of coal layered combustion and the heat injection rate on adjacent rock were examined in the process of underground coal gasification and coal-bed methane mining. Dynamic Brazilian disk tests were conducted on coal sandstone at 800°C and slow cooling from different heating rates by means of a Split Hopkinson Pressure Bar (SHPB test system. It was discovered that thermal conditions had significant effects on the physical and mechanical properties of the sandstone including longitudinal wave velocity, density, and dynamic linear tensile strength; as the heating rates increased, the thermal expansion of the sandstone was enhanced and the damage degree increased. Compared with sandstone at ambient temperature, the fracture process of heat-treated sandstone was more complicated. After thermal treatment, the specimen had a large crack in the center and cracks on both sides caused by loading; the original cracks grew and mineral particle cracks, internal pore geometry, and other defects gradually appeared. With increasing heating rates, the microscopic fracture mode transformed from ductile fracture to subbrittle fracture. It was concluded that changes in the macroscopic mechanical properties of the sandstone were result from changes in the composition and microstructure.

  13. Smoke Movement in an Atrium with a Fire with Low Rate of Heat Release

    DEFF Research Database (Denmark)

    Nielsen, Peter V.; Brohus, Henrik; Petersen, A. J.

    2008-01-01

    Results from small-scale experiments on smoke movement in an atrium are given, both with and without a vertical temperature gradient, and expressions for the smoke movement are developed on the basis of these experiments. Comparisons with a general analytical expression used for calculating...... the height to the location of the smoke layer are given. Furthermore, the paper discusses the air movement in a typical atrium exposed to different internal and external heat loads to elaborate on the use of the "flow element" expressions developed for smoke movement from a fire with a low rate of heat...

  14. Particle loading rates for HVAC filters, heat exchangers, and ducts.

    Science.gov (United States)

    Waring, M S; Siegel, J A

    2008-06-01

    The rate at which airborne particulate matter deposits onto heating, ventilation, and air-conditioning (HVAC) components is important from both indoor air quality (IAQ) and energy perspectives. This modeling study predicts size-resolved particle mass loading rates for residential and commercial filters, heat exchangers (i.e. coils), and supply and return ducts. A parametric analysis evaluated the impact of different outdoor particle distributions, indoor emission sources, HVAC airflows, filtration efficiencies, coils, and duct system complexities. The median predicted residential and commercial loading rates were 2.97 and 130 g/m(2) month for the filter loading rates, 0.756 and 4.35 g/m(2) month for the coil loading rates, 0.0051 and 1.00 g/month for the supply duct loading rates, and 0.262 g/month for the commercial return duct loading rates. Loading rates are more dependent on outdoor particle distributions, indoor sources, HVAC operation strategy, and filtration than other considered parameters. The results presented herein, once validated, can be used to estimate filter changing and coil cleaning schedules, energy implications of filter and coil loading, and IAQ impacts associated with deposited particles. The results in this paper suggest important factors that lead to particle deposition on HVAC components in residential and commercial buildings. This knowledge informs the development and comparison of control strategies to limit particle deposition. The predicted mass loading rates allow for the assessment of pressure drop and indoor air quality consequences that result from particle mass loading onto HVAC system components.

  15. Heat-induced electron emission in paraelectric phase of triglycine sulfate heated with great rate

    CERN Document Server

    Sidorkin, A A; Rogazinskaya, O V; Milovidova, S D

    2002-01-01

    One recorded experimentally heat-induced electron emission in ferroelectric triglycine sulfate (TGS) crystal within temperature range exceeding the Curie point by 10-15 K. One studied cases of q = dT/dt various rates of linear heating of specimens of TGS nominally pure crystal and TGS crystal with chromium impurity. Increase of heating rate is shown to result in increase of emission current density within the whole investigated range of temperatures. Temperature of emission occurrence depends on q rate negligibly. At the same time, temperature of emission disappearance monotonically increases with q growth. At q below 1 K/min it is localized below the Curie point. At q = 4-5 K/min the mentioned temperature reaches 60-65 deg C. In TGS crystal with chromium impurity the temperature of emission occurrence is close to the case of pure TGS. In this case, the range of emission drawing in paraphase here is by about 2 times narrower in contrast to the case of pure TGS heated with the same rate

  16. International trade and exchange rate volatility

    NARCIS (Netherlands)

    J.M.A. Viaene (Jean-Marie); C.G. de Vries (Casper)

    1992-01-01

    textabstractFor currencies with well developed forward markets several papers have investigated the conjectured negative relationship between trade and short term exchange rate volatility, without being very successful. A theoretical explanation for the empirical anomalies is provided by solving

  17. Internal heat gain from different light sources in the building lighting systems

    Directory of Open Access Journals (Sweden)

    Suszanowicz Dariusz

    2017-01-01

    Full Text Available EU directives and the Construction Law have for some time required investors to report the energy consumption of buildings, and this has indeed caused low energy consumption buildings to proliferate. Of particular interest, internal heat gains from installed lighting affect the final energy consumption for heating of both public and residential buildings. This article presents the results of analyses of the electricity consumption and the luminous flux and the heat flux emitted by different types of light sources used in buildings. Incandescent light, halogen, compact fluorescent bulbs, and LED bulbs from various manufacturers were individually placed in a closed and isolated chamber, and the parameters for their functioning under identical conditions were recorded. The heat flux emitted by 1 W nominal power of each light source was determined. Based on the study results, the empirical coefficients of heat emission and energy efficiency ratios for different types of lighting sources (dependent lamp power and the light output were designated. In the heat balance of the building, the designated rates allow for precise determination of the internal heat gains coming from lighting systems using various light sources and also enable optimization of lighting systems of buildings that are used in different ways.

  18. Internal heat gain from different light sources in the building lighting systems

    Science.gov (United States)

    Suszanowicz, Dariusz

    2017-10-01

    EU directives and the Construction Law have for some time required investors to report the energy consumption of buildings, and this has indeed caused low energy consumption buildings to proliferate. Of particular interest, internal heat gains from installed lighting affect the final energy consumption for heating of both public and residential buildings. This article presents the results of analyses of the electricity consumption and the luminous flux and the heat flux emitted by different types of light sources used in buildings. Incandescent light, halogen, compact fluorescent bulbs, and LED bulbs from various manufacturers were individually placed in a closed and isolated chamber, and the parameters for their functioning under identical conditions were recorded. The heat flux emitted by 1 W nominal power of each light source was determined. Based on the study results, the empirical coefficients of heat emission and energy efficiency ratios for different types of lighting sources (dependent lamp power and the light output) were designated. In the heat balance of the building, the designated rates allow for precise determination of the internal heat gains coming from lighting systems using various light sources and also enable optimization of lighting systems of buildings that are used in different ways.

  19. Heat and mass transfer analogies for evaporation models at high evaporation rate

    OpenAIRE

    Trontin , P.; Villedieu , P.

    2014-01-01

    International audience; In the framework of anti and deicing applications, heated liquid films can appear above the ice thickness, or directly above the wall. Then, evaporation plays a major role in the Messinger balance and evaporated mass has to be predicted accurately. Unfortunately, it appears that existing models under-estimate evaporation at high temperature. In this study, different evaporation models at high evaporation rates are studied. The different hypothesis on which these models...

  20. Experimental study on single-phase convection heat transfer characteristics of pebble bed channels with internal heat generation

    International Nuclear Information System (INIS)

    Meng Xianke; Sun Zhongning; Zhou Ping; Xu Guangzhan

    2012-01-01

    The water-cooled pebble bed reactor core is the porous channels stacked with spherical fuel elements, having evident effect on enhancing heat transfer. Owing to the variability and randomness characteristics of it's interstice, pebble bed channels have a very complex heat transfer situation and have little correlative research. In order to research the heat transfer characters of pebble bed channels with internal heat source, electromagnetic induction heating method was adopted for overall heating the pebble bed which was composed of 8 mm diameter steel balls, and the internal heat transfer characteristics were researched. By comparing and analyzing the experimental data, the rule of power distribution and heat transfer coefficient with heat flux density, inlet temperature and working fluid's Re were got. According to the experimental data fitting, the dimensionless average heat transfer coefficient correlation criteria was got. The fitting results are good agreement with the experimental results within 12% difference. (authors)

  1. INTERNATIONAL RATINGS IN DETERMINING THE FINANCIAL STABILITY OF UKRAINE

    Directory of Open Access Journals (Sweden)

    N. Plieshakova

    2014-01-01

    Full Text Available Problem of the global financial stability and position of Ukraine in international ratings are considered in the paper. Impact of ratings assessment on the financial stability of the country in general is analysed.

  2. Effect of heating rate on caustic stress corrosion cracking

    International Nuclear Information System (INIS)

    Indig, M.E.; Hoffman, N.J.

    1977-01-01

    To evaluate effects of a large water leak into the sodium side of a steam generator in a Liquid Metal Fast Breeder Reactor the Liquid Metal Engineering Center (LMEC) at Canoga Park, California, is performing a series of tests in a Large Leak Test Rig (LLTR). This test series involves heating a large steam generator that possibly contains localized pockets of aqueous caustic retained from a previous sodium-water reaction. Such pockets of caustic solution could be in contact with welds and other components that contain residual stresses up to the yield point. The LMEC and General Electric (GE) ran a series of tests to evaluate the effect of heating rate on caustic stress corrosion cracking (SCC) for alloys either used or considered for the LLTR. A summary of the temperatures and caustic concentration ranges that can result in caustic SCC for carbon steel and Type-304 stainless steel is given

  3. Heat transfer measurements of internally heated liquids in cylindrical convection cells

    International Nuclear Information System (INIS)

    Fieg, G.

    1978-10-01

    In hypothetical reactor accidents, the thermohydraulic behaviour of core melts heated by the after-heat must be analyzed. For this purpose model experiments have been performed to study the stationary, natural convective heat transfer of internally heated fluids in cylindrical convertion cells investigating also the influence of geometry (aspect ratio) as well as of difference thermal wall conditions on to the heat transport characteristics. Axial temperature profiles, local heat flux densities at the vertical walls and their dependence, on the external Rayleigh number ar in detail reported, besides the Nusselt vs Rayleigh correlations for the aspect ratios HID=1 and 0,25. The results of these experiments are compared, as for ar possible, with existing thermohydraulic codes and simpler model asoumptions like the zone-model of Baker et. al. and after experimental verification, be used to study realistic PAHR situations. Velocity measurements by means of Laser-Doppler-Method yield information about the flow characteristics near the vertical walls and within the central part of the convecting fluid. (GL) [de

  4. Analysis of Water Recovery Rate from the Heat Melt Compactor

    Science.gov (United States)

    Balasubramaniam, R.; Hegde, U.; Gokoglu, S.

    2013-01-01

    any remaining free water in the trash by evaporation. The temperature settings of the heated surfaces are usually kept above the saturation temperature of water but below the melting temperature of the plastic in the waste during this step to avoid any encapsulation of wet trash which would reduce the amount of recovered water by blocking the vapor escape. In this paper, we analyze the water recovery rate during Phase B where the trash is heated and water leaves the waste chamber as vapor, for operation of the HMC in reduced gravity. We pursue a quasi-one-dimensional model with and without sidewall heating to determine the water recovery rate and the trash drying time. The influences of the trash thermal properties, the amount of water loading, and the distribution of the water in the trash on the water recovery rates are determined.

  5. Solar Flux Deposition And Heating Rates In Jupiter's Atmosphere

    Science.gov (United States)

    Perez-Hoyos, Santiago; Sánchez-Lavega, A.

    2009-09-01

    We discuss here the solar downward net flux in the 0.25 - 2.5 µm range in the atmosphere of Jupiter and the associated heating rates under a number of vertical cloud structure scenarios focusing in the effect of clouds and hazes. Our numerical model is based in the doubling-adding technique to solve the radiative transfer equation and it includes gas absorption by CH4, NH3 and H2, in addition to Rayleigh scattering by a mixture of H2 plus He. Four paradigmatic Jovian regions have been considered (hot-spots, belts, zones and Polar Regions). The hot-spots are the most transparent regions with downward net fluxes of 2.5±0.5 Wm-2 at the 6 bar level. The maximum solar heating is 0.04±0.01 K/day and occurs above 1 bar. Belts and zones characterization result in a maximum net downward flux of 0.5 Wm-2 at 2 bar and 0.015 Wm-2 at 6 bar. Heating is concentrated in the stratospheric and tropospheric hazes. Finally, Polar Regions are also explored and the results point to a considerable stratospheric heating of 0.04±0.02 K/day. In all, these calculations suggest that the role of the direct solar forcing in the Jovian atmospheric dynamics is limited to the upper 1 - 2 bar of the atmosphere except in the hot-spot areas. Acknowledgments: This work has been funded by Spanish MEC AYA2006-07735 with FEDER support and Grupos Gobierno Vasco IT-464-07.

  6. Waste heat recovery systems for internal combustion engines: classification and benefits

    OpenAIRE

    Marchenko, A.; Samoilenko, D.; Adel Hamzah, Ali; Adel Hamzah, Omar

    2014-01-01

    Recent trend about the best ways of using the deployable sources of energy in to useful work in order to reduce the rate of consumption of fossil fuel as well as pollution. Out of all the available sources, the internal combustion engines are the major consumer of fossil fuel around the globe. The remaining heat is expelled to the environment through exhaust gases and engine cooling systems, resulting in to entropy rise and serious environmental pollution, so it is required to utilized waste ...

  7. Design of internally heat-integrated distillation column (HIDiC): Uniform heat transfer area versus uniform heat distribution

    Energy Technology Data Exchange (ETDEWEB)

    Suphanit, B. [Department of Chemical Engineering, Faculty of Engineering, King Mongkut' s University of Technology Thonburi, Pracha Utit Rd., Tungkru, Bangkok 10140 (Thailand)

    2010-03-15

    The internally heat-integrated distillation column (HIDiC) is a complex column configuration which is more energy efficient than the equivalent conventional column or the distillation column with direct vapor recompression scheme (VRC). Exploiting the heat integration between two diabatic sections operating at different pressures of the HIDiC can greatly enhance the energy performance of the system. On the other hand, the design and optimization of HIDiC is more difficult than those of the conventional distillation column or the column with VRC. The former involves many design parameters, and the most critical one is the pressure ratio between both diabatic sections. However, the heat distribution along the diabatic sections is also another significant factor not yet thoroughly investigated. In this work, two typical distribution schemes, i.e. uniform heat transfer area and uniform heat distribution, are studied by applying a novel approach to solve the simulation problem in Aspen Plus 2004.1. The comparison of both distributing schemes is discussed via two widely-used case studies, namely benzene-toluene separation and propylene-propane splitter. (author)

  8. Data for occupancy internal heat gain calculation in main building categories

    Directory of Open Access Journals (Sweden)

    Kaiser Ahmed

    2017-12-01

    Full Text Available Heat losses from occupant body by means of convection, radiation, vapor, and sweat are essential data for indoor climate and energy simulations. Heat losses depend on the metabolic activity and body surface area. Higher variations of body surface area of occupants are observed in day care centers, kinder gardens and schools compared to other building categories (Tables 2 and 3 and these variations need to be accounted, otherwise in these building categories heat gains, CO2 and humidity generation are overestimated. Indoor temperature, humidity level, air velocity, and clothing insulation have significant influences on dry and total heat losses from occupant body leading to typical values for summer and winter. The data presented in this article are related to the research article entitled Occupancy schedules for energy simulation in new prEN16798-1 and ISO/FDIS 17772-1 standards (Ahmed et al., 2017 [1]. Keywords: Body surface area, Metabolic rate, Dry heat loss, Total heat loss, Internal heat gain

  9. Conjugated heat transfer of natural convection in pool with internal heat sources and convection in the tube

    International Nuclear Information System (INIS)

    Li Longjian; Liu Hongtao; Cui Wenzhi

    2007-01-01

    The conjugated heat transfer of natural convection in pool with internal heat source and the forced convection in the tube was analyzed, and the corresponding three-dimensional physical and mathematical model was proposed. A control volume based finite element method was employed to solve numerically the problem. The computations were performed for different internal heat source intensity of the pool and the different flow velocity in the tube. The computed heat transfer coefficients on the inner and outer wall showed well consistency of those calculated with the empirical correlations. Compared with the measured total heat transfer coefficients between the fluids in and out of the tube, the computed ones showed also the well consistency, which implied that the numerical model proposed in this paper was reliable. The research results revealed that the total heat transfer coefficients between the fluids were strongly affected by the internal heat source intensity of the pool liquid and the flow velocity in the tube. (authors)

  10. Development of a national anthropogenic heating database with an extrapolation for international cities

    Science.gov (United States)

    Sailor, David J.; Georgescu, Matei; Milne, Jeffrey M.; Hart, Melissa A.

    2015-10-01

    Given increasing utility of numerical models to examine urban impacts on meteorology and climate, there exists an urgent need for accurate representation of seasonally and diurnally varying anthropogenic heating data, an important component of the urban energy budget for cities across the world. Incorporation of anthropogenic heating data as inputs to existing climate modeling systems has direct societal implications ranging from improved prediction of energy demand to health assessment, but such data are lacking for most cities. To address this deficiency we have applied a standardized procedure to develop a national database of seasonally and diurnally varying anthropogenic heating profiles for 61 of the largest cities in the United Stated (U.S.). Recognizing the importance of spatial scale, the anthropogenic heating database developed includes the city scale and the accompanying greater metropolitan area. Our analysis reveals that a single profile function can adequately represent anthropogenic heating during summer but two profile functions are required in winter, one for warm climate cities and another for cold climate cities. On average, although anthropogenic heating is 40% larger in winter than summer, the electricity sector contribution peaks during summer and is smallest in winter. Because such data are similarly required for international cities where urban climate assessments are also ongoing, we have made a simple adjustment accounting for different international energy consumption rates relative to the U.S. to generate seasonally and diurnally varying anthropogenic heating profiles for a range of global cities. The methodological approach presented here is flexible and straightforwardly applicable to cities not modeled because of presently unavailable data. Because of the anticipated increase in global urban populations for many decades to come, characterizing this fundamental aspect of the urban environment - anthropogenic heating - is an essential

  11. Effect of low and high heating rates on reaction path of Ni(V)/Al multilayer

    Energy Technology Data Exchange (ETDEWEB)

    Maj, Łukasz, E-mail: l.maj@imim.pl [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta St., 30-059 Kraków (Poland); Morgiel, Jerzy; Szlezynger, Maciej [Institute of Metallurgy and Materials Science, Polish Academy of Sciences, 25 Reymonta St., 30-059 Kraków (Poland); Bała, Piotr; Cios, Grzegorz [AGH University of Science and Technology, Academic Centre for Materials and Nanotechnology, 30 Kawiory St., 30-055 Kraków (Poland)

    2017-06-01

    The effect of heating rates of Ni(V)/Al NanoFoils{sup ®} was investigated with transmission electron microscopy (TEM). The Ni(V)/Al were subjected to heating by using differential scanning calorimetry (DSC), in-situ TEM or electric pulse. Local chemical analysis was carried out using energy dispersive X-ray spectroscopy (EDS). Phase analysis was done with X-ray diffractions (XRD) and selected area electron diffractions (SAED). The experiments showed that slow heating in DSC results in development of separate exothermic effects at ∼230 °C, ∼280 °C and ∼390 °C, corresponding to precipitation of Al{sub 3}Ni, Al{sub 3}Ni{sub 2} and NiAl phases, respectively, i.e. like in vanadium free Ni/Al multilayers. Further heating to 700 °C allowed to obtain a single phase NiAl foil. The average grain size (g.s.) of NiAl phase produced in the DSC heat treated foil was comparable with the Ni(V)/Al multilayer period (∼50 nm), whereas in the case of reaction initiated with electric pulse the g.s. was in the micrometer range. Upon slow heating vanadium tends to segregate to zones parallel to the original multilayer internal interfaces, while in SHS process vanadium-rich phases precipitates at grain boundaries of the NiAl phase. - Highlights: • Peaks in DSC heating of Ni(V)/Al were explained by in-situ TEM observations. • Nucleation of Al{sub 3}Ni, Al{sub 3}Ni{sub 2} and NiAl at slow heating of Ni(V)/Al was documented. • Near surface NiAl obtained from NanoFoil show Ag precipitates at grain boundaries.

  12. Microwave heating device for internal heating convection experiments, applied to Earth's mantle dynamics.

    Science.gov (United States)

    Surducan, E; Surducan, V; Limare, A; Neamtu, C; Di Giuseppe, E

    2014-12-01

    We report the design, construction, and performances of a microwave (MW) heating device for laboratory experiments with non-contact, homogeneous internal heating. The device generates MW radiation at 2.47 GHz from a commercial magnetron supplied by a pulsed current inverter using proprietary, feedback based command and control hardware and software. Specially designed MW launchers direct the MW radiation into the sample through a MW homogenizer, devised to even the MW power distribution into the sample's volume. An adjustable MW circuit adapts the MW generator to the load (i.e., the sample) placed in the experiment chamber. Dedicated heatsinks maintain the MW circuits at constant temperature throughout the experiment. Openings for laser scanning for image acquisition with a CCD camera and for the cooling circuits are protected by special MW filters. The performances of the device are analyzed in terms of heating uniformity, long term output power stability, and load matching. The device is used for small scale experiments simulating Earth's mantle convection. The 30 × 30 × 5 cm(3) convection tank is filled with a water‑based viscous fluid. A uniform and constant temperature is maintained at the upper boundary by an aluminum heat exchanger and adiabatic conditions apply at the tank base. We characterize the geometry of the convective regime as well as its bulk thermal evolution by measuring the velocity field by Particle Image Velocimetry and the temperature field by using Thermochromic Liquid Crystals.

  13. Microwave heating device for internal heating convection experiments, applied to Earth's mantle dynamics

    Energy Technology Data Exchange (ETDEWEB)

    Surducan, E.; Surducan, V.; Neamtu, C., E-mail: camelia.neamtu@itim-cj.ro [National Institute for Research and Development of Isotopic and Molecular Technologies (INCDTIM), 67-103 Donat St., 400293, Cluj‑Napoca (Romania); Limare, A.; Di Giuseppe, E. [Institut de Physique du Globe de Paris (IPGP), Univ. Paris Diderot, UMR CNRS 7154, 1 rue Jussieu, 75005, Paris (France)

    2014-12-15

    We report the design, construction, and performances of a microwave (MW) heating device for laboratory experiments with non-contact, homogeneous internal heating. The device generates MW radiation at 2.47 GHz from a commercial magnetron supplied by a pulsed current inverter using proprietary, feedback based command and control hardware and software. Specially designed MW launchers direct the MW radiation into the sample through a MW homogenizer, devised to even the MW power distribution into the sample's volume. An adjustable MW circuit adapts the MW generator to the load (i.e., the sample) placed in the experiment chamber. Dedicated heatsinks maintain the MW circuits at constant temperature throughout the experiment. Openings for laser scanning for image acquisition with a CCD camera and for the cooling circuits are protected by special MW filters. The performances of the device are analyzed in terms of heating uniformity, long term output power stability, and load matching. The device is used for small scale experiments simulating Earth's mantle convection. The 30 × 30 × 5 cm{sup 3} convection tank is filled with a water‑based viscous fluid. A uniform and constant temperature is maintained at the upper boundary by an aluminum heat exchanger and adiabatic conditions apply at the tank base. We characterize the geometry of the convective regime as well as its bulk thermal evolution by measuring the velocity field by Particle Image Velocimetry and the temperature field by using Thermochromic Liquid Crystals.

  14. Devolatilization characteristics of biomass at flash heating rate

    Energy Technology Data Exchange (ETDEWEB)

    Xiu Shuangning; Li Zhihe; Li Baoming; Yi Weiming; Bai Xueyuan [China Agricultural University, Beijing (China). College of Water Conservancy and Civil Engineering

    2006-03-15

    The devolatilization characteristics of biomass (wheat straw, coconut shell, rice husk and cotton stalk) during flash pyrolysis has been investigated on a plasma heated laminar entrained flow reactor (PHLEFR) with average heating rates of 10{sup 4} K/s. These experiments were conducted with steady temperatures between 750 and 900 K, and the particle residence time varied from about 0.115 to 0.240 s. The ash tracer method was introduced to calculate the yield of volatile products at a set temperature and the residence time. This experimental study showed that the yield of volatile products depends both on the final pyrolysis temperature and the residence time. From the results, a comparative analysis was done for the biomasses, and a one-step global model was used to simulate the flash pyrolytic process and predict the yield of volatile products during pyrolysis. The corresponding kinetic parameters of the biomasses were also analyzed and determined. These results were essential for designing a suitable pyrolysis reactor. 24 refs., 5 figs., 5 tabs.

  15. A New Method to Calculate Internal Rate of Return

    Directory of Open Access Journals (Sweden)

    azadeh zandi

    2015-09-01

    Full Text Available A number of methods have been developed to choose the best capital investment projects such as net present value, internal rate of return and etc. Internal rate of return method is probably the most popular method among managers and investors. But despite the popularity there are serious drawbacks and limitations in this method. After decades of efforts made by economists and experts to improve the method and its shortcomings, Magni in 2010 has revealed a new approach that can solves the most of internal rate of return method problems. This paper present a new method which is originated from Magni’s approach but has much more simple calculations and can resolve all the drawbacks of internal rate of return method.

  16. Atmospheric solar heating rate in the water vapor bands

    Science.gov (United States)

    Chou, Ming-Dah

    1986-01-01

    The total absorption of solar radiation by water vapor in clear atmospheres is parameterized as a simple function of the scaled water vapor amount. For applications to cloudy and hazy atmospheres, the flux-weighted k-distribution functions are computed for individual absorption bands and for the total near-infrared region. The parameterization is based upon monochromatic calculations and follows essentially the scaling approximation of Chou and Arking, but the effect of temperature variation with height is taken into account in order to enhance the accuracy. Furthermore, the spectral range is extended to cover the two weak bands centered at 0.72 and 0.82 micron. Comparisons with monochromatic calculations show that the atmospheric heating rate and the surface radiation can be accurately computed from the parameterization. Comparisons are also made with other parameterizations. It is found that the absorption of solar radiation can be computed reasonably well using the Goody band model and the Curtis-Godson approximation.

  17. Nonlinear radiative heat flux and heat source/sink on entropy generation minimization rate

    Science.gov (United States)

    Hayat, T.; Khan, M. Waleed Ahmed; Khan, M. Ijaz; Alsaedi, A.

    2018-06-01

    Entropy generation minimization in nonlinear radiative mixed convective flow towards a variable thicked surface is addressed. Entropy generation for momentum and temperature is carried out. The source for this flow analysis is stretching velocity of sheet. Transformations are used to reduce system of partial differential equations into ordinary ones. Total entropy generation rate is determined. Series solutions for the zeroth and mth order deformation systems are computed. Domain of convergence for obtained solutions is identified. Velocity, temperature and concentration fields are plotted and interpreted. Entropy equation is studied through nonlinear mixed convection and radiative heat flux. Velocity and temperature gradients are discussed through graphs. Meaningful results are concluded in the final remarks.

  18. Investigations on a new internally-heated tubular packed-bed methanol–steam reformer

    KAUST Repository

    Nehe, Prashant

    2015-05-01

    Small-scale reformers for hydrogen production through steam reforming of methanol can provide an alternative solution to the demand of continuous supply of hydrogen gas for the operation of Proton Exchange Membrane Fuel Cells (PEMFCs). A packed-bed type reformer is one of the potential designs for such purpose. An externally heated reformer has issues of adverse lower temperature in the core of the reformer and significant heat loss to the environment thus impacting its performance. Experimental and numerical studies on a new concept of internally heated tubular packed-bed methanol-steam reformer have been reported in this paper with improved performance in terms of higher methanol conversion and reduced heat losses to surroundings. CuO/ZnO/Al2O3 is used as the catalyst for the methanol-steam reforming reaction and a rod-type electric heater at the center of the reactor is used for supplying necessary heat for endothermic steam reforming reaction. The vaporizer and the reformer unit with a constant volume catalyst bed are integrated in the annular section of a tubular reformer unit. The performance of the reformer was investigated at various operating conditions like feed rate of water-methanol mixture, mass of the catalyst and reforming temperature. The experimental and numerical results show that the methanol conversion and CO concentration increase with internal heating for a wide range of operating conditions. The developed reformer unit generates 50-80W (based on lower heating value) of hydrogen gas for applications in PEMFCs. For optimized design and operating conditions, the reformer unit produced 298sccm reformed gas containing 70% H2, 27% CO2 and 3% CO at 200-240°C which can produce a power output of 25-32W assuming 60% fuel cell efficiency and 80% of hydrogen utilization in a PEMFC. © 2015 Hydrogen Energy Publications, LLC.

  19. Memory behaviors of entropy production rates in heat conduction

    Science.gov (United States)

    Li, Shu-Nan; Cao, Bing-Yang

    2018-02-01

    Based on the relaxation time approximation and first-order expansion, memory behaviors in heat conduction are found between the macroscopic and Boltzmann-Gibbs-Shannon (BGS) entropy production rates with exponentially decaying memory kernels. In the frameworks of classical irreversible thermodynamics (CIT) and BGS statistical mechanics, the memory dependency on the integrated history is unidirectional, while for the extended irreversible thermodynamics (EIT) and BGS entropy production rates, the memory dependences are bidirectional and coexist with the linear terms. When macroscopic and microscopic relaxation times satisfy a specific relationship, the entropic memory dependences will be eliminated. There also exist initial effects in entropic memory behaviors, which decay exponentially. The second-order term are also discussed, which can be understood as the global non-equilibrium degree. The effects of the second-order term are consisted of three parts: memory dependency, initial value and linear term. The corresponding memory kernels are still exponential and the initial effects of the global non-equilibrium degree also decay exponentially.

  20. Are international fund flows related to exchange rate dynamics?

    NARCIS (Netherlands)

    Li, Suxiao; de Haan, Jakob; Scholtens, Bert

    2018-01-01

    Employing monthly data for 53 countries between 1996 and 2015, we investigate the relationship between international fund flows and exchange rate dynamics. We find strong co-movement between funds flows (as measured with the EPFR Global data base) and bilateral real exchange rates vis-à-vis the USD.

  1. Influence of short heat pulses on the helium boiling heat transfer rate

    International Nuclear Information System (INIS)

    Andreev, V.K.; Deev, V.I.; Savin, A.N.; Kutsenko, K.V.

    1987-01-01

    Investigation results on heat transfer in the process of helium boiling on a heated wall under conditions of pulsed heat effect are described. Results of the given study point to one of possible ways of heat exchange intensification in boiling helium by supplying short heat pulse to the heater. Even short-time noncontrolled or incidental increase in the heater capacity during experiment with boiling helium can result in a considerable disagreement of experimental data on heat transfer

  2. Exchange Rate Effects on International Commercial Trade Competitiveness

    Directory of Open Access Journals (Sweden)

    Ionel Bostan

    2018-04-01

    Full Text Available This study is meant to be an evaluation sustained by theoretical and empirical considerations of the exchange rate impact on international commercial trade competitiveness. In this respect, the study aims to find how the exchange rate influences Romanian competitiveness through assessing the effects generated on exports and imports. The main purpose of the study is to assess the complex action of the exchange rate on international commercial trade competitiveness in contemporaneity and the connections between these variables. The empirical part contains a regression analysis where exports and imports are dependent variables influenced by a series of determinants.

  3. Study on Gas-liquid Falling Film Flow in Internal Heat Integrated Distillation Column

    Science.gov (United States)

    Liu, Chong

    2017-10-01

    Gas-liquid internally heat integrated distillation column falling film flow with nonlinear characteristics, study on gas liquid falling film flow regulation control law, can reduce emissions of the distillation column, and it can improve the quality of products. According to the distribution of gas-liquid mass balance internally heat integrated distillation column independent region, distribution model of heat transfer coefficient of building internal heat integrated distillation tower is obtained liquid distillation falling film flow in the saturated vapour pressure of liquid water balance, using heat transfer equation and energy equation to balance the relationship between the circulating iterative gas-liquid falling film flow area, flow parameter information, at a given temperature, pressure conditions, gas-liquid flow falling film theory makes the optimal parameters to achieve the best fitting value with the measured values. The results show that the geometric gas-liquid internally heat integrated distillation column falling film flow heat exchange area and import column thermostat, the average temperature has significant. The positive correlation between the heat exchanger tube entrance due to temperature difference between inside and outside, the heat flux is larger, with the increase of internal heat integrated distillation column temperature, the slope decreases its temperature rise, which accurately describes the internal gas-liquid heat integrated distillation tower falling film flow regularity, take appropriate measures to promote the enhancement of heat transfer. It can enhance the overall efficiency of the heat exchanger.

  4. Research of Heating Rates Influence on Layer Coal Gasification of Krasnogorsky And Borodinsky Coal Deposit

    Directory of Open Access Journals (Sweden)

    Jankovskiy Stanislav

    2015-01-01

    Full Text Available Experimental research of heating rate influence on coal samples gasification process of Krasnogorsky and Borodinsky coal deposit ranks A and 2B was done to define optimal heating mode in high intensification of dispersal of inflammable gases conditions. Abundance ratio of carbon monoxide and nitrogen monoxide, water vapor, carbon dioxide at four values of heating rate within the range of 5 to 30 K/min. with further definition of optimal heating rate of coals was stated.

  5. The Influence of International Parity on the Exchange Rate: Purchasing Power Parity and International Fisher Effect

    OpenAIRE

    Oana Mionel

    2012-01-01

    This article assesses the impact of the inflation and interest rates on the exchange rates. The analysis tests the relation between the inflation rate and the exchange rate by applying the Purchasing Power Parity Theory, while the relation between the interest rate and the inflation rate is tested by applying the International Fisher Effect Theory. In order to test the Purchasing Power Parity the study takes into account the period of time between 1990 – 2009, and the following countries – th...

  6. Experimental investigation of natural convection induced by internal heat generation

    International Nuclear Information System (INIS)

    Tasaka, Y; Kudoh, Y; Takeda, Y; Yanagisawa, T

    2005-01-01

    Dilatation of a convection cell with respect to its Rayleigh number, one of the problems in internally heated convection, was quantitatively investigated by analyzing temperature field in a cell. The temperature field visualized by a thermo-chromic liquid crystal (TLC) expresses the cell dilatation. A calibration system was developed to convert the visualized photographs of the temperature field to the temperature field. A calibration curve correlating color information extracted from the photograph and temperature was determined from the approximately linear temperature distribution in the horizontal fluid layer using the hue method. Photos taken at various internal Rayleigh numbers were converted to the temperature field by the obtained curve. Extracting individual cells from a temperature field achieves a quantitative expression of the cell dilatation as the variation of the wavenumber of the cell with Rayleigh number increases. The temperature profile in a cell shows that high temperature areas appear at the apexes of the cell, largely different from the profile obtained by linear theory

  7. Heart rate variability during exertional heat stress: effects of heat production and treatment.

    Science.gov (United States)

    Flouris, Andreas D; Bravi, Andrea; Wright-Beatty, Heather E; Green, Geoffrey; Seely, Andrew J; Kenny, Glen P

    2014-04-01

    We assessed the efficacy of different treatments (i.e., treatment with ice water immersion vs. natural recovery) and the effect of exercise intensities (i.e., low vs. high) for restoring heart rate variability (HRV) indices during recovery from exertional heat stress (EHS). Nine healthy adults (26 ± 3 years, 174.2 ± 3.8 cm, 74.6 ± 4.3 kg, 17.9 ± 2.8 % body fat, 57 ± 2 mL·kg·(-1) min(-1) peak oxygen uptake) completed four EHS sessions incorporating either walking (4.0-4.5 km·h(-1), 2 % incline) or jogging (~7.0 km·h(-1), 2 % incline) on a treadmill in a hot-dry environment (40 °C, 20-30 % relative humidity) while wearing a non-permeable rain poncho for a slow or fast rate of rectal temperature (T re) increase, respectively. Upon reaching a T re of 39.5 °C, participants recovered until T re returned to 38 °C either passively or with whole-body immersion in 2 °C water. A comprehensive panel of 93 HRV measures were computed from the time, frequency, time-frequency, scale-invariant, entropy and non-linear domains. Exertional heat stress significantly affected 60/93 HRV measures analysed. Analyses during recovery demonstrated that there were no significant differences between HRV measures that had been influenced by EHS at the end of passive recovery vs. whole-body cooling treatment (p > 0.05). Nevertheless, the cooling treatment required statistically significantly less time to reduce T re (p whole-body immersion in 2 °C water results in faster cooling, there were no observed differences in restoration of autonomic heart rate modulation as measured by HRV indices with whole-body cold-water immersion compared to passive recovery in thermoneutral conditions.

  8. Dissolution and Precipitation Behaviour during Continuous Heating of Al–Mg–Si Alloys in a Wide Range of Heating Rates

    Science.gov (United States)

    Osten, Julia; Milkereit, Benjamin; Schick, Christoph; Kessler, Olaf

    2015-01-01

    In the present study, the dissolution and precipitation behaviour of four different aluminium alloys (EN AW-6005A, EN AW-6082, EN AW-6016, and EN AW-6181) in four different initial heat treatment conditions (T4, T6, overaged, and soft annealed) was investigated during heating in a wide dynamic range. Differential scanning calorimetry (DSC) was used to record heating curves between 20 and 600 °C. Heating rates were studied from 0.01 K/s to 5 K/s. We paid particular attention to control baseline stability, generating flat baselines and allowing accurate quantitative evaluation of the resulting DSC curves. As the heating rate increases, the individual dissolution and precipitation reactions shift to higher temperatures. The reactions during heating are significantly superimposed and partially run simultaneously. In addition, precipitation and dissolution reactions are increasingly suppressed as the heating rate increases, whereby exothermic precipitation reactions are suppressed earlier than endothermic dissolution reactions. Integrating the heating curves allowed the enthalpy levels of the different initial microstructural conditions to be quantified. Referring to time–temperature–austenitisation diagrams for steels, continuous heating dissolution diagrams for aluminium alloys were constructed to summarise the results in graphical form. These diagrams may support process optimisation in heat treatment shops.

  9. Dissolution and Precipitation Behaviour during Continuous Heating of Al–Mg–Si Alloys in a Wide Range of Heating Rates

    Directory of Open Access Journals (Sweden)

    Julia Osten

    2015-05-01

    Full Text Available In the present study, the dissolution and precipitation behaviour of four different aluminium alloys (EN AW-6005A, EN AW-6082, EN AW-6016, and EN AW-6181 in four different initial heat treatment conditions (T4, T6, overaged, and soft annealed was investigated during heating in a wide dynamic range. Differential scanning calorimetry (DSC was used to record heating curves between 20 and 600 °C. Heating rates were studied from 0.01 K/s to 5 K/s. We paid particular attention to control baseline stability, generating flat baselines and allowing accurate quantitative evaluation of the resulting DSC curves. As the heating rate increases, the individual dissolution and precipitation reactions shift to higher temperatures. The reactions during heating are significantly superimposed and partially run simultaneously. In addition, precipitation and dissolution reactions are increasingly suppressed as the heating rate increases, whereby exothermic precipitation reactions are suppressed earlier than endothermic dissolution reactions. Integrating the heating curves allowed the enthalpy levels of the different initial microstructural conditions to be quantified. Referring to time–temperature–austenitisation diagrams for steels, continuous heating dissolution diagrams for aluminium alloys were constructed to summarise the results in graphical form. These diagrams may support process optimisation in heat treatment shops.

  10. Forsmark - System 522. Recursive linear regression for the determination of heating rate

    International Nuclear Information System (INIS)

    Carlsson, B.

    1980-01-01

    The heating rate for reactor tank and steam tubes is limited. The algorithm of the heating rate has been implemented on the computer and compared with real data from Forsmark-2. The evaluation of data shows a considerable improvement of the determination of derivata which contributes to information during heating events. (G.B.)

  11. A Study of the Mechanical Behavior of OFHC Copper in Tension at Various Strain Rates and Heating Rates Using the Two-Dimensional Integrated Speckle Measuring System

    National Research Council Canada - National Science Library

    Durant, Brian

    2000-01-01

    .... A modified dog bone specimen was heated using resistive heating techniques. The effects of high temperature, medium strain rates, and high heating rates on the stress-strain results were observed...

  12. Dynamic response of a system with internal heat sources cooled by a flowing incompressible fluid

    International Nuclear Information System (INIS)

    Georgescu, R.; Dobrescu, C.

    1975-01-01

    The paper investigates the dynamic temperature response of an incompressible fluid which cools a duct with internal heat sources sinusoidally oscillated. The analytical results utilise the Laplace transformation technique. The experimental and calculated results are obtained by transfer function approach. Comparison of the calculated with the experimental data indicates agreement from 6 to 24 percent for the amplitude and up to 30 degree for the phase-shift. All the calculated data are below the experimental ones. The analytical method of transfer function approach presents interest and may be utilized for the initial calculations giving good results for flow rates above 1000 kg per hour

  13. Autonomic responses to heat pain: Heart rate, skin conductance, and their relation to verbal ratings and stimulus intensity.

    Science.gov (United States)

    Loggia, Marco L; Juneau, Mylène; Bushnell, M Catherine

    2011-03-01

    In human pain experiments, as well as in clinical settings, subjects are often asked to assess pain using scales (eg, numeric rating scales). Although most subjects have little difficulty in using these tools, some lack the necessary basic cognitive or motor skills (eg, paralyzed patients). Thus, the identification of appropriate nonverbal measures of pain has significant clinical relevance. In this study, we assessed heart rate (HR), skin conductance (SC), and verbal ratings in 39 healthy male subjects during the application of twelve 6-s heat stimuli of different intensities on the subjects' left forearm. Both HR and SC increased with more intense painful stimulation. However, HR but not SC, significantly correlated with pain ratings at the group level, suggesting that HR may be a better predictor of between-subject differences in pain than is SC. Conversely, changes in SC better predicted variations in ratings within a given individual, suggesting that it is more sensitive to relative changes in perception. The differences in findings derived from between- and within-subject analyses may result from greater within-subject variability in HR. We conclude that at least for male subjects, HR provides a better predictor of pain perception than SC, but that data should be averaged over several stimulus presentations to achieve consistent results. Nevertheless, variability among studies, and the indication that gender of both the subject and experimenter could influence autonomic results, lead us to advise caution in using autonomic or any other surrogate measures to infer pain in individuals who cannot adequately report their perception. Skin conductance is more sensitive to detect within-subject perceptual changes, but heart rate appears to better predict pain ratings at the group level. Copyright © 2010 International Association for the Study of Pain. Published by Elsevier B.V. All rights reserved.

  14. Heat transfer characteristics for evaporation of R417A flowing inside horizontal smooth and internally grooved tubes

    Energy Technology Data Exchange (ETDEWEB)

    Xiaoyan, Zhang [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China); School of Energy Engineering, Xi' an University of Science and Technology, 58 Yanta Street, Xi' an, Shaanxi 710054 (China)], E-mail: gqzxy@sohu.com; Xingqun, Zhang; Yunguang, Chen; Xiuling, Yuan [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China)

    2008-06-15

    The experimental study on evaporation heat transfer of R417A (R125/R134a/R600) flowing inside horizontal smooth and two internally grooved tubes with different geometrical parameters was conducted with the mass flow rate range from 176 to 344 kg m{sup -2} s{sup -1}, heat flux from 11 to 32 kW m{sup -2}, evaporation temperature from 0 to 5.5 deg. C and vapor quality from 0.2 to 1. Based on the experimental results, the mechanism and role of the mass flow rate, heat flux, vapor quality and enhanced surface influencing the evaporation heat transfer coefficients were analyzed and discussed. In comparison to R22, the evaporation heat transfer coefficients for R417A were lower and much lower in the internally grooved tubes than in the smooth tube. The present experimental results are also compared with the existing correlations, and the modified Kattan model is found to be in much better agreement with the experimental results than the Kattan model. The Koyama and Wellsandt microfin models all tend to over predict the evaporation heat transfer coefficients rather strongly for R417A inside internally grooved tubes.

  15. Heat transfer characteristics for evaporation of R417A flowing inside horizontal smooth and internally grooved tubes

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Xiaoyan [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China); School of Energy Engineering, Xi' an University of Science and Technology, 58 Yanta Street, Xi' an, Shaanxi 710054 (China); Zhang, Xingqun; Chen, Yunguang; Yuan, Xiuling [School of Energy and Power Engineering, Xi' an Jiaotong University, 28 Xianning Road, Xi' an, Shaanxi 710049 (China)

    2008-06-15

    The experimental study on evaporation heat transfer of R417A (R125/R134a/R600) flowing inside horizontal smooth and two internally grooved tubes with different geometrical parameters was conducted with the mass flow rate range from 176 to 344 kg m{sup -2} s{sup -1}, heat flux from 11 to 32 kW m{sup -2}, evaporation temperature from 0 to 5.5{sup o}C and vapor quality from 0.2 to 1. Based on the experimental results, the mechanism and role of the mass flow rate, heat flux, vapor quality and enhanced surface influencing the evaporation heat transfer coefficients were analyzed and discussed. In comparison to R22, the evaporation heat transfer coefficients for R417A were lower and much lower in the internally grooved tubes than in the smooth tube. The present experimental results are also compared with the existing correlations, and the modified Kattan model is found to be in much better agreement with the experimental results than the Kattan model. The Koyama and Wellsandt microfin models all tend to over predict the evaporation heat transfer coefficients rather strongly for R417A inside internally grooved tubes. (author)

  16. Heat transfer characteristics for evaporation of R417A flowing inside horizontal smooth and internally grooved tubes

    International Nuclear Information System (INIS)

    Zhang Xiaoyan; Zhang Xingqun; Chen Yunguang; Yuan Xiuling

    2008-01-01

    The experimental study on evaporation heat transfer of R417A (R125/R134a/R600) flowing inside horizontal smooth and two internally grooved tubes with different geometrical parameters was conducted with the mass flow rate range from 176 to 344 kg m -2 s -1 , heat flux from 11 to 32 kW m -2 , evaporation temperature from 0 to 5.5 deg. C and vapor quality from 0.2 to 1. Based on the experimental results, the mechanism and role of the mass flow rate, heat flux, vapor quality and enhanced surface influencing the evaporation heat transfer coefficients were analyzed and discussed. In comparison to R22, the evaporation heat transfer coefficients for R417A were lower and much lower in the internally grooved tubes than in the smooth tube. The present experimental results are also compared with the existing correlations, and the modified Kattan model is found to be in much better agreement with the experimental results than the Kattan model. The Koyama and Wellsandt microfin models all tend to over predict the evaporation heat transfer coefficients rather strongly for R417A inside internally grooved tubes

  17. Internally heated mantle convection and the thermal and degassing history of the earth

    Science.gov (United States)

    Williams, David R.; Pan, Vivian

    1992-01-01

    An internally heated model of parameterized whole mantle convection with viscosity dependent on temperature and volatile content is examined. The model is run for 4l6 Gyr, and temperature, heat flow, degassing and regassing rates, stress, and viscosity are calculated. A nominal case is established which shows good agreement with accepted mantle values. The effects of changing various parameters are also tested. All cases show rapid cooling early in the planet's history and strong self-regulation of viscosity due to the temperature and volatile-content dependence. The effects of weakly stress-dependent viscosity are examined within the bounds of this model and are found to be small. Mantle water is typically outgassed rapidly to reach an equilibrium concentration on a time scale of less than 200 Myr for almost all models, the main exception being for models which start out with temperatures well below the melting temperature.

  18. A study of the rates of heat transfer and bubble site density for nucleate boiling on an inclined heating surface

    International Nuclear Information System (INIS)

    Bonamy, S.E.; Symons, J.G.

    1974-08-01

    Nucleate pool boiling of distilled water from an electrically heated surface at atmospheric pressure is studied for varying heating surface inclinations. The constants of the accepted boiling equation phi = K Tsup(B) and the Rohsenow Correlation Coefficient are found to be dependent on surface orientation. Convection cooling is observed to play a major role in pool boiling phenomena and causes large changes in the heat transfer rates for a given excess of temperature of the heated surface. Active nucleation site density is studied and found to be independent of surface inclination. Empirical relations are presented to provide an understanding of the effects of inclination on other boiling parameters. (author)

  19. Exchange Rate and International Trade: Case From Indonesian Manufacturing Sector

    Directory of Open Access Journals (Sweden)

    Anung Yoga Anindhita

    2017-07-01

    Full Text Available Exchange rate fluctuation in Floating Exchange Rate Regime is considered to Exchange rate fluctuation in Floating Exchange Rate Regime is considered to have impacts on the international trade through its adjustment to the price and its volatility to the trade risk. This paper is aimed at estimating those impacts on the international trade of manufacturing sector in Indonesia for period 2007 to 2014. To conduct estimation, it uses multiple regression analysis on two models: First, the import of raw-and-auxiliary materials; Second, the export of manufacturing sector. The results show that the exchange rate impacts both work significantly on the import of raw-and-auxiliary materials. The finding implies that, through the import of raw-and-auxiliary materials, manufacturing sector is very susceptible to the shock caused by exchange rate changes. Meanwhile, the export of manufacturing sector is not able to take advantage of the depreciation of the exchange rate due to the lack of competitiveness.DOI: 10.15408/sjie.v6i2.5210

  20. Determination of Factors Related to Students' Understandings of Heat, Temperature and Internal Energy Concepts

    Science.gov (United States)

    Gurcay, Deniz; Gulbas, Etna

    2018-01-01

    The purpose of this research is to investigate the relationships between high school students' learning approaches and logical thinking abilities and their understandings of heat, temperature and internal energy concepts. Learning Approach Questionnaire, Test of Logical Thinking and Three-Tier Heat, Temperature and Internal Energy Test were used…

  1. THE IMPLICATIONS OF VARYING EXCHANGE RATES FOR THE INTERNATIONAL TRADE

    Directory of Open Access Journals (Sweden)

    Sandu Carmen

    2011-07-01

    Full Text Available The benefit of international trade is a more efficient employment of the productive forces of the world. (John Stuart Mill The exchange rate is a primary factor that influences economy. This instrument is used by some countries in order to improve the lack of balance caused as a result of the financial crisis felt in many countries considered by then infallible. The negative effects of the financial crisis can also be found in the decreased volume of commodities involved in international trade exchanges, as a consequence of modified prices and decreased offer. The globalizing trend leads to a constant expansion of exchanges between countries and to the consolidation of international cooperation. Except that economic interdependence generates an increased risk under the influence of economic, financial, monetary or political factors. The currency risk can generate either a gain or loss during foreign trade operations. The long period of RON depreciation made possible the entry of Romanian products on the international markets due to their prices. Sheltered by the gain generated by the evolution of the exchange rate, most of the exporters were not concerned by the increase of product competitiveness or by avoiding the currency risk. The fact that, for many years, the evolution of the exchange rate generated substantial losses for the exporters shows that risk coverage in Romania is, in most cases, a purely theoretical concept.

  2. Manipulating the discount rate when valuing international investment projects

    Directory of Open Access Journals (Sweden)

    A. A. Medved

    2017-01-01

    Full Text Available The article deals with the practice of evaluation of international investment projects using the cash flow discounting rate. The problem of the discount rate manipulating is connected with the category “country risk”, which often determines the impact on the rate and, accordingly, the investment decisions. Critically examines existing approaches to the definition of “country risk”. Categories that make up a complete picture of “country risk” are distinguished. The general defect of existing country risk concepts is revealed – the fact that the measurements are based on rather subjective assessments and do not have sufficient empirical evidence, the fact that almost all of them have a clear liberal democratic bias: as a rule, drawing attention to the relationship between the political system and stability, the liberal democratic structure of society is recognized as the most stable, without any acceptable scientific evidence, followed by autocracy, military dictatorships and new independent states. The author affirms the lack of a clear and unambiguous definition of this category, the controversial approach to ranking of countries. The author analyzes and proves the bias of rating assigned by foreign companies. As a conclusion the need to create a national research concept of the “country risk” category is аffirms with the subsequent promotion of national rating agencies to the world market. The author's conception of the category “country risk” is proposed, an author's definition is given to this notion, it is recommended to establish the primacy of national ratings over foreign ones both in domestic and international relations in order to have independent influence on international capital flows. It is also proposed the evaluation of projects based on the dynamic discounting rates, especially for long-term strategic projects.

  3. Influence of heating rate on corrosion behavior of Ni-base heat resistant alloys in simulated VHTR helium environment

    International Nuclear Information System (INIS)

    Kurata, Yuji; Kondo, Tatsuo

    1985-04-01

    The influence of heating rate on corrosion and carbon transfer was studied for Ni-base heat resistant alloys exposed to simulated VHTR(very high temperature reactor) coolant environment. Special attention was focused to relationship between oxidation and carburization at early stage of exposure. Tests were conducted on two heats of Hastelloy XR with different boron(B) content and the developmental alloys, 113MA and KSN. Two kinds of heating rates, i.e. 80 0 C/min and 2 0 C/min, were employed. Corrosion tests were carried out at 900 0 C up to 500 h in JAERI Type B helium, one of the simulated VHTR primary coolant specifications. Under higher heating rate, oxidation resistance of both heats of Hastelloy XR(2.8 ppmB and 40 ppmB) were equivalent and among the best, then KSN and 113MA followed in the order. Under lower heating rate only alloy, i.e. Hastelloy XR with 2.8 ppmB, showed some deteriorated oxidation resistance while all others being unaffected by the heating rate. On the other hand the carbon transfer behavior showed strong dependence on the heating rate. In case of higher heating rate, significant carburization occured at early stage of exposure and thereafter the progress of carburization was slow in all the alloys. On the other hand only slow carburization was the case throughout the exposure in case of lower heating rate. The carburization in VHTR helium environment was interpreted as to be affected by oxide film formation in the early stage of exposure. The carbon pick-up was largest in Hastelloy XR with 40 ppmB and it was followed by Hastelloy XR with 2.8 ppmB. 113MA and KSN were carburized only slightly. The observed difference of carbon pick-up among the alloys tested was interpreted to be attributed mainly to the difference of the carbon activity, the carbide precipitation characteristics among the alloys tested. (author)

  4. Formation of H{sub 2} from internally heated polycyclic aromatic hydrocarbons: Excitation energy dependence

    Energy Technology Data Exchange (ETDEWEB)

    Chen, T., E-mail: tao.chen@fysik.su.se, E-mail: henning@fysik.su.se; Gatchell, M.; Stockett, M. H.; Schmidt, H. T.; Cederquist, H.; Zettergren, H., E-mail: tao.chen@fysik.su.se, E-mail: henning@fysik.su.se [Department of Physics, Stockholm University, S-106 91 Stockholm (Sweden); Delaunay, R.; Rousseau, P.; Adoui, L. [CIMAP, UMR 6252, CEA/CNRS/ENSICAEN/Université de Caen Basse-Normandie, bd Henri Becquerel, BP 5133, F-14070 Caen cedex 05 (France); Université de Caen Basse-Normandie, Esplanade de la Paix, F-14032 Caen (France); Domaracka, A.; Huber, B. A. [CIMAP, UMR 6252, CEA/CNRS/ENSICAEN/Université de Caen Basse-Normandie, bd Henri Becquerel, BP 5133, F-14070 Caen cedex 05 (France); Micelotta, E. R. [Université Paris Sud, Institut d’Astrophysique Spatiale, UMR 8617, 91405 Orsay (France); Tielens, A. G. G. M. [Leiden Observatory, Leiden University, P.O. Box 9513, 2300 RA Leiden (Netherlands)

    2015-04-14

    We have investigated the effectiveness of molecular hydrogen (H{sub 2}) formation from Polycyclic Aromatic Hydrocarbons (PAHs) which are internally heated by collisions with keV ions. The present and earlier experimental results are analyzed in view of molecular structure calculations and a simple collision model. We estimate that H{sub 2} formation becomes important for internal PAH temperatures exceeding about 2200 K, regardless of the PAH size and the excitation agent. This suggests that keV ions may effectively induce such reactions, while they are unlikely due to, e.g., absorption of single photons with energies below the Lyman limit. The present analysis also suggests that H{sub 2} emission is correlated with multi-fragmentation processes, which means that the [PAH-2H]{sup +} peak intensities in the mass spectra may not be used for estimating H{sub 2}-formation rates.

  5. The Influence of International Parity on the Exchange Rate: Purchasing Power Parity and International Fisher Effect

    Directory of Open Access Journals (Sweden)

    Oana Mionel

    2012-02-01

    Full Text Available This article assesses the impact of the inflationand interest rates on the exchange rates.The analysis tests the relation between the inflation rate and the exchange rate by applying thePurchasing Power Parity Theory, while the relationbetween the interest rate and the inflation rate istested by applying the International Fisher EffectTheory. In order to test the Purchasing Power Paritythe study takes into account the period of time between 1990 – 2009, and the following countries –the USA, Germany, the UK, Switzerland, Canada, Japan and China. As for testing the InternationalFisher Effect Theory the period of time is the same, 1990 – 2009, but a few countries are different –the USA, Germany, the UK, Switzerland, Canada, Australia and New Zeeland. Thus, both theoriesanalyse the USA as home country.

  6. Thermodynamic analysis of an in-cylinder waste heat recovery system for internal combustion engines

    International Nuclear Information System (INIS)

    Zhu, Sipeng; Deng, Kangyao; Qu, Shuan

    2014-01-01

    In this paper, an in-cylinder waste heat recovery system especially for turbocharged engines is proposed to improve the thermal efficiencies of internal combustion engines. Simplified recovery processes can be described as follows: superheated steam generated by engine waste heat is injected into the pipe before the turbine to increase the boost pressure of the fresh air; intake valve close timing is adjusted to control the amount of fresh air as the original level, and thus the higher pressure charged air expands in the intake stroke and transfers the pressure energy directly to the crankshaft. In this way, the increased turbine output by the pre-turbine steam injection is finally recovered in the cylinder, which is different from the traditional Rankine cycle. The whole energy transfer processes are studied with thermodynamic analyses and numerical simulations. The results show that the mass flow rate of the injected steam has the biggest influence on the energy transfer processes followed by the temperature of the injected steam. With this in-cylinder waste heat recovery system, the fuel economy of a selected turbocharged diesel engine can be improved by 3.2% at the rated operating point when the injected mass flow ratio is set to be 0.1. - Highlights: • An in-cylinder waste heat recovery system is proposed. • Effects of injected parameters are studied with energy and exergy balance theories. • Variations of operating points on the compressor map are studied in detail. • The fuel economy is improved by 3.2% at the rated operating point

  7. Gravity influence on heat transfer rate in flow boiling

    NARCIS (Netherlands)

    Baltis, C.H.M.; Celata, G.P.; Cumo, M.; Saraceno, L.; Zummo, G.

    2012-01-01

    The aim of the present paper is to describe the results of flow boiling heat transfer at low gravity and compare them with those obtained at earth gravity, evaluating possible differences. The experimental campaigns at low gravity have been performed with parabolic flights. The paper will show the

  8. Heat generation rates in lithium thionyl chloride cells

    Science.gov (United States)

    Frank, H.

    1982-03-01

    An empirical equation that is useful for good first approximation in thermal modeling is presented. Indications and measurements of electrochemical heat effects were investigated. The particular cells of interest are of the D size, with spiral wound configuration and were instrumented with a thermocouple. It is found that cathode limited cells can explode on reversal at moderate temperatures.

  9. Molecular investigations on grain filling rate under terminal heat ...

    African Journals Online (AJOL)

    Ezedom Theresa

    2013-07-10

    Jul 10, 2013 ... under terminal heat stress in bread wheat. (Triticum aestivum L.) Girish Chandra Pandey1, Jagadish ... ficantly in all the bread and durum wheat genotypes, because of significant interaction of each ..... wheat varieties and registered genetic stocks (Triticum L.). Technical. Bulletin No.13, Directorate of Wheat ...

  10. Heat transfer in composite materials disintegrating under high-rate one-sided heating

    Science.gov (United States)

    Isaev, K. B.

    1993-12-01

    A mathematical model of heat transfer in heat-protective materials is suggested with the proviso of a squarelaw temperature depence of the material density in the zone of thermal destruction of its binder. The influence of certain factors on the experimental temperature field and thermal conductivity of a glass-reinforced epoxy plastic material is shown.

  11. Homotopy Perturbation Method for Thin Film Flow and Heat Transfer over an Unsteady Stretching Sheet with Internal Heating and Variable Heat Flux

    Directory of Open Access Journals (Sweden)

    I-Chung Liu

    2012-01-01

    Full Text Available We have analyzed the effects of variable heat flux and internal heat generation on the flow and heat transfer in a thin film on a horizontal sheet in the presence of thermal radiation. Similarity transformations are used to transform the governing equations to a set of coupled nonlinear ordinary differential equations. The obtained differential equations are solved approximately by the homotopy perturbation method (HPM. The effects of various parameters governing the flow and heat transfer in this study are discussed and presented graphically. Comparison of numerical results is made with the earlier published results under limiting cases.

  12. Critical heat flux and exit film flow rate in a flow boiling system

    International Nuclear Information System (INIS)

    Ueda, Tatsuhiro; Isayama, Yasushi

    1981-01-01

    The critical heat flux in a flowing boiling system is an important problem in the evaporating tubes with high thermal load such as nuclear reactors and boilers, and gives the practical design limit. When the heat flux in uniformly heated evaporating tubes is gradually raised, the tube exit quality increases, and soon, the critical heat flux condition arises, and the wall temperature near tube exit rises rapidly. In the region of low exit quality, the critical heat flux condition is caused by the transition from nucleating boiling, and in the region of high exit quality, it is caused by dry-out. But the demarcation of both regions is not clear. In this study, for the purpose of obtaining the knowledge concerning the critical heat flux condition in a flowing boiling system, the relation between the critical heat flux and exit liquid film flow rate was examined. For the experiment, a uniformly heated vertical tube supplying R 113 liquid was used, and the measurement in the range of higher heating flux and mass velocity than the experiment by Ueda and Kin was carried out. The experimental setup and experimental method, the critical heat flux and exit quality, the liquid film flow rate at heating zone exit, and the relation between the critical heat flux and the liquid film flow rate at exit are described. (Kako, I.)

  13. ANALYSIS OF MEASURES FOR INCREASING THE RATING OF UNIVERSITY IN INTERNATIONAL RATING SYSTEM

    Directory of Open Access Journals (Sweden)

    В.П. Харченко

    2011-02-01

    Full Text Available The principles of forming the world's most popular international Internet-ranking of universities are considered. The principles of forming the international rating of electronic resources known as Webometrics, which results are defined by summing four values based on quantity of unique external links to the site page and by the quantity of “valuable” files placed on website are represented.  Мost Internet ratings make slope on the  Web activity of the university and its researchers, therefore the participation of entire staff at university is required

  14. Effect of rotational speed modulation on heat transport in a fluid layer with temperature dependent viscosity and internal heat source

    Directory of Open Access Journals (Sweden)

    B.S. Bhadauria

    2014-12-01

    Full Text Available In this paper, a theoretical investigation has been carried out to study the combined effect of rotation speed modulation and internal heating on thermal instability in a temperature dependent viscous horizontal fluid layer. Rayleigh–Bénard momentum equation with Coriolis term has been considered to describe the convective flow. The system is rotating about it is own axis with non-uniform rotational speed. In particular, a time-periodic and sinusoidally varying rotational speed has been considered. A weak nonlinear stability analysis is performed to find the effect of modulation on heat transport. Nusselt number is obtained in terms of amplitude of convection and internal Rayleigh number, and depicted graphically for showing the effects of various parameters of the system. The effect of modulated rotation speed is found to have a stabilizing effect for different values of modulation frequency. Further, internal heating and thermo-rheological parameters are found to destabilize the system.

  15. On oscillatory magnetoconvection in a nanofluid layer in the presence of internal heat source and Soret effect

    Science.gov (United States)

    Khalid, Izzati Khalidah; Mokhtar, Nor Fadzillah Mohd; Bakri, Nur Amirah; Siri, Zailan; Ibrahim, Zarina Bibi; Gani, Siti Salwa Abd

    2017-11-01

    The onset of oscillatory magnetoconvection for an infinite horizontal nanofluid layer subjected to Soret effect and internal heat source heated from below is examined theoretically with the implementation of linear stability theory. Two important properties that are thermophoresis and Brownian motion are included in the model and three types of lower-upper bounding systems of the model: rigid-rigid, rigid-free as well as free-free boundaries are examined. Eigenvalue equations are gained from a normal mode analysis and executed using Galerkin technique. Magnetic field effect, internal heat source effect, Soret effect and other nanofluid parameters on the oscillatory convection are presented graphically. For oscillatory mode, it is found that the effect of internal heat source is quite significant for small values of the non-dimensional parameter and elevating the internal heat source speed up the onset of convection. Meanwhile, the increasing of the strength of magnetic field in a nanofluid layer reduced the rate of thermal instability and sustain the stabilization of the system. For the Soret effect, the onset of convection in the system is accelerated when the values of the Soret effect is increased.

  16. Convective Heat Transfer Scaling of Ignition Delay and Burning Rate with Heat Flux and Stretch Rate in the Equivalent Low Stretch Apparatus

    Science.gov (United States)

    Olson, Sandra

    2011-01-01

    To better evaluate the buoyant contributions to the convective cooling (or heating) inherent in normal-gravity material flammability test methods, we derive a convective heat transfer correlation that can be used to account for the forced convective stretch effects on the net radiant heat flux for both ignition delay time and burning rate. The Equivalent Low Stretch Apparatus (ELSA) uses an inverted cone heater to minimize buoyant effects while at the same time providing a forced stagnation flow on the sample, which ignites and burns as a ceiling fire. Ignition delay and burning rate data is correlated with incident heat flux and convective heat transfer and compared to results from other test methods and fuel geometries using similarity to determine the equivalent stretch rates and thus convective cooling (or heating) rates for those geometries. With this correlation methodology, buoyant effects inherent in normal gravity material flammability test methods can be estimated, to better apply the test results to low stretch environments relevant to spacecraft material selection.

  17. Numerical Investigation of Turbulent Natural Convection Heat Transfer in an Internally-Heated Melt Pool and Metallic Layer

    International Nuclear Information System (INIS)

    Nourgaliev, R.R.; Dinh, A.T.; Dinh, T.N.; Sehgal, B.R.

    1999-01-01

    This paper presents results of numerical investigation of turbulent natural convection in an internally-heated oxidic pool, and in a metallic layer heated from below and cooled from top and sidewalls. Emphasis is placed upon applicability of the existing heat transfer correlations (obtained from simulant-material experiments) in assessments of a prototypic severe reactor accident. The objectives of this study are (i) to improve the current understanding of the physics of unstably stratified flows, and (ii) to reduce uncertainties associated with modeling and assessment of natural convection heat transfer in the above configuration. Prediction capabilities of different turbulence modeling approaches are first examined and discussed, based on extensive results of numerical investigations performed by present authors. Findings from numerical modeling of turbulent natural convection flow and heat transfer in melt pools and metallic layers are then described. (authors)

  18. Calorimeter measures high nuclear heating rates and their gradients across a reactor test hole

    Science.gov (United States)

    Burwell, D.; Coombe, J. R.; Mc Bride, J.

    1970-01-01

    Pedestal-type calorimeter measures gamma-ray heating rates from 0.5 to 7.0 watts per gram of aluminum. Nuclear heating rate is a function of cylinder temperature change, measured by four chromel-alumel thermocouples attached to the calorimeter, and known thermoconductivity of the tested material.

  19. Estimation of Surface Temperature and Heat Flux by Inverse Heat Transfer Methods Using Internal Temperatures Measured While Radiantly Heating a Carbon/Carbon Specimen up to 1920 F

    Science.gov (United States)

    Pizzo, Michelle; Daryabeigi, Kamran; Glass, David

    2015-01-01

    The ability to solve the heat conduction equation is needed when designing materials to be used on vehicles exposed to extremely high temperatures; e.g. vehicles used for atmospheric entry or hypersonic flight. When using test and flight data, computational methods such as finite difference schemes may be used to solve for both the direct heat conduction problem, i.e., solving between internal temperature measurements, and the inverse heat conduction problem, i.e., using the direct solution to march forward in space to the surface of the material to estimate both surface temperature and heat flux. The completed research first discusses the methods used in developing a computational code to solve both the direct and inverse heat transfer problems using one dimensional, centered, implicit finite volume schemes and one dimensional, centered, explicit space marching techniques. The developed code assumed the boundary conditions to be specified time varying temperatures and also considered temperature dependent thermal properties. The completed research then discusses the results of analyzing temperature data measured while radiantly heating a carbon/carbon specimen up to 1920 F. The temperature was measured using thermocouple (TC) plugs (small carbon/carbon material specimens) with four embedded TC plugs inserted into the larger carbon/carbon specimen. The purpose of analyzing the test data was to estimate the surface heat flux and temperature values from the internal temperature measurements using direct and inverse heat transfer methods, thus aiding in the thermal and structural design and analysis of high temperature vehicles.

  20. Selective Internal Heat Distribution in Modified Trombe Wall

    Science.gov (United States)

    Szyszka, Jerzy; Kogut, Janusz; Skrzypczak, Izabela; Kokoszka, Wanda

    2017-12-01

    At present, the requirements for thermal insulation of the external walls in buildings are being increased. There is a need to reduce energy consumption for heating rooms during the winter season. This may be achieved by increasing the thermal resistance of the outer partitions, using solutions that utilize either recuperation or solar radiation. The most popular systems include either solar collectors, or heat pump links or ground exchangers. Trombe walls (TW) are a very promising passive heating system, which requires little or no effort to operate, and may be very convenient in different climate conditions. A typical TW consists of a masonry wall painted a dark, heat absorbing paint colour and faced with a single or double layer of glass. The principle of operation is based on the photothermal conversion of solar radiation. There are various modifications of TW. They may improve the energy efficiency in relation to the climate conditions in which they operate. The hybrid solutions are also known. The efficiency of walls is related to the use of proper materials. In TW, the compromise should be sought between the thermal resistance and the ability to distribute heat from the absorbed energy of solar radiation. The paper presents an overview of the most commonly used solutions and discusses its own concept dedicated to the climate conditions of Central Europe.

  1. Estimate of the global-scale joule heating rates in the thermosphere due to time mean currents

    International Nuclear Information System (INIS)

    Roble, R.G.; Matsushita, S.

    1975-01-01

    An estimate of the global-scale joule heating rates in the thermosphere is made based on derived global equivalent overhead electric current systems in the dynamo region during geomagnetically quiet and disturbed periods. The equivalent total electric field distribution is calculated from Ohm's law. The global-scale joule heating rates are calculated for various monthly average periods in 1965. The calculated joule heating rates maximize at high latitudes in the early evening and postmidnight sectors. During geomagnetically quiet times the daytime joule heating rates are considerably lower than heating by solar EUV radiation. However, during geomagnetically disturbed periods the estimated joule heating rates increase by an order of magnitude and can locally exceed the solar EUV heating rates. The results show that joule heating is an important and at times the dominant energy source at high latitudes. However, the global mean joule heating rates calculated near solar minimum are generally small compared to the global mean solar EUV heating rates. (auth)

  2. Non-equilibrium effects of core-cooling and time-dependent internal heating on mantle flush events

    Directory of Open Access Journals (Sweden)

    D. A. Yuen

    1995-01-01

    Full Text Available We have examined the non-equilibrium effects of core-cooling and time-dependent internal-heating on the thermal evolution of the Earth's mantle and on mantle flush events caused by the two major phase transitions. Both two- and three-dimensional models have been employed. The mantle viscosity responds to the secular cooling through changes in the averaged temperature field. A viscosity which decreases algebraically with the average temperature has been considered. The time-dependent internal-heating is prescribed to decrease exponentially with a single decay time. We have studied the thermal histories with initial Rayleigh numbers between 2 x 107 and 108 . Flush events, driven by the non-equilibrium forcings, are much more dramatic than those produced by the equilibrium boundary conditions and constant internal heating. Multiple flush events are found under non-equilibrium conditions in which there is very little internal heating or very fast decay rates of internal-heating. Otherwise, the flush events take place in a relatively continuous fashion. Prior to massive flush events small-scale percolative structures appear in the 3D temperature fields. Time-dependent signatures, such as the surface heat flux, also exhibits high frequency oscillatory patterns prior to massive flush events. These two observations suggest that the flush event may be a self-organized critical phenomenon. The Nusselt number as a function of the time-varying Ra does not follow the Nusselt vs. Rayleigh number power-law relationship based on equilibrium (constant temperature boundary conditions. Instead Nu(t may vary non-monotonically with time because of the mantle flush events. Convective processes in the mantle operate quite differently under non-equilibrium conditions from its behaviour under the usual equilibrium situations.

  3. Internal dust recirculation system for a fluidized bed heat exchanger

    Science.gov (United States)

    Gamble, Robert L.; Garcia-Mallol, Juan A.

    1981-01-01

    A fluidized bed heat exchanger in which air is passed through a bed of particulate material containing fuel disposed in a housing. A steam/water natural circulation system is provided in a heat exchange relation to the bed and includes a steam drum disposed adjacent the bed and a tube bank extending between the steam drum and a water drum. The tube bank is located in the path of the effluent gases exiting from the bed and a baffle system is provided to separate the solid particulate matter from the effluent gases. The particulate matter is collected and injected back into the fluidized bed.

  4. Prediction of the heat transfer rate of a single layer wire-on-tube type heat exchanger using ANFIS

    Energy Technology Data Exchange (ETDEWEB)

    Hayati, Mohsen [Electrical Engineering Department, Faculty of Engineering, Razi University, Tagh-E-Bostan, Kermanshah 67149 (Iran); Computational Intelligence Research Center, Razi University, Tagh-E-Bostan, Kermanshah 67149 (Iran); Rezaei, Abbas; Seifi, Majid [Electrical Engineering Department, Faculty of Engineering, Razi University, Tagh-E-Bostan, Kermanshah 67149 (Iran)

    2009-12-15

    In this paper, we applied an Adaptive Neuro-Fuzzy Inference System (ANFIS) model for prediction of the heat transfer rate of the wire-on-tube type heat exchanger. Limited experimental data was used for training and testing ANFIS configuration with the help of hybrid learning algorithm consisting of backpropagation and least-squares estimation. The predicted values are found to be in good agreement with the actual values from the experiments with mean relative error less than 2.55%. Also, we compared the proposed ANFIS model to an ANN approach. Results show that the ANFIS model has more accuracy in comparison to ANN approach. Therefore, we can use ANFIS model to predict the performances of thermal systems in engineering applications, such as modeling heat exchangers for heat transfer analysis. (author)

  5. Performance investigation on a 4-bed adsorption desalination cycle with internal heat recovery scheme

    KAUST Repository

    Thu, Kyaw; Yanagi, Hideharu; Saha, Bidyut Baran; Ng, Kim Choon

    2016-01-01

    Multi-bed adsorption cycle with the internal heat recovery between the condenser and the evaporator is investigated for desalination application. A numerical model is developed for a 4-bed adsorption cycle implemented with the master

  6. Discovery of an 'internal heating effect' during electrochemical etching of polymeric dosimeters: a study of polymer characteristics

    International Nuclear Information System (INIS)

    Sohrabi, M.

    1986-01-01

    This paper investigates the importance of the internal heating effect by studying the role of different polymer physical and chemical characteristics (composition, effective foil size, thickness and electrical properties), on the rate of heating or temperature rise responses for cellulose tri-acetate (CTA), cellulose acetate (CA), allyl diglycol carbonate (CR-39), cellulose nitrate (CN), cellulose acetate butyrate (CAB), polyester (PES), polycarbonate (PC) and polyethylene (PE). Efforts have been made to justify the observed effects by different mechanisms such as dielectric loss, electro-osmosis, dielectrophoresis, and electrostriction. (author)

  7. The effect of heating rate on the surface chemistry of NiTi.

    Science.gov (United States)

    Undisz, Andreas; Hanke, Robert; Freiberg, Katharina E; Hoffmann, Volker; Rettenmayr, Markus

    2014-11-01

    The impact of the heating rate on the Ni content at the surface of the oxide layer of biomedical NiTi is explored. Heat treatment emulating common shape-setting procedures was performed by means of conventional and inductive heating for similar annealing time and temperature, applying various heating rates from ~0.25 K s(-1) to 250 K s(-1). A glow discharge optical emission spectroscopy method was established and employed to evaluate concentration profiles of Ni, Ti and O in the near-surface region at high resolution. The Ni content at the surface of the differently treated samples varies significantly, with maximum surface Ni concentrations of ~20 at.% at the lowest and ~1.5 at.% at the highest heating rate, i.e. the total amount of Ni contained in the surface region of the oxide layer decreases by >15 times. Consequently, the heating rate is a determinant for the biomedical characteristics of NiTi, especially since Ni available at the surface of the oxide layer may affect the hemocompatibility and be released promptly after surgical application of a respective implant. Furthermore, apparently contradictory results presented in the literature reporting surface Ni concentrations of ~3 at.% to >20 at.% after heat treatment are consistently explained considering the ascertained effect of the heating rate. Copyright © 2014 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

  8. Effect of phase change material on the heat transfer rate of different building materials

    Science.gov (United States)

    Hasan, Mushfiq; Alam, Shahnur; Ahmed, Dewan Hasan

    2017-12-01

    Phase change material (PCM) is widely known as latent heat storage. A comprehensive study is carried out to investigate the effect of PCM on heat transfer rate of building materials. Paraffin is used as PCM along with different conventional building materials to investigate the heat transfer rate from the heated region to the cold region. PCM is placed along with the three different types of building materials like plaster which is well know building material in urban areas and wood and straw which are commonly used in rural areas for roofing as well as wall panel material and investigated the heat transfer rate. An experimental setup was constructed with number of rectangular shape aluminum detachable casing (as cavity) and placed side by side. Series of rectangular cavity filled with convent ional building materials and PCM and these were placed in between two chambers filled with water at different temperature. Building materials and PCM were placed in different cavities with different combinations and investigated the heat transfer rate. The results show that using the PCM along with other building materials can be used to maintain lower temperature at the inner wall and chamber of the cold region. Moreover, the placement or orientation of the building materials and PCM make significant contribution to heat transfer rate from the heated zone to the cold zone.

  9. Abstracts of international symposium on heat and mass transfer under plasma conditions

    International Nuclear Information System (INIS)

    1994-01-01

    The international symposium on heat and mass transfer under plasma conditions was held on 4-8 July 1994 in Cesme, Izmir, Turkey. The spesialists discussed heat and mass transfer in the field of plasma processing at the meeting. More than 70 papers were presented in the meeting

  10. Abstracts of international symposium on heat and mass transfer under plasma conditions

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1994-12-31

    The international symposium on heat and mass transfer under plasma conditions was held on 4-8 July 1994 in Cesme, Izmir, Turkey. The spesialists discussed heat and mass transfer in the field of plasma processing at the meeting. More than 70 papers were presented in the meeting.

  11. Effect of the Heat Flux Density on the Evaporation Rate of a Distilled Water Drop

    Directory of Open Access Journals (Sweden)

    Ponomarev Konstantin

    2016-01-01

    Full Text Available This paper presents the experimental dependence of the evaporation rate of a nondeaerated distilled water drop from the heat flux density on the surfaces of non-ferrous metals (copper and brass. A drop was placed on a heated substrate by electronic dosing device. To obtain drop profile we use a shadow optical system; drop symmetry was controlled by a high-speed video camera. It was found that the evaporation rate of a drop on a copper substrate is greater than on a brass. The evaporation rate increases intensively with raising volume of a drop. Calculated values of the heat flux density and the corresponding evaporation rates are presented in this work. The evaporation rate is found to increase intensively on the brass substrate with raising the heat flux density.

  12. Inverse problem of estimating transient heat transfer rate on external wall of forced convection pipe

    International Nuclear Information System (INIS)

    Chen, W.-L.; Yang, Y.-C.; Chang, W.-J.; Lee, H.-L.

    2008-01-01

    In this study, a conjugate gradient method based inverse algorithm is applied to estimate the unknown space and time dependent heat transfer rate on the external wall of a pipe system using temperature measurements. It is assumed that no prior information is available on the functional form of the unknown heat transfer rate; hence, the procedure is classified as function estimation in the inverse calculation. The accuracy of the inverse analysis is examined by using simulated exact and inexact temperature measurements. Results show that an excellent estimation of the space and time dependent heat transfer rate can be obtained for the test case considered in this study

  13. Measurements of the evaporation rate upon evaporation of thin layer at different heating modes

    OpenAIRE

    Gatapova E.Ya.; Korbanova E.G.

    2017-01-01

    Technique for measurements of the evaporation rate of a heated liquid layer is presented. The local minimum is observed which is associated with the point of equilibrium of the liquid–gas interface. It is shown when no heat is applied to the heating element temperature in gas phase is larger than in liquid, and evaporation occurs with the rate of 0.014–0.018 μl/s. Then evaporation rate is decreasing with increasing the heater temperature until the equilibrium point is reached at the liquid–ga...

  14. Characterizing high-temperature deformation of internally heated nuclear fuel element simulators

    Energy Technology Data Exchange (ETDEWEB)

    Belov, A.I.; Fong, R.W.L.; Leitch, B.W.; Nitheanandan, T.; Williams, A., E-mail: alexander.belov@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada)

    2016-06-15

    The sag behaviour of a simulated nuclear fuel element during high-temperature transients has been investigated in an experiment utilizing an internal indirect heating method. The major motivation of the experiment was to improve understanding of the dominant mechanisms underlying the element thermo-mechanical response under loss-of-coolant accident conditions and to obtain accurate experimental data to support development of 3-D computational fuel element models. The experiment was conducted using an electrically heated CANDU fuel element simulator. Three consecutive thermal cycles with peak temperatures up to ≈1000 {sup o}C were applied to the element. The element sag deflections and sheath temperatures were measured. On heating up to 600 {sup o}C, only minor lateral deflections of the element were observed. Further heating to above 700 {sup o}C resulted in an element multi-rate creep and significant permanent bow. Post-test visual and X-ray examinations revealed a pronounced necking of the sheath at the pellet-to-pellet interface locations. A wall thickness reduction was detected in the necked region that is interpreted as a sheath longitudinal strain localization effect. The sheath cross-sectioning showed signs of a 'hard' pellet-cladding interaction due to the applied cycles. A 3-D model of the experiment was generated using the ANSYS finite element code. As a fully coupled thermal mechanical simulation is computationally expensive, it was deemed sufficient to use the measured sheath temperatures as a boundary condition, and thus an uncoupled mechanical simulation only was conducted. The ANSYS simulation results match the experiment sag observations well up to the point at which the fuel element started cooling down. (author)

  15. Core-debris quenching-heat-transfer rates under top- and bottom-reflood conditions

    International Nuclear Information System (INIS)

    Ginsberg, T.; Tutu, N.; Klages, J.; Schwarz, C.E.; Sanborn, Y.

    1983-02-01

    This paper presents recent experimental data for the quench-heat-transfer characteristics of superheated packed beds of spheres which were cooled, in separate experiments, by top- and bottom-flooding modes. Experiments were carried out with beds of 3-mm steel spheres of 330-mm height. The initial bed temperature was 810 K. The observed heat-transfer rates are strongly dependent on the mode of water injection. The results suggest that top-flood bed quench heat transfer is limited by the rate at which water can penetrate the bed under two-phase countercurrent-flow conditions. With bottom-reflood the heat-transfer rate is an order-of-magnitude greater than under top-flood conditions and appears to be limited by particle-to-fluid film boiling heat transfer

  16. Can reptile embryos influence their own rates of heating and cooling?

    Directory of Open Access Journals (Sweden)

    Wei-Guo Du

    Full Text Available Previous investigations have assumed that embryos lack the capacity of physiological thermoregulation until they are large enough for their own metabolic heat production to influence nest temperatures. Contrary to intuition, reptile embryos may be capable of physiological thermoregulation. In our experiments, egg-sized objects (dead or infertile eggs, water-filled balloons, glass jars cooled down more rapidly than they heated up, whereas live snake eggs heated more rapidly than they cooled. In a nest with diel thermal fluctuations, that hysteresis could increase the embryo's effective incubation temperature. The mechanisms for controlling rates of thermal exchange are unclear, but may involve facultative adjustment of blood flow. Heart rates of snake embryos were higher during cooling than during heating, the opposite pattern to that seen in adult reptiles. Our data challenge the view of reptile eggs as thermally passive, and suggest that embryos of reptile species with large eggs can influence their own rates of heating and cooling.

  17. Urban and rural mortality rates during heat waves in Berlin and Brandenburg, Germany

    International Nuclear Information System (INIS)

    Gabriel, Katharina M.A.; Endlicher, Wilfried R.

    2011-01-01

    In large cities such as Berlin, human mortality rates increase during intense heat waves. Analysis of relevant data from north-eastern Germany revealed that, during the heat waves that occurred between 1990 and 2006, health risks were higher for older people in both rural and urban areas, but that, during the two main heat waves within that 17-year period of time, the highest mortality rates were from the city of Berlin, and in particular from its most densely built-up districts. Adaptation measures will need to be developed, particularly within urban areas, in order to cope with the expected future intensification of heat waves due to global climate change. - Highlights: → Periods of heat stress enhance mortality rates in Berlin and Brandenburg. → Heat-related mortality is an urban as well as a rural problem. → During extreme events highest mortality rates can be found in the city centre. → Mortality rates correlate well with the distribution of sealed surfaces. → Health risks are higher for older than for younger people. - During periods of severe heat stress the pattern of mortality rates in Berlin and Brandenburg was found to correlate well with the distribution of sealed surfaces.

  18. Method and apparatus for active control of combustion rate through modulation of heat transfer from the combustion chamber wall

    Science.gov (United States)

    Roberts, Jr., Charles E.; Chadwell, Christopher J.

    2004-09-21

    The flame propagation rate resulting from a combustion event in the combustion chamber of an internal combustion engine is controlled by modulation of the heat transfer from the combustion flame to the combustion chamber walls. In one embodiment, heat transfer from the combustion flame to the combustion chamber walls is mechanically modulated by a movable member that is inserted into, or withdrawn from, the combustion chamber thereby changing the shape of the combustion chamber and the combustion chamber wall surface area. In another embodiment, heat transfer from the combustion flame to the combustion chamber walls is modulated by cooling the surface of a portion of the combustion chamber wall that is in close proximity to the area of the combustion chamber where flame speed control is desired.

  19. Estimation of shutdown heat generation rates in GHARR-1 due to ...

    African Journals Online (AJOL)

    Fission products decay power and residual fission power generated after shutdown of Ghana Research Reactor-1 (GHARR-1) by reactivity insertion accident were estimated by solution of the decay and residual heat equations. A Matlab program code was developed to simulate the heat generation rates by fission product ...

  20. Rapid self-heating and internal temperature sensing of lithium-ion batteries at low temperatures

    International Nuclear Information System (INIS)

    Zhang, Guangsheng; Ge, Shanhai; Xu, Terrence; Yang, Xiao-Guang; Tian, Hua; Wang, Chao-Yang

    2016-01-01

    Highlights: • Self-heating lithium-ion battery (SHLB) structure provided a practical solution to the poor performance at subzero temperatures. • We report an improved SHLB that heats from −20 °C to 0 °C in 12.5 seconds, or 56% more rapidly, while consuming 24% less energy than previously reported. • The nickel foil heating element embedded inside a SHLB cell plays a dominant role in rapid self-heating. • The embedded nickel foil can simultaneously perform as an internal temperature sensor (ITS). • 2-sheet design self-heats faster than 1-sheet design due to more uniform internal temperature distribution. - Abstract: The recently discovered self-heating lithium-ion battery structure provided a practical solution to the poor performance at subzero temperatures that has hampered battery technology for decades. Here we report an improved self-heating lithium-ion battery (SHLB) that heats from −20 °C to 0 °C in 12.5 seconds, or 56% more rapidly, while consuming 24% less energy than that reported previously. We reveal that a nickel foil heating element embedded inside a SHLB cell plays a dominant role in self-heating and we experimentally demonstrate that a 2-sheet design can achieve dramatically accelerated self-heating due to more uniform internal temperature distribution. We also report, for the first time, that this embedded nickel foil can simultaneously perform as an internal temperature sensor (ITS) due to the perfectly linear relationship between the foil’s electrical resistance and temperature.

  1. The international heat pump market as seen from the 'Business Development' point of view

    International Nuclear Information System (INIS)

    Schilli, A. S.; Afjei, T.

    2002-01-01

    This article takes a close look at the prerequisites that are decisive for successful business development in the international heat pump market and the challenges placed by them. The article examines the quality of market information and data that is available, especially regarding the market potential for heating and cooling in residential, commercial and industrial buildings. The results of various national and international surveys and studies made in this area are discussed. Several characteristics of the heat pump market - both in the buying and selling areas - are examined in order to clarify the requirements for market and business development in these sectors

  2. Measuring the linear heat generation rate of a nuclear reactor fuel pin

    International Nuclear Information System (INIS)

    Smith, R.D.

    1981-01-01

    A miniature gamma thermometer is described which is capable of travelling through bores distributed in an array through a nuclear reactor core and measure the linear heat generation rate of the fuel pins. (U.K.)

  3. Effect of surface roughness on the heating rates of large-angled hypersonic blunt cones

    Science.gov (United States)

    Irimpan, Kiran Joy; Menezes, Viren

    2018-03-01

    Surface-roughness caused by the residue of an ablative Thermal Protection System (TPS) can alter the turbulence level and surface heating rates on a hypersonic re-entry capsule. Large-scale surface-roughness that could represent an ablated TPS, was introduced over the forebody of a 120° apex angle blunt cone, in order to test for its influence on surface heating rates in a hypersonic freestream of Mach 8.8. The surface heat transfer rates measured on smooth and roughened models under the same freestream conditions were compared. The hypersonic flow-fields of the smooth and rough-surfaced models were visualized to analyse the flow physics. Qualitative numerical simulations and pressure measurements were carried out to have an insight into the high-speed flow physics. Experimental observations under moderate Reynolds numbers indicated a delayed transition and an overall reduction of 17-46% in surface heating rates on the roughened model.

  4. Average Rate of Heat-Related Hospitalizations in 23 States, 2001-2010

    Data.gov (United States)

    U.S. Environmental Protection Agency — This map shows the 2001–2010 average rate of hospitalizations classified as “heat-related” by medical professionals in 23 states that participate in CDC’s...

  5. Nonlinear thermal convection in a layer of nanofluid under G-jitter and internal heating effects

    Directory of Open Access Journals (Sweden)

    Bhadauria B. S.

    2014-01-01

    Full Text Available This paper deals with a mathematical model of controlling heat transfer in nanofluids. The time-periodic vertical vibrations of the system are considered to effect an external control of heat transport along with internal heating effects. A weakly non-linear stability analysis is based on the five-mode Lorenz model using which the Nusselt number is obtained as a function of the thermal Rayleigh number, nano-particle concentration based Rayleigh number, Prandtl number, Lewis number, modified diffusivity ratio, amplitude and frequency of modulation. It is shown that modulation can be effectively used to control convection and thereby heat transport. Further, it is found that the effect of internal Rayleigh number is to enhance the heat and nano-particles transport.

  6. Dry out of a fluidized particle bed with internal heat generation

    International Nuclear Information System (INIS)

    Keowen, R.S.; Catton, I.

    1975-03-01

    An apparatus was designed to adequately simulate the characteristics of a particle bed formed by nuclear reactor fuel after the reactor has been operable for some length of time at high power. This was accomplished by using a 10 KW, 453 Kc induction heater, coupled through a multi-turn work coil to particle beds of cast steel shot and lead shot in water. The temperature response and dryout condition was determined for various bed levels, particle diameters, and heat fluxes. Analysis of the data retrieved from the bed was used to generate a family of curves to predict the necessary conditions for dryout to occur within a fluidized particle bed with internal heat generation. The results presented here, with internal heat generation, show that previous results with bottom heating and volume heating are conservative. (U.S.)

  7. Conception rate of artificially inseminated Holstein cows affected by cloudy vaginal mucus, under intense heat conditions

    OpenAIRE

    Miguel Mellado; Laura Maricela Lara; Francisco Gerardo Veliz; María Ángeles de Santiago; Leonel Avendaño-Reyes; Cesar Meza-Herrera; José Eduardo Garcia

    2015-01-01

    The objective of this work was to obtain prevalence estimates of cloudy vaginal mucus in artificially inseminated Holstein cows raised under intense heat, in order to assess the effect of meteorological conditions on its occurrence during estrus and to determine its effect on conception rate. In a first study, an association was established between the occurrence of cloudy vaginal mucus during estrus and the conception rate of inseminated cows (18,620 services), raised under intense heat (mea...

  8. NASA Physical Sciences - Presentation to Annual Two Phase Heat Transfer International Topical Team Meeting

    Science.gov (United States)

    Chiaramonte, Francis; Motil, Brian; McQuillen, John

    2014-01-01

    The Two-phase Heat Transfer International Topical Team consists of researchers and members from various space agencies including ESA, JAXA, CSA, and RSA. This presentation included descriptions various fluid experiments either being conducted by or planned by NASA for the International Space Station in the areas of two-phase flow, flow boiling, capillary flow, and crygenic fluid storage.

  9. Heat transfer and thermodynamic performance of convective–radiative cooling double layer walls with temperature-dependent thermal conductivity and internal heat generation

    International Nuclear Information System (INIS)

    Torabi, Mohsen; Zhang, Kaili

    2015-01-01

    Highlights: • First and second laws of thermodynamics have been investigated in a composite wall. • Convective–radiative heat transfer is assumed on both surfaces. • Optimum interface location is calculated to minimize the total entropy generation rate. • Thermal conductivities ratio has great effects on the temperature and entropy generation. - Abstract: Composite geometries have numerous applications in industry and scientific researches. This work investigates the temperature distribution, and local and total entropy generation rates within two-layer composite walls using conjugate convection and radiation boundary conditions. Thermal conductivities of the materials of walls are assumed temperature-dependent. Temperature-dependent internal heat generations are also incorporated into the modeling. The differential transformation method (DTM) is used as an analytical technique to tackle the highly nonlinear system of ordinary differential equations. Thereafter, the local and total entropy generation rates are calculated using the DTM formulated temperature distribution. An exact analytical solution, for the temperature-independent model without radiation effect, is also derived. The correctness and accuracy of the DTM solution are checked against the exact solution. After verification, effects of thermophysical parameters such as location of the interface, convection–conduction parameters, radiation–conduction parameters, and internal heat generations, on the temperature distribution, and both local and total entropy generation rates are examined. To deliver the minimum total entropy generation rate, optimum values for some parameters are also found. Since composite walls are widely used in many fields, the abovementioned investigation is a beneficial tool for many engineering industries and scientific fields to minimize the entropy generation, which is the exergy destruction, of the system

  10. Heat accumulation during high repetition rate ultrafast laser interaction: Waveguide writing in borosilicate glass

    International Nuclear Information System (INIS)

    Zhang, Haibin; Eaton, Shane M; Li, Jianzhao; Herman, Peter R

    2007-01-01

    During high repetition rate (>200 kHz) ultrafast laser waveguide writing, visible heat modified zones surrounding the formed waveguide occur as a result of heat accumulation. The radii of the heat-modified zones increase with the laser net fluence, and were found to correlate with the formation of low-loss and cylindrically symmetric optical waveguides. A numerical thermal model based on the finite difference method is applied here to account for cumulative heating and diffusion effects. The model successfully shows that heat propagation and accumulation accurately predict the radius of the 'heat modified' zones observed in borosilicate glass waveguides formed across a wide range of laser exposure conditions. Such modelling promises better control of thermal effects for optimizing the fabrication and performance of three-dimensional optical devices in transparent materials

  11. Effect of Heating Rate on Grain Structure and Superplasticity of 7B04 Aluminum Alloy Sheets

    Directory of Open Access Journals (Sweden)

    CHEN Min

    2017-03-01

    Full Text Available Fine-grained 7B04 aluminum alloy sheets were manufactured through thermo-mechanical treatment. The effects of anneal heating rate on grain structure and superplasticity were investigated using electron back scattering diffraction(EBSD and high temperature tensile test. The results show that at the heating rate of 5.0×10-3K/s, the average grain sizes along the rolling direction(RD and normal direction(ND are 28.2μm and 13.9μm respectively, the nucleation rate is 1/1000. With the increase of heating rate, the average grain size decreases, and the nucleation rate increases. When the heating rate increases to 30.0K/s, the average grain sizes along the RD and ND decrease respectively to 9.9μm and 5.1μm, and the nucleation rate increases to 1/80. Besides, with the increase of heating rate, the elongation of sheets also increases. The elongation of the specimens increases from 100% to 730% under the deforming condition of 773K/8×10-4s-1.

  12. Equipment for heating the exhaust gases of internal combustion engines in order to improve afterburning

    Energy Technology Data Exchange (ETDEWEB)

    Masaki,

    1976-04-15

    The device described here serves to heat exhaust gases of internal combustion engines by heat exchange with hot gases and also, in cold engines, to raise the temperature of the fuel-air mixture drawn in by the engine. The device is installed next to the outlet opening of the engine. It consists of a burner to generate the hot gas, as well as a heat exchanger permitting heat supply to the exhaust gases and a hot-gas line leading to the intake line. Heating of the air is taken in leads to a better atomization of the mixture and thus to improved combustion. Heating of the exhaust gases improves afterburning. The burner generating the hot gas is shut off when the normal operational temperature of the engine is reached. The temperature is controlled by means of a temperature sensor installed in the device.

  13. Thermal Death Kinetics of Conogethes Punctiferalis (Lepidoptera: Pyralidae) as Influenced by Heating Rate and Life Stage.

    Science.gov (United States)

    Hou, Lixia; Du, Yanli; Johnson, Judy A; Wang, Shaojin

    2015-10-01

    Thermal death kinetics of Conogethes punctiferalis (Guenée) (Lepidoptera: Pyralidae) at different life stages, heating rate, and temperature is essential for developing postharvest treatments to control pests in chestnuts. Using a heating block system (HBS), the most heat-tolerant life stage of C. punctiferalis and the effects of heating rate (0.1, 0.5, 1, 5, and 10°C/min) on insect mortality were determined. The thermal death kinetic data of fifth-instar C. punctiferalis were obtained at temperatures between 44 and 50°C at a heating rate of 5°C/min. The results showed that the relative heat tolerance of C. punctiferalis was found to be fifth instars>pupae> third instars> eggs. To avoid the enhanced thermal tolerance of C. punctiferalis at low heating rates (0.1 or 0.5°C/min), a high heating rate of 5°C/min was selected to simulate the fast radio frequency heating in chestnuts and further determine the thermal death kinetic data. Thermal death curves of C. punctiferalis followed a 0th-order kinetic reaction model. The minimum exposure time to achieve 100% mortality was 55, 12, 6, and 3 min at 44, 46, 48, and 50°C, respectively. The activation energy for controlling C. punctiferalis was 482.15 kJ/mol with the z value of 4.09°C obtained from the thermal death-time curve. The information provided by thermal death kinetics for C. punctiferalis is useful in developing effective postharvest thermal treatment protocols for disinfesting chestnuts. © The Authors 2015. Published by Oxford University Press on behalf of Entomological Society of America. All rights reserved. For Permissions, please email: journals.permissions@oup.com.

  14. Improvement in Performance of a Thermochemical Heat Storage System by Implementing an Internal Heat Recovery System

    NARCIS (Netherlands)

    Gaeini, M.; Saris, L.; Zondag, H.A.; Rindt, C.C.M.

    A lab-scale prototype of a thermochemical heat storage system, employing a water-zeolite 13X as the working pair, is designed and optimized for providing hot tap water. During the hydration process, humid air is introduced to the packed bed reactor filled with dehydrated zeolite 13X, and the

  15. Numerical simulation of magnetohydrodynamic (MHD) flow with internal heat generation

    International Nuclear Information System (INIS)

    Bokade, Vipin; Bhandarkar, U.V.; Bodi, Kowsik

    2016-01-01

    A strong magnetic field is used to confine the plasma in a fusion reactor. This magnetic field also affects the flow of Lead-Lithium (breeder/coolant) in the breeding blanket. So it is important to study MHD flow of Lead-Lithium (Pb-Li). Open-source toolbox, OpenFOAM, is used to study single phase behaviour of Pb-Li. As the induced magnetic field is very small, Ni et al. electric potential algorithm is employed in OpenFOAM and validated with analytical results. This solver can also solve the temperature field with heat source term. Simulations are carried out in 2D straight channel for various values of Hartmann Number ranging from 100 to 5000 and velocity profile, temperature, current density and pressure drop are studied. (author)

  16. The heating rate in the tropical tropopause region; Die Erwaermungsrate in der tropischen Tropopausenregion

    Energy Technology Data Exchange (ETDEWEB)

    Hamann, Ulrich

    2010-07-01

    The major part of the movement of air masses from the troposphere to the stratosphere takes place in the tropics. The conveyed air mass is transported with the Brewer-Dobson circulation poleward and therefore influences the global stratospheric composition. An important cause variable for the transport of air through the tropical tropopause layer (TTL) is the radiative heating, which is investigated in this work. The influence of trace gases, temperature, and cloudiness on the heating rate is quantified, especially the effect of the overlap of several cloud layers is discussed. The heating rate in the tropics is simulated for one year. Regional differences of the heating rate profile appear between convective and stably stratified regions. By means of trace gas concentrations, temperature, and heating rates it is determined that an enhanced transport of air through the TTL took place between January and April 2007. The comparison with previous works shows that accurate input data sets of trace gases, temperature, and cloudiness and exact methods for the simulation of the radiative transfer are indispensable for modeling of the heating rate with the required accuracy. (orig.)

  17. Analysis of heating effect on the process of high deposition rate microcrystalline silicon

    International Nuclear Information System (INIS)

    Xiao-Dan, Zhang; He, Zhang; Chang-Chun, Wei; Jian, Sun; Guo-Fu, Hou; Shao-Zhen, Xiong; Xin-Hua, Geng; Ying, Zhao

    2010-01-01

    A possible heating effect on the process of high deposition rate microcrystalline silicon has been studied. It includes the discharge time-accumulating heating effect, discharge power, inter-electrode distance, and total gas flow rate induced heating effect. It is found that the heating effects mentioned above are in some ways quite similar to and in other ways very different from each other. However, all of them will directly or indirectly cause the increase of the substrate surface temperature during the process of depositing microcrystalline silicon thin films, which will affect the properties of the materials with increasing time. This phenomenon is very serious for the high deposition rate of microcrystalline silicon thin films because of the high input power and the relatively small inter-electrode distance needed. Through analysis of the heating effects occurring in the process of depositing microcrystalline silicon, it is proposed that the discharge power and the heating temperature should be as low as possible, and the total gas flow rate and the inter-electrode distance should be suitable so that device-grade high quality deposition rate microcrystalline silicon thin films can be fabricated

  18. Effect of Heating Rate on Pyrolysis Behavior and Kinetic Characteristics of Siderite

    Directory of Open Access Journals (Sweden)

    Xiaolong Zhang

    2017-11-01

    Full Text Available The pyrolysis characteristics of siderite at different heating rates under the neutral atmosphere were investigated using various tools, including comprehensive thermal analyzer, tube furnace, X-ray diffraction (XRD, scanning electron microscope (SEM, energy-dispersive spectrometry (EDS and vibrating specimen magnetometer (VSM measurements. The reaction of siderite pyrolysis followed the one-step reaction under the neutral atmosphere: FeCO3 → Fe3O4 + CO2 + CO. As the increasing of heating rate, the start and end pyrolysis temperatures and temperate where maximum weight loss rate occurred increased, while the total mass loss were essentially the same. Increasing heating rate within a certain range was in favor of shortening the time of each reaction stage, and the maximum conversion rate could be reached with a short time. The most probable mechanism function for non-isothermal pyrolysis of siderite at different heating rates was A1/2 reaction model (nucleation and growth reaction. With increasing heating rate, the corresponding activation energies and the pre-exponential factors increased, from 446.13 to 505.19 kJ∙mol−1, and from 6.67 × 10−18 to 2.40 × 10−21, respectively. All siderite was transformed into magnetite with a porous structure after pyrolysis, and some micro-cracks were formed into the particles. The magnetization intensity and specific susceptibility increased significantly, which created favorable conditions for the further effective concentration of iron ore.

  19. Thermoluminescence study of X-ray irradiated muscovite mineral under various heating rate

    International Nuclear Information System (INIS)

    Kalita, J.M.; Wary, G.

    2014-01-01

    The thermoluminescence (TL) glow curves of X-ray irradiated micro-grain natural muscovite were recorded within 298–520 K at various linear heating rates (2 K/s, 4 K/s, 6 K/s, 8 K/s and 10 K/s). Natural TL of muscovite was checked, but no significant TL was observed within 298–520 K in any heating rate. Within the heating rate 2–10 K/s only a low temperature distinct peak was observed in the temperature range 348–357 K. The TL parameters such as activation energy, order of kinetic, geometrical symmetry factor and pre-exponential frequency factor were investigated from the glow peak by Peak Shape (PS) method and Computerized Glow Curve Deconvolution (CGCD) technique. At lowest heating rate the glow peak obeys non-first order kinetic and at the highest heating rate it follows the second order kinetic. The variation of peak integrals, peak maximum temperatures, FWHM and activation energy with heating rates were investigated, and the glow curves at higher rates were found to be influenced by the presence of the thermal quenching. The thermal quenching activation energy and pre-exponential factor were calculated and found to be 2.31±0.02 eV and 3.46×10 14 s −1 , respectively. -- Highlights: • Muscovite is a silicate mineral with chemical formula KAl 2 (Si 3 Al)O 10 (OH,F) 2 . • TL of natural and X-ray induced muscovite was studied under various heating rates. • TL parameters were evaluated by Peak Shape and CGCD method. • Thermal quenching parameters (W and C) of muscovite were evaluated

  20. Performance of cable-in-conduit conductors in ITER [International Thermonuclear Experimental Reactor] toroidal field coils with varying heat loads

    International Nuclear Information System (INIS)

    Kerns, J.A.; Wong, R.L.

    1989-01-01

    The toroidal field (TF) coils in the International Thermonuclear Experimental Reactor (ITER) will operate with varying heat loads generated by ac losses and nuclear heating. The total heat load is estimated to be 2 kW per TF coil under normal operation and can be higher for different operating scenarios. Ac losses are caused by ramping the poloidal field (PF) for plasma initiation, burn, and shutdown; nuclear heating results from neutrons that penetrate into the coil past the shield. Present methods to reduce or eliminate these losses lead to larger and more expensive machines, which are unacceptable with today's budget constraints. A suitable solution is to design superconductors that operate with high heat loads. The cable-in-conduit conductor (CICC) can operate with high heat loads. One CICC design is analyzed for its thermal performance using two computer codes developed at LLNL. One code calculates the steady state flow conditions along the flow path, while the other calculates the transient conditions in the flow. We have used these codes to analyze the superconductor performance during the burn phase of the ITER plasma. The results of these analyses give insight to the choice of flow rate on superconductor performance. 4 refs., 5 figs

  1. Does attenuated skin blood flow lower sweat rate and the critical environmental limit for heat balance during severe heat exposure?

    Science.gov (United States)

    Cramer, Matthew N; Gagnon, Daniel; Crandall, Craig G; Jay, Ollie

    2017-02-01

    What is the central question of this study? Does attenuated skin blood flow diminish sweating and reduce the critical environmental limit for heat balance, which indicates maximal heat loss potential, during severe heat stress? What is the main finding and its importance? Isosmotic hypovolaemia attenuated skin blood flow by ∼20% but did not result in different sweating rates, mean skin temperatures or critical environmental limits for heat balance compared with control and volume-infusion treatments, suggesting that the lower levels of skin blood flow commonly observed in aged and diseased populations may not diminish maximal whole-body heat dissipation. Attenuated skin blood flow (SkBF) is often assumed to impair core temperature (T c ) regulation. Profound pharmacologically induced reductions in SkBF (∼85%) lead to impaired sweating, but whether the smaller attenuations in SkBF (∼20%) more often associated with ageing and certain diseases lead to decrements in sweating and maximal heat loss potential is unknown. Seven healthy men (28 ± 4 years old) completed a 30 min equilibration period at 41°C and a vapour pressure (P a ) of 2.57 kPa followed by incremental steps in P a of 0.17 kPa every 6 min to 5.95 kPa. Differences in heat loss potential were assessed by identifying the critical vapour pressure (P crit ) at which an upward inflection in T c occurred. The following three separate treatments elicited changes in plasma volume to achieve three distinct levels of SkBF: control (CON); diuretic-induced isosmotic dehydration to lower SkBF (DEH); and continuous saline infusion to maintain SkBF (SAL). The T c , mean skin temperature (T sk ), heart rate, mean laser-Doppler flux (forearm and thigh; LDF mean ), mean local sweat rate (forearm and thigh; LSR mean ) and metabolic rate were measured. In DEH, a 14.2 ± 5.7% lower plasma volume resulted in a ∼20% lower LDF mean in perfusion units (PU) (DEH, 139 ± 23 PU; CON, 176 ± 22 PU; and SAL

  2. Isothermal calorimeter for measurements of time-dependent heat generation rate in individual supercapacitor electrodes

    Science.gov (United States)

    Munteshari, Obaidallah; Lau, Jonathan; Krishnan, Atindra; Dunn, Bruce; Pilon, Laurent

    2018-01-01

    Heat generation in electric double layer capacitors (EDLCs) may lead to temperature rise and reduce their lifetime and performance. This study aims to measure the time-dependent heat generation rate in individual carbon electrode of EDLCs under various charging conditions. First, the design, fabrication, and validation of an isothermal calorimeter are presented. The calorimeter consisted of two thermoelectric heat flux sensors connected to a data acquisition system, two identical and cold plates fed with a circulating coolant, and an electrochemical test section connected to a potentiostat/galvanostat system. The EDLC cells consisted of two identical activated carbon electrodes and a separator immersed in an electrolyte. Measurements were performed on three cells with different electrolytes under galvanostatic cycling for different current density and polarity. The measured time-averaged irreversible heat generation rate was in excellent agreement with predictions for Joule heating. The reversible heat generation rate in the positive electrode was exothermic during charging and endothermic during discharging. By contrast, the negative electrode featured both exothermic and endothermic heat generation during both charging and discharging. The results of this study can be used to validate existing thermal models, to develop thermal management strategies, and to gain insight into physicochemical phenomena taking place during operation.

  3. A combined thermodynamic cycle used for waste heat recovery of internal combustion engine

    International Nuclear Information System (INIS)

    He, Maogang; Zhang, Xinxin; Zeng, Ke; Gao, Ke

    2011-01-01

    In this paper, we present a steady-state experiment, energy balance and exergy analysis of exhaust gas in order to improve the recovery of the waste heat of an internal combustion engine (ICE). Considering the different characteristics of the waste heat of exhaust gas, cooling water, and lubricant, a combined thermodynamic cycle for waste heat recovery of ICE is proposed. This combined thermodynamic cycle consists of two cycles: the organic Rankine cycle (ORC), for recovering the waste heat of lubricant and high-temperature exhaust gas, and the Kalina cycle, for recovering the waste heat of low-temperature cooling water. Based on Peng–Robinson (PR) equation of state (EOS), the thermodynamic parameters in the high-temperature ORC were calculated and determined via an in-house computer program. Suitable working fluids used in high-temperature ORC are proposed and the performance of this combined thermodynamic cycle is analyzed. Compared with the traditional cycle configuration, more waste heat can be recovered by the combined cycle introduced in this paper. -- Highlights: ► We study the energy balance of fuel in internal combustion engine. ► Heat recovery effect of exhaust gas is good when ICE is at a high-load condition. ► We propose a new combined thermodynamic cycle for waste heat of ICE. ► The combined cycle has a higher recovery efficiency than previous configurations.

  4. Internal (Annular) and Compressible External (Flat Plate) Turbulent Flow Heat Transfer Correlations.

    Energy Technology Data Exchange (ETDEWEB)

    Dechant, Lawrence [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States); Smith, Justin [Sandia National Lab. (SNL-NM), Albuquerque, NM (United States)

    2016-01-01

    Here we provide a discussion regarding the applicability of a family of traditional heat transfer correlation based models for several (unit level) heat transfer problems associated with flight heat transfer estimates and internal flow heat transfer associated with an experimental simulation design (Dobranich 2014). Variability between semi-empirical free-flight models suggests relative differences for heat transfer coefficients on the order of 10%, while the internal annular flow behavior is larger with differences on the order of 20%. We emphasize that these expressions are strictly valid only for the geometries they have been derived for e.g. the fully developed annular flow or simple external flow problems. Though, the application of flat plate skin friction estimate to cylindrical bodies is a traditional procedure to estimate skin friction and heat transfer, an over-prediction bias is often observed using these approximations for missile type bodies. As a correction for this over-estimate trend, we discuss a simple scaling reduction factor for flat plate turbulent skin friction and heat transfer solutions (correlations) applied to blunt bodies of revolution at zero angle of attack. The method estimates the ratio between axisymmetric and 2-d stagnation point heat transfer skin friction and Stanton number solution expressions for sub-turbulent Reynolds numbers %3C1x10 4 . This factor is assumed to also directly influence the flat plate results applied to the cylindrical portion of the flow and the flat plate correlations are modified by

  5. PREFACE: International Workshop on Multi-Rate Processes and Hysteresis

    Science.gov (United States)

    Mortell, Michael P.; O'Malley, Robert E.; Pokrovskii, Alexei; Rachinskii, Dmitrii; Sobolev, Vladimir A.

    2008-07-01

    We are interested in singular perturbation problems and hysteresis as common strongly nonlinear phenomena that occur in many industrial, physical and economic systems. The wording `strongly nonlinear' means that linearization will not encapsulate the observed phenomena. Often these two types of phenomena are manifested for different stages of the same or similar processes. A number of fundamental hysteresis models can be considered as limit cases of time relaxation processes, or admit an approximation by a differential equation which is singular with respect to a particular parameter. However, the amount of interaction between practitioners of theories of systems with time relaxation and systems with hysteresis (and between the `relaxation' and `hysteresis' research communities) is still low, and cross-fertilization is small. In recent years Ireland has become a home for a series of prestigious International Workshops in Singular Perturbations and Hysteresis: International Workshop on Multi-rate Processes and Hysteresis (University College Cork, Ireland, 3-8 April 2006). Proceedings are published in Journal of Physics: Conference Series, volume 55. See further information at http://euclid.ucc.ie/murphys2008.htm International Workshop on Hysteresis and Multi-scale Asymptotics (University College Cork, Ireland, 17-21 March 2004). Proceedings are published in Journal of Physics: Conference Series, volume 22. See further information at http://euclid.ucc.ie/murphys2006.htm International Workshop on Relaxation Oscillations and Hysteresis (University College Cork, Ireland, 1-6 April 2002). The related collection of invited lectures, was published as a volume Singular Perturbations and Hysteresis, SIAM, Philadelphia, 2005. See further information at http://euclid.ucc.ie/hamsa2004.htm International Workshop on Geometrical Methods of Nonlinear Analysis and Semiconductor Laser Dynamics (University College Cork, Ireland, 5-5 April 2001). A collection of invited papers has been

  6. The Effect of Heat Treatments and Coatings on the Outgassing Rate of Stainless Steel Chambers

    Energy Technology Data Exchange (ETDEWEB)

    Mamum, Md Abdullah A. [Old Dominion Univ., Norfolk, VA (United States); Elmustafa, Abdelmageed A, [Old Dominion Univ., Norfolk, VA (United States); Stutzman, Marcy L. [JLAB, Newport News, VA (United States); Adderley, Philip A. [JLAB, Newport News, VA (United States); Poelker, Matthew [JLAB, Newport News, VA (United States)

    2014-03-01

    The outgassing rates of four nominally identical 304L stainless steel vacuum chambers were measured to determine the effect of chamber coatings and heat treatments. One chamber was coated with titanium nitride (TiN) and one with amorphous silicon (a-Si) immediately following fabrication. One chamber remained uncoated throughout, and the last chamber was first tested without any coating, and then coated with a-Si following a series of heat treatments. The outgassing rate of each chamber was measured at room temperatures between 15 and 30 deg C following bakes at temperatures between 90 and 400 deg C. Measurements for bare steel showed a significant reduction in the outgassing rate by more than a factor of 20 after a 400 deg C heat treatment (3.5 x 10{sup 12} TorrL s{sup -1}cm{sup -2} prior to heat treatment, reduced to 1.7 x 10{ sup -13} TorrL s{sup -1}cm{sup -2} following heat treatment). The chambers that were coated with a-Si showed minimal change in outgassing rates with heat treatment, though an outgassing rate reduced by heat treatments prior to a-Si coating was successfully preserved throughout a series of bakes. The TiN coated chamber exhibited remarkably low outgassing rates, up to four orders of magnitude lower than the uncoated stainless steel. An evaluation of coating composition suggests the presence of elemental titanium which could provide pumping and lead to an artificially low outgassing rate. The outgassing results are discussed in terms of diffusion-limited versus recombination-limited processes.

  7. Assessment of CFD Hypersonic Turbulent Heating Rates for Space Shuttle Orbiter

    Science.gov (United States)

    Wood, William A.; Oliver, A. Brandon

    2011-01-01

    Turbulent CFD codes are assessed for the prediction of convective heat transfer rates at turbulent, hypersonic conditions. Algebraic turbulence models are used within the DPLR and LAURA CFD codes. The benchmark heat transfer rates are derived from thermocouple measurements of the Space Shuttle orbiter Discovery windward tiles during the STS-119 and STS-128 entries. The thermocouples were located underneath the reaction-cured glass coating on the thermal protection tiles. Boundary layer transition flight experiments conducted during both of those entries promoted turbulent flow at unusually high Mach numbers, with the present analysis considering Mach 10{15. Similar prior comparisons of CFD predictions directly to the flight temperature measurements were unsatisfactory, showing diverging trends between prediction and measurement for Mach numbers greater than 11. In the prior work, surface temperatures and convective heat transfer rates had been assumed to be in radiative equilibrium. The present work employs a one-dimensional time-accurate conduction analysis to relate measured temperatures to surface heat transfer rates, removing heat soak lag from the flight data, in order to better assess the predictive accuracy of the numerical models. The turbulent CFD shows good agreement for turbulent fuselage flow up to Mach 13. But on the wing in the wake of the boundary layer trip, the inclusion of tile conduction effects does not explain the prior observed discrepancy in trends between simulation and experiment; the flight heat transfer measurements are roughly constant over Mach 11-15, versus an increasing trend with Mach number from the CFD.

  8. Modeling the influence of potassium content and heating rate on biomass pyrolysis

    DEFF Research Database (Denmark)

    Trubetskaya, Anna; Surup, Gerrit; Shapiro, Alexander

    2017-01-01

    This study presents a combined kinetic and particle model that describes the effect of potassium and heating rate during the fast pyrolysis of woody and herbaceous biomass. The model calculates the mass loss rate, over a wide range of operating conditions relevant to suspension firing...

  9. Formation and sustainment of internal transport barriers in the International Thermonuclear Experimental Reactor with the baseline heating mix

    Energy Technology Data Exchange (ETDEWEB)

    Poli, Francesca M.; Kessel, Charles E. [Princeton Plasma Physics laboratory, Princeton, New Jersey 08543 (United States)

    2013-05-15

    Plasmas with internal transport barriers (ITBs) are a potential and attractive route to steady-state operation in ITER. These plasmas exhibit radially localized regions of improved confinement with steep pressure gradients in the plasma core, which drive large bootstrap current and generate hollow current profiles and negative magnetic shear. This work examines the formation and sustainment of ITBs in ITER with electron cyclotron heating and current drive. The time-dependent transport simulations indicate that, with a trade-off of the power delivered to the equatorial and to the upper launcher, the sustainment of steady-state ITBs can be demonstrated in ITER with the baseline heating configuration.

  10. Formation and sustainment of internal transport barriers in the International Thermonuclear Experimental Reactor with the baseline heating mixa)

    Science.gov (United States)

    Poli, Francesca M.; Kessel, Charles E.

    2013-05-01

    Plasmas with internal transport barriers (ITBs) are a potential and attractive route to steady-state operation in ITER. These plasmas exhibit radially localized regions of improved confinement with steep pressure gradients in the plasma core, which drive large bootstrap current and generate hollow current profiles and negative magnetic shear. This work examines the formation and sustainment of ITBs in ITER with electron cyclotron heating and current drive. The time-dependent transport simulations indicate that, with a trade-off of the power delivered to the equatorial and to the upper launcher, the sustainment of steady-state ITBs can be demonstrated in ITER with the baseline heating configuration.

  11. Influence of heating rate and temperature firing on the properties of bodies of red ceramic

    International Nuclear Information System (INIS)

    Silva, B.J. da; Goncalves, W.P.; Cartaxo, J.M.; Macedo, R.S.; Neves, G.A.; Santana, L.N.L.; Menezes, R.R.

    2011-01-01

    In the red ceramic industry, the firing is one of the main stages of the production process. There are two heating rates prevailing at this stage: the slow (traditional ceramics) and fast. The slow rate more used in Brazil, is considered delayed. This study aims to evaluate the influence of particle size and chemical composition of three mixture of clay, used in the manufacture of red ceramic products and to study the influence of the firing temperature on their technological properties. When subjected to heating rates slow and fast. Initially, the mixtures were characterized subsequently were extruded, dried and subjected to firing at temperatures of 900 and 1000 ° C with heating rates of 5, 20 and 30 °C/min. The results indicated that the chemical composition and particle size influenced significantly the technological properties and that the bodies obtained with the paste that had lower levels of flux showed better stability. (author)

  12. A quick, simplified approach to the evaluation of combustion rate from an internal combustion engine indicator diagram

    Directory of Open Access Journals (Sweden)

    Tomić Miroljub V.

    2008-01-01

    Full Text Available In this paper a simplified procedure of an internal combustion engine in-cylinder pressure record analysis has been presented. The method is very easy for programming and provides quick evaluation of the gas temperature and the rate of combustion. It is based on the consideration proposed by Hohenberg and Killman, but enhances the approach by involving the rate of heat transferred to the walls that was omitted in the original approach. It enables the evaluation of the complete rate of heat released by combustion (often designated as “gross heat release rate” or “fuel chemical energy release rate”, not only the rate of heat transferred to the gas (which is often designated as “net heat release rate”. The accuracy of the method has been also analyzed and it is shown that the errors caused by the simplifications in the model are very small, particularly if the crank angle step is also small. A several practical applications on recorded pressure diagrams taken from both spark ignition and compression ignition engine are presented as well.

  13. On-line tritium production and heat deposition rate measurements at the Lotus facility

    International Nuclear Information System (INIS)

    Joneja, O.P.; Scherrer, P.; Anand, R.P.

    1994-01-01

    Integral tritium production and heat deposition measurement in a prototype fusion blanket would enable verification of the computational codes and the data based employed for the calculations. A large number of tritium production rate measurements have been reported for different type of blankets, whereas the direct heat deposition due to the mixed radiation field in the fusion environment, is still in its infancy. In order to ascertain the kerma factors and the photon production libraries, suitable techniques must be developed to directly measure the nuclear heat deposition rates in the materials required for the fusion systems. In this context, at the Lotus facility, we have developed an extremely efficient double ionizing chamber, for the on-line tritium production measurements and employed a pure graphite calorimeter to measure the nuclear heat deposition due to the mixed radiation field of the 14 MeV, Haefely neutron generator. This paper presents both systems and some of the recent measurements. (authors). 8 refs., 13 figs

  14. First international workshop on fundamental aspects of post-dryout heat transfer: proceedings

    International Nuclear Information System (INIS)

    Lee, R.

    1984-12-01

    The purpose of the First International Workshop on Fundamental Aspects of Post-Dryout Heat Transfer was to review recent developments and the state of art in the field of post-dryout heat transfer. The workshop centered on interchanging ideas, reviewing current research results, and defining future research needs. The following five sessions dealing with the fundamental aspects of post-dryout heat transfer were held. A Computer Code Modeling and Flow Phenomena session was held dealing with flow rgimes, drop size, drop formation and behavior, interfacial area, interfacial drag, and computer modeling. A Quenching Phenomena session was held dealing with nature of rewetting, maximum wetting temperature, Leidenfrost phenomenon and heat transfer in the vicinity of quench front. A Low-Void Heat Transfer session was held dealing with inverted annular-flow heat transfer, inverted slug-flow heat transfer thermal non-equilibrium and computer modeling. A Dispersed-Flow Heat Transfer session was held dealing with drop interfacial heat transfer, vapor convection, thermal non-equilibrium and correlations and models

  15. Multi-boiling Heat Transfer Analysis of a Convective Straight Fin with Temperature-Dependent Thermal Properties and Internal Heat Generation

    Directory of Open Access Journals (Sweden)

    Gbeminiyi Sobamowo

    2017-10-01

    Full Text Available In this study, by using the finite volume method, the heat transfer in a convective straight fin with temperature-dependent thermal properties and an internal heat generation under multi-boiling heat transfer modes are analyzed. In this regard, the local heat transfer coefficient is considered to vary within a power-law function of temperature. In the present study, the coexistence of all the boiling modes is taken into consideration. The developed heat transfer models and the corresponding numerical solutions are used to investigate the effects of various thermo-geometric parameters on the thermal performance of the longitudinal rectangular fin. The results shows that the fin temperature distribution, the total heat transfer, and the fin efficiency are significantly affected by the thermo-geometric parameters of the fin and the internal heat generation within the fin. The obtained results can provide a platform for improvements in the design of the fin in the heat transfer equipment.

  16. Heat generation and cooling of SSC magnets at high ramp rates

    International Nuclear Information System (INIS)

    Snitchler, G.; Capone, D.; Kovachev, V.; Schermer, R.

    1992-01-01

    This presentation will address a summary of AC loss calculations (SSCL), experimental results on cable samples (Westinghouse STC), short model magnets test results (FNAL, KEK-Japan), and recent full length magnets test data on AC losses and quench current ramp rate sensitivity (FNAL, BNL). Possible sources of the observed enhanced heat generation and quench sensitivity for some magnets will be discussed. A model for cooling conditions of magnet coils considering heat generation distribution and specific anisotropy of the heat transfer will be presented. The crossover contact resistance in cables and curing procedure influence on resistivity, currently under study, will be briefly discussed. (author)

  17. Standard Test Method for Measuring Heat Transfer Rate Using a Thin-Skin Calorimeter

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2005-01-01

    1.1 This test method covers the design and use of a thin metallic calorimeter for measuring heat transfer rate (also called heat flux). Thermocouples are attached to the unexposed surface of the calorimeter. A one-dimensional heat flow analysis is used for calculating the heat transfer rate from the temperature measurements. Applications include aerodynamic heating, laser and radiation power measurements, and fire safety testing. 1.2 Advantages 1.2.1 Simplicity of ConstructionThe calorimeter may be constructed from a number of materials. The size and shape can often be made to match the actual application. Thermocouples may be attached to the metal by spot, electron beam, or laser welding. 1.2.2 Heat transfer rate distributions may be obtained if metals with low thermal conductivity, such as some stainless steels, are used. 1.2.3 The calorimeters can be fabricated with smooth surfaces, without insulators or plugs and the attendant temperature discontinuities, to provide more realistic flow conditions for ...

  18. 76 FR 65639 - International Mail: Proposed Product Rate and Fee Changes

    Science.gov (United States)

    2011-10-24

    ... Customs Clearance and Delivery Fee International Reply Coupons International Business Reply Service The... * * * * * International Business Reply Service (382) [For each country that offers International Business Reply Service... POSTAL SERVICE 39 CFR Part 20 International Mail: Proposed Product Rate and Fee Changes AGENCY...

  19. Heat-resistant materials 2. Conference proceedings of the 2. international conference on heat-resistant materials

    International Nuclear Information System (INIS)

    Natesan, K.; Ganesan, P.; Lai, G.Y.

    1995-01-01

    The Second International Conference on Heat-Resistant Materials was held in Gatlinburg, Tennessee, September 11--14, 1995 and focused on materials performance in cross-cutting technologies where heat resistant materials play a large and sometimes life-and performance-limiting roles in process schemes. The scope of materials for heat-resistant applications included structural iron- and nickel-base alloys, intermetallics, and ceramics. The conference focused on materials development, performance of materials in simulated laboratory and actual service environments on mechanical and structural integrity of components, and state-of-the-art techniques for processing and evaluating materials performance. The three keynote talks described the history of heat-resistant materials, relationship between microstructure and mechanical behavior, and applications of these materials in process schemes. The technical sessions included alloy metallurgy and properties, environmental effects and properties, deformation behavior and properties, relation between corrosion and mechanical properties, coatings, intermetallics, ceramics, and materials for waste incineration. Seventy one papers have been processed separately for inclusion on the data base

  20. Effect of tunnel cross section on gas temperatures and heat fluxes in case of large heat release rate

    International Nuclear Information System (INIS)

    Fan, Chuan Gang; Li, Ying Zhen; Ingason, Haukur; Lönnermark, Anders

    2016-01-01

    Highlights: • The effect of tunnel cross section together with ventilation velocity was studied. • Ceiling temperature varies clearly with tunnel height, but little with tunnel width. • Downstream temperature decreases with increasing tunnel dimensions. • HRR is an important factor that influences decay rate of excess gas temperature. • An equation considering both tunnel dimensions and HRR was developed. - Abstract: Tests with liquid and solid fuels in model tunnels (1:20) were performed and analysed in order to study the effect of tunnel cross section (width and height) together with ventilation velocity on ceiling gas temperatures and heat fluxes. The model tunnel was 10 m long with varying width (0.3 m, 0.45 m and 0.6 m) and height (0.25 m and 0.4 m). Test results show that the maximum temperature under the ceiling is a weak function of heat release rate (HRR) and ventilation velocity for cases with HRR more than 100 MW at full scale. It clearly varies with the tunnel height and is a weak function of the tunnel width. With a lower tunnel height, the ceiling is closer to the base of continuous flame zone and the temperatures become higher. Overall, the gas temperature beneath the ceiling decreases with the increasing tunnel dimensions, and increases with the increasing longitudinal ventilation velocity. The HRR is also an important factor that influences the decay rate of excess gas temperature, and a dimensionless HRR integrating HRR and other two key parameters, tunnel cross-sectional area and distance between fuel centre and tunnel ceiling, was introduced to account for the effect. An equation for the decay rate of excess gas temperature, considering both the tunnel dimensions and HRR, was developed. Moreover, a larger tunnel cross-sectional area will lead to a smaller heat flux.

  1. Estimation of fuel burning rate and heating value with highly variable properties for optimum combustion control

    International Nuclear Information System (INIS)

    Hsi, C.-L.; Kuo, J.-T.

    2008-01-01

    Estimating solid residue gross burning rate and heating value burning in a power plant furnace is essential for adequate manipulation to achieve energy conversion optimization and plant performance. A model based on conservation equations of mass and thermal energy is established in this work to calculate the instantaneous gross burning rate and lower heating value of solid residue fired in a combustion chamber. Comparing the model with incineration plant control room data indicates that satisfactory predictions of fuel burning rates and heating values can be obtained by assuming the moisture-to-carbon atomic ratio (f/a) within the typical range from 1.2 to 1.8. Agreement between mass and thermal analysis and the bed-chemistry model is acceptable. The model would be useful for furnace fuel and air control strategy programming to achieve optimum performance in energy conversion and pollutant emission reduction

  2. Heat rate curve approximation for power plants without data measuring devices

    Energy Technology Data Exchange (ETDEWEB)

    Poullikkas, Andreas [Electricity Authority of Cyprus, P.O. Box 24506, 1399 Nicosia (CY

    2012-07-01

    In this work, a numerical method, based on the one-dimensional finite difference technique, is proposed for the approximation of the heat rate curve, which can be applied for power plants in which no data acquisition is available. Unlike other methods in which three or more data points are required for the approximation of the heat rate curve, the proposed method can be applied when the heat rate curve data is available only at the maximum and minimum operating capacities of the power plant. The method is applied on a given power system, in which we calculate the electricity cost using the CAPSE (computer aided power economics) algorithm. Comparisons are made when the least squares method is used. The results indicate that the proposed method give accurate results.

  3. Molecular dynamics simulations of aggregation of copper nanoparticles with different heating rates

    Science.gov (United States)

    Li, Qibin; Wang, Meng; Liang, Yunpei; Lin, Liyang; Fu, Tao; Wei, Peitang; Peng, Tiefeng

    2017-06-01

    Molecular dynamics simulations were employed to investigate the heating rates' effect on aggregation of two copper nanoparticles. The aggregation can be distinguished into three distinct regimes by the contacting and melting of nanoparticles. The nanoparticles contacting at a lower temperature during the sintering with lower heating rate, meanwhile, some temporary stacking fault exists at the contacting neck. The aggregation properties of the system, i.e. neck diameter, shrinkage ratio, potential energy, mean square displacement (MSD) and relative gyration radius, experience drastic changes due to the free surface annihilation. After the nanoparticles coalesced for a stable period, the shrinkage ratio, MSD, relative gyration radius and neck diameter of the system are dramatically changed during the melting process. It is shown that the shrinkage ratio and MSD have relative larger increasing ratio for a lower heating rate. While the evolution of the relative gyration radius and neck diameter is only sensitive to the temperature.

  4. Influence of Strain Rate on Heat Release under Quasi-Static Stretching of Metals. Experiment

    Science.gov (United States)

    Zimin, B. A.; Sventitskaya, V. E.; Smirnov, I. V.; Sud'enkov, Yu. V.

    2018-04-01

    The paper presents the results of experimental studies of energy dissipation during a quasi-static stretching of metals and alloys at room temperature. The strain rates varied in the range of 10-3-10-2 s-1. Samples of M1 copper, AZ31B magnesium alloy, BT6 titanium, 12Cr18Ni10Ti steel, and D16AM aluminum alloy were analyzed. The experimental results demonstrated a significant dependence of the heat release on the strain rate in the absence of its influence on stress-strain diagrams for all the metals studied in this range of strain rates. The correlation of the changes in the character of heat release with the processes of structural transformations at various stages of plastic flow is shown on the qualitative level. A difference in the nature of the processes of heat release in materials with different ratios of the plasticity and strength is noted.

  5. Metallic materials for heat exchanger components and highly stressed internal of HTR reactors for nuclear process heat generation

    International Nuclear Information System (INIS)

    1982-01-01

    The programme was aimed at the development and improvement of materials for the high-temperature heat exchanger components of a process steam HTR. The materials must have high resistance to corrosion, i.e. carburisation and internal oxidation, and high long-term toughness over a wide range of temperatures. They must also meet the requirements set in the nuclear licensing procedure, i.e. resistance to cyclic stress and irradiation, non-destructive testing, etc. Initially, it was only intended to improve and qualify commercial alloys. Later on an alloy development programme was initiated in which new, non-commercial alloys were produced and modified for use in a nuclear process heat facility. Separate abstracts were prepared for 19 pays of this volume. (orig./IHOE) [de

  6. Effects of heating rate on slow pyrolysis behavior, kinetic parameters and products properties of moso bamboo.

    Science.gov (United States)

    Chen, Dengyu; Zhou, Jianbin; Zhang, Qisheng

    2014-10-01

    Effects of heating rate on slow pyrolysis behaviors, kinetic parameters, and products properties of moso bamboo were investigated in this study. Pyrolysis experiments were performed up to 700 °C at heating rates of 5, 10, 20, and 30 °C/min using thermogravimetric analysis (TGA) and a lab-scale fixed bed pyrolysis reactor. The results show that the onset and offset temperatures of the main devolatilization stage of thermogravimetry/derivative thermogravimetry (TG/DTG) curves obviously shift toward the high-temperature range, and the activation energy values increase with increasing heating rate. The heating rate has different effects on the pyrolysis products properties, including biochar (element content, proximate analysis, specific surface area, heating value), bio-oil (water content, chemical composition), and non-condensable gas. The solid yields from the fixed bed pyrolysis reactor are noticeably different from those of TGA mainly because the thermal hysteresis of the sample in the fixed bed pyrolysis reactor is more thorough. Copyright © 2014 Elsevier Ltd. All rights reserved.

  7. Myowater dynamics and protein secondary structural changes as affected by heating rate in three pork qualities: a combined FT-IR microspectroscopic and 1H NMR relaxometry study.

    Science.gov (United States)

    Wu, Zhiyun; Bertram, Hanne Christine; Böcker, Ulrike; Ofstad, Ragni; Kohler, Achim

    2007-05-16

    The objective of this study was to investigate the influence of heating rate on myowater dynamics and protein secondary structures in three pork qualities by proton NMR T2 relaxation and Fourier transform infrared (FT-IR) microspectroscopy measurements. Two oven temperatures at 100 degrees C and 200 degrees C corresponding to slow and fast heating rates were applied on three pork qualities (DFD, PSE, and normal) to an internal center temperature of 65 degrees C. The fast heating induced a higher cooking loss, particularly for PSE meat. The water proton T21 distribution representing water entrapped within the myofibrillar network was influenced by heating rate and meat quality. Fast heating broadened the T21 distribution and decreased the relaxation times of the T21 peak position for three meat qualities. The changes in T21 relaxation times in meat can be interpreted in terms of chemical and diffusive exchange. FT-IR showed that fast heating caused a higher gain of random structures and aggregated beta-sheets at the expense of native alpha-helixes, and these changes dominate the fast-heating-induced broadening of T21 distribution and reduction in T21 times. Furthermore, of the three meat qualities, PSE meat had the broadest T21 distribution and the lowest T21 times for both heating rates, reflecting that the protein aggregation of PSE caused by heating is more extensive than those of DFD and normal, which is consistent with the IR data. The present study demonstrated that the changes in T2 relaxation times of water protons affected by heating rate and raw meat quality are well related to the protein secondary structural changes as probed by FT-IR microspectroscopy.

  8. A real-time heat strain risk classifier using heart rate and skin temperature

    International Nuclear Information System (INIS)

    Buller, Mark J; Latzka, William A; Yokota, Miyo; Tharion, William J; Moran, Daniel S

    2008-01-01

    Heat injury is a real concern to workers engaged in physically demanding tasks in high heat strain environments. Several real-time physiological monitoring systems exist that can provide indices of heat strain, e.g. physiological strain index (PSI), and provide alerts to medical personnel. However, these systems depend on core temperature measurement using expensive, ingestible thermometer pills. Seeking a better solution, we suggest the use of a model which can identify the probability that individuals are 'at risk' from heat injury using non-invasive measures. The intent is for the system to identify individuals who need monitoring more closely or who should apply heat strain mitigation strategies. We generated a model that can identify 'at risk' (PSI ≥ 7.5) workers from measures of heart rate and chest skin temperature. The model was built using data from six previously published exercise studies in which some subjects wore chemical protective equipment. The model has an overall classification error rate of 10% with one false negative error (2.7%), and outperforms an earlier model and a least squares regression model with classification errors of 21% and 14%, respectively. Additionally, the model allows the classification criteria to be adjusted based on the task and acceptable level of risk. We conclude that the model could be a valuable part of a multi-faceted heat strain management system. (note)

  9. Relationship between ash content and R{sub 70} self-heating rate of Callide Coal

    Energy Technology Data Exchange (ETDEWEB)

    Beamish, B. Basil; Blazak, Darren G. [School of Engineering, The University of Queensland, St Lucia, Qld 4072 (Australia)

    2005-10-17

    Borecore samples from the Trap Gully pit at Callide have been assessed using the R{sub 70} self-heating test. The highest R{sub 70} self-heating rate value was 16.22 {sup o}C/h, which is consistent with the subbituminous rank of the coal. R{sub 70} decreases significantly with increasing mineral matter content, as defined by the ash content of the coal. This effect is due to the mineral matter in the coal acting as a heat sink. A trendline equation has been fitted to the borecore data from the Trap Gully pit: R{sub 70}=0.0029xash{sup 2}-0.4889xash+20.644, where all parameters are on a dry-basis. This relationship can be used to model the self-heating hazard of the pit, both vertically and laterally. (author)

  10. Comparison of Marginal and Internal Adaptation of Heat-Pressed and CAD/CAM Porcelain Laminate Veneers and a 2-Year Follow-Up.

    Science.gov (United States)

    Yuce, Mert; Ulusoy, Mubin; Turk, Ayse Gozde

    2017-12-22

    To compare marginal and internal adaptations of porcelain laminate veneers fabricated with heat-pressed and CAD/CAM techniques, and to evaluate the clinical performances 2 years after cementation. Thirty heat-pressed and 31 CAD/CAM porcelain laminate veneers were fabricated for 12 patients. Silicone replicas of each veneer were obtained. Replicas were sectioned into 4 parts to measure adaptations of the veneers. A stereomicroscope was used to measure from 3 locations of replicas for marginal, and 9 locations for internal adaptations at 40x magnification. Clinical evaluations were done at baseline and 6, 12, 18, and 24 months after cementation according to the modified United States Public Health Service (USPHS) criteria. Independent samples t-test compared the adaptation values between heat-pressed and CAD/CAM groups. Paired t-test was used to evaluate marginal and internal adaptations of each group. Differences between the modified USPHS criteria ratings of heat-pressed and CAD/CAM groups were determined by the Mann-Whitney U test. Kaplan-Meier analysis was used to analyze the survival ratings of the veneers (p CAD/CAM veneers were 295 and 314.98 μm, respectively, and there was no statistically significant difference (p = 0.541). Internal adaptation values of groups were not statistically different either (201.82 μm for heat pressed; 195.47 μm for CAD/CAM p = 0.734). When marginal and internal adaptation values were compared within groups, there were significant differences both for heat-pressed (p CAD/CAM (p CAD/CAM or heat-pressed, had no effect on the marginal and internal adaptation of porcelain laminate veneers. The results showed that both fabrication techniques performed well after 2 years of clinical performance. © 2017 by the American College of Prosthodontists.

  11. Controlling the Internal Heat Transfer Coefficient by the Characteristics of External Flows

    Science.gov (United States)

    Zhuromskii, V. M.

    2018-01-01

    The engineering-physical fundamentals of substance synthesis in a boiling apparatus are presented. We have modeled a system of automatic stabilization of the maximum internal heat transfer coefficient in such an apparatus by the characteristics of external flows on the basis of adaptive seeking algorithms. The results of operation of the system in the shop are presented.

  12. Finite element simulation of internal flows with heat transfer using a ...

    Indian Academy of Sciences (India)

    Unknown

    Velocity correction method; finite element simulation; turbulent .... CFD, developments in turbulence modeling have been only evolutionary and ...... variables are made dimensionless using appropriate combinations of Uav, H, ...... Srinivas M 1994 Finite element analysis of internal flows with heat transfer Ph D thesis, Indian.

  13. Measurement of specific heat and specific absorption rate by nuclear magnetic resonance

    Energy Technology Data Exchange (ETDEWEB)

    Gultekin, David H., E-mail: david.gultekin@aya.yale.edu [Department of Electrical Engineering, Yale University, New Haven, CT 06520 (United States); Department of Medical Physics, Memorial Sloan-Kettering Cancer Center, New York, NY 10065 (United States); Department of Radiology, Memorial Sloan-Kettering Cancer Center, New York, NY 10065 (United States); Institute of Imaging Science, Vanderbilt University, Nashville, TN 37232 (United States); Gore, John C. [Department of Biomedical Engineering, Vanderbilt University, Nashville, TN 37232 (United States); Department of Radiology and Radiological Sciences, Vanderbilt University, Nashville, TN 37232 (United States); Department of Molecular Physiology and Biophysics, Vanderbilt University, Nashville, TN 37232 (United States); Department of Physics and Astronomy, Vanderbilt University, Nashville, TN 37232 (United States); Institute of Imaging Science, Vanderbilt University, Nashville, TN 37232 (United States)

    2010-05-20

    We evaluate a nuclear magnetic resonance (NMR) method of calorimetry for the measurement of specific heat (c{sub p}) and specific absorption rate (SAR) in liquids. The feasibility of NMR calorimetry is demonstrated by experimental measurements of water, ethylene glycol and glycerol using any of three different NMR parameters (chemical shift, spin-spin relaxation rate and equilibrium nuclear magnetization). The method involves heating the sample using a continuous wave laser beam and measuring the temporal variation of the spatially averaged NMR parameter by non-invasive means. The temporal variation of the spatially averaged NMR parameter as a function of thermal power yields the ratio of the heat capacity to the respective nuclear thermal coefficient, from which the specific heat can be determined for the substance. The specific absorption rate is obtained by subjecting the liquid to heating by two types of radiation, radiofrequency (RF) and near-infrared (NIR), and by measuring the change in the nuclear spin phase shift by a gradient echo imaging sequence. These studies suggest NMR may be a useful tool for measurements of the thermal properties of liquids.

  14. Study of the Al-Si-X system by different cooling rates and heat treatment

    Directory of Open Access Journals (Sweden)

    Miguel Angel Suarez

    2012-10-01

    Full Text Available The solidification behavior of the Al-12.6% Si (A1, the hypereutectic Al-20%Si (A2 and the Al-20%Si-1.5% Fe-0.5%Mn (A3 (in wt. (% alloys, at different cooling rates is reported and discussed. The cooling rates ranged between 0.93 °C/s and 190 °C/s when cast in sand and copper wedge-shaped molds, respectively. A spheroidization heat treatment was carried out to the alloys in the as-cast condition at 540 °C for 11 hours and quench in water with a subsequent heat treatment at 170 °C for 5 hours with the purpose of improving the mechanical properties. The samples were characterized by optical microscopy, scanning electron microscopy and mechanically by tensile test, in order to evaluate the response of the heat treatment on the different starting microstructures and mechanical properties. It was found that alloys cooled at rates greater than 10.8 °C/s had a smaller particle size and better distribution, also showed a greater response to spheroidization heat treatment of all silicon (Si phases. The spheroidization heat treatment caused an increase in the ultimate tensile stress (UTS and elongation when compared with the alloys in the as-cast condition. The highest UTS value of 174 MPa was obtained for the (A1 alloy.

  15. Control strategy on the double-diffusive convection in a nanofluid layer with internal heat generation

    Science.gov (United States)

    Mokhtar, N. F. M.; Khalid, I. K.; Siri, Z.; Ibrahim, Z. B.; Gani, S. S. A.

    2017-10-01

    The influences of feedback control and internal heat source on the onset of Rayleigh-Bénard convection in a horizontal nanofluid layer is studied analytically due to Soret and Dufour parameters. The confining boundaries of the nanofluid layer (bottom boundary-top boundary) are assumed to be free-free, rigid-free, and rigid-rigid, with a source of heat from below. Linear stability theory is applied, and the eigenvalue solution is obtained numerically using the Galerkin technique. Focusing on the stationary convection, it is shown that there is a positive thermal resistance in the presence of feedback control on the onset of double-diffusive convection, while there is a positive thermal efficiency in the existence of internal heat generation. The possibilities of suppress or augment of the Rayleigh-Bénard convection in a nanofluid layer are also discussed in detail.

  16. Design and evaluation of heat utilization systems for the HTTR through international cooperation

    Energy Technology Data Exchange (ETDEWEB)

    Lewkowicz, I. [International Atomic Energy Agency, Vienna (Austria)

    1996-07-01

    The International Atomic Energy Agency (IAEA) has the statutory function to `foster the exchange of scientific and technical information`, and `encourage and assist research on, and development and practical application of, atomic energy for peaceful uses throughout the world`. The IAEA Co-ordinated Research Programmes (CRPs) are effective vehicles for implementing the above. The CRP on Design and Evaluation of Heat Utilization Systems for HTTR has started in September 1994 and is aimed at promoting international co-operation to identify the most promising heat utilization system(s) to be demonstrated at the HTTR, for the benefit of current operators and future designers and constructors of HTGRs. Participating Member States are collaborating by exchanging existing technical information on the technology of heat utilization systems, by developing design concepts and by performing evaluations of candidate systems for potential demonstration with the HTTR. In this report, the systems are reviewed. (J.P.N.)

  17. AN EXPERIMENTAL STUDY ON A VAPOR COMPRESSION REFRIGERATION CYCLE BY ADDING INTERNAL HEAT EXCHANGER

    Directory of Open Access Journals (Sweden)

    Muhammad Asmail Eleiwi

    2013-05-01

    Full Text Available Thispaper presents practical study to improve the indication COP of a vaporcompression refrigeration cycle in instrumented automobile air conditioner bydesigning internal heat exchanger and installing it in the vapor compressionrefrigeration cycle.  Two cases of  vapor compression refrigeration cycle were takenin this paper:  the first case is thatthe vapor compression refrigeration cycle without internal heat exchanger andin  the second case the vapor compressionrefrigeration cycle with heat exchanger ; in these two cases, the temperatureat each point of  a vapor compressionrefrigeration cycle, the low and the high pressure ,the indoor temperature andthe outdoor temperature were measured at each time at compressor speed 1450 rpmand 2900 rpm for each blower speed 1, blower speed 2 and blower speed 3.Therefrigerant fluid was used in the vapor compression refrigeration cycle withoutIHE and with IHE is R134a..

  18. Design and evaluation of heat utilization systems for the HTTR through international cooperation

    International Nuclear Information System (INIS)

    Lewkowicz, I.

    1996-01-01

    The International Atomic Energy Agency (IAEA) has the statutory function to 'foster the exchange of scientific and technical information', and 'encourage and assist research on, and development and practical application of, atomic energy for peaceful uses throughout the world'. The IAEA Co-ordinated Research Programmes (CRPs) are effective vehicles for implementing the above. The CRP on Design and Evaluation of Heat Utilization Systems for HTTR has started in September 1994 and is aimed at promoting international co-operation to identify the most promising heat utilization system(s) to be demonstrated at the HTTR, for the benefit of current operators and future designers and constructors of HTGRs. Participating Member States are collaborating by exchanging existing technical information on the technology of heat utilization systems, by developing design concepts and by performing evaluations of candidate systems for potential demonstration with the HTTR. In this report, the systems are reviewed. (J.P.N.)

  19. Dual Rate Adaptive Control for an Industrial Heat Supply Process Using Signal Compensation Approach

    Energy Technology Data Exchange (ETDEWEB)

    Chai, Tianyou; Jia, Yao; Wang, Hong; Su, Chun-Yi

    2017-07-09

    The industrial heat supply process (HSP) is a highly nonlinear cascaded process which uses a steam valve opening as its control input, the steam flow-rate as its inner loop output and the supply water temperature as its outer loop output. The relationship between the heat exchange rate and the model parameters, such as steam density, entropy, and fouling correction factor and heat exchange efficiency are unknown and nonlinear. Moreover, these model parameters vary in line with steam pressure, ambient temperature and the residuals caused by the quality variations of the circulation water. When the steam pressure and the ambient temperature are of high values and are subjected to frequent external random disturbances, the supply water temperature and the steam flow-rate would interact with each other and fluctuate a lot. This is also true when the process exhibits unknown characteristic variations of the process dynamics caused by the unexpected changes of the heat exchange residuals. As a result, it is difficult to control the supply water temperature and the rates of changes of steam flow-rate well inside their targeted ranges. In this paper, a novel compensation signal based dual rate adaptive controller is developed by representing the unknown variations of dynamics as unmodeled dynamics. In the proposed controller design, such a compensation signal is constructed and added onto the control signal obtained from the linear deterministic model based feedback control design. Such a compensation signal aims at eliminating the unmodeled dynamics and the rate of changes of the currently sample unmodeled dynamics. A successful industrial application is carried out, where it has been shown that both the supply water temperature and the rate of the changes of the steam flow-rate can be controlled well inside their targeted ranges when the process is subjected to unknown variations of its dynamics.

  20. 77 FR 72960 - International Mail: Product Rate and Fee Changes

    Science.gov (United States)

    2012-12-07

    ..., English, Arabic, Chinese, Spanish, and/ or Russian. 381.2 Previously Sold Coupons and Exchange Value The... postage validation imprinter (PVI) label, and dispatch it to the appropriate International Service Center...

  1. Logistics: DoD International Personal Property Shipment Rates

    National Research Council Canada - National Science Library

    2002-01-01

    ... all or most of the cargo space available on U.S.-flag vessels and subsequently resold the space at an inflated price to selected freight forwarders that participated in the DoD International Personal Property Program...

  2. Average Heating Rate of Hot Atmospheres in Distant Galaxy Clusters by Radio AGN: Evidence for Continuous AGN Heating

    Science.gov (United States)

    Ma, Cheng-Jiun; McNamara, B.; Nulsen, P.; Schaffer, R.

    2011-09-01

    X-ray observations of nearby clusters and galaxies have shown that energetic feedback from AGN is heating hot atmospheres and is probably the principal agent that is offsetting cooling flows. Here we examine AGN heating in distant X-ray clusters by cross correlating clusters selected from the 400 Square Degree X-ray Cluster survey with radio sources in the NRAO VLA Sky Survey. The jet power for each radio source was determined using scaling relations between radio power and cavity power determined for nearby clusters, groups, and galaxies with atmospheres containing X-ray cavities. Roughly 30% of the clusters show radio emission above a flux threshold of 3 mJy within the central 250 kpc that is presumably associated with the brightest cluster galaxy. We find no significant correlation between radio power, hence jet power, and the X-ray luminosities of clusters in redshift range 0.1 -- 0.6. The detection frequency of radio AGN is inconsistent with the presence of strong cooling flows in 400SD, but cannot rule out the presence of weak cooling flows. The average jet power of central radio AGN is approximately 2 10^{44} erg/s. The jet power corresponds to an average heating of approximately 0.2 keV/particle for gas within R_500. Assuming the current AGN heating rate remained constant out to redshifts of about 2, these figures would rise by a factor of two. Our results show that the integrated energy injected from radio AGN outbursts in clusters is statistically significant compared to the excess entropy in hot atmospheres that is required for the breaking of self-similarity in cluster scaling relations. It is not clear that central AGN in 400SD clusters are maintained by a self-regulated feedback loop at the base of a cooling flow. However, they may play a significant role in preventing the development of strong cooling flows at early epochs.

  3. Study of entropy generation in a slab with non-uniform internal heat generation

    Directory of Open Access Journals (Sweden)

    El Haj Assad Mamdouh

    2013-01-01

    Full Text Available Analysis of entropy generation in a rectangular slab with a nonuniform internal heat generation is presented. Dimensionless local and total entropy generation during steady state heat conduction through the slab are obtained. Two different boundary conditions have been considered in the analysis, the first with asymmetric convection and the second with constant slab surface temperature. Temperature distribution within the slab is obtained analytically. The study investigates the effect of some relevant dimensionless heat transfer parameters on entropy generation. The results show that there exists a minimum local entropy generation but there does not exist a minimum total entropy generation for certain combinations of the heat transfer parameters. The results of calculations are presented graphically.

  4. Influence of internal channel geometry of gas turbine blade on flow structure and heat transfer

    Science.gov (United States)

    Szwaba, Ryszard; Kaczynski, Piotr; Telega, Janusz; Doerffer, Piotr

    2017-12-01

    This paper presents the study of the influence of channel geometry on the flow structure and heat transfer, and also their correlations on all the walls of a radial cooling passage model of a gas turbine blade. The investigations focus on the heat transfer and aerodynamic measurements in the channel, which is an accurate representation of the configuration used in aeroengines. Correlations for the heat transfer coefficient and the pressure drop used in the design of internal cooling passages are often developed from simplified models. It is important to note that real engine passages do not have perfect rectangular cross sections, but include a corner fillets, ribs with fillet radii and a special orientation. Therefore, this work provides detailed fluid flow and heat transfer data for a model of radial cooling geometry which has very realistic features.

  5. Calculation of heat rating and burn-up for test fuel pins irradiated in DR 3

    International Nuclear Information System (INIS)

    Bagger, C.; Carlsen, H.; Hansen, K.

    1980-01-01

    A summary of the DR 3 reactor and HP1 rig design is given followed by a detailed description of the calculation procedure for obtaining linear heat rating and burn-up values of fuel pins irradiated in HP1 rigs. The calculations are carried out rather detailed, especially regarding features like end pellet contribution to power as a function of burn-up, gamma heat contributions, and evaluation of local values of heat rating and burn-up. Included in the report is also a description of the fast flux- and cladding temperature calculation techniques currently used. A good agreement between measured and calculated local burn-up values is found. This gives confidence to the detailed treatment of the data. (author)

  6. Critical heat flux analysis on change of plate temperature and cooling water flow rate for rectangular narrow gap with bilateral-heated cases

    International Nuclear Information System (INIS)

    M Hadi Kusuma; Mulya Juarsa; Anhar Riza Antariksawan

    2013-01-01

    Boiling heat transfer phenomena on rectangular narrow gap was related to the safety of nuclear reactors. Research done in order to study the safety of nuclear reactors in particular relating to boiling heat transfer and useful on the improvement of next-generation reactor designs. The research focused on calculation of the heat flux during the cooling process in rectangular narrow gap size 1.0 mm. with initial temperatures 200°C. 400°C, and 600°C, also the flow rates of cooling water 0,1 liters/second. 0,2 liters/second. and 0,3 liters/second. Experiments carried out by injecting water at a certain flow rate with the water temperature 85°C. Transient temperature measurement data recorded by the data acquisition system. Transient temperature measurement data is used to calculate the flux of heat gain is then used to obtain the heat transfer coefficient. This research aimed to obtain the correlation between critical heat flux and heat transfer coefficient to changes in temperatures and water flow rates for bilaterally-heated cases on rectangular narrow gap. The results obtained for a constant cooling water flow rate, critical heat flux will increase when hot plate temperature also increased. While on a constant hot plate temperature, coefficient heat transfer will increase when cooling water flow rate also increased. Thus it can be said that the cooling water flow rate and temperature of the hot plate has a significant effect on the critical heat flux and heat transfer coefficient resulted in quenching process of vertical rectangular narrow gap with double-heated cases. (author)

  7. Experimental investigations of heat transfer from an internally finned two phase closed thermosyphon

    International Nuclear Information System (INIS)

    Naresh, Y.; Balaji, C.

    2017-01-01

    Highlights: • Experimental investigations on an internally finned vertical thermosyphon. • Two fluids – water and acetone considered. • Optimum fill ratio determined to be 50%. • Addition of internal fins at the condenser leads to improved thermal performance. - Abstract: This paper reports the results of an experimental investigation of heat transfer from an internally finned thermosyphon charged with either water or acetone. Six constant area fins with a rectangular cross section are placed internally along the length at the condenser section. The ratio of initial liquid pool volume to the evaporator volume, known as the filling ratio in a thermosyphon system, has been varied in this study. Experiments are carried out for filling ratios of 20, 50, and 80% for two working fluids (i) water and (ii) acetone. Results show that a fill ratio of 50% gives better heat transfer performance. Providing internal fins at the condenser produces additional condensation which improves the thermal performance of the thermosyphon by 17% in terms of the temperature reduction at the source and sink and 35.48% in terms of reduction in thermal resistance at lower heat inputs. The thermosyphon is tested between power levels of 50 and 275 W.

  8. 40 CFR 75.83 - Calculation of Hg mass emissions and heat input rate.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 16 2010-07-01 2010-07-01 false Calculation of Hg mass emissions and... (CONTINUED) AIR PROGRAMS (CONTINUED) CONTINUOUS EMISSION MONITORING Hg Mass Emission Provisions § 75.83 Calculation of Hg mass emissions and heat input rate. The owner or operator shall calculate Hg mass emissions...

  9. Thermoluminescent response of LiF before variation of the heating rate

    International Nuclear Information System (INIS)

    Barrios, R.; Avila, O.

    2003-01-01

    Comparisons of glow curves of lithium fluoride dosemeters TLD-100 measured to two heating rates with the purpose of quantifying the change in the temperature of the peaks 5 and 7 for the thermoluminescent reader equipment Harshaw 4000 of the thermoluminescence laboratory of the ININ were carried out. (Author)

  10. Effect of pyrolysis pressure and heating rate on radiata pine char structure and apparent gasification reactivity

    Energy Technology Data Exchange (ETDEWEB)

    E. Cetin; R. Gupta; B. Moghtaderi [University of Newcastle, Callaghan, NSW (Australia). Discipline of Chemical Engineering, Faculty of Engineering and Built Environment, School of Engineering

    2005-07-01

    The knowledge of biomass char gasification kinetics has considerable importance in the design of advanced biomass gasifiers, some of which operate at high pressure. The char gasification kinetics themselves are influenced by char structure. In this study, the effects of pyrolysis pressure and heating rate on the char structure were investigated using scanning electron microscopy (SEM) analysis, digital cinematography, and surface area analysis. Char samples were prepared at pressures between 1 and 20 bar, temperatures ranging from 800 to 1000{degree}C, and heating rates between 20 and 500{degree}C/s. Our results indicate that pyrolysis conditions have a notable impact on the biomass char morphology. Pyrolysis pressure, in particular, was found to influence the size and the shape of char particles while high heating rates led to plastic deformation of particles (i.e. melting) resulting in smooth surfaces and large cavities. The global gasification reactivities of char samples were also determined using thermogravimetric analysis (TGA) technique. Char reactivities were found to increase with increasing pyrolysis heating rates and decreasing pyrolysis pressure. 22 refs., 8 figs., 2 tabs.

  11. Experimental study of humidity distribution inside electronic enclosure and effect of internal heating

    DEFF Research Database (Denmark)

    Conseil, Helene; Jellesen, Morten Stendahl; Ambat, Rajan

    2016-01-01

    on the humidity and temperature profile inside typical electronic enclosures. Defined parameters include external temperature and humidity conditions, temperature and time of the internal heat cycle, thermal mass, and ports/openings size. The effect of the internal humidity on electronic reliability has been......Corrosion reliability of electronic products is a key factor for electronics industry, and today there is a large demand for performance reliability in a wide range of temperature and humidity during day and night time periods. Corrosion failures are still a challenge due to the combined effects...... of temperature, humidity and corrosion accelerating species in the atmosphere. Moreover the surface region of printed circuit board assemblies is often contaminated by various aggressive chemical species.This study describes the overall effect of the exposure to severe climate conditions and internal heat cycles...

  12. Social Policy Trends: International Trends in Female Employment Rates

    Directory of Open Access Journals (Sweden)

    Ronald D. Kneebone

    2018-02-01

    Full Text Available Women are playing a larger role in the workforce than ever before, but not in the U.S. The employment rate measures the percentage of the adult population of working age (15-64 years that is an active participant in the labour force (full-time or part-time. A high employment rate enables countries to finance government programs with moderate rates of taxation, and in high employment countries there tends to be less pressure on social programs. Countries with low employment rates are less able to fund services and face greater social pressures.The employment rate provides a better measure of economic performance than the unemployment rate because it considers not only individuals who are unemployed but also those who have been discouraged to look for work.

  13. Results of out-of-pile experiments to investigate the possibilities of cooling a core melt with internal heat production

    International Nuclear Information System (INIS)

    Fieg, G.

    1976-01-01

    After serious hypothetical reactor accidents, melted core materials with internal heat production can occur in large quantities. A retention of these molten core masses within the containment must be ensured. The knowledge of the heat transport from volume-heated layers is necessary to clarify this matter. (orig./LH) [de

  14. Performance investigation on a 4-bed adsorption desalination cycle with internal heat recovery scheme

    KAUST Repository

    Thu, Kyaw

    2016-10-08

    Multi-bed adsorption cycle with the internal heat recovery between the condenser and the evaporator is investigated for desalination application. A numerical model is developed for a 4-bed adsorption cycle implemented with the master-and-slave configuration and the aforementioned internal heat recovery scheme. The present model captures the reversed adsorption/desorption phenomena frequently associated with the unmatched switching periods. Mesoporous silica gel and water vapor emanated from the evaporation of the seawater are employed as the adsorbent and adsorbate pair. The experimental data and investigation for such configurations are reported for the first time at heat source temperatures from 50 °C to 70 °C. The numerical model is validated rigorously and the parametric study is conducted for the performance of the cycle at assorted operation conditions such as hot and cooling water inlet temperatures and the cycle times. The specific daily water production (SDWP) of the present cycle is found to be about 10 m/day per tonne of silica gel for the heat source temperature at 70 °C. Performance comparison is conducted for various types of adsorption desalination cycles. It is observed that the AD cycle with the current configuration provides superior performance whilst is operational at unprecedentedly low heat source temperature as low as 50 °C.

  15. On the thermodynamics of waste heat recovery from internal combustion engine exhaust gas

    Science.gov (United States)

    Meisner, G. P.

    2013-03-01

    The ideal internal combustion (IC) engine (Otto Cycle) efficiency ηIC = 1-(1/r)(γ - 1) is only a function of engine compression ratio r =Vmax/Vmin and exhaust gas specific heat ratio γ = cP/cV. Typically r = 8, γ = 1.4, and ηIC = 56%. Unlike the Carnot Cycle where ηCarnot = 1-(TC/TH) for a heat engine operating between hot and cold heat reservoirs at TH and TC, respectively, ηIC is not a function of the exhaust gas temperature. Instead, the exhaust gas temperature depends only on the intake gas temperature (ambient), r, γ, cV, and the combustion energy. The ejected exhaust gas heat is thermally decoupled from the IC engine and conveyed via the exhaust system (manifold, pipe, muffler, etc.) to ambient, and the exhaust system is simply a heat engine that does no useful work. The maximum fraction of fuel energy that can be extracted from the exhaust gas stream as useful work is (1-ηIC) × ηCarnot = 32% for TH = 850 K (exhaust) and TC = 370 K (coolant). This waste heat can be recovered using a heat engine such as a thermoelectric generator (TEG) with ηTEG> 0 in the exhaust system. A combined IC engine and TEG system can generate net useful work from the exhaust gas waste heat with efficiency ηWH = (1-ηIC) × ηCarnot ×ηTEG , and this will increase the overall fuel efficiency of the total system. Recent improvements in TEGs yield ηTEG values approaching 15% giving a potential total waste heat conversion efficiency of ηWH = 4.6%, which translates into a fuel economy improvement approaching 5%. This work is supported by the US DOE under DE-EE0005432.

  16. PREFACE: 7th International Conference on Cooling & Heating Technologies (ICCHT 2014)

    Science.gov (United States)

    2015-09-01

    The Kyoto protocol has initiated a pledge from almost all developing and developed countries to be committed to reducing CO2 emissions. Development of new renewable energy technologies are also of interest in this conference. Greenhouse gases have contributed to global warming and other man-made disasters. Cooling and Heating communities also have responsibilities towards the commitment of reducing the greenhouse gas emissions. In addition, depleting natural resources also act as a threat to the Cooling and Heating industries, causing them to develop highly efficient equipment and innovative technologies. The 1st International Conference on Cooling & Heating Technologies was held in Hanoi Vietnam (Jan. 2005). Whereas the 2nd, 3rd, 4th and 5th ICCHT conferences were held in Dalian, China (Jul. 2006), Tokyo, Japan (Jul. 2007), Jinhae, Korea (Oct. 2008) and Bandung, Indonesia (Dec. 2010) respectively. The 6th International Conference on Cooling & Heating Technologies (ICCTH2012) was held in Xi'an in China on November 9-12, 2012. It is our pleasure to welcome you to the 7th International Conference on Cooling & Heating Technologies (ICCTH2014) on 4th - 6th November 2014 at the Grand Dorsett Subang Hotel, Subang Jaya, Selangor Darul Ehsan, Malaysia The Theme of the Conference is ''Sustainability and Innovation in Heating & Cooling Technologies''. The sub-themes are:- • CO2 Reduction and Low Carbon Technologies • HVAC System and Natural Ventilation • Energy & Alternative Energy • Computational Fluid Dynamics • Low Temperature & Refrigeration Engineering In conjunction with the Conference, an Exhibition will be organized as an integral part of the Conference. Project experiences, product solutions, new applications and state-of-the art information will be highlighted.

  17. Evaluation of induced activity, decay heat and dose rate distribution after shutdown in ITER

    Energy Technology Data Exchange (ETDEWEB)

    Maki, Koichi [Hitachi Ltd., Ibaraki (Japan). Hitachi Research Lab.; Satoh, Satoshi; Hayashi, Katsumi; Yamada, Koubun; Takatsu, Hideyuki; Iida, Hiromasa

    1997-03-01

    Induced activity, decay heat and dose rate distributions after shutdown were estimated for 1MWa/m{sup 2} operation in ITER. The activity in the inboard blanket one day after shutdown is 1.5x10{sup 11}Bq/cm{sup 3}, and the average decay heating rate 0.01w/cm{sup 3}. The dose rate outside the 120cm thick concrete biological shield is two order higher than the design criterion of 5{mu}Sv/h. This indicates that the biological shield thickness should be enhanced by 50cm in concrete, that is, total thickness 170cm for workers to enter the reactor room and to perform maintenance. (author)

  18. EPB standard EN ISO 52016: calculation of the building’s energy needs for heating and cooling, internal temperatures and heating and cooling load

    NARCIS (Netherlands)

    Dijk, H.A.L. van; Spiekman, M.E.; Hoes-van Oeffelen, E.C.M.

    2016-01-01

    EN ISO 52016-1 presents a coherent set of calculation methods at different levels of detail, for the (sensible) energy needs for the space heating and cooling and (latent) energy needs (de)humidification of a building and/or internal temperatures and heating and/or cooling loads, including the

  19. The International Heat Stress Genotype Experiment for modeling wheat response to heat: field experiments and AgMIP-Wheat multi-model simulations

    NARCIS (Netherlands)

    Martre, P.; Reynolds, M.P.; Asseng, S.; Ewert, F.; Alderman, P.D.; Cammarano, D.; Maiorano, Andrea; Ruane, A.C.; Aggarwal, P.K.; Anothai, J.; Supit, I.; Wolf, J.

    2017-01-01

    The data set contains a portion of the International Heat Stress Genotype Experiment (IHSGE) data used in the AgMIP-Wheat project to analyze the uncertainty of 30 wheat crop models and quantify the impact of heat on global wheat yield productivity. It includes two spring wheat cultivars grown during

  20. Book of short papers : International symposium on convective heat and mass transfer in sustainable energy Conv - 09. Volume 1

    International Nuclear Information System (INIS)

    2009-01-01

    This book contains the short papers from the International Symposium on Convective heat and Mass Transfer in sustainable Energy ( Conv-09), organized on behalf of the International Centre for Heat and Mass Transfer, it was held on April 26- 1st May, In Hammamet, Tunisia. The objective of this conference is to bring together researchers in a forum to exchange innovative ideas, methods and results, and visions of the future related to the general theme of convective heat and mass transfer

  1. Book of short papers : International symposium on convective heat and mass transfer in sustainable energy conv - 09. Volume 2

    International Nuclear Information System (INIS)

    2009-01-01

    This book contains the short papers from the International Symposium on convective heat and Mass Transfer in sustainable Energy ( conv-09), organized on behalf of the International Centre for Heat and Mass Transfer, it was held on April 26- 1st May, In Hammamet, Tunisia. The objective of this conference is to bring together researchers in a forum to exchange innovative ideas, methods and results, and visions of the future related to the general theme of convective heat and mass transfer

  2. Heat dissipation does not suppress an immune response in laboratory mice divergently selected for basal metabolic rate (BMR).

    Science.gov (United States)

    Książek, Aneta; Konarzewski, Marek

    2016-05-15

    The capacity for heat dissipation is considered to be one of the most important constraints on rates of energy expenditure in mammals. To date, the significance of this constraint has been tested exclusively under peak metabolic demands, such as during lactation. Here, we used a different set of metabolic stressors, which do not induce maximum energy expenditures and yet are likely to expose the potential constraining effect of heat dissipation. We compared the physiological responses of mice divergently selected for high (H-BMR) and low basal metabolic rate (L-BMR) to simultaneous exposure to the keyhole limpet haemocyanin (KLH) antigen and high ambient temperature (Ta). At 34°C (and at 23°C, used as a control), KLH challenge resulted in a transient increase in core body temperature (Tb) in mice of both line types (by approximately 0.4°C). Warm exposure did not produce line-type-dependent differences in Tb (which was consistently higher by ca. 0.6°C in H-BMR mice across both Ta values), nor did it result in the suppression of antibody synthesis. These findings were also supported by the lack of between-line-type differences in the mass of the thymus, spleen or lymph nodes. Warm exposure induced the downsizing of heat-generating internal organs (small intestine, liver and kidneys) and an increase in intrascapular brown adipose tissue mass. However, these changes were similar in scope in both line types. Mounting a humoral immune response in selected mice was therefore not affected by ambient temperature. Thus, a combined metabolic challenge of high Ta and an immune response did not appreciably compromise the capacity to dissipate heat, even in the H-BMR mice. © 2016. Published by The Company of Biologists Ltd.

  3. Artificial Neural Networks-Based Software for Measuring Heat Collection Rate and Heat Loss Coefficient of Water-in-Glass Evacuated Tube Solar Water Heaters.

    Science.gov (United States)

    Liu, Zhijian; Liu, Kejun; Li, Hao; Zhang, Xinyu; Jin, Guangya; Cheng, Kewei

    2015-01-01

    Measurements of heat collection rate and heat loss coefficient are crucial for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, conventional measurement requires expensive detection devices and undergoes a series of complicated procedures. To simplify the measurement and reduce the cost, software based on artificial neural networks for measuring heat collection rate and heat loss coefficient of water-in-glass evacuated tube solar water heaters was developed. Using multilayer feed-forward neural networks with back-propagation algorithm, we developed and tested our program on the basis of 915 measured samples of water-in-glass evacuated tube solar water heaters. This artificial neural networks-based software program automatically obtained accurate heat collection rate and heat loss coefficient using simply "portable test instruments" acquired parameters, including tube length, number of tubes, tube center distance, heat water mass in tank, collector area, angle between tubes and ground and final temperature. Our results show that this software (on both personal computer and Android platforms) is efficient and convenient to predict the heat collection rate and heat loss coefficient due to it slow root mean square errors in prediction. The software now can be downloaded from http://t.cn/RLPKF08.

  4. Effect of cooling rates on the weld heat affected zone coarse grain microstructure

    Directory of Open Access Journals (Sweden)

    Roman Celin

    2018-04-01

    Full Text Available The effect of a cooling rate on the S690Q quenched and tempered steel welded joint coarse grain heat affected zone microstructure was investigated using a dilatometer with controlled heating and cooling fixture. Steel samples were heated to a peak temperature of 1350 °C and cooled at the different cooling time Dt8/5. A dilatometric analysis and hardness measurements of the simulated thermal cycle coarse grain samples were done. Transformation start and finish temperature were determined using dilatation vs. temperature data analysis. The microstructure of the sample with a cooling time 5 s consists of martensite, whereas at cooling time 80 s a bainitic microstructure was observed. The investigated steel cooling cycle using simulation approach makes possible to determine the range of an optimum CG HAZ cooling time for the welding.

  5. The effect of wind on the rate of heat loss from avian cup-shaped nests.

    Science.gov (United States)

    Heenan, Caragh B; Seymour, Roger S

    2012-01-01

    Forced convection can significantly influence the heat loss from birds and their offspring but effects may be reduced by using sheltered micro-sites such as cavities or constructing nests. The structural and thermal properties of the nests of two species, the spiny-cheeked honeyeater (Acanthagenys rufogularis) and yellow-throated miner (Manorina flavigula), were measured in relation to three wind speeds. Nest dimensions differ between the two species, despite the similar body mass of the incubating adults, however nest conductance is comparable. As wind speed increases, so does the rate of heat loss from the nests of both species, and further still during incubation recesses. The significance of forced convection through the nest is a near-doubling in heat production required by the parent, even when incubating at relatively low wind speeds. This provides confirmation that selecting a sheltered nest site is important for avian reproductive success.

  6. The effect of wind on the rate of heat loss from avian cup-shaped nests.

    Directory of Open Access Journals (Sweden)

    Caragh B Heenan

    Full Text Available Forced convection can significantly influence the heat loss from birds and their offspring but effects may be reduced by using sheltered micro-sites such as cavities or constructing nests. The structural and thermal properties of the nests of two species, the spiny-cheeked honeyeater (Acanthagenys rufogularis and yellow-throated miner (Manorina flavigula, were measured in relation to three wind speeds. Nest dimensions differ between the two species, despite the similar body mass of the incubating adults, however nest conductance is comparable. As wind speed increases, so does the rate of heat loss from the nests of both species, and further still during incubation recesses. The significance of forced convection through the nest is a near-doubling in heat production required by the parent, even when incubating at relatively low wind speeds. This provides confirmation that selecting a sheltered nest site is important for avian reproductive success.

  7. International portfolio flows and exchange rate volatility for emerging markets

    OpenAIRE

    Caporale, Guglielmo Maria; Ali, Faek Menla; Spagnolo, Fabio; Spagnolo, Nicola

    2015-01-01

    This paper investigates the effects of equity and bond portfolio inflows on exchange rate volatility, using monthly bilateral data for the US vis-a-vis eight Asian developing and emerging countries (India, Indonesia, South Korea, Pakistan, Hong Kong, Thailand, the Philippines, and Taiwan) over the period 1993:01-2012:11, and estimating a time-varying transition probability Markov-switching model. We find that net equity (bond) inflows drive the exchange rate to a high (low) volatility state. ...

  8. The effect of sampling rate on interpretation of the temporal characteristics of radiative and convective heating in wildland flames

    Science.gov (United States)

    David Frankman; Brent W. Webb; Bret W. Butler; Daniel Jimenez; Michael Harrington

    2012-01-01

    Time-resolved radiative and convective heating measurements were collected on a prescribed burn in coniferous fuels at a sampling frequency of 500 Hz. Evaluation of the data in the time and frequency domain indicate that this sampling rate was sufficient to capture the temporal fluctuations of radiative and convective heating. The convective heating signal contained...

  9. Joule heat production rate and the particle energy injection rate as a function of the geomagnetic indices AE and AL

    International Nuclear Information System (INIS)

    Ahn, B.; Akasofu, S.; Kamide, Y.

    1983-01-01

    As a part of the joint efforts of operating six meridian chains of magnetometers during the IMS, magnetic records from 71 stations are used to deduce the distribution of electric fields and currents in the polar ionosphere for March 17, 18, and 19, 1978. As a continuation of this project, we have constructed hourly distribution maps of the Joule heat production rate and their sum over the entire polar region on the three days. For this purpose the conductivity distribution is inferred at each instant partially on the basis of an empirical method devised by Ahn et al. (1982). The particle energy injection rate is estimated similarly by using an empirical method. The data set thus obtained allows us to estimate also the global Joule heat production rate U/sub J/, the global particle energy injection rate U/sub A/ and the sum U/sub Gamma/ of the two quantities. It is found that three global quantities (watt) are related almost linearly to the AE(nT) and AL(nT) indices. Our present estimates give the following relationships: U/sub J/ = 2.3 times 10 8 x AE 8 U/sub A/ = 0.6 times 10 8 x AE 8 and U/sub I/ = 2.9 times 10 8 x AE: U/sub J/ = 3.0 times 10 8 x AL 8 U/sub A/ = 0.8 times 10 8 x AL, and U/sub I/ = 3.8 times 10 8 x AL

  10. ITER Generic Diagnostic Upper Port Plug Nuclear Heating and Personnel Dose Rate Assessment

    International Nuclear Information System (INIS)

    Feder, Russell E.; Youssef, Mahmoud Z.

    2009-01-01

    Neutronics analysis to find nuclear heating rates and personnel dose rates were conducted in support of the integration of diagnostics in to the ITER Upper Port Plugs. Simplified shielding models of the Visible-Infrared diagnostic and of a large aperture diagnostic were incorporated in to the ITER global CAD model. Results for these systems are representative of typical designs with maximum shielding and a small aperture (Vis-IR) and minimal shielding with a large aperture. The neutronics discrete-ordinates code ATTILA(reg s ign) and SEVERIAN(reg s ign) (the ATTILA parallel processing version) was used. Material properties and the 500 MW D-T volume source were taken from the ITER 'Brand Model' MCNP benchmark model. A biased quadrature set equivalent to Sn=32 and a scattering degree of Pn=3 were used along with a 46-neutron and 21-gamma FENDL energy subgrouping. Total nuclear heating (neutron plug gamma heating) in the upper port plugs ranged between 380 and 350 kW for the Vis-IR and Large Aperture cases. The Large Aperture model exhibited lower total heating but much higher peak volumetric heating on the upper port plug structure. Personnel dose rates are calculated in a three step process involving a neutron-only transport calculation, the generation of activation volume sources at pre-defined time steps and finally gamma transport analyses are run for selected time steps. ANSI-ANS 6.1.1 1977 Flux-to-Dose conversion factors were used. Dose rates were evaluated for 1 full year of 500 MW DT operation which is comprised of 3000 1800-second pulses. After one year the machine is shut down for maintenance and personnel are permitted to access the diagnostic interspace after 2-weeks if dose rates are below 100 (micro)Sv/hr. Dose rates in the Visible-IR diagnostic model after one day of shutdown were 130 (micro)Sv/hr but fell below the limit to 90 (micro)Sv/hr 2-weeks later. The Large Aperture style shielding model exhibited higher and more persistent dose rates. After 1

  11. Local linear heat rate ramps in the WWER-440 transient regimes

    International Nuclear Information System (INIS)

    Brik, A.N.; Bibilashvili, Ju.L.; Bogatyr, S.M.; Medvedev, A.V.

    1998-01-01

    The operation of the WWER-440 reactors must be accomplished in such a way that the fuel rods durability would be high enough during the whole operation period. The important factors determining the absence of fuel rod failures are the criteria limiting the core characteristics (fuel rod and fuel assembly power, local linear heat rate, etc.). For the transient and load follow conditions the limitations on the permissible local linear rate ramp are also introduced. This limitation is the result of design limit of stress corrosion cracking of the fuel cladding and depends on the local fuel burn-up. The control rod motion is accompanied by power redistribution, which, in principle, can result in violating the design and operation limitations. Consequently, this motion have to be such as the core parameters, including the local ramps of the linear heat generation rates would not exceed the permissible ones.The paper considers the problem of WWER-440 reactor control under transient and load follow conditions and the associated optimisation of local linear heat generation rate ramps. The main factors affecting the solution of the problem under consideration are discussed. Some recommendations for a more optimal reactor operation are given.(Author)

  12. Additive effects of heating and exercise on baroreflex control of heart rate in healthy males.

    Science.gov (United States)

    Peçanha, Tiago; Forjaz, Cláudia L M; Low, David A

    2017-12-01

    This study assessed the additive effects of passive heating and exercise on cardiac baroreflex sensitivity (cBRS) and heart rate variability (HRV). Twelve healthy young men (25 ± 1 yr, 23.8 ± 0.5 kg/m 2 ) randomly underwent two experimental sessions: heat stress (HS; whole body heat stress using a tube-lined suit to increase core temperature by ~1°C) and normothermia (NT). Each session was composed of a preintervention rest (REST1); HS or NT interventions; postintervention rest (REST2); and 14 min of cycling exercise [7 min at 40%HR reserve (EX1) and 7 min at 60%HR reserve (EX2)]. Heart rate and finger blood pressure were continuously recorded. cBRS was assessed using the sequence (cBRS SEQ ) and transfer function (cBRS TF ) methods. HRV was assessed using the indexes standard deviation of RR intervals (SDNN) and root mean square of successive RR intervals (RMSSD). cBRS and HRV were not different between sessions during EX1 and EX2 (i.e., matched heart rate conditions: EX1 = 116 ± 3 vs. 114 ± 3 and EX2 = 143 ± 4 vs. 142 ± 3 beats/min but different workloads: EX1 = 50 ± 9 vs. 114 ± 8 and EX2 = 106 ± 10 vs. 165 ± 8 W; for HS and NT, respectively; P heat stress to exercise does not affect cBRS and HRV. Alternatively, in workload-matched conditions, the addition of heat to exercise results in reduced cBRS and HRV compared with exercise in normothermia. NEW & NOTEWORTHY The present study assessed cardiac baroreflex sensitivity during the combination of heat and exercise stresses. This is the first study to show that prior whole body passive heating reduces cardiac baroreflex sensitivity and autonomic modulation of heart rate during exercise. These findings contribute to the better understanding of the role of thermoregulation on cardiovascular regulation during exercise.

  13. Genetic component of sensitivity to heat stress for nonreturn rate of Brazilian Holstein cattle.

    Science.gov (United States)

    Santana, M L; Bignardi, A B; Stefani, G; El Faro, L

    2017-08-01

    The objectives of the present study were: 1) to investigate variation in the genetic component of heat stress for nonreturn rate at 56 days after first artificial insemination (NR56); 2) to identify and characterize the genotype by environment interaction (G × E) due to heat stress for NR56 of Brazilian Holstein cattle. A linear random regression model (reaction norm model) was applied to 51,748 NR56 records of 28,595 heifers and multiparous cows. The decline in NR56 due to heat stress was more pronounced in milking cows compared to heifers. The age of females at first artificial insemination and temperature-humidity index (THI) exerted an important influence on the genetic parameters of NR56. Several evidence of G × E on NR56 were found as the high slope/intercept ratio and frequent intersection of reaction norms. Additionally, the genetic correlation between NR56 at opposite extremes of the THI scale reached estimates below zero, indicating that few of the same genes are responsible for NR56 under conditions of thermoneutrality and heat stress. The genetic evaluation and selection for NR56 in Holstein cattle reared under (sub)tropical conditions should therefore take into consideration the genetic variation on age at insemination and G × E due to heat stress. Copyright © 2017 Elsevier Inc. All rights reserved.

  14. The effect of internal ribbing on forced convective heat transfer in circular-sectioned tubes

    International Nuclear Information System (INIS)

    Farhadi Rahmat-Abadi, K.; Morris, W. D.

    2003-01-01

    This paper presents the results of an experimental examination of the effect of internal circumferential ribs on forced convection in circular-sectioned tubes. The work is relevant to the internal cooling of gas turbine rotor blades. The influence of rib geometry is investigated for three different rib configurations and simple design-type, empirical equations are developed for estimating heat transfer at rib and mid-rib locations. It is demonstrated that heat transfer may be improved by up to three fold in relation to fully developed forced convection in smooth-walled tubes. The geometric parameters which have been used for the experiments are typical of those currently applied to gas turbine blade cooling designs

  15. Heat up and potential failure of BWR upper internals during a severe accident

    Energy Technology Data Exchange (ETDEWEB)

    Robb, Kevin R [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2015-01-01

    In boiling water reactors, the steam dome, steam separators, and dryers above the core are comprised of approximately 100 tons of stainless steel. During a severe accident in which the coolant boils away and exothermic oxidation of zirconium occurs, gases (steam and hydrogen) are superheated in the core region and pass through the upper internals. Historically, the upper internals have been modeled using severe accident codes with relatively simple approximations. The upper internals are typically modeled in MELCOR as two lumped volumes with simplified heat transfer characteristics, with no structural integrity considerations, and with limited ability to oxidize, melt, and relocate. The potential for and the subsequent impact of the upper internals to heat up, oxidize, fail, and relocate during a severe accident was investigated. A higher fidelity representation of the shroud dome, steam separators, and steam driers was developed in MELCOR v1.8.6 by extending the core region upwards. This modeling effort entailed adding 45 additional core cells and control volumes, 98 flow paths, and numerous control functions. The model accounts for the mechanical loading and structural integrity, oxidation, melting, flow area blockage, and relocation of the various components. The results indicate that the upper internals can reach high temperatures during a severe accident; they are predicted to reach a high enough temperature such that they lose their structural integrity and relocate. The additional 100 tons of stainless steel debris influences the subsequent in-vessel and ex-vessel accident progression.

  16. Artificial Neural Networks-Based Software for Measuring Heat Collection Rate and Heat Loss Coefficient of Water-in-Glass Evacuated Tube Solar Water Heaters

    Science.gov (United States)

    Liu, Zhijian; Liu, Kejun; Li, Hao; Zhang, Xinyu; Jin, Guangya; Cheng, Kewei

    2015-01-01

    Measurements of heat collection rate and heat loss coefficient are crucial for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, conventional measurement requires expensive detection devices and undergoes a series of complicated procedures. To simplify the measurement and reduce the cost, software based on artificial neural networks for measuring heat collection rate and heat loss coefficient of water-in-glass evacuated tube solar water heaters was developed. Using multilayer feed-forward neural networks with back-propagation algorithm, we developed and tested our program on the basis of 915measuredsamples of water-in-glass evacuated tube solar water heaters. This artificial neural networks-based software program automatically obtained accurate heat collection rateand heat loss coefficient using simply "portable test instruments" acquired parameters, including tube length, number of tubes, tube center distance, heat water mass in tank, collector area, angle between tubes and ground and final temperature. Our results show that this software (on both personal computer and Android platforms) is efficient and convenient to predict the heat collection rate and heat loss coefficient due to it slow root mean square errors in prediction. The software now can be downloaded from http://t.cn/RLPKF08. PMID:26624613

  17. Numerical and experimental investigation of melting with internal heat generation within cylindrical enclosures

    Energy Technology Data Exchange (ETDEWEB)

    Amber Shrivastava; Brian Williams; Ali S. Siahpush; Bruce Savage; John Crepeau

    2014-06-01

    There have been significant efforts by the heat transfer community to investigate the melting phenomenon of materials. These efforts have included the analytical development of equations to represent melting, numerical development of computer codes to assist in modeling the phenomena, and collection of experimental data. The understanding of the melting phenomenon has application in several areas of interest, for example, the melting of a Phase Change Material (PCM) used as a thermal storage medium as well as the melting of the fuel bundle in a nuclear power plant during an accident scenario. The objective of this research is two-fold. First a numerical investigation, using computational fluid dynamics (CFD), of melting with internal heat generation for a vertical cylindrical geometry is presented. Second, to the best of authors knowledge, there are very limited number of engineering experimental results available for the case of melting with Internal Heat Generation (IHG). An experiment was performed to produce such data using resistive, or Joule, heating as the IHG mechanism. The numerical results are compared against the experimental results and showed favorable correlation. Uncertainties in the numerical and experimental analysis are discussed. Based on the numerical and experimental analysis, recommendations are made for future work.

  18. Design, calibration and error analysis of instrumentation for heat transfer measurements in internal combustion engines

    Science.gov (United States)

    Ferguson, C. R.; Tree, D. R.; Dewitt, D. P.; Wahiduzzaman, S. A. H.

    1987-01-01

    The paper reports the methodology and uncertainty analyses of instrumentation for heat transfer measurements in internal combustion engines. Results are presented for determining the local wall heat flux in an internal combustion engine (using a surface thermocouple-type heat flux gage) and the apparent flame-temperature and soot volume fraction path length product in a diesel engine (using two-color pyrometry). It is shown that a surface thermocouple heat transfer gage suitably constructed and calibrated will have an accuracy of 5 to 10 percent. It is also shown that, when applying two-color pyrometry to measure the apparent flame temperature and soot volume fraction-path length, it is important to choose at least one of the two wavelengths to lie in the range of 1.3 to 2.3 micrometers. Carefully calibrated two-color pyrometer can ensure that random errors in the apparent flame temperature and in the soot volume fraction path length will remain small (within about 1 percent and 10-percent, respectively).

  19. Heat transfer analysis in internally-cooled fuel elements by means of a conformal mapping approach

    International Nuclear Information System (INIS)

    Sarmiento, G.S.; Laura, P.A.A.

    1981-01-01

    The present paper deals with an approximate solution of the steady-state heat conduction problem in internally cooled fuel elements of fast breeder reactors. Explicit expressions for the dimensionless temperature distribution in terms of the governing physical and geometrical parameters are determined by means of a coupled conformal mapping-variational approach. The results obtained are found to be in very good agreement with those calculated by means of a finite element code. (orig.)

  20. Conflict between internal combustion engine and thermoelectric generator during waste heat recovery in cars

    Science.gov (United States)

    Korzhuev, M. A.

    2011-02-01

    It is shown that an internal combustion engine and a thermoelectric generator (TEG) arranged on the exhaust pipe of this engine come into the conflict of thermal machines that is related to using the same energy resource. The conflict grows with increasing useful electric power W e of the TEG, which leads to the limitation of both the maximum TEG output power ( W {e/max}) and the possibility of waste heat recovery in cars.

  1. Energy study of heat pumps and energy storage at Cisco Systems International; Energiestudie warmtepompen en energieopslag Cisco Systems International

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2000-05-23

    Cisco Systems International considers the use of energy storage in combination with heat pumps for the new office building in Amsterdam South-East, Netherlands. This office building has a floor space of 35,000 m{sup 2}. In a later phase this can be enlarged to 45,000 m{sup 2} (phase 1b) or 90,000 m{sup 2} (phase 2). This study is based on phase 1b. The mounting heat capacity is 2,760 kW and the cooling capacity is 7,045 kW. The annually cooling demand is estimated to be 30,400 MWh/a. The computer cooling forms a greater part of the cooling request (28,300 MWh/a). This study is a pilot study to the applicability of subsurface energy storage where heat pumps in the new office building are involved. However, nearby the Cisco location IKEA (furniture warehouse) has also planned an energy storage system. Therefore, the interaction between the two storage systems was examined. Cost effectiveness was analysed by comparison of the storage system with an energy system using conventional cooling machines and gas boilers. 5 refs.

  2. Sustainability rating as internal challenge for the financial sector

    NARCIS (Netherlands)

    Zoeteman, Bastiaan; Kopp, H.E.

    2016-01-01

    Sustainability rating is rapidly maturing to a level where even the complex concept of sustainable development—including the ecological, sociocultural, and economic pillars and their components, as well as governance aspects such as attitudes—can be objectively described and quantitatively analyzed.

  3. Human Capital and the Internal Rate of Return.

    Science.gov (United States)

    Rosen, Sherwin

    The theory of human capital has made a significant impact on the practice of modern labor economics. At a broad and general level, the concept of human capital has obvious appeal for its simplicity, analytical power, and relationship to economic theory. The fundamental problem in labor economics is the determination of wage rates and earnings;…

  4. Labour Force Participation Rates of Older Persons: An International Comparison.

    Science.gov (United States)

    Clark, Robert L.; Anker, Richard

    1990-01-01

    Using data from 151 countries, labor force participation of older men and women was analyzed and related to economic, demographic, and policy variables. Reduced participation rates are related to increased income levels, structural changes, social security programs, and, for men, the ratio of older persons to persons of standard working age. (SK)

  5. CHF during flow rate, pressure and power transients in heated channels

    International Nuclear Information System (INIS)

    Celata, G.P.; Cumo, M.

    1987-01-01

    The behaviour of forced two-phase flows following inlet flow rate, pressure and power transients is presented here with reference to experiments performed with a R-12 loop. A circular duct, vertical test section (L = 2300 mm; D = 7.5 mm) instrumented with fluid (six) and wall (twelve) thermocouples has been employed. Transients have been carried out performing several values of flow decays (exponential decrease), depressurization rates (exponential decrease) and power inputs (step-wise increase). Experimental data have shown the complete inadequacy of steady-state critical heat flux correlations in predicting the onset of boiling crisis during fast transients. Data analysis for a better theoretical prediction of CHF occurrence during transient conditions has been accomplished, and design correlations for critical heat flux and time-to-crisis predictions have been proposed for the different types of transients

  6. Fissure formation in coke. 2: Effect of heating rate, shrinkage and coke strength

    Energy Technology Data Exchange (ETDEWEB)

    D.R. Jenkins; M.R. Mahoney [CSIRO, North Ryde, NSW (Australia). Mathematical and Information Sciences

    2010-07-15

    We investigate the effects of the heating rate, coke shrinkage and coke breakage strength upon the fissure pattern developed in a coke oven charge during carbonisation. This is done principally using a mechanistic model of the formation of fissures, which considers them to be an array of equally spaced fissures, whose depth follows a 'period doubling' pattern based upon the time history of the fissures. The model results are compared with pilot scale coke oven experiments. The results show that the effect of heating rate on the fissure pattern is different to the effect of coke shrinkage, while the effect of coke breakage strength on the pattern is less pronounced. The results can be seen in both the shape and size of resulting coke lumps after stabilisation. The approach gives the opportunity to consider means of controlling the carbonisation process in order to tune the size of the coke lumps produced. 7 refs., 18 figs., 4 tabs.

  7. Reducing uranium and thorium level in Zircon: effect of heat treatment on rate of leaching

    International Nuclear Information System (INIS)

    Meor Yusoff Meor Sulaiman

    2002-01-01

    Considerable amount of uranium and thorium are found in Malaysian zircon and the level is much higher than the minimum value adopted by many importing countries. Selective leaching had been applied as an important technique to reduce these elements. An initial study was carried out using hydrochloric acid leaching system but the result was not favourable. The rate of uranium and thorium leached can be further improved by introducing a heat pretreatment process prior to leaching (Author)

  8. Effect of heating rate and grain size on the melting behavior of the alloy Nb-47 mass % Ti in pulse-heating experiments

    International Nuclear Information System (INIS)

    Basak, D.; Boettinger, W.J.; Josell, D.; Coriell, S.R.; McClure, J.L.; Cezairliyan, A.

    1999-01-01

    The effect of heating rate and grain size on the melting behavior of Nb-47 mass% Ti is measured and modeled. The experimental method uses rapid resistive self-heating of wire specimens at rates between ∼10 2 and ∼10 4 K/s and simultaneous measurement of radiance temperature and normal spectral emissivity as functions of time until specimen collapse, typically between 0.4 and 0.9 fraction melted. During heating, a sharp drop in emissivity is observed at a temperature that is independent of heating rate and grain size. This drop is due to surface and grain boundary melting at the alloy solidus temperature even though there is very little deflection (limited melting) of the temperature-time curve from the imposed heating rate. Above the solidus temperature, the emissivity remains nearly constant with increasing temperature and the temperature vs time curve gradually reaches a sloped plateau over which the major fraction of the specimen melts. As the heating rate and/or grain size is increased, the onset temperature of the sloped plateau approaches the alloy liquidus temperature and the slope of the plateau approaches zero. This interpretation of the shapes of the temperature-time-curves is supported by a model that includes diffusion in the solid coupled with a heat balance during the melting process. There is no evidence of loss of local equilibrium at the melt front during melting in these experiments

  9. First results of out-of-pile experiments concerning cooling phenomena of molten layers with internal heat sources

    International Nuclear Information System (INIS)

    Fieg, G.

    1977-01-01

    After severe hypothetical reactor accidents, large amounts of molten core material with internal heat generation may appear. It must be guaranteed that these materials can be kept within the containment. To clarify this situation, the knowledge of heat transport from liquid layers with internal heat generation is needed. First experimental results on heat transport from internally heated horizontal fluid layers are presented. The experiments have been performed in a smooth horizontal vessel with the base of 15 x 15 cm 2 . The Joule-heated liquid layer (depth L = 1 cm - 3.5 cm) is enclosed between two isothermal horizontal walls. They are polished fore parts of heat exchangers. The temperatures of the walls were held constant with thermostatically controlled water circulating through the heat exchangers. Horizontal heat fluxes were depressed by appropriate insulation of the side walls. The total heat transport to the upper and lower boundaries has been measured by the mass transport through the heat exchangers and the temperature rise of the cooling water

  10. Effect of heating and cooling rate on the kinetics of allotropic phase changes in uranium: A differential scanning calorimetry study

    International Nuclear Information System (INIS)

    Rai, Arun Kumar; Raju, S.; Jeyaganesh, B.; Mohandas, E.; Sudha, R.; Ganesan, V.

    2009-01-01

    The kinetic aspects of allotropic phase changes in uranium are studied as a function of heating/cooling rate in the range 10 0 -10 2 K min -1 by isochronal differential scanning calorimetry. The transformation arrest temperatures revealed a remarkable degree of sensitivity to variations of heating and cooling rate, and this is especially more so for the transformation finish (T f ) temperatures. The results obtained for the α → β and β → γ transformations during heating confirm to the standard Kolmogorov-Johnson-Mehl-Avrami (KJMA) model for a nucleation and growth mediated process. The apparent activation energy Q eff for the overall transformation showed a mild increase with increasing heating rate. In fact, the heating rate normalised Arrhenius rate constant, k/β reveals a smooth power law decay with increasing heating rate (β). For the α → β phase change, the observed DSC peak profile for slower heating rates contained a distinct shoulder like feature, which however is absent in the corresponding profiles found for higher heating rates. The kinetics of γ → β phase change on the other hand, is best described by the two-parameter Koistinen-Marburger empirical relation for the martensitic transformation

  11. Conception rate of artificially inseminated Holstein cows affected by cloudy vaginal mucus, under intense heat conditions

    Directory of Open Access Journals (Sweden)

    Miguel Mellado

    2015-06-01

    Full Text Available The objective of this work was to obtain prevalence estimates of cloudy vaginal mucus in artificially inseminated Holstein cows raised under intense heat, in order to assess the effect of meteorological conditions on its occurrence during estrus and to determine its effect on conception rate. In a first study, an association was established between the occurrence of cloudy vaginal mucus during estrus and the conception rate of inseminated cows (18,620 services, raised under intense heat (mean annual temperature of 22°C, at highly technified farms, in the arid region of northern Mexico. In a second study, data from these large dairy operations were used to assess the effect of meteorological conditions throughout the year on the occurrence of cloudy vaginal mucus during artificial insemination (76,899 estruses. The overall rate of estruses with cloudy vaginal mucus was 21.4% (16,470/76,899; 95% confidence interval = 21.1-21.7%. The conception rate of cows with clean vaginal mucus was higher than that of cows with abnormal mucus (30.6 vs. 22%. Prevalence of estruses with cloudy vaginal mucus was strongly dependent on high ambient temperature and markedly higher in May and June. Acceptable conception rates in high milk-yielding Holstein cows can only be obtained with cows showing clear and translucid mucus at artificial insemination.

  12. 76 FR 6128 - Energy Exchange International, LLC; Supplemental Notice That Initial Market-Based Rate Filing...

    Science.gov (United States)

    2011-02-03

    ... DEPARTMENT OF ENERGY Federal Energy Regulatory Commission [Docket No. ER11-2730-000] Energy Exchange International, LLC; Supplemental Notice That Initial Market-Based Rate Filing Includes Request for... proceeding Energy Exchange International, LLC's application for market-based rate authority, with an...

  13. Statistical properties of Joule heating rate, electric field and conductances at high latitudes

    Directory of Open Access Journals (Sweden)

    A. T. Aikio

    2009-07-01

    Full Text Available Statistical properties of Joule heating rate, electric field and conductances in the high latitude ionosphere are studied by a unique one-month measurement made by the EISCAT incoherent scatter radar in Tromsø (66.6 cgmlat from 6 March to 6 April 2006. The data are from the same season (close to vernal equinox and from similar sunspot conditions (about 1.5 years before the sunspot minimum providing an excellent set of data to study the MLT and Kp dependence of parameters with high temporal and spatial resolution.

    All the parameters show a clear MLT variation, which is different for low and high Kp conditions. Our results indicate that the response of morning sector conductances and conductance ratios to increased magnetic activity is stronger than that of the evening sector. The co-location of Pedersen conductance maximum and electric field maximum in the morning sector produces the largest Joule heating rates 03–05 MLT for Kp≥3. In the evening sector, a smaller maximum occurs at 18 MLT. Minimum Joule heating rates in the nightside are statistically observed at 23 MLT, which is the location of the electric Harang discontinuity.

    An important outcome of the paper are the fitted functions for the Joule heating rate as a function of electric field magnitude, separately for four MLT sectors and two activity levels (Kp<3 and Kp≥3. In addition to the squared electric field, the fit includes a linear term to study the possible anticorrelation or correlation between electric field and conductance. In the midday sector, positive correlation is found as well as in the morning sector for the high activity case. In the midnight and evening sectors, anticorrelation between electric field and conductance is obtained, i.e. high electric fields are associated with low conductances. This is expected to occur in the return current regions adjacent to

  14. Statistical properties of Joule heating rate, electric field and conductances at high latitudes

    Directory of Open Access Journals (Sweden)

    A. T. Aikio

    2009-07-01

    Full Text Available Statistical properties of Joule heating rate, electric field and conductances in the high latitude ionosphere are studied by a unique one-month measurement made by the EISCAT incoherent scatter radar in Tromsø (66.6 cgmlat from 6 March to 6 April 2006. The data are from the same season (close to vernal equinox and from similar sunspot conditions (about 1.5 years before the sunspot minimum providing an excellent set of data to study the MLT and Kp dependence of parameters with high temporal and spatial resolution. All the parameters show a clear MLT variation, which is different for low and high Kp conditions. Our results indicate that the response of morning sector conductances and conductance ratios to increased magnetic activity is stronger than that of the evening sector. The co-location of Pedersen conductance maximum and electric field maximum in the morning sector produces the largest Joule heating rates 03–05 MLT for Kp≥3. In the evening sector, a smaller maximum occurs at 18 MLT. Minimum Joule heating rates in the nightside are statistically observed at 23 MLT, which is the location of the electric Harang discontinuity. An important outcome of the paper are the fitted functions for the Joule heating rate as a function of electric field magnitude, separately for four MLT sectors and two activity levels (Kp<3 and Kp≥3. In addition to the squared electric field, the fit includes a linear term to study the possible anticorrelation or correlation between electric field and conductance. In the midday sector, positive correlation is found as well as in the morning sector for the high activity case. In the midnight and evening sectors, anticorrelation between electric field and conductance is obtained, i.e. high electric fields are associated with low conductances. This is expected to occur in the return current regions adjacent to auroral arcs as a result of ionosphere-magnetosphere coupling, as discussed by Aikio et al. (2004 In

  15. Transformation of deformation martensite into austenite in stainless steels at various heating rates

    International Nuclear Information System (INIS)

    Gojkhenberg, Yu.N.; Shtejnberg, M.M.

    1978-01-01

    Under isothermal conditions and with continuous preheating at defferent rates, the inverse transformation of deformation martensite that is obtained through reductions to small, medium and great degrees, has been studied. It has been established that depending on the preheat rate, the temperature of the end α → ν of rebuilding varies according to a curve having a maximum. The ascending branch of that curve is connected with the diffusion-controlled shear transformation, whereas the descending branch with the transition to the martensite reaction of austenite formation. As the deformation degree increases, the temperature of the end of the inverse transformation decreases. As a result, recrystallization of austenite proceeds only after completing α → ν transition, when heating the steels deformed to the medium degree at rates of at least 25 deg/sec and after high reductions at rates of at least 0.8 deg/sec

  16. Skin blood flow and local temperature independently modify sweat rate during passive heat stress in humans.

    Science.gov (United States)

    Wingo, Jonathan E; Low, David A; Keller, David M; Brothers, R Matthew; Shibasaki, Manabu; Crandall, Craig G

    2010-11-01

    Sweat rate (SR) is reduced in locally cooled skin, which may result from decreased temperature and/or parallel reductions in skin blood flow. The purpose of this study was to test the hypotheses that decreased skin blood flow and decreased local temperature each independently attenuate sweating. In protocols I and II, eight subjects rested supine while wearing a water-perfused suit for the control of whole body skin and internal temperatures. While 34°C water perfused the suit, four microdialysis membranes were placed in posterior forearm skin not covered by the suit to manipulate skin blood flow using vasoactive agents. Each site was instrumented for control of local temperature and measurement of local SR (capacitance hygrometry) and skin blood flow (laser-Doppler flowmetry). In protocol I, two sites received norepinephrine to reduce skin blood flow, while two sites received Ringer solution (control). All sites were maintained at 34°C. In protocol II, all sites received 28 mM sodium nitroprusside to equalize skin blood flow between sites before local cooling to 20°C (2 sites) or maintenance at 34°C (2 sites). In both protocols, individuals were then passively heated to increase core temperature ~1°C. Both decreased skin blood flow and decreased local temperature attenuated the slope of the SR to mean body temperature relationship (2.0 ± 1.2 vs. 1.0 ± 0.7 mg·cm(-2)·min(-1)·°C(-1) for the effect of decreased skin blood flow, P = 0.01; 1.2 ± 0.9 vs. 0.07 ± 0.05 mg·cm(-2)·min(-1)·°C(-1) for the effect of decreased local temperature, P = 0.02). Furthermore, local cooling delayed the onset of sweating (mean body temperature of 37.5 ± 0.4 vs. 37.6 ± 0.4°C, P = 0.03). These data demonstrate that local cooling attenuates sweating by independent effects of decreased skin blood flow and decreased local skin temperature.

  17. An Efficient Approximation of the Coronal Heating Rate for use in Global Sun-Heliosphere Simulations

    Science.gov (United States)

    Cranmer, Steven R.

    2010-02-01

    The origins of the hot solar corona and the supersonically expanding solar wind are still the subject of debate. A key obstacle in the way of producing realistic simulations of the Sun-heliosphere system is the lack of a physically motivated way of specifying the coronal heating rate. Recent one-dimensional models have been found to reproduce many observed features of the solar wind by assuming the energy comes from Alfvén waves that are partially reflected, then dissipated by magnetohydrodynamic turbulence. However, the nonlocal physics of wave reflection has made it difficult to apply these processes to more sophisticated (three-dimensional) models. This paper presents a set of robust approximations to the solutions of the linear Alfvén wave reflection equations. A key ingredient of the turbulent heating rate is the ratio of inward-to-outward wave power, and the approximations developed here allow this to be written explicitly in terms of local plasma properties at any given location. The coronal heating also depends on the frequency spectrum of Alfvén waves in the open-field corona, which has not yet been measured directly. A model-based assumption is used here for the spectrum, but the results of future measurements can be incorporated easily. The resulting expression for the coronal heating rate is self-contained, computationally efficient, and applicable directly to global models of the corona and heliosphere. This paper tests and validates the approximations by comparing the results to exact solutions of the wave transport equations in several cases relevant to the fast and slow solar wind.

  18. Influence of inlet velocity of air and solid particle feed rate on holdup mass and heat transfer characteristics in cyclone heat exchanger

    International Nuclear Information System (INIS)

    Mothilal, T.; Pitchandi, K.

    2015-01-01

    Present work elaborates the effect of inlet velocity of air and solid particle feed rate on holdup mass and heat transfer characteristics in a cyclone heat exchanger. The RNG k-ε turbulence model was adopted for modeling high turbulence flow and Discrete phase model (DPM) to track solid particles in a cyclone heat exchanger by ANSYS FLUENT software. The effect of inlet air velocity (5 to 25 m/s) and inlet solid particle feed rate of (0.2 to 2.5 g/s) at different particle diameter (300 to 500 μm) on holdup mass and heat transfer rate in cyclone heat exchanger was studied at air inlet temperature of 473 K. Results show that holdup mass and heat transfer rate increase with increase in inlet air velocity and inlet solid particle feed rate. Influence of solid particle feed rate on holdup mass has more significance. Experimental setup was built for high efficiency cyclone. Good agreement was found between experimental and simulation pressure drop. Empirical correlation was derived for dimensionless holdup mass and Nusselt number based on CFD data by regression technique. Correlation predicts dimensional holdup mass with +5% to -8% errors of experimental data and Nusselt number with +9% to -3%

  19. Influence of inlet velocity of air and solid particle feed rate on holdup mass and heat transfer characteristics in cyclone heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Mothilal, T. [T. J. S. Engineering College, Gummidipoond (India); Pitchandi, K. [Sri Venkateswara College of Engineering, Sriperumbudur (India)

    2015-10-15

    Present work elaborates the effect of inlet velocity of air and solid particle feed rate on holdup mass and heat transfer characteristics in a cyclone heat exchanger. The RNG k-ε turbulence model was adopted for modeling high turbulence flow and Discrete phase model (DPM) to track solid particles in a cyclone heat exchanger by ANSYS FLUENT software. The effect of inlet air velocity (5 to 25 m/s) and inlet solid particle feed rate of (0.2 to 2.5 g/s) at different particle diameter (300 to 500 μm) on holdup mass and heat transfer rate in cyclone heat exchanger was studied at air inlet temperature of 473 K. Results show that holdup mass and heat transfer rate increase with increase in inlet air velocity and inlet solid particle feed rate. Influence of solid particle feed rate on holdup mass has more significance. Experimental setup was built for high efficiency cyclone. Good agreement was found between experimental and simulation pressure drop. Empirical correlation was derived for dimensionless holdup mass and Nusselt number based on CFD data by regression technique. Correlation predicts dimensional holdup mass with +5% to -8% errors of experimental data and Nusselt number with +9% to -3%.

  20. Evaluation of the Internal and Borehole Resistances during Thermal Response Tests and Impact on Ground Heat Exchanger Design

    Directory of Open Access Journals (Sweden)

    Louis Lamarche

    2017-12-01

    Full Text Available The main parameters evaluated with a conventional thermal response test (TRT are the subsurface thermal conductivity surrounding the borehole and the effective borehole thermal resistance, when averaging the inlet and outlet temperature of a ground heat exchanger with the arithmetic mean. This effective resistance depends on two resistances: the 2D borehole resistance (Rb and the 2D internal resistance (Ra which is associated to the short-circuit effect between pipes in the borehole. This paper presents a field method to evaluate these two components separately. Two approaches are proposed. In the first case, the temperature at the bottom of the borehole is measured at the same time as the inlet and outlet temperatures as done in a conventional TRT. In the second case, different flow rates are used during the experiment to infer the internal resistance. Both approaches assumed a predefined temperature profile inside the borehole. The methods were applied to real experimental tests and compared with numerical simulations. Interesting results were found by comparison with theoretical resistances calculated with the multipole method. The motivation for this work is evidenced by analyzing the impact of the internal resistance on a typical geothermal system design. It is shown to be important to know both resistance components to predict the variation of the effective resistance when the flow rate and the height of the boreholes are changed during the design process.

  1. Background internal dose rates of earthworm and arthropod species in the forests of Aomori, Japan

    International Nuclear Information System (INIS)

    Yoshihito Ohtsuka; Yuichi Takaku; Shun'ichi Hisamatsu

    2015-01-01

    In this study, we measured the concentrations of several natural radionuclides in samples of one earthworm species and 11 arthropod species collected from four coniferous forests in Rokkasho, Aomori Prefecture, Japan, and we assessed the background internal radiation dose rate for each species. Dose rates were calculated by using the radionuclide concentrations in the samples and dose conversion coefficients obtained from the literature. The mean internal dose rate in the earthworm species was 0.28 μGy h -1 , and the mean internal dose rates in the arthropod species ranged between 0.036 and 0.69 μGy h -1 . (author)

  2. Transient natural convection in an internally heated fluid layer. Topical report, June 1975--June 1976

    International Nuclear Information System (INIS)

    Kulacki, F.A.; Emara, A.A.

    1976-06-01

    An experimental study of the transient response of a horizontal fluid layer subjected to a step change in internal energy generation has been conducted to determine the time scales for the development and decay of natural convection driven solely by the internal heat release. The layer is bounded from above by a rigid, constant temperature surface and from below by a rigid, insulated surface. Two types of unsteady convection processes are considered. In the first, the layer is brought to a motionless, isothermal state, and internal energy generation is suddenly started. In the second, steady natural convection is the initial state, and internal energy generation is suddenly stopped. For both cases, the time required for the development of the final steady state is determined by measuring the temperature response of the fluid with a small thermocouple probe. The time required for the development of the maximum temperature difference in the layer with internal generation and the time required for the complete decay of the maximum temperature difference of steady convection at a given Rayleigh number when internal energy generation is suddenly stopped are correlated with the Rayleigh number in equations which will find general application in PAHR problems in nuclear power reactors and particularly in the analysis of the small-time thermal response of in-vessel and ex-vessel molten core retention devices

  3. High temperature, high heating rate carbonisation - a route to new forms of carbon

    International Nuclear Information System (INIS)

    Wilson, M. A.

    1998-01-01

    Carbonisation (more properly called pyrolysis) of coal has long been an important process for the good of mankind. It is relevant to coke making, the production of briquettes, the formation of specialist carbons such as anodes and other more exotic carbon forms. During heating, volatiles are produced and compounds containing carbon, hydrogen and oxygen are lost. The yield of volatiles and residues (inappropriately called char) depends on the rank of the coal used, the temperature of pyrolysis, and the heating rate. Mathematical models have been devised to account for loss of weight at constant heating rate, gas evolution, plasticity, swelling and changes in density, and other physical properties. Moreover chemical models of pyrolysis have also been devised. When carbon radicals are formed they may polymerize to form, if the correct number of hexagons or pentagons are present, a closed structure, such as the soccerball molecules. An account is given on the work carried out in Australia, at the University of Technology where the scientists were successful in identifying and then preparing buckyballs from coal rather than expensive graphite, first by laser pyrolysis and then by plasma arcing

  4. Molecular dynamics study on the effect of boundary heating rate on the phase change characteristics of thin film liquid

    Energy Technology Data Exchange (ETDEWEB)

    Hasan, Mohammad Nasim, E-mail: nasim@me.buet.ac.bd.com; Morshed, A. K. M. Monjur, E-mail: shavik@me.buet.ac.bd.com; Rabbi, Kazi Fazle, E-mail: rabbi35.me10@gmail.com; Haque, Mominul, E-mail: mominulmarup@gmail.com [Department of Mechanical Engineering, Bangladesh University of Engineering and Technology (BUET) Dhaka-1000 (Bangladesh)

    2016-07-12

    In this study, theoretical investigation of thin film liquid phase change phenomena under different boundary heating rates has been conducted with the help of molecular dynamics simulation. To do this, the case of argon boiling over a platinum surface has been considered. The study has been conducted to get a better understanding of the nano-scale physics of evaporation/boiling for a three phase system with particular emphasis on the effect of boundary heating rate. The simulation domain consisted of liquid and vapor argon atoms placed over a platinum wall. Initially the whole system was brought to an equilibrium state at 90 K with the help of equilibrium molecular dynamics and then the temperature of the bottom wall was increased to a higher temperature (250 K/130 K) over a finite heating period. Depending on the heating period, the boundary heating rate has been varied in the range of 1600×10{sup 9} K/s to 8×10{sup 9} K/s. The variations of argon region temperature, pressure, net evaporation number with respect to time under different boundary heating rates have been determined and discussed. The heat fluxes normal to platinum wall for different cases were also calculated and compared with theoretical upper limit of maximum possible heat transfer to elucidate the effect of boundary heating rate.

  5. Accurate label-free reaction kinetics determination using initial rate heat measurements

    Science.gov (United States)

    Ebrahimi, Kourosh Honarmand; Hagedoorn, Peter-Leon; Jacobs, Denise; Hagen, Wilfred R.

    2015-01-01

    Accurate label-free methods or assays to obtain the initial reaction rates have significant importance in fundamental studies of enzymes and in application-oriented high throughput screening of enzyme activity. Here we introduce a label-free approach for obtaining initial rates of enzyme activity from heat measurements, which we name initial rate calorimetry (IrCal). This approach is based on our new finding that the data recorded by isothermal titration calorimetry for the early stages of a reaction, which have been widely ignored, are correlated to the initial rates. Application of the IrCal approach to various enzymes led to accurate enzyme kinetics parameters as compared to spectroscopic methods and enabled enzyme kinetic studies with natural substrate, e.g. proteases with protein substrates. Because heat is a label-free property of almost all reactions, the IrCal approach holds promise in fundamental studies of various enzymes and in use of calorimetry for high throughput screening of enzyme activity. PMID:26574737

  6. Gaussian model for emission rate measurement of heated plumes using hyperspectral data

    Science.gov (United States)

    Grauer, Samuel J.; Conrad, Bradley M.; Miguel, Rodrigo B.; Daun, Kyle J.

    2018-02-01

    This paper presents a novel model for measuring the emission rate of a heated gas plume using hyperspectral data from an FTIR imaging spectrometer. The radiative transfer equation (RTE) is used to relate the spectral intensity of a pixel to presumed Gaussian distributions of volume fraction and temperature within the plume, along a line-of-sight that corresponds to the pixel, whereas previous techniques exclusively presume uniform distributions for these parameters. Estimates of volume fraction and temperature are converted to a column density by integrating the local molecular density along each path. Image correlation velocimetry is then employed on raw spectral intensity images to estimate the volume-weighted normal velocity at each pixel. Finally, integrating the product of velocity and column density along a control surface yields an estimate of the instantaneous emission rate. For validation, emission rate estimates were derived from synthetic hyperspectral images of a heated methane plume, generated using data from a large-eddy simulation. Calculating the RTE with Gaussian distributions of volume fraction and temperature, instead of uniform distributions, improved the accuracy of column density measurement by 14%. Moreover, the mean methane emission rate measured using our approach was within 4% of the ground truth. These results support the use of Gaussian distributions of thermodynamic properties in calculation of the RTE for optical gas diagnostics.

  7. Liquid-Phase Heat-Release Rates of the Systems Hydrazine-Nitric Acid and Unsymmetrical Dimethylhydrazine-Nitric Acid

    Science.gov (United States)

    Somogyi, Dezso; Feiler, Charles E.

    1960-01-01

    The initial rates of heat release produced by the reactions of hydrazine and unsymmetrical dimethylhydrazine with nitric acid were determined in a bomb calorimeter under conditions of forced mixing. Fuel-oxidant weight ratio and injection velocity were varied. The rate of heat release apparently depended on the interfacial area between the propellants. Above a narrow range of injection velocities representing a critical amount of interfacial area, the rates reached a maximum and were almost constant with injection velocity. The maximum rate for hydrazine was about 70 percent greater than that for unsymmetrical dimethylhydrazine. The total heat released did not vary with mixture ratio over the range studied.

  8. Extension of the master sintering curve for constant heating rate modeling

    Science.gov (United States)

    McCoy, Tammy Michelle

    The purpose of this work is to extend the functionality of the Master Sintering Curve (MSC) such that it can be used as a practical tool for predicting sintering schemes that combine both a constant heating rate and an isothermal hold. Rather than just being able to predict a final density for the object of interest, the extension to the MSC will actually be able to model a sintering run from start to finish. Because the Johnson model does not incorporate this capability, the work presented is an extension of what has already been shown in literature to be a valuable resource in many sintering situations. A predicted sintering curve that incorporates a combination of constant heating rate and an isothermal hold is more indicative of what is found in real-life sintering operations. This research offers the possibility of predicting the sintering schedule for a material, thereby having advanced information about the extent of sintering, the time schedule for sintering, and the sintering temperature with a high degree of accuracy and repeatability. The research conducted in this thesis focuses on the development of a working model for predicting the sintering schedules of several stabilized zirconia powders having the compositions YSZ (HSY8), 10Sc1CeSZ, 10Sc1YSZ, and 11ScSZ1A. The compositions of the four powders are first verified using x-ray diffraction (XRD) and the particle size and surface area are verified using a particle size analyzer and BET analysis, respectively. The sintering studies were conducted on powder compacts using a double pushrod dilatometer. Density measurements are obtained both geometrically and using the Archimedes method. Each of the four powders is pressed into ¼" diameter pellets using a manual press with no additives, such as a binder or lubricant. Using a double push-rod dilatometer, shrinkage data for the pellets is obtained over several different heating rates. The shrinkage data is then converted to reflect the change in relative

  9. International Energy Prices(Exchange Rate and PPP)

    Energy Technology Data Exchange (ETDEWEB)

    Jo, Sung Han; Yoo, Dong Heon [Korea Energy Economics Institute, Euiwang (Korea)

    2000-11-01

    Energy is to be specially important to the Korean economy. In the past the major purpose of Korea's energy policies was to ensure that the energy was supplied at the low cost to encourage and sustain economic development and growth. Therefore, energy prices are distorted by government intervention. And this was the cause of inefficiency in usage of energy. In order to improve the energy efficiency and reduce the environmental impact of energy consumption, new energy pricing should be needed to the energy industry and the Korean economy. It is necessary to compare the domestic energy prices with other countries to improve the energy pricing system including tax, the relative structure of energy price, etc. In order to compare the domestic energy prices to those of other countries, the exchange rate, purchasing power parity and Big Mac index are used for calculation of common currency. We select 12 countries, which are Belgium, France, Germany, Greece, Ireland, Italy, Portugal, Spain, Switzerland, Taiwan, Mexico and England. The oil products(gasoline, diesel, heavy fuel oil and light fuel oil), natural gas and electricity are selected to compare the price. (author). 12 refs., 13 tabs.

  10. Validation Plan of Turbulence Models for Internal Gas Flow Analysis in a Heated Rectangular Riser Duct

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Sin-Yeob; Shin, Dong-Ho; Park, Goon-Cherl; Cho, Hyoung Kyu [Seoul National Univ., Seoul (Korea, Republic of); Kim, Chan-Soo [Korea Atomic Energy Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    VHTR being developed at Korea Atomic Energy Research Institute adopts an air-cooled Reactor Cavity Cooling System (RCCS) incorporating rectangular riser channels to remove the afterheat emitted from the reactor vessel. Because the performance of RCCS is determined by heat removal rate through the RCCS riser, it is important to understand the heat transfer phenomena in the RCCS riser to ensure the safety of the reactor. In the mixed convection, due to the buoyance force induced by temperature and density differences, local flow structure and heat transfer mode near the heated wall have significantly dissimilar characteristics from both forced convection and free convection. In this study, benchmark calculation was conducted to reproduce the previous statements that V2F turbulence model can capture the mixed convection phenomena with the Shehata's experimental data. Then, the necessity of the model validation for the mixed convection phenomena was confirmed with the CFD analyses for the geometry of the prototype RCCS riser. For the purpose of validating the turbulence models for mixed convection phenomena in the heated rectangular riser duct, validation plan with three experimental tests was introduced. Among them, the flow visualization test facility with preserved cross-section geometry was introduced and a preliminary test result was shown.

  11. Theoretical studies of rate chemistry in radiative heating of aerobraking spacecraft

    International Nuclear Information System (INIS)

    Lengsfield, B.H. III.

    1993-04-01

    A multi-reference CI gradient algorithm has been implemented in which the computation of orbital derivatives is efficiently undertaken in the atomic orbital basis. This development circumvents the need to store large numbers of derivatives integrals on disk when one uses multi-reference CI derivative techniques to characterize ground and excited states of polyatomic molecules. With this type of algorithm accurate heats of formation and reactions rate can be ascertained for a much broader range molecular systems. The limitations of these types of studies thus reverts to the feasibility of performing the underlying CI calculation and not the computation of the derivatives of the CI energy. This technique can also be efficiently utilized in the computation of nonadiabatic coupling matrix elements. Finally, the β (B 2 Π - X 2 Π transition) system in NO was investigated. Interest in the B 2 Π state of NO stems from the important role it plays in air after-glow and shock heated air

  12. Heat production rate from radioactive elements in igneous and metamorphic rocks in Eastern Desert, Egypt

    International Nuclear Information System (INIS)

    Abbady, Adel G.E.; El-Arabi, A.M.; Abbady, A.

    2006-01-01

    Radioactive heat-production data of Igneous and Metamorphic outcrops in the Eastern Desert are presented. Samples were analysed using a low level gamma-ray spectrometer (HPGe) in the laboratory. A total of 205 rock samples were investigated, covering all major rock types of the area. The heat-production rate of igneous rocks ranges from 0.11 (basalt) to 9.53 μW m -3 (granite). In metamorphic rocks it varies from 0.28 (serpentinite ) to 0.91 μW m -3 (metagabbro). The contribution due to U is about 51%, as that from Th is 31% and 18% from K. The corresponding values in igneous rocks are 76%, 19% and 5%, respectively. The calculated values showed good agreement with global values except in some areas containing granites

  13. Heat production rate from radioactive elements in igneous and metamorphic rocks in eastern desert, Egypt

    International Nuclear Information System (INIS)

    Abbady, A G.E.; Arabi, A.M.; Abbay, A.

    2005-01-01

    Radioactive heat - production data of igneous and metamorphic rocks cropping out from the eastern desert are presented. Samples were analysed using low level gamma-ray spectrometer (HPGe) in the laboratory. A total of 205 rock samples were investigated, covering all major rock types of the area. The heat-production rate of igneous rocks ranges from 0.11 (basalt) to 9.53 Μ Wm-3 (granite). In metamorphic rocks it varies from 0.28 (serpentinite) to 0.91 (metagabroo) Μ W.m-3. The contribution due to U is about (51%), whereas that of Th (31%) and (18%) by K. The corresponding values in igneous rocks are 76%: 19%: 5%, respectively. The calculated values showed good agreement with global values expect in some areas contained granite rocks

  14. Standard Test Method for Measuring Heat-Transfer Rate Using a Thermal Capacitance (Slug) Calorimeter

    CERN Document Server

    American Society for Testing and Materials. Philadelphia

    2008-01-01

    1.1 This test method describes the measurement of heat transfer rate using a thermal capacitance-type calorimeter which assumes one-dimensional heat conduction into a cylindrical piece of material (slug) with known physical properties. 1.2 This standard does not purport to address all of the safety concerns, if any, associated with its use. It is the responsibility of the user of this standard to establish appropriate safety and health practices and determine the applicability of regulatory limitations prior to use. 1.3 The values stated in SI units are to be regarded as standard. No other units of measurement are included in this standard. Note 1—For information see Test Methods E 285, E 422, E 458, E 459, and E 511.

  15. Radial Pressure Pulse and Heart Rate Variability in Heat- and Cold-Stressed Humans

    Directory of Open Access Journals (Sweden)

    Chin-Ming Huang

    2011-01-01

    Full Text Available This study aims to explore the effects of heat and cold stress on the radial pressure pulse (RPP and heart rate variability (HRV. The subjects immersed their left hand into 45°C and 7°C water for 2 minutes. Sixty healthy subjects (age 25±4 yr; 29 men and 31 women were enrolled in this study. All subjects underwent the supine temperature measurements of the bilateral forearms, brachial arterial blood pressure, HRV and RPP with a pulse analyzer in normothermic conditions, and thermal stresses. The power spectral low-frequency (LF and high-frequency (HF components of HRV decreased in the heat test and increased in the cold test. The heat stress significantly reduced radial augmentation index (AIr (P<.05, but the cold stress significantly increased AIr (P<.01. The spectral energy of RPP did not show any statistical difference in 0∼10 Hz region under both conditions, but in the region of 10∼50 Hz, there was a significant increase (P<.01 in the heat test and a significant decrease in the cold test (P<.01. The changes in AIr induced by heat and cold stress were significantly negatively correlated with the spectral energy in the region of 10∼50 Hz (SE10−50 Hz but not in the region of 0∼10 Hz (SE0−10 Hz. The results demonstrated that the SE10−50 Hz, which only possessed a small percentage in total pulse energy, presented more physiological characteristics than the SE0−10 Hz under the thermal stresses.

  16. Radial Pressure Pulse and Heart Rate Variability in Heat- and Cold-Stressed Humans

    Science.gov (United States)

    Huang, Chin-Ming; Chang, Hsien-Cheh; Kao, Shung-Te; Li, Tsai-Chung; Wei, Ching-Chuan; Chen, Chiachung; Liao, Yin-Tzu; Chen, Fun-Jou

    2011-01-01

    This study aims to explore the effects of heat and cold stress on the radial pressure pulse (RPP) and heart rate variability (HRV). The subjects immersed their left hand into 45°C and 7°C water for 2 minutes. Sixty healthy subjects (age 25 ± 4 yr; 29 men and 31 women) were enrolled in this study. All subjects underwent the supine temperature measurements of the bilateral forearms, brachial arterial blood pressure, HRV and RPP with a pulse analyzer in normothermic conditions, and thermal stresses. The power spectral low-frequency (LF) and high-frequency (HF) components of HRV decreased in the heat test and increased in the cold test. The heat stress significantly reduced radial augmentation index (AIr) (P < .05), but the cold stress significantly increased AIr (P < .01). The spectral energy of RPP did not show any statistical difference in 0 ~ 10 Hz region under both conditions, but in the region of 10 ~ 50 Hz, there was a significant increase (P < .01) in the heat test and a significant decrease in the cold test (P < .01). The changes in AIr induced by heat and cold stress were significantly negatively correlated with the spectral energy in the region of 10 ~ 50 Hz (SE10−50 Hz) but not in the region of 0 ~ 10 Hz (SE0−10 Hz). The results demonstrated that the SE10−50 Hz, which only possessed a small percentage in total pulse energy, presented more physiological characteristics than the SE0−10 Hz under the thermal stresses. PMID:21113292

  17. Review of organic Rankine cycles for internal combustion engine exhaust waste heat recovery

    International Nuclear Information System (INIS)

    Sprouse, Charles; Depcik, Christopher

    2013-01-01

    Escalating fuel prices and future carbon dioxide emission limits are creating a renewed interest in methods to increase the thermal efficiency of engines beyond the limit of in-cylinder techniques. One promising mechanism that accomplishes both objectives is the conversion of engine waste heat to a more useful form of energy, either mechanical or electrical. This paper reviews the history of internal combustion engine exhaust waste heat recovery focusing on Organic Rankine Cycles since this thermodynamic cycle works well with the medium-grade energy of the exhaust. Selection of the cycle expander and working fluid are the primary focus of the review, since they are regarded as having the largest impact on system performance. Results demonstrate a potential fuel economy improvement around 10% with modern refrigerants and advancements in expander technology. -- Highlights: ► This review article focuses on engine exhaust waste heat recovery works. ► The organic Rankine cycle is superior for low to medium exergy heat sources. ► Working fluid and expander selection strongly influence efficiency. ► Several authors demonstrate viable systems for vehicle installation

  18. The effect of texture, heat treatment and elongation rate on stress corrosion cracking in irradiated zircaloy

    International Nuclear Information System (INIS)

    Pettersson, K.; Stany, W.; Hellstrand, E.

    1979-03-01

    Irradiated zircaloy samples with different textures and heat treatments have been tested concerning stress corrosion. Irradiated samples of Zr-1Nb, pure Zr and beta quenched zircaloy have also been investigated. Stress-relieve annealled zircaloy is even after irradiation more sensitive to stress corrosion than recrystallized zircaloy. Zr-1Nb and beta quenched zircaloy are much more sinsitive to stress corrosion than the samples with different textures. As a rule irradiated zircaloy is sensitive to stress corrosion at stresses far below the yield point. The breaking stress decreases with the elongation rate. The extension of cracks is much faster in irradiated zircaloy than in unirradiated zircaloy. There is no simple failure criterium for irradiated zircaloy. However for a certain stress and a certain elongation rate the probability for a failure before this stress is reached with a constant elongation rate can be given. (E.R.)

  19. STEADY-STATE HEAT REJECTION RATES FOR A COAXIAL BOREHOLE HEAT EXCHANGER DURING PASSIVE AND ACTIVE COOLING DETERMINED WITH THE NOVEL STEP THERMAL RESPONSE TEST METHOD

    Directory of Open Access Journals (Sweden)

    Marija Macenić

    2018-01-01

    Full Text Available At three locations in Zagreb, classical and extended thermal response test (TRT was conducted on installed coaxial heat exchangers. With classic TR test, thermogeological properties of the ground and thermal resistance of the borehole were determined at each location. It is seen that thermal conductivity of the ground varies, due to difference in geological profile of the sites. In addition, experimental research of steady-state thermal response step test (SSTRST was carried out to determine heat rejection rates for passive and active cooling in steady state regime. Results showed that heat rejection rate is only between 8-11 W/m, which indicates that coaxial system is not suitable for passive cooling demands. Furthermore, the heat pump in passive cooling mode uses additional plate heat exchanger where there is additional temperature drop of working fluid by approximately 1,5 °C. Therefore, steady-state rejection rate for passive cooling is even lower for a real case project. Coaxial heat exchanger should be always designed for an active cooling regime with an operation of a heat pump compressor in a classical vapour compression refrigeration cycle.

  20. Extreme learning machine: a new alternative for measuring heat collection rate and heat loss coefficient of water-in-glass evacuated tube solar water heaters.

    Science.gov (United States)

    Liu, Zhijian; Li, Hao; Tang, Xindong; Zhang, Xinyu; Lin, Fan; Cheng, Kewei

    2016-01-01

    Heat collection rate and heat loss coefficient are crucial indicators for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, the direct determination requires complex detection devices and a series of standard experiments, wasting too much time and manpower. To address this problem, we previously used artificial neural networks and support vector machine to develop precise knowledge-based models for predicting the heat collection rates and heat loss coefficients of water-in-glass evacuated tube solar water heaters, setting the properties measured by "portable test instruments" as the independent variables. A robust software for determination was also developed. However, in previous results, the prediction accuracy of heat loss coefficients can still be improved compared to those of heat collection rates. Also, in practical applications, even a small reduction in root mean square errors (RMSEs) can sometimes significantly improve the evaluation and business processes. As a further study, in this short report, we show that using a novel and fast machine learning algorithm-extreme learning machine can generate better predicted results for heat loss coefficient, which reduces the average RMSEs to 0.67 in testing.

  1. Thermally radiative three-dimensional flow of Jeffrey nanofluid with internal heat generation and magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Shehzad, S.A., E-mail: ali_qau70@yahoo.com [Department of Mathematics, Comsats Institute of Information Technology, Sahiwal 57000 (Pakistan); Abdullah, Z. [Department of Mathematics, Comsats Institute of Information Technology, Sahiwal 57000 (Pakistan); Alsaedi, A. [Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Faculty of Science, King Abdulaziz University, P. O. Box 80257, Jeddah 21589 (Saudi Arabia); Abbasi, F.M. [Department of Mathematics, Comsats Institute of Information Technology, Islamabad 44000 (Pakistan); Hayat, T. [Nonlinear Analysis and Applied Mathematics (NAAM) Research Group, Faculty of Science, King Abdulaziz University, P. O. Box 80257, Jeddah 21589 (Saudi Arabia); Department of Mathematics, Quaid-I-Azam University 45320, Islamabad 44000 (Pakistan)

    2016-01-01

    This research work addresses the three-dimensional hydromagnetic flow of Jeffrey fluid with nanoparticles. Flow is generated by a bidirectional stretching surface. The effects of thermal radiation and internal heat generation are encountered in energy expressions. More realistic convective boundary conditions at the surface are employed instead of constant surface temperature and mass species conditions. Boundary layer assumptions lead to the governing non-linear mathematical model. Resulting equations through momentum, energy and mass species are made dimensionless using suitable variables. The solution expressions of dimensionless velocities, temperature and nanoparticle concentration have been computed for the convergent series solutions. The impacts of interesting parameters on the dimensionless quantities are displayed and interpreted. The values of physical quantities are computed and analyzed. - Highlights: • Three-dimensional hydromagnetic flow of Jeffrey nanofluid is considered. • Brownian motion and thermophoresis effects are encountered. • Heat transfer analysis is performed with thermal radiation. • Results are plotted and visualized.

  2. Proceedings of the third international steam generator and heat exchanger conference

    International Nuclear Information System (INIS)

    1998-01-01

    The Third International Steam Generator and Heat Exchanger conference had the objective to present the state of knowledge of steam generator performance and life management, and also heat exchanger technology. As this conference followed on from the previous conferences held in Toronto in 1990 and 1994, the emphasis was on recent developments, particularly those of the last 4 years. The conference provided an opportunity to operators, designers and researchers in the field of steam generation associated with electricity generation by nuclear energy to present their findings and exchange ideas. The conference endeavoured to do this over the widest possible range of subject areas, including: general operating experience, life management and fitness for service strategies, maintenance and inspection, thermalhydraulics, vibration, fretting and fatigue, materials, chemistry and corrosion and the regulatory issues

  3. Calculating the heat transfer coefficient of frame profiles with internal cavities

    DEFF Research Database (Denmark)

    Noyé, Peter Anders; Laustsen, Jacob Birck; Svendsen, Svend

    2004-01-01

    . The heat transfer coefficient is determined by two-dimensional numerical calculations and by measurements. Calculations are performed in Therm (LBNL (2001)), which is developed at Lawrence Berkeley National Laboratory, USA. The calculations are performed in accordance with the future European standards...... correspondence between measured and calculated values. Hence, when determining the heat transfer coefficient of frame profiles with internal cavities by calculations, it is necessary to apply a more detailed radiation exchange model than described in the prEN ISO 10077-2 standard. The ISO-standard offers......Determining the energy performance of windows requires detailed knowledge of the thermal properties of their different elements. A series of standards and guidelines exist in this area. The thermal properties of the frame can be determined either by detailed two-dimensional numerical methods...

  4. Proceedings of the third international steam generator and heat exchanger conference

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    The Third International Steam Generator and Heat Exchanger conference had the objective to present the state of knowledge of steam generator performance and life management, and also heat exchanger technology. As this conference followed on from the previous conferences held in Toronto in 1990 and 1994, the emphasis was on recent developments, particularly those of the last 4 years. The conference provided an opportunity to operators, designers and researchers in the field of steam generation associated with electricity generation by nuclear energy to present their findings and exchange ideas. The conference endeavoured to do this over the widest possible range of subject areas,including: general operating experience, life management and fitness for service strategies, maintenance and inspection, thermalhydraulics, vibration, fretting and fatigue, materials, chemistry and corrosion and the regulatory issues.

  5. Financial modeling in medicine: cash flow, basic metrics, the time value of money, discount rates, and internal rate of return.

    Science.gov (United States)

    Lexa, Frank James; Berlin, Jonathan W

    2005-03-01

    In this article, the authors cover tools for financial modeling. Commonly used time lines and cash flow diagrams are discussed. Commonly used but limited terms such as payback and breakeven are introduced. The important topics of the time value of money and discount rates are introduced to lay the foundation for their use in modeling and in more advanced metrics such as the internal rate of return. Finally, the authors broach the more sophisticated topic of net present value.

  6. Propagation of internal stresses in composite materials during heating and cooling according to thermal cycles of welding

    International Nuclear Information System (INIS)

    Gukasyan, L.E.; Belov, V.V.

    1977-01-01

    Investigations of free thermal expansion of a composite material, of fibre and matrix during welding thermal cycle make it possible to estimate mean internal strain and stress in the composite components, as well as the residual internal stress and strain present in the composite material after manufacturing. The samples investigated consisted of nickel-chromium EhI445 alloy, reinforced by tungsten-rhenium alloy fibres. As the composite material was cooled and heated in course of welding, the stress and strain changed their sign twice, the first time upon heating, the second time upon cooling. After complete cooling of the composite material residual stresses in the fibre stay at the proportionality level, while those in the matrix are lower. Experimental evidence of internal stress and strain appearing in the composite material during heating are fairly consistent with calculations in the elastic region, if account is taken of the temperature of internal residual stress relaxation upon heating

  7. Design and simulation of heat exchangers using Aspen HYSYS, and Aspen exchanger design and rating for paddy drying application

    Science.gov (United States)

    Janaun, J.; Kamin, N. H.; Wong, K. H.; Tham, H. J.; Kong, V. V.; Farajpourlar, M.

    2016-06-01

    Air heating unit is one of the most important parts in paddy drying to ensure the efficiency of a drying process. In addition, an optimized air heating unit does not only promise a good paddy quality, but also save more for the operating cost. This study determined the suitable and best specifications heating unit to heat air for paddy drying in the LAMB dryer. In this study, Aspen HYSYS v7.3 was used to obtain the minimum flow rate of hot water needed. The resulting data obtained from Aspen HYSYS v7.3 were used in Aspen Exchanger Design and Rating (EDR) to generate heat exchanger design and costs. The designs include shell and tubes and plate heat exchanger. The heat exchanger was designed in order to produce various drying temperatures of 40, 50, 60 and 70°C of air with different flow rate, 300, 2500 and 5000 LPM. The optimum condition for the heat exchanger were found to be plate heat exchanger with 0.6 mm plate thickness, 198.75 mm plate width, 554.8 mm plate length and 11 numbers of plates operating at 5000 LPM air flow rate.

  8. Relationship between internal medicine program board examination pass rates, accreditation standards, and program size.

    Science.gov (United States)

    Falcone, John L; Gonzalo, Jed D

    2014-01-19

    To determine Internal Medicine residency program compliance with the Accreditation Council for Graduate Medical Education 80% pass-rate standard and the correlation between residency program size and performance on the American Board of Internal Medicine Certifying Examination. Using a cross-sectional study design from 2010-2012 American Board of Internal Medicine Certifying Examination data of all Internal Medicine residency pro-grams, comparisons were made between program pass rates to the Accreditation Council for Graduate Medical Education pass-rate standard. To assess the correlation between program size and performance, a Spearman's rho was calculated. To evaluate program size and its relationship to the pass-rate standard, receiver operative characteristic curves were calculated. Of 372 Internal Medicine residency programs, 276 programs (74%) achieved a pass rate of =80%, surpassing the Accreditation Council for Graduate Medical Education minimum standard. A weak correlation was found between residency program size and pass rate for the three-year period (p=0.19, pInternal Medicine residency programs complied with Accreditation Council for Graduate Medical Education pass-rate standards, a quarter of the programs failed to meet this requirement. Program size is positively but weakly associated with American Board of Internal Medicine Certifying Examination performance, suggesting other unidentified variables significantly contribute to program performance.

  9. Investigation of forced convection heat transfer of supercritical pressure water in a vertically upward internally ribbed tube

    International Nuclear Information System (INIS)

    Wang Jianguo; Li Huixiong; Guo Bin; Yu Shuiqing; Zhang Yuqian; Chen Tingkuan

    2009-01-01

    In the present paper, the forced convection heat transfer characteristics of water in a vertically upward internally ribbed tube at supercritical pressures were investigated experimentally. The six-head internally ribbed tube is made of SA-213T12 steel with an outer diameter of 31.8 mm and a wall thickness of 6 mm and the mean inside diameter of the tube is measured to be 17.6 mm. The experimental parameters were as follows. The pressure at the inlet of the test section varied from 25.0 to 29.0 MPa, and the mass flux was from 800 to 1200 kg/(m 2 s), and the inside wall heat flux ranged from 260 to 660 kW/m 2 . According to experimental data, the effects of heat flux and pressure on heat transfer of supercritical pressure water in the vertically upward internally ribbed tube were analyzed, and the characteristics and mechanisms of heat transfer enhancement, and also that of heat transfer deterioration, were also discussed in the so-called large specific heat region. The drastic changes in thermophysical properties near the pseudocritical points, especially the sudden rise in the specific heat of water at supercritical pressures, may result in the occurrence of the heat transfer enhancement, while the covering of the heat transfer surface by fluids lighter and hotter than the bulk fluid makes the heat transfer deteriorated eventually and explains how this lighter fluid layer forms. It was found that the heat transfer characteristics of water at supercritical pressures were greatly different from the single-phase convection heat transfer at subcritical pressures. There are three heat transfer modes of water at supercritical pressures: (1) normal heat transfer, (2) deteriorated heat transfer with low HTC but high wall temperatures in comparison to the normal heat transfer, and (3) enhanced heat transfer with high HTC and low wall temperatures in comparison to the normal heat transfer. It was also found that the heat transfer deterioration at supercritical pressures was

  10. Effect of heating rate on thermal cracking characteristics and kinetics of Xinjiang oil sand bitumen by TG-FTIR

    Science.gov (United States)

    Hao, Junhui; Zhang, Jinhong; Qiao, Yingyun; Tian, Yuanyu

    2017-08-01

    This work was aimed to investigate effects of heating rate on thermal cracking behaviors, distribution of gaseous products and activation energy of the thermal cracking process of Xinjiang oil sand bitumen (OSB). The thermal cracking experiments of Xinjiang OSB were performed by using thermogravimetric analyzer (TGA) at various heating rates of 10, 20, 50, 80 and 120 K/min. The evolving characteristic of gaseous products produced from the thermal cracking process was evaluated by the Fourier transform infrared spectrometry (FTIR) connected with TG. The kinetic parameters of the thermal cracking process of Xinjiang OSB at each of heating rate were determined by the Coats-Redfern model. The result show that the temperature intervals of DE volatilization stage and main reaction stage, the ((dw/dt) max and Tmax in thermal cracking process of Xinjiang OSB all increased with the increasing heating rate. While the heating rate has not obvious effect on the coke yield of Xinjiang OSB. Furthermore, the maximum absorbance of gaseous products and corresponding temperature became larger as the heating rate increases. The activation energy of this two stage both presented increasing trend with the rising heating rate, while the increasing content of that of DE volatilization stage was weaker compared to that of main reaction stage.

  11. Numerical Studies on Heat Release Rate in Room Fire on Liquid Fuel under Different Ventilation Factors

    Directory of Open Access Journals (Sweden)

    N. Cai

    2012-01-01

    Full Text Available Heat release rate (HRR of the design fire is the most important parameter in assessing building fire hazards. However, HRR in room fire was only studied by computational fluid dynamics (CFD in most of the projects determining fire safety provisions by performance-based design. In contrast to ten years ago, officers in the Far East are now having better knowledge of CFD. Two common questions are raised on CFD-predicted results on describing free boundaries; and on computing grid size. In this work, predicting HRR by the CFD model was justified with experimental room pool fire data reported earlier. The software fire dynamics simulator (FDS version 5 was selected as the CFD simulation tool. Prescribed input heating rate based on the experimental results was used with the liquid fuel model in FDS. Five different free boundary conditions were investigated to predict HRR. Grid sensitivity study was carried out using one stretched mesh and multiple uniform meshes with different grid sizes. As it is difficult to have the entire set of CFD predicted results agreed with experiments, macroscopic flow parameters on the mass flow rate through door opening predicted by CFD were also justified by another four conditions with different ventilation factors.

  12. Decay heat and gamma dose-rate prediction capability in spent LWR fuel

    International Nuclear Information System (INIS)

    Neely, G.J.; Schmittroth, F.

    1982-08-01

    The ORIGEN2 code was established as a valid means to predict decay heat from LWR spent fuel assemblies for decay times up to 10,000 year. Calculational uncertainties ranged from 8.6% to a maximum of 16% at 2.5 years and 300 years cooling time, respectively. The calculational uncertainties at 2.5 years cooling time are supported by experiment. Major sources of uncertainty at the 2.5 year cooling time were identifed as irradiation history (5.7%) and nuclear data together with calculational methods (6.3%). The QAD shielding code was established as a valid means to predict interior and exterior gamma dose rates of spent LWR fuel assemblies. A calculational/measurement comparison was done on two assemblies with different irradiation histories and supports a 35% calculational uncertainty at the 1.8 and 3.0 year decay times studied. Uncertainties at longer times are expected to increase, but not significantly, due to an increased contribution from the actinides whose inventories are assigned a higher uncertainty. The uncertainty in decay heat rises to a maximum of 16% due to actinide uncertainties. A previous study was made of the neutron emission rate from a typical Turkey Point Unit 3, Region 4 spent fuel assembly at 5 years decay time. A conservative estimate of the neutron dose rate at the assembly surface was less than 0.5 rem/hr

  13. First and Second-Law Efficiency Analysis and ANN Prediction of a Diesel Cycle with Internal Irreversibility, Variable Specific Heats, Heat Loss, and Friction Considerations

    Directory of Open Access Journals (Sweden)

    M. M. Rashidi

    2014-04-01

    Full Text Available The variability of specific heats, internal irreversibility, heat and frictional losses are neglected in air-standard analysis for different internal combustion engine cycles. In this paper, the performance of an air-standard Diesel cycle with considerations of internal irreversibility described by using the compression and expansion efficiencies, variable specific heats, and losses due to heat transfer and friction is investigated by using finite-time thermodynamics. Artificial neural network (ANN is proposed for predicting the thermal efficiency and power output values versus the minimum and the maximum temperatures of the cycle and also the compression ratio. Results show that the first-law efficiency and the output power reach their maximum at a critical compression ratio for specific fixed parameters. The first-law efficiency increases as the heat leakage decreases; however the heat leakage has no direct effect on the output power. The results also show that irreversibilities have depressing effects on the performance of the cycle. Finally, a comparison between the results of the thermodynamic analysis and the ANN prediction shows a maximum difference of 0.181% and 0.194% in estimating the thermal efficiency and the output power. The obtained results in this paper can be useful for evaluating and improving the performance of practical Diesel engines.

  14. BRIGITTE, Dose Rate and Heat Source and Energy Flux for Self-Absorbing Rods

    International Nuclear Information System (INIS)

    Jegu, M.; Clement, M.

    1978-01-01

    1 - Nature of physical problem solved: Calculation of dose rate, heat sources or energy flux. The sources are self-absorbing radioactive rods. The shielding consists of blocks of which the cross section can be defined. 2 - Method of solution: Exponential attenuation and build-up factor between source points and detector points. Source integration with error estimate. Automatic or controlled build-up with monitor print-out. 3 - Restrictions on the complexity of the problem: Number of energy points, regions, detector points, abscissa points of the rod, vertical position of the rod, are all limited to ten. The maximum total number of vertical steps is 124

  15. Simultaneous optimization of the cavity heat load and trip rates in linacs using a genetic algorithm

    Directory of Open Access Journals (Sweden)

    Balša Terzić

    2014-10-01

    Full Text Available In this paper, a genetic algorithm-based optimization is used to simultaneously minimize two competing objectives guiding the operation of the Jefferson Lab’s Continuous Electron Beam Accelerator Facility linacs: cavity heat load and radio frequency cavity trip rates. The results represent a significant improvement to the standard linac energy management tool and thereby could lead to a more efficient Continuous Electron Beam Accelerator Facility configuration. This study also serves as a proof of principle of how a genetic algorithm can be used for optimizing other linac-based machines.

  16. Rates of chemical reaction and atmospheric heating during core debris expulsion from a pressurized vessel

    International Nuclear Information System (INIS)

    Powers, D.A.; Tarbell, W.W.; Brockman, J.E.; Pilch, M.

    1986-01-01

    Core debris may be expelled from a pressurized reactor vessel during a severe nuclear reactor accident. Experimental studies of core debris expulsion from pressurized vessels have established that the expelled material can be lofted into the atmosphere of the reactor containment as particulate 0.4 to 2 mm in diameter. These particles will vigorously react with steam and oxygen in the containment atmosphere. Data on such reactions during tests with 80 kg of expelled melt will be reported. A model of the reaction rates based on gas phase mass transport will be described and shown to account for atmospheric heating and aerosol generation observed in the tests

  17. Devolatilization kinetics of woody biomass at short residence times and high heating rates and peak temperatures

    DEFF Research Database (Denmark)

    Johansen, Joakim M.; Gadsbøll, Rasmus; Thomsen, Jesper

    2016-01-01

    This work combines experimental and computational fluid dynamics (CFD) results to derive global kinetics for biomass (pine wood) devolatilization during heating rates on the order of 105Ks-1, bulk flow peak temperatures between 1405 and 1667K, and particle residence times below 0.1s. Experiments......Jmol-1. The accuracy of the derived global kinetics was supported by comparing predictions to experimental results from a 15kW furnace. The work emphasizes the importance of characterizing the temperature history of the biomass particles when deriving pyrolysis kinetics. The present results indicate...

  18. Global distribution of moisture, evaporation-precipitation, and diabatic heating rates

    Science.gov (United States)

    Christy, John R.

    1989-01-01

    Global archives were established for ECMWF 12-hour, multilevel analysis beginning 1 January 1985; day and night IR temperatures, and solar incoming and solar absorbed. Routines were written to access these data conveniently from NASA/MSFC MASSTOR facility for diagnostic analysis. Calculations of diabatic heating rates were performed from the ECMWF data using 4-day intervals. Calculations of precipitable water (W) from 1 May 1985 were carried out using the ECMWF data. Because a major operational change on 1 May 1985 had a significant impact on the moisture field, values prior to that date are incompatible with subsequent analyses.

  19. Thermal Analysis On The Kinetics Of Magnesium-Aluminum Layered Double Hydroxides In Different Heating Rates

    Directory of Open Access Journals (Sweden)

    Hongbo Y.

    2015-06-01

    Full Text Available The thermal decomposition of magnesium-aluminum layered double hydroxides (LDHs was investigated by thermogravimetry analysis and differential scanning calorimetry (DSC methods in argon environment. The influence of heating rates (including 2.5, 5, 10, 15 and 20K/min on the thermal behavior of LDHs was revealed. By the methods of Kissinger and Flynn-Wall-Ozawa, the thermal kinetic parameters of activation energy and pre-exponential factor for the exothermic processes under non-isothermal conditions were calculated using the analysis of corresponding DSC curves.

  20. International finance, Lévy distributions, and the econophysics of exchange rates

    Science.gov (United States)

    Da Silva, Sergio; Matsushita, Raul; Gleria, Iram; Figueiredo, Annibal; Rathie, Pushpa

    2005-06-01

    This paper surveys the developments in the field of international finance, in particular the research of economists on foreign exchange rates. That might be of interest to physicists working on the econophysics of exchange rates. We show how the econophysics agenda might follow naturally from the economists' research. We also present our own work on the econophysics of exchange rates.

  1. 78 FR 41129 - Market Test of Experimental Product - International Merchandise Return Service-Non-Published Rates

    Science.gov (United States)

    2013-07-09

    ...--Non-Published Rates AGENCY: U.S. Postal Service\\TM\\. ACTION: Notice. SUMMARY: The Postal Service hereby gives notice of a market test for International Merchandise Return Service--Non-Published Rates in... Return Service (IMRS) Non-published Rate (NPR) experimental product on August 15, 2013. The Postal...

  2. 14 CFR 399.41 - Zones of limited suspension for international cargo rates.

    Science.gov (United States)

    2010-01-01

    ... TRANSPORTATION (AVIATION PROCEEDINGS) POLICY STATEMENTS STATEMENTS OF GENERAL POLICY Policies Relating to Rates and Tariffs § 399.41 Zones of limited suspension for international cargo rates. (a) Applicability. This section states the Board's policy for suspending rate changes for the transportation of property...

  3. Energy saving in multicomponent separation using an internally heat-integrated distillation column (HIDiC)

    Energy Technology Data Exchange (ETDEWEB)

    Iwakabe, Koichi [Department of Chemical Engineering, Graduate School of Science and Engineering, Tokyo Institute of Technology, 2-12-1, Ookayama, Meguro, Tokyo 152-8552 (Japan); Nakaiwa, Masaru; Huang, Kejin; Ohmori, Takao; Endo, Akira; Yamamoto, Takuji [Energy-Efficient Chemical Systems Group, Research Institute for Innovation in Sustainable Chemistry, National Institute of Advanced Industrial Science and Technology, Tsukuba Central 5, 1-1-1, Higashi, Tsukuba, Ibaraki 305-8565 (Japan); Nakanishi, Toshinari [R and D Department, Kimura Chemical Plants Co., Ltd, 2-1-2, Terajima Kuise, Amagasaki, Hyogo 660-8567 (Japan); Roesjorde, Audun [Department of Chemistry, Norwegian University of Science and Technology, 7491 Tronheim (Norway)

    2006-09-15

    Energy savings by an internally heat-integrated distillation column (HIDiC) for the separation of multicomponent mixtures were studied. The design and the operating variables of a HIDiC were defined for this purpose, and were systematically varied to carry out a sensitivity analysis. Benzene-toluene-p-xylene (BTX) mixture and 12-component hydrocarbons (12HC) mixture were chosen as model systems. Sensitivity analysis showed that the HIDiC is able to reduce energy consumption by about 30% for the BTX system and an even better 50% for the 12HC system. The effects on energy consumption of the design and the operating variables were also examined. (author)

  4. Internal Heating of an IGBT module in a System With a Regenerative AC Drive

    OpenAIRE

    Mabano, Michel

    2016-01-01

    The purpose of this thesis was to understand the internal heating of an IGBT module inside an AC drive in a system with a regenerative unit to it. During the implementation of the lab, various approaches were taken in an effort to collect measurements appropriate to the topic of investigation. The IGBT junction temperature was recorded over a sustained period of time at various speed of the induction motor. The braking torque applied through a second AC drive was varied in order to study...

  5. The rate of plasma heating by harmonic ion cyclotron waves in tokamaks

    International Nuclear Information System (INIS)

    Moslehi-Fard, M.; Sobhanian, S.; Solati-Kia, F.

    2002-01-01

    In tokamaks, the toroidal magnetic field, B φ , is due to the current in coils around plasma, and the poloidal magnetic field B p results from the plasma itself. Usually B φ p , and the combination of these two fields forms a nested set of toroidal magnetic surfaces. The equilibrium Grad-Shafranov equation is investigated and it is shown that the particle products of fusion with different pitch angles on these surfaces have different orbital shapes. In the JET tokamak, the α particles with pitch angle θ smaller than 54.8 deg are passing, those with θ between 54.8 deg and 65.1 deg have trapping-passing orbits but for θ greater than 65.1 deg the orbit has a banana form. Other tokamaks such as Alcator and ITER are also considered. The passing, trapping-passing and banana orbits in these tokamaks are traced. The results obtained from this calculation are analyzed. The wave damping has been investigated produced from interaction with particles, particularly α particles, and the rate of heating for l = 1 to 8 harmonics is plotted. The results of calculation show that heating at the fourth harmonic reaches a maximum. For higher harmonics, the heating does not change much from the fourth harmonic. (author)

  6. Thermal conductance and basal metabolic rate are part of a coordinated system for heat transfer regulation

    Science.gov (United States)

    Naya, Daniel E.; Spangenberg, Lucía; Naya, Hugo; Bozinovic, Francisco

    2013-01-01

    Thermal conductance measures the ease with which heat leaves or enters  an organism's body. Although the analysis of this physiological variable in relation to climatic and ecological factors can be traced to studies by Scholander and colleagues, only small advances have occurred ever since. Here, we analyse the relationship between minimal thermal conductance estimated during summer (Cmin) and several ecological, climatic and geographical factors for 127 rodent species, in order to identify the exogenous factors that have potentially affected the evolution of thermal conductance. In addition, we evaluate whether there is compensation between Cmin and basal metabolic rate (BMR)—in such a way that a scale-invariant ratio between both variables is equal to one—as could be expected from the Scholander–Irving model of heat transfer. Our major findings are (i) annual mean temperature is the best single predictor of mass-independent Cmin. (ii) After controlling for the effect of body mass, there is a strong positive correlation between log10 (Cmin) and log10 (BMR). Further, the slope of this correlation is close to one, indicating an almost perfect compensation between both physiological variables. (iii) Structural equation modelling indicated that Cmin values are adjusted to BMR values and not the other way around. Thus, our results strongly suggest that BMR and thermal conductance integrate a coordinated system for heat regulation in endothermic animals and that summer conductance values are adjusted (in an evolutionary sense) to track changes in BMRs. PMID:23902915

  7. Thermal conductance and basal metabolic rate are part of a coordinated system for heat transfer regulation.

    Science.gov (United States)

    Naya, Daniel E; Spangenberg, Lucía; Naya, Hugo; Bozinovic, Francisco

    2013-09-22

    Thermal conductance measures the ease with which heat leaves or enters an organism's body. Although the analysis of this physiological variable in relation to climatic and ecological factors can be traced to studies by Scholander and colleagues, only small advances have occurred ever since. Here, we analyse the relationship between minimal thermal conductance estimated during summer (Cmin) and several ecological, climatic and geographical factors for 127 rodent species, in order to identify the exogenous factors that have potentially affected the evolution of thermal conductance. In addition, we evaluate whether there is compensation between Cmin and basal metabolic rate (BMR)-in such a way that a scale-invariant ratio between both variables is equal to one-as could be expected from the Scholander-Irving model of heat transfer. Our major findings are (i) annual mean temperature is the best single predictor of mass-independent Cmin. (ii) After controlling for the effect of body mass, there is a strong positive correlation between log10 (Cmin) and log10 (BMR). Further, the slope of this correlation is close to one, indicating an almost perfect compensation between both physiological variables. (iii) Structural equation modelling indicated that Cmin values are adjusted to BMR values and not the other way around. Thus, our results strongly suggest that BMR and thermal conductance integrate a coordinated system for heat regulation in endothermic animals and that summer conductance values are adjusted (in an evolutionary sense) to track changes in BMRs.

  8. Short communication: Effect of heat stress on nonreturn rate of Italian Holstein cows.

    Science.gov (United States)

    Biffani, S; Bernabucci, U; Vitali, A; Lacetera, N; Nardone, A

    2016-07-01

    The data set consisted of 1,016,856 inseminations of 191,012 first, second, and third parity Holstein cows from 484 farms. Data were collected from year 2001 through 2007 and included meteorological data from 35 weather stations. Nonreturn rate at 56 d after first insemination (NR56) was considered. A logit model was used to estimate the effect of temperature-humidity index (THI) on reproduction across parities. Then, least squares means were used to detect the THI breakpoints using a 2-phase linear regression procedure. Finally, a multiple-trait threshold model was used to estimate variance components for NR56 in first and second parity cows. A dummy regression variable (t) was used to estimate NR56 decline due to heat stress. The NR56, both for first and second parity cows, was significantly (unfavorable) affected by THI from 4 d before 5 d after the insemination date. Additive genetic variances for NR56 increased from first to second parity both for general and heat stress effect. Genetic correlations between general and heat stress effects were -0.31 for first parity and -0.45 for second parity cows. Copyright © 2016 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

  9. Internal Thermal Control System Hose Heat Transfer Fluid Thermal Expansion Evaluation Test Report

    Science.gov (United States)

    Wieland, P. O.; Hawk, H. D.

    2001-01-01

    During assembly of the International Space Station, the Internal Thermal Control Systems in adjacent modules are connected by jumper hoses referred to as integrated hose assemblies (IHAs). A test of an IHA has been performed at the Marshall Space Flight Center to determine whether the pressure in an IHA filled with heat transfer fluid would exceed the maximum design pressure when subjected to elevated temperatures (up to 60 C (140 F)) that may be experienced during storage or transportation. The results of the test show that the pressure in the IHA remains below 227 kPa (33 psia) (well below the 689 kPa (100 psia) maximum design pressure) even at a temperature of 71 C (160 F), with no indication of leakage or damage to the hose. Therefore, based on the results of this test, the IHA can safely be filled with coolant prior to launch. The test and results are documented in this Technical Memorandum.

  10. Effect of moisture content on the R{sub 70} self-heating rate of Callide coal

    Energy Technology Data Exchange (ETDEWEB)

    Beamish, B. Basil; Hamilton, Garth R. [School of Engineering, The University of Queensland, St Lucia, Qld 4072 (Australia)

    2005-10-17

    Strip samples from the Boundary Hill pit at Callide have been tested in an adiabatic oven to assess the effect of moisture on the R{sub 70} self-heating rate of coal. The two strip samples tested had R{sub 70} self-heating rate values of 10.23 and 8.61 {sup o}C/h. As the moisture content of the coal was progressively increased, from the dry state of the test, the R{sub 70} value decreased dramatically. At approximately 40-50% of the moisture holding capacity of the coal, the self-heating rate becomes measurable. Above this critical level of moisture content, the heat produced by oxidation is dissipated by moisture evaporation and coal self-heating is significantly delayed. (author)

  11. A study on the characteristics of the decay heat removal capacity for a large thermal rated LMR design

    International Nuclear Information System (INIS)

    Uh, J. H.; Kim, E. K.; Kim, S. O.

    2003-01-01

    The design characteristics and the decay heat removal capacity according to the type of DHR (Decay Heat Removal) system in LMR are quantitatively analyzed, and the general relationship between the rated core thermal power and decay heat removal capacity is created in this study. Based on these analyses results, a feasibility of designing a larger thermal rating KALIMER plant is investigated in view of decay heat removal capacity, and DRC (Direct Reactor Cooling) type DHR system which rejects heat from the reactor pool to air is proper to satisfy the decay heat removal capacity for a large thermal rating plant above 1,000 MWth. Some defects, however, including the heat loss under normal plant operation and the lack of reliance associated with system operation should be resolved in order to adopt the total passive concept. Therefore, the new concept of DHR system for a larger thermal rating KALIMER design, named as PDRC (passive decay heat removal circuit), is established in this study. In the newly established concept of PDRC, the Na-Na heat exchanger is located above the sodium cold pool and is prevented from the direct sodium contact during normal operation. This total passive feature has the superiority in the aspect of the minimizing the normal heat loss and the increasing the operation reliance of DHR system by removing either any operator action or any external operation signal associated with system operation. From this study, it is confirmed that the new concept of PDRC is useful to the designing of a large thermal rating power plant of KALIMER-600 in view of decay heat removal capability

  12. Effect of continuous hemofiltration on internal environment and survival rate of severe heatstroke dogs with shock

    Directory of Open Access Journals (Sweden)

    Guang-ming CHEN

    2011-08-01

    Full Text Available Objective To explore the effect of continuous hemofiltration(CHF on internal environment and survival rate of severe heatstroke dogs with shock.Methods Sixteen healthy male dogs were randomly divided into heatshock group(HS group,n=8 and continuous hemofiltration group(CHF group,n=8.Severe heatstroke model was established by applying high temperature to whole body,and then the animals were removed from the heating cabin as soon as they presented manifestations of shock.Dogs of HS group were put into an ordinary environment,while dogs of CHF group received CHF treatment.The core temperature(Tc,mean arterial pressure(MAP,blood gas analysis,serum electrolytes and survival rate of dogs in two groups were observed.Results The time from heat exposure to shock was 107.0±28.5min and 111.4±22.2min in HS group and CHF group respectively(t=-0.354,P=0.729.The Tc in CHF group declined to normal level 15 to 30 minitues after CHF treatment,while the Tc in HS group remained at a level higher than that before heat exposure at 90min after shock.The Tc of two groups showed significant difference at each time point after shock(P < 0.01.The MAP of both groups was obviously lowered than that before heatstroke.The MAP of CHF group raised gradually 30 min after treatment,while the MAP of HS group rose very slowly,and it was significantly lower than that of CHF group at each time point after 45min(P < 0.05,P < 0.01.All the dogs in both groups manifested hyperventilation and respiratory alkalosis when shock appeared.After shock,respiratory alkalosis in HS group gradually became metabolic acidosis,with some animals manifested combined metabolic and respiratory acidosis because of respiratory decompensation,while the blood gas levels in CHF group recovered to normal gradually.The blood gas levels of two groups showed significant difference at each time point after shock(P < 0.05,P < 0.01.Hypernatremia,hyperchloraemia and hyperpotassaemia were found in all animals of both

  13. Experimental constraints on heating and cooling rates of refractory inclusions in the early solar system

    International Nuclear Information System (INIS)

    Boynton, W.V.

    1987-01-01

    The refractory inclusions in carbonaceous chondrites were the subject of considerable interest since their discovery. These inclusions contain minerals that are predicted to be some of the earliest condensates from the solar nebula, and contain a plethora of isotopic anomalies of unknown origin. Of particular interest are those coarse-grained inclusions that contain refractory metal particles (Fe, Ni, Pt, Ru, Os Ir). Experimental studies of these inclusions in terrestrial laboratories are, however, complicated because the dense particles tend to settle out of a molten or partially molten silicate material. Heating experiments in the Space Station technology and microgravity in order to observe the effects of metal nuggets (which may act as heterogeneous nucleation sites) on nucleation rates in silicate systems and to measure simultaneously the relative volatilization rate of siderophile and lithophile species. Neither experiment is possible in the terrestrial environment

  14. Assessment of potential Rio Grande do Norte, Brazil, clays when subjected to high rates of heating

    International Nuclear Information System (INIS)

    Filgueira, R.L.; Pereira, L.M.; Dutra, R.P.S.; Nascimento, R.M.

    2009-01-01

    In this work we study three clays of the state of Rio Grande do Norte, Brazil, to evaluate the potential them when subjected to high rates of heating. The samples were formed by pressing and subject to rates of 5 deg C / min, 10 deg C / min and 15 deg C / min, with temperature of 950 deg C. This study determined the technological properties of the samples. The mineralogical composition was identified by X-ray diffraction. The chemical composition was determined by Xray fluorescence. The Atterberg limits, were used to classify the samples on the plasticity. Were also performed: dilatometry, size analysis and scanning electron microscopy. The examination of the processing variables and the intrinsic characteristics of each material indicates that the RX clay showed the best results for the manufacture of blocks and tiles. The techniques used in this study were efficient and the initial objectives were achieved. (author)

  15. Instantaneous Metabolic Cost of Walking: Joint-Space Dynamic Model with Subject-Specific Heat Rate.

    Directory of Open Access Journals (Sweden)

    Dustyn Roberts

    Full Text Available A subject-specific model of instantaneous cost of transport (ICOT is introduced from the joint-space formulation of metabolic energy expenditure using the laws of thermodynamics and the principles of multibody system dynamics. Work and heat are formulated in generalized coordinates as functions of joint kinematic and dynamic variables. Generalized heat rates mapped from muscle energetics are estimated from experimental walking metabolic data for the whole body, including upper-body and bilateral data synchronization. Identified subject-specific energetic parameters-mass, height, (estimated maximum oxygen uptake, and (estimated maximum joint torques-are incorporated into the heat rate, as opposed to the traditional in vitro and subject-invariant muscle parameters. The total model metabolic energy expenditure values are within 5.7 ± 4.6% error of the measured values with strong (R2 > 0.90 inter- and intra-subject correlations. The model reliably predicts the characteristic convexity and magnitudes (0.326-0.348 of the experimental total COT (0.311-0.358 across different subjects and speeds. The ICOT as a function of time provides insights into gait energetic causes and effects (e.g., normalized comparison and sensitivity with respect to walking speed and phase-specific COT, which are unavailable from conventional metabolic measurements or muscle models. Using the joint-space variables from commonly measured or simulated data, the models enable real-time and phase-specific evaluations of transient or non-periodic general tasks that use a range of (aerobic energy pathway similar to that of steady-state walking.

  16. Fitness-related differences in the rate of whole-body evaporative heat loss in exercising men are heat-load dependent.

    Science.gov (United States)

    Lamarche, Dallon T; Notley, Sean R; Louie, Jeffrey C; Poirier, Martin P; Kenny, Glen P

    2018-01-01

    What is the central question of this study? Aerobic fitness modulates heat loss, but the heat-load threshold at which fitness-related differences in heat loss occur in young healthy men remains unclear. What is the main finding and its importance? We demonstrate using direct calorimetry that aerobic fitness modulates heat loss in a heat-load-dependent manner, with fitness-related differences occurring between young men who have low and high fitness when the heat load is ∼≥500 W. Although aerobic fitness has been known for some time to modulate heat loss, our findings define the precise heat-load threshold at which fitness-related differences occur. The effect of aerobic fitness (defined as rate of peak oxygen consumption) on heat loss during exercise is thought to be related to the level of heat stress. However, it remains unclear at what combined exercise and environmental (net) heat-load threshold these fitness-related differences occur. To identify this, we assessed whole-body heat exchange (dry and evaporative) by direct calorimetry in young (22 ± 3 years) men matched for physical characteristics with low (Low-fit; 39.8 ± 2.5 ml O 2  kg -1  min -1 ), moderate (Mod-fit; 50.9 ± 1.2 ml O 2  kg -1  min -1 ) and high aerobic fitness (High-fit; 62.0 ± 4.4 ml O 2  kg -1  min -1 ; each n = 8), during three 30 min bouts of cycling in dry heat (40°C, 12% relative humidity) at increasing rates of metabolic heat production of 300 (Ex1), 400 (Ex2) and 500 W (Ex3), each followed by a 15 min recovery period. Each group was exposed to a similar net heat load (metabolic plus ∼100 W dry heat gain; P = 0.83) during each exercise bout [∼400 (Ex1), ∼500 (Ex2) and ∼600 W (Ex3); P fit (Ex2, 466 ± 21 W; Ex3, 557 ± 26 W) compared with the Low-fit group (Ex2, 439 ± 22 W; Ex3, 511 ± 20 W) during Ex2 and Ex3 (P ≤ 0.03). Conversely, evaporative heat loss for the Mod-fit group did not differ from either the High-fit or Low

  17. Solutions obtained to international heat transfer benchmarking problems for nuclear fuel casks using Q/TRAN

    International Nuclear Information System (INIS)

    Sanchez, L.C.

    1987-02-01

    In 1985 Sandia National Laboratories participated in the Nuclear Energy Agency Committee on Reactor Physics (NEACRP) Specialists' Meeting on Heat Transfer Assessment of Transportation Packages. The objective of the meeting was to establish a set of model problems for use in comparing the performance of thermal analysis computer codes that may be used in the design of nuclear fuel shipping casks. The selected problems are to be used to compare code results for the thermal phenomena of conduction, convection, and radiation in cask-like problems. Two model problems were used in this study. The first problem required the determination of the steady-state temperatures of a 16 x 16 array of heated and unheated pins (representing fuel and control rod positions) of a simulated PWR fuel assembly. The second problem required the determination of transient temperatures of a finned surface (representing the external surface of a cask) subjected to an internal heat flux and to an external engulfing fire. Solutions to the problems were obtained with the code ''Q/TRAN.'' Solutions and descriptions of the necessary modeling techniques are given in this report

  18. Method for calculating internal radiation and ventilation with the ADINAT heat-flow code

    International Nuclear Information System (INIS)

    Butkovich, T.R.; Montan, D.N.

    1980-01-01

    One objective of the spent fuel test in Climax Stock granite (SFTC) is to correctly model the thermal transport, and the changes in the stress field and accompanying displacements from the application of the thermal loads. We have chosen the ADINA and ADINAT finite element codes to do these calculations. ADINAT is a heat transfer code compatible to the ADINA displacement and stress analysis code. The heat flow problem encountered at SFTC requires a code with conduction, radiation, and ventilation capabilities, which the present version of ADINAT does not have. We have devised a method for calculating internal radiation and ventilation with the ADINAT code. This method effectively reproduces the results from the TRUMP multi-dimensional finite difference code, which correctly models radiative heat transport between drift surfaces, conductive and convective thermal transport to and through air in the drifts, and mass flow of air in the drifts. The temperature histories for each node in the finite element mesh calculated with ADINAT using this method can be used directly in the ADINA thermal-mechanical calculation

  19. Dual-cycle power plant with internal and external heating of a gas turbine circuit

    International Nuclear Information System (INIS)

    Strach, L.

    1976-01-01

    The present proposal, after a preceding invention by the same inventor, aims at making possible the increased use of gas turbines in nuclear and coal-fired power plants. This is to be achieved by bringing the temperature of the combustion easily from a maximum of 900 0 C, as may be supplied, e.g., by the cooling media of nuclear reactors, up to the 1,700 to 2,000 0 C required as inlet temperature for gas turbines, with the aid of a fossil-fired recuperator. In fossil and nuclear power plants, gas turbines will more and more substitute steam turbines which affect the environment because of their high waste-heat losses. In coal power plants, only that part of the coal will be gasified whose resulting gas causes internal combustion within the furnace, while the remaining part of the coal is used for external combustion in a tabular heater. In a nuclear power plant, undisturbed maximum generation of electric power is to be achieved, even at reactor outages and shutdown periods for refuelling and maintenance, by almost inertia-free increase of the fossil fuel supply to the furnace (provided an extension of the latter for the capacity of heating the combustion air from room temperature till 1,700 to 2,000 0 C). The hazard of ruptures in the primary heat exchanging system is very low, because it is operated with a relative pressure of nearly zero between reactor coolant and gas turbine circuit. (RW) [de

  20. Full text publication rates of studies presented at an international emergency medicine scientific meeting.

    Science.gov (United States)

    Chan, Jannet W M; Graham, Colin A

    2011-09-01

    The publication rate of full text papers following an abstract presentation at a medical conference is variable, and few studies have examined the situation with respect to international emergency medicine conferences. This retrospective study aimed to identify the publication rate of abstracts presented at the 2006 International Conference on Emergency Medicine (ICEM) held in Halifax, Canada. The full text publication rate was 33.2%, similar to previous emergency medicine meetings. English language barriers may play a role in the low publication rate seen.

  1. The influence of heating rate on reheat-cracking in a commercial 2 1/4Cr1Mo steel

    International Nuclear Information System (INIS)

    Hippsley, C.A.

    1983-03-01

    The effects of elevated heating rate on stress-relief cracking in a commercial 2 1/4 Cr1Mo steel have been investigated. A SEN bend-specimen stress-relaxation test was used to assess reheat cracking susceptibility and fracture mechanisms for an initial post-weld heating rate of 1000 Kh - 1 . Two factors controlling the influence of heating rate on the final severity of cracking were identified, i.e. the rate of stress-relaxation with respect to temperature, and the time available for crack-growth. The factors were found to counteract each other, but in the case of commercial 2 1/4 Cr1Mo steel, the crack-growth factor outweighed the relaxation factor, resulting in a reduction in the propensity to stress-relief cracking at the elevated heating rate. However, by reference to the results of a separate investigation concerning A508/2 MnMoNiCr steel it was demonstrated that the balance between these two factors may be reversed in other alloy systems, with the consequence that reheat cracking is exacerbated by increasing the initial heating rate. A computer model was addressed to the stress-relaxation test conditions using data from the commercial 2 1/4 Cr1Mo steel. The model predictions exhibited reasonable agreement with experimental test results for both 100 Kh - 1 and 1000 Kh - 1 heating rates. (author)

  2. Examination of the optimal operation of building scale combined heat and power systems under disparate climate and GHG emissions rates

    International Nuclear Information System (INIS)

    Howard, B.; Modi, V.

    2017-01-01

    Highlights: • CHP attributable reductions, not viable by electric generation alone, are defined. • Simplified operating strategy heuristics are optimal under specific circumstances. • Phosphoric acid fuel cells yield the largest reductions except in the extremes. • Changes in baseline emissions affect the optimal system capacity and operating hours. - Abstract: This work aims to elucidate notions concerning the ideal operation and greenhouse gas (GHG) emissions benefits of combined heat and power (CHP) systems by investigating how various metrics change as a function of the GHG emissions from the underlying electricity source, building use type and climate. Additionally, a new term entitled “CHP Attributable” reductions is introduced to quantify the benefits from the simultaneous use of thermal and electric energy, removing benefits achieved solely from fuel switching and generating electricity more efficiently. The GHG emission benefits from implementing internal combustion engine, microturbines, and phosphoric acid (PA) fuel cell based CHP systems were evaluated through an optimization approach considering energy demands of prototypical hospital, office, and residential buildings in varied climates. To explore the effect of electric GHG emissions rates, the ideal operation of the CHP systems was evaluated under three scenarios: “High” GHG emissions rates, “Low” GHG emissions rates, and “Current” GHG emissions rate for a specific location. The analysis finds that PA fuel cells achieve the highest GHG emission reductions in most cases considered, though there are exceptions. Common heuristics, such as electric load following and thermal load following, are the optimal operating strategy under specific conditions. The optimal CHP capacity and operating hours both vary as a function of building type, climate and GHG emissions rates from grid electricity. GHG emissions reductions can be as high as 49% considering a PA fuel cell for a

  3. Analysis of read-out heating rate effects on the glow peaks of TLD-100 using WinGCF software

    Energy Technology Data Exchange (ETDEWEB)

    Bauk, Sabar, E-mail: sabar@usm.my [Physics Section, School of Distance Education, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Hussin, Siti Fatimah [School of Physics, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Alam, Md. Shah [Physics Section, School of Distance Education, Universiti Sains Malaysia, 11800 USM, Penang (Malaysia); Physics Department, Shahjalal University of Science and Technology, Sylhet (Bangladesh)

    2016-01-22

    This study was done to analyze the effects of the read-out heating rate on the LiF:Mg,Ti (TLD-100) thermoluminescent dosimeters (TLD) glow peaks using WinGCF computer software. The TLDs were exposed to X-ray photons with a potential difference of 72 kVp and 200 mAs in air and were read-out using a Harshaw 3500 TLD reader. The TLDs were read-out using four read-out heating rates at 10, 7, 4 and 1 °C s{sup −1}. It was observed that lowering the heating rate could separate more glow peaks. The activation energy for peak 5 was found to be lower than that for peak 4. The peak maximum temperature and the integral value of the main peak decreased as the heating rate decreases.

  4. Numerical renormalization group calculation of impurity internal energy and specific heat of quantum impurity models

    Science.gov (United States)

    Merker, L.; Costi, T. A.

    2012-08-01

    We introduce a method to obtain the specific heat of quantum impurity models via a direct calculation of the impurity internal energy requiring only the evaluation of local quantities within a single numerical renormalization group (NRG) calculation for the total system. For the Anderson impurity model we show that the impurity internal energy can be expressed as a sum of purely local static correlation functions and a term that involves also the impurity Green function. The temperature dependence of the latter can be neglected in many cases, thereby allowing the impurity specific heat Cimp to be calculated accurately from local static correlation functions; specifically via Cimp=(∂Eionic)/(∂T)+(1)/(2)(∂Ehyb)/(∂T), where Eionic and Ehyb are the energies of the (embedded) impurity and the hybridization energy, respectively. The term involving the Green function can also be evaluated in cases where its temperature dependence is non-negligible, adding an extra term to Cimp. For the nondegenerate Anderson impurity model, we show by comparison with exact Bethe ansatz calculations that the results recover accurately both the Kondo induced peak in the specific heat at low temperatures as well as the high-temperature peak due to the resonant level. The approach applies to multiorbital and multichannel Anderson impurity models with arbitrary local Coulomb interactions. An application to the Ohmic two-state system and the anisotropic Kondo model is also given, with comparisons to Bethe ansatz calculations. The approach could also be of interest within other impurity solvers, for example, within quantum Monte Carlo techniques.

  5. Sintering of porous silver compacts at controlled heating rates in oxygen or argon

    International Nuclear Information System (INIS)

    Oliber, E.A; Cugno, C; Moreno, M; Esquivel, M; Haberkon, N; Fiscina, J.E; Gonzalez Oliver, C.J.R

    2002-01-01

    A submicronic (- 0.4μm grain size) spherical silver powder was mixed with 2wt% PVB and pressed into pellets (body A) of relative density (ρr) close to 0.54. The pellets were given a heat treatment at 235 o C for 4 hours (body B) in static air, after which the ρr values were increased by ∼2%. The preheated pellets (B) were densified in a vertical differential dilatometer, fitted with a silica head, at heating rates (hr) of 2, 4 and 10 o C min -1 under Ar or O 2 pure atmospheres. The total lineal densification [Δl(T)/lo, ΔI=Io-1(T) instantaneous thickness and lo: the initial thickness of the pellet] of the Ag-skeletons (B, of similar starting porosity) varied significantly upon changing either the (hr) or the atmosphere. It ranged from 8 to 12% giving still porous bodies of ρr∼0.80. After a small densification (stage (i)) each curve showed a clear Ti ( o C ) at which the densification (AD(T) exhibited a rapid increase (jump; stage (ii), and had a characteristic peak in densification rate (DR(T)). Then the AD continued by another mechanism (stage (iii)), related to grain growth, till the densification rate started to decrease probably due to densification (stage (iv)) of closed pores located at 4-grain corners. For every atmosphere the Ti increased with heating rate, and the Ti values for O 2 were 79- 105 o C lower than those for Ar. From DR kinetics analysis it is concluded that under O 2 stage (ii) is due to grain boundary diffusivity (gb) whereas for stage (iii) the volume (vol) diffusion is the main process. From detail densification fits it is shown for stage (iii) there is an initial contribution to densification coming up from an initial stage controlled by (gb) diffusion, and that the main process is still the intermediate stage with simultaneous grain growth controlled by volume self-diffusivity. For the Ar case the whole densification range appears to be controlled by (gb) diffusivity. Some impurity contamination of the Ag could produce a (gb

  6. A combined thermodynamic cycle based on methanol dissociation for IC (internal combustion) engine exhaust heat recovery

    International Nuclear Information System (INIS)

    Fu, Jianqin; Liu, Jingping; Xu, Zhengxin; Ren, Chengqin; Deng, Banglin

    2013-01-01

    In this paper, a novel approach for exhaust heat recovery was proposed to improve IC (internal combustion) engine fuel efficiency and also to achieve the goal for direct usage of methanol as IC engine fuel. An open organic Rankine cycle system using methanol as working medium is coupled to IC engine exhaust pipe for exhaust heat recovery. In the bottom cycle, the working medium first undergoes dissociation and expansion processes, and is then directed back to IC engine as fuel. As the external bottom cycle and the IC engine main cycle are combined together, this scheme forms a combined thermodynamic cycle. Then, this concept was applied to a turbocharged engine, and the corresponding simulation models were built for both of the external bottom cycle and the IC engine main cycle. On this basis, the energy saving potential of this combined cycle was estimated by parametric analyses. Compared to the methanol vapor engine, IC engine in-cylinder efficiency has an increase of 1.4–2.1 percentage points under full load conditions, while the external bottom cycle can increase the fuel efficiency by 3.9–5.2 percentage points at the working pressure of 30 bar. The maximum improvement to the IC engine global fuel efficiency reaches 6.8 percentage points. - Highlights: • A combined thermodynamic cycle using methanol as working medium for IC engine exhaust heat recovery is proposed. • The external bottom cycle of exhaust heat recovery and IC engine working cycle are combined together. • IC engine fuel efficiency could be improved from both in-cylinder working cycle and external bottom cycle. • The maximum improvement to the IC engine global fuel efficiency reaches 6.8 percentage points at full load

  7. Background internal dose rates of earthworm and arthropod species in the forests of Aomori, Japan

    International Nuclear Information System (INIS)

    Ohtsuka, Yoshihito; Takaku, Yuichi; Hisamatsu, Shun'ichi

    2013-01-01

    We measured naturally occurring radionuclides in samples from an earthworm species and 11 arthropod species collected in coniferous forests in Rokkasho, Aomori, Japan, to assess background internal radiation dose rates. The rates were calculated from the measured concentrations of the radionuclides and dose coefficients from the literature. The mean internal dose rate of composite earthworm samples was 0.35 μGy h -1 , whereas the mean dose rates of the arthropod samples ranged from 36 nGy h -1 to 0.79 μGy h -1 . Polonium-210 was the radionuclide with the highest contribution to the internal dose rate for all the species, except the longhorn beetle. (author)

  8. The impact of risk management on internal and sustainable growth rate: Evidence from Tehran Stock Exchange

    Directory of Open Access Journals (Sweden)

    Hamid Reza Vakili Fard

    2014-09-01

    Full Text Available Measuring the relative risk of firms has been an open discussion among researchers. There are many studies on learning how leverage may influence on growth of the firms. This article reviews the relationship between risk management, internal and sustainable growth of accepted companies in Tehran stock exchange. The survey considers three types of risks including operating, financial and compound and investigates their relationships with internal growth rate as well as sustainable growth rate. Using some regression techniques, the study has determined negative and meaningful relationships between different types of leverage on side and internal as well as sustainable growth on the other side.

  9. The effect of temperature and heating rate on char properties obtained from solar pyrolysis of beech wood.

    Science.gov (United States)

    Zeng, Kuo; Minh, Doan Pham; Gauthier, Daniel; Weiss-Hortala, Elsa; Nzihou, Ange; Flamant, Gilles

    2015-04-01

    Char samples were produced from pyrolysis in a lab-scale solar reactor. The pyrolysis of beech wood was carried out at temperatures ranging from 600 to 2000°C, with heating rates from 5 to 450°C/s. CHNS, scanning electron microscopy analysis, X-ray diffractometry, Brunauer-Emmett-Teller adsorption were employed to investigate the effect of temperature and heating rate on char composition and structure. The results indicated that char structure was more and more ordered with temperature increase and heating rate decrease (higher than 50°C/s). The surface area and pore volume firstly increased with temperature and reached maximum at 1200°C then reduced significantly at 2000°C. Besides, they firstly increased with heating rate and then decreased slightly at heating rate of 450°C/s when final temperature was no lower than 1200°C. Char reactivity measured by TGA analysis was found to correlate with the evolution of char surface area and pore volume with temperature and heating rate. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. Fitness-related differences in the rate of whole-body total heat loss in exercising young healthy women are heat-load dependent.

    Science.gov (United States)

    Lamarche, Dallon T; Notley, Sean R; Poirier, Martin P; Kenny, Glen P

    2018-03-01

    What is the central question of this study? Aerobic fitness modulates heat loss, albeit the heat load at which fitness-related differences occur in young healthy women remains unclear. What is the main finding and its importance? We demonstrate using direct calorimetry that fitness modulates heat loss in a heat-load dependent manner, with differences occurring between young women of low and high fitness and matched physical characteristics when the metabolic heat load is at least 400 W in hot, dry conditions. Although fitness has been known for some time to modulate heat loss, our findings define the metabolic heat load at which fitness-related differences occur. Aerobic fitness has recently been shown to alter heat loss capacity in a heat-load dependent manner in young men. However, given that sex-related differences in heat loss capacity exist, it is unclear whether this response is consistent in women. We therefore assessed whole-body total heat loss in young (21 ± 3 years old) healthy women matched for physical characteristics, but with low (low-fit; 35.8 ± 4.5 ml O 2  kg -1  min -1 ) or high aerobic fitness (high-fit; 53.1 ± 5.1 ml O 2  kg -1  min -1 ; both n = 8; indexed by peak oxygen consumption), during three 30 min bouts of cycling performed at increasing rates of metabolic heat production of 250 (Ex1), 325 (Ex2) and 400 W (Ex3), each separated by a 15 min recovery, in hot, dry conditions (40°C, 11% relative humidity). Whole-body total heat loss (evaporative ± dry heat exchange) and metabolic heat production were measured using direct and indirect calorimetry, respectively. Body heat content was measured as the temporal summation of heat production and loss. Total heat loss did not differ during Ex1 (low-fit, 215 ± 16 W; high-fit, 231 ± 20 W; P > 0.05) and Ex2 (low-fit, 278 ± 15 W; high-fit, 301 ± 20 W; P > 0.05), but was lower in the low-fit (316 ± 21 W) compared with the high-fit women (359 ± 32

  11. Uranium, Thorium and Potassium concentrations and volumetric heat production rates at the eastern border of the Parana basin

    International Nuclear Information System (INIS)

    Andrade, Telma C.Q.; Ribeiro, Fernando B.

    1997-01-01

    Uranium, thorium and potassium concentrations were measured and volumetric heat production rates were calculated for rocks from the exposed basement at the eastern-southeastern border of the Parana Basin between 23 deg S and 32 deg S. Heat generating element concentration data available in the literature were also used when possible, for volumetric heat production calculations. The uranium concentrations vary from below determination limit (0.51 ppm) and 16 ppm whereas the thorium concentrations vary from below the determination limit (1.26 ppm) and 68 ppm, and K concentrations vary between 0.08% and 5.6%. Volumetric heat production rates vary between 0.07 μW/m 3 to 6.2 μW/m 3 , and the obtained results show a variable heat generation rate with high heat producing bodies scattered along this Parana Basin border. The higher observed values concentrate in the Ribeira fold belt at about 23 deg S and between 30 deg S and 32 deg S in the Down Feliciano fold belt. Isolated high heat production rates can also be observed between 26 deg S and 28 deg S. (author). 11 refs., 3 tabs

  12. 78 FR 1277 - International Product Change-Global Expedited Package Services-Non-Published Rates

    Science.gov (United States)

    2013-01-08

    ... POSTAL SERVICE International Product Change--Global Expedited Package Services-- Non-Published...-- Non-Published Rates 4 (GEPS-NPR 4) to the Competitive Products List. DATES: Effective date: January 8... add Global Expedited Package Services-- Non-Published Rates 4 (GEPS-NPR 4) to the Competitive Products...

  13. International interest rate convergence: a survey of the issues and evidence

    OpenAIRE

    Charles Pigott

    1993-01-01

    World financial markets have become substantially integrated over the last two decades. Contrary to widespread expectations, however, this integration has not led to any greater convergence of interest rates across countries. This article examines why convergence has not occurred and more generally what financial integration does—and does not—mean for international interest rate relations.

  14. Stochastic Discount Factor Approach to International Risk-Sharing: Evidence from Fixed Exchange Rate Episodes

    NARCIS (Netherlands)

    Hadzi-Vaskov, M.; Kool, C.J.M.

    2007-01-01

    This paper presents evidence of the stochastic discount factor approach to international risk-sharing applied to fixed exchange rate regimes. We calculate risk-sharing indices for two episodes of fixed or very rigid exchange rates: the Eurozone before and after the introduction of the Euro, and

  15. Efficiency in Assessment: Can Trained Student Interns Rate Essays as Well as Faculty Members?

    Science.gov (United States)

    Cole, Tracy L.; Cochran, Loretta F.; Troboy, L. Kim; Roach, David W.

    2012-01-01

    What are the most efficient and effective methods in measuring outcomes for assurance of learning in higher education? This study examines the merits of outsourcing part of the assessment workload by comparing ratings completed by trained student interns to ratings completed by faculty. Faculty evaluation of students' written work samples provides…

  16. Experimental and Computational Studies of Heat Transfer in Complex Internal Flows.

    Science.gov (United States)

    1981-01-01

    space having cross-sectional dimensions of 21.6 x 21.6 cm (8.5 x 8.5 in.). Into this space was poured silica aerogel powder insulation whose thermal...types of insulation (silica aerogel and styrofoam) and the surround- ing wooden containment structure. A total of 1600 grid points were used to resolve...Young, G., and Iverson, H. W., "An Investigation of Aircraft Heaters XXVII--Distribution of Heat Transfer Rate in the Entrance Section of a Circular

  17. The potential influence of multiple scattering on longwave flux and heating rate simulations with clouds

    Science.gov (United States)

    Kuo, C. P.; Yang, P.; Huang, X.; Feldman, D.; Flanner, M.; Kuo, C.; Mlawer, E. J.

    2017-12-01

    Clouds, which cover approximately 67% of the globe, serve as one of the major modulators in adjusting radiative energy on the Earth. Since rigorous radiative transfer computations including multiple scattering are costly, only absorption is considered in the longwave spectral bands in the radiation sub-models of the general circulation models (GCMs). Quantification of the effect of ignoring longwave scattering for flux and heating rate simulations is performed by using the GCM version of the Longwave Rapid Radiative Transfer Model (RRTMG_LW) with an implementation with the 16-stream Discrete Ordinates Radiative Transfer (DISORT) Program for a Multi-Layered Plane-Parallel Medium in conjunction with the 2010 CCCM products that merge satellite observations from the Cloud-Aerosol Lidar and Infrared Pathfinder Satellite Observation (CALIPSO), the CloudSat, the Clouds and the Earth's Radiant Energy System (CERES) and the Moderate Resolution Imaging Spectrometer (MODIS). One-year global simulations show that neglecting longwave scattering overestimates upward flux at the top of the atmosphere (TOA) and underestimates downward flux at the surface by approximately 2.63 and 1.15 W/m2, respectively. Furthermore, when longwave scattering is included in the simulations, the tropopause is cooled by approximately 0.018 K/day and the surface is heated by approximately 0.028 K/day. As a result, the radiative effects of ignoring longwave scattering and doubling CO2 are comparable in magnitude.

  18. Gamma ray heating rates due to chromium isotopes in stellar core during late stages of high mass stars (>10M⊙

    Directory of Open Access Journals (Sweden)

    Nabi Jameel-Un

    2017-01-01

    Full Text Available Gamma ray heating rates are thought to play a crucial role during the pre-supernova stage of high mass stars. Gamma ray heating rates, due to β±-decay and electron (positron capture on chromium isotopes, are calculated using proton-neutron quasiparticle random phase approximation theory. The electron capture significantly affects the lepton fraction (Ye and accelerates the core contraction. The gamma rays emitted as a result of weak processes heat the core and tend to hinder the cooling and contraction due to electron capture and neutrino emission. The emitted gamma rays tend to produce enormous entropy and set the convection to play its role at this stage. The gamma heating rates, on 50-60Cr, are calculated for the density range 10 < ρ (g.cm-3 < 1011 and temperature range 107 < T (K < 3.0×1010.

  19. Influence of composition and rate heating on formation of black core in bodies obtained with red ceramic

    International Nuclear Information System (INIS)

    Santana, L.N.L.; Goncalves, W.P.; Silva, B.J. da; Macedo, R.S.; Santos, R.C.; Lisboa, D.

    2011-01-01

    In the heating of pieces of red pottery can the defect known as black core, this may deteriorate the technical and aesthetic characteristics of the final product. This study evaluated the influence of chemical composition and heating rate on the formation of black core in bodies red ceramic. The masses were treated and samples were extruded, dried, sintered at 900 °C, with heating rates of 5, 10, 15, 20 and 30 °C / min. and determined the following properties: water absorption, linear shrinkage and flexural strength. The pieces made with the mass containing lower content of iron oxide showed better resistance to bending when subjected to rapid heating. The presence of the black core was identified through visual analysis of the pieces after the break, being more apparent in parts subject to rates above 5 °C / min. (author)

  20. Development of a water boil-off spent-fuel calorimeter system. [To measure decay heat generation rate

    Energy Technology Data Exchange (ETDEWEB)

    Creer, J.M.; Shupe, J.W. Jr.

    1981-05-01

    A calorimeter system was developed to measure decay heat generation rates of unmodified spent fuel assemblies from commercial nuclear reactors. The system was designed, fabricated, and successfully tested using the following specifications: capacity of one BWR or PWR spent fuel assembly; decay heat generation range 0.1 to 2.5 kW; measurement time of < 12 h; and an accuracy of +-10% or better. The system was acceptance tested using a dc reference heater to simulate spent fuel assembly heat generation rates. Results of these tests indicated that the system could be used to measure heat generation rates between 0.5 and 2.5 kW within +- 5%. Measurements of heat generation rates of approx. 0.1 kW were obtained within +- 15%. The calorimeter system has the potential to permit measurements of heat generation rates of spent fuel assemblies and other devices in the 12- to 14-kW range. Results of calorimetry of a Turkey Point spent fuel assembly indicated that the assembly was generating approx. 1.55 kW.

  1. Effects of heat stress on production, somatic cell score and conception rate in Holsteins.

    Science.gov (United States)

    Hagiya, Koichi; Hayasaka, Kiyoshi; Yamazaki, Takeshi; Shirai, Tatsuo; Osawa, Takefumi; Terawaki, Yoshinori; Nagamine, Yoshitaka; Masuda, Yutaka; Suzuki, Mitsuyoshi

    2017-01-01

    We examined the effects of heat stress (HS) on production traits, somatic cell score (SCS) and conception rate at first insemination (CR) in Holsteins in Japan. We used a total of 228 242 records of milk, fat and protein yields, and SCS for the first three lactations, as well as of CR in heifers and in first- and second-lactation cows that had calved for the first time between 2000 and 2012. Records from 47 prefectural weather stations throughout Japan were used to calculate the temperature-humidity index (THI); areas were categorized into three regional groups: no HS (THI cows, CR was affected by the interaction between HS group and insemination month: with summer and early autumn insemination, there was a reduction in CR, and it was much larger in the mild- and moderate-HS groups than in the no-HS group. © 2016 Japanese Society of Animal Science.

  2. Skin blood flow and local temperature independently modify sweat rate during passive heat stress in humans

    OpenAIRE

    Wingo, Jonathan E.; Low, David A.; Keller, David M.; Brothers, R. Matthew; Shibasaki, Manabu; Crandall, Craig G.

    2010-01-01

    Sweat rate (SR) is reduced in locally cooled skin, which may result from decreased temperature and/or parallel reductions in skin blood flow. The purpose of this study was to test the hypotheses that decreased skin blood flow and decreased local temperature each independently attenuate sweating. In protocols I and II, eight subjects rested supine while wearing a water-perfused suit for the control of whole body skin and internal temperatures. While 34°C water perfused the suit, four microdial...

  3. Exchange rate pass-through and the role of international distribution channels

    OpenAIRE

    Desiraju, Ramarao; Shrikhande, Milind

    1996-01-01

    Manufacturers selling in foreign markets often do not completely pass on the effects of fluctuations in exchange rates to the prices of their products. Our paper addresses this puzzle and studies the effects of the international distribution channel on exchange rate pass-through. We develop an exchange rate pass-through model that takes into account the role of an intermediary between a domestic manufacturer and its consumers in a foreign market. We find that the magnitude of the pass-through...

  4. A study on alkaline heat treated Mg-Ca alloy for the control of the biocorrosion rate.

    Science.gov (United States)

    Gu, X N; Zheng, W; Cheng, Y; Zheng, Y F

    2009-09-01

    To reduce the biocorrosion rate by surface modification, Mg-Ca alloy (1.4wt.% Ca content) was soaked in three alkaline solutions (Na(2)HPO(4), Na(2)CO(3) and NaHCO(3)) for 24h, respectively, and subsequently heat treated at 773K for 12h. Scanning electron microscopy and energy-dispersive spectroscopy results revealed that magnesium oxide layers with the thickness of about 13, 9 and 26microm were formed on the surfaces of Mg-Ca alloy after the above different alkaline heat treatments. Atomic force microscopy showed that the surfaces of Mg-Ca alloy samples became rough after three alkaline heat treatments. The in vitro corrosion tests in simulated body fluid indicated that the corrosion rates of Mg-Ca alloy were effectively decreased after alkaline heat treatments, with the following sequence: NaHCO(3) heatedheatedheated. The cytotoxicity evaluation revealed that none of the alkaline heat treated Mg-Ca alloy samples induced toxicity to L-929 cells during 7days culture.

  5. Rate of Homologous Desensitization and Internalization of the GLP-1 Receptor.

    Science.gov (United States)

    Shaaban, Ghina; Oriowo, Mabayoje; Al-Sabah, Suleiman

    2016-12-26

    The glucagon-like peptide-1 receptor (GLP-1R) is an important target in the treatment of type 2 diabetes mellitus. The aim of this study was to compare the rate of agonist stimulated desensitization and internalization of GLP-1R. To this end, an N-terminally myc-tagged GLP-1R was stably expressed in HEK-293 cells. Homologous desensitization was assessed by measuring the cAMP response to agonist stimulation following pre-incubation with agonist for up to 120 min. Receptor internalization was monitored using an indirect ELISA-based method and confocal microscopy. Pre-incubation with GLP-1 resulted in a time-dependent loss of response to a second stimulation. Washing cells following pre-incubation failed to bring cAMP levels back to basal. Taking this into account, two desensitization rates were calculated: "apparent" (t 1/2 = 19.27 min) and "net" (t 1/2 = 2.99 min). Incubation of cells with GLP-1 also resulted in a time-dependent loss of receptor cell surface expression (t 1/2 = 2.05 min). Rapid agonist-stimulated internalization of GLP-1R was confirmed using confocal microscopy. Stimulation of GLP-1R with GLP-1 results in rapid desensitization and internalization of the receptor. Interestingly, the rate of "net" desensitization closely matches the rate of internalization. Our results suggest that agonist-bound GLP-1R continues to generate cAMP after it has been internalized.

  6. Bounds of thermal stability of infinite cylindrical structures with non-uniform internal heat generation

    International Nuclear Information System (INIS)

    Gadalla, M.A.

    1992-01-01

    This paper presents an overview analyses of the thermal instability or thermal viability of infinite cylindrical structures with non-linear and non-uniform internal heat generation. The structure may be subjected to different and combined boundary conditions. An analytical solution is obtained for the generalized problem in spite of the non-linearity and the non-homogeneity of the source term. Four case studies with different boundary conditions are presented. The analyses show that the critical parameter for thermal stability may be though of as an altitude of surface below which the cylindrical structure will be thermally stable and performance worthy. The results also show that the bounds of thermal stability of a cylindrical structure system (solid or hollow) is eminently determined by the boundary conditions to which the system is subjected and can significantly alter the life-span of the structure

  7. Book of abstracts: International Conference on Smart Energy Systems and 4th Generation District Heating

    DEFF Research Database (Denmark)

    , which takes a sole focus on the electricity sector, the smart energy systems approach includes the entire energy system in its identification of suitable energy infrastructure designs and operation strategies. Focusing solely on the smart electricity grid often leads to the definition of transmission......It is a great pleasure to welcome you to the first International Conference on Smart Energy Systems and 4th Generation District Heating at Aalborg University, Copenhagen Campus on 25-26 August 2015. The conference is organised by the 4DH Strategic Research Centre in collaboration with Aalborg...... University and offers more than 70 presentations in 3 parallel sessions with more than 180 participants from 25 countries around the world. The aim is to present and discuss scientific findings and industrial experiences related to the development of Smart Energy Systems and future 4th Generation District...

  8. Heat and momentum transport of ion internal transport barrier plasmas on Large Helical Device

    International Nuclear Information System (INIS)

    Nagaoka, K.; Ida, K.; Yoshinuma, M.

    2010-11-01

    The peaked ion-temperature profile with steep gradient so called ion internal transport barrier (ion ITB) was formed in the neutral beam heated plasmas on the Large Helical Device (LHD) and the high-ion-temperature regime of helical plasmas has been significantly extended. The ion thermal diffusivity in the ion ITB plasma decreases down to the neoclassical transport level. The heavy ion beam probe (HIBP) observed the smooth potential profile with negative radial electric field (ion root) in the core region where the ion thermal diffusivity decreases significantly. The large toroidal rotation was also observed in the ion ITB core and the transport of toroidal momentum was analyzed qualitatively. The decrease of momentum diffusivity with ion temperature increase was observed in the ion ITB core. The toroidal rotation driven by ion temperature gradient so called intrinsic rotation is also identified. (author)

  9. International patent analysis of water source heat pump based on orbit database

    Science.gov (United States)

    Li, Na

    2018-02-01

    Using orbit database, this paper analysed the international patents of water source heat pump (WSHP) industry with patent analysis methods such as analysis of publication tendency, geographical distribution, technology leaders and top assignees. It is found that the beginning of the 21st century is a period of rapid growth of the patent application of WSHP. Germany and the United States had done researches and development of WSHP in an early time, but now Japan and China have become important countries of patent applications. China has been developing faster and faster in recent years, but the patents are concentrated in universities and urgent to be transferred. Through an objective analysis, this paper aims to provide appropriate decision references for the development of domestic WSHP industry.

  10. Efficiencies of subcritical and transcritical CO2 inverse cycles with and without an internal heat exchanger

    International Nuclear Information System (INIS)

    Zhang, F.Z.; Jiang, P.X.; Lin, Y.S.; Zhang, Y.W.

    2011-01-01

    An internal heat exchanger (IHX) is often used to improve the coefficient of performance (COP) of CO 2 inverse cycles. This paper presents a detailed analysis of the IHX's effect in CO 2 inverse cycles and finds suitable operating conditions for the IHX from a thermodynamic performance point of view. The results indicate that the COP is slightly reduced by an IHX in a CO 2 subcritical inverse cycle, so an IHX is not justified. However, for transcritical CO 2 inverse cycles, the compressor discharge pressures and CO 2 gas cooler outlet temperatures both have significant impacts on system performance. The analysis results for transcritical CO 2 inverse cycles show that a transition discharge pressure and a transition CO 2 gas cooler outlet temperature are objective existence above which the IHX improves the cycle performance. - Research highlights: → Find suitable operating conditions for the IHX. → Above transition CO2 gas cooler outlet temperature IHX improves cycle performance. → The IHX is not very useful for optimized space heating and refrigerating cycles.

  11. Exhaust gas heat recovery through secondary expansion cylinder and water injection in an internal combustion engine

    Directory of Open Access Journals (Sweden)

    Nassiri Toosi Ali

    2017-01-01

    Full Text Available To enhance thermal efficiency and increase performance of an internal combustion engine, a novel concept of coupling a conventional engine with a secondary 4-stroke cylinder and direct water injection process is proposed. The burned gases after working in a traditional 4-stroke combustion cylinder are transferred to a secondary cylinder and expanded even more. After re-compression of the exhaust gases, pre-heated water is injected at top dead center. The evaporation of injected water not only recovers heat from exhaust gases, but also increases the mass of working gas inside the cylinder, therefore improves the overall thermal efficiency. A 0-D/1-D model is used to numerically simulate the idea. The simulations outputs showed that the bottoming cycle will be more efficient at higher engines speeds, specifically in a supercharged/turbocharged engine, which have higher exhaust gas pressure that can reproduce more positive work. In the modeled supercharged engine, results showed that brake thermal efficiency can be improved by about 17%, and brake power by about 17.4%.

  12. Internal transport barrier and β limit in ohmically heated plasma in TUMAN-3M

    International Nuclear Information System (INIS)

    Andreiko, M.V.; Askinazi, L.G.; Golant, V.E.

    2001-01-01

    An Internal Transport Barrier (ITB) was found in ohmically heated plasma in TUMAN-3M (R 0 =53 cm, a l =22 cm - circular limiter configuration, B t ≤0.7T, I p ≤175 kA, ≤6.0·10 19 m -3 ). The barrier reveals itself as a formation of a steep gradient on electron temperature and density radial profiles. The regions with reduced diffusion and electron thermal diffusivity are in between r=0.5a and r=0.7a. The ITB appears more frequently in the shots with higher plasma current. At lower currents (I p N limit in the ohmically heated plasma are presented. Stored energy was measured using diamagnetic loops and compared with W calculated from kinetic data obtained by Thomson scattering and microwave interferometry. Measurements of the stored energy and of the β were performed in the ohmic H-mode before and after boronization and in the scenario with the fast Current Ramp-Down in the ohmic H-mode. Maximum value of β T of 2.0 % and β N of 2 were achieved. The β N limit achieved is 'soft' (nondisruptive) limit. The stored energy slowly decays after the Current Ramp-Down. No correlation was found between beta restriction and MHD phenomena. (author)

  13. Internal transport barrier and β limit in ohmically heated plasma in TUMAN-3M

    International Nuclear Information System (INIS)

    Andreiko, M.V.; Askinazi, L.G.; Golant, V.E.

    1999-01-01

    An Internal Transport Barrier (ITB) was found in ohmically heated plasma in TUMAN-3M (R 0 = 53 cm, a l = 22 cm - circular limiter configuration, B t ≤ 0.7 T, I p ≤ 175 kA, ≤ 6.0·10 19 m -3 ). The barrier reveals itself as a formation of a steep gradient on electron temperature and density radial profiles. The regions with reduced diffusion and electron thermal diffusivity are in between r = 0.5a and r = 0.7a. The ITB appears more frequently in the shots with higher plasma current. At lower currents (I p N limit in the ohmically heated plasma are presented. Stored energy was measured using diamagnetic loops and compared with W calculated from kinetic data obtained by Thomson scattering and microwave interferometry. Measurements of the stored energy and of the β were performed in the ohmic H-mode before and after boronization and in the scenario with the fast Current Ramp-Down in the ohmic H-mode. Maximum value of β T of 2.0% and β N of 2 were achieved. The β N limit achieved is 'soft' (non-disruptive) limit. The stored energy slowly decays after the Current Ramp-Down. No correlation was found between beta restriction and MHD phenomena. (author)

  14. Brayton cycle for internal combustion engine exhaust gas waste heat recovery

    Directory of Open Access Journals (Sweden)

    J Galindo

    2015-06-01

    Full Text Available An average passenger car engine effectively uses about one-third of the fuel combustion energy, while the two-thirds are wasted through exhaust gases and engine cooling. It is of great interest to automotive industry to recover some of this wasted energy, thus increasing the engine efficiency and lowering fuel consumption and contamination. Waste heat recovery for internal combustion engine exhaust gases using Brayton cycle machine was investigated. The principle problems of application of such a system in a passenger car were considered: compressor and expander machine selection, machine size for packaging under the hood, efficiency of the cycle, and improvement of engine efficiency. Important parameters of machines design have been determined and analyzed. An average 2-L turbocharged gasoline engine’s New European Driving Cycle points were taken as inlet points for waste heat recovery system. It is theoretically estimated that the recuperated power of 1515 W can be achieved along with 5.7% improvement in engine efficiency, at the point where engine power is 26550 W.

  15. Tick resistance and heat tolerance characteristics in cattle. III. Sweating rate

    Directory of Open Access Journals (Sweden)

    Cecília José Veríssimo

    2012-12-01

    Full Text Available Cattle in a sustainable tropical livestock should be heat tolerant and resistant to ticks. The relationship between Rhipicephalus (Boophilus microplus infestation and sweating rate, an important heat tolerance characteristic, was studied in six Nellore and four Holstein steers of seven-month-old. They were artificial infested (a.i. with 10,000 (Holstein and 20,000 (Nellore larvae in 16/Apr/2011. In days 20, 23 and 24 after the infestation, the 10 bigger females ticks found in whole animal were weighed and put in a chamber (27 oC and 80% RH, weighing the egg mass of each female tick fourteen days after. The sweating rate (SRskin, measured by Scheleger and Turner, 1963, method, in a shaved area of shoulder skin was evaluated in 14/Apr (2 days before the a.i. and in 05/May (19 days after a.i.. In 14/Apr the Scheleger and Turner, 1963, method was done on the coat not shaved (SRcoat. The sweating rate was measured in the afternoon (from 2 P.M., after 30 minutes of direct sunlight, on April. On May, the animals remained 60 minutes in direct sunlight because this day was colder. The experimental design was a non-probability sample restricted to the 10 available animals. Data from the steers’ sweating rate were analyzed using the General linear models of the SPSS® statistical package (version 12.0 using SRskin as dependent variable and breed and sampling date as independent variables. For SRcoat breed was the independent variable. Nellore, a tropical cattle breed, had higher SRskin (1,000.82 ± 64.59 g m-2 h-1, P< 0.001 than Holstein (620.45 ± 79.10 g m-2 h-1. SRskin was higher on May (1,187.33 ± 71.49 g m-2 h-1, P< 0.001 than on April (433.93 ± 71.49 g m-2 h-1. The correlation between the two different measurements of SR was positive and significant (r= 0,545, P<0,01, Pearson correlation. But in SRcoat the breed effect disappeared because the Holstein SRcoat increased (Holstein: 884.95 ± 472.12 g m-2 h-1 and Nellore: 1,060.72 ± 318.21 g m-2 h-1

  16. The International Heat Stress Genotype Experiment for modeling wheat response to heat: field experiments and AgMIP-Wheat multi-model simulations

    DEFF Research Database (Denmark)

    Martre, Pierre; Reynolds, Matthew; Asseng, Senthold

    2017-01-01

    The data set contains a portion of the International Heat Stress Genotype Experiment (IHSGE) data used in the AgMIP-Wheat project to analyze the uncertainty of 30 wheat crop models and quantify the impact of heat on global wheat yield productivity. It includes two spring wheat cultivars grown...... dates. Data include local daily weather data, soil characteristics and initial soil conditions, crop measurements (anthesis and maturity dates, anthesis and final total above ground biomass, final grain yields and yields components), and cultivar information. Simulations include both daily in-season...... and end-of-season results from 30 wheat models....

  17. Textural and rheological properties of Pacific whiting surimi as affected by nano-scaled fish bone and heating rates.

    Science.gov (United States)

    Yin, Tao; Park, Jae W

    2015-08-01

    Textural and rheological properties of Pacific whiting (PW) surimi were investigated at various heating rates with the use of nano-scaled fish bone (NFB) and calcium chloride. Addition of NFB and slow heating improved gel strength significantly. Activity of endogenous transglutaminase (ETGase) from PW surimi was markedly induced by both NFB calcium and calcium chloride, showing an optimal temperature at 30°C. Initial storage modulus increased as NFB calcium concentration increased and the same trend was maintained throughout the temperature sweep. Rheograms with temperature sweep at slow heating rate (1°C/min) exhibited two peaks at ∼ 35°C and ∼ 70°C. However, no peak was observed during temperature sweep from 20 to 90°C at fast heating rate (20°C/min). Protein patterns of surimi gels were affected by both heating rate and NFB calcium concentration. Under slow heating, myosin heavy chain intensity decreased with NFB calcium concentration, indicating formation of ε-(γ-glutamyl) lysine cross-links by ETGase and NFB calcium ion. Copyright © 2015 Elsevier Ltd. All rights reserved.

  18. Enhancement of heat transfer rate with structural modification of double pipe heat exchanger by changing cylindrical form of tubes into conical form

    International Nuclear Information System (INIS)

    Hashemian, Mehran; Jafarmadar, Samad; Nasiri, Javid; Sadighi Dizaji, Hamed

    2017-01-01

    Highlights: • An improved geometry is presented by changing tubes form into conical. • Enhancement of heat transfer rate is investigated. • Frictional characteristics for novel geometry are studied. • For a proper understanding of the subject, the exact physical interpretation is added. • The effect of flow, geometry and thermodynamic parameters is considered. - Abstract: In this paper, cylindrical tubes of a double pipe heat exchanger were changed into the conical tubes as an innovative design which causes improvement of thermal performance of heat exchanger without increment of its weight. Utilization of conical tube instead of cylindrical tube can impress both thermal and frictional characteristics of heat exchanger. Hence, the effect of conical tubes on Nusselt number, friction factor and thermal performance factor are evaluated in present research which was not covered already. Moreover, the effects of hydrodynamic, thermodynamic and geometrical characteristics are analyzed. All said parameters are numerically investigated for nine different combinations of flow direction and conical tubes geometry. The results of simulations of the said configurations are presented to compare the cases from different points of view and determine the most thermally efficient case. The results reveal modified geometry makes 63% increment in Nu number and 54% increment in heat transfer rate at optimum condition.

  19. The Impact of the Applied Exchange Rate Regimes on the Internal Balance of Transition Countries

    Directory of Open Access Journals (Sweden)

    Vujanić Vlado

    2017-12-01

    Full Text Available One of the key goals of the economic policy makers of every country is to achieve internal and external balance. An unavoidable segment of the analysis concerning the achievement of internal and external balance is certainly the influence of the exchange rate regime applied in a country. European transition countries, despite their similar initial problems and final objectives, applied different exchange rate regimes adapted to the economic circumstances and needs of the country. The paper aims to examine and demonstrate the impact of the applied exchange rate regime on the internal balance of the transition countries. The research encompasses 10 representative transition countries, in the period from 2000-2014. The results of the research, from the aspect of internal balance, confirmed the justification of the application of the floating exchange rate regime in more developed, but not in less-developed, European transition countries. The application of floating exchange rate regimes in less-developed transition countries is associated with a considerably higher average inflation rate, which may be explained by the higher import dependence of lessdeveloped countries and by the consequent transfer of depreciation to price growth.

  20. Radionuclide mass inventory, activity, decay heat, and dose rate parametric data for TRIGA spent nuclear fuels

    International Nuclear Information System (INIS)

    Sterbentz, J.W.

    1997-03-01

    Parametric burnup calculations are performed to estimate radionuclide isotopic mass and activity concentrations for four different Training, Research, and Isotope General Atomics (TRIGA) nuclear reactor fuel element types: (1) Aluminum-clad standard, (2) Stainless Steel-clad standard, (3) High-enrichment Fuel Life Improvement Program (FLIP), and (4) Low-enrichment Fuel Life Improvement Program (FLIP-LEU-1). Parametric activity data are tabulated for 145 important radionuclides that can be used to generate gamma-ray emission source terms or provide mass quantity estimates as a function of decay time. Fuel element decay heats and dose rates are also presented parametrically as a function of burnup and decay time. Dose rates are given at the fuel element midplane for contact, 3.0-feet, and 3.0-meter detector locations in air. The data herein are estimates based on specially derived Beginning-of-Life (BOL) neutron cross sections using geometrically-explicit TRIGA reactor core models. The calculated parametric data should represent good estimates relative to actual values, although no experimental data were available for direct comparison and validation. However, because the cross sections were not updated as a function of burnup, the actinide concentrations may deviate from the actual values at the higher burnups

  1. Estimation of internal heat transfer coefficients and detection of rib positions in gas turbine blades from transient surface temperature measurements

    International Nuclear Information System (INIS)

    Heidrich, P; Wolfersdorf, J v; Schmidt, S; Schnieder, M

    2008-01-01

    This paper describes a non-invasive, non-destructive, transient inverse measurement technique that allows one to determine internal heat transfer coefficients and rib positions of real gas turbine blades from outer surface temperature measurements after a sudden flow heating. The determination of internal heat transfer coefficients is important during the design process to adjust local heat transfer to spatial thermal load. The detection of rib positions is important during production to fulfill design and quality requirements. For the analysis the one-dimensional transient heat transfer problem inside of the turbine blade's wall was solved. This solution was combined with the Levenberg-Marquardt method to estimate the unknown boundary condition by an inverse technique. The method was tested with artificial data to determine uncertainties with positive results. Then experimental testing with a reference model was carried out. Based on the results, it is concluded that the presented inverse technique could be used to determine internal heat transfer coefficients and to detect rib positions of real turbine blades.

  2. An ideal internally heat integrated batch distillation with a jacketed still with application to a reactive system

    International Nuclear Information System (INIS)

    Jana, Amiya K.; Maiti, Debadrita

    2013-01-01

    Batch distillation is an irreversible process and consumes many times the theoretical minimum energy requirement. The present work focuses on the development of an internally heat integrated batch distillation with a jacketed still (IHIBDJS) aiming to reduce the degree of irreversibility towards zero. The IHIBDJS scheme consists of a rectifying tower equipped with an overhead condenser and a still pot or reboiler that surrounds the tower concentrically. For improving the energy efficiency by the reduction of external energy input, the rectifier is operated at an elevated pressure so that a thermal driving force should exist between the rectifying tower and the concentric still. For this purpose, an isentropic compression system is mounted in the reboiled vapor line. Aiming to reduce further the degree of process irreversibility, we propose an additional thermal arrangement into the IHIBDJS configuration that couples the overhead vapor with the reboiler liquid, thereby reducing further the external heat consumption. It is investigated for a reactive batch distillation column that the effective use of internal heat sources would make the heat integrated column an independent scheme of external heat source. - Highlights: • An internal heat integration approach is developed for batch distillation. • Further intensification is made by thermally coupling top vapor with still liquid. • A reactive system is used to illustrate the proposed scheme

  3. Influence of radiant energy exchange on the determination of convective heat transfer rates to Orbiter leeside surfaces during entry

    Science.gov (United States)

    Throckmorton, D. A.

    1982-01-01

    Temperatures measured at the aerodynamic surface of the Orbiter's thermal protection system (TPS), and calorimeter measurements, are used to determine heating rates to the TPS surface during atmospheric entry. On the Orbiter leeside, where convective heating rates are low, it is possible that a significant portion of the total energy input may result from solar radiation, and for the wing, cross radiation from the hot (relatively) Orbiter fuselage. In order to account for the potential impact of these sources, values of solar- and cross-radiation heat transfer are computed, based upon vehicle trajectory and attitude information and measured surface temperatures. Leeside heat-transfer data from the STS-2 mission are presented, and the significance of solar radiation and fuselage-to-wing cross-radiation contributions to total energy input to Orbiter leeside surfaces is assessed.

  4. Effect of heating rate on the mechanical properties and microstructure of Ti(C,N)-based cermets

    Energy Technology Data Exchange (ETDEWEB)

    Xu, Qingzhong; Ai, Xing, E-mail: aixingsdu@163.com; Zhao, Jun; Zhang, Hongshan; Qin, Wenzhen; Gong, Feng

    2015-03-25

    An appropriate heating rate in the sintering process is crucial to obtain the Ti(C,N)-based cermets with superior properties. In this paper, Ti(C,N)-based cermets were sintered to investigate the influence of heating rate on the mechanical properties and microstructure of the cermet materials. The transverse rupture strength (TRS), Vickers hardness (HV) and fracture toughness (K{sub IC}) were tested. The microstructure, indention crack, fracture morphology and phase composition of the cermets were also studied by scanning electron microscope (SEM) with energy dispersive spectroscopy (EDS) and X-ray diffraction (XRD). The results reveal that the heating rate has a great influence on the mechanical properties and microstructure of Ti(C,N)-based cermets. The cermets sintered at the heating rate of 3 °C/min between 1300 °C and 1430 °C have the optimum comprehensive mechanical properties with a transverse rupture strength of 1605±107 MPa, a hardness of 12.02±0.25 GPa and a fracture toughness of 10.73±0.40 MPa m{sup 1/2}. The heating rate can affect the reaction among the constituents of Ti(C,N)-based cermets and then influence the elements distribution in the core–rim microstructures and the lattice parameter of Ti(C,N) phase. When the heating rate is between 2 °C/min and 5 °C/min, the lower the heating rate is, the coarser the Ti(C,N) grains become. A higher heating rate is detrimental to the formation of core–rim microstructures, and a lower heating rate can result in grain coarsening and inhomogeneous microstructure. The observation of indention cracks and fracture surfaces show that the intergranular cracks and intergranular fractures mainly occur in the cermets with larger binder mean free path and medium grains. While the cleavage fractures appear more in the cermets with grain coarsening, and the transgranular fractures exist more in the cermets with non-fully developed fine grains.

  5. Time and spatial heat transfer performance around an isothermally heated sphere placed in a uniform, downwardly directed flow (in relation to the enhancement of latent heat storage rate in a spherical capsule)

    International Nuclear Information System (INIS)

    Koizumi, H.

    2004-01-01

    The aim of this study is to reveal the temporal and spatial heat transfer performance of an isothermally heated sphere placed in a uniform, downwardly directed flow using a micro-foil heat flow sensor (HFS). A HFS, whose response time is about 0.02 s, was pasted on the surface of a heated copper sphere. Experiments were carried out using air with a Grashof number of 3.3 x 10 5 and with several Reynolds numbers (Re) up to 1800. Three flow patterns appeared: a chaotic flow at Re<240; a two-dimensional steady separated flow at 240 ≤ Re<500, and a three-dimensional unsteady separated flow at Re ≥ 500. In addition, the instantaneous and time-averaged heat transfer performance around the sphere in each of the three regions was clarified. Next, enhancement of the latent heat storage rate of a solid phase change material (PCM) in a spherical capsule was performed. The flow around the spherical capsule, in which the solid PCM was filled and placed in a heated, upwardly directed flow, is the approximate adverse flow phenomenon around the heated sphere which was placed in a downwardly directed flow. In other words, the buoyant flow and the forced flow are in the opposite directions in these two cases. Tests of latent heat storage were run for two Reynolds numbers which represented different flow characteristics in the heat transfer experiments, Re=150 and 1800. Furthermore, copper plates were inserted into the solid PCM, of which thermal conductivity was considerably low, to enhance the latent heat storage rate for the two Reynolds number flows

  6. An artificial intelligence heat rate/NOx optimization system for Ontario Hydro`s Lambton Generating Station

    Energy Technology Data Exchange (ETDEWEB)

    Luk, J.; Bachalo, K.; Henrikson, J. [Ontario Hydro, Toronto, ON (Canada); Roland, W.; Booth, R.C.; Parikh, N.; Radl, B. [Pegasus Technologies Ltd., Painesville, OH (United States)

    1998-12-01

    The utilization of artificial Intelligence (AI)-based software programs to optimize power plant operations by simultaneously improving heat rate performance and reducing NOx emissions was discussed. While many AI programs were initially used for demonstration purposes, they are now available for commercial use due to their promising results. In 1996, the Fossil Business Unit of Ontario Hydro initiated a study to evaluate AI technology as a tool for optimizing heat rate and NOx reduction in coal fired stations. Tests were conducted at Units 3 and 4 of the Lambton Generation Station, located just south of Sarnia, Ontario. The tests were conducted to examine three desirable options: (1) achieve at least 0.5 per cent improvement in heat rate concurrently with a NOx reduction of at least 5 per cent, (2) optimize on `heat rate` only with minimum improvement of 2 per cent, and optimize `minimal NOx` only with reduction target of 20 per cent or more, and (3) reach a collaborative agreement with a supplier to further explore and develop AI optimization applications for other advanced and more complex plant processes. Results indicated that NOx reduction and heat rate improvement are not contradictory goals. 15 refs., 1 fig.

  7. Heat and mass transfer analysis for paraffin/nitrous oxide burning rate in hybrid propulsion

    Science.gov (United States)

    Ben-Basat (Sisi), Shani; Gany, Alon

    2016-03-01

    This research presents a physical-mathematical model for the combustion of liquefying fuels in hybrid combustors, accounting for blowing effect on the heat transfer. A particular attention is given to a paraffin/nitrous oxide hybrid system. The use of a paraffin fuel in hybrid propulsion has been considered because of its much higher regression rate enabling significantly higher thrust compared to that of common polymeric fuels. The model predicts the overall regression rate (melting rate) of the fuel and the different mechanisms involved, including evaporation, entrainment of droplets of molten material, and mass loss due to melt flow on the condensed fuel surface. Prediction of the thickness and velocity of the liquid (melt) layer formed at the surface during combustion was done as well. Applying the model for an oxidizer mass flux of 45 kg/(s m2) as an example representing experimental range, it was found that 21% of the molten liquid undergoes evaporation, 30% enters the gas flow by the entrainment mechanism, and 49% reaches the end of the combustion chamber as a flowing liquid layer. When increasing the oxidizer mass flux in the port, the effect of entrainment increases while that of the flowing liquid layer along the surface shows a relatively lower contribution. Yet, the latter is predicted to have a significant contribution to the overall mass loss. In practical applications it may cause reduced combustion efficiency and should be taken into account in the motor design, e.g., by reinforcing the paraffin fuel with different additives. The model predictions have been compared to experimental results revealing good agreement.

  8. Uncertainties in the estimation of specific absorption rate during radiofrequency alternating magnetic field induced non-adiabatic heating of ferrofluids

    Science.gov (United States)

    Lahiri, B. B.; Ranoo, Surojit; Philip, John

    2017-11-01

    Magnetic fluid hyperthermia (MFH) is becoming a viable cancer treatment methodology where the alternating magnetic field induced heating of magnetic fluid is utilized for ablating the cancerous cells or making them more susceptible to the conventional treatments. The heating efficiency in MFH is quantified in terms of specific absorption rate (SAR), which is defined as the heating power generated per unit mass. In majority of the experimental studies, SAR is evaluated from the temperature rise curves, obtained under non-adiabatic experimental conditions, which is prone to various thermodynamic uncertainties. A proper understanding of the experimental uncertainties and its remedies is a prerequisite for obtaining accurate and reproducible SAR. Here, we study the thermodynamic uncertainties associated with peripheral heating, delayed heating, heat loss from the sample and spatial variation in the temperature profile within the sample. Using first order approximations, an adiabatic reconstruction protocol for the measured temperature rise curves is developed for SAR estimation, which is found to be in good agreement with those obtained from the computationally intense slope corrected method. Our experimental findings clearly show that the peripheral and delayed heating are due to radiation heat transfer from the heating coils and slower response time of the sensor, respectively. Our results suggest that the peripheral heating is linearly proportional to the sample area to volume ratio and coil temperature. It is also observed that peripheral heating decreases in presence of a non-magnetic insulating shielding. The delayed heating is found to contribute up to ~25% uncertainties in SAR values. As the SAR values are very sensitive to the initial slope determination method, explicit mention of the range of linear regression analysis is appropriate to reproduce the results. The effect of sample volume to area ratio on linear heat loss rate is systematically studied and the

  9. Uncertainties in the estimation of specific absorption rate during radiofrequency alternating magnetic field induced non-adiabatic heating of ferrofluids

    International Nuclear Information System (INIS)

    Lahiri, B B; Ranoo, Surojit; Philip, John

    2017-01-01

    Magnetic fluid hyperthermia (MFH) is becoming a viable cancer treatment methodology where the alternating magnetic field induced heating of magnetic fluid is utilized for ablating the cancerous cells or making them more susceptible to the conventional treatments. The heating efficiency in MFH is quantified in terms of specific absorption rate (SAR), which is defined as the heating power generated per unit mass. In majority of the experimental studies, SAR is evaluated from the temperature rise curves, obtained under non-adiabatic experimental conditions, which is prone to various thermodynamic uncertainties. A proper understanding of the experimental uncertainties and its remedies is a prerequisite for obtaining accurate and reproducible SAR. Here, we study the thermodynamic uncertainties associated with peripheral heating, delayed heating, heat loss from the sample and spatial variation in the temperature profile within the sample. Using first order approximations, an adiabatic reconstruction protocol for the measured temperature rise curves is developed for SAR estimation, which is found to be in good agreement with those obtained from the computationally intense slope corrected method. Our experimental findings clearly show that the peripheral and delayed heating are due to radiation heat transfer from the heating coils and slower response time of the sensor, respectively. Our results suggest that the peripheral heating is linearly proportional to the sample area to volume ratio and coil temperature. It is also observed that peripheral heating decreases in presence of a non-magnetic insulating shielding. The delayed heating is found to contribute up to ∼25% uncertainties in SAR values. As the SAR values are very sensitive to the initial slope determination method, explicit mention of the range of linear regression analysis is appropriate to reproduce the results. The effect of sample volume to area ratio on linear heat loss rate is systematically studied and

  10. Computation of single- and two-phase heat transfer rates suitable for water-cooled tubes and subchannels

    International Nuclear Information System (INIS)

    Groeneveld, D.C.; Leung, L.K.H.; Cheng, S.C.; Nguyen, C.

    1989-01-01

    A computational method for predicting heat transfer, valid for a wide range of flow conditions (from pool boiling and laminar flow conditions to highly turbulent flow), has been developed. It correctly identifies the heat transfer modes and predicts the heat transfer rates as well as transition points (such as the critical heat flux point) on the boiling curve. The computational heat transfer method consists of a combination of carefully chosen heat transfer equations for each heat transfer mode. Each of these equations has been selected because of their accuracy, wide range of application, and correct asymptotic trends. Using a mechanistically-based heat transfer logic, these equations have been combined in a convenient software package suitable for PC or mainframe application. The computational method has been thoroughly tested against many sets of experimental data. The parametric and asymptotic trends of the prediction method have been examined in detail. Correction factors are proposed for extending the use of individual predictive techniques to various geometric configurations and upstream conditions. (orig.)

  11. Pupil responses and pain ratings to heat stimuli: Reliability and effects of expectations and a conditioning pain stimulus.

    Science.gov (United States)

    Eisenach, James C; Curry, Regina; Aschenbrenner, Carol A; Coghill, Robert C; Houle, Timothy T

    2017-03-01

    The locus coeruleus (LC) signals salience to sensory stimuli and these responses can modulate the experience of pain stimuli. The pupil dilation response (PDR) to noxious stimuli is thought to be a surrogate for LC responses, but PDR response to Peltier-controlled noxious heat stimuli, the most commonly used method in experimental pain research, has not been described. Healthy volunteers were presented with randomly presented heat stimuli of 5 sec duration and provided pain intensity ratings to each stimulus. Pupillometry was performed and a method developed to quantify the PDR relevant to these stimuli. The stimulus response, reliability, and effect of commonly used manipulations on pain experience were explored. A method of artifact removal and adjusting for lag from stimulus initiation to PDR response was developed, resulting in a close correlation between pain intensity rating and PDR across a large range of heat stimuli. A reliable assessment of PDR within an individual was achieved with fewer presentations as heat stimulus intensity increased. The correlation between pain rating and PDR was disrupted when cognitive load is increased by manipulating expectations or presenting a second pain stimulus. The PDR began later after skin heating than electrical stimuli and this is the first examination of the PDR using standard nociceptive testing and manipulations of expectations and competing noxious stimulation. A method is described applying PDR to standard heat nociceptive testing, demonstrating stimulus response, reliability, and disruption by cognitive manipulation. Copyright © 2017 Elsevier B.V. All rights reserved.

  12. Assessment of breathing rate of adult Korean for use in internal dosimetry

    International Nuclear Information System (INIS)

    Kim, J.I.; Lee, Y.J.; Jin, Y.W.; Kim, C.S.; Lee, J.K.

    2003-01-01

    Breathing rate is one of the key factors in evaluating doses due to inhalation of airborne radionuclides. Since the reference values of breathing rate provided by the International Commission on Radiological Protection (ICRP) are based on the physiology of Caucasian, they are not necessarily appropriate for internal dosimetry for Korean. In this study, we assessed breathing rate of Korean by measuring the forced vital capacity (FVC), the forced expiratory volume in second (FEV1) and the minute ventilation(MV). Measurements were made using SP-1 spirometry unit (Schiller AG. 1998) for 1474 adult Koreans whose heights and weights are in the range of one standard deviation from the mean values. The total liters of air breathed for working and resting were evaluated after the ICRP approach. We also considered smoking and ailment in the lungs. The resulting breathing rate appears to be 2.3x10 4 L/day which well agrees with the value given in ICRP 23

  13. Combined Effect of Heating Rate and Microalloying Elements on Recrystallization During Annealing of Dual-Phase Steels

    Science.gov (United States)

    Bellavoine, Marion; Dumont, Myriam; Drillet, Josée; Hébert, Véronique; Maugis, Philippe

    2018-05-01

    Adjusting ferrite recrystallization kinetics during annealing is a way to control the final microstructure and thus the mechanical properties of advanced cold-rolled high-strength steels. Two strategies are commonly used for this purpose: adjusting heating rates and/or adding microalloying elements. The present work investigates the effect of heating rate and microalloying elements Ti, Nb, and Mo on recrystallization kinetics during annealing in various cold-rolled Dual-Phase steel grades. The use of combined experimental and modeling approaches allows a deeper understanding of the separate influence of heating rate and the addition of microalloying elements. The comparative effect of Ti, Nb, and Mo as solute elements and as precipitates on ferrite recrystallization is also clarified. It is shown that solute drag has the largest delaying effect on recrystallization in the present case and that the order of solute drag effectiveness of microalloying elements is Nb > Mo > Ti.

  14. Interest-Rate Volatility in the Baltics: Issues of Measurement and International Contagion

    OpenAIRE

    Scott W. Hegerty

    2015-01-01

    Prior to their entry into the Eurozone, the Baltic countries of Estonia, Latvia, and Lithuania faced a major financial crisis that was brought about by events abroad. This financial risk led to instability in the real economy as well. This study uses monthly data to first model interest-rate volatility as a measure of financial instability before using our preferred volatility measure to test for international spillovers among interest-rate and output fluctuations. Vector Autoregressive (VAR)...

  15. Publication rates of public health theses in international and national peer-review journals in Turkey.

    Science.gov (United States)

    Sipahi, H; Durusoy, R; Ergin, I; Hassoy, H; Davas, A; Karababa, Ao

    2012-01-01

    Thesis is an important part of specialisation and doctorate education and requires intense work. The aim of this study was to investigate the publication rates of Turkish Public Health Doctorate Theses (PHDT) and Public Health Specialization (PHST) theses in international and Turkish national peer-review journals and to analyze the distribution of research areas. List of all theses upto 30 September 2009 were retrieved from theses database of the Council of Higher Education of the Republic of Turkey. The publication rates of these theses were found by searching PubMed, Science Citation Index-Expanded, Turkish Academic Network and Information Center (ULAKBIM) Turkish Medical Database, and Turkish Medline databases for the names of thesis author and mentor. The theses which were published in journals indexed either in PubMed or SCI-E were considered as international publications. Our search yielded a total of 538 theses (243 PHDT, 295 PHST). It was found that the overall publication rate in Turkish national journals was 18%. The overall publication rate in international journals was 11.9%. Overall the most common research area was occupational health. Publication rates of Turkish PHDT and PHST are low. A better understanding of factors affecting this publication rate is important for public health issues where national data is vital for better intervention programs and develop better public health policies.

  16. Relationship between particle and heat transport in JT-60U plasmas with internal transport barrier

    International Nuclear Information System (INIS)

    Takenaga, H.; Higashijima, S.; Oyama, N.

    2003-01-01

    The relationship between particle and heat transport in an internal transport barrier (ITB) has been systematically investigated in reversed shear (RS) and high β p ELMy H-mode plasmas in JT-60U. No helium and carbon accumulation inside the ITB is observed even with ion heat transport reduced to a neoclassical level. On the other hand, the heavy impurity argon is accumulated inside the ITB. The argon density profile estimated from the soft x-ray profile is more peaked, by a factor of 2-4 in the RS plasma and of 1.6 in the high β p mode plasma, than the electron density profile. The helium diffusivity (D He ) and the ion thermal diffusivity (χ i ) are at an anomalous level in the high β p mode plasma, where D He and χ i are higher by a factor of 5-10 than the neoclassical value. In the RS plasma, D He is reduced from the anomalous to the neoclassical level, together with χ i . The carbon and argon density profiles calculated using the transport coefficients reduced to the neoclassical level only in the ITB are more peaked than the measured profiles, even when χ i is reduced to the neoclassical level. Argon exhaust from the inside of the ITB is demonstrated by applying ECH in the high β p mode plasma, where both electron and argon density profiles become flatter. The reduction of the neoclassical inward velocity for argon due to the reduction of density gradient is consistent with the experimental observation. In the RS plasma, the density gradient is not decreased by ECH and argon is not exhausted. These results suggest the importance of density gradient control to suppress heavy impurity accumulation. (author)

  17. Relationship between particle and heat transport in JT-60U plasmas with internal transport barrier

    International Nuclear Information System (INIS)

    Takenaga, Hidenobu; Higashijima, S.; Oyama, N.

    2003-01-01

    The relationship between particle and heat transport in an internal transport barrier (ITB) has been systematically investigated in reversed shear (RS) and high β p ELMy H-mode plasmas in JT-60U. No helium and carbon accumulation inside the ITB is observed even with ion heat transport reduced to a neoclassical level. On the other hand, the heavy impurity argon is accumulated inside the ITB. The argon density profile estimated from the soft x-ray profile is more peaked, by a factor of 2-4 in the RS plasma and of 1.6 in the high β p mode plasma, than the electron density profile. The helium diffusivity (D He ) and the ion thermal diffusivity (χ i ) are at an anomalous level in the high β p mode plasma, where D He and χ i are higher by a factor of 5-10 than the neoclassical value. In the RS plasma, D He is reduced from the anomalous to the neoclassical level, together with χ i . The carbon and argon density profiles calculated using the transport coefficients reduced to the neoclassical level only in the ITB are more peaked than the measured profiles, even when χ i is reduced to the neoclassical level. Argon exhaust from the inside of the ITB is demonstrated by applying ECH in the high β p mode plasma, where both electron and argon density profiles become flatter. The reduction of the neoclassical inward velocity for argon due to the reduction of density gradient is consistent with the experimental observation. In the RS plasma, the density gradient is not decreased by ECH and argon is not exhausted. These results suggest the importance of density control to suppress heavy impurity accumulation. (author)

  18. Some problems in steady-state thermal conductivity with variable heat transfer rate

    International Nuclear Information System (INIS)

    Malov, Yu.I.; Martinson, L.K.; Pavlov, K.B.

    1975-01-01

    Some boundary-value problems of steady heat conductivity with an alternating heat exchange coefficient have been solved for a cylindrical region. The solutions have been performed as expansion in series with respect to eigenfunctions with the coefficients consistent with infinite systems of linear algebraic equations. A reduction method has been substantiated for those systems. The paper presents results of calculation of the temperature distribution inside the infinite cylinder with concrete tasks of heat exchange coefficient variations on the cylinder surface

  19. 76 FR 2930 - International Product Change-Global Expedited Package Services-Non- Published Rates

    Science.gov (United States)

    2011-01-18

    ... POSTAL SERVICE International Product Change--Global Expedited Package Services-- Non- Published... request with the Postal Regulatory Commission to add Global Expedited Package Services-- Non-Published...--Non-Published Rates, to the Competitive Products List, and Notice of Filing (Under Seal) the Enabling...

  20. On the sensitivity of dimensional stability of high density polyethylene on heating rate

    Directory of Open Access Journals (Sweden)

    2007-02-01

    Full Text Available Although high density polyethylene (HDPE is one of the most widely used industrial polymers, its application compared to its potential has been limited because of its low dimensional stability particularly at high temperature. Dilatometry test is considered as a method for examining thermal dimensional stability (TDS of the material. In spite of the importance of simulation of TDS of HDPE during dilatometry test it has not been paid attention by other investigators. Thus the main goal of this research is concentrated on simulation of TDS of HDPE. Also it has been tried to validate the simulation results and practical experiments. For this purpose the standard dilatometry test was done on the HDPE speci­mens. Secant coefficient of linear thermal expansion was computed from the test. Then by considering boundary conditions and material properties, dilatometry test has been simulated at different heating rates and the thermal strain versus temper­ature was calculated. The results showed that the simulation results and practical experiments were very close together.

  1. Shut-down dose rate analyses for the ITER electron cyclotron-heating upper launcher

    Energy Technology Data Exchange (ETDEWEB)

    Weinhorst, Bastian; Serikov, Arkady; Fischer, Ulrich; Lu, Lei [Institute for Neutron Physics and Reactor Technology INR (Germany); Karlsruhe Institute of Technology KIT (Germany); Spaeh, Peter; Strauss, Dirk [Institute for Applied Materials IAM (Germany); Karlsruhe Institute of Technology KIT (Germany)

    2014-10-15

    The electron cyclotron resonance heating upper launcher (ECHUL) is going to be installed in the upper port of the ITER tokamak thermonuclear fusion reactor for plasma mode stabilization (neoclassical tearing modes and the sawtooth instability). The paper reports the latest neutronic modeling and analyses which have been performed for the ITER reference front steering launcher design. It focuses on the port accessibility after reactor shut-down for which dose rate (SDDR) distributions on a fine regular mesh grid were calculated. The results are compared to those obtained for the ITER Dummy Upper Port. The calculations showed that the heterogeneous ECHUL design gives rise to enhanced radiation streaming as compared to the homogenous dummy upper port. Therefore the used launcher geometry was upgraded to a more recent development stage. The inter-comparison shows a significant improvement of the launchers shielding properties but also the necessity to further upgrade the shielding performance. Furthermore, the analysis for the homogenous dummy upper port, which represents optimal shielding inside the launcher, demonstrates that the shielding upgrade also needs to include the launcher's environment.

  2. Enhanced Thermostability of Arabidopsis Rubisco activase improves photosynthesis and growth rates under moderate heat stress.

    Science.gov (United States)

    Kurek, Itzhak; Chang, Thom Kai; Bertain, Sean M; Madrigal, Alfredo; Liu, Lu; Lassner, Michael W; Zhu, Genhai

    2007-10-01

    Plant photosynthesis declines when the temperature exceeds its optimum range. Recent evidence indicates that the reduction in photosynthesis is linked to ribulose-1,5-bis-phosphate carboxylase/oxygenase (Rubisco) deactivation due to the inhibition of Rubisco activase (RCA) under moderately elevated temperatures. To test the hypothesis that thermostable RCA can improve photosynthesis under elevated temperatures, we used gene shuffling technology to generate several Arabidopsis thaliana RCA1 (short isoform) variants exhibiting improved thermostability. Wild-type RCA1 and selected thermostable RCA1 variants were introduced into an Arabidopsis RCA deletion (Deltarca) line. In a long-term growth test at either constant 26 degrees C or daily 4-h 30 degrees C exposure, the transgenic lines with the thermostable RCA1 variants exhibited higher photosynthetic rates, improved development patterns, higher biomass, and increased seed yields compared with the lines expressing wild-type RCA1 and a slight improvement compared with untransformed Arabidopsis plants. These results provide clear evidence that RCA is a major limiting factor in plant photosynthesis under moderately elevated temperatures and a potential target for genetic manipulation to improve crop plants productivity under heat stress conditions.

  3. Stability Analysis and Internal Heating Effect on Oscillatory Convection in a Viscoelastic Fluid Saturated Porous Medium Under Gravity Modulation

    Science.gov (United States)

    Bhadauria, B. S.; Singh, M. K.; Singh, A.; Singh, B. K.; Kiran, P.

    2016-12-01

    In this paper, we investigate the combined effect of internal heating and time periodic gravity modulation in a viscoelastic fluid saturated porous medium by reducing the problem into a complex non-autonomous Ginzgburg-Landau equation. Weak nonlinear stability analysis has been performed by using power series expansion in terms of the amplitude of gravity modulation, which is assumed to be small. The Nusselt number is obtained in terms of the amplitude for oscillatory mode of convection. The influence of viscoelastic parameters on heat transfer has been discussed. Gravity modulation is found to have a destabilizing effect at low frequencies and a stabilizing effect at high frequencies. Finally, it is found that overstability advances the onset of convection, more with internal heating. The conditions for which the complex Ginzgburg-Landau equation undergoes Hopf bifurcation and the amplitude equation undergoes supercritical pitchfork bifurcation are studied.

  4. Stability Analysis and Internal Heating Effect on Oscillatory Convection in a Viscoelastic Fluid Saturated Porous Medium Under Gravity Modulation

    Directory of Open Access Journals (Sweden)

    Bhadauria B.S.

    2016-12-01

    Full Text Available In this paper, we investigate the combined effect of internal heating and time periodic gravity modulation in a viscoelastic fluid saturated porous medium by reducing the problem into a complex non-autonomous Ginzgburg-Landau equation. Weak nonlinear stability analysis has been performed by using power series expansion in terms of the amplitude of gravity modulation, which is assumed to be small. The Nusselt number is obtained in terms of the amplitude for oscillatory mode of convection. The influence of viscoelastic parameters on heat transfer has been discussed. Gravity modulation is found to have a destabilizing effect at low frequencies and a stabilizing effect at high frequencies. Finally, it is found that overstability advances the onset of convection, more with internal heating. The conditions for which the complex Ginzgburg-Landau equation undergoes Hopf bifurcation and the amplitude equation undergoes supercritical pitchfork bifurcation are studied.

  5. Monte Carlo study of internal energy and specific heat of a nano-graphene bilayer in a longitudinal magnetic field

    Energy Technology Data Exchange (ETDEWEB)

    Luo, Xiao-hong; Wang, Wei, E-mail: ww9803@126.com; Chen, Dong-dong; Xu, Si-yuan

    2016-06-15

    The thermodynamic properties of a nano-graphene bilayer, consisting of the upper layer A of spin-3/2 with antiferromagnetic intralayer exchange coupling and the bottom layer B of spin-5/2 with ferromagnetic intralayer exchange coupling, have been studied by the use of Monte Carlo simulation. We find a number of characteristic phenomena. The effects of the exchange coupling, the single-ion anisotropy and the longitudinal magnetic field on the internal energy, the specific heat and the blocking temperature of the mixed-spin bilayer system have been investigated in detail. The internal energy and the specific heat profiles are clarified. In particular, we have found that the specific heat curve may show two peaks phenomenon for appropriate values of the system parameters.

  6. Curing of a Bisphenol-E Based Cyanate Ester using Magnetic Nanoparticles as an Internal Heat Source through Induction Heating

    Science.gov (United States)

    2013-11-01

    reactions forming high-temperature thermosetting polymers and for innovative ways to process such polymers. 15. SUBJECT TERMS 16. SECURITY...reaction should allow for other reactions forming high-temperature thermosetting polymers and for innovative ways to process such polymers...generated by the particles in a polymer,18 1 µm nickel alloy (Nitinol) used to compare polymerizations with conventional or induction heating,19 or a

  7. Combining Environmental and Spatial Discount Rates for Valuation of Assets According to International Financial Reporting Standards

    Directory of Open Access Journals (Sweden)

    Jaunzeme Justine Sophia

    2016-06-01

    Full Text Available Application of discount rate in finance and accounting is founded on the concept of time value of money. Discounted cash flow model is widely used for asset valuation under the International Financial Reporting Standards (in abbreviation, IFRS. The discount rate applied in valuation models normally is the best rate of return that investors would earn alternative investments. With emergence of ecological economics as a separate branch of economics, the concept of ecological (or in other words, environmental discount rate has been elaborated. Muller (2013 in his paper ‘The Discounting Confusion: an Ecological Economics Perspective’, argues that traditional discounting can undermine long-term sustainability of the economy. In his work, Frank G. Muller considered adjusting the traditional discount rate in order to arrive at an environmental discount rate, which would help to ensure the sustainability of the economy. Hannon (2001 and Perrings (2001 in their paper ‘An Introduction to Spatial Discounting’ consider another variation of the discount rate - spatial discount rate. Spatial discount rate represents the rate at which the diffusion of environmental effects of economic activities is discounted over space. By February 2016, neither the application of environmental nor spatial discount rates under IFRS has been considered. The purpose of this paper is to analyse the implications that environmental and spatial discounting would have for the application of discounted cash flow model according to IFRS. The research methods applied are methods of economic analysis and synthesis.

  8. Effects of heating method and conditions on the evaporation rate and quality attributes of black mulberry (Morus nigra) juice concentrate.

    Science.gov (United States)

    Fazaeli, Mahboubeh; Hojjatpanah, Ghazale; Emam-Djomeh, Zahra

    2013-02-01

    Black mulberry juice was concentrated by different heating methods, including conventional heating and microwave heating, at different operational pressures (7.3, 38.5 and 100 kPa). The effects of each method on evaporation rate, quality attributes of concentrated juice were investigated. The final juice concentration of 42° Brix was achieved in 140, 120, and 95 min at 100, 38.5, and 7.3 kPa respectively by using a rotary evaporator. Applying microwave energy decreased required times to 115, 95, and 60 min. The changes in color, anthocyanin content during the concentration processes were investigated. Hunter parameters (L, a, and b) were measured to estimate the intensity of color loss. All Hunter color parameters decreased with time. Results showed that the degradation of color and consequently anthocyanins, was more pronounced in rotary evaporation compared to microwave heating method.

  9. Cross-correlations between RMB exchange rate and international commodity markets

    Science.gov (United States)

    Lu, Xinsheng; Li, Jianfeng; Zhou, Ying; Qian, Yubo

    2017-11-01

    This paper employs multifractal detrended analysis (MF-DFA) and multifractal detrended cross-correlation analysis (MF-DCCA) to study cross-correlation behaviors between China's RMB exchange rate market and four international commodity markets, using a comprehensive set of data covering the period from 22 July 2005 to 15 March 2016. Our empirical results from MF-DFA indicate that the RMB exchange rate is the most inefficient among the 4 selected markets. The results from quantitative analysis have testified the existence of cross-correlations and the result from MF-DCCA have further confirmed a strong multifractal behavior between RMB exchange rate and international commodity markets. We also demonstrate that the recent financial crisis has significant impact on the cross-correlated behavior. Through the rolling window analysis, we find that the RMB exchange rates and international commodity prices are anti-persistent cross-correlated. The main sources of multifractality in the cross-correlations are long-range correlations between RMB exchange rate and the aggregate commodity, energy and metals index.

  10. A least squares method for a longitudinal fin with temperature dependent internal heat generation and thermal conductivity

    International Nuclear Information System (INIS)

    Aziz, A.; Bouaziz, M.N.

    2011-01-01

    Highlights: → Analytical solutions for a rectangular fin with temperature dependent heat generation and thermal conductivity. → Graphs give temperature distributions and fin efficiency. → Comparison of analytical and numerical solutions. → Method of least squares used for the analytical solutions. - Abstract: Approximate but highly accurate solutions for the temperature distribution, fin efficiency, and optimum fin parameter for a constant area longitudinal fin with temperature dependent internal heat generation and thermal conductivity are derived analytically. The method of least squares recently used by the authors is applied to treat the two nonlinearities, one associated with the temperature dependent internal heat generation and the other due to temperature dependent thermal conductivity. The solution is built from the classical solution for a fin with uniform internal heat generation and constant thermal conductivity. The results are presented graphically and compared with the direct numerical solutions. The analytical solutions retain their accuracy (within 1% of the numerical solution) even when there is a 60% increase in thermal conductivity and internal heat generation at the base temperature from their corresponding values at the sink temperature. The present solution is simple (involves hyperbolic functions only) compared with the fairly complex approximate solutions based on the homotopy perturbation method, variational iteration method, and the double series regular perturbation method and offers high accuracy. The simple analytical expressions for the temperature distribution, the fin efficiency and the optimum fin parameter are convenient for use by engineers dealing with the design and analysis of heat generating fins operating with a large temperature difference between the base and the environment.

  11. Internal Flow of Contra-Rotating Small Hydroturbine at Off- Design Flow Rates

    Science.gov (United States)

    SHIGEMITSU, Toru; TAKESHIMA, Yasutoshi; OGAWA, Yuya; FUKUTOMI, Junichiro

    2016-11-01

    Small hydropower generation is one of important alternative energy, and enormous potential lie in the small hydropower. However, efficiency of small hydroturbines is lower than that of large one. Then, there are demands for small hydroturbines to keep high performance in wide flow rate range. Therefore, we adopted contra-rotating rotors, which can be expected to achieve high performance. In this research, performance of the contra-rotating small hydroturbine with 60mm casing diameter was investigated by an experiment and numerical analysis. Efficiency of the contra-rotating small hydroturbine was high in pico-hydroturbine and high efficiency could be kept in wide flow rate range, however the performance of a rear rotor decreased significantly in partial flow rates. Then, internal flow condition, which was difficult to measure experimentally, was investigated by the numerical flow analysis. Then, a relation between the performance and internal flow condition was considered by the numerical analysis result.

  12. The Concept of State Capacity: Comparative International Ratings against State Legitimacy

    Directory of Open Access Journals (Sweden)

    Vladimir Gennadievich Ivanov

    2015-12-01

    Full Text Available In the given article, the author analyzes the concept of state capacity, widely popular among political scientists and international relations specialists. The author proves that the evaluations of the level of state capacity of the developing and postcommunist countries based on popular comparative ratings are generally biased because of methodological defects and discrepancy of the whole theory as well as politicization and indoctrination of the given ratings. The negative evaluations of the quality of the government and state capacity of a country could be used to discredit and delegitimize the political regime as well as substantiation of mass protests and color revolutions and a tool of information war. The author concludes that numerous comparative international ratings are often used as a tool of political influence.

  13. A review of fatal accident incidence rate trends in fishing international

    DEFF Research Database (Denmark)

    Jensen, Olaf; Pétursdóttir, G; Abrahamsen, Annbjørg

    2014-01-01

    Background. Injury prevention in fishing is one of the most important occupational health challenges. The aim was to describe and compare internationally the trends of the fatal injury incidence rates and to discuss the impact of the implemented safety programs. Methods. The review is based...... on journal articles and reports from the maritime authorities in Poland, UK, Norway, Iceland, Denmark, US and Alaska and Canada. The original incidence rates were recalculated as per 1000 person-years for international comparison of the trends. Results. The risk of fatal accidents in fishing in the northern...... countries has been reduced by around 50% to an average of about 1 per 1000 person-years. Norway and Canada keep the lowest rates with around 0.5 and 0.25 per 1000 person-years. About half of the fatal injuries are related to vessel disasters and drowning. The safety programs seem to have good effects still...

  14. Influence of product thickness, chamber pressure and heating conditions on production rate of freeze-dried yoghurt

    Energy Technology Data Exchange (ETDEWEB)

    Sharma, N.K. [G.B. Pant Univ., of Agriculture and Technology (India). Dept. of Mechanical Engineering; Arora, C.P. [Indian Inst. of Tech., New Delhi (India)

    1995-06-01

    The effects of product thickness, chamber pressure and heating conditions on product temperature profiles and production rate of freeze-dried yoghurt were investigated experimentally. Three sample thicknesses - 3.8 mm, 6.2 mm and 9.4 mm - were tested at chamber pressures of 0.01 and 0.5 mmHg. The production rate increased by decreasing product thickness in contact heating through the bottom of the frozen layer, whereas no significant change was observed in radiant heating. A reduction in chamber pressure from 0.50 to 0.01 mmHg increased the drying time in radiant heating. Maximum production rate was obtained when the thickness of dried product was 6.2 mm, when heat was transferred simultaneously through the frozen and dried layers, and the chamber pressure was at 0.01 mmHg. Use of the product tray developed in this study prevents the growth of dry layers at the contact surfaces. (Author)

  15. The impact of heat waves and cold spells on mortality rates in the Dutch population

    NARCIS (Netherlands)

    Huynen, M. M.; Martens, P.; Schram, D.; Weijenberg, M. P.; Kunst, A. E.

    2001-01-01

    We conducted the study described in this paper to investigate the impact of ambient temperature on mortality in the Netherlands during 1979-1997, the impact of heat waves and cold spells on mortality in particular, and the possibility of any heat wave- or cold spell-induced forward displacement of

  16. Modeling of Combined Heat and Power Plant Based on a Multi-Stage Gasifier and Internal Combustion Engines of Various Power Outputs

    Science.gov (United States)

    Khudyakova, G. I.; Kozlov, A. N.; Svishchev, D. A.

    2017-11-01

    The paper is concerned with an integrated system of internal combustion engine and mini combined heat and power plant (ICE-CHP). The system is based on multi-stage wood biomass gasification. The use of producer gas in the system affects negatively the internal combustion engine performance and, therefore, reduces the efficiency of the ICE-CHP plant. A mathematical model of an internal combustion engine running on low-calorie producer gas was developed using an overview of Russian and foreign manufacturers of reciprocating units, that was made in the research. A thermal calculation was done for four-stroke gas engines of different rated power outputs (30, 100 and 250 kW), running on producer gas (CO2 - 10.2, CO - 45.8, N2 - 38.8%). Thermal calculation demonstrates that the engine exhaust gas temperature reaches 500 - 600°C at the rated power level and with the lower engine power, the temperature gets higher. For example, for an internal combustion engine power of 1000 kW the temperature of exhaust gases equals 400°C. A comparison of the efficiency of engine operation on natural gas and producer gas shows that with the use of producer gas the power output declines from 300 to 250 kWe. The reduction in the effective efficiency in this case makes up 2%. The measures are proposed to upgrade the internal combustion engine to enable it to run on low-calorie producer gas.

  17. Linear Stability Analysis of Flow in an Internally Heated Rectangular Duct

    Energy Technology Data Exchange (ETDEWEB)

    Uhlmann, M.

    2004-07-01

    The linear stability of flow in a vertical rectangular duct subject to homogeneous internal heating, constant-temperature no-slip walls and a driving pressure gradient is investigated numerically. A full Chebyshevbased Galerkin method is found to be more reliable than a collocation method, both including the elimination of the pressure and the stream wise velocity from the system of equations and making use of the full symmetry properties. A classification of the mean flow-obtained as a function of Grashof and Reynolds numbers and the geometrical aspect ratio in terms of its inflectional properties is proposed. It is found that the flow loses stability at all aspects rations for a combination of finite thermal buoyancy and pressure forces with opposed sings. In the square duct, the unstable region coincides with the range where additional inflection lines are observed the mean velocity profile. Unstable eigenfunctions are obtained for all basic symmetry modes and their structure can be described as slightly elongated pockets of cross-stream-vertical motion, training each other along the stream wise direction. (Author) 22 refs.

  18. Relationship between particle and heat transport in JT-60U plasmas with internal transport barrier

    International Nuclear Information System (INIS)

    Takenaga, H.

    2002-01-01

    Relationship between particle and heat transport in an internal transport barrier (ITB) has been systematically investigated for the first time in reversed shear (RS) and high-β p ELMy H-mode (weak positive shear) plasmas of JT-60U for understanding of compatibility of improved energy confinement and effective particle control such as exhaust of helium ash and reduction in impurity contamination. In the RS plasma, no helium and carbon accumulation inside the ITB is observed even with highly improved energy confinement. In the high-β p plasma, both helium and carbon density profiles are flat. As the ion temperature profile changes from parabolic- to box-type, the helium diffusivity decreases by a factor of about 2 as well as the ion thermal diffusivity in the RS plasma. The measured soft X-ray profile is more peaked than that calculated by assuming the same n AR profile as the n e profile in the Ar injected RS plasma with the box-type profile, suggesting accumulation of Ar inside the ITB. Particle transport is improved with no change of ion temperature in the RS plasma, when density fluctuation is drastically reduced by a pellet injection. (author)

  19. Influence of heating rates on in situ resistance measurements of a bronze route Nb-Sn-Cu-Ta multifilamentary conductor

    International Nuclear Information System (INIS)

    Tan, K.S.; Hopkins, S.C.; Glowacki, B.A.

    2004-01-01

    The superconducting properties of a bronze process multifilamentary conductor are controlled by the structure, dimensions and composition of the intermetallic layers, which are strongly influenced by the details of the heat treatments applied to the conductor. It has previously been reported that the electrical resistivity of a Vacuumschmelze bronze process conductor varies during heat treatment, and that analysis of the conductor as a set of parallel resistors allows the features of the resistivity variation to be assigned to the progress of Nb 3 Sn intermetallic phase formation. The behaviour of NSP2 Nb-Sn-Cu-Ta bronze process multifilamentary conductors (Imperial Metal Industries) is now reported as a function of the heating rate, in preparation for more complex non-isothermal heat treatment procedures. It is shown that the resistance of the wire measured in situ by an alternating current (AC) technique can be used to observe the progress of the formation of Nb 3 Sn, and that the comparison of resistometric measurements at different heating rates can give an indication of other processes (such as recovery and recrystallisation) occurring at lower temperatures during the heating up process prior to isothermal annealing. In addition, this wire containing only about 1% of copper was carefully chosen because of the broken tantalum barriers around individual copper filaments. Therefore, the resistometric measurements were used to attempt to detect the diffusion of tin from the bronze matrix into the copper filaments at lower temperatures without noticeable influence on Nb 3 Sn phase formation. Treating the NSP2 wire as a set of parallel resistors also permits estimates to be made of the intermetallic layer thicknesses from resistometric measurements, and these are shown to be in good agreement with estimates from scanning electron microscopy. The difference in critical temperature, T c , between wires heated at different rates, with the presence of the bronze matrix

  20. Reduction of heat losses from greenhouses by means of internal blinds with low thermal emissivity

    NARCIS (Netherlands)

    Meijer, J.

    1980-01-01

    Heat losses in greenhouses may be substantially reduced by the use of heat reflecting blinds. Quantitative results are obtained solving a mathematical heat flow model by numerical methods. Special attention has been given to the emissivity and transmittance of the screen and the ventilation through

  1. Hypnosis modulates behavioural measures and subjective ratings about external and internal awareness.

    Science.gov (United States)

    Demertzi, Athena; Vanhaudenhuyse, Audrey; Noirhomme, Quentin; Faymonville, Marie-Elisabeth; Laureys, Steven

    2015-12-01

    In altered subjective states, the behavioural quantification of external and internal awareness remains challenging due to the need for reports on the subjects' behalf. With the aim to characterize the behavioural counterpart of external and internal awareness in a modified subjective condition, we used hypnosis during which subjects remain fully responsive. Eleven right-handed subjects reached a satisfactory level of hypnotisability as evidenced by subjective reports on arousal, absorption and dissociation. Compared to normal wakefulness, in hypnosis (a) participants' self-ratings for internal awareness increased and self-ratings for external awareness decreased, (b) the two awareness components tended to anticorrelate less and the switches between external and internal awareness self-ratings were less frequent, and (c) participants' reaction times were higher and lapses in key presses were more frequent. The identified imbalance between the two components of awareness is considered as of functional relevance to subjective (meta)cognition, possibly mediated by allocated attentional properties brought about by hypnosis. Our results highlight the presence of a cognitive counterpart in resting state, indicate that the modified contents of awareness are measurable behaviourally, and provide leverage for investigations of more challenging altered conscious states, such as anaesthesia, sleep and disorders of consciousness. Copyright © 2015 Elsevier Ltd. All rights reserved.

  2. Current status of and problems in ice heat storage systems contributing to improving load rate. Proliferation of the ice heat storage type air conditioning system and roles of the Heat Pump and Heat Storage Center; Fukaritsu kaizen ni kokensuru kori chikunetsu system no genjo to kadai. Kori chikunetsushiki kucho system no fukyu to heat pump chikunetsu center no yakuwari

    Energy Technology Data Exchange (ETDEWEB)

    Miyata, T.

    1998-02-01

    This paper introduces the roles played by the `Heat Pump and Heat Storage Center`. This foundation had been performing research and development and international information exchange in devices and equipment as the `Heat Pump Technology Development Center`. Development of heat storage type air conditioning systems as a measure for load leveling, and efforts of their proliferation and enlightenment were added to the business activities. As a result, the foundation`s name was changed to the present name. Its activities being planned and performed include: interest supplementing operation for installation of an air conditioning system of the heat pump system using storage of latent heat such as ice heat storage, holding seminars for promoting proliferation of the ice heat storage type air conditioning system, opening the home page, participation in exhibitions of various types, and preparation of different publicity tools. More specifically, carrying series advertisements in newspapers and magazines, holding nation-wide symposiums tying up with Japan Economic Press, publishing an organ newspaper targeted at both of experts and general people, and preparation of general pamphlets to introduce comprehensively the information about heat storage. 3 figs., 1 tab.

  3. Effect of heating rates of crystallization behaviour of amorphous Fe/sub 83/01/B/sub 17/ alloy

    International Nuclear Information System (INIS)

    Ashfaq, A.; Shamim, A.

    1993-01-01

    The electric resistivity of amorphous Fe/sub 83/01/B/sub 17/ alloy has been measured to study its crystallization behaviour from room temperature to about 900 K at the constant heating rates of 40, 60 and 80 K/hr. The crystallization temperature was observed to increase with the increase of heating g rate. However amorphous to crystalline path of RT-curve between the maximum and the minimum decreases with heating rate. The Resistivity Temperature (RT) curves exhibit different steps which are shown to correspond to the phase change stages of the alloy. The slope of the rt-curve after the previous step increases with the rise in heating rate and finally passes through a board peak and then rises again. From the peak shift dta of first crystallization stage activation energy was calculated by applying various peak shift equations. The values so obtained were in good agreement with those obtained with DSC measurement for (FeM)/sub 83/01/B/sub 17/ amorphous alloys where M=Mo, Ni, Cr, and V. (author)

  4. Comparison of the Heat Release Rate from the Mass Loss Calorimeter to the Cone Calorimeter for Wood-based Materials

    Science.gov (United States)

    Laura E. Hasburgh; Robert H. White; Mark A. Dietenberger; Charles R. Boardman

    2015-01-01

    There is a growing demand for material properties to be used as inputs in fi re behavior models designed to address building fire safety. This comparative study evaluates using the mass loss calorimeter as an alternative to the cone calorimeter for obtaining heat release rates of wood-based materials. For this study, a modified mass loss calorimeter utilized an...

  5. (Devaluing Intern Labour: Journalism Internship Pay Rates and Collective Representation in Canada

    Directory of Open Access Journals (Sweden)

    Errol Salamon

    2015-09-01

    Full Text Available Unpaid journalism internships have attracted increasing media coverage, but they have received limited scholarly attention. This paper traces the connections between trade unions (in unionized media organizations and the labour conditions marking journalism internships. While some unions can be complicit in sustaining the exploitation and devaluation of interns with regard to the standard market value of entry-level labour, other unions have fought to establish internships, locking higher salaries into collective agreements. Building on the concept of precarity, this article surveys internships at 19 mainstream English-language newspapers and magazines in Canada. It draws on documentary evidence from and personal communication with labour unions and journalism organizations, internship advertisements, and media coverage to offer a typology of the relationships between pay rates and collective representation within journalism internships: unpaid/low paid and not under union jurisdiction; unpaid/low paid and under union jurisdiction; paid at intern rates and not under union jurisdiction; paid at intern rates and under union jurisdiction; and paid at entry-level employee rates and under union jurisdiction.

  6. Classical entropy generation analysis in cooled homogenous and functionally graded material slabs with variation of internal heat generation with temperature, and convective–radiative boundary conditions

    International Nuclear Information System (INIS)

    Torabi, Mohsen; Zhang, Kaili

    2014-01-01

    This article investigates the classical entropy generation in cooled slabs. Two types of materials are assumed for the slab: homogeneous material and FGM (functionally graded material). For the homogeneous material, the thermal conductivity is assumed to be a linear function of temperature, while for the FGM slab the thermal conductivity is modeled to vary in accordance with the rule of mixtures. The boundary conditions are assumed to be convective and radiative concurrently, and the internal heat generation of the slab is a linear function of temperature. Using the DTM (differential transformation method) and resultant temperature fields from the DTM, the local and total entropy generation rates within slabs are derived. The effects of physically applicable parameters such as the thermal conductivity parameter for the homogenous slab, β, the thermal conductivity parameter for the FGM slab, γ, gradient index, j, internal heat generation parameter, Q, Biot number at the right side, Nc 2 , conduction–radiation parameter, Nr 2 , dimensionless convection sink temperature, δ, and dimensionless radiation sink temperature, η, on the local and total entropy generation rates are illustrated and explained. The results demonstrate that considering temperature- or coordinate-dependent thermal conductivity and radiation heat transfer at both sides of the slab have great effects on the entropy generation. - Highlights: • The paper investigates entropy generation in a slab due to heat generation and convective–radiative boundary conditions. • Both homogeneous material and FGM (functionally graded material) were considered. • The calculations are carried out using the differential transformation method which is a well-tested analytical technique

  7. The International Heat Stress Genotype Experiment for Modeling Wheat Response to Heat: Field Experiments and AgMIP-Wheat Multi-Model Simulations

    Science.gov (United States)

    Martre, Pierre; Reynolds, Matthew P.; Asseng, Senthold; Ewert, Frank; Alderman, Phillip D.; Cammarano, Davide; Maiorano, Andrea; Ruane, Alexander C.; Aggarwal, Pramod K.; Anothai, Jakarat; hide

    2017-01-01

    The data set contains a portion of the International Heat Stress Genotype Experiment (IHSGE) data used in the AgMIP-Wheat project to analyze the uncertainty of 30 wheat crop models and quantify the impact of heat on global wheat yield productivity. It includes two spring wheat cultivars grown during two consecutive winter cropping cycles at hot, irrigated, and low latitude sites in Mexico (Ciudad Obregon and Tlaltizapan), Egypt (Aswan), India (Dharwar), the Sudan (Wad Medani), and Bangladesh (Dinajpur). Experiments in Mexico included normal (November-December) and late (January-March) sowing dates. Data include local daily weather data, soil characteristics and initial soil conditions, crop measurements (anthesis and maturity dates, anthesis and final total above ground biomass, final grain yields and yields components), and cultivar information. Simulations include both daily in-season and end-of-season results from 30 wheat models.

  8. An Assessment of the Internal Rating Based Approach in Basel II

    OpenAIRE

    Simone Varotto

    2008-01-01

    The new bank capital regulation commonly known as Basel II includes a internal rating based approach (IRB) to measuring credit risk in bank portfolios. The IRB relies on the assumptions that the portfolio is fully diversified and that systematic risk is driven by one common factor. In this work we empirically investigate the impact of these assumptions by comparing the risk measures produced by the IRB with those of a more general credit risk model that allows for multiple systematic risk fac...

  9. Impact of Total, Internal and External Government Debt on Interest Rate in Pakistan

    OpenAIRE

    Perveen, Asma; Munir, Kashif

    2017-01-01

    The objective of the study is to examine impact of total, internal and external government debt on nominal interest rate in Pakistan. To attain these objectives, the study used annual time series data from 1973 to 2016. The study used loanable fund theory as theoretical model and ARDL bound testing approach for cointegration and Granger causality test to estimate the results. The results of the study found negative relation between total government debt, external debt and nominal interest rat...

  10. Success Rate and Complications of Internal Jugular Vein Catheterization With and Without Ultrasonography Guide

    OpenAIRE

    Karimi-Sari, Hamidreza; Faraji, Mehrdad; Mohazzab Torabi, Saman; Asjodi, Gholamreza

    2014-01-01

    Background: Central venous catheterization (CVC) is an important procedure in emergency departments (EDs). Despite existence of ultrasonography (US) devices in every ED, CVC is done using anatomical landmarks in many EDs in Iran. Objectives: This study aimed to compare the traditional landmark method vs. US-guided method of CVC placement in terms of complications and success rate. Patients and Methods: In this randomized controlled trial, patients who were candidate for internal jugular vein ...

  11. Book of presentations of the International Workshop on High Temperature Heat Pumps

    DEFF Research Database (Denmark)

    Modern society moves towards an electrifed energy system based on wind, solarand other renewable sources. Utilizing these sources effciently by heat pumps ishighly attractive and a significant potential for improving the energy system byextensive adaptation of heat pumping technology in all fields...... exists. However, challenges are present for heat pump technology. In particular for high temperature applications like industrial processes and to some extent district heating, heat pumps are not yet commercially available. In some countries the expansion already occurs, but other places the development...... is much more limited. Some obstacles relate to regulations and boundary conditions which may not be favorablefor heat pumps and electrification. But, the level of the technology willprobably also improve with regards to temperature limits, efficiency, capacity, and economy, and hence inherently become...

  12. Layout of an internally heated gas generator for the steam gasification of coal

    International Nuclear Information System (INIS)

    Feistel, P.P.; Duerrfeld, R.; Heck, K.H. van; Juentgen, H.

    1975-01-01

    Industrial-scale steam gasification of coal using heat from high temperature reactors requires research and development on allothermal gas generators. Bergbau-Forschung GmbH, Essen, does theoretical and experimental work in this field. The experiments deal with reaction kinetics, heat transfer and material tests. Their significance for the layout of a full-scale gas generator is shown. Including material specifications, the feasibility of a gasifier, characterized by a fluid bed volume of 318 m 3 and a heat transferring area of 4000 m 2 , results. The data, now available, are used to determine the gasification throughput from the heat balance, i.e. the equality of heat consumed and heat transferred. Throughputs of about 50 t/hr of coal are possible for a single gas generator, the helium outlet temperature of the HTR being 950 0 C/ Bergbau-Forschung has commissioned a medium-scale pilot plant (200 kg/hr). (Auth.)

  13. A study on the effects of system pressure on heat and mass transfer rates of an air cooler

    International Nuclear Information System (INIS)

    Jung, Hyung Ho

    2002-01-01

    In the present paper, the effects of inlet pressure on the heat and mass transfer rates of an air cooler are numerically predicted by a local analysis method. The pressures of the moist air vary from 2 to 4 bars. The psychometric properties such as dew point temperature, relative humidity and humidity ratio are employed to treat the condensing water vapor in the moist air when the surface temperatures are dropped below the dew point. The effects of the inlet pressures on the heat transfer rate, the dew point temperature, the rate of condensed water, the outlet temperature of air and cooling water are calculated. The condensation process of water vapor is discussed in detail. The results of present calculations are compared with the test data and shows good agreements

  14. Failure rate of inferior alveolar nerve block among dental students and interns.

    Science.gov (United States)

    AlHindi, Maryam; Rashed, Bayan; AlOtaibi, Noura

    2016-01-01

    To report the failure rate of inferior alveolar nerve block (IANB) among dental students and interns, causes of failure, investigate awareness of different IANB techniques, and to report IANB-associated complications.   A 3-page questionnaire containing 13 questions was distributed to a random sample of 350 third to fifth years students and interns at the College of Dentistry, King Saud University, Riyadh, Saudi Arabia on January 2011. It included demographic questions (age, gender, and academic level) and questions on IANB failure frequency and reasons, actions taken to overcome the failure, and awareness of different anesthetic techniques, supplementary techniques, and complications.   Of the 250 distributed questionnaires, 238 were returned (68% response rate). Most (85.7%) of surveyed sample had experienced IANB failure once or twice. The participants attributed the failures most commonly (66.45%) to anatomical variations. The most common alternative technique used was intraligamentary injection (57.1%), although 42.8% of the sample never attempted any alternatives. Large portion of the samples stated that they either lacked both knowledge of and training for other techniques (44.9%), or that they had knowledge of them but not enough training to perform them (45.8%).  To  decrease IANB failure rates for dental students and interns, knowledge of landmarks, anatomical variation and their training in alternatives to IANB, such as the Gow-Gates and Akinosi techniques, both theoretically and clinically in the dental curriculum should be enhanced.

  15. Failure rate of inferior alveolar nerve block among dental students and interns

    Directory of Open Access Journals (Sweden)

    Maryam AlHindi

    2016-01-01

    Full Text Available Objectives: To report the failure rate of inferior alveolar nerve block (IANB among dental students and interns, causes of failure, investigate awareness of different IANB techniques, and to report IANB-associated complications. Methods: A 3-page questionnaire containing 13 questions was distributed to a random sample of 350 third to fifth years students and interns at the College of Dentistry, King Saud University, Riyadh, Saudi Arabia on January 2011. It included demographic questions (age, gender, and academic level and questions on IANB failure frequency and reasons, actions taken to overcome the failure, and awareness of different anesthetic techniques, supplementary techniques, and complications. Results: Of the 250 distributed questionnaires, 238 were returned (68% response rate. Most (85.7% of surveyed sample had experienced IANB failure once or twice. The participants attributed the failures most commonly (66.45% to anatomical variations. The most common alternative technique used was intraligamentary injection (57.1%, although 42.8% of the sample never attempted any alternatives. Large portion of the samples stated that they either lacked both knowledge of and training for other techniques (44.9%, or that they had knowledge of them but not enough training to perform them (45.8%. Conclusion: To decrease IANB failure rates for dental students and interns, knowledge of landmarks, anatomical variation and their training in alternatives to IANB, such as the Gow-Gates and Akinosi techniques, both theoretically and clinically in the dental curriculum should be enhanced.

  16. Stylized facts in internal rates of return on stock index and its derivative transactions

    Science.gov (United States)

    Pichl, Lukáš; Kaizoji, Taisei; Yamano, Takuya

    2007-08-01

    Universal features in stock markets and their derivative markets are studied by means of probability distributions in internal rates of return on buy and sell transaction pairs. Unlike the stylized facts in normalized log returns, the probability distributions for such single asset encounters incorporate the time factor by means of the internal rate of return, defined as the continuous compound interest. Resulting stylized facts are shown in the probability distributions derived from the daily series of TOPIX, S & P 500 and FTSE 100 index close values. The application of the above analysis to minute-tick data of NIKKEI 225 and its futures market, respectively, reveals an interesting difference in the behavior of the two probability distributions, in case a threshold on the minimal duration of the long position is imposed. It is therefore suggested that the probability distributions of the internal rates of return could be used for causality mining between the underlying and derivative stock markets. The highly specific discrete spectrum, which results from noise trader strategies as opposed to the smooth distributions observed for fundamentalist strategies in single encounter transactions may be useful in deducing the type of investment strategy from trading revenues of small portfolio investors.

  17. Physiological responses to incremental exercise in the heat following internal and external precooling.

    Science.gov (United States)

    James, C A; Richardson, A J; Watt, P W; Gibson, O R; Maxwell, N S

    2015-06-01

    Twelve males completed three incremental, discontinuous treadmill tests in the heat [31.9(1.0) °C, 61.9(8.9)%] to determine speed at two fixed blood lactate concentrations (2 and 3.5 mmol/L), running economy (RE), and maximum oxygen uptake ( V ˙ O 2 m a x ). Trials involved 20 min of either internal cooling (ICE, 7.5 g/kg ice slurry ingestion) or mixed-methods external cooling (EXT, cold towels, forearm immersion, ice vest, and cooling shorts), alongside no intervention (CON). Following precooling, participants ran 0.3 km/h faster at 2 mmol/L and 0.2 km/h faster at 3.5 mmol/L (P = 0.04, partial η(2)  = 0.27). Statistical differences were observed vs CON for ICE (P = 0.03, d = 0.15), but not EXT (P = 0.12, d = 0.15). There was no effect of cooling on RE (P = 0.81, partial η(2)  = 0.02), nor on V ˙ O 2 m a x (P = 0.69, partial η(2)  = 0.04). An effect for cooling on physiological strain index was observed (P cooling groups (P cooling. Precooling appears to reduce blood lactate accumulation and reduce thermoregulatory and perceptual strain during incremental exercise. © 2015 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

  18. Low-energy office buildings using existing technology. Simulations with low internal heat gains

    Energy Technology Data Exchange (ETDEWEB)

    Flodberg, Kajsa; Blomsterberg, Aake; Dubois, Marie-Claude [Lund Univ. (Sweden). Div. of Energy and Building Design

    2012-11-01

    Although low-energy and nearly zero-energy residential houses have been built in Sweden in the past decade, there are very few examples of low-energy office buildings. This paper investigates the design features affecting energy use in office buildings and suggests the optimal low-energy design from a Swedish perspective. Dynamic simulations have been carried out with IDA ICE 4 on a typical narrow office building with perimeter cell rooms. The results from the parametric study reveal that the most important design features for energy saving are demand-controlled ventilation as well as limited glazing on the facade. Further energy-saving features are efficient lighting and office equipment which strongly reduce user-related electricity and cooling energy. Together, the simulation results suggest that about 48% energy can be saved compared to a new office building built according to the Swedish building code. Thus, it is possible, using a combination of simple and well-known building technologies and configurations, to have very low energy use in new office buildings. If renewable energy sources, such as solar energy and wind power, are added, there is a potential for the annual energy production to exceed the annual energy consumption and a net zero-energy building can be reached. One aspect of the results concerns user-related electricity, which becomes a major energy post in very low-energy offices and which is rarely regulated in building codes today. This results not only in high electricity use, but also in large internal heat gains and unnecessary high cooling loads given the high latitude and cold climate. (orig.)

  19. SISGR - In situ characterization and modeling of formation reactions under extreme heating rates in nanostructured multilayer foils

    Energy Technology Data Exchange (ETDEWEB)

    Hufnagel, Todd C.

    2014-06-09

    Materials subjected to extreme conditions, such as very rapid heating, behave differently than materials under more ordinary conditions. In this program we examined the effect of rapid heating on solid-state chemical reactions in metallic materials. One primary goal was to develop experimental techniques capable of observing these reactions, which can occur at heating rates in excess of one million degrees Celsius per second. One approach that we used is x-ray diffraction performed using microfocused x-ray beams and very fast x-ray detectors. A second approach is the use of a pulsed electron source for dynamic transmission electron microscopy. With these techniques we were able to observe how the heating rate affects the chemical reaction, from which we were able to discern general principles about how these reactions proceed. A second thrust of this program was to develop computational tools to help us understand and predict the reactions. From atomic-scale simulations were learned about the interdiffusion between different metals at high heating rates, and about how new crystalline phases form. A second class of computational models allow us to predict the shape of the reaction front that occurs in these materials, and to connect our understanding of interdiffusion from the atomistic simulations to measurements made in the laboratory. Both the experimental and computational techniques developed in this program are expected to be broadly applicable to a wider range of scientific problems than the intermetallic solid-state reactions studied here. For example, we have already begun using the x-ray techniques to study how materials respond to mechanical deformation at very high rates.

  20. An investigation of critical heat fluxes in vertical tubes internally cooled by Freon-12. Part I - Critical heat flux experiments with axially uniform and non-uniform heating and comparisons of data with selected correlations

    International Nuclear Information System (INIS)

    Green, W.J.; Stevens, J.R.

    1981-08-01

    Experiments have been performed using vertical heated tubes, cooled internally by Freon-12, to determine critical heat fluxes (CHFs) for both a uniformly heated section and an exit region with a separately controlled power supply. Heated lengths of the main separately were 2870 mm (8.48 and 16.76 mm tube bores) and 3700 mm (for 21.34 mm tube bore); heated length of the exit section was 230 mm. Coolant pressures, exit qualities and mass fluxes were in the range 0.9 to 1.3 MPa, 0.19 to 0.86, and 380 to 2800 kg m -2 s -1 , respectively. The data have been compared with published empirical correlations specifically formulated to predict CHFs in Freon-cooled, vertical tubes; relevant published CHF data have also been compared with these correlations. These comparisons show that, even over the ranges of conditions for which the correlations were developed, predicted values are only accurate to within +-20 per cent. Moreover, as mass fluxes increase above 3500 kg m -2 s -1 , the modified Groeneveld correlation becomes increasingly inadequate, and the Bertoletti and modified Bertoletti correlations under-predict CHF values by increasing amounts. At mass fluxes below 750 kg m -2 s -1 the Bertoletti correlations exhibit increasing inaccuracy with a decrease in mass flux. For non-uniform heating, the correlations are at variance with the experimental data

  1. Comparison of Journal Self-Citation Rates between Some Chinese and Non-Chinese International Journals

    Science.gov (United States)

    Yang, Zu-Guo; Gao, Feng; Zhang, Chun-Ting

    2012-01-01

    Background The past 3 decades have witnessed a boost in science development in China; in parallel, more and more Chinese scientific journals are indexed by the Journal Citation Reports issued by Thomson Reuters (SCI). Evaluation of the performance of these Chinese SCI journals is necessary and helpful to improve their quality. This study aimed to evaluate these journals by calculating various journal self-citation rates, which are important parameters influencing a journal impact factor. Methodology/Principal Findings We defined three journal self-citation rates, and studied these rates for 99 Chinese scientific journals, almost exhausting all Chinese SCI journals currently available. Likewise, we selected 99 non-Chinese international (abbreviated as ‘world’) journals, with each being in the same JCR subject category and having similar impact factors as their Chinese counterparts. Generally, Chinese journals tended to be higher in all the three self-citation rates than world journal counterparts. Particularly, a few Chinese scientific journals had much higher self-citation rates. Conclusions/Significance Our results show that generally Chinese scientific journals have higher self-citation rates than those of world journals. Consequently, Chinese scientific journals tend to have lower visibility and are more isolated in the relevant fields. Considering the fact that sciences are rapidly developing in China and so are Chinese scientific journals, we expect that the differences of journal self-citation rates between Chinese and world scientific journals will gradually disappear in the future. Some suggestions to solve the problems are presented. PMID:23173041

  2. Study of optimal operation management by a monitoring system for corrosion and heat-transfer rate of condensate pipe

    Energy Technology Data Exchange (ETDEWEB)

    Yasui, Katsmi; Kominami, Hirohiko; Atsumi, Tetsuro; Nagata, Koji (Kansai Electric Power Co., Inc., Osaka (Japan); Sumitomo Light Metal Industries Ltd., Tokyo (Japan))

    1988-09-26

    In order to optimize the anticorrosion and antifouling management of aluminum brass condensate pipes, the monitoring system was developed, which could control a corrosion resistance and heat transfer rate during operation. Since a polarization resistance could be used as an index for anticorrosion control, while a heat transmission coefficient or cleanliness factor for heat transfer control, a polarization resistance meter and fouling meter were made as prototype detectors. Fundamental test of a model condenser (simulated by-pass pipe) was performed using a processing system combined with the meters, and monitored data and analytical data of the test were arranged. System performance was ascertained to be preferable by the verification test on a real condenser, however, more compact system was required for practical use because of restriction in by-pass pipe installation. In addition to the monitoring function, a control function for sponge ball cleaning and iron ion injection was also added to keep the specified index value. 13 figs,. 1 tab.

  3. Application of multivariate adaptive regression spine-assisted objective function on optimization of heat transfer rate around a cylinder

    Energy Technology Data Exchange (ETDEWEB)

    Dey, Prasenjit; Dad, Ajoy K. [Mechanical Engineering Department, National Institute of Technology, Agartala (India)

    2016-12-15

    The present study aims to predict the heat transfer characteristics around a square cylinder with different corner radii using multivariate adaptive regression splines (MARS). Further, the MARS-generated objective function is optimized by particle swarm optimization. The data for the prediction are taken from the recently published article by the present authors [P. Dey, A. Sarkar, A.K. Das, Development of GEP and ANN model to predict the unsteady forced convection over a cylinder, Neural Comput. Appl. (2015). Further, the MARS model is compared with artificial neural network and gene expression programming. It has been found that the MARS model is very efficient in predicting the heat transfer characteristics. It has also been found that MARS is more efficient than artificial neural network and gene expression programming in predicting the forced convection data, and also particle swarm optimization can efficiently optimize the heat transfer rate.

  4. The effect of nitrogen gas flow rate on heat treatment of AISI SS-430: Study of microstructure and hardness

    Science.gov (United States)

    Sebayang, Perdamean; Darmawan, Bobby Aditya; Simbolon, Silviana; Alfirano, Sudiro, Toto; Aryanto, Didik

    2018-05-01

    The aim of this research was to obtain the austenite phase from ferritic stainless steel through sample heat treatment. The AISI 430 ferritic steel with the thickness of about 0.4 mm was used. The heat treatment was conducted in a tube furnace at elevated temperature of 1150, 1200, 1250 °C and nitrogen gas flow rate of 0.57 and 0.73 l/s. The samples were then rapidly quenched in water bath. An optical microscope, XRD, SEM-EDS and micro vickers hardness tester were used to characterize the sample before and after het treatment. The presence of anneal twins indicated the formation of austenite phase in the sample. Its fraction was varied from 10.89 wt% to 35.10 wt%. In addition, the heat treatment temperature strongly affected the sample hardness. The optimum hardness obtained was about 542.69 HV. According to the results, this material can be considered for biomedical applications.

  5. The effect of ultrasound irradiation on the convective heat transfer rate during immersion cooling of a stationary sphere.

    Science.gov (United States)

    Kiani, Hossein; Sun, Da-Wen; Zhang, Zhihang

    2012-11-01

    It has been proven that ultrasound irradiation can enhance the rate of heat transfer processes. The objective of this work was to study the heat transfer phenomenon, mainly the heat exchange at the surface, as affected by ultrasound irradiation around a stationary copper sphere (k=386W m(-1)K(-1), C(p)=384J kg(-1)K(-1), ρ=8660kg m(-3)) during cooling. The sphere (0.01m in diameter) was immersed in an ethylene glycol-water mixture (-10°C) in an ultrasonic cooling system that included a refrigerated circulator, a flow meter, an ultrasound generator and an ultrasonic bath. The temperature of the sphere was recorded using a data logger equipped with a T-type thermocouple in the center of the sphere. The temperature of the cooling medium was also monitored by four thermocouples situated at different places in the bath. The sphere was located at different positions (0.02, 0.04 and 0.06m) above the transducer surface of the bath calculated considering the center of the sphere as the center of the reference system and was exposed to different intensities of ultrasound (0, 120, 190, 450, 890, 1800, 2800, 3400 and 4100W m(-2)) during cooling. The frequency of the ultrasound was 25kHz. It was demonstrated that ultrasound irradiation can increase the rate of heat transfer significantly, resulting in considerably shorter cooling times. Higher intensities caused higher cooling rates, and Nu values were increased from about 23-27 to 25-108 depending on the intensity of ultrasound and the position of the sphere. However, high intensities of ultrasound led to the generation of heat at the surface of the sphere, thus limiting the lowest final temperature achieved. An analytical solution was developed considering the heat generation and was fitted to the experimental data with R(2) values in the range of 0.910-0.998. Visual observations revealed that both cavitation and acoustic streaming were important for heat transfer phenomenon. Cavitation clouds at the surface of the sphere

  6. Physiological and performance adaptations to an in-season soccer camp in the heat: Associations with heart rate and heart rate variability

    DEFF Research Database (Denmark)

    Buchheit, M; Voss, S C; Nybo, Lars

    2011-01-01

    The aim of the present study was to examine the associations between adaptive responses to an in-season soccer training camp in the heat and changes in submaximal exercising heart rate (HRex, 5-min run at 9 ¿km/h), postexercise HR recovery (HRR) and HR variability (HRV). Fifteen well-trained but ......The aim of the present study was to examine the associations between adaptive responses to an in-season soccer training camp in the heat and changes in submaximal exercising heart rate (HRex, 5-min run at 9 ¿km/h), postexercise HR recovery (HRR) and HR variability (HRV). Fifteen well......-trained but non-heat-acclimatized male adult players performed a training week in Qatar (34.6¿±¿1.9°C wet bulb globe temperature). HRex, HRR, HRV (i.e. the standard deviation of instantaneous beat-to-beat R-R interval variability measured from Poincaré plots SD1, a vagal-related index), creatine kinase (CK...... at the beginning and at the end of the training week. Throughout the intervention, HRex and HRV showed decreasing (P¿...

  7. Temperature and heat flux scaling laws for isoviscous, infinite Prandtl number mixed heating convection.

    Science.gov (United States)

    Vilella, Kenny; Deschamps, Frederic

    2018-04-01

    Thermal evolution of terrestrial planets is controlled by heat transfer through their silicate mantles. A suitable framework for modelling this heat transport is a system including bottom heating (from the core) and internal heating, e.g., generated by secular cooling or by the decay of radioactive isotopes. The mechanism of heat transfer depends on the physical properties of the system. In systems where convection is able to operate, two different regimes are possible depending on the relative amount of bottom and internal heating. For moderate internal heating rates, the system is composed of active hot upwellings and cold downwellings. For large internal heating rates, the bottom heat flux becomes negative and the system is only composed of active cold downwellings. Here, we build theoretical scaling laws for both convective regimes following the approach of Vilella & Kaminski (2017), which links the surface heat flux and the temperature jump across both the top and bottom thermal boundary layer (TBL) to the Rayleigh number and the dimensionless internal heating rate. Theoretical predictions are then verified against numerical simulations performed in 2D and 3D-Cartesian geometry, and covering a large range of the parameter space. Our theoretical scaling laws are more successful in predicting the thermal structure of systems with large internal heating rates than that of systems with no or moderate internal heating. The differences between moderate and large internal heating rates are interpreted as differences in the mechanisms generating thermal instabilities. We identified three mechanisms: conductive growth of the TBL, instability impacting, and TBL erosion, the last two being present only for moderate internal heating rates, in which hot plumes are generated at the bottom of the system and are able to reach the surface. Finally, we apply our scaling laws to the evolution of the early Earth, proposing a new model for the cooling of the primordial magma ocean

  8. Investigation of char strength and expansion properties of an intumescent coating exposed to rapid heating rates

    DEFF Research Database (Denmark)

    Nørgaard, Kristian Petersen; Dam-Johansen, Kim; Català, Pere

    2013-01-01

    , char properties, measured at room temperature, were dependent on the preceding storage conditions (in air or in a desiccator). The char was found to have the highest mechanical strength against compression in the outer crust facing the heat source. For thin (147μm) free coating films, a tendency...... with respect to the mechanical resistance against compression, degree of expansion, and residual mass fraction. Experimental results show that when using this type of shock heating, the mechanical resistance of the char against compression cannot meaningfully be correlated to the expansion factor. In addition...

  9. Analysis of heat and mass transfer to determine heat loss and the rate of condensation of the MVSTs off-gas ducts

    International Nuclear Information System (INIS)

    Ebadian, M.A.; Yang, G.; Bigzadeh, E.; Walker, J.F.; Abraham, T.J.

    1992-01-01

    Reduction of the existing nuclear waste in the Melton Valley Storage Tanks (MVSTs) at the Oak Ridge National Laboratory (ORNL) is of utmost concern to the scientists at this facility. This paper provides proof that a combination of vault heating, sparged air heating, and prevention of condensation is the best alternative to achieve this goal. Therefore, in this study a general system of mathematical equations has been developed taking into account all of the parameters affecting evaporation and condensation. This evaporation process has been analyzed by the careful modeling of a bubble chain through the extremely viscous, radioactive liquid contained in the storage tanks. This paper discusses in detail the evaporation procedure using bubble formation, air velocity, and determining the rate at which this liquid waste can be removed from the MVSTs by evaporation under different conditons of the sparging air. An additional objective is to study the heating/cooling of the condensation process of the off-gas piping inside the vault. A laboratory scale model has also been assembled for this purpose at ORNL to verify the accuracy of the mathematical modeling. A comparison of the experimental findings with the mathematical modeling shows excellent agreement. (orig.)

  10. Evaluation of subcooled critical heat flux correlations for tubes with and without internal twisted tapes

    International Nuclear Information System (INIS)

    Inasaka, F.; Nariai, H.

    1996-01-01

    Eleven correlations and models for critical heat flux (CHF) of subcooled flow boiling in water were evaluated. Both a direct substitution method (DSM) and a heat balance condition method (HBM) were compared in the evaluations. The HBM was recommended as a better prediction method in the present study. For straight tubes under uniform heating conditions, the correlations of the Gunther, Knoebel, modified Tong, W-2, and Tong-75, and also the Celata and Weisman-Pei models were confirmed to give reasonably good predictions. Among them, the Celata model was the best with respect to accuracy. For swirl flow under uniform heating conditions, Tong-75-I (involving modification of the water velocity parameter) and Nariai-Inasaka correlations were confirmed to give reasonably good predictions, even though their predictions were too low for the CHF under non-uniform heating conditions. (orig.)

  11. Temporary heat storage by using combined heat and power in supplementary lighted greenhouses Proceedings of the Third International Symposium on Artificial Lighting in Horticulture

    NARCIS (Netherlands)

    Huijs, J.P.G.

    1997-01-01

    Because of better utilization possibilities of the produced heat, decentrally located combined heat and power installations achieve a higher energetic efficiency than producing heat and power separately. However, efficiency depends considerably on synchronism of heat and electricity demand. Using a

  12. Effect of melt surface depression on the vaporization rate of a metal heated by an electron beam

    International Nuclear Information System (INIS)

    Guilbaud, D.

    1995-01-01

    In order to produce high density vapor, a metal confined in a water cooled crucible is heated by an electron beam (eb). The energy transfer to the metal causes partial melting, forming a pool where the flow is driven by temperature induced buoyancy and capillary forces. Furthermore, when the vaporization rate is high, the free surface is depressed by the thrust of the vapor. The main objective of this paper is to analyse the combined effects of liquid flow and vapor condensation back on the liquid surface. This is done with TRIO-EF, a general purpose fluid mechanics finite element code. A suitable iterative scheme is used to calculate the free surface flow and the temperature field. The numerical simulation gives an insight about the influence of the free surface in heat transfer. The depression of the free surface induces strong effects on both liquid and vapor. As liquid is concerned, buoyancy convection in the pool is enhanced, the energy flux from electron beam is spread and constriction of heat flux under the eb spot is weakened. It results that heat transfer towards the crucible is reinforced. As vapor is concerned, its fraction that condenses back on the liquid surface is increased. These phenomena lead to a saturation of the net vaporization rate as the eb spot radius is reduced, at constant eb power. (author). 8 refs., 13 figs., 2 tabs

  13. Enhancement of Condensation Heat Transfer Rate of the Air-Steam Mixture on a Passive Condenser System Using Annular Fins

    Directory of Open Access Journals (Sweden)

    Yeong-Jun Jang

    2017-11-01

    Full Text Available This paper presents an experimental investigation on the enhancement of the heat transfer rate of steam condensation on the external surfaces of a vertical tube with annular fins. A cylindrical condenser tube, which is 40 mm in outer diameter and 1000 mm in length, with annular disks of uniform cross-sectional area is fabricated in the manner of ensuring perfect contact between the base surface and fins. A total of 13 annular fins of 80 mm diameter were installed along the tube height in order to increase the effective heat transfer area by 85%. Through a series of condensation tests for the air-steam mixture under natural convection conditions, the heat transfer data was measured in the pressure range of between 2 and 5 bar, and the air mass fraction from 0.3 to 0.7. The rates of heat transfer of the finned tube are compared to those that are measured on a bare tube to demonstrate the enhanced performance by extended surfaces. In addition, based on the experimental results and the characteristics of steam condensation, the applicability of finned tubes to a large condenser system with a bundle layout is evaluated.

  14. Fiscal 2000 project of inviting proposals for international joint research - invitation for international proposal (Energy conservation No.3). Achievement report on development of micro-scale boiling aided high efficiency heat removing device; 2000 nendo kokusai kyodo kenkyu teian kobo jigyo - kokusai teian kobo (shoe No.3). Micro scale boiling ni yoru kokoritsu honetsu device no kaihatsu seika hokokusho

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    2001-03-01

    Studies are conducted about basic matters of heat transfer with boiling, such as critical heat flux intensification, prevention of dry-out, and the development of refrigerants suitable for use for heat transfer with boiling, for the purpose of developing boiling heat conduction type high-efficiency heat removing devices for use in electronics, and then heat removing devices usable as power devices in the future are experimentally designed. Activities are conducted in the three fields of (1) the study of basic micro-boiling technology, (2) development of micro-scale boiling element technology, and (3) international joint studies. Efforts are made to develop the technology of removing heat from ultrahigh heat fluxes using a micro-valve in field (1), to develop the technology of heat transfer by boiling in a micro-channel in field (2); and to develop the technology of critical heat flux intensification in a boiling heat exchanger in an electromagnetic field (3). In an effort to develop the technology of heat removal, a heat transfer plate is installed at the bottom of a path which is narrow, horizontal, and rectangular, and distilled water is allowed to flow and boil. Micro-bubble emission boiling occurs by a subcooling degree of 40K at an average flow rate of 0.5 m/s, and an ultrahigh heat flux of 2-7 times 10{sup 6} W/m{sup 2} is obtained. The value is 2-4 times as high as the current IC chip critical heat flux. (NEDO)

  15. Thermal resistance of rotating closed-loop pulsating heat pipes: Effects of working fluids and internal diameters

    Directory of Open Access Journals (Sweden)

    Kammuang-Lue Niti

    2017-01-01

    Full Text Available The objective of this study was to experimentally investigate the effects of working fluids and internal diameters on the thermal resistance of rotating closed-loop pul¬sating heat pipes (RCLPHP. The RCLPHP were made of a copper tube with internal diameters of 1.50 mm and 1.78 mm, bent into the shape of a flower petal, and arranged into a circle with 11 turns. The evaporator section was located at the outer end of the tube bundle. R123, ethanol, and water were filled as the working fluids. The RCLPHP was rotated at centrifugal accelerations 0.5, 1, 3, 5, 10, and 20 times of the gravitational acceleration considered at the connection between the evaporator and the condenser sections. The heat input was varied from 30 W to 50 W, and then to 100 W, 150 W, and 200 W. It can be concluded that when the latent heat of evaporation increases, the pressure difference between the evaporator and the condenser sections decreases, and the thermal resistance increases. Moreover, when the internal diameter increases, the driving force increases and the frictional force proportionally decreases, or the Karman number increases, and the thermal resistance decreases.

  16. Subjective ratings and performance in the heat and after sleep deprivation

    NARCIS (Netherlands)

    Daanen, H.A.M.; Ling, S. van; Tan, T.K.

    2013-01-01

    Background: It has been shown that endurance performance after one night of sleep deprivation is not compromised despite the feeling of fatigue and that, in contrast, performance in the heat deteriorates even though people may feel good. However, it is essentially unknown how the estimation of

  17. Coolant material effect on the heat transfer rates of the molten metal pool with solidification

    International Nuclear Information System (INIS)

    Cho, Jae Seon; Suh, Kune Y.; Chung, Chang Hyun; Park, Rae Joon; Kim, Sang Baik

    1998-01-01

    Experimental studies on heat transfer and solidification of the molten metal pool with overlying coolant with boiling were performed. The simulant molten pool material is tin (Sn) with the melting temperature of 232 degree C. Demineralized water and R113 are used as the working coolant. This work examines the crust formation and the heat transfer characteristics of the molten metal pool immersed in the boiling coolant. The Nusselt number and the Rayleigh number in the molten metal pool region of this study are compared between the water coolant case and the R113 coolant case. The experimental results for the water coolant are higher than those for R113. Also, the empirical relationship of the Nusselt number and the Rayleigh number is compared with the literature correlations measured from mercury. The present experimental results are higher than the literature correlations. It is believed that this discrepancy is caused by the effect of the heat loss to the environment on the natural convection heat transfer in the molten pool

  18. Research on the trend of Yen exchange rate and international crude oil price fluctuation affected by Japan’s earthquake

    Directory of Open Access Journals (Sweden)

    Xiaoguang Li

    2014-05-01

    Full Text Available Purpose: Whether this earthquake would become a turning point of the high oil price and whether it would have big impact on yen exchange rate are two issues to be discussed in this paper.Design/methodology/approach: To analyze deeply the internal relations between changes in yen exchange rate caused by Japan’s earthquake and price fluctuation of international crude oil, this research chooses middle rate of yen exchange rate during the 45 days around Japan’s earthquake and price data of international crude oil to do an empirical study, uses VAR model and HP trend decomposition to estimate the mutual effect of yen exchange rate change and price fluctuation of international crude oil in this period.Findings: It has been found in the empirical study with VAR model and HP filter decomposition model on the yen exchange rate and the international crude oil price fluctuation during 45 days around Japan’s earthquake that: the fluctuation of yen exchange rate around the earthquake is one of the main reasons for the drastic fluctuation of international crude oil price in that period. The fluctuation of international crude oil price directly triggered by yen exchange rate occupies 13.54% of its total variance. There is a long-term interactive relationship between yen exchange rate and international crude oil price. The upward trend of international crude oil price after the earthquake was obvious, while yen exchange rate remained relatively stable after the earthquake.Originality/value: As economic globalization goes deeper, the influence of natural disasters on international financial market and world economy will become more and more obvious. It has a great revelatory meaning to studying further each kind of natural disaster’s impacts on international financial market and world economics.

  19. Interaction of heat production, strain rate and stress power in a plastically deforming body under tensile test

    Science.gov (United States)

    Paglietti, A.

    1982-01-01

    At high strain rates the heat produced by plastic deformation can give rise to a rate dependent response even if the material has rate independent constitutive equations. This effect has to be evaluated when interpreting a material test, or else it could erroneously be ascribed to viscosity. A general thermodynamic theory of tensile testing of elastic-plastic materials is given in this paper; it is valid for large strain at finite strain rates. It enables discovery of the parameters governing the thermodynamic strain rate effect, provides a method for proper interpretation of the results of the tests of dynamic plasticity, and suggests a way of planning experiments in order to detect the real contribution of viscosity.

  20. Hydration rate and strength development of low-heat type portland cement mortar mixed with pozzolanic materials

    International Nuclear Information System (INIS)

    Matsui, Jun

    1998-01-01

    Recently, low-heat type Portland cement was specified in Japan Industrial Standards (JIS). Its hydration proceeds slowly. The results of the research so far obtained indicate that slow hydration of cement and mixing of pozzolanic materials with cement make micro-structure of harded cement paste dense and durable. In this study, a blended cement using low-heat type Portland cement and some of pozzolanic materials has been newly developed and its strength property and hydration ratio were checked. The followings are conclusion. (1) Hydration rate of cement paste varies with the replacement ratio of pozzolanic materials. (2) A good liner relationship between strength and total hydration rate of cement paste was observed. (3) A proper replacement ratio of both base-cement and pozzolanic material for manufacturing a blended cement is 50%. (author)

  1. An artificial intelligence (AI) NOx/heat rate optimization system for Ontario Hydro`s fossil generating stations

    Energy Technology Data Exchange (ETDEWEB)

    Luk, J.; Frank, A.; Bodach, P. [Ontario Hydro, Toronto, ON (Canada); Warriner, G. [Radian International, Tucker, GA (United States); Noblett, J. [Radian International, Austin, TX (United States); Slatsky, M. [Southern Company, Birmingham, AL (United States)

    1999-08-01

    Artificial intelligence (AI)-based software packages which can optimize power plant operations that improves heat rate and also reduces nitrogen oxide emissions are now commonly available for commercial use. This paper discusses the implementation of the AI-based NOx and Heat Rate Optimization System at Ontario Hydro`s generation stations, emphasizing the current AI Optimization Project at Units 5 and 6 of the Lakeview Generating Station. These demonstration programs are showing promising results in NOx reduction and plant performance improvement. The availability of the plant Digital Control System (DCS) in implementing AI optimization in a closed-loop system was shown to be an important criterion for success. Implementation of AI technology at other Ontario Hydro fossil generating units as part of the overall NOx emission reduction system is envisaged to coincide with the retrofit of the original plant control system with the latest DCS systems. 14 refs., 3 figs.

  2. Determination of mass flow rate and quality distributions between the subchannels of a heated bundle. [BWR; PWR

    Energy Technology Data Exchange (ETDEWEB)

    Bayoumi, M.; Charlot, R.; Ricque, R.

    1976-05-01

    For analyzing, correlating and extrapolating experimental burn-out results obtained with LWR rod bundles, it is necessary to know the distributions of mass flow rate and quality between the subchannels. A description is presented of an experimental study in progress at the CEN-Grenoble for determining and adjusting the laws of mixing in the FLICA Code which is used to predict these distributions. The experiments are performed on the FRENESIE loop with Freon 12. The test section, in vertical position, consists of a four rod bundle in a channel with square section. The heat flux is axially uniform. The flow of each subchannel can be sampled in ''isokinetic conditions,'' at the end of the heating length. Thermodynamic quality and mass flow rate of the samplings are measured in steady state conditions by using respectively a calorimeter and a turbine flow meter. The test facility is described and experimental data are presented and discussed.

  3. Characterization of ion heat conduction in JET and ASDEX Upgrade plasmas with and without internal transport barriers

    Energy Technology Data Exchange (ETDEWEB)

    Wolf, R C [Institut fuer Plasmaphysik, Forschungszentrum Juelich, Association EURATOM/FZJ, Trilateral Euregio Cluster, D-52425 Juelich (Germany); Baranov, Y [UKAEA/EURATOM Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Garbet, X [Association EURATOM-CEA sur la fusion, CEA Cadarache, F-13108 St Paul lez Durance (France); Hawkes, N [UKAEA/EURATOM Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Peeters, A G [Max-Planck-Institut fuer Plasmaphysik, EURATOM-Assoziation, D-85748 Garching (Germany); Challis, C [UKAEA/EURATOM Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom); Baar, M de [FOM Instituut voor Plasmafyisica Rijnhuizen, Association EURATO-FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Giroud, C [FOM Instituut voor Plasmafyisica Rijnhuizen, Association EURATO-FOM, Trilateral Euregio Cluster, PO Box 1207, 3430 BE Nieuwegein (Netherlands); Joffrin, E [Association EURATOM-CEA sur la fusion, CEA Cadarache, F-13108 St Paul lez Durance (France); Mantsinen, M [Helsinki University of Technology, Association-EURATOM Tekes, FIN-02015 HUT (Finland); Mazon, D [Association EURATOM-CEA sur la fusion, CEA Cadarache, F-13108 St Paul lez Durance (France); Meister, H [Max-Planck-Institut fuer Plasmaphysik, EURATOM-Assoziation, D-85748 Garching (Germany); Suttrop, W [Max-Planck-Institut fuer Plasmaphysik, EURATOM-Assoziation, D-85748 Garching (Germany); Zastrow, K-D [UKAEA/EURATOM Fusion Association, Culham Science Centre, Abingdon, OX14 3DB (United Kingdom)

    2003-09-01

    In ASDEX Upgrade and JET, the ion temperature profiles can be described by R/L{sub Ti} which exhibits only little variations, both locally, when comparing different discharges, and radially over a wide range of the poloidal cross-section. Considering a change of the local ion heat flux of more than a factor of two, this behaviour indicates some degree of profile stiffness. In JET, covering a large ion temperature range from 1 to 25 keV, the normalized ion temperature gradient, R/L{sub Ti}, shows a dependence on the electron to ion temperature ratio or toroidal rotational shear. In particular, in hot ion plasmas, produced predominantly by neutral beam heating at low densities, in which large T{sub i}/T{sub e} is coupled to strong toroidal rotation, the effect of the two quantities cannot be distinguished. Both in ASDEX Upgrade and JET, plasmas with internal transport barriers (ITBs), including the PEP mode in JET, are characterized by a significant increase of R/L{sub Ti} above the value of L- and H-mode plasmas. In agreement with previous ASDEX Upgrade results, no increase of the ion heat transport in reversed magnetic shear ITB plasmas is found in JET when raising the electron heating. Evidence is presented that magnetic shear directly influences R/L{sub Ti}, namely decreasing the ion heat transport when going from weakly positive to negative magnetic shear.

  4. HEATING6 analysis of international thermal benchmark problem sets 1 and 2

    International Nuclear Information System (INIS)

    Childs, K.W.; Bryan, C.B.

    1986-10-01

    In order to assess the heat transfer computer codes used in the analysis of nuclear fuel shipping casks, the Nuclear Energy Agency Committee on Reactor Physics has defined seven problems for benchmarking thermal codes. All seven of these problems have been solved using the HEATING6 heat transfer code. This report presents the results of five of the problems. The remaining two problems were used in a previous benchmarking of thermal codes used in the United States, and their solutions have been previously published

  5. THE MANAGEMENT OF CREDIT RISK ACCORDING TO INTERNAL RATINGS- BASED APPROACH

    Directory of Open Access Journals (Sweden)

    BOLOCAN DRAGOS-MIHAIL

    2010-12-01

    Full Text Available The internal ratings based approach (IRB Approach was created as part of Basel II replacing the original Basle Accord of 1988 (Basle I in an effort to create a better framework for regulating bank capital. This paper covers the methodology and components of the IRB Approach used to determine capital requirements for credit risk. Such an approach, which relies heavily upon a banks internal assessment of its counterparties and exposures, can secure two key objectives consistent with those which support the wider review of The New Basel Capital Accord.. IRB approach should promote safety and soundness in the financial system and, consistent with providing incentive compatibility, that the structure and requirements of the IRB approach do not impinge upon or undermine banks well-established lending and credit risk management practices

  6. Vertical profiles of aerosol optical properties and the solar heating rate estimated by combining sky radiometer and lidar measurements

    Science.gov (United States)

    Kudo, Rei; Nishizawa, Tomoaki; Aoyagi, Toshinori

    2016-07-01

    The SKYLIDAR algorithm was developed to estimate vertical profiles of aerosol optical properties from sky radiometer (SKYNET) and lidar (AD-Net) measurements. The solar heating rate was also estimated from the SKYLIDAR retrievals. The algorithm consists of two retrieval steps: (1) columnar properties are retrieved from the sky radiometer measurements and the vertically mean depolarization ratio obtained from the lidar measurements and (2) vertical profiles are retrieved from the lidar measurements and the results of the first step. The derived parameters are the vertical profiles of the size distribution, refractive index (real and imaginary parts), extinction coefficient, single-scattering albedo, and asymmetry factor. Sensitivity tests were conducted by applying the SKYLIDAR algorithm to the simulated sky radiometer and lidar data for vertical profiles of three different aerosols, continental average, transported dust, and pollution aerosols. The vertical profiles of the size distribution, extinction coefficient, and asymmetry factor were well estimated in all cases. The vertical profiles of the refractive index and single-scattering albedo of transported dust, but not those of transported pollution aerosol, were well estimated. To demonstrate the performance and validity of the SKYLIDAR algorithm, we applied the SKYLIDAR algorithm to the actual measurements at Tsukuba, Japan. The detailed vertical structures of the aerosol optical properties and solar heating rate of transported dust and smoke were investigated. Examination of the relationship between the solar heating rate and the aerosol optical properties showed that the vertical profile of the asymmetry factor played an important role in creating vertical variation in the solar heating rate. We then compared the columnar optical properties retrieved with the SKYLIDAR algorithm to those produced with the more established scheme SKYRAD.PACK, and the surface solar irradiance calculated from the SKYLIDAR

  7. NLP modeling for the optimization of LiBr-H2O absorption refrigeration systems with exergy loss rate, heat transfer area, and cost as single objective functions

    DEFF Research Database (Denmark)

    Mussati, Sergio F.; Gernaey, Krist; Morosuk, Tatiana

    2016-01-01

    exergy loss rate, the total heat transfer area, and the total annual cost of the system. It was found that the optimal solution obtained by minimization of the total exergy loss rate provides “theoretical” upper bounds not only for the total heat transfer area of the system but also for each process unit...... and all stream temperatures, while the optimal solution obtained by minimization of the total heat transfer area provides the lower bounds for these model variables, to solve a cost optimization problem. The minimization of the total exergy loss rate by varying parametrically the available total heat...... transfer area between these bounds was also performed, allowing to see how the optimal distribution of the available total heat transfer area among the system components, as well as the operating conditions (stream temperature, pressure, composition, and mass flow rate) and heat loads, vary qualitatively...

  8. Flow structure and heat exchange analysis in internal cooling channel of gas turbine blade

    Science.gov (United States)

    Szwaba, Ryszard; Kaczynski, Piotr; Doerffer, Piotr; Telega, Janusz

    2016-08-01

    This paper presents the study of the flow structure and heat transfer, and also their correlations on the four walls of a radial cooling passage model of a gas turbine blade. The investigations focus on heat transfer and aerodynamic measurements in the channel, which is an accurate representation of the configuration used in aeroengines. Correlations for the heat transfer coefficient and the pressure drop used in the design of radial cooling passages are often developed from simplified models. It is important to note that real engine passages do not have perfect rectangular cross sections, but include corner fillet, ribs with fillet radii and special orientation. Therefore, this work provides detailed fluid flow and heat transfer data for a model of radial cooling geometry which possesses very realistic features.

  9. Personalized Hydration Strategy Attenuates the Rise in Heart Rate and in Skin Temperature Without Altering Cycling Capacity in the Heat

    Directory of Open Access Journals (Sweden)

    Denise de Melo-Marins

    2018-04-01

    Full Text Available The optimal hydration plan [i.e., drink to thirst, ad libitum (ADL, or personalized plan] to be adopted during exercise in recreational athletes has recently been a matter of debate and, due to conflicting results, consensus does not exist. In the present investigation, we tested whether a personalized hydration strategy based on sweat rate would affect cardiovascular and thermoregulatory responses and exercise capacity in the heat. Eleven recreational male cyclists underwent two familiarization cycling sessions in the heat (34°C, 40% RH where sweat rate was also determined. A fan was used to enhance sweat evaporation. Participants then performed three randomized time-to-exhaustion (TTE trials in the heat with different hydration strategies: personalized volume (PVO, where water was consumed, based on individual sweat rate, every 10 min; ADL, where free access to water was allowed; and a control (CON trial with no fluids. Blood osmolality and urine-specific gravity were measured before each trial. Heart rate (HR, rectal, and skin temperatures were monitored throughout trials. Time to exhaustion at 70% of maximal workload was used to define exercise capacity in the heat, which was similar in all trials (p = 0.801. Body mass decreased after ADL (p = 0.008 and CON (p < 0.001 and was maintained in PVO trials (p = 0.171. Participants consumed 0 ml in CON, 166 ± 167 ml in ADL, and 1,080 ± 166 ml in PVO trials. The increase in mean body temperature was similar among trials despite a lower increase in skin temperature during PVO trial in comparison with CON (2.1 ± 0.6 vs. 2.9 ± 0.5°C, p = 0.0038. HR was lower toward the end of TTE in PVO (162 ± 8 bpm in comparison with ADL (168 ± 12 bpm and CON (167 ± 10 bpm, p < 0.001. In conclusion, a personalized hydration strategy can reduce HR during a moderate to high intensity exercise session in the heat and halt the increase in skin

  10. Personalized Hydration Strategy Attenuates the Rise in Heart Rate and in Skin Temperature Without Altering Cycling Capacity in the Heat.

    Science.gov (United States)

    de Melo-Marins, Denise; Souza-Silva, Ana Angélica; da Silva-Santos, Gabriel Lucas Leite; Freire-Júnior, Francisco de Assis; Lee, Jason Kai Wei; Laitano, Orlando

    2018-01-01

    The optimal hydration plan [i.e., drink to thirst, ad libitum (ADL), or personalized plan] to be adopted during exercise in recreational athletes has recently been a matter of debate and, due to conflicting results, consensus does not exist. In the present investigation, we tested whether a personalized hydration strategy based on sweat rate would affect cardiovascular and thermoregulatory responses and exercise capacity in the heat. Eleven recreational male cyclists underwent two familiarization cycling sessions in the heat (34°C, 40% RH) where sweat rate was also determined. A fan was used to enhance sweat evaporation. Participants then performed three randomized time-to-exhaustion (TTE) trials in the heat with different hydration strategies: personalized volume (PVO), where water was consumed, based on individual sweat rate, every 10 min; ADL, where free access to water was allowed; and a control (CON) trial with no fluids. Blood osmolality and urine-specific gravity were measured before each trial. Heart rate (HR), rectal, and skin temperatures were monitored throughout trials. Time to exhaustion at 70% of maximal workload was used to define exercise capacity in the heat, which was similar in all trials ( p  = 0.801). Body mass decreased after ADL ( p  = 0.008) and CON ( p  skin temperature during PVO trial in comparison with CON (2.1 ± 0.6 vs. 2.9 ± 0.5°C, p  = 0.0038). HR was lower toward the end of TTE in PVO (162 ± 8 bpm) in comparison with ADL (168 ± 12 bpm) and CON (167 ± 10 bpm), p  hydration strategy can reduce HR during a moderate to high intensity exercise session in the heat and halt the increase in skin temperature. Despite these advantages, cycling capacity in the heat remained unchanged.

  11. Internal thermotopography and shifts in general thermal balance in man under special heat transfer conditions

    Science.gov (United States)

    Gorodinskiy, S. M.; Gramenitskiy, P. M.; Kuznets, Y. I.; Ozerov, O. Y.; Yakovleva, E. V.; Groza, P.; Kozlovskiy, S.; Naremski, Y.

    1974-01-01

    Thermal regulation for astronauts working in pressure suits in open space provides for protection by a system of artificial heat removal and compensation to counteract possible changes in the heat regulating function of the human body that occur under the complex effects of space flight conditions. Most important of these factors are prolonged weightlessness, prolonged limitation of motor activity, and possible deviations of microclimatic environmental parameters.

  12. Thermionic nuclear reactor with internal heat distribution and multiple duct cooling

    Science.gov (United States)

    Fisher, C.R.; Perry, L.W. Jr.

    1975-11-01

    A Thermionic Nuclear Reactor is described having multiple ribbon-like coolant ducts passing through the core, intertwined among the thermionic fuel elements to provide independent cooling paths. Heat pipes are disposed in the core between and adjacent to the thermionic fuel elements and the ribbon ducting, for the purpose of more uniformly distributing the heat of fission among the thermionic fuel elements and the ducts.

  13. Numerical study of plasma generation process and internal antenna heat loadings in J-PARC RF negative ion source

    Energy Technology Data Exchange (ETDEWEB)

    Shibata, T., E-mail: shibat@post.j-parc.jp; Ueno, A.; Oguri, H.; Ohkoshi, K.; Ikegami, K.; Takagi, A.; Asano, H.; Naito, F. [J-PARC Center, Tokai-mura, Naka-gun, Ibaraki-ken 319-1195 (Japan); Nishida, K.; Mochizuki, S.; Hatayama, A. [Keio University, Hiyoshi, Kohoku-ku, Yokohama-shi, Kanagawa-ken 223-8522 (Japan); Mattei, S.; Lettry, J. [European Organization for Nuclear Research (CERN), 1211 Geneva 23 (Switzerland)

    2016-02-15

    A numerical model of plasma transport and electromagnetic field in the J-PARC (Japan Proton Accelerator Research Complex) radio frequency ion source has been developed to understand the relation between antenna coil heat loadings and plasma production/transport processes. From the calculation, the local plasma density increase is observed in the region close to the antenna coil. Electrons are magnetized by the magnetic field line with absolute magnetic flux density 30–120 Gauss which leads to high local ionization rate. The results suggest that modification of magnetic configuration can be made to reduce plasma heat flux onto the antenna.

  14. Literature Reviews on Modeling Internal Geometry of Textile Composites and Rate-Independent Continuum Damage

    Science.gov (United States)

    Su-Yuen, Hsu

    2011-01-01

    Textile composite materials have good potential for constructing composite structures where the effects of three-dimensional stresses are critical or geometric complexity is a manufacturing concern. There is a recent interest in advancing competence within Langley Research Center for modeling the degradation of mechanical properties of textile composites. In an initial effort, two critical areas are identified to pursue: (1) Construction of internal geometry of textile composites, and (2) Rate-independent continuum damage mechanics. This report documents reviews on the two subjects. Various reviewed approaches are categorized, their assumptions, methods, and progress are briefed, and then critiques are presented. Each review ends with recommended research.

  15. Effect of longwall face advance rate on spontaneous heating process in the gob area - CFD modelling

    Czech Academy of Sciences Publication Activity Database

    Taraba, B.; Michalec, Zdeněk

    2011-01-01

    Roč. 90, č. 8 (2011), s. 2790-2797 ISSN 0016-2361 R&D Projects: GA ČR GA105/06/0630 Grant - others:GA ČR(CZ) GA105/08/1414 Institutional research plan: CEZ:AV0Z30860518 Keywords : coal oxidation * spontaneous heating * CFD modelling * Fluent Subject RIV: DH - Mining, incl. Coal Mining Impact factor: 3.248, year: 2011 http://www.sciencedirect.com/science/article/pii/S0016236111001724

  16. Final results of the 'Benchmark on computer simulation of radioactive nuclides production rate and heat generation rate in a spallation target'

    International Nuclear Information System (INIS)

    Janczyszyn, J.; Pohorecki, W.; Domanska, G.; Maiorino, R.J.; David, J.C.; Velarde, F.A.

    2011-01-01

    A benchmark has been organized to assess the computer simulation of nuclide production and heat generation in a spallation lead target. The physical models applied for the calculation of thick lead target activation do not produce satisfactory results for the majority of analysed nuclides, however one can observe better or worse quantitative compliance with the experimental results. Analysis of the quality of calculated results show the best performance for heavy nuclides (A: 170 - 190). For intermediate nuclides (A: 60 - 130) almost all are underestimated while for A: 130 - 170 mainly overestimated. The shape of the activity distribution in the target is well reproduced in calculations by all models but the numerical comparison shows similar performance as for the whole target. The Isabel model yields best results. As for the whole target heating rate, the results from all participants are consistent. Only small differences are observed between results from physical models. As for the heating distribution in the target it looks not quite similar. The quantitative comparison of the distributions yielded by different spallation reaction models shows for the major part of the target no serious differences - generally below 10%. However, in the most outside parts of the target front layers and the part of the target at its end behind the primary protons range, a spread higher than 40 % is obtained

  17. Comparison of Analytical and Numerical Performance Predictions for a Regenerative Heat Exchanger in the International Space Station Node 3 Internal Active Thermal Control System

    Science.gov (United States)

    Wise, Stephen A.; Holt, James M.; Turner, Larry D. (Technical Monitor)

    2001-01-01

    The complexity of International Space Station (ISS) systems modeling often necessitates the concurrence of various dissimilar, parallel analysis techniques to validate modeling. This was the case with a feasibility and performance study of the ISS Node 3 Regenerative Heat Exchanger (RHX). A thermo-hydraulic network model was created and analyzed in SINDA/FLUINT. A less complex, closed form solution of the system dynamics was created using Excel. The purpose of this paper is to provide a brief description of the modeling processes utilized, the results and benefits of each to the ISS Node 3 RHX study.

  18. Comparison of Analytical and Numerical Performance Predictions for an International Space Station Node 3 Internal Active Thermal Control System Regenerative Heat Exchanger

    Science.gov (United States)

    Wise, Stephen A.; Holt, James M.

    2002-01-01

    The complexity of International Space Station (ISS) systems modeling often necessitates the concurrence of various dissimilar, parallel analysis techniques to validate modeling. This was the case with a feasibility and performance study of the ISS Node 3 Regenerative Heat Exchanger (RHX). A thermo-hydraulic network model was created and analyzed in SINDA/FLUINT. A less complex, closed form solution of the systems dynamics was created using an Excel Spreadsheet. The purpose of this paper is to provide a brief description of the modeling processes utilized, the results and benefits of each to the ISS Node 3 RHX study.

  19. Low internal pressure in femtoliter water capillary bridges reduces evaporation rates.

    Science.gov (United States)

    Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Weon, Byung Mook

    2016-03-01

    Capillary bridges are usually formed by a small liquid volume in a confined space between two solid surfaces. They can have a lower internal pressure than the surrounding pressure for volumes of the order of femtoliters. Femtoliter capillary bridges with relatively rapid evaporation rates are difficult to explore experimentally. To understand in detail the evaporation of femtoliter capillary bridges, we present a feasible experimental method to directly visualize how water bridges evaporate between a microsphere and a flat substrate in still air using transmission X-ray microscopy. Precise measurements of evaporation rates for water bridges show that lower water pressure than surrounding pressure can significantly decrease evaporation through the suppression of vapor diffusion. This finding provides insight into the evaporation of ultrasmall capillary bridges.

  20. Low internal pressure in femtoliter water capillary bridges reduces evaporation rates

    Science.gov (United States)

    Cho, Kun; Hwang, In Gyu; Kim, Yeseul; Lim, Su Jin; Lim, Jun; Kim, Joon Heon; Gim, Bopil; Weon, Byung Mook

    2016-01-01

    Capillary bridges are usually formed by a small liquid volume in a confined space between two solid surfaces. They can have a lower internal pressure than the surrounding pressure for volumes of the order of femtoliters. Femtoliter capillary bridges with relatively rapid evaporation rates are difficult to explore experimentally. To understand in detail the evaporation of femtoliter capillary bridges, we present a feasible experimental method to directly visualize how water bridges evaporate between a microsphere and a flat substrate in still air using transmission X-ray microscopy. Precise measurements of evaporation rates for water bridges show that lower water pressure than surrounding pressure can significantly decrease evaporation through the suppression of vapor diffusion. This finding provides insight into the evaporation of ultrasmall capillary bridges. PMID:26928329

  1. Automatic heating control system

    Energy Technology Data Exchange (ETDEWEB)

    Whittle, A.J.

    1989-11-15

    A heating control system for buildings comprises at least one heater incorporating heat storage means, a first sensor for detecting temperature within the building, means for setting a demand temperature, a second sensor for detecting outside temperature, a timer, and means for determining the switch on time of the heat storage means on the basis of the demand temperature and the internal and external temperatures. The system may additionally base the switch on time of the storage heater(s) on the heating and cooling rates of the building (as determined from the sensed temperatures); or on the anticipated daytime temperature (determined from the sensed night time temperature). (author).

  2. Rheology and microstructure of binary mixed gel of rice bran protein-whey: effect of heating rate and whey addition.

    Science.gov (United States)

    Rafe, Ali; Vahedi, Elnaz; Hasan-Sarei, Azadeh Ghorbani

    2016-08-01

    Rice bran protein (RBP) is a valuable plant protein which has unique nutritional and hypoallergenic properties. Whey proteins have wide applications in the food industry, such as in dairy, meat and bakery products. Whey protein concentrate (WPC), RBP and their mixtures at different ratios (1:1, 1:2, 1:5 and 1:10 w/w) were heated from 20 to 90 °C at different heating rates (0.5, 1, 5 and 10 °C min(-1) ). The storage modulus (G') and gelling point (Tgel ) of WPC were higher than those of RBP, indicating the good ability of WPC to develop stiffer networks. By increasing the proportion of WPC in mixed systems, G' was increased and Tgel was reduced. Nevertheless, the elasticity of all binary mixtures was lower than that of WPC alone. Tgel and the final G' of RBP-WPC blends were increased by raising the heating rate. The RBP-WPC mixtures developed more elastic gels than RBP alone at different heating rates. RBP had a fibrillar and lentil-like structure whose fibril assembly had smaller structures than those of WPC. The gelling structure of the mixed gel of WPC-RBP was improved by adding WPC. Indeed, by adding WPC, gels tended to show syneresis and had lower water-holding capacity. Furthermore, the gel structure was produced by adding WPC to the non-gelling RBP, which is compatible with whey and can be applied as a functional food for infants and/or adults. © 2015 Society of Chemical Industry. © 2015 Society of Chemical Industry.

  3. Experimental Methodology for Estimation of Local Heat Fluxes and Burning Rates in Steady Laminar Boundary Layer Diffusion Flames.

    Science.gov (United States)

    Singh, Ajay V; Gollner, Michael J

    2016-06-01

    Modeling the realistic burning behavior of condensed-phase fuels has remained out of reach, in part because of an inability to resolve the complex interactions occurring at the interface between gas-phase flames and condensed-phase fuels. The current research provides a technique to explore the dynamic relationship between a combustible condensed fuel surface and gas-phase flames in laminar boundary layers. Experiments have previously been conducted in both forced and free convective environments over both solid and liquid fuels. A unique methodology, based on the Reynolds Analogy, was used to estimate local mass burning rates and flame heat fluxes for these laminar boundary layer diffusion flames utilizing local temperature gradients at the fuel surface. Local mass burning rates and convective and radiative heat feedback from the flames were measured in both the pyrolysis and plume regions by using temperature gradients mapped near the wall by a two-axis traverse system. These experiments are time-consuming and can be challenging to design as the condensed fuel surface burns steadily for only a limited period of time following ignition. The temperature profiles near the fuel surface need to be mapped during steady burning of a condensed fuel surface at a very high spatial resolution in order to capture reasonable estimates of local temperature gradients. Careful corrections for radiative heat losses from the thermocouples are also essential for accurate measurements. For these reasons, the whole experimental setup needs to be automated with a computer-controlled traverse mechanism, eliminating most errors due to positioning of a micro-thermocouple. An outline of steps to reproducibly capture near-wall temperature gradients and use them to assess local burning rates and heat fluxes is provided.

  4. Measurement of fission gas release, internal pressure and cladding creep rate in the fuel pins of PHWR bundle of normal discharge burnup

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, U.K. [Post Irradiation Examination Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Sah, D.N., E-mail: dnsah@barc.gov.i [Post Irradiation Examination Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India); Rath, B.N.; Anantharaman, S. [Post Irradiation Examination Division, Bhabha Atomic Research Centre, Trombay, Mumbai 400085 (India)

    2009-08-01

    Fuel pins of a Pressurised Heavy Water Reactor (PHWR) fuel bundle discharged from Narora Atomic Power Station unit no. 1 after attaining a fuel burnup of 7528 MWd/tU have been subjected to two types of studies, namely (i) puncture test to estimate extent of fission gas release and internal pressure in the fuel pin and (ii) localized heating of the irradiated fuel pin to measure the creep rate of the cladding in temperature range 800 deg. C - 900 deg. C. The fission gas release in the fuel pins from the outer ring of the bundle was found to be about 8%. However, only marginal release was found in fuel pins from the middle ring and the central fuel pin. The internal gas pressure in the outer fuel pin was measured to be 0.55 +- 0.05 MPa at room temperature. In-cell isothermal heating of a small portion of the outer fuel pins was carried out at 800 deg. C, 850 deg. C and 900 deg. C for 10 min and the increase in diameter of the fuel pin was measured after heat treatment. Creep rates of the cladding obtained from the measurement of the diameter change of the cladding due to heating at 800 deg. C, 850 deg. C and 900 deg. C were found respectively to be 2.4 x 10{sup -5} s{sup -1}, 24.6 x 10{sup -5} s{sup -1} and 45.6 x 10{sup -5} s{sup -1}.

  5. Study of heat removal by natural convection from the internal core catcher in PFBR using water model experiments

    International Nuclear Information System (INIS)

    Jasmin Sudha, A.; Punitha, G.; Das, S.K.; Lydia, G.; Murthy, S.S.; Malarvizhi, B.; Harvey, J.; Kannan, S.E.

    2005-01-01

    Full text of publication follows: In the event of a core meltdown accident in a Fast Breeder Reactor, the molten core material settling on the bottom of the main vessel can endanger the structural integrity of the main vessel. In the design of Prototype Fast Breeder Reactor in India, the construction of which is about to commence, a core catcher is provided as the internal core retention device to collect and retain the core debris in a coolable configuration. Heat transfer by natural convection above and below the core catcher plate, in the zone beneath the core support structure is evaluated from water mockup experiments in the 1:4 geometrically scaled setup. These studies were undertaken towards comparison of experimentally measured temperatures at different locations with the numerical results. The core catcher assembly consists of a core catcher plate, a heat shield plate and a chimney. Decay heat from the core debris is simulated by electrical heating of the heat shield plate. An opening is provided in the cover plate to reproduce the situation in the actual accident where the core debris would have breached a part of the core support structure. Experiments were carried out with different heat flux levels prevailing upon the heat shield plate. Temperature monitoring was done at more than 100 locations, distributed both on the solid components and in water. The temperature data was analysed to get the temperature profile at different steady state conditions. Flow visualisation was also carried out using water soluble dye to establish the direction of the convective currents. The captured images show that water flows through the slots provided in the top portion of the chimney in the upward direction as evidenced from the diffusion of dye injected inside the chimney. Both the temperature data and flow visualisation confirm mixing of water through the opening in the core support structure which indicates that natural convection is set up in that zone

  6. Excess heat from kraft pulp mills: Trade-offs between internal and external use in the case of Sweden-Part 1: Methodology

    International Nuclear Information System (INIS)

    Svensson, Inger-Lise; Joensson, Johanna; Berntsson, Thore; Moshfegh, Bahram

    2008-01-01

    Excess heat from a kraft pulp mill can be used either internally to increase the level of efficiency in the mill, or externally for example as district heating. This paper presents an approach to investigate the competition between external and internal use through modelling the pulp mill and an energy company (ECO) within the same system boundary. Three different sizes of ECOs with different district heating demands are studied. To investigate the competitiveness of using industrial excess heat as district heating compared with other heat production techniques, the option of investing in excess heat use is introduced, along with the possibility for the ECO to invest in biomass combined heat and power (CHP), waste CHP and natural gas combined cycle (NGCC). To evaluate the robustness of the model, alternative solutions are identified and will be used as a comparison to the optimal solutions. The model has been verified by comparing the results with previous studies concerning kraft pulp mills and with related studies regarding district heating and real ECOs. Finally, the approach presented in this part of the study will be used in the second part in order to investigate the trade-off between internal and external use of excess heat under different future energy market scenarios

  7. Second international comparison on measuring techniques of tritium production rate for fusion neutronics experiments (ICMT-2)

    International Nuclear Information System (INIS)

    Maekawa, Fujio; Maekawa, Hiroshi

    1993-02-01

    An second international comparison on measuring techniques of tritium production rates for fusion neutronics experiments (ICMT-2) has been performed. The purpose is to evaluate the measurement accuracy of tritium production rates in the current measurement techniques. Two 14 MeV neutron source facilities, FNS at JAERI-Japan and LOTUS at EPFL-Switzerland, were used for this purpose. Nine groups out of seven countries participated in this program. A fusion simulated blanket assembly of simple-geometry was served as the test bed at each facility, in which Li-containing samples from the participants were irradiated in an uniform neutron field. The tritium production rates were determined by the participants using their own ways by using the liquid scintillation counting method. Tritiated water sample with unknown but the same concentration was also distributed and its concentration was measured to make a common reference. The standard deviation of measured tritium production rates among participants was about 10 % for both FNS and LOTUS irradiation levels: 4x10 -13 T-atoms/Li-atom and 1.6x10 -12 T-atoms/Li-atom at a sample, respectively. This standard deviation exceeds the expected deviation of 5 % in this program. It is presumed that the deviation of 10 % is caused mainly by the systematic and unknown errors in a process of tritium extraction from the irradiated samples depending on each organization. (author)

  8. Cooling of an internal-heated debris bed with fine particles

    International Nuclear Information System (INIS)

    Yang, Z.L.; Sehgal, B.R.

    2001-01-01

    In this paper, an analytical model on dryout heat flux of ex-vessel debris beds with fines particles under top flooding conditions has been developed. The parametric study is performed on the effect of the stratification of the debris beds on the dryout heat flux. The calculated results show that the stratification configuration of the debris beds with smaller particles and lower porosity layer resting on the top of another layer of the beds has profound effect on the dryout heat flux for the debris beds both with and without a downcomer. The enhancement of the dryout heat flux by the downcomer is significant. The efficiency of the single downcomer on the enhancement of the dryout heat flux is also analyzed. This, in general, agrees well with experimental data. The model is also employed to perform the assessment on the coolability of the ex-vessel debris bed under representative accidental conditions. One conservative case is chosen, and it is found that the downcomer could be efficient measure to cool the debris bed and hence terminate the severe accident. (authors)

  9. Heat Transfer Computations of Internal Duct Flows With Combined Hydraulic and Thermal Developing Length

    Science.gov (United States)

    Wang, C. R.; Towne, C. E.; Hippensteele, S. A.; Poinsatte, P. E.

    1997-01-01

    This study investigated the Navier-Stokes computations of the surface heat transfer coefficients of a transition duct flow. A transition duct from an axisymmetric cross section to a non-axisymmetric cross section, is usually used to connect the turbine exit to the nozzle. As the gas turbine inlet temperature increases, the transition duct is subjected to the high temperature at the gas turbine exit. The transition duct flow has combined development of hydraulic and thermal entry length. The design of the transition duct required accurate surface heat transfer coefficients. The Navier-Stokes computational method could be used to predict the surface heat transfer coefficients of a transition duct flow. The Proteus three-dimensional Navier-Stokes numerical computational code was used in this study. The code was first studied for the computations of the turbulent developing flow properties within a circular duct and a square duct. The code was then used to compute the turbulent flow properties of a transition duct flow. The computational results of the surface pressure, the skin friction factor, and the surface heat transfer coefficient were described and compared with their values obtained from theoretical analyses or experiments. The comparison showed that the Navier-Stokes computation could predict approximately the surface heat transfer coefficients of a transition duct flow.

  10. Novel Method for Measuring the Heat Collection Rate and Heat Loss Coefficient of Water-in-Glass Evacuated Tube Solar Water Heaters Based on Artificial Neural Networks and Support Vector Machine

    Directory of Open Access Journals (Sweden)

    Zhijian Liu

    2015-08-01

    Full Text Available The determinations of heat collection rate and heat loss coefficient are crucial for the evaluation of in service water-in-glass evacuated tube solar water heaters. However, the direct determination requires complex detection devices and a series of standard experiments, which also wastes too much time and manpower. To address this problem, we propose machine learning models including artificial neural networks (ANNs and support vector machines (SVM to predict the heat collection rate and heat loss coefficient without a direct determination. Parameters that can be easily obtained by “portable test instruments” were set as independent variables, including tube length, number of tubes, tube center distance, heat water mass in tank, collector area, final temperature and angle between tubes and ground, while the heat collection rate and heat loss coefficient determined by the detection device were set as dependent variables respectively. Nine hundred fifteen samples from in-service water-in-glass evacuated tube solar water heaters were used for training and testing the models. Results show that the multilayer feed-forward neural network (MLFN with 3 nodes is the best model for the prediction of heat collection rate and the general regression neural network (GRNN is the best model for the prediction of heat loss coefficient due to their low root mean square (RMS errors, short training times, and high prediction accuracies (under the tolerances of 30%, 20%, and 10%, respectively.

  11. The relationship between experimental geometry, heat rate, and ultrasound wave speed measurement while observing phase changes in highly attenuative materials

    Science.gov (United States)

    Moore, David G.; Stair, Sarah L.; Jack, David A.

    2018-04-01

    Ultrasound techniques are capable of monitoring changes in the time-of-flight as a material is exposed to different thermal environments. The focus of the present study is to identify the phase of a material via ultrasound compression wave measurements in a through transmission experimental setup as the material is heated from a solid to a liquid and then allowed to re-solidify. The present work seeks to expand upon the authors' previous research, which proved this through transmission phase monitoring technique was possible, by considering different experimental geometries. The relationship between geometry, the measured speed of sound, and the temperature profile is presented. The use of different volumes helps in establishing a baseline understanding of which aspects of the experiment are geometry dependent and which are independent. The present study also investigates the relationship between the heating rate observed in the experiment and the measured speed of sound. The trends identified between the experimental geometry, heat rate and ultrasound wave speed measurement assist in providing a baseline understanding of the applicability of this technique to various industries, including the polymer industry and the oil industry.

  12. Investigation of inhomogeneous deformation in band amorphous alloys at constant heating rate

    Science.gov (United States)

    Fedorov, Victor; Berezner, Arseniy; Pluzhnikova, Tatiana; Beskrovnyi, Anatolyi

    2017-11-01

    The present paper contains investigations of the creep process in the cobalt-based amorphous metallic alloy within the temperature range from 300 up to 1023 K. In all the curves of deformation there were observed jumps and dying oscillations. It is noted that the creep of the sample ribbons is unstable and results in the thinning of ribbons with tightening and crimping. There is suggested the mechanism of inhomogeneous deformation, which takes place in course of the process of creep under intermittent heating. For the evaluation of amorphism in the treated samples there have been carried out neutron-graphical and X-ray diffraction investigations, as well as thermal analysis.

  13. Critical temperature gradient length signatures in heat wave propagation across internal transport barriers in the Joint European Torus

    International Nuclear Information System (INIS)

    Casati, Alessandro; Mantica, P.; Eester, D. van; Hawkes, N.; De Vries, P.; Imbeaux, F.; Joffrin, E.; Marinoni, A.; Ryter, F.; Salmi, A.; Tala, T.

    2007-01-01

    New results on electron heat wave propagation using ion cyclotron resonance heating power modulation in the Joint European Torus (JET) [P. H. Rebut et al., Nucl. Fusion 25, 1011 (1985)] plasmas characterized by internal transport barriers (ITBs) are presented. The heat wave generated outside the ITB, and traveling across it, always experiences a strong damping in the ITB layer, demonstrating a low level of transport and loss of stiffness. In some cases, however, the heat wave is strongly inflated in the region just outside the ITB, showing features of convective-like behavior. In other cases, a second maximum in the perturbation amplitude is generated close to the ITB foot. Such peculiar types of behavior can be explained on the basis of the existence of a critical temperature gradient length for the onset of turbulent transport. Convective-like features appear close to the threshold (i.e., just outside the ITB foot) when the value of the threshold is sufficiently high, with a good match with the theoretical predictions for the trapped electron mode threshold. The appearance of a second maximum is due to the oscillation of the temperature profile across the threshold in the case of a weak ITB. Simulations with an empirical critical gradient length model and with the theory based GLF23 [R. E. Waltz et al., Phys. Plasmas, 4, 2482 (1997)] model are presented. The difference with respect to previous results of cold pulse propagation across JET ITBs is also discussed

  14. Heat Conductivity Resistance of Concrete Wall Panel by Water Flowing in Different Orientations of Internal PVC pipe

    Science.gov (United States)

    Umi, N. N.; Norazman, M. N.; Daud, N. M.; Yusof, M. A.; Yahya, M. A.; Othman, M.

    2018-04-01

    Green building technology and sustainability development is current focus in the world nowadays. In Malaysia and most tropical countries the maximum temperature recorded typically at 35°C. Air-conditioning system has become a necessity in occupied buildings, thereby increasing the cost of electric consumption. The aim of this study is to find out the solution in minimizing heat transfer from the external environment and intentions towards going green. In this study, the experimental work includes testing three types of concrete wall panels. The main heat intervention material in this research is 2 inch diameter Polyvinyl Chloride (PVC) pipe embedded at the center of the concrete wall panel, while the EPS foam beads were added to the cement content in the concrete mix forming the outer layer of the wall panel. Water from the rainwater harvesting system is regulated in the PVC pipe to intervene with the heat conductivity through the wall panel. Results from the experimental works show that the internal surface temperature of these heat resistance wall panels is to 3□C lower than control wall panel from plain interlocking bricks.

  15. Fuel formulation and mixing strategy for rate of heat release control with PCCI combustion

    NARCIS (Netherlands)

    Zegers, R.P.C.; Yu, M.; Luijten, C.C.M.; Dam, N.J.; Baert, R.S.G.; Goey, de L.P.H.

    2009-01-01

    Premixed charge compression ignition (or PCCI) is a new combustion concept that promises very low emissions of nitrogen oxides and of particulate matter by internal combustion engines. In the PCCIcombustion mode fuel, products from previous combustion events and air are mixed and compresseduntil the

  16. International Energy Agency's Heat Pump Centre (IEA-HPC) Annual National Team Working Group Meeting

    Science.gov (United States)

    Broders, M. A.

    1992-09-01

    The traveler, serving as Delegate from the United States Advanced Heat Pump National Team, participated in the activities of the fourth IEA-HPC National Team Working Group meeting. Highlights of this meeting included review and discussion of 1992 IEA-HPC activities and accomplishments, introduction of the Switzerland National Team, and development of the 1993 IEA-HPC work program. The traveler also gave a formal presentation about the Development and Activities of the IEA Advanced Heat Pump U.S. National Team.

  17. Influence of heat and shear induced protein aggregation on the in vitro digestion rate of whey proteins.

    Science.gov (United States)

    Singh, Tanoj K; Øiseth, Sofia K; Lundin, Leif; Day, Li

    2014-11-01

    Protein intake is essential for growth and repair of body cells, the normal functioning of muscles, and health related immune functions. Most food proteins are consumed after undergoing various degrees of processing. Changes in protein structure and assembly as a result of processing impact the digestibility of proteins. Research in understanding to what extent the protein structure impacts the rate of proteolysis under human physiological conditions has gained considerable interest. In this work, four whey protein gels were prepared using heat processing at two different pH values, 6.8 and 4.6, with and without applied shear. The gels showed different protein network microstructures due to heat induced unfolding (at pH 6.8) or lack of unfolding, thus resulting in fine stranded protein networks. When shear was applied during heating, particulate protein networks were formed. The differences in the gel microstructures resulted in considerable differences in their rheological properties. An in vitro gastric and intestinal model was used to investigate the resulting effects of these different gel structures on whey protein digestion. In addition, the rate of digestion was monitored by taking samples at various time points throughout the in vitro digestion process. The peptides in the digesta were profiled using SDS-polyacrylamide gel electrophoresis, reversed-phase-HPLC and LC-MS. Under simulated gastric conditions, whey proteins in structured gels were hydrolysed faster than native proteins in solution. The rate of peptides released during in vitro digestion differed depending on the structure of the gels and extent of protein aggregation. The outcomes of this work highlighted that changes in the network structure of the protein can influence the rate and pattern of its proteolysis under gastrointestinal conditions. Such knowledge could assist the food industry in designing novel food formulations to control the digestion kinetics and the release of biologically

  18. Working fluid selection for the Organic Rankine Cycle (ORC) exhaust heat recovery of an internal combustion engine power plant

    Science.gov (United States)

    Douvartzides, S.; Karmalis, I.

    2016-11-01

    Organic Rankine cycle technology is capable to efficiently convert low-grade heat into useful mechanical power. In the present investigation such a cycle is used for the recovery of heat from the exhaust gases of a four stroke V18 MAN 51/60DF internal combustion engine power plant operating with natural gas. Design is focused on the selection of the appropriate working fluid of the Rankine cycle in terms of thermodynamic, environmental and safety criteria. 37 candidate fluids have been considered and all Rankine cycles examined were subcritical. The thermodynamic analysis of all fluids has been comparatively undertaken and the effect of key operation conditions such as the evaporation pressure and the superheating temperature was taken into account. By appropriately selecting the working fluid and the Rankine cycle operation conditions the overall plant efficiency was improved by 5.52% and fuel consumption was reduced by 12.69%.

  19. DETERMINING HEATING RATES IN RECONNECTION FORMED FLARE LOOPS OF THE M8.0 FLARE ON 2005 MAY 13

    Energy Technology Data Exchange (ETDEWEB)

    Liu Wenjuan; Qiu Jiong; Longcope, Dana W. [Department of Physics, Montana State University, Bozeman, MT 59717-3840 (United States); Caspi, Amir [Laboratory for Atmospheric and Space Physics, University of Colorado, Boulder, CO 80303 (United States)

    2013-06-20

    We analyze and model an M8.0 flare on 2005 May 13 observed by the Transition Region and Coronal Explorer and the Reuven Ramaty High Energy Solar Spectroscopic Imager (RHESSI) to determine the energy release rate from magnetic reconnection that forms and heats numerous flare loops. The flare exhibits two ribbons in UV 1600 A emission. Analysis shows that the UV light curve at each flaring pixel rises impulsively within a few minutes, and decays slowly with a timescale longer than 10 minutes. Since the lower atmosphere (the transition region and chromosphere) responds to energy deposit nearly instantaneously, the rapid UV brightening is thought to reflect the energy release process in the newly formed flare loop rooted at the footpoint. In this paper, we utilize the spatially resolved (down to 1'') UV light curves and the thick-target hard X-ray emission to construct heating functions of a few thousand flare loops anchored at the UV footpoints, and compute plasma evolution in these loops using the enthalpy-based thermal evolution of loops model. The modeled coronal temperatures and densities of these flare loops are then used to calculate coronal radiation. The computed soft X-ray spectra and light curves compare favorably with those observed by RHESSI and by the Geostationary Operational Environmental Satellite X-ray Sensor. The time-dependent transition region differential emission measure for each loop during its decay phase is also computed with a simplified model and used to calculate the optically thin C IV line emission, which dominates the UV 1600 A bandpass during the flare. The computed C IV line emission decays at the same rate as observed. This study presents a method to constrain heating of reconnection-formed flare loops using all available observables independently, and provides insight into the physics of energy release and plasma heating during the flare. With this method, the lower limit of the total energy used to heat the flare loops in

  20. Proceedings of the 4th international conference on heat exchangers boilers and pressure vessels

    International Nuclear Information System (INIS)

    1999-01-01

    The conference discusses the following issues: pollution control for thermal units in the Egyptian industry; burnup calculations for ETRR-1 and ETRR-2 reactors; environmental impacts; heat exchangers; determination of economic life of marine power plant; psa study of ETRR-2 gadolinium injection system