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Sample records for high heat capacity

  1. Reassembling and testing of a high-precision heat capacity drop calorimeter. Heat capacity of some polyphenyls at T = 298.15 K

    Energy Technology Data Exchange (ETDEWEB)

    Santos, Luis M.N.B.F., E-mail: lbsantos@fc.up.pt [Centro de Investigacao em Quimica, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Rocha, Marisa A.A.; Rodrigues, Ana S.M.C. [Centro de Investigacao em Quimica, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal); Stejfa, Vojtech; Fulem, Michal [Department of Physical Chemistry, Institute of Chemical Technology, Technicka 5, CZ-166 28 Prague 6 (Czech Republic); Bastos, Margarida [Centro de Investigacao em Quimica, Departamento de Quimica e Bioquimica, Faculdade de Ciencias, Universidade do Porto, Rua do Campo Alegre, 687, 4169-007 Porto (Portugal)

    2011-12-15

    Graphical abstract: Highlights: > We present the reassembling, improvement and testing of a high-precision C{sub p} drop calorimeter. > The apparatus was tested, using benzoic acid and hexafluorobenzene. > The high sensitivity of the apparatus is comparable to the one obtained in adiabatic calorimetry. > Heat capacities at T = 298.15 K of some polyphenyls were measured. > Subtle heat capacity differences among position isomers (ortho, meta, para) were detected. - Abstract: The description of the reassembling and testing of a twin heat conduction, high-precision, drop microcalorimeter for the measurement of heat capacities of small samples are presented. The apparatus, originally developed and used at the Thermochemistry Laboratory, Lund, Sweden, has now been reassembled and modernized, with changes being made as regarding temperature sensors, electronics and data acquisition system. The apparatus was thereafter thoroughly tested, using benzoic acid and hexafluorobenzene as test substances. The accuracy of the C{sub p,m}{sup 0} (298.15 K) data obtained with this apparatus is comparable to that achieved by high-precision adiabatic calorimetry. Here we also present the results of heat capacity measurements on of some polyphenyls (1,2,3-triphenylbenzene, 1,3,5-triphenylbenzene, p-terphenyl, m-terphenyl, o-terphenyl, p-quaterphenyl) at T = 298.15 K, measured with the renewed high precision heat capacity drop calorimeter system. The high resolution and accuracy of the obtained heat capacity data enabled differentiation among the ortho-, meta-, and para-phenyl isomers.

  2. Heat capacity of iron, aluminum, and chromium vanadates at high temperatures

    Energy Technology Data Exchange (ETDEWEB)

    Cheshnitskii, S.M.; Fotiev, A.A.; Ignashin, V.P.; Kesler, Y.A.

    1985-09-01

    The thermodynamic characteristics of compounds participating in the processing of vanadium-containing raw materials have not been sufficiently investigated. In this paper the authors report on measurements of the heat capacities of the compounds FeVO/sub 4/, CrVO/sub 4/, AIVO/sub 4/, Fe/sub 2/V/sub 4/O/sub 13/ and FeCr(VO/sub 4/)/sub 2/ at high temperatures. The obtained experimental data on the high-temperature heat capacity of iron, aluminum, and chromium vanadates makes it possible to calculate the thermodynamic functions of these compounds at high temperatures.

  3. High temperature heat capacities and electrical conductivities of boron carbides

    International Nuclear Information System (INIS)

    Matsui, Tsuneo; Arita, Yuri; Naito, Keiji; Imai, Hisashi

    1991-01-01

    The heat capacities and the electrical conductivities of B x C(x=3, 4, 5) were measured by means of direct heating pulse calorimetry in the temperature range from 300 to 1500 K. The heat capacities of B x C increased with increasing x value. This increase in the heat capacity is probably related to the change of the lattice vibration mode originated from the reduction of the stiffness of the intericosahedral chain accompanied with a change from C-B-C to C-B-B chains. A linear relationship between the logarithm of σT (σ is the electrical conductivity and T is the absolute temperature) of B x C and the reciprocal temperature was observed, indicating the presence of small polaron hopping as the predominant conduction mechanism. The electrical conductivity of B x C also increased with increasing x value (from 4 to 5) due to an increase of the polaron hopping of holes between carbon atoms at geometrically nonequivalent sites, since these nonequivalent sites of carbon atoms were considered to increase in either B 11 C icosahedra or in icosahedral chains with increasing x. The electrical conductivity of B 3 C was higher than that of B 4 C, which is probably due to the precipitation of high-conducting carbon. The thermal conductivity and the thermodynamic quantities of B 4 C were also determined precisely from the heat capacity value. (orig.)

  4. Performance of heat engines with non-zero heat capacity

    International Nuclear Information System (INIS)

    Odes, Ron; Kribus, Abraham

    2013-01-01

    Highlights: ► Finite heat capacity is a second irreversibility mechanism in addition to thermal resistance. ► Heat capacity introduces thermal transients and reverse heat flow. ► Engine maximum power and efficiency are lower for finite heat capacity. ► Implementing the optimal engine cycle requires active control. - Abstract: The performance of a heat engine is analyzed subject to two types of irreversibility: a non-zero heat capacity, together with the more common finite heat transfer rate between the engine and the external heat reservoirs. The heat capacity represents an engine body that undergoes significant temperature variations during the engine cycle. An option to cut off the heat exchange between the engine and the external surrounding for part of the engine cycle is also explored. A variational approach was taken to find the engine’s internal temperature profile (which defines the internal thermodynamic cycle) that would produce maximum power. The maximum power is shown to be lower than the case of zero heat capacity, due to a loss of heat that is stored in the engine body and then lost, bypassing the thermodynamic cycle. The maximum efficiency and the efficiency at maximum power are also lower than the zero heat capacity case. Similar to the Curzon–Ahlborn analysis, power can be traded for increased efficiency, but for high heat capacity, the range of efficiency that is available for such a trade is diminished. Isolating the engine during part of the cycle reduces maximum power, but the efficiency at maximum power and the maximum efficiency are improved, due to better exploitation of heat stored in the engine body. This might be useful for real engines that are limited by the internal energy change during a single engine cycle or by the operating frequency, leading to a broader power–efficiency curve.

  5. Space qualification of high capacity grooved heat pipes

    Energy Technology Data Exchange (ETDEWEB)

    Dubois, M; Mullender, B; Druart, J [SABCA, Societe Anomyme Belgel de Construction Aeronautique (Belgium); Supper, W; Beddows, A [ESTEC-The (Netherlands)

    1997-12-31

    Based on the thermal requirements of the future telecommunication satellites, the development of a High Capacity Grooved Heat Pipe (HPG), was contracted by ESA to SABCA leading to an aluminium extruded heat pipe (outer diameter of 25 mm) based on a multi re-entrant grooves design. After an intensive acceptance test campaign whose results showed a good confidence in the design and the fulfillment of the required specifications of heat transport and on tilt capability (experimental maximum heat transport capability of 1500 Watt metres for a vapour temperature of 20 deg C), similar heat pipes have been developed with various outer diameters (11 mm, 15 mm and 20 mm) and with various shapes (circular outer shapes, integrated saddles). Several of these heat pipes were tested during two parabolic flight campaigns, by varying the heat loads during the micro-gravity periods. This HGP heat pipe family is now being submitted to a space qualification program according to ESA standards (ESA PSS-49), both in straight and bent configuration. Within this qualification, the heat pipes are submitted to an extended test campaign including environmental (random/sinus vibration, constant acceleration) and thermal tests (thermal performance, thermal cycle, thermal soak, ageing). (authors) 9 refs.

  6. Space qualification of high capacity grooved heat pipes

    Energy Technology Data Exchange (ETDEWEB)

    Dubois, M.; Mullender, B.; Druart, J. [SABCA, Societe Anomyme Belgel de Construction Aeronautique (Belgium); Supper, W.; Beddows, A. [ESTEC-The (Netherlands)

    1996-12-31

    Based on the thermal requirements of the future telecommunication satellites, the development of a High Capacity Grooved Heat Pipe (HPG), was contracted by ESA to SABCA leading to an aluminium extruded heat pipe (outer diameter of 25 mm) based on a multi re-entrant grooves design. After an intensive acceptance test campaign whose results showed a good confidence in the design and the fulfillment of the required specifications of heat transport and on tilt capability (experimental maximum heat transport capability of 1500 Watt metres for a vapour temperature of 20 deg C), similar heat pipes have been developed with various outer diameters (11 mm, 15 mm and 20 mm) and with various shapes (circular outer shapes, integrated saddles). Several of these heat pipes were tested during two parabolic flight campaigns, by varying the heat loads during the micro-gravity periods. This HGP heat pipe family is now being submitted to a space qualification program according to ESA standards (ESA PSS-49), both in straight and bent configuration. Within this qualification, the heat pipes are submitted to an extended test campaign including environmental (random/sinus vibration, constant acceleration) and thermal tests (thermal performance, thermal cycle, thermal soak, ageing). (authors) 9 refs.

  7. High energy bursts from a solid state laser operated in the heat capacity limited regime

    Science.gov (United States)

    Albrecht, G.; George, E.V.; Krupke, W.F.; Sooy, W.; Sutton, S.B.

    1996-06-11

    High energy bursts are produced from a solid state laser operated in a heat capacity limited regime. Instead of cooling the laser, the active medium is thermally well isolated. As a result, the active medium will heat up until it reaches some maximum acceptable temperature. The waste heat is stored in the active medium itself. Therefore, the amount of energy the laser can put out during operation is proportional to its mass, the heat capacity of the active medium, and the temperature difference over which it is being operated. The high energy burst capacity of a heat capacity operated solid state laser, together with the absence of a heavy, power consuming steady state cooling system for the active medium, will make a variety of applications possible. Alternately, cooling takes place during a separate sequence when the laser is not operating. Industrial applications include new material working processes. 5 figs.

  8. Heat Capacity Analysis Report

    International Nuclear Information System (INIS)

    Findikakis, A.

    2004-01-01

    The purpose of this report is to provide heat capacity values for the host and surrounding rock layers for the waste repository at Yucca Mountain. The heat capacity representations provided by this analysis are used in unsaturated zone (UZ) flow, transport, and coupled processes numerical modeling activities, and in thermal analyses as part of the design of the repository to support the license application. Among the reports that use the heat capacity values estimated in this report are the ''Multiscale Thermohydrologic Model'' report, the ''Drift Degradation Analysis'' report, the ''Ventilation Model and Analysis Report, the Igneous Intrusion Impacts on Waste Packages and Waste Forms'' report, the ''Dike/Drift Interactions report, the Drift-Scale Coupled Processes (DST and TH Seepage) Models'' report, and the ''In-Drift Natural Convection and Condensation'' report. The specific objective of this study is to determine the rock-grain and rock-mass heat capacities for the geologic stratigraphy identified in the ''Mineralogic Model (MM3.0) Report'' (BSC 2004 [DIRS 170031], Table 1-1). This report provides estimates of the heat capacity for all stratigraphic layers except the Paleozoic, for which the mineralogic abundance data required to estimate the heat capacity are not available. The temperature range of interest in this analysis is 25 C to 325 C. This interval is broken into three separate temperature sub-intervals: 25 C to 95 C, 95 C to 114 C, and 114 C to 325 C, which correspond to the preboiling, trans-boiling, and postboiling regimes. Heat capacity is defined as the amount of energy required to raise the temperature of a unit mass of material by one degree (Nimick and Connolly 1991 [DIRS 100690], p. 5). The rock-grain heat capacity is defined as the heat capacity of the rock solids (minerals), and does not include the effect of water that exists in the rock pores. By comparison, the rock-mass heat capacity considers the heat capacity of both solids and pore

  9. Densities, viscosities, and isobaric heat capacities of the system (1-butanol + cyclohexane) at high pressures

    International Nuclear Information System (INIS)

    Torín-Ollarves, Geraldine A.; Martín, M. Carmen; Chamorro, César R.; Segovia, José J.

    2014-01-01

    Highlights: • The densities of cyclohexane and its mixtures with 1-butanol were measured. • The excess molar volumes were calculated and correlated. • The viscosities were measured at atmospheric pressure. • The isobaric heat capacities were measured at p = (0.1 to 25) MPa at T = (293.15 and 313.15) K. • A positive deviation from the ideal behavior is observed. - Abstract: The cyclohexane and the system of 1-butanol + cyclohexane have been characterized using densities, viscosities and isobaric heat capacities measurements. For that, the densities were measured in a high-pressure vibrating tube densimeter at five temperatures from (293.15 to 333.15) K and pressures up to 100 MPa. The measurements were correlated with the empirical Tamman–Tait equation. Moreover, the isobaric heat capacities of the binary system were measured in a high-pressure automated flow calorimeter at T = (293.15 and 313.15) K and pressures up to 25 MPa for pure cyclohexane and in admixture with 1-butanol. The excess molar heat capacities were assessed for the mixture and a positive deviation from the ideality was obtained, except for a small part in the region rich in alkanol. The viscosity measurements were carried out, at the calorimeter conditions, for correcting the experimental values of isobaric heat capacities due to friction along the tube. The viscosity was measured at atmospheric pressure in a Stabinger Anton Paar SVM 3000 viscometer in the temperature range of (293.15 to 333.15) K for cyclohexane and the mixtures. At high pressure, the viscosities were estimated using Lucas method

  10. The capacity credit of micro-combined heat and power

    International Nuclear Information System (INIS)

    Hawkes, A.D.; Leach, M.A.

    2008-01-01

    This article is concerned with development of a methodology to determine the capacity credit of micro-combined heat and power (micro-CHP), and application of the method for the UK. Capacity credit is an important parameter in electricity system planning because it measures the amount of conventional generation that would be displaced by an alternative technology. Firstly, a mathematical formulation is presented. Capacity credit is then calculated for three types of micro-CHP units-Stirling engine, internal combustion engine, and fuel cell systems-operating under various control strategies. It is found that low heat-to-power ratio fuel cell technologies achieve the highest capacity credit of approximately 85% for a 1.1 GW penetration when a heat-led control strategy is applied. Higher heat-to-power ratio Stirling engine technology achieves approximately 33% capacity credit for heat-led operation. Low heat-to-power ratio technologies achieve higher capacity credit because they are able to continue operating even when heat demand is relatively low. Capacity credit diminishes as penetration of the technology increases. Overall, the high capacity credit of micro-CHP contributes to the viewpoint that the technology can help meet a number of economic and environmental energy policy aims

  11. MEASUREMENT OF SPECIFIC HEAT CAPACITY OF SALTSTONE

    International Nuclear Information System (INIS)

    Harbour, J.; Williams, V.

    2008-01-01

    result in a larger temperature increase in the Saltstone vaults during the curing period. The initial temperature of the Saltstone mixes in the Saltstone Production Facility (SPF) can be predicted using the specific heat capacities of Decontaminated Salt Solutions (DSS), the specific heat capacities of cementitious materials, and the initial temperatures of the DSS and the premix. This initial mix temperature is dominated by the DSS temperature due to its high heat capacity relative to the cementitious materials. Therefore, controlling the initial temperature of the DSS to lower temperatures will lead to lower maximum temperatures in the vault for a given batch of Saltstone

  12. MEASUREMENT OF SPECIFIC HEAT CAPACITY OF SALTSTONE

    Energy Technology Data Exchange (ETDEWEB)

    Harbour, J; Vickie Williams, V

    2008-09-29

    in turn will result in a larger temperature increase in the Saltstone vaults during the curing period. The initial temperature of the Saltstone mixes in the Saltstone Production Facility (SPF) can be predicted using the specific heat capacities of Decontaminated Salt Solutions (DSS), the specific heat capacities of cementitious materials, and the initial temperatures of the DSS and the premix. This initial mix temperature is dominated by the DSS temperature due to its high heat capacity relative to the cementitious materials. Therefore, controlling the initial temperature of the DSS to lower temperatures will lead to lower maximum temperatures in the vault for a given batch of Saltstone.

  13. Experimental investigation of a PCM-HP heat sink on its thermal performance and anti-thermal-shock capacity for high-power LEDs

    International Nuclear Information System (INIS)

    Wu, Yuxuan; Tang, Yong; Li, Zongtao; Ding, Xinrui; Yuan, Wei; Zhao, Xuezhi; Yu, Binhai

    2016-01-01

    Highlights: • A phase-change material (PCM) base heat pipe heat sink (PCM-HP heat sink) is designed. • The PCM-HP heat sink can significantly lower the LED heating rate and temperature. • The PCM-HP heat sink achieves a best anti-thermal-shock capacity in LED cyclic working modes. - Abstract: High-power LEDs demonstrate a number of benefits compared with conventional incandescent lamps and fluorescent lamps, including a longer lifetime, higher brightness and lower power consumption. However, owing to their severe high heat flux, it is difficult to develop effective thermal management of high-power LEDs, especially under cyclic working modes, which cause serious periodic thermal stress and limit further development. Focusing on the above problem, this paper designed a phase-change material (PCM) base heat pipe heat sink (PCM-HP heat sink) that consists of a PCM base, adapter plate, heat pipe and finned radiator. Different parameters, such as three types of interior materials to fill the heat sink, three LED power inputs and eight LED cyclic working modes, were separately studied to investigate the thermal performance and anti-thermal-shock capacity of the PCM-HP heat sink. The results show that the PCM-HP heat sink possesses remarkable thermal performance owing to the reduction of the LED heating rate and peak temperature. More importantly, an excellent anti-thermal-shock capacity of the PCM-HP heat sink is also demonstrated when applied in LED cyclic working modes, and this capacity demonstrates the best range.

  14. High-performance heat pipes for heat recovery applications

    Science.gov (United States)

    Saaski, E. W.; Hartl, J. H.

    1980-01-01

    Methods to improve the performance of reflux heat pipes for heat recovery applications were examined both analytically and experimentally. Various models for the estimation of reflux heat pipe transport capacity were surveyed in the literature and compared with experimental data. A high transport capacity reflux heat pipe was developed that provides up to a factor of 10 capacity improvement over conventional open tube designs; analytical models were developed for this device and incorporated into a computer program HPIPE. Good agreement of the model predictions with data for R-11 and benzene reflux heat pipes was obtained.

  15. Experimental study on heat capacity of paraffin/water phase change emulsion

    International Nuclear Information System (INIS)

    Huang, L.; Noeres, P.; Petermann, M.; Doetsch, C.

    2010-01-01

    A paraffin/water phase change emulsion is a multifunctional fluid in which fine paraffin droplets are dispersed in water by a surfactant. This paper presents an experimental study on the heat capacity of an emulsion containing 30 wt.% paraffin in a test rig. The results show that the heat capacity of the emulsion consists of the sensible heat capacity of water and that of the paraffin as well as the latent heat capacity of the paraffin during the phase transition solid-liquid. The emulsion is an attractive alternative to chilled water for comfort cooling applications, because it has a heat capacity of 50 kJ/kg from 5 to 11 deg. C, which is two times as high as that of water in the same temperature range.

  16. Anomalous heat capacity of nanoparticles

    International Nuclear Information System (INIS)

    Likhachev, V.N.; Vinogradov, G.A.; Alymov, M.I.

    2006-01-01

    The heat capacity of nanosized particles exceeds (from few to tenth percents) the same values of the corresponding bulk materials, and this difference increases with the diminishing of the sizes. In the present Letter we give an explanation of this phenomenon on an example of a nanocrystal with simple cubic lattice and an arbitrary shape. The simplest harmonic interaction potential of the nearest neighbors is used. A qualitative agreement with experimental data is obtained. The decisive role is attributed to the choice of boundary conditions: free boundaries provide the 'softening' of vibrational spectrum thus giving larger contribution to the heat capacity. The increase in heat capacity depends on the particle size, shape and sample perfection

  17. Transient heat transfer to laminar flow from a flat plate with heat capacity

    International Nuclear Information System (INIS)

    Hanawa, Juichi

    1975-01-01

    As the most basic problem in transient heat transfer, a plate with heat capacity was studied, which is placed in uniform laminar flow in parallel with it, is initially at the same temperature as that of the fluid, and then abruptly is given a specific heating value. The equation of transient heat transfer in this case was solved by numerical calculation. The following matters were revealed. (1) The equation was able to be solved by the application of Laplace transformation and numerical inverse transformation. (2) Wall temperature when the heat capacity of a plate was zero initially agreed well with heat conduction solution. With increase of the heat capacity, the delay in wall temperature rise was increased. (3) Heat transfer rate in case of the heat capacity of zero initially agreed well with the heat-conduction solution. With increase of the heat capacity, the Nusselt number increased. (4) Temperature distribution in case of the heat capacity of zero initially agreed well with the heat-conduction solution. (Mori, K.)

  18. Heat capacity of poly(lactic acid)

    International Nuclear Information System (INIS)

    Pyda, M.; Bopp, R.C.; Wunderlich, B.

    2004-01-01

    The heat capacity of poly(lactic acid) (PLA) is reported from T=(5 to 600) K as obtained by differential scanning calorimetry (d.s.c.) and adiabatic calorimetry. The heat capacity of solid PLA is linked to its group vibrational spectrum and the skeletal vibrations, the latter being described by a Tarasov equation with Θ 1 =574 K, Θ 2 =Θ 3 =52 K, and nine skeletal vibrations. The calculated and experimental heat capacities agree to ±3% between T=(5 and 300) K. The experimental heat capacity of liquid PLA can be expressed by C p (liquid)=(120.17+0.076T) J · K -1 · mol -1 and has been compared to the ATHAS Data Bank, using contributions of other polymers with the same constituent groups. The glass transition temperature of amorphous PLA occurs at T=332.5 K with a change in heat capacity of 43.8 J · K -1 · mol -1 . Depending on thermal history, semi-crystalline PLA has a melting endotherm between T=(418 and 432) K with variable heats of fusion. For 100% crystalline PLA, the heat of fusion is estimated to be (6.55 ± 0.02) kJ · mol -1 at T=480 K. With these results, the enthalpy, entropy, and Gibbs function of crystalline and amorphous PLA were obtained. For semi-crystalline samples, one can check changes of crystallinity with temperature and judge the presence of rigid-amorphous fractions

  19. Highly macroscopically degenerated single-point ground states as source of specific heat capacity anomalies in magnetic frustrated systems

    Science.gov (United States)

    Jurčišinová, E.; Jurčišin, M.

    2018-04-01

    Anomalies of the specific heat capacity are investigated in the framework of the exactly solvable antiferromagnetic spin- 1 / 2 Ising model in the external magnetic field on the geometrically frustrated tetrahedron recursive lattice. It is shown that the Schottky-type anomaly in the behavior of the specific heat capacity is related to the existence of unique highly macroscopically degenerated single-point ground states which are formed on the borders between neighboring plateau-like ground states. It is also shown that the very existence of these single-point ground states with large residual entropies predicts the appearance of another anomaly in the behavior of the specific heat capacity for low temperatures, namely, the field-induced double-peak structure, which exists, and should be observed experimentally, along with the Schottky-type anomaly in various frustrated magnetic system.

  20. Parametric Study on the Dynamic Heat Storage Capacity of Building Elements

    DEFF Research Database (Denmark)

    Artmann, Nikolai; Manz, H.; Heiselberg, Per

    2007-01-01

    as their interrelation. The potential of increasing thermal mass by using phase change materials (PCM) was estimated assuming increased thermal capacity. The results show a significant impact of the heat transfer coefficient on heat storage capacity, especially for thick, thermally heavy elements. The storage capacity...... of onedimensional heat conduction in a slab with convective boundary condition was applied to quantify the dynamic heat storage capacity of a particular building element. The impact of different parameters, such as slab thickness, material properties and the heat transfer coefficient was investigated, as well......In modern, extensively glazed office buildings, due to high solar and internal loads and increased comfort expectations, air conditioning systems are often used even in moderate and cold climates. Particularly in this case, passive cooling by night-time ventilation seems to offer considerable...

  1. Heat capacity characterization at phase transition temperature of Agl superionic

    International Nuclear Information System (INIS)

    Widowati, Arie

    2000-01-01

    The phase transition of Agl superionic conductor was investigated by calorometric. A single phase transition was found at (153±5) o C which corresponds to the α - β transition. Calorimetric measurement showed an anomalously high heat capacity with a large discontinues change in the Arrhenius plot, was found above the transition temperature of β - α phase. The maximum heat capacity was found to be ±19.7 cal/gmol. Key words : superionic conductor, thermal capacity

  2. Heat capacity measurement of CeNbO4(s)

    International Nuclear Information System (INIS)

    Bhojane, S.M.; Kulkarni, Jayanthi; Kulkarni, S.G.

    2012-01-01

    Molar heat capacity of CeNbO 4 (s) was determined using differential scanning calorimeter in the temperature range of 550 to 900 K. The molar heat capacity values were least squares analysed and the dependence of molar heat capacity with temperature for CeNbO 4 (s) can be given as, J K -1 mol -1 = 94.7320 + 0.0852T-1.6073 x 10 6 T -2 (550≤T(K)≤900) Cerium is commonly used as an inactive analogue to plutonium; also it is an important fission product with moderate yield. Various Nb alloys are used as cladding material in nuclear industry. Hosts of thermodynamic data are needed to understand the various phenomena that occur in a nuclear reactor. In the present study, the molar heat capacity of CeNbO 4 (s) has been determined using high temperature differential scanning calorimeter in temperature range 550 to 900 K. This is one of the important compounds in the ternary system of Ce-Nb-O

  3. Peculiar features of heat capacity for Cu and Ni nanoclusters

    International Nuclear Information System (INIS)

    Gafner, S. L.; Redel, L. V.; Gafner, Yu. Ya.; Samsonov, V. M.

    2011-01-01

    The heat capacity of copper and nickel clusters (from 2 to 6 nm in diameter) was investigated in the temperature range 200–800 K using molecular dynamics method and a modified tight-binding potential. The simulation results demonstrate a very good agreement with the available experimental data at T = 200 K and a fairy good agreement at higher temperatures. A number of regular trends are revealed in computer experiments which agree with the corresponding theoretical predictions. A conclusion is made that in the case of single free clusters the heat capacity may exceed the capacity of the corresponding bulk material. It is found that at 200 K, the copper nanocluster (D = 6 nm) heat capacity is higher by 10% and for nickel cluster by 13%. The difference diminishes with increasing the nanoparticles size proportionally to the relative number of surface atoms. A conclusion is made that very high values of the nanostructure heat capacity observed in laboratory experiments should not be attributed to free clusters, i.e., the effect in question is caused by other reasons.

  4. Heat capacity and thermal expansion of the itinerant helimagnet MnSi

    International Nuclear Information System (INIS)

    Stishov, S M; Petrova, A E; Khasanov, S; Panova, G Kh; Shikov, A A; Lashley, J C; Wu, D; Lograsso, T A

    2008-01-01

    The heat capacity and thermal expansion of a high quality single crystal of MnSi were measured at ambient pressure at zero and high magnetic fields. The calculated magnetic entropy change in the temperature range 0-30 K is less than 0.1R, a low value that emphasizes the itinerant nature of magnetism in MnSi. A linear temperature term dominates the thermal expansion coefficient in the range 30-150 K, which correlates with an enhancement of the linear electronic term in the heat capacity. A surprising similarity among the variations of the heat capacity, thermal expansion coefficient and temperature derivative of the resistivity is observed through the phase transition in MnSi. Specific forms of the heat capacity, thermal expansion coefficient and temperature derivative of resistivity at the phase transition to a helical magnetic state near 29 K are interpreted as the combination of sharp first-order features and broad peaks or shallow valleys of as yet unknown origin. The appearance of these broad satellites probably hints at a frustrated magnetic state slightly above the transition temperature in MnSi

  5. The Heat Capacity of Ideal Gases

    Science.gov (United States)

    Scott, Robert L.

    2006-01-01

    The heat capacity of an ideal gas has been shown to be calculable directly by statistical mechanics if the energies of the quantum states are known. However, unless one makes careful calculations, it is not easy for a student to understand the qualitative results. Why there are maxima (and occasionally minima) in heat capacity-temperature curves…

  6. Forecasting of heat capacity of molecular inorganic liquids

    International Nuclear Information System (INIS)

    Sladkov, I.B.; Neganov, O.S.

    1992-01-01

    On the basis of analysis of experimental material on heat capacity of liquids, covering 350 molecular inorganic compounds, atomic parts of heat capacity for 58 elements of the Periodic system were obtained. Data on the accuracy of heat capacity calculation by the Neumann-Kopp rule using the recommended atomic parts C p are presented. For the Kelli rule it is assertained that the factor of proportiomality between heat capacity and the number of atoms in compound molecule in the general case depends on the type of anion and compound coordination. The Neumann-Kopp-Kelli rules provide a satisfactory accuracy of prediction

  7. Heat capacity of xenon adsorbed in nanobundle grooves

    International Nuclear Information System (INIS)

    Chishko, K.A.; Sokolova, E.S.

    2016-01-01

    A model of one-dimensional real gas under external transverse force field is applied to interpret the experimentally observed thermodynamical properties of xenon deposited into groves on the surface of carbon nanobundles. This non-ideal gas model with pair interaction is not quite adequate to describe the dense adsorbates (especially at low temperature limit), but it makes possible to take into account easily the particle exchange between 1D adsorbate and 3D atmosphere which becomes an essential factor since intermediate (for xenon - of order 35 K) up to high (approx 100 K) temperatures. In this paper we treat the 1D real gas with only Lennard-Jones pair interaction, but at presence of exact equilibrium conditions on the atom numbers between low-dimensional adsorbate and three-dimensional atmosphere of the experimental cell. The low-temperature branch of the heat capacity has been fitted separately within the elastic atomic chain model to get the best agreement between theory and experiment in as wide as possible region just from zero temperature. The gas approximation is introduced from the temperatures where the chain heat capacity tends definitely to 1D equipartition law. In this case the principal parameters for both models can be chosen in such a way that the heat capacity C(T) of the chain goes continuously into the corresponding curve of the gas approximation. So, it seems to be expected that adequate interpretation for temperature dependences of the atomic adsorbate heat capacity can be obtained through a reasonable combination of 1D gas and phonon approaches. The principal parameters of the gas approximation (such a desorption energy) found from the fitting between theory and experiment for xenon heat capacity are in good agreement with corresponding data known in literature.

  8. Gaseous phase heat capacity of benzoic acid

    NARCIS (Netherlands)

    Santos, L.M.N.B.F.; Alves da Rocha, M.A.; Gomes, L.R.; Schröder, B.; Coutinho, J.A.P.

    2010-01-01

    The gaseous phase heat capacity of benzoic acid (BA) was proven using the experimental technique called the "in vacuum sublimation/vaporization Calvet microcalorimetry drop method". To overcome known experimental shortfalls, the gaseous phase heat capacity of BA monomer was estimated by ab initio

  9. Cooling and Heating Season Impacts of Right-Sizing of Fixed- and Variable-Capacity Heat Pumps With Attic and Indoor Ductwork

    Energy Technology Data Exchange (ETDEWEB)

    Cummings, James [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States); Withers, Charles [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States); Kono, Jamie [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States)

    2015-06-01

    A new generation of central, ducted variable-capacity heat pump systems has come on the market, promising very high cooling and heating efficiency. They are controlled differently than standard fixed-capacity systems. Instead of cycling on at full capacity and then cycling off when the thermostat is satisfied, they vary their cooling and heating output over a wide range (approximately 40% - 118% of nominal full capacity), thus staying 'on' for 60% - 100% more hours per day compared to fixed -capacity systems. Experiments in this research examined the performance of 2-ton and 3-ton fixed- and variable-capacity systems and the impacts of system oversizing.

  10. Heat capacity and thermal expansion of the itinerant helimagnet MnSi.

    Science.gov (United States)

    Stishov, S M; Petrova, A E; Khasanov, S; Kh Panova, G; Shikov, A A; Lashley, J C; Wu, D; Lograsso, T A

    2008-06-11

    The heat capacity and thermal expansion of a high quality single crystal of MnSi were measured at ambient pressure at zero and high magnetic fields. The calculated magnetic entropy change in the temperature range 0-30 K is less than 0.1R, a low value that emphasizes the itinerant nature of magnetism in MnSi. A linear temperature term dominates the thermal expansion coefficient in the range 30-150 K, which correlates with an enhancement of the linear electronic term in the heat capacity. A surprising similarity among the variations of the heat capacity, thermal expansion coefficient and temperature derivative of the resistivity is observed through the phase transition in MnSi. Specific forms of the heat capacity, thermal expansion coefficient and temperature derivative of resistivity at the phase transition to a helical magnetic state near 29 K are interpreted as the combination of sharp first-order features and broad peaks or shallow valleys of as yet unknown origin. The appearance of these broad satellites probably hints at a frustrated magnetic state slightly above the transition temperature in MnSi.

  11. Heat capacity of solid parahydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Bagatskij, M I; Minchina, I Ya; Manzhelij, V G [AN Ukrainskoj SSR, Kharkov. Fiziko-Tekhnicheskij Inst. Nizkikh Temperatur

    1984-10-01

    A vacuum adiabatic calorimeter has been developed to investigate cryocrystals and their solutions in the range 0.4-300 K. Heat capacity of hydrogen with the orthomodification concentration 5 x 10/sup -3/ at.% between 0.5 and 8 K has been investigated. The limiting Debye temperature at T ..-->.. 0 has been obtained: (THETA/sub 0/=118.5 +- 0.5 K). It has been shown that heat capacity of solid parahydrogen, as that of other cryocrystals with the central interaction and closely packed lattices (/sup 4/He, Ne, Ar, Kr, Xe), low temperatures is given by the universal relation proposed by Barron and Morrison Csub(V) AT/sup 3/(1+..cap alpha../sub 1/(T/THETA/sub 0/)/sup 2/ + ..cap alpha../sub 2/(T/THETA/sub 0/)/sup 4/ ...). The effect of the sample time prehistory on the experimental heat capacity values of hydrogen with g.21 at.% orthomodification has been studied, and the times during which configurational equilibration in this solution is reached have been estimated.

  12. Low-temperature heat capacity of molybdenum borides

    International Nuclear Information System (INIS)

    Bolgar, A.S.; Klinder, A.V.; Novoseletskaya, L.M.; Turov, V.P.; Klochkov, L.A.; Lyashchenko, A.B.

    1988-01-01

    Heat capacity of molybdenum borides Mo 2 B, MoB, Mo 2 B 5 is studied for the first time in the 60-300 K range using the adiabatic method. Standard (at 298.15 K) thermodynamic functions (enthalpy, heat capacity, entropy, reduced Gibbs energy) of molybdenum borides are calculated

  13. Free energy and heat capacity

    International Nuclear Information System (INIS)

    Kurata, M.; Devanathan, R.

    2015-01-01

    Free energy and heat capacity of actinide elements and compounds are important properties for the evaluation of the safety and reliable performance of nuclear fuel. They are essential inputs for models that describe complex phenomena that govern the behaviour of actinide compounds during nuclear fuels fabrication and irradiation. This chapter introduces various experimental methods to measure free energy and heat capacity to serve as inputs for models and to validate computer simulations. This is followed by a discussion of computer simulation of these properties, and recent simulations of thermophysical properties of nuclear fuel are briefly reviewed. (authors)

  14. Relationship between low-temperature boson heat capacity peak and high-temperature shear modulus relaxation in a metallic glass

    International Nuclear Information System (INIS)

    Vasiliev, A. N.; Voloshok, T. N.; Granato, A. V.; Joncich, D. M.; Mitrofanov, Yu. P.; Khonik, V. A.

    2009-01-01

    Low-temperature (2 K≤T≤350 K) heat capacity and room-temperature shear modulus measurements (ν=1.4 MHz) have been performed on bulk Pd 41.25 Cu 41.25 P 17.5 in the initial glassy, relaxed glassy, and crystallized states. It has been found that the height of the low-temperature Boson heat capacity peak strongly correlates with the changes in the shear modulus upon high-temperature annealing. It is this behavior that was earlier predicted by the interstitialcy theory, according to which dumbbell interstitialcy defects are responsible for a number of thermodynamic and kinetic properties of crystalline, (supercooled) liquid, and solid glassy states.

  15. Prediction of Liquid Specific Heat Capacity of Food Lipids.

    Science.gov (United States)

    Zhu, Xiaoyi; Phinney, David M; Paluri, Sravanti; Heldman, Dennis R

    2018-04-01

    Specific heat capacity (c p ) is a temperature dependent physical property of foods. Lipid-being a macromolecular component of food-provides some fraction of the food's overall heat capacity. Fats/oils are complex chemicals that are generally defined by carbon length and degree of unsaturation. The objective of this investigation was to use advanced specific heat capacity measurement to determine the effect of fatty acid chemical structure on specific heat capacity of food lipids. In this investigation, the specific heat capacity of a series of triacylglycerols were measured to quantify the influence of fatty acid composition on specific heat capacity based on two parameters; the -average carbon number (C) and the average number of double bonds (U). A prediction model for specific heat capacity of food lipids as a function of C, U and temperature (T) has been developed. A multiple linear regression to the three-parameter model (R 2 = 0.87) provided a good fit to the experimental data. The prediction model was evaluated by comparison with previously published specific heat capacity values of vegetable oils. It was found that the model provided a 0.53% error, while three other models from the literature predicted c p values with 0.85% to 1.83% average relative deviation from experimental data. The outcomes from this research confirm that the thermophysical properties of fat present in foods are directly related to the physical chemical properties. The specific heat capacity of food products is widely used in process design. Improvements of current models to predict specific heat capacity of food products will assist in the development of efficient processes and in the control of food quality and safety. Furthermore, the understanding of how changes in chemical structure of macromolecular components of foods effect thermophysical properties may begin to allude to models that are not just empirical, but represent portions of the differences in chemistry. © 2018

  16. Heat capacity of ThO2

    International Nuclear Information System (INIS)

    Peng Shian

    1996-01-01

    The heat capacity C p of ThO 2 can be calculated as the phonon part of C p for other actinide dioxides used as fuel in nuclear reactors. Precise determination of the phonon part of C p of actinide dioxides is helpful to find out the contributions of other factors to C p . In this paper we have, through studying the heat capacity of ThO 2 , developed a general method applicable to the study of C p of other solids. In the developed method the three type -- different experimental measurements made on a solid-heat capacity, thermal expansion and Debye Waller factor -- can be brought together for comparison. The application of this method to the study of C p of ThO 2 has enabled us to propose a better description of C p of ThO 2 than the generally accepted expression

  17. Classical fluids of negative heat capacity

    Energy Technology Data Exchange (ETDEWEB)

    Landsberg, P.T. [Southampton Univ., (United Kingdom). Faculty of Mathematical Studies; Woodard, R.P. [Florida Univ., Gainesville, FL (United States). Dept. of Physics

    1992-06-01

    It is shown that new parameters X can be defined such that the heat capacity C{sub X} {equivalent_to} T({partial_derivative}S/{partial_derivative}T)X is negative, even when the canonical ensemble (i.e. at fixed T = ({partial_derivative}U/{partial_derivative}S) and Y {ne} X) is stable. As examples we treat black body radiation and general gas systems with nonsingular {kappa}{sub T}. For the case of a simple ideal gas we even exhibit an apparatus which enforces a constraint X(p,V) = const. that makes C{sub X} < 0. Since it is possible to invent constraints for which canonically stable systems have negative heat capacity we speculate that it may also be possible to infer the statistical mechanics of canonically unstable systems - for which even the traditional heat capacities are negative - by imposing constraints that stabilize the associated, inoncanonical ensembles.

  18. Classical fluids of negative heat capacity

    Energy Technology Data Exchange (ETDEWEB)

    Landsberg, P.T. (Southampton Univ., (United Kingdom). Faculty of Mathematical Studies); Woodard, R.P. (Florida Univ., Gainesville, FL (United States). Dept. of Physics)

    1992-06-01

    It is shown that new parameters X can be defined such that the heat capacity C{sub X} {equivalent to} T({partial derivative}S/{partial derivative}T)X is negative, even when the canonical ensemble (i.e. at fixed T = ({partial derivative}U/{partial derivative}S) and Y {ne} X) is stable. As examples we treat black body radiation and general gas systems with nonsingular {kappa}{sub T}. For the case of a simple ideal gas we even exhibit an apparatus which enforces a constraint X(p,V) = const. that makes C{sub X} < 0. Since it is possible to invent constraints for which canonically stable systems have negative heat capacity we speculate that it may also be possible to infer the statistical mechanics of canonically unstable systems - for which even the traditional heat capacities are negative - by imposing constraints that stabilize the associated, inoncanonical ensembles.

  19. Heat capacity for systems with excited-state quantum phase transitions

    Energy Technology Data Exchange (ETDEWEB)

    Cejnar, Pavel; Stránský, Pavel, E-mail: stransky@ipnp.troja.mff.cuni.cz

    2017-03-18

    Heat capacities of model systems with finite numbers of effective degrees of freedom are evaluated using canonical and microcanonical thermodynamics. Discrepancies between both approaches, which are observed even in the infinite-size limit, are particularly large in systems that exhibit an excited-state quantum phase transition. The corresponding irregularity of the spectrum generates a singularity in the microcanonical heat capacity and affects smoothly the canonical heat capacity. - Highlights: • Thermodynamics of systems with excited-state quantum phase transitions • ESQPT-generated singularities of the microcanonical heat capacity • Non-monotonous dependences of the canonical heat capacity • Discord between canonical and microcanonical pictures in the infinite-size limit.

  20. Cooling and Heating Season Impacts of Right-Sizing of Fixed- and Variable-Capacity Heat Pumps With Attic and Indoor Ductwork

    Energy Technology Data Exchange (ETDEWEB)

    Cummings, James [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States); Withers, Charles [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States); Kono, Jamie [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States)

    2015-06-24

    A new generation of full variable-capacity air-conditioning (A/C) and heat pump units has come on the market that promises to deliver very high cooling and heating efficiency. The units are controlled differently than standard single-capacity (fixed-capacity) systems. Instead of cycling on at full capacity and cycling off when the thermostat is satisfied, the new units can vary their capacity over a wide range (approximately 40%–118% of nominal full capacity) and stay on for 60%–100% more hours per day than the fixed-capacity systems depending on load-to-capacity ratios. Two-stage systems were not evaluated in this research effort.

  1. Determination of Heat Capacity of Yucca Mountain Stratigraphic Layers

    International Nuclear Information System (INIS)

    T. Hadgu; C. Lum; J.E. Bean

    2006-01-01

    The heat generated from the radioactive waste to be placed in the proposed geologic repository at Yucca Mountain, Nevada, will affect the thermal-hydrology of the Yucca Mountain stratigraphic layers. In order to assess the effect of the movement of repository heat into the fractured rocks accurate determination of thermodynamic and hydraulic properties is important. Heat capacity is one of the properties that are required to evaluate energy storage in the fractured rock. Rock-grain heat capacity, the subject of this study, is the heat capacity of the solid part of the rock. Yucca Mountain consists of alternating lithostratigraphic units of welded and non-welded ash-flow tuff, mainly rhyolitic in composition and displaying varying degrees of vitrification and alteration. A number of methods exist that can be used to evaluate heat capacity of the stratigraphic layers that consist of different compositions. In this study, the mineral summation method has been used to quantify the heat capacity of the stratigraphic layers based on Kopp's rule. The mineral summation method is an addition of the weighted heat capacity of each mineral found in a specific layer. For this study the weighting was done based on the mass percentage of each mineral in the layer. The method utilized a mineralogic map of the rocks at the Yucca Mountain repository site. The Calico Hills formation and adjacent bedded tuff layers display a bimodal mineral distribution of vitric and zeolitic zones with differing mineralogies. Based on this bimodal distribution in zeolite abundance, the boundary between the vitric and zeolitic zones was selected to be 15% zeolitic abundance. Thus, based on the zeolite abundance, subdivisions have been introduced to these layers into ''vitric'' and ''zeolitic'' zones. Heat capacity values have been calculated for these layers both as ''layer average'' and ''zone average''. The heat capacity determination method presented in this report did not account for spatial

  2. Prediction of Heat Removal Capacity of Horizontal Condensation Heat Exchanger submerged in Pool

    Energy Technology Data Exchange (ETDEWEB)

    Jeon, Seong-Su; Hong, Soon-Joon [FNC Tech., Yongin (Korea, Republic of); Cho, Hyoung-Kyu [Seoul National University, Seoul (Korea, Republic of); Park, Goon-Cherl [KEPCO International Nuclear Graduate School, Ulsan (Korea, Republic of)

    2014-10-15

    As representative passive safety systems, there are the passive containment cooling system (PCCS) of ESBWR, the emergency condenser system (ECS) of the SWR-1000, the passive auxiliary feed-water system (PAFS) of the APR+ and etc. During the nuclear power plant accidents, these passive safety systems can cool the nuclear system effectively via the heat transfer through the steam condensation, and then mitigate the accidents. For the optimum design and the safety analysis of the passive safety system, it is essential to predict the heat removal capacity of the heat exchanger well. The heat removal capacity of the horizontal condensation heat exchanger submerged in a pool is determined by a combination of a horizontal in-tube condensation heat transfer and a boiling heat transfer on the horizontal tube. Since most correlations proposed in the previous nuclear engineering field were developed for the vertical tube, there is a certain limit to apply these correlations to the horizontal tube. Therefore, this study developed the heat transfer model for the horizontal Ushaped condensation heat exchanger submerged in a pool to predict well the horizontal in-tube condensation heat transfer, the boiling heat transfer on the horizontal tube and the overall heat removal capacity of the heat exchanger using the best-estimate system analysis code, MARS.

  3. Building America Case Study: Impact of Improved Duct Insulation on Fixed-Capacity (SEER 13) and Variable-Capacity (SEER 22) Heat Pumps, Cocoa, Florida

    Energy Technology Data Exchange (ETDEWEB)

    2017-04-01

    A new generation of central, ducted variable-capacity heat pump systems has come on the market, promising very high cooling and heating efficiency. Instead of cycling on at full capacity and then cycling off when the thermostat is satisfied, they vary their cooling and heating output over a wide range (approximately 40 to 118% of nominal full capacity); thus, staying 'on' for 60% to 100% more hours per day compared to fixed-capacity systems. Current Phase 4 experiments in an instrumented lab home with simulated occupancy evaluate the impact of duct R-value enhancement on the overall operating efficiency of the variable-capacity system compared to the fixed-capacity system.

  4. A completely automated flow, heat-capacity, calorimeter for use at high temperatures and pressures

    Science.gov (United States)

    Rogers, P. S. Z.; Sandarusi, Jamal

    1990-11-01

    An automated, flow calorimeter has been constructed to measure the isobaric heat capacities of concentrated, aqueous electrolyte solutions using a differential calorimetry technique. The calorimeter is capable of operation to 700 K and 40 MPa with a measurement accuracy of 0.03% relative to the heat capacity of the pure reference fluid (water). A novel design encloses the calorimeter within a double set of separately controlled, copper, adiabatic shields that minimize calorimeter heat losses and precisely control the temperature of the inlet fluids. A multistage preheat train, used to efficiently heat the flowing fluid, includes a counter-current heat exchanger for the inlet and outlet fluid streams in tandem with two calorimeter preheaters. Complete system automation is accomplished with a distributed control scheme using multiple processors, allowing the major control tasks of calorimeter operation and control, data logging and display, and pump control to be performed simultaneously. A sophisticated pumping strategy for the two separate syringe pumps allows continuous fluid delivery. This automation system enables the calorimeter to operate unattended except for the reloading of sample fluids. In addition, automation has allowed the development and implementation of an improved heat loss calibration method that provides calorimeter calibration with absolute accuracy comparable to the overall measurement precision, even for very concentrated solutions.

  5. Frequency-dependent heat capacity

    DEFF Research Database (Denmark)

    Behrens, Claus Flensted

    The frequency–dependent heat capacity of super-cooled glycerol near the glass transition is measured using the 3w detection technique. An electrical conducting thin film with a temperature–dependent electrical resistance is deposited on a substrate. The thin film is used simultaneously as a heater...

  6. Specific Heat Capacity of Alloy 690 for Simulating Neutron Irradiation

    International Nuclear Information System (INIS)

    Park, Dae Gyu; Kim, Hee Moon; Song, Woong Sub; Baik, Seung Je; Joo, Young Sun; Ahn, Sang Bok; Park, Jin Seok; Lee, Won Jae; Ryu, Woo Seok

    2011-01-01

    The KAERI(Korea Atomic Energy Research Institute) is developing new type of nuclear reactor, so called 'SMART'(System Integrated Modular Advanced Reactor) which has many features of small power and system integrated modular type. Alloy 690 was selected as the candidate material for the heat exchanger tube of the steam generator of SMART. The SMART R and D is now facing the stage of engineering verification and approval of standard design to apply to DEMO reactors. Therefore, the material performance under the relevant environment is required to be evaluated. The important material performance issues are mechanical properties i.e. (fracture toughness, tensile and hardness) and thermal properties i.e. (thermal diffusivity, specific heat capacity and thermal conductivity) for which the engineering database is necessary to design a steam generator. However, the neutron post irradiation characteristics of the alloy 690 are barely known. As a result, PIE(Post Irradiation Examination) of thermal properties are planed and performed successfully. But specific heat capacity measurement is not performed because of not having proper test system for irradiated materials. Therefore in order to verify the effect of neutron irradiation for alloy 690, simulation method is adopted. In general, high energy neutron bombardment in material bring about lattice defects i.e. void, pore and dislocation. Dominant factor to impact to heat capacity is mainly dislocation in material. Therefore, simulation of neutron irradiation is devised by material rolling method in order to make artificial dislocation in alloy 690 as same effect of neutron irradiation. After preparing test specimens, heat capacity measurements are performed and results are compared with rolled materials and un-rolled materials to verify the effect of neutron irradiation simulation. Main interest of simulation is that heat capacity value is changed by neutron irradiation

  7. Temperature fluctuation and heat capacity in relativistic heavy-ion collisions

    CERN Document Server

    Ma, Guo Liang; Chen Jin Gen; He Ze-Jun; Long Jia-Li; Lu Zhao-Hui; Ma Yu-Gang; Sá Ben-Hao; Shen Wen-Qing; Wang Kun; Wei Yi-Bin; Zhang Hu-Yong; Zhong Chen

    2004-01-01

    We used LUCIAE3.0 model to simulate the Pb+Pb and C+C in SPS energy. The heat capacity was then extracted from event-by-event temperature fluctuation. It is found that the heat capacity per hadron multiplicity decreases with the increasing of beam energy and impact parameter for a given reaction system. While the hadron mass increases, the heat capacity per hadron multiplicity rises. In addition, we found that, for a given hadron, the heat capacity per hadron multiplicity is almost the same regardless of the reaction system. Some discussions were also given.

  8. A high performance cocurrent-flow heat pipe for heat recovery applications

    Science.gov (United States)

    Saaski, E. W.; Hartl, J. C.

    1980-01-01

    By the introduction of a plate-and-tube separator assembly into a heat pipe vapor core, it has been demonstrated that axial transport capacity in reflux mode can be improved by up to a factor of 10. This improvement is largely the result of eliminating the countercurrent shear that commonly limits reflux heat pipe axial capacity. With benzene, axial heat fluxes up to 1800 W/sq cm were obtained in the temperature range 40 to 80 C, while heat flux densities up to 3000 W/sq cm were obtained with R-11 over the temperature range 40 to 80 C. These very high axial capacities compare favorably with liquid metal limits; the sonic limit for liquid sodium, for example, is 3000 W/sq cm at 657 C. Computational models developed for these cocurrent flow heat pipes agreed with experimental data within + or - 25%.

  9. Suppression of the sonic heat transfer limit in high-temperature heat pipes

    Science.gov (United States)

    Dobran, Flavio

    1989-08-01

    The design of high-performance heat pipes requires optimization of heat transfer surfaces and liquid and vapor flow channels to suppress the heat transfer operating limits. In the paper an analytical model of the vapor flow in high-temperature heat pipes is presented, showing that the axial heat transport capacity limited by the sonic heat transfer limit depends on the working fluid, vapor flow area, manner of liquid evaporation into the vapor core of the evaporator, and lengths of the evaporator and adiabatic regions. Limited comparisons of the model predictions with data of the sonic heat transfer limits are shown to be very reasonable, giving credibility to the proposed analytical approach to determine the effect of various parameters on the axial heat transport capacity. Large axial heat transfer rates can be achieved with large vapor flow cross-sectional areas, small lengths of evaporator and adiabatic regions or a vapor flow area increase in these regions, and liquid evaporation in the evaporator normal to the main flow.

  10. First-principles calculations of heat capacities of ultrafast laser-excited electrons in metals

    International Nuclear Information System (INIS)

    Bévillon, E.; Colombier, J.P.; Recoules, V.; Stoian, R.

    2015-01-01

    Ultrafast laser excitation can induce fast increases of the electronic subsystem temperature. The subsequent electronic evolutions in terms of band structure and energy distribution can determine the change of several thermodynamic properties, including one essential for energy deposition; the electronic heat capacity. Using density functional calculations performed at finite electronic temperatures, the electronic heat capacities dependent on electronic temperatures are obtained for a series of metals, including free electron like, transition and noble metals. The effect of exchange and correlation functionals and the presence of semicore electrons on electronic heat capacities are first evaluated and found to be negligible in most cases. Then, we tested the validity of the free electron approaches, varying the number of free electrons per atom. This shows that only simple metals can be correctly fitted with these approaches. For transition metals, the presence of localized d electrons produces a strong deviation toward high energies of the electronic heat capacities, implying that more energy is needed to thermally excite them, compared to free sp electrons. This is attributed to collective excitation effects strengthened by a change of the electronic screening at high temperature

  11. Vibrational dynamics and heat capacity of polyglycine I.

    Science.gov (United States)

    Porwal, Vikas; Misra, Radha Mohan; Tandon, Poonam; Gupta, Vishwambhar Dayal

    2004-02-01

    Earlier works on polyglycine I suffer from several infirmities, such as the dynamic methylene group being replaced by a mass unit and the use of poorly resolved inelastic neutron spectra, which have resulted in wrong assignments and imprecise profile of dispersion curves. In addition, the density-of-states and heat capacity variation as a function of temperature are being reported for the first time. The heat capacity is in good agreement with the measurements reported earlier by Roles and Wunderlich within a certain range (230-350 K). Deviations set in beyond this could be due to the presence of two crystalline states (I and II) in the sample used for the heat capacity measurements.

  12. Apparatus intended for measuring heat capacity and heat transfer down to mK range

    International Nuclear Information System (INIS)

    Hebral, B.; Frossati, G.; Godfrin, H.; Schumacher, G.; Thoulouze, D.

    1978-01-01

    A cryogenic apparatus to perform heat capacity and heat transfer measurements in the range 1.5 mK-50 mK is described. Measurements are performed in an adiabatic demagnetization cell attached to a dilution refrigerator. Heat capacity measurements were effected on CMN-helium systems; the CMN specific heat was deduced above 1.6 mK when using liquid 3 He or a mixture 1.1% 3 He - 98.9% 4 He. A specific heat anomaly was observed with 4 He below 10 mK. It does not seen possible to interprete it by simple thermal equilibrium considerations. The superfluid 3 He heat capacity was also deduced from the results obtained with liquid 3 He under pressure. In heat transfer measurements at the interface CMN-mixture 3 He- 4 He, the temperature dependence of the thermal boundary resistance is in rather good agreement with other powder results. The measured resistances are larger than those predicted by the classical phonon process [fr

  13. Prediction of nanofluids properties: the density and the heat capacity

    Science.gov (United States)

    Zhelezny, V. P.; Motovoy, I. V.; Ustyuzhanin, E. E.

    2017-11-01

    The results given in this report show that the additives of Al2O3 nanoparticles lead to increase the density and decrease the heat capacity of isopropanol. Based on the experimental data the excess molar volume and the excess molar heat capacity were calculated. The report suggests new method for predicting the molar volume and molar heat capacity of nanofluids. It is established that the values of the excess thermodynamic functions are determined by the properties and the volume of the structurally oriented layers of the base fluid molecules near the surface of nanoparticles. The heat capacity of the structurally oriented layers of the base fluid is less than the heat capacity of the base fluid for given parameters due to the greater regulation of its structure. It is shown that information on the geometric dimensions of the structured layers of the base fluid near nanoparticles can be obtained from data on the nanofluids density and at ambient temperature - by the dynamic light scattering method. For calculations of the nanofluids heat capacity over a wide range of temperatures a new correlation based on the extended scaling is proposed.

  14. Low temperature heat capacity of lutetium and lutetium hydrogen alloys

    International Nuclear Information System (INIS)

    Thome, D.K.

    1977-10-01

    The heat capacity of high purity electrotransport refined lutetium was measured between 1 and 20 0 K. Results for theta/sub D/ were in excellent agreement with theta values determined from elastic constant measurements. The heat capacity of a series of lutetium-hydrogen solid solution alloys was determined and results showed an increase in γ from 8.2 to about 11.3 mJ/g-atom-K 2 for hydrogen content increasing from zero to about one atomic percent. Above one percent hydrogen γ decreased with increasing hydrogen contents. The C/T data showed an increase with temperature decreasing below about 2.5 0 K for samples with 0.1 to 1.5 atomic percent hydrogen. This accounts for a large amount of scatter in theta/sub D/ versus hydrogen content in this range. The heat capacity of a bulk sample of lutetium dihydride was measured between 1 and 20 0 K and showed a large increase in theta/sub D/ and a large decrease in γ compared to pure lutetium

  15. Hybrid Heat Capacity - Moving Slab Laser Concept

    International Nuclear Information System (INIS)

    Stappaerts, E A

    2002-01-01

    A hybrid configuration of a heat capacity laser (HCL) and a moving slab laser (MSL) has been studied. Multiple volumes of solid-state laser material are sequentially diode-pumped and their energy extracted. When a volume reaches a maximum temperature after a ''sub-magazine depth'', it is moved out of the pumping region into a cooling region, and a new volume is introduced. The total magazine depth equals the submagazine depth times the number of volumes. The design parameters are chosen to provide high duty factor operation, resulting in effective use of the diode arrays. The concept significantly reduces diode array cost over conventional heat capacity lasers, and it is considered enabling for many potential applications. A conceptual design study of the hybrid configuration has been carried out. Three concepts were evaluated using CAD tools. The concepts are described and their relative merits discussed. Because of reduced disk size and diode cost, the hybrid concept may allow scaling to average powers on the order of 0.5 MW/module

  16. Anomalous Behavior of Electronic Heat Capacity of Strongly Correlated Iron Monosilicide

    Science.gov (United States)

    Povzner, A. A.; Volkov, A. G.; Nogovitsyna, T. A.

    2018-04-01

    The paper deals with the electronic heat capacity of iron monosilicide FeSi subjected to semiconductor-metal thermal transition during which the formation of its spintronic properties is observed. The proposed model which considers pd-hybridization of strongly correlated d-electrons with non-correlated p-electrons, demonstrates a connection of their contribution to heat capacity in the insulator phase with paramagnon effects and fluctuations of occupation numbers for p- and d-states. In a slitless state, the temperature curve of heat capacity is characterized by a maximum appeared due to normalization of the electron density of states using fluctuating exchange fields. At higher temperatures, a linear growth in heat capacity occurs due to paramagnon effects. The correlation between the model parameters and the first-principles calculation provides the electron contribution to heat capacity, which is obtained from the experimental results on phonon heat capacity. Anharmonicity of phonons is connected merely with the thermal expansion of the crystal lattice.

  17. Liquid heat capacity of the solvent system (piperazine + n-methyldiethanolamine + water)

    International Nuclear Information System (INIS)

    Chen, Y.-R.; Caparanga, Alvin R.; Soriano, Allan N.; Li, M.-H.

    2010-01-01

    A new set of values for the heat capacity of aqueous mixtures of piperazine (PZ) and n-methyldiethanolamine (MDEA) at different concentrations and temperatures are reported in this paper. The differential scanning calorimetry technique was used to measure the property over the range T = 303.2 K to T = 353.2 K for mixtures containing 0.60 to 0.90 mole fraction water with 15 different concentrations of the system (PZ + MDEA + H 2 O). Heat capacity for four concentrations of the binary system (PZ + MDEA) was also measured. A Redlich-Kister-type equation was adopted to estimate the excess molar heat capacity, which was used to predict the value of the molar heat capacity at a particular concentration and temperature, which would then be compared against the measured value. A total of 165 data points fit into the model resulted in a low overall average absolute deviation of 4.6% and 0.3% for the excess molar heat capacity and molar heat capacity, respectively. Thus, the results presented here are of acceptable accuracy for use in engineering process design.

  18. Heat loss mechanisms in a measurement of specific heat capacity of graphite

    International Nuclear Information System (INIS)

    Shipley, D.R.; Duane, S.

    1996-01-01

    Absorbed dose to graphite in electron beams with nominal energies in the range 3-20 MeV is determined by measuring the temperature rise in the core of a primary standard graphite calorimeter. This temperature rise is related to absorbed dose by a separate measurement of the specific heat capacity of the graphite core. There is, however, a small but significant amount of heat loss from the sample in the determination of specific heat capacity and corrections for these losses are required. This report discusses the sources of heat loss in the measurements and, where possible, provides estimates for the magnitude of these losses. For those mechanisms which are significant, a more realistic model of the measurement system is analysed and corrections for the losses are provided. (UK)

  19. Effect of high energy electron beam (10 MeV) on specific heat capacity of low-density polyethylene/hydroxyapatite nano-composite

    Energy Technology Data Exchange (ETDEWEB)

    Soltani, Z., E-mail: zhr_soltani@yahoo.com [Health Physics and Radiation Dosimetry Research Laboratory, Department of Energy Engineering and Physics, Amirkabir University of Technology, Tehran (Iran, Islamic Republic of); Ziaie, F. [Radiation Application Research School, Nuclear Science & Technology Research Institute, Tehran (Iran, Islamic Republic of); Ghaffari, M. [Polymer Group, Golestan University, Golestan (Iran, Islamic Republic of); Beigzadeh, A.M. [Radiation Application Research School, Nuclear Science & Technology Research Institute, Tehran (Iran, Islamic Republic of)

    2017-02-01

    In the present work, thermal properties of low density polyethylene (LDPE) and its nano composites are investigated. For this purpose LDPE reinforced with different weight percents of hydroxyapatite (HAP) powder which was synthesized via hydrolysis method are produced. The samples were irradiated with 10 MeV electron beam at doses of 75 to 250 kGy. Specific heat capacity measurement have been carried out at different temperatures, i.e. 25, 50, 75 and 100 °C using modulated temperature differential scanning calorimetry (MTDSC) apparatus and the effect of three parameters include of temperature, irradiation dose and the amount of HAP nano particles as additives on the specific heat capacity of PE/HAP have been investigated precisely. The MTDSC results indicate that the specific heat capacity have decreased by addition of nano sized HAP as reinforcement for LDPE. On the other hand, the effect of radiation dose is reduction in the specific heat capacity in all materials including LDPE and its nano composites. The HAP nano particles along with cross-link junctions due to radiation restrain the movement of the polymer chains in the vicinity of each particle and improve the immobility of polymer chains and consequently lead to reduction in specific heat capacity. Also, the obtained results confirm that the radiation effect on the specific heat capacity is more efficient than the reinforcing effect of nano-sized hydroxyapatite.

  20. Preliminary Analysis on Heat Removal Capacity of Passive Air-Water Combined Cooling Heat Exchanger Using MARS

    International Nuclear Information System (INIS)

    Kim, Seung-Sin; Jeon, Seong-Su; Hong, Soon-Joon; Bae, Sung-Won; Kwon, Tae-Soon

    2015-01-01

    Current design requirement for working time of PAFS heat exchanger is about 8 hours. Thus, it is not satisfied with the required cooling capability for the long term SBO(Station Black-Out) situation that is required to over 72 hours cooling. Therefore PAFS is needed to change of design for 72 hours cooling. In order to acquirement of long terms cooling using PAFS, heat exchanger tube has to be submerged in water tank for long time. However, water in the tank is evaporated by transferred heat from heat exchanger tubes, so water level is gradually lowered as time goes on. The heat removal capacity of air cooling heat exchanger is core parameter that is used for decision of applicability on passive air-water combined cooling system using PAFS in long term cooling. In this study, the development of MARS input model and plant accident analysis are performed for the prediction of the heat removal capacity of air cooling heat exchanger. From analysis result, it is known that inflow air velocity is the decisive factor of the heat removal capacity and predicted air velocity is lower than required air velocity. But present heat transfer model and predicted air velocity have uncertainty. So, if changed design of PAFS that has over 4.6 kW heat removal capacity in each tube, this type heat exchanger can be applied to long term cooling of the nuclear power plant

  1. Influence of Fuel Meat Porosity on Heat Capacities of Fuel Element Plate U3Si2-Al

    International Nuclear Information System (INIS)

    Ginting, Aslina Br.; Supardjo; Sutri Indaryati

    2007-01-01

    Analyze of heat capacities of Al powder, AIMg 2 cladding, U 3 Si 2 powder and PEB U 3 Si 2 -Al with the meat porosity of 4.9; 5.53 ; 6.25 ; 6.95 %; 7.90; 8.66% have been done. Analysis was conducted by using Differential Scanning Calorimeter (DSC) at temperature 30℃ to 450℃ with heating rate 1℃ /minute in Argon gas media. The purpose of analyze is to know the influence of increasing of fuel meat porosity on heat capacities because increasing of percentage of meat porosity will cause degradation the of heat capacities of PEB U 3 Si 2 -Al. Result of analysis showed that the heat capacities of Al powder, AIMg 2 cladding increase by temperature, while heat capacities of U 3 Si 2 powder was stable with increasing of temperature up to 450℃. Analysis of heat capacities toward PEB U 3 Si 2 -Al indicate that increasing of fuel meat porosity of caused degradation of the heat capacities of PEB U 3 Si 2 -Al. Data obtained were expected to serve the purpose of input to fabricator of research reactor fuel in for design of fuel element type silicide with high loading. (author)

  2. A high-temperature high-pressure calorimeter for determining heats of solution up to 623 K.

    Science.gov (United States)

    Djamali, Essmaiil; Turner, Peter J; Murray, Richard C; Cobble, James W

    2010-07-01

    A high-temperature high-pressure isoperibol calorimeter for determining the heats of solution and reaction of very dilute substances in water (10(-4) m) at temperatures up to 623 K is described. The energies of vaporization of water at steam saturation pressure were measured as a function of temperature and the results agree with the corresponding values from steam tables to better than 0.08+/-0.18%. The novelties of the present instrument relative to flow type heat capacity calorimeters are that measurements can be made at orders of magnitude lower concentrations and that measurement of heat of reaction involving solids or gases or in the presence of high concentrations of supporting electrolytes, acids, and bases is possible. Furthermore, the advantage of using enthalpy data over heat capacity data for calculations of the standard state Gibbs free energies of electrolytes is that the experimental heat data of this research need only be integrated once to derive higher temperature free energy data from lower temperatures. The derived heat capacities can be used mathematically to obtain free energies by double integration. However, the resulting errors are much smaller than if experimental aqueous heat capacities were used for the integrations.

  3. Effect of surface hydroxyl groups on heat capacity of mesoporous silica

    Science.gov (United States)

    Marszewski, Michal; Butts, Danielle; Lan, Esther; Yan, Yan; King, Sophia C.; McNeil, Patricia E.; Galy, Tiphaine; Dunn, Bruce; Tolbert, Sarah H.; Hu, Yongjie; Pilon, Laurent

    2018-05-01

    This paper quantifies the effect of surface hydroxyl groups on the effective specific and volumetric heat capacities of mesoporous silica. To achieve a wide range of structural diversity, mesoporous silica samples were synthesized by various methods, including (i) polymer-templated nanoparticle-based powders, (ii) polymer-templated sol-gel powders, and (iii) ambigel silica samples dried by solvent exchange at room temperature. Their effective specific heat capacity, specific surface area, and porosity were measured using differential scanning calorimetry and low-temperature nitrogen adsorption-desorption measurements. The experimentally measured specific heat capacity was larger than the conventional weight-fraction-weighted specific heat capacity of the air and silica constituents. The difference was attributed to the presence of OH groups in the large internal surface area. A thermodynamic model was developed based on surface energy considerations to account for the effect of surface OH groups on the specific and volumetric heat capacity. The model predictions fell within the experimental uncertainty.

  4. Landau-Placzek ratio for heat density dynamics and its application to heat capacity of liquids.

    Science.gov (United States)

    Bryk, Taras; Ruocco, Giancarlo; Scopigno, Tullio

    2013-01-21

    Exact relation for contributions to heat capacity of liquids is obtained from hydrodynamic theory. It is shown from analysis of the long-wavelength limit of heat density autocorrelation functions that the heat capacity of simple liquids is represented as a sum of two contributions due to "phonon-like" collective excitations and heat relaxation. The ratio of both contributions being the analogy of Landau-Placzek ratio for heat processes depends on the specific heats ratio. The theory of heat density autocorrelation functions in liquids is verified by computer simulations. Molecular dynamics simulations for six liquids having the ratio of specific heats γ in the range 1.1-2.3, were used for evaluation of the heat density autocorrelation functions and predicted Landau-Placzek ratio for heat processes. The dependence of contributions from collective excitations and heat relaxation process to specific heat on γ is shown to be in excellent agreement with the theory.

  5. Reductions in labour capacity from heat stress under climate warming

    Science.gov (United States)

    Dunne, John P.; Stouffer, Ronald J.; John, Jasmin G.

    2013-06-01

    A fundamental aspect of greenhouse-gas-induced warming is a global-scale increase in absolute humidity. Under continued warming, this response has been shown to pose increasingly severe limitations on human activity in tropical and mid-latitudes during peak months of heat stress. One heat-stress metric with broad occupational health applications is wet-bulb globe temperature. We combine wet-bulb globe temperatures from global climate historical reanalysis and Earth System Model (ESM2M) projections with industrial and military guidelines for an acclimated individual's occupational capacity to safely perform sustained labour under environmental heat stress (labour capacity)--here defined as a global population-weighted metric temporally fixed at the 2010 distribution. We estimate that environmental heat stress has reduced labour capacity to 90% in peak months over the past few decades. ESM2M projects labour capacity reduction to 80% in peak months by 2050. Under the highest scenario considered (Representative Concentration Pathway 8.5), ESM2M projects labour capacity reduction to less than 40% by 2200 in peak months, with most tropical and mid-latitudes experiencing extreme climatological heat stress. Uncertainties and caveats associated with these projections include climate sensitivity, climate warming patterns, CO2 emissions, future population distributions, and technological and societal change.

  6. The lumped heat capacity method applied to target heating

    OpenAIRE

    Rickards, J.

    2013-01-01

    The temperature of metal samples was measured while they were bombarded by the beam from the a particle accelerator. The evolution of the temperature with time can be explained using the lumped heat capacity method of heat transfer. A strong dependence on the type of mounting was found. Se midió la temperatura de muestras metálicas al ser bombardeadas por el haz de iones del Acelerador Pelletron del Instituto de Física. La evolución de la temperatura con el tiempo se puede explicar usando ...

  7. ISOCHORIC HEAT CAPACITY OF 1% AQUEOUS SOLUTION OF MAGNESIUM CHLORIDE

    Directory of Open Access Journals (Sweden)

    V. I. Dvoryanchikov

    2016-01-01

    Full Text Available Aim. The aim is to conduct an experimental study of isochoric heat capacity of 1% aqueous solution of magnesium chloride along the phase boundary curve.Method. In order to determine the isochoric heat capacity at the phase boundary curve we used the adiabatic calorimeter of KH. I. Amirkhanov.Results. Results of the study of the isochoric heat capacity depending on the temperature are given in tables and figures; the findings are compared with those of other researchers. When evaluating a complex system, we ought not to evaluate its effectiveness on the basis of only one criterion, even a very important, in this case must take into account the requirements of the technical, economic, environmental and of other natures.Conclusions. When solving optimization problems of efficiency in geothermal energy it is necessary to take into account the fact of the temperature dependence of the heat and density. The temperature dependence of the density and heat capacity in the calculations significantly affect the value of the efficiency criterion to be taken into account, otherwise the calculation error can be up to 20%. The data obtained from the isochoric heat capacity of aqueous solutions of magnesium chloride is compared with the data for water and aqueous solutions of NaCl and NaOH, obtained previously, which may be represented as a model of geothermal and sea water.

  8. Evaluation of Heat Capacity and Resistance to Cyclic Oxidation of Nickel Superalloys

    Directory of Open Access Journals (Sweden)

    Przeliorz R.

    2014-08-01

    Full Text Available Paper presents the results of evaluation of heat resistance and specific heat capacity of MAR-M-200, MAR-M-247 and Rene 80 nickel superalloys. Heat resistance was evaluated using cyclic method. Every cycle included heating in 1100°C for 23 hours and cooling for 1 hour in air. Microstructure of the scale was observed using electron microscope. Specific heat capacity was measured using DSC calorimeter. It was found that under conditions of cyclically changing temperature alloy MAR-M-247 exhibits highest heat resistance. Formed oxide scale is heterophasic mixture of alloying elements, under which an internal oxidation zone was present. MAR-M-200 alloy has higher specific heat capacity compared to MAR-M-247. For tested alloys in the temperature range from 550°C to 800°C precipitation processes (γ′, γ″ are probably occurring, resulting in a sudden increase in the observed heat capacity.

  9. Standard partial molar heat capacities and enthalpies of formation of aqueous aluminate under hydrothermal conditions from integral heat of solution measurements

    International Nuclear Information System (INIS)

    Coulier, Yohann; Tremaine, Peter R.

    2014-01-01

    Highlights: • Heats of solution of NaAlO 2 (s) were measured at five temperatures up to 250 °C. • Standard molar enthalpies of solution were determined from the measured heats of solution. • Standard molar enthalpies of solution were correlated with the density model. • The density model allows us to determine the standard molar heat capacities of reaction. - Abstract: Heats of solution of sodium aluminum oxide, NaAlO 2 (s), were measured in aqueous sodium hydroxide solutions using a Tian–Calvet heat-flow calorimeter (Setaram, Model C80) with high pressure “batch cells” made of hastelloy C-276, at five temperatures from (373.15 to 523.15) K, steam saturation pressure, and concentrations from (0.02 to 0.09) mol · kg −1 . Standard molar enthalpies of solution, Δ soln H ∘ , and relative standard molar enthalpies, [H ∘ (T) − H ∘ (298.15 K)], of NaAl(OH) 4 (aq) were determined from the measured heats of solution. The results were fitted with the “density” model. The temperature dependence of Δ soln H ∘ from the model yielded the standard molar heat capacities of reaction, Δ soln C p ∘ , from which standard partial molar heat capacities for aqueous aluminate, C p ∘ [A1(OH) 4 − ,aq], were calculated. Standard partial molar enthalpies of formation, Δ f H ∘ , and entropies, S ∘ , of A1(OH) 4 − (aq) were also determined. The values for C p ∘ [A1(OH) 4 − ,aq] agree with literature data determined up to T = 413 K from enthalpy of solution and heat capacity measurements to within the combined experimental uncertainties. They are consistent with differential heat capacity measurements up to T = 573 K from Schrödle et al. (2010) [29] using the same calorimeter, but this method has the advantage that measurements could be made at much lower concentrations in the presence of an excess concentration of ligand. To our knowledge, these are the first standard partial molar heat capacities measured under hydrothermal conditions by the

  10. Heat capacity measurements and XPS studies on uranium-lanthanum mixed oxides

    International Nuclear Information System (INIS)

    Venkata Krishnan, R.; Mittal, V.K.; Babu, R.; Senapati, Abhiram; Bera, Santanu; Nagarajan, K.

    2011-01-01

    Research highlights: → Heat capacity measurements were carried out on (U 1-y La y )O 2±x (y = 0.2, 0.4, 0.6, and 0.8) using differential scanning calorimeter (DSC) in the temperature range 298-800 K. → Enthalpy increment measurements were carried out on the above solid solution using high temperature drop calorimetry in the temperature range 800-1800 K. → Chemical states of U and La in the solid solutions of mixed oxides were determined using X-ray photoelectron spectroscopy (XPS). → The anomalous increase in the heat capacity is attributed to certain thermal excitation process namely Frenkel pair defect of oxygen. → From the XPS investigation, it is observed that the O/M ratio at the surface is higher than that to the bulk. → In uranium rich mixed oxide samples, the surface O/M is greater than 2 whereas that in La rich mixed oxides, it is less than 2, though the bulk O/M in all the samples are less than 2. - Abstract: Heat capacity measurements were carried out on (U 1-y La y )O 2±x (y = 0.2, 0.4, 0.6, and 0.8) using differential scanning calorimeter (DSC) in the temperature range 298-800 K. Enthalpy increment measurements were carried out on the above solid solutions using high temperature drop calorimetry in the temperature range 800-1800 K. Chemical states of U and La in the solid solutions of mixed oxides were determined using X-ray photoelectron spectroscopy (XPS). Oxygen to metal ratios of (U 1-y La y )O 2±x were estimated from the ratios of different chemical states of U present in the sample. Anomalous increase in the heat capacity is observed for (U 1-y La y )O 2±x (y = 0.4, 0.6 and 0.8) with onset temperatures in the range of 1000-1200 K. The anomalous increase in the heat capacity is attributed to certain thermal excitation process, namely, Frenkel pair defect of oxygen. The heat capacity value of (U 1-y La y )O 2±x (y = 0.2, 0.4, 0.6, and 0.8) at 298 K are 65.3, 64.1, 57.7, 51.9 J K -1 mol -1 , respectively. From the XPS investigations

  11. Solvation thermodynamics and heat capacity of polar and charged solutes in water

    Science.gov (United States)

    Sedlmeier, Felix; Netz, Roland R.

    2013-03-01

    The solvation thermodynamics and in particular the solvation heat capacity of polar and charged solutes in water is studied using atomistic molecular dynamics simulations. As ionic solutes we consider a F- and a Na+ ion, as an example for a polar molecule with vanishing net charge we take a SPC/E water molecule. The partial charges of all three solutes are varied in a wide range by a scaling factor. Using a recently introduced method for the accurate determination of the solvation free energy of polar solutes, we determine the free energy, entropy, enthalpy, and heat capacity of the three different solutes as a function of temperature and partial solute charge. We find that the sum of the solvation heat capacities of the Na+ and F- ions is negative, in agreement with experimental observations, but our results uncover a pronounced difference in the heat capacity between positively and negatively charged groups. While the solvation heat capacity ΔCp stays positive and even increases slightly upon charging the Na+ ion, it decreases upon charging the F- ion and becomes negative beyond an ion charge of q = -0.3e. On the other hand, the heat capacity of the overall charge-neutral polar solute derived from a SPC/E water molecule is positive for all charge scaling factors considered by us. This means that the heat capacity of a wide class of polar solutes with vanishing net charge is positive. The common ascription of negative heat capacities to polar chemical groups might arise from the neglect of non-additive interaction effects between polar and apolar groups. The reason behind this non-additivity is suggested to be related to the second solvation shell that significantly affects the solvation thermodynamics and due to its large spatial extent induces quite long-ranged interactions between solvated molecular parts and groups.

  12. Experimental study on heat pipe heat removal capacity for passive cooling of spent fuel pool

    International Nuclear Information System (INIS)

    Xiong, Zhenqin; Wang, Minglu; Gu, Hanyang; Ye, Cheng

    2015-01-01

    Highlights: • A passively cooling SFP heat pipe with an 8.2 m high evaporator was tested. • Heat removed by the heat pipe is in the range of 3.1–16.8 kW. • The heat transfer coefficient of the evaporator is 214–414 W/m 2 /K. • The heat pipe performance is sensitive to the hot water temperature. - Abstract: A loop-type heat pipe system uses natural flow with no electrically driven components. Therefore, such a system was proposed to passively cool spent fuel pools during accidents to improve nuclear power station safety especially for station blackouts such as those in Fukushima. The heat pipe used for a spent fuel pool is large due to the spent fuel pool size. An experimental heat pipe test loop was developed to estimate its heat removal capacity from the spent fuel pool during an accident. The 7.6 m high evaporator is heated by hot water flowing vertically down in an assistant tube with a 207-mm inner diameter. R134a was used as the potential heat pipe working fluid. The liquid R134a level was 3.6 m. The tests were performed for water velocities from 0.7 to 2.1 × 10 −2 m/s with water temperatures from 50 to 90 °C and air velocities from 0.5 m/s to 2.5 m/s. The results indicate significant heat is removed by the heat pipe under conditions that may occur in the spent fuel pool

  13. Determination of the Temperature Dependence of Heat Capacity for Some Molecular Crystals of Nitro Compounds

    Science.gov (United States)

    Kovalev, Yu. M.; Kuropatenko, V. F.

    2018-05-01

    An analysis of the existing approximations used for describing the dependence of heat capacity at a constant volume on the temperature of a molecular crystal has been carried out. It is shown that the considered Debye and Einstein approximations do not enable one to adequately describe the dependence of heat capacity at a constant volume on the temperature of the molecular crystals of nitro compounds. This inference requires the development of special approximations that would describe both low-frequency and high-frequency parts of the vibrational spectra of molecular crystals. This work presents a universal dependence allowing one to describe the dependence of heat capacity at a constant volume on temperature for a number of molecular crystals of nitro compounds.

  14. Heat Capacity of Room-Temperature Ionic Liquids: A Critical Review

    Science.gov (United States)

    Paulechka, Yauheni U.

    2010-09-01

    Experimental data on heat capacity of room-temperature ionic liquids in the liquid state were compiled and critically evaluated. The compilation contains data for 102 aprotic ionic liquids from 63 literature references and covers the period of time from 1998 through the end of February 2010. Parameters of correlating equations for temperature dependence of the heat capacities were developed.

  15. Negative heat capacities in central Xe+Sn reactions

    International Nuclear Information System (INIS)

    Le Neindre, N.; Bougault, R.; Gulminelli, F.

    2000-02-01

    In this study the fluctuation method is applied to the 32-50 A.MeV Xe + Sn central collisions detected with the INDRA multidetector. This method based on kinetic energy fluctuations allows the authors to provide information on the liquid gas phase transition in nuclear multifragmentation. In the case of Xe + Sn central reactions a divergence in the total heat capacity is observed. This divergence corresponds to large fluctuations on the detected fragment partitions. A negative heat capacity branch is measured and so tends to confirm the observation of a first order phase transition in heavy-ion collisions. (A.C.)

  16. Heat capacities of several Co{sub 2}YZ Heusler compounds

    Energy Technology Data Exchange (ETDEWEB)

    Yin, Ming, E-mail: myin1@hawk.iit.edu; Nash, Philip; Chen, Song

    2013-12-20

    Highlights: • Heat contents from 600 K to 1500 K of selected Co{sub 2}YZ were measured by drop calorimeters. • Heat capacities were obtained by taking derivatives of heats contents which were fitted with second order polynomial with respect to temperature. • Melting points determined by DSC were consistent with literature data. • Heats of fusion determined by DSC were comparable with those obtained by extrapolation of heat contents. - Abstract: Heat contents of several Co{sub 2}-based Heusler compounds Co{sub 2}YZ (Y = Fe, Mn, Ti; Z = Al, Ga, Si, Ge, Sn) were measured from 500 K to 1500 K using a Setaram MTHC 96 drop calorimeter. Second order polynomials were adopted to fit the data and heat capacities were obtained by taking the derivatives with respect to temperature. Melting points were determined by differential scanning calorimetry (DSC) and measured heats of fusion were compared with those obtained from extrapolation of heat contents.

  17. Optimum performance analysis of an irreversible Diesel heat engine affected by variable heat capacities of working fluid

    International Nuclear Information System (INIS)

    Zhao, Yingru; Chen, Jincan

    2007-01-01

    An irreversible cycle model of the Diesel heat engine is established in which the temperature dependent heat capacities of the working fluid, the irreversibilities resulting from non-isentropic compression and expansion processes and heat leak losses through the cylinder wall are taken into account. The adiabatic equation of ideal gases with temperature dependent heat capacity is strictly deduced without using the additional approximation condition in the relevant literature and is used to analyze the performance of the Diesel heat engine. Expressions for the work output and efficiency of the cycle are derived by introducing the pressure ratio and the compression and expansion efficiencies. The performance characteristic curves of the Diesel heat engine are presented for a set of given parameters. The optimum criteria of some important parameters such as the work output, efficiency, pressure ratio and temperatures of the working fluid are obtained. Moreover, the influence of the compression and expansion efficiencies, variable heat capacities, heat leak and other parameters on the performance of the cycle is discussed in detail. The results obtained may provide a theoretical basis for both optimal design and operation of real Diesel heat engines

  18. An experimental study of the enhanced heating capacity of an electric heat pump (EHP) using the heat recovered from a gas engine generator

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Cheol Min; Chang, Se Dong [HAC R and D Laboratory, LG Electronics, 327-23 Gasan-Dong, Geumcheon-gu, Seoul 153-802 (Korea); Lee, Jaekeun; Hwang, Yujin [School of Mechanical Engineering, Pusan National University, San 30, Changjeon-Dong, Keumjeong-Ku, Busan 609-735 (Korea)

    2009-11-15

    This paper is concerned with the effect of recovered heat on the heating capacity of an Electric Heat Pump (EHP), which is supplied with electric power and recovered heat from a gas engine generator system. Two methods of supplying recovery heat are examined: (i) to the refrigerant with the discharge line heat exchanger (HEX), and (ii) to the refrigerant of the evaporator with the sub-evaporator. Heating capacity, input power and coefficient of performance (COP) were investigated and compared for each heat recovery method. Conclusively, we found that the second method was most reasonable to recover wasted heat and increased system COP by 215%. (author)

  19. Cyclic high temperature heat storage using borehole heat exchangers

    Science.gov (United States)

    Boockmeyer, Anke; Delfs, Jens-Olaf; Bauer, Sebastian

    2016-04-01

    The transition of the German energy supply towards mainly renewable energy sources like wind or solar power, termed "Energiewende", makes energy storage a requirement in order to compensate their fluctuating production and to ensure a reliable energy and power supply. One option is to store heat in the subsurface using borehole heat exchangers (BHEs). Efficiency of thermal storage is increasing with increasing temperatures, as heat at high temperatures is more easily injected and extracted than at temperatures at ambient levels. This work aims at quantifying achievable storage capacities, storage cycle times, injection and extraction rates as well as thermal and hydraulic effects induced in the subsurface for a BHE storage site in the shallow subsurface. To achieve these aims, simulation of these highly dynamic storage sites is performed. A detailed, high-resolution numerical simulation model was developed, that accounts for all BHE components in geometrical detail and incorporates the governing processes. This model was verified using high quality experimental data and is shown to achieve accurate simulation results with excellent fit to the available experimental data, but also leads to large computational times due to the large numerical meshes required for discretizing the highly transient effects. An approximate numerical model for each type of BHE (single U, double U and coaxial) that reduces the number of elements and the simulation time significantly was therefore developed for use in larger scale simulations. The approximate numerical model still includes all BHE components and represents the temporal and spatial temperature distribution with a deviation of less than 2% from the fully discretized model. Simulation times are reduced by a factor of ~10 for single U-tube BHEs, ~20 for double U-tube BHEs and ~150 for coaxial BHEs. This model is then used to investigate achievable storage capacity, injection and extraction rates as well as induced effects for

  20. Determination of the heat capacities of Lithium/BCX (bromide chloride in thionyl chloride) batteries

    Science.gov (United States)

    Kubow, Stephen A.; Takeuchi, Kenneth J.; Takeuchi, Esther S.

    1989-12-01

    Heat capacities of twelve different Lithium/BCX (BrCl in thionyl chloride) batteries in sizes AA, C, D, and DD were determined. Procedures and measurement results are reported. The procedure allowed simple, reproducible, and precise determinations of heat capacities of industrially important Lithium/BCX cells, without interfering with performance of the cells. Use of aluminum standards allowed the accuracy of the measurements to be maintained. The measured heat capacities were within 5 percent of calculated heat capacity values.

  1. Peak capacity, peak-capacity production rate, and boiling point resolution for temperature-programmed GC with very high programming rates

    Science.gov (United States)

    Grall; Leonard; Sacks

    2000-02-01

    Recent advances in column heating technology have made possible very fast linear temperature programming for high-speed gas chromatography. A fused-silica capillary column is contained in a tubular metal jacket, which is resistively heated by a precision power supply. With very rapid column heating, the rate of peak-capacity production is significantly enhanced, but the total peak capacity and the boiling-point resolution (minimum boiling-point difference required for the separation of two nonpolar compounds on a nonpolar column) are reduced relative to more conventional heating rates used with convection-oven instruments. As temperature-programming rates increase, elution temperatures also increase with the result that retention may become insignificant prior to elution. This results in inefficient utilization of the down-stream end of the column and causes a loss in the rate of peak-capacity production. The rate of peak-capacity production is increased by the use of shorter columns and higher carrier gas velocities. With high programming rates (100-600 degrees C/min), column lengths of 6-12 m and average linear carrier gas velocities in the 100-150 cm/s range are satisfactory. In this study, the rate of peak-capacity production, the total peak capacity, and the boiling point resolution are determined for C10-C28 n-alkanes using 6-18 m long columns, 50-200 cm/s average carrier gas velocities, and 60-600 degrees C/min programming rates. It was found that with a 6-meter-long, 0.25-mm i.d. column programmed at a rate of 600 degrees C/min, a maximum peak-capacity production rate of 6.1 peaks/s was obtained. A total peak capacity of about 75 peaks was produced in a 37-s long separation spanning a boiling-point range from n-C10 (174 degrees C) to n-C28 (432 degrees C).

  2. High-Capacity Spacesuit Evaporator Absorber Radiator (SEAR)

    Science.gov (United States)

    Izenson, Michael G.; Chen, Weibo; Phillips, Scott; Chepko, Ariane; Bue, Grant; Quinn, Gregory

    2015-01-01

    Future human space exploration missions will require advanced life support technology that can operate across a wide range of applications and environments. Thermal control systems for space suits and spacecraft will need to meet critical requirements for water conservation and multifunctional operation. This paper describes a Space Evaporator Absorber Radiator (SEAR) that has been designed to meet performance requirements for future life support systems. A SEAR system comprises a lithium chloride absorber radiator (LCAR) for heat rejection coupled with a space water membrane evaporator (SWME) for heat acquisition. SEAR systems provide heat pumping to minimize radiator size, thermal storage to accommodate variable environmental conditions, and water absorption to minimize use of expendables. We have built and tested a flight-like, high-capacity LCAR, demonstrated its performance in thermal vacuum tests, and explored the feasibility of an ISS demonstration test of a SEAR system. The new LCAR design provides the same cooling capability as prior LCAR prototypes while enabling over 30% more heat absorbing capacity. Studies show that it should be feasible to demonstrate SEAR operation in flight by coupling with an existing EMU on the space station.

  3. Heat capacity of SrThO3

    International Nuclear Information System (INIS)

    Kumar, Ginish; Raut, Sheetal; Agarwal, Renu; Mukerjee, S.K.

    2016-01-01

    Thorium is more abundant in nature than uranium, therefore, it is expected to play an important role in the third stage of Indian nuclear power generation program. An advanced heavy water reactor, with thorium oxide based fuels, is being developed in India, with an aim of utilizing thorium for power generation. Alkaline earth elements, Ba and Sr, with significant fission yield (6.3%), react with fuel and precipitate out as a separate phase. Thermodynamic properties of fuel-fission product compounds are needed to understand behaviour of fuel at high burn-ups, therefore, it was decided to investigate heat capacity of SrThO 3

  4. Retrofitting of heat exchanger networks involving streams with variable heat capacity: Application of single and multi-objective optimization

    International Nuclear Information System (INIS)

    Sreepathi, Bhargava Krishna; Rangaiah, G.P.

    2015-01-01

    Heat exchanger network (HEN) retrofitting improves the energy efficiency of the current process by reducing external utilities. In this work, HEN retrofitting involving streams having variable heat capacity is studied. For this, enthalpy values of a stream are fitted to a continuous cubic polynomial instead of a stepwise approach employed in the previous studies [1,2]. The former methodology is closer to reality as enthalpy or heat capacity changes gradually instead of step changes. Using the polynomial fitting formulation, single objective optimization (SOO) and multi-objective optimization (MOO) of a HEN retrofit problem are investigated. The results obtained show an improvement in the utility savings, and MOO provides many Pareto-optimal solutions to choose from. Also, Pareto-optimal solutions involving area addition in existing heat exchangers only (but no new exchangers and no structural modifications) are found and provided for comparison with those involving new exchangers and structural modifications as well. - Highlights: • HEN retrofitting involving streams with variable heat capacities is studied. • A continuous approach to handle variable heat capacity is proposed and tested. • Better and practical solutions are obtained for HEN retrofitting in process plants. • Pareto-optimal solutions provide many alternate choices for HEN retrofitting

  5. Low-temperature heat capacity and thermodynamic functions of vitamin B12

    International Nuclear Information System (INIS)

    Knyazev, A.V.; Smirnova, N.N.; Plesovskikh, A.S.; Shushunov, A.N.; Knyazeva, S.S.

    2014-01-01

    Graphical abstract: - Highlights: • Temperature dependence of heat capacity of vitamin B 12 has been measured by precision adiabatic vacuum calorimetry. • The thermodynamic functions of the vitamin B 12 have been determined for the range from T → 0 to 343 K. • The character of heterodynamics of structure was detected. • The thermal stability of cyanocobalamin was studied by differential scanning calorimetry. - Abstract: In the present work temperature dependence of heat capacity of vitamin B 12 (cyanocobalamin) has been measured for the first time in the range from 6 to 343 K by precision adiabatic vacuum calorimetry. Based on the experimental data, the thermodynamic functions of the vitamin B 12 , namely, the heat capacity, enthalpy H°(T) − H°(0), entropy S°(T) − S°(0) and Gibbs function G°(T) − H°(0) have been determined for the range from T → 0 to 343 K. The value of the fractal dimension D in the function of multifractal generalization of Debye's theory of the heat capacity of solids was estimated and the character of heterodynamics of structure was detected. The thermal stability of cyanocobalamin was also studied by differential scanning calorimetry

  6. Working Fluids for Increasing Capacities of Heat Pipes

    Science.gov (United States)

    Chao, David F.; Zhang, Nengli

    2004-01-01

    A theoretical and experimental investigation has shown that the capacities of heat pipes can be increased through suitable reformulation of their working fluids. The surface tensions of all of the working fluids heretofore used in heat pipes decrease with temperature. As explained in more detail below, the limits on the performance of a heat pipe are associated with the decrease in the surface tension of the working fluid with temperature, and so one can enhance performance by reformulating the working fluid so that its surface tension increases with temperature. This improvement is applicable to almost any kind of heat pipe in almost any environment. The heat-transfer capacity of a heat pipe in its normal operating-temperature range is subject to a capillary limit and a boiling limit. Both of these limits are associated with the temperature dependence of surface tension of the working fluid. In the case of a traditional working fluid, the decrease in surface tension with temperature causes a body of the liquid phase of the working fluid to move toward a region of lower temperature, thus preventing the desired spreading of the liquid in the heated portion of the heat pipe. As a result, the available capillary-pressure pumping head decreases as the temperature of the evaporator end of the heat pipe increases, and operation becomes unstable. Water has widely been used as a working fluid in heat pipes. Because the surface tension of water decreases with increasing temperature, the heat loads and other aspects of performance of heat pipes that contain water are limited. Dilute aqueous solutions of long-chain alcohols have shown promise as substitutes for water that can offer improved performance, because these solutions exhibit unusual surface-tension characteristics: Experiments have shown that in the cases of an aqueous solution of an alcohol, the molecules of which contain chains of more than four carbon atoms, the surface tension increases with temperature when the

  7. Measurement and Model Validation of Nanofluid Specific Heat Capacity with Differential Scanning Calorimetry

    Directory of Open Access Journals (Sweden)

    Harry O'Hanley

    2012-01-01

    Full Text Available Nanofluids are being considered for heat transfer applications; therefore it is important to know their thermophysical properties accurately. In this paper we focused on nanofluid specific heat capacity. Currently, there exist two models to predict a nanofluid specific heat capacity as a function of nanoparticle concentration and material. Model I is a straight volume-weighted average; Model II is based on the assumption of thermal equilibrium between the particles and the surrounding fluid. These two models give significantly different predictions for a given system. Using differential scanning calorimetry (DSC, a robust experimental methodology for measuring the heat capacity of fluids, the specific heat capacities of water-based silica, alumina, and copper oxide nanofluids were measured. Nanoparticle concentrations were varied between 5 wt% and 50 wt%. Test results were found to be in excellent agreement with Model II, while the predictions of Model I deviated very significantly from the data. Therefore, Model II is recommended for nanofluids.

  8. Heat capacity, enthalpy and entropy of bismuth niobate and bismuth tantalate

    Czech Academy of Sciences Publication Activity Database

    Hampl, M.; Strejc, A.; Sedmidubský, D.; Růžička, K.; Hejtmánek, Jiří; Leitner, J.

    2006-01-01

    Roč. 179, - (2006), s. 77-80 ISSN 0022-4596 Institutional research plan: CEZ:AV0Z10100521 Keywords : heat capacity * heat of formation * heat content * bismuth perovskite Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.107, year: 2006

  9. Unprecedented Integral-Free Debye Temperature Formulas: Sample Applications to Heat Capacities of ZnSe and ZnTe

    Directory of Open Access Journals (Sweden)

    R. Pässler

    2017-01-01

    Full Text Available Detailed analytical and numerical analyses are performed for combinations of several complementary sets of measured heat capacities, for ZnSe and ZnTe, from the liquid-helium region up to 600 K. The isochoric (harmonic parts of heat capacities, CVh(T, are described within the frame of a properly devised four-oscillator hybrid model. Additional anharmonicity-related terms are included for comprehensive numerical fittings of the isobaric heat capacities, Cp(T. The contributions of Debye and non-Debye type due to the low-energy acoustical phonon sections are represented here for the first time by unprecedented, integral-free formulas. Indications for weak electronic contributions to the cryogenic heat capacities are found for both materials. A novel analytical framework has been constructed for high-accuracy evaluations of Debye function integrals via a couple of integral-free formulas, consisting of Debye’s conventional low-temperature series expansion in combination with an unprecedented high-temperature series representation for reciprocal values of the Debye function. The zero-temperature limits of Debye temperatures have been detected from published low-temperature Cp(T data sets to be significantly lower than previously estimated, namely, 270 (±3 K for ZnSe and 220 (±2 K for ZnTe. The high-temperature limits of the “true” (harmonic lattice Debye temperatures are found to be 317 K for ZnSe and 262 K for ZnTe.

  10. Theoretical study of the magnetic heat capacity of praseodymium metal

    International Nuclear Information System (INIS)

    Glenn, R.L.

    1976-01-01

    The heat capacity of praseodymium metal at low temperatures is calculated using a valence change model. The effect of the presence of a small temperature-dependent and field-dependent percentage of 4+ ions is computed using crystalfield techniques. Good agreement with the experimentally determined values is obtained for polycrystalline and single-crystal praseodymium in zero field and various other fields up to 30 koe. In addition, the effects of selected exchange models on the heat capacity and susceptibility are computed. The model is shown to be compatible with both the parallel and perpendicular susceptibilities

  11. Determination of Specific Heat Capacity on Composite Shape-Stabilized Phase Change Materials and Asphalt Mixtures by Heat Exchange System.

    Science.gov (United States)

    Ma, Biao; Zhou, Xue-Yan; Liu, Jiang; You, Zhanping; Wei, Kun; Huang, Xiao-Feng

    2016-05-19

    Previous research has shown that composite shape-stabilized phase change material (CPCM) has a remarkable capacity for thermal storage and stabilization, and it can be directly applied to highway construction without leakage. However, recent studies on temperature changing behaviors of CPCM and asphalt mixture cannot intuitively reflect the thermoregulation mechanism and efficiency of CPCM on asphalt mixture. The objective of this paper is to determine the specific heat capacity of CPCM and asphalt mixtures mixed with CPCM using the heat exchange system and the data acquisition system. Studies have shown that the temperature-rise curve of 5 °C CPCM has an obvious temperature plateau, while an asphalt mixture mixed with 5 °C CPCM does not; with increasing temperature, the specific heat capacities of both 5 °C CPCM and asphalt mixture first increase and then decrease, while the variation rate of 5 °C CPCM is larger than that of the asphalt mixture, and the maximum specific heat capacity of 5 °C CPCM appears around the initial phase change temperature. It is concluded that the temperature intervals of 5 °C CPCM are -18 °C-7 °C, 7 °C-25 °C and 25 °C-44 °C, respectively, and that of the asphalt mixture are -18 °C~10 °C, -10 °C~5 °C and 5 °C~28 °C. A low dosage of 5 °C CPCM has little influence on the specific heat capacity of asphalt mixture. Finally, the functions of specific heat capacities and temperature for CPCM and asphalt mixture mixed with CPCM were recommended by the sectional regression method.

  12. The heat capacity of polyethylene fibers measured by multi-frequency temperature-modulated calorimetry

    International Nuclear Information System (INIS)

    Pyda, M.; Nowak-Pyda, E.; Wunderlich, B.

    2006-01-01

    The apparent heat capacity of polyethylene fibers in the melting region was measured by quasi-isothermal, temperature-modulated differential scanning calorimetry (TMDSC) and compared with results from standard differential scanning calorimetry (DSC) and the solid and liquid thermodynamic heat capacity as references from the ATHAS Data Bank. Using a multi-frequency, complex sawtooth modulation in the quasi-isothermal mode disclosed for the first time that the uncorrected apparent heat capacity C p =A Φ /(A T s ω) of the liquid polyethylene fiber increases with increasing frequency (A Φ is the differential heat-flow rate and A T s is the sample temperature). The frequency-dependent heat capacity cannot be represented by the expression: C p =A Φ /(A T s νω)[1+(τνω) 2 ] 0.5 because of a negative τ 2 . The results were later confirmed by independent measurements on single sinusoidal quasi-isothermal TMDSC on the same material. The error is caused by shrinking of the fiber, which deforms the sample pan

  13. Estimation of work capacity of welded mounting joints of pipelines of heat resisting steel

    International Nuclear Information System (INIS)

    Gorynin, I.V.; Ignatov, V.A.; Timofeev, B.T.; Blyumin, A.A.

    1982-01-01

    The analysis of a work capacity of circular welds made for the Dsub(y)850 pipeline connection with high pressure vessels of heat resisting steel of the 15Kh1NMFA type has been carried out on the base of test results with small samples and real units. Welds were performed using the manual electric arc welding without the following heat treatment. It has been shown that residual stresses in such welds do not produce an essential effect on the resistance of weld metal and heat affected zone on the formation and developments of cracks

  14. Magnon heat capacity and magnetic susceptibility of the spin Lieb lattice

    Energy Technology Data Exchange (ETDEWEB)

    Yarmohammadi, Mohsen, E-mail: m.yarmohammadi69@gamil.com

    2016-11-01

    Using linear response theory, Heisenberg model Hamiltonian and Green's function technique, the influences of Dzyaloshinskii–Moriya interaction (DMI), external magnetic field and next-nearest-neighbor (NNN) coupling on the density of magnon modes (DMM), the magnetic susceptibility (MS) and the magnon heat capacity (MHC) of a spin Lieb lattice, a face-centered square lattice, are investigated. The results reveal a band gap in the DMM and we witness an extension in the bandwidth and an increase in the number of van-Hove singularities as well. As a notable point, besides the magnetic nature which includes ferromagnetism in spin Lieb-based nanosystems, MS is investigated. Further, we report a Schottky anomaly in the MHC. The results show that the effects of the magnetic field on the MHC and MS have different behaviors in two temperature regions. In the low temperature region, MHC and MS increase when the magnetic field strength increases. On the other hand, the MHC and MS reduce with increasing the magnetic field strength in the high temperature region. Also comprehensive numerical modelling of the DMM, the MS and the MHC of a spin Lieb lattice yields excellent qualitative agreement with the experimental data. - Highlights: • Theoretical calculation of density of states of the spin Lieb lattice. • The investigation of the effect of external magnetic field on the magnon heat capacity and magnetic susceptibility. • The investigation of the effect of NNN coupling and the DMI strength on the magnon heat capacity and magnetic susceptibility.

  15. Heat capacity of NdB.sub.6./sub..

    Czech Academy of Sciences Publication Activity Database

    Reiffers, M.; Šebek, Josef; Šantavá, Eva; Shitsevalova, N.; Gabáni, S.; Pristáš, G.; Flachbart, K.

    2007-01-01

    Roč. 310, - (2007), e595-e597 ISSN 0304-8853 Institutional research plan: CEZ:AV0Z10100520 Keywords : heat capacity * NdB 6 * magnetic contribution Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 1.704, year: 2007

  16. Transient convective heat transfer to laminar flow from a flat plate with constant heat capacity

    International Nuclear Information System (INIS)

    Hanawa, Juichi

    1980-01-01

    Most basic transient heat transfer problem is the transient response characteristics of forced convection heat transfer in the flow along a flat plate or in a tube. In case of the laminar flow along a flat plate, the profile method using steady temperature distribution has been mostly adopted, but its propriety has not been clarified yet. About the unsteady heat transfer in the laminar flow along a flat plate, the analysis or experiment evaluating the heat capacity of the flat plate exactly was never carried out. The purpose of this study is to determine by numerical calculation the unsteady characteristics of the boundary layer in laminar flow and to confirm them by experiment concerning the unsteady heat transfer when a flat plate with a certain heat capacity is placed in parallel in uniform flow and given a certain quantity of heat generation suddenly. The basic equation and the solution are given, and the method of numerical calculation and the result are explained. The experimental setup and method, and the experimental results are shown. Both results were in good agreement, and the response of wall temperature, the response of Nusselt number and the change of temperature distribution in course of time were able to be determined by applying Laplace transformation and numerical Laplace inverse transformation to the equation. (Kako, I.)

  17. Environmentally friendly and highly productive bi-component melt spinning of thermoregulated smart polymer fibres with high latent heat capacity

    Directory of Open Access Journals (Sweden)

    Ch. Cherif

    2018-03-01

    Full Text Available A stable and reproducible bi-component melt spinning process on an industrial scale incorporating Phase Change Material (PCM into textile fibres has been successfully developed and carried out using a melt spinning machine. The key factor for a successful bi-component melt spinning process is that a deep insight into the thermal and rheological behaviour of PCM using Difference Scanning Calorimetry (DSC, Thermogravimetric Analysis (TGA, and an oscillatory rheological investigation. PCM is very sensitive to the temperature and residence time of the melt spinning process. It is found that the optimal process temperature of PCM is 210 °C. The textile-physical properties and the morphology of the melt spun and further drawn bi-component core and sheath fibres (bico fibres were investigated and interpreted. The heat capacities of PCM incorporated in bico fibres were also determined by means of DSC. The melt spun bico fibres integrating PCM provide a high latent heat of up to 22 J/g, which is three times higher than that of state-of-the-art fibres, which were also obtained using the melt spinning process. Therefore, they have the potential to be used as smart polymer fibres for textile and other technical applications.

  18. Heat capacity of the neutron star inner crust within an extended nuclear statistical equilibrium model

    Science.gov (United States)

    Burrello, S.; Gulminelli, F.; Aymard, F.; Colonna, M.; Raduta, Ad. R.

    2015-11-01

    Background: Superfluidity in the crust is a key ingredient for the cooling properties of proto-neutron stars. Present theoretical calculations employ the quasiparticle mean-field Hartree-Fock-Bogoliubov theory with temperature-dependent occupation numbers for the quasiparticle states. Purpose: Finite temperature stellar matter is characterized by a whole distribution of different nuclear species. We want to assess the importance of this distribution on the calculation of heat capacity in the inner crust. Method: Following a recent work, the Wigner-Seitz cell is mapped into a model with cluster degrees of freedom. The finite temperature distribution is then given by a statistical collection of Wigner-Seitz cells. We additionally introduce pairing correlations in the local density BCS approximation both in the homogeneous unbound neutron component, and in the interface region between clusters and neutrons. Results: The heat capacity is calculated in the different baryonic density conditions corresponding to the inner crust, and in a temperature range varying from 100 KeV to 2 MeV. We show that accounting for the cluster distribution has a small effect at intermediate densities, but it considerably affects the heat capacity both close to the outer crust and close to the core. We additionally show that it is very important to consider the temperature evolution of the proton fraction for a quantitatively reliable estimation of the heat capacity. Conclusions: We present the first modelization of stellar matter containing at the same time a statistical distribution of clusters at finite temperature, and pairing correlations in the unbound neutron component. The effect of the nuclear distribution on the superfluid properties can be easily added in future calculations of the neutron star cooling curves. A strong influence of resonance population on the heat capacity at high temperature is observed, which deserves to be further studied within more microscopic calculations.

  19. Heat capacity and magnetocaloric effect in polycrystalline Gd 1-xSm xMn 2Si 2

    Science.gov (United States)

    Kumar, Pramod; Singh, Niraj K.; Suresh, K. G.; Nigam, A. K.; Malik, S. K.

    2007-12-01

    We report the magnetocaloric effect in terms of isothermal magnetic entropy change as well as adiabatic temperature change, calculated using the heat capacity data. Using the zero-field heat capacity data, the magnetic contribution to the heat capacity has been estimated. The variations in the magnetocaloric behavior have been explained on the basis of the magnetic structure of these compounds. The refrigerant capacities have also been calculated for these compounds.

  20. Heat capacities of aqueous polar aromatic compounds over a wide range of conditions. Part I: phenol, cresols, aniline, and toluidines

    International Nuclear Information System (INIS)

    Censky, Miroslav; Hnedkovsky, Lubomir; Majer, Vladimir

    2005-01-01

    The heat capacities of dilute aqueous solutions of phenol (hydroxybenzene), three cresols (2-, 3- and 4-methylhydroxybenzene), aniline (aminobenzene) and three toluidines (2-, 3- and 4-methylaminobenzene) were determined using a modified flow Picker-type high temperature calorimeter. The measurements were performed at temperatures between (303 and 623) K or 573 K for compounds containing hydroxy or amino group, respectively, and at several pressures up to 30 MPa. Standard heat capacities (partial molar heat capacities at infinite dilution) obtained from the experimental data exhibit a strong increase with temperature above 500 K consistent with the evolution of the standard volumes reported earlier. The data for aqueous phenol were used for testing several semiempiric models proposed for description of the standard thermodynamic properties of aqueous solutes. Their ability to reproduce the temperature and pressure dependence of standard heat capacities and to extrapolate towards higher conditions were examined

  1. Final Report: Cooling Seasonal Energy and Peak Demand Impacts of Improved Duct Insulation on Fixed-Capacity (SEER 13) and Variable-Capacity (SEER 22) Heat Pumps

    Energy Technology Data Exchange (ETDEWEB)

    Withers, C. [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States); Florida Solar Energy Center (FSEC), Cocoa, FL (United States); Cummings, J. [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States); Florida Solar Energy Center (FSEC), Cocoa, FL (United States); Nigusse, B. [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States); Florida Solar Energy Center (FSEC), Cocoa, FL (United States)

    2016-09-01

    A new generation of full variable-capacity, central, ducted air-conditioning (AC) and heat pump units has come on the market, and they promise to deliver increased cooling (and heating) efficiency. They are controlled differently than standard single-capacity (fixed-capacity) systems. Instead of cycling on at full capacity and then cycling off when the thermostat is satisfied, they can vary their capacity over a wide range (approximately 40% to 118% of nominal full capacity), thus staying “on” for up to twice as many hours per day compared to fixed-capacity systems of the same nominal capacity. The heating and cooling capacity is varied by adjusting the indoor fan air flow rate, compressor, and refrigerant flow rate as well as the outdoor unit fan air flow rate. Note that two-stage AC or heat pump systems were not evaluated in this research effort. The term dwell is used to refer to the amount of time distributed air spends inside ductwork during space-conditioning cycles. Longer run times mean greater dwell time and therefore greater exposure to conductive gains and losses.

  2. Final Report: Cooling Seasonal Energy and Peak Demand Impacts of Improved Duct Insulation on Fixed-Capacity (SEER 13) and Variable-Capacity (SEER 22) Heat Pumps

    Energy Technology Data Exchange (ETDEWEB)

    Withers, C. [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States); Florida Solar Energy Center, Cocoa, FL (United States); Cummings, J. [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States); Florida Solar Energy Center, Cocoa, FL (United States); Nigusse, B. [Building America Partnership for Improved Residential Construction, Cocoa, FL (United States); Florida Solar Energy Center, Cocoa, FL (United States)

    2016-09-08

    A new generation of full variable-capacity, central, ducted air-conditioning (AC) and heat pump units has come on the market, and they promise to deliver increased cooling (and heating) efficiency. They are controlled differently than standard single-capacity (fixed-capacity) systems. Instead of cycling on at full capacity and then cycling off when the thermostat is satisfied, they can vary their capacity over a wide range (approximately 40% to 118% of nominal full capacity), thus staying “on” for up to twice as many hours per day compared to fixed-capacity systems of the same nominal capacity. The heating and cooling capacity is varied by adjusting the indoor fan air flow rate, compressor, and refrigerant flow rate as well as the outdoor unit fan air flow rate. Note that two-stage AC or heat pump systems were not evaluated in this research effort. The term dwell is used to refer to the amount of time distributed air spends inside ductwork during space-conditioning cycles. Longer run times mean greater dwell time and therefore greater exposure to conductive gains and losses.

  3. Enhanced specific heat capacity of molten salt-based nanomaterials: Effects of nanoparticle dispersion and solvent material

    International Nuclear Information System (INIS)

    Jo, Byeongnam; Banerjee, Debjyoti

    2014-01-01

    This study investigated the effect of nanoparticle dispersion on the specific heat capacity for carbonate salt mixtures doped with graphite nanoparticles. The effect of the solvent material was also examined. Binary carbonate salt mixtures consisting of lithium carbonate and potassium carbonate were used as the base material for the graphite nanomaterial. The different dispersion uniformity of the nanoparticles was created by employing two distinct synthesis protocols for the nanomaterial. Different scanning calorimetry was employed to measure the specific heat capacity in both solid and liquid phases. The results showed that doping the molten salt mixture with the graphite nanoparticles significantly raised the specific heat capacity, even in minute concentrations of graphite nanoparticles. Moreover, greater enhancement in the specific heat capacity was observed from the nanomaterial samples with more homogeneous dispersion of the nanoparticles. A molecular dynamics simulation was also performed for the nanomaterials used in the specific heat capacity measurements to explain the possible mechanisms for the enhanced specific heat capacity, including the compressed layering and the species concentration of liquid solvent molecules

  4. The effect of molybdenum content with changes in phase and heat capacity of UMo alloy

    International Nuclear Information System (INIS)

    Aslina Br Ginting; Supardjo; Agoeng Kadarjono; Dian Anggraini

    2011-01-01

    Has done the analysis of phase and heat capacity change of the UMo alloy by variation of 7% Mo, 8% and 9% Mo. Analysis performed using phase change Differential Thermal Analysis (DTA) at a temperature between 30°C until 1400°C with heating rate 10°C/minute and heat capacity analysis carried out using Differential Scanning Calorimetry (DSC) at a temperature between 30°C to 450°C with heating rate 5°C/minute. The purpose of this study was to determine the character of the UMo alloy include phase change and heat capacity variation with Mo content due to higher content of Mo is expected to change both the character U-7% Mo alloy, U-8% Mo and U-9% Mo. The analysis showed that of 7% Mo, 8% Mo and 9% Mo the combination experiencing α+ δ a phase change becomes α + β phase at temperatures of 578.63°C to 580.16°C. At the temperature 606.50°C to 627.58°C having a phase change of α+ β to β + γ be followed by the endothermic reaction in the content of 9% Mo with the enthalpy ΔH = 6.5989 J / g. At temperatures 1075.45°C up to 1160.51°C phase change β + γ into γ phase. The increase in Mo content to heating at a temperature 1100°C not cause a significant phase change. At temperatures above 1177.21°C, the increase in Mo content leads to changes in the γ phase of forming L + γ phase which followed the reaction of uranium with Mo to form γ phase - solid solution. The higher content of Mo, the reaction heat is needed and released the greater. The results of the analysis of the heat capacity is obtained that the increase in Mo content in the U-7% Mo, U-8% Mo, and U-9% Mo alloy does not give a significant difference in heat capacity. This is attested by doing different test (F test) at 95% degree of confidence. This data is expected to be as a first step to study the manufacture of UMo alloy as a fuel of high uranium density for research reactor. (author)

  5. Evaluation of the quasi-isothermal method of modulated DSC for heat capacity measurement

    International Nuclear Information System (INIS)

    Venkata Krishnan, R.; Nagarajan, K.

    2004-01-01

    Heat capacity measurements were carried out on ThO 2 by Modulated Differential Scanning Calorimetry (MDSC) using quasi-isothermal method in the temperature range 323-723 K. The highest accuracy of the heat capacity data obtained by this method was ± 2-3% which is much lower than that reported in the literature. (author)

  6. Low-temperature heat capacity and thermodynamic functions of vitamin B{sub 12}

    Energy Technology Data Exchange (ETDEWEB)

    Knyazev, A.V., E-mail: knyazevav@gmail.com; Smirnova, N.N.; Plesovskikh, A.S.; Shushunov, A.N.; Knyazeva, S.S.

    2014-04-01

    Graphical abstract: - Highlights: • Temperature dependence of heat capacity of vitamin B{sub 12} has been measured by precision adiabatic vacuum calorimetry. • The thermodynamic functions of the vitamin B{sub 12} have been determined for the range from T → 0 to 343 K. • The character of heterodynamics of structure was detected. • The thermal stability of cyanocobalamin was studied by differential scanning calorimetry. - Abstract: In the present work temperature dependence of heat capacity of vitamin B{sub 12} (cyanocobalamin) has been measured for the first time in the range from 6 to 343 K by precision adiabatic vacuum calorimetry. Based on the experimental data, the thermodynamic functions of the vitamin B{sub 12}, namely, the heat capacity, enthalpy H°(T) − H°(0), entropy S°(T) − S°(0) and Gibbs function G°(T) − H°(0) have been determined for the range from T → 0 to 343 K. The value of the fractal dimension D in the function of multifractal generalization of Debye's theory of the heat capacity of solids was estimated and the character of heterodynamics of structure was detected. The thermal stability of cyanocobalamin was also studied by differential scanning calorimetry.

  7. Heat capacity measurements on ThO2 by temperature modulated differential scanning calorimetry (TMDSC)

    International Nuclear Information System (INIS)

    Venkatakrishnan, R.; Nagarajan, K.; Vasudeva Rao, P.R.

    2001-01-01

    Heat capacity measurements were carried out on ThO 2 in the temperature range 330-820 K by using temperature modulated DSC. An underlying heating rate of 5 K. min -1 , a temperature modulation with an amplitude of 0.398K and a period of 150s were used for these measurements. The heat capacity values are within ± 2-4% of the literature data. (author)

  8. Low temperature heat capacities and thermodynamic functions described by Debye-Einstein integrals.

    Science.gov (United States)

    Gamsjäger, Ernst; Wiessner, Manfred

    2018-01-01

    Thermodynamic data of various crystalline solids are assessed from low temperature heat capacity measurements, i.e., from almost absolute zero to 300 K by means of semi-empirical models. Previous studies frequently present fit functions with a large amount of coefficients resulting in almost perfect agreement with experimental data. It is, however, pointed out in this work that special care is required to avoid overfitting. Apart from anomalies like phase transformations, it is likely that data from calorimetric measurements can be fitted by a relatively simple Debye-Einstein integral with sufficient precision. Thereby, reliable values for the heat capacities, standard enthalpies, and standard entropies at T  = 298.15 K are obtained. Standard thermodynamic functions of various compounds strongly differing in the number of atoms in the formula unit can be derived from this fitting procedure and are compared to the results of previous fitting procedures. The residuals are of course larger when the Debye-Einstein integral is applied instead of using a high number of fit coefficients or connected splines, but the semi-empiric fit coefficients keep their meaning with respect to physics. It is suggested to use the Debye-Einstein integral fit as a standard method to describe heat capacities in the range between 0 and 300 K so that the derived thermodynamic functions are obtained on the same theory-related semi-empiric basis. Additional fitting is recommended when a precise description for data at ultra-low temperatures (0-20 K) is requested.

  9. Effect of crystalline electric field on heat capacity of LnBaCuFeO5 (Ln = Gd, Ho, Yb)

    Science.gov (United States)

    Lal, Surender; Mukherjee, K.; Yadav, C. S.

    2018-02-01

    Structural, magnetic and thermodynamic properties of layered perovskite compounds LnBaCuFeO5 (Ln = Ho, Gd, Yb) have been investigated. Unlike the iso-structural compound YBaCuFeO5, which shows commensurate antiferromagnetic to incommensurate antiferromagnetic ordering below ∼200 K, the studied compounds do not show any magnetic transition in measured temperature range of 2-350 K. The high temperature heat capacity of the compounds is understood by employing contributions from both optical and acoustic phonons. At low temperature, the observed upturn in the heat capacity is attributed to the Schottky anomaly. The magnetic field dependent heat capacity shows the variation in position of the anomaly with temperature, which appears due to the removal of ground state degeneracy of the rare earth ions, by the crystalline electric field.

  10. Predictive model for the heat capacity of ionic liquids using the mass connectivity index

    International Nuclear Information System (INIS)

    Valderrama, Jose O.; Martinez, Gwendolyn; Rojas, Roberto E.

    2011-01-01

    A simple and accurate model to predict the heat capacity of ionic liquids is presented. The proposed model considers variables readily available for ionic liquids and that have important effect on heat capacity, according to the literature information. Additionally a recently defined structural parameter known as mass connectivity index is incorporated into the model. A set of 602 heat capacity data for 146 ionic liquids have been used in the study. The results were compared with experimental data and with values reported by other available estimation methods. Results show that the new simple correlation gives low deviations and can be used with confidence in thermodynamic and engineering calculations.

  11. Heat capacity of the white pine biocarbon preform and the related biocarbon/copper composite

    Science.gov (United States)

    Smirnov, I. A.; Orlova, T. S.; Smirnov, B. I.; Wlosewicz, D. W.; Misiorek, H.; Jezowski, A.; Wilkes, T. E.; Faber, K. T.

    2009-11-01

    This paper reports on measurements in the 80-300-K temperature interval of the heat capacity at constant pressure C p ( T) of high-porosity amorphous white pine carbon preforms (biocarbon) prepared by pyrolysis (carbonization) at T carb = 1000 and 2400°C in an argon flow. The dependences C p ( T) for biocarbon/copper composites based on the carbon preforms obtained have also been determined. It is shown that the mixture rule holds for the composites, i.e., that C p ( T) of the composite is a sum of the heat capacities of the constituent materials taken in the corresponding ratios. Phonon mean free paths for the white pine carbon preforms prepared at T carb = 1000 and 2400°C have been calculated and used to estimate the size of the nanocrystallites contributing to formation of the carbon frameworks of these preforms.

  12. Measurement of the specific heat capacity of graphite

    Energy Technology Data Exchange (ETDEWEB)

    Picard, S.; Burns, D.T.; Roger, P

    2006-01-15

    With the objective of implementing graphite calorimetry at the BIPM to measure absorbed dose, an experimental assembly has recently been constructed to measure the specific heat capacity of graphite. A status description of the apparatus and results from the first measurements are given. The outcome is discussed and the experimental uncertainty is reviewed. (authors)

  13. Measurement of the specific heat capacity of graphite

    International Nuclear Information System (INIS)

    Picard, S.; Burns, D.T.; Roger, P.

    2006-01-01

    With the objective of implementing graphite calorimetry at the BIPM to measure absorbed dose, an experimental assembly has recently been constructed to measure the specific heat capacity of graphite. A status description of the apparatus and results from the first measurements are given. The outcome is discussed and the experimental uncertainty is reviewed. (authors)

  14. Low-temperature heat-capacity study of the U6X (XequivalentMn, Fe, Co, Ni) compounds

    International Nuclear Information System (INIS)

    Yang, K.N.; Maple, M.B.; DeLong, L.E.; Huber, J.G.; Junod, A.

    1989-01-01

    Measurements of the superconducting- and normal-state heat capacity of U 6 X (XequivalentMn, Fe, Co, Ni) compounds have been performed over a temperature range 1 Kapprox. 6 X compounds have strong renormalizations of the free-carrier effective mass m/sup */ in the range 10m/sub e/approx. 6 X heat capacities suggest the presence of high densities of low-energy excitations of undetermined nature. The results are analyzed in terms of models appropriate to heavy-fermion liquids, and anisotropic or strong-coupled superconductors. The U 6 X compounds form a link between relatively low-m/sup */, high-transition-temperature A15 compounds and the more extreme examples of heavy-fermion superconductors such as UBe/sub 13/, UPt 3 , and CeCuSi 2 for which m/sup */∼10 2 m/sub e/. .AE

  15. Apparent heat capacity measurements and thermodynamic functions of D(−)-fructose by standard and temperature-modulated calorimetry

    International Nuclear Information System (INIS)

    Magoń, A.; Pyda, M.

    2013-01-01

    Highlights: ► Experimental, apparent heat capacity of fructose was investigated by advanced thermal analysis. ► Equilibrium melting parameters of fructose were determined. ► Decomposition, superheating of crystalline fructose during melting process were presented. ► TGA, DSC, and TMDSC are useful tools for characterisation of fructose. - Abstract: The qualitative and quantitative thermal analyses of crystalline and amorphous D(−)-fructose were studied utilising methods of standard differential scanning calorimetry (DSC), quasi-isothermal temperature-modulated differential scanning calorimetry (quasi-isothermal TMDSC), and thermogravimetric analysis (TGA). Advanced thermal analysis of fructose was performed based on heat capacity. The apparent total and apparent reversing heat capacities, as well as phase transition parameters were examined on heating and cooling. The melting temperature, T m , of crystalline D(−)-fructose shows a heating rate dependency, which increases with raising the heating rate and leads to superheating. The equilibrium melting temperatures: T m ∘ (onset) = 370 K and T m ∘ (peak) = 372 K, and the equilibrium enthalpy of fusion Δ fus H ° = 30.30 kJ · mol −1 , of crystalline D(−)-fructose were estimated on heating for the results at zero heating rate. Anomalies in the heat capacity in the liquid state of D(−)-fructose, assigned as possible tautomerisation equilibrium, were analysed by DSC and quasi-isothermal TMDSC, both on heating and cooling. Thermal stability of crystals in the region of the melting temperature was examined by TGA and quasi-isothermal TMDSC. Melting, mutarotation, and degradation processes occur simultaneously and there are differences in values of the liquid heat capacity of D(−)-fructose with varied thermal history, measured by quasi-isothermal TMDSC. Annealing of amorphous D(−)-fructose between the glass transition temperature, T g , and the melting temperature, T m , also leads to

  16. Specific heat capacities of different clayey samples obtained by differential scanning calorimetry

    International Nuclear Information System (INIS)

    Fernandez, A.M.

    2012-01-01

    Document available in extended abstract form only. The thermo-physical properties allow to calculate heat flows and to determine the thermal behaviour of the materials. Temperature influences the rates of the physical, chemical and biological reactions and processes in the soil or a material. Variations in temperature and water content in thermal, hydraulic, mechanical and geochemical processes affect the thermal properties such as density, specific heat, thermal conductivity and thermal diffusivity. Therefore, mathematical models that describe the dependence of the thermal properties on temperature and concentration are of interest to be used in computational programs applied to the modelling of coupled thermo-mechanical-hydraulic and chemical (THMC) processes. In this work, the specific heat capacity of different clayey international reference materials was determined. Differential Scanning Calorimetry (DSC) was used for such purpose. DSC is the main tool for determining the specific heat capacities of materials as a function of temperature. The specific heat capacity, c p (J/Kg.K), is a measurement of the amount of heat required to raise the temperature of a unit mass of a substance by one unit of temperature. A change in temperature, caused by a gain or a loss of heat from a material, depends on the specific heat capacity of the material. Thus, the specific heat capacity is a key and characteristic property of a material and/or substance, which should be determine accurately. The specific heat capacity is an intensive property and, unlike the thermal conductivity and thermal diffusivity, is independent of the dry density of the material. C p of the solid samples was determined by using a SETSYS Evolution 16 thermal analyser coupled to a differential scanning calorimeter (TG-DSC-DTA) from SETARAM Instrumentation. The thermal analyser system can use a heating rate from 0.01 to 100 C/min under a dynamic argon atmosphere and temperatures ranging from ambient to

  17. The low-temperature heat capacities of Tb, Lu and Y

    International Nuclear Information System (INIS)

    Wells, P.; Lanchester, P.C.; Jones, D.W.; Jordan, R.G.

    1976-01-01

    The heat capacities of Tb, Lu and Y, refined by solid state electro-transport processing have been measured between 1.5 and 16 K. Below 4 K the results were fitted to the expression C = γT + AT 3 where for Tb the nuclear and magnetic contributions were first calculated and subtracted from the total heat capacity. The resultant values of γ(mJ mol -1 K -2 ) and limiting Debye temperatures thetasub(D) (T → 0) were as follows. Tb: γ = 4.4 +- 0.1, thetasub(D) = 178 +- 2 K; Lu: γ = 6.8 +- 0.1, thetasub(D) 205 +- 3 K; Y: γ = 8.2 +- 0.1, thetasub(D) = 248 +- 3 K. The Debye temperature was found in all instances to decrease by about 10% between 4 and 16 K. (author)

  18. Low temperature heat capacity of scandium and alloys of scandium

    Energy Technology Data Exchange (ETDEWEB)

    Tsang, T. W.E.

    1977-12-01

    The heat capacity of three electrotransport purified scandium samples has been measured from 1 to 20/sup 0/K. The resultant electronic specific heat constant and Debye temperature are 10.337 +- 0.015 mJ/gm-atom K/sup 2/ and 346.7 +- 0.8/sup 0/K respectively, and these values are believed to be truly representative of intrinsic scandium. Alloying studies have also been carried out to investigate the band structure of scandium based on the rigid band model, with zirconium to raise the electron concentration and magnesium to lower it. The results are then compared to the theoretical band structure calculations. Low temperature heat capacity measurements have also been made on some dilute Sc-Fe alloys. An anomaly is observed in the C/T vs. T/sup 2/ plot, but the C vs. T curve shows no evidence of magnetic ordering down to 1/sup 0/K, and electrical resistance measurement from 4 to 0.3/sup 0/K also indicates that no magnetic ordering took place.

  19. Computer calculation of heat capacity of natural gases over a wide range of pressure and temperature

    Energy Technology Data Exchange (ETDEWEB)

    Dranchuk, P.M. (Alberta Univ., Edmonton, AB (Canada)); Abou-Kassem, J.H. (Pennsylvania State Univ., University Park, PA (USA))

    1992-04-01

    A method is presented whereby specific heats or heat capacities of natural gases, both sweet and sour, at elevated pressures and temperatures may be made suitable to modern-day machine calculation. The method involves developing a correlation for ideal isobaric heat capacity as a function of gas gravity and pseudo reduced temperature over the temperature range of 300 to 1500 K, and a mathematical equation for the isobaric heat capacity departure based on accepted thermodynamic principles applied to an equation of state that adequately describes the behavior of gases to which the Standing and Katz Z factor correlation applies. The heat capacity departure equation is applicable over the range of 0.2 {le} Pr {le} 15 and 1.05 {le} Tr {le} 3, where Pr and Tr refer to the reduced pressure and temperature respectively. The significance of the method presented lies in its utility and adaptability to computer applications. 25 refs., 2 figs., 4 tabs.

  20. Standard molar volumes and heat capacities of aqueous solutions of sodium trifluoromethanesulfonate at temperatures up to 573 K and pressures to 28 MPa

    International Nuclear Information System (INIS)

    Pourtier, Emilie; Ballerat-Busserolles, Karine; Majer, Vladimir; Šedlbauer, Josef

    2013-01-01

    Highlights: ► Original HT/HP data for NaTr(aq) obtained using non-commercial instruments. ► First heat capacity data for NaTr(aq) at conditions remote from ambient. ► Correction for association when calculating stand. therm. properties of Tr(aq) anion. - Abstract: Densities and heat capacities of aqueous solutions of sodium trifluoromethanesulfonate (sodium triflate) of concentrations from 0.025 to 0.3 mol · kg −1 were measured with high temperature, high pressure custom-made instruments at temperatures up to 573 K and at pressures up to 28 MPa. Standard molar volumes and standard molar heat capacities were obtained via extrapolation of the apparent molar properties to infinite dilution. The results for volumetric properties are consistent with earlier literature data, but no previous measurements exist for heat capacities of sodium triflate at superambient conditions. The new data were used for calculating the standard molar volumes and heat capacities for the triflate anion and compared with the results for triflic acid that should be essentially identical within the expected error margins. At temperatures above 473 K an effort was made to refine the processing of literature data for HCl(aq), taking into account its partial association, and subsequently to modify the value for Na + ion calculated from the standard thermodynamic values of NaCl(aq) where its ion pairing was already considered. This approach yields reasonable agreement at high temperatures between the values for triflate ion calculated from its salt and those for triflic acid.

  1. Modeling conductive heat transfer during high-pressure thawing processes: determination of latent heat as a function of pressure.

    Science.gov (United States)

    Denys, S; Van Loey, A M; Hendrickx, M E

    2000-01-01

    A numerical heat transfer model for predicting product temperature profiles during high-pressure thawing processes was recently proposed by the authors. In the present work, the predictive capacity of the model was considerably improved by taking into account the pressure dependence of the latent heat of the product that was used (Tylose). The effect of pressure on the latent heat of Tylose was experimentally determined by a series of freezing experiments conducted at different pressure levels. By combining a numerical heat transfer model for freezing processes with a least sum of squares optimization procedure, the corresponding latent heat at each pressure level was estimated, and the obtained pressure relation was incorporated in the original high-pressure thawing model. Excellent agreement with the experimental temperature profiles for both high-pressure freezing and thawing was observed.

  2. Deuterium isotope differences in 2-propanone (CH3)2CO/(CD3)2CO: a high-pressure sound-speed, density, and heat capacities study

    International Nuclear Information System (INIS)

    Szydlowski, J.; Gomes de Azevedo, R.; Rebelo, L.P.N.; Esperanca, J.M.S.S.; Guedes, H.J.R.

    2005-01-01

    A new high-pressure, non-intrusive ultrasonic microcell [J. Chem. Thermodyn. 36 (2004) 211-222] was used to carry out sound-speed measurements in deuteriated 2-propanone (acetone-d 6 ) in broad ranges of temperature (288 6 . (p, ρ, T) data for acetone-d 6 were also determined but in a narrower T, p range (298 to 333 K; 0.1 to 60 MPa). In this interval, several thermodynamic properties were thus determined, such as: isentropic (κ s ) and isothermal (κ T ) compressibility, isobaric thermal expansivity (α p ), isobaric (c p ) and isochoric (c v ) specific heat capacity, and the thermal pressure coefficient (γ v ). Comparisons with our data for acetone-h 6 enabled us to establish the magnitude and sign of deuterium isotope effects for identical properties. These effects are a consequence of distinct vibrational mode frequencies in an isotope-invariant force constants' field. Molar heat capacities and their isotope effects were theoretically determined by employing an Einstein-like model for the vibrational frequencies of acetone-h 6 and acetone-d 6

  3. Heat pumps in district heating networks

    DEFF Research Database (Denmark)

    Ommen, Torben Schmidt; Markussen, Wiebke Brix; Elmegaard, Brian

    constraints limit the power plants. Efficient heat pumps can be used to decouple the constraints of electricity and heat production, while maintaining the high energy efficiency needed to match the politically agreed carbon emission goals. The requirements in terms of COP, location, capacity and economy...... and strategic planning in the energy sector. The paper presents a case study of optimal implementation of heat pumps in the present energy system of the Copenhagen area. By introduction of the correct capacity of heat pumps, a 1,6 % reduction in fuel consumption for electricity and heat production can...

  4. Model study on steady heat capacity in driven stochastic systems

    Czech Academy of Sciences Publication Activity Database

    Pešek, Jiří; Boksenbojm, E.; Netočný, Karel

    2012-01-01

    Roč. 10, č. 3 (2012), 692-701 ISSN 1895-1082 Institutional research plan: CEZ:AV0Z10100520 Keywords : nonequilibrium steady state * quasistatic process * heat capacity Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 0.905, year: 2012

  5. Electrolytic conductivity and molar heat capacity of two aqueous solutions of ionic liquids at room-temperature: Measurements and correlations

    International Nuclear Information System (INIS)

    Lin Peiyin; Soriano, Allan N.; Leron, Rhoda B.; Li Menghui

    2010-01-01

    As part of our systematic study on physicochemical characterization of ionic liquids, in this work, we report new measurements of electrolytic conductivity and molar heat capacity for aqueous solutions of two 1-ethyl-3-methylimidazolium-based ionic liquids, namely: 1-ethyl-3-methylimidazolium dicyanamide and 1-ethyl-3-methylimidazolium 2-(2-methoxyethoxy) ethylsulfate, at normal atmospheric condition and for temperatures up to 353.2 K. The electrolytic conductivity and molar heat capacity were measured by a commercial conductivity meter and a differential scanning calorimeter (DSC), respectively. The estimated experimental uncertainties for the electrolytic conductivity and molar heat capacity measurements were ±1% and ±2%, respectively. The property data are reported as functions of temperature and composition. A modified empirical equation from another researcher was used to correlate the temperature and composition dependence of the our electrolytic conductivity results. An excess molar heat capacity expression derived using a Redlich-Kister type equation was used to represent the temperature and composition dependence of the measured molar heat capacity and calculated excess molar heat capacity of the solvent systems considered. The correlations applied represent the our measurements satisfactorily as shown by an acceptable overall average deviation of 6.4% and 0.1%, respectively, for electrolytic conductivity and molar heat capacity.

  6. High Efficiency Heat Exchanger for High Temperature and High Pressure Applications

    Energy Technology Data Exchange (ETDEWEB)

    Sienicki, James J. [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Lv, Qiuping [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division; Moisseytsev, Anton [Argonne National Lab. (ANL), Argonne, IL (United States). Nuclear Engineering Division

    2017-09-29

    CompRex, LLC (CompRex) specializes in the design and manufacture of compact heat exchangers and heat exchange reactors for high temperature and high pressure applications. CompRex’s proprietary compact technology not only increases heat exchange efficiency by at least 25 % but also reduces footprint by at least a factor of ten compared to traditional shell-and-tube solutions of the same capacity and by 15 to 20 % compared to other currently available Printed Circuit Heat Exchanger (PCHE) solutions. As a result, CompRex’s solution is especially suitable for Brayton cycle supercritical carbon dioxide (sCO2) systems given its high efficiency and significantly lower capital and operating expenses. CompRex has already successfully demonstrated its technology and ability to deliver with a pilot-scale compact heat exchanger that was under contract by the Naval Nuclear Laboratory for sCO2 power cycle development. The performance tested unit met or exceeded the thermal and hydraulic specifications with measured heat transfer between 95 to 98 % of maximum heat transfer and temperature and pressure drop values all consistent with the modeled values. CompRex’s vision is to commercialize its compact technology and become the leading provider for compact heat exchangers and heat exchange reactors for various applications including Brayton cycle sCO2 systems. One of the limitations of the sCO2 Brayton power cycle is the design and manufacturing of efficient heat exchangers at extreme operating conditions. Current diffusion-bonded heat exchangers have limitations on the channel size through which the fluid travels, resulting in excessive solid material per heat exchanger volume. CompRex’s design allows for more open area and shorter fluid proximity for increased heat transfer efficiency while sustaining the structural integrity needed for the application. CompRex is developing a novel improvement to its current heat exchanger design where fluids are directed to alternating

  7. Thermodynamic performance analysis of sequential Carnot cycles using heat sources with finite heat capacity

    International Nuclear Information System (INIS)

    Park, Hansaem; Kim, Min Soo

    2014-01-01

    The maximum efficiency of a heat engine is able to be estimated by using a Carnot cycle. Even though, in terms of efficiency, the Carnot cycle performs the role of reference very well, its application is limited to the case of infinite heat reservoirs, which is not that realistic. Moreover, considering that one of the recent key issues is to produce maximum work from low temperature and finite heat sources, which are called renewable energy sources, more advanced theoretical cycles, which can present a new standard, and the research about them are necessary. Therefore, in this paper, a sequential Carnot cycle, where multiple Carnot cycles are connected in parallel, is studied. The cycle adopts a finite heat source, which has a certain initial temperature and heat capacity, and an infinite heat sink, which is assumed to be ambient air. Heat transfer processes in the cycle occur with the temperature difference between a heat reservoir and a cycle. In order to resolve the heat transfer rate in those processes, the product of an overall heat transfer coefficient and a heat transfer area is introduced. Using these conditions, the performance of a sequential Carnot cycle is analytically calculated. Furthermore, as the efforts for enhancing the work of the cycle, the optimization research is also conducted with numerical calculation. - Highlights: • Modified sequential Carnot cycles are proposed for evaluating low grade heat sources. • Performance of sequential Carnot cycles is calculated analytically. • Optimization study for the cycle is conducted with numerical solver. • Maximum work from a heat source under a certain condition is obtained by equations

  8. Heat capacity and transition behavior of sucrose by standard, fast scanning and temperature-modulated calorimetry

    Energy Technology Data Exchange (ETDEWEB)

    Magoń, A. [Department of Chemistry, University of Technology, 35-959 Rzeszów (Poland); Wurm, A.; Schick, C. [Department of Physics, University of Rostock, 18057 Rostock (Germany); Pangloli, Ph.; Zivanovic, S. [Department of Food Science and Technology, University of Tennessee, Knoxville, TN 37996 (United States); Skotnicki, M. [Department of Pharmaceutical Technology, Poznan University of Medical Sciences, 60-780 Poznań (Poland); Pyda, M., E-mail: mpyda@utk.edu [Department of Chemistry, University of Technology, 35-959 Rzeszów (Poland)

    2014-08-10

    Highlights: • Experimental, apparent heat capacity of sucrose was investigated by advanced thermal analysis. • Vibrational heat capacity of solid state was linked with a low temperature experimental heat capacity of sucrose. • Equilibrium melting parameters of sucrose were determined. • Decomposition, superheating of crystalline sucrose during melting process were presented. • TGA, DSC, TMDSC, and FSC are useful tools for characterization of sucrose. - Abstract: The heat capacity (C{sub p}) of crystalline and amorphous sucrose was determined using standard and quasi-isothermal temperature modulated differential scanning calorimetry. The results were combined with the published data determined by adiabatic calorimetry, and the C{sub p} values are now reported for the wide 5–600 K range. The experimental C{sub p} of solid sucrose at 5–300 K was used to calculate the vibrational, solid C{sub p} based on the vibrational molecular motions. The calculated solid and liquid C{sub p} together with the transition parameters for equilibrium conditions were used as references for detailed quantitative thermal analysis of crystalline and amorphous sucrose. Melting temperature (T{sub m}) of the crystalline sucrose was identified in a broad 442–465 K range with a heat of fusion of 40–46 J/mol determined at heating rates 0.5–20 K/min, respectively. The equilibrium T{sub m} and heat of fusion of crystalline sucrose were estimated at zero heating rate as T{sup o}{sub m} = 424.4 K and ΔH{sup o}{sub f} = 32 kJ/mol, respectively. The glass transition temperature (T{sub g}) of amorphous sucrose was at 331 K with a change in C{sub p} of 267 J/(mol K) as it was estimated from reversing heat capacity by quasi-isothermal TMDSC on cooling. At heating rates less than 30 K/min, thermal decomposition occurred during melting, while at extreme rate of 1000 K/s, degradation was not observed. Data obtained by fast scanning calorimetry (FSC) at 1000 K/s, showed that T{sub m} was

  9. Bimodality and negative heat capacity in multifragmentation

    International Nuclear Information System (INIS)

    Tamain, B.; Bougault, R.; Lopez, O.; Pichon, M.

    2003-01-01

    This contribution addresses the question of the possible link between multifragmentation and the liquid-gas phase transition of nuclear matter. Bi-modality seems to be a robust signal of this link in the sense that theoretical calculations indicate that it is preserved even if a sizeable fraction of the available energy has not been shared among all the degrees of freedom. The corresponding measured properties are coherent with what is expected in a liquid-gas phase transition picture. Moreover, bi-modality and negative heat capacity are observed for the same set of events. (authors)

  10. Prediction of heat capacities and heats of vaporization of organic liquids by group contribution methods

    DEFF Research Database (Denmark)

    Ceriani, Roberta; Gani, Rafiqul; Meirelles, A.J.A.

    2009-01-01

    In the present work a group contribution method is proposed for the estimation of the heat capacity of organic liquids as a function of temperature for fatty compounds found in edible oil and biofuels industries. The data bank used for regression of the group contribution parameters (1395 values...

  11. New experimental heat capacity and enthalpy of formation of lithium cobalt oxide

    International Nuclear Information System (INIS)

    Gotcu-Freis, Petronela; Cupid, Damian M.; Rohde, Magnus; Seifert, Hans J.

    2015-01-01

    Highlights: • LiCoO 2 heat capacity was measured in the temperature range (160 to 953) K using DSC. • Continuous/discontinuous methods were applied on different types of calorimeters. • Enthalpy increment of LiCoO 2 was determined using drop calorimetry at T = 974 K. • Enthalpies of formation were evaluated from oxide melt drop solution calorimetry. - Abstract: The heat capacity of LiCoO 2 (O3-phase), constituent material in cathodes for lithium-ion batteries, was measured using two differential scanning calorimeters over the temperature range from (160 to 953) K (continuous method). As an alternative, the discontinuous method was employed over the temperature range from (493 to 693) K using a third calorimeter. Based on the results obtained, the enthalpy increment of LiCoO 2 was derived from T = 298.15 K up to 974.15 K. Very good agreement was obtained between the derived enthalpy increment and our independent measurements of enthalpy increment using transposed temperature drop calorimetry at 974.15 K. In addition, values of the enthalpy of formation of LiCoO 2 from the constituent oxides and elements were assessed based on measurements of enthalpy of dissolution using high temperature oxide melt drop solution calorimetry. The high temperature values obtained by these measurements are key input data in safety analysis and optimisation of the battery management systems which accounts for possible thermal runaway events

  12. Determination of the thermal conductivity and specific heat capacity of neem seeds by inverse problem method

    Directory of Open Access Journals (Sweden)

    S.N. Nnamchi

    2010-01-01

    Full Text Available Determination of the thermal conductivity and the specific heat capacity of neem seeds (Azadirachta indica A. Juss usingthe inverse method is the main subject of this work. One-dimensional formulation of heat conduction problem in a spherewas used. Finite difference method was adopted for the solution of the heat conduction problem. The thermal conductivityand the specific heat capacity were determined by least square method in conjunction with Levenberg-Marquardt algorithm.The results obtained compare favourably with those obtained experimentally. These results are useful in the analysis ofneem seeds drying and leaching processes.

  13. Heat capacity measurements of sub-nanoliter volumes of liquids using bimaterial microchannel cantilevers

    Science.gov (United States)

    Khan, M. F.; Miriyala, N.; Lee, J.; Hassanpourfard, M.; Kumar, A.; Thundat, T.

    2016-05-01

    Lab-on-a-Chip compatible techniques for thermal characterization of miniaturized volumes of liquid analytes are necessary in applications such as protein blotting, DNA melting, and drug development, where samples are either rare or volume-limited. We developed a closed-chamber calorimeter based on a bimaterial microchannel cantilever (BMC) for sub-nanoliter level thermal analysis. When the liquid-filled BMC is irradiated with infrared (IR) light at a specific wavelength, the IR absorption by the liquid analyte results in localized heat generation and the subsequent deflection of the BMC, due to a thermal expansion mismatch between the constituent materials. The time constant of the deflection, which is dependent upon the heat capacity of the liquid analyte, can be directly measured by recording the time-dependent bending of the BMC. We have used the BMC to quantitatively measure the heat capacity of five volatile organic compounds. With a deflection noise level of ˜10 nm and a signal-to-noise ratio of 68:1, the BMC offers a sensitivity of 30.5 ms/(J g-1 K-1) and a resolution of 23 mJ/(g K) for ˜150 pl liquid for heat capacity measurements. This technique can be used for small-scale thermal characterization of different chemical and biological samples.

  14. Debye temperature, thermal expansion, and heat capacity of TcC up to 100 GPa

    Energy Technology Data Exchange (ETDEWEB)

    Song, T., E-mail: songting@mail.lzjtu.cn [School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070 (China); School of Material Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China); Ma, Q. [School of Material Science and Engineering, Lanzhou University of Technology, Lanzhou 730050 (China); Tian, J.H. [School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070 (China); Liu, X.B. [School of Physics and Information Science, Tianshui Normal University, Tianshui 741000 (China); Ouyang, Y.H.; Zhang, C.L.; Su, W.F. [School of Mathematics and Physics, Lanzhou Jiaotong University, Lanzhou 730070 (China)

    2015-01-15

    Highlights: • A number of thermodynamic properties of rocksalt TcC are investigated for the first time. • The quasi-harmonic Debye model is applied to take into account the thermal effect. • The pressure and temperature up to about 100 GPa and 3000 K, respectively. - Abstract: Debye temperature, thermal expansion coefficient, and heat capacity of ideal stoichiometric TcC in the rocksalt structure have been studied systematically by using ab initio plane-wave pseudopotential density functional theory method within the generalized gradient approximation. Through the quasi-harmonic Debye model, in which the phononic effects are considered, the dependences of Debye temperature, thermal expansion coefficient, constant-volume heat capacity, and constant-pressure heat capacity on pressure and temperature are successfully predicted. All the thermodynamic properties of TcC with rocksalt phase have been predicted in the entire temperature range from 300 to 3000 K and pressure up to 100 GPa.

  15. Magnetic-susceptibility and heat-capacity measurements on PrRhSb

    International Nuclear Information System (INIS)

    Malik, S.K.; Takeya, H.; Gschneidner, K.A. Jr.

    1994-01-01

    Magnetic-susceptibility (ac and dc) and heat-capacity measurements have been carried out on the compound PrRhSb. These measurements reveal two magnetic transitions in this compound---one at about 18 K and the other around 6 K. In the dc susceptibility the 18-K transition is evident as the temperature below which a magnetic correlation sets in and the susceptibility is found to be field dependent. The lower transition manifests as a peak in the susceptibility of zero-field-cooled samples which were measured in low applied fields. The electronic-specific-heat coefficient, γ, is found to be 33 mJ/mol K 2 between 40 and 70 K after correcting for the lattice contribution taken to be the same as in its La analog. The γ value is fairly large for a Pr compound and may be indicative of moderately heavy quasiparticles. A Kondo-type interaction of the Pr 4f electrons with the conduction electrons may be responsible for high-magnetic-ordering temperatures and the moderately large γ value in this compound

  16. Low-temperature heat capacity of Al(C11H19O2)3

    International Nuclear Information System (INIS)

    Bespyatov, Michael A.; Chernyaikin, Ivan S.; Naumov, Viktor N.; Stabnikov, Pavel A.; Gelfond, Nikolay V.

    2014-01-01

    Highlights: • The temperature dependence of heat capacity of Al(C 11 H 19 O 2 ) 3 has been measured. • The experimental data were used to calculate standard thermodynamic functions. • The thermodynamic functions at 298.15 K are presented. - Abstract: The heat capacity of Al(C 11 H 19 O 2 ) 3 was measured by adiabatic-shield calorimetry in the temperature range 6–320 K; no transition or thermal anomalies were found. The thermodynamic functions (entropy, enthalpy, and reduced Gibbs free energy) at 298.15 K have been calculated using the obtained experimental heat capacity data. The obtained standard values are as follows: C° p,m = (882.3 ± 1.3) J mol −1 K −1 , Δ 0 298.15 S° m = J(980 ± 2) mol −1 K −1 , Δ 0 298.15 H° m = (145.1 ± 0.2) kJ mol −1 , Φ° m = (493.4 ± 1.7) J mol −1 K −1

  17. Evaluating Moisture Control of Variable-Capacity Heat Pumps in Mechanically Ventilated, Low-Load Homes in Climate Zone 2A

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Eric [Univ. of Central Florida, Orlando, FL (United States). Florida Solar Energy Center; Withers, Chuck [Univ. of Central Florida, Orlando, FL (United States). Florida Solar Energy Center; McIlvaine, Janet [Univ. of Central Florida, Orlando, FL (United States). Florida Solar Energy Center; Chasar, Dave [Univ. of Central Florida, Orlando, FL (United States). Florida Solar Energy Center; Beal, David [Univ. of Central Florida, Orlando, FL (United States). Florida Solar Energy Center

    2018-02-07

    The well-sealed, highly insulated building enclosures constructed by today's home building industry coupled with efficient lighting and appliances are achieving significantly reduced heating and cooling loads. These low-load homes can present a challenge when selecting appropriate space-conditioning equipment. Conventional, fixed-capacity heating and cooling equipment is often oversized for small homes, causing increased first costs and operating costs. Even if fixed-capacity equipment can be properly specified for peak loads, it remains oversized for use during much of the year. During these part-load cooling hours, oversized equipment meets the target dry-bulb temperatures very quickly, often without sufficient opportunity for moisture control. The problem becomes more acute for high-performance houses in humid climates when meeting ASHRAE Standard 62.2 recommendations for wholehouse mechanical ventilation.

  18. Zeolite Y Adsorbents with High Vapor Uptake Capacity and Robust Cycling Stability for Potential Applications in Advanced Adsorption Heat Pumps.

    Science.gov (United States)

    Li, Xiansen; Narayanan, Shankar; Michaelis, Vladimir K; Ong, Ta-Chung; Keeler, Eric G; Kim, Hyunho; McKay, Ian S; Griffin, Robert G; Wang, Evelyn N

    2015-01-01

    Modular and compact adsorption heat pumps (AHPs) promise an energy-efficient alternative to conventional vapor compression based heating, ventilation and air conditioning systems. A key element in the advancement of AHPs is the development of adsorbents with high uptake capacity, fast intracrystalline diffusivity and durable hydrothermal stability. Herein, the ion exchange of NaY zeolites with ingoing Mg 2+ ions is systematically studied to maximize the ion exchange degree (IED) for improved sorption performance. It is found that beyond an ion exchange threshold of 64.1%, deeper ion exchange does not benefit water uptake capacity or characteristic adsorption energy, but does enhance the vapor diffusivity. In addition to using water as an adsorbate, the uptake properties of Mg,Na-Y zeolites were investigated using 20 wt.% MeOH aqueous solution as a novel anti-freeze adsorbate, revealing that the MeOH additive has an insignificant influence on the overall sorption performance. We also demonstrated that the labscale synthetic scalability is robust, and that the tailored zeolites scarcely suffer from hydrothermal stability even after successive 108-fold adsorption/desorption cycles. The samples were analyzed using N 2 sorption, 27 Al/ 29 Si MAS NMR spectroscopy, ICP-AES, dynamic vapor sorption, SEM, Fick's 2 nd law and D-R equation regressions. Among these, close examination of sorption isotherms for H 2 O and N 2 adsorbates allows us to decouple and extract some insightful information underlying the complex water uptake phenomena. This work shows the promising performance of our modified zeolites that can be integrated into various AHP designs for buildings, electronics, and transportation applications.

  19. Simultaneous measurement of thermal conductivity and heat capacity of bulk and thin film materials using frequency-dependent transient thermoreflectance method.

    Science.gov (United States)

    Liu, Jun; Zhu, Jie; Tian, Miao; Gu, Xiaokun; Schmidt, Aaron; Yang, Ronggui

    2013-03-01

    The increasing interest in the extraordinary thermal properties of nanostructures has led to the development of various measurement techniques. Transient thermoreflectance method has emerged as a reliable measurement technique for thermal conductivity of thin films. In this method, the determination of thermal conductivity usually relies much on the accuracy of heat capacity input. For new nanoscale materials with unknown or less-understood thermal properties, it is either questionable to assume bulk heat capacity for nanostructures or difficult to obtain the bulk form of those materials for a conventional heat capacity measurement. In this paper, we describe a technique for simultaneous measurement of thermal conductivity κ and volumetric heat capacity C of both bulk and thin film materials using frequency-dependent time-domain thermoreflectance (TDTR) signals. The heat transfer model is analyzed first to find how different combinations of κ and C determine the frequency-dependent TDTR signals. Simultaneous measurement of thermal conductivity and volumetric heat capacity is then demonstrated with bulk Si and thin film SiO2 samples using frequency-dependent TDTR measurement. This method is further testified by measuring both thermal conductivity and volumetric heat capacity of novel hybrid organic-inorganic thin films fabricated using the atomic∕molecular layer deposition. Simultaneous measurement of thermal conductivity and heat capacity can significantly shorten the development∕discovery cycle of novel materials.

  20. Voluntary Running Aids to Maintain High Body Temperature in Rats Bred for High Aerobic Capacity

    Science.gov (United States)

    Karvinen, Sira M.; Silvennoinen, Mika; Ma, Hongqiang; Törmäkangas, Timo; Rantalainen, Timo; Rinnankoski-Tuikka, Rita; Lensu, Sanna; Koch, Lauren G.; Britton, Steven L.; Kainulainen, Heikki

    2016-01-01

    The production of heat, i.e., thermogenesis, is a significant component of the metabolic rate, which in turn affects weight gain and health. Thermogenesis is linked to physical activity (PA) level. However, it is not known whether intrinsic exercise capacity, aging, and long-term voluntary running affect core body temperature. Here we use rat models selectively bred to differ in maximal treadmill endurance running capacity (Low capacity runners, LCR and High capacity Runners, HCR), that as adults are divergent for aerobic exercise capacity, aging, and metabolic disease risk to study the connection between PA and body temperature. Ten high capacity runner (HCR) and ten low capacity runner (LCR) female rats were studied between 9 and 21 months of age. Rectal body temperature of HCR and LCR rats was measured before and after 1-year voluntary running/control intervention to explore the effects of aging and PA. Also, we determined whether injected glucose and spontaneous activity affect the body temperature differently between LCR and HCR rats at 9 vs. 21 months of age. HCRs had on average 1.3°C higher body temperature than LCRs (p temperature level of HCRs to similar levels with LCRs. The opportunity to run voluntarily had a significant impact on the body temperature of HCRs (p temperature at a similar level as when at younger age. Compared to LCRs, HCRs were spontaneously more active, had higher relative gastrocnemius muscle mass and higher UCP2, PGC-1α, cyt c, and OXPHOS levels in the skeletal muscle (p temperature of LCRs. However, glucose injection resulted in a lowering of the body temperature of LCRs (p temperature compared to rats born with low exercise capacity and disease risk. Voluntary running allowed HCRs to maintain high body temperature during aging, which suggests that high PA level was crucial in maintaining the high body temperature of HCRs. PMID:27504097

  1. Laboratory Development of A High Capacity Gas-Fired paper Dryer

    Energy Technology Data Exchange (ETDEWEB)

    Chudnovsky, Yaroslav [Gas Technology Institute, Des Plaines, IL (United States); Kozlov, Aleksandr [Gas Technology Institute, Des Plaines, IL (United States); Sherrow, Lester [Gas Technology Institute, Des Plaines, IL (United States)

    2005-09-30

    Paper drying is the most energy-intensive and temperature-critical aspect of papermaking. It is estimated that about 67% of the total energy required in papermaking is used to dry paper. The conventional drying method uses a series of steam-heated metal cylinders that are required to meet ASME codes for pressure vessels, which limits the steam pressure to about 160 psig. Consequently, the shell temperature and the drying capacity are also limited. Gas Technology Institute together with Boise Paper Solutions, Groupe Laparrier and Verreault (GL&V) USA Inc., Flynn Burner Corporation and with funding support from the U.S. Department of Energy, U.S. natural gas industry, and Gas Research Institute is developing a high efficiency gas-fired paper dryer based on a combination of a ribbon burner and advanced heat transfer enhancement technique. The Gas-Fired Paper Dryer (GFPD) is a high-efficiency alternative to conventional steam-heated drying drums that typically operate at surface temperatures in the 300ºF range. The new approach was evaluated in laboratory and pilot-scale testing at the Western Michigan University Paper Pilot Plant. Drum surface temperatures of more than 400ºF were reached with linerboard (basis weight 126 lb/3000 ft2) production and resulted in a 4-5 times increase in drying rate over a conventional steam-heated drying drum. Successful GFPD development and commercialization will provide large energy savings to the paper industry and increase paper production rates from dryer-limited (space- or steam-limited) paper machines by an estimated 10 to 20%, resulting in significant capital costs savings for both retrofits and new capacity.

  2. Heat capacity of 1-pentylamine and 1-hexylamine: Experimental determination and modeling through a two-state association model (TSAM)

    International Nuclear Information System (INIS)

    Navia, P.; Bessières, D.; Plantier, F.

    2013-01-01

    Highlights: ► Experimental determination of heat capacity of two primary amines, over wide ranges of pressure and temperature. ► Comprehensive description of the association effect between amines molecules. ► Thermodynamics of complex fluids. ► Statistical thermodynamic approach. - Abstract: We report new experimental data of heat capacity of two primary amines, namely 1-pentylamine and 1-hexylamine over wide ranges of pressure [0.1–60 (MPa)] and temperature [303.15–403.15 (K)]. The experimental behaviour of the heat capacity versus temperature and pressure is analyzed. An attempt to rationalize this behaviour is performed through a two-state association model (TSAM), which allows expressing the specific effect due to association at molecular level. It appears that the heat capacity trend versus temperature is clearly governed by auto-association between amines molecules. The physical meaningful of the (TSAM) model parameters highlights the capability of this approach to capture the heat capacity behavior of the amines.

  3. The influence of working memory capacity on experimental heat pain.

    Science.gov (United States)

    Nakae, Aya; Endo, Kaori; Adachi, Tomonori; Ikeda, Takashi; Hagihira, Satoshi; Mashimo, Takashi; Osaka, Mariko

    2013-10-01

    Pain processing and attention have a bidirectional interaction that depends upon one's relative ability to use limited-capacity resources. However, correlations between the size of limited-capacity resources and pain have not been evaluated. Working memory capacity, which is a cognitive resource, can be measured using the reading span task (RST). In this study, we hypothesized that an individual's potential working memory capacity and subjective pain intensity are related. To test this hypothesis, we evaluated 31 healthy participants' potential working memory capacity using the RST, and then applied continuous experimental heat stimulation using the listening span test (LST), which is a modified version of the RST. Subjective pain intensities were significantly lower during the challenging parts of the RST. The pain intensity under conditions where memorizing tasks were performed was compared with that under the control condition, and it showed a correlation with potential working memory capacity. These results indicate that working memory capacity reflects the ability to process information, including precise evaluations of changes in pain perception. In this work, we present data suggesting that changes in subjective pain intensity are related, depending upon individual potential working memory capacities. Individual working memory capacity may be a phenotype that reflects sensitivity to changes in pain perception. Copyright © 2013 American Pain Society. Published by Elsevier Inc. All rights reserved.

  4. Analysis of the Storage Capacity in an Aggregated Heat Pump Portfolio

    DEFF Research Database (Denmark)

    Nielsen, Kirsten Mølgaard; Andersen, Palle; Pedersen, Tom Søndergård

    2015-01-01

    Energy storages connected to the power grid will be of great importance in the near future. A pilot project has investigated more than 100 single family houses with heat pumps all connected to the internet. The houses have large heat capacities and it is possible to move energy consumption to sui...... (scheduling) algorithm. The properties of this scheduling are investigated in the paper especially the flexibility and ability to trade on the intra-day regulating market is in focus....

  5. Advanced Analysis of Isobaric Heat Capacities by Mathematical Gnostics

    Czech Academy of Sciences Publication Activity Database

    Wagner, Zdeněk; Bendová, Magdalena; Rotrekl, Jan; Velíšek, Petr; Storch, Jan; Uchytil, Petr; Setničková, Kateřina; Řezníčková Čermáková, Jiřina

    2017-01-01

    Roč. 46, 9-10 (2017), s. 1836-1853 ISSN 0095-9782. [International Symposium on Solubility Phenomena and Related Equilibrium Processes. Geneva, 24.07.2016-29.07.2016] R&D Projects: GA MŠk LD14090 Institutional support: RVO:67985858 Keywords : isobaric heat capacity * ionic liquids * mathematical gnostics Subject RIV: CF - Physical ; Theoretical Chemistry OBOR OECD: Physical chemistry Impact factor: 1.342, year: 2016

  6. Heat capacity measurements of sub-nanoliter volumes of liquids using bimaterial microchannel cantilevers

    International Nuclear Information System (INIS)

    Khan, M. F.; Miriyala, N.; Hassanpourfard, M.; Thundat, T.; Lee, J.; Kumar, A.

    2016-01-01

    Lab-on-a-Chip compatible techniques for thermal characterization of miniaturized volumes of liquid analytes are necessary in applications such as protein blotting, DNA melting, and drug development, where samples are either rare or volume-limited. We developed a closed-chamber calorimeter based on a bimaterial microchannel cantilever (BMC) for sub-nanoliter level thermal analysis. When the liquid-filled BMC is irradiated with infrared (IR) light at a specific wavelength, the IR absorption by the liquid analyte results in localized heat generation and the subsequent deflection of the BMC, due to a thermal expansion mismatch between the constituent materials. The time constant of the deflection, which is dependent upon the heat capacity of the liquid analyte, can be directly measured by recording the time-dependent bending of the BMC. We have used the BMC to quantitatively measure the heat capacity of five volatile organic compounds. With a deflection noise level of ∼10 nm and a signal-to-noise ratio of 68:1, the BMC offers a sensitivity of 30.5 ms/(J g"−"1" K"−"1) and a resolution of 23 mJ/(g K) for ∼150 pl liquid for heat capacity measurements. This technique can be used for small-scale thermal characterization of different chemical and biological samples.

  7. Experimental Study on Compression/Absorption High-Temperature Hybrid Heat Pump with Natural Refrigerant Mixture

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Ji Young; Park, Seong Ryong; Baik, Young Jin; Chang, Ki Chang; Ra, Ho Sang; Kim, Min Sung [Korea Institute of Energy Research, Daejeon (Korea, Republic of); Kim, Yong Chan [Korea University, Seoul (Korea, Republic of)

    2011-12-15

    This research concerns the development of a compression/absorption high-temperature hybrid heat pump that uses a natural refrigerant mixture. Heat pumps based on the compression/absorption cycle offer various advantages over conventional heat pumps based on the vapor compression cycle, such as large temperature glide, temperature lift, flexible operating range, and capacity control. In this study, a lab-scale prototype hybrid heat pump was constructed with a two-stage compressor, absorber, desorber, desuperheater, solution heat exchanger, solution pump, liquid/vapor separator, and rectifier as the main components. The hybrid heat pump system operated at 10-kW-class heating capacity producing hot water whose temperature was more than 90 .deg. C when the heat source and sink temperatures were 50 .deg. C. Experiments with various NH{sub 3}/H{sub 2}O mass fractions and compressor/pump circulation ratios were performed on the system. From the study, the system performance was optimized at a specific NH{sub 3} concentration.

  8. Surfaces for high heat dissipation with no Leidenfrost limit

    Science.gov (United States)

    Sajadi, Seyed Mohammad; Irajizad, Peyman; Kashyap, Varun; Farokhnia, Nazanin; Ghasemi, Hadi

    2017-07-01

    Heat dissipation from hot surfaces through cooling droplets is limited by the Leidenfrost point (LFP), in which an insulating vapor film prevents direct contact between the cooling droplet and the hot surface. A range of approaches have been developed to raise this limit to higher temperatures, but the limit still exists. Recently, a surface architecture, decoupled hierarchical structure, was developed that allows the suppression of LFP completely. However, heat dissipation by the structure in the low superheat region was inferior to other surfaces and the structure required an extensive micro/nano fabrication procedure. Here, we present a metallic surface structure with no LFP and high heat dissipation capacity in all temperature ranges. The surface features the nucleate boiling phenomenon independent of the temperature with an approximate heat transfer coefficient of 20 kW m-2 K-1. This surface is developed in a one-step process with no micro/nano fabrication. We envision that this metallic surface provides a unique platform for high heat dissipation in power generation, photonics/electronics, and aviation systems.

  9. Quadrupolar interactions in non-cubic crystal and related extra heat capacities. Possible effects on a sapphire bolometer

    Energy Technology Data Exchange (ETDEWEB)

    Bassou, M. [Tunis Univ. (Tunisia)]|[CEA/DSM/DRECAM/SPEC, Gif-wur-Yvette (France); Rotter, M. [Karlova Univ., Prague (Czech Republic)]|[CEA/DSM/DRECAM/SPEC, Gif-wur-Yvette (France); Bernier, M. [CEA/DSM/DRECAM/SPEC, Gif-wur-Yvette (France); Chapellier, M. [CEA/DSM/DRECAM/SPEC, Gif-wur-Yvette (France)

    1996-02-11

    It is shown that in a non-cubic crystal, the extra heat capacity due to quadrupolar interaction of nuclear spins >1/2 could be much bigger than the phonon heat capacity when the temperature decreases. The possible coupling between quadrupolar and phonon heat reservoir via paramagnetic impurities is stressed. A NMR experiment done on sapphire is presented with an evaluation of the coupling between the two reservoirs and its consequence on the performance of the bolometer. (orig.).

  10. Quadrupolar interactions in non-cubic crystal and related extra heat capacities. Possible effects on a sapphire bolometer

    International Nuclear Information System (INIS)

    Bassou, M.; Rotter, M.; Bernier, M.; Chapellier, M.

    1996-01-01

    It is shown that in a non-cubic crystal, the extra heat capacity due to quadrupolar interaction of nuclear spins >1/2 could be much bigger than the phonon heat capacity when the temperature decreases. The possible coupling between quadrupolar and phonon heat reservoir via paramagnetic impurities is stressed. A NMR experiment done on sapphire is presented with an evaluation of the coupling between the two reservoirs and its consequence on the performance of the bolometer. (orig.)

  11. Measurement of the molar heat capacities of MoO2 and MoO3 from 350 to 950 K

    International Nuclear Information System (INIS)

    Inaba, H.; Miyahara, K.; Naito, K.

    1984-01-01

    Molar heat capacities of MoO 2 and MoO 3 were measured in the range between 350 and 950 K by means of adiabatic scanning calorimetry. For MoO 2 , a sharp heat-capacity anomaly with a molar enthalpy change of (178 +- 24) J.mol -1 and a molar entropy change of (0.207 +- 0.028) J.K -1 .mol -1 was observed at 865 K, which had not been detected by drop calorimetry. For MoO 3 , two heat-capacity anomalies with molar enthalpy changes of (88 +- 21) and (60 +- 36) J.mol -1 were found at 808 K and 857 K, respectively; neither anomaly had been detected by the drop method. The lattice molar heat capacities of MoO 2 and MoO 3 are estimated as Csub(l,m)(MoO 2 ) = D(469 K/T) + E(578 K/T) + E(876 K/T) and Csub(l,m)(MoO 3 ) = D(208 K/T) + 2E(488 K/T) + E(1170 K/T), where D(x) and E(x) are the Debye and Einstein functions, respectively. The temperature coefficient of the electronic molar heat capacity of MoO 2 is estimated as (6.0 +- 0.5) mJ.K -2 .mol -1 . The excess heat capacity in MoO 3 found at higher temperatures is interpreted as being due to vacancy formation with a molar activation energy of (98 +-5) kJ.mol -1 . The origin of the heat-capacity anomalies is inferred as arising from the slight movement of distorted MoO 6 octahedra in the MoO 2 and MoO 3 structures. (author)

  12. Device for determining heat capacity of gases and gas mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Nachev, N

    1980-01-01

    This article describes the use of a capillary-flow colorimeter to determine the heat capacity of gases and gaseous mixtures. The research and tests confirm the possibility and advisability of making these measurements. The calorimeters are graduated to allow for the influence of the pressure and temperature of the investigated gas and exchange with the environment.

  13. The Effect of Moisture Content and Temperature on the Specific Heat Capacity of Nut and Kernel of Two Iranian Pistachio Varieties

    Directory of Open Access Journals (Sweden)

    A.R Salari Kia

    2014-04-01

    Full Text Available Pistachio has a special ranking among Iranian agricultural products. Iran is known as the largest producer and exporter of pistachio in the world. Agricultural products are imposed under different thermal treatments during storage and processing. Designing all these processes requires thermal parameters of the products such as specific heat capacity. Regarding the importance of pistachio processing as an exportable product, in this study the specific heat capacity of nut and kernel of two varieties of Iranian pistachio (Kalle-Ghochi and Badami were investigated at four levels of moisture content (initial moisture content (5%, 15%, 25% and 40% w.b. and three levels of temperature (40, 50 and 60°C. In both varieties, the differences between the data were significant at the 1% of probability; however, the effect of moisture content was greater than that of temperature. The results indicated that the specific heat capacity of both nuts and kernels increase logarithmically with increase of moisture content and also increase linearly with increase of temperature. This parameter has altered for nut and kernel of Kalle-Ghochi and Badami varieties within the range of 1.039-2.936 kJ kg-1 K-1, 1.236-3.320 kJ kg-1 K-1, 0.887-2.773 kJ kg-1 K-1 and 0.811-2.914 kJ kg-1 K-1, respectively. Moreover, for any given level of temperature, the specific heat capacity of kernels was higher than that of nuts. Finally, regression models with high R2 values were developed to predict the specific heat capacity of pistachio varieties as a function of moisture content and temperature

  14. Heat capacities and phase analysis of the superconductive compounds Mosub(6+y0) Se8 and Gdsub(x0) Mosub(6+y0) Se8

    International Nuclear Information System (INIS)

    Nerz, K.P.

    1979-02-01

    High precision heat capacity measurements were performed on a high quality sample of Mo 6 Se 8 . The values obtained for the Sommerfeld-constant γ, density of states N(Esub(F)) and entropy S 2 (Tsub(c)) of the electronic system are a factor 1.5 to 2 larger than have been published earlier by other groups. The differences are attributed to the lower concentration of impurity phases in our sample. Our sample of Mo 6 Se 8 shows a discontinuity in the electronic heat capacity at Tsub(c) with a relative height (Csub(es)-Csub(en))/Csub(en) which is a factor 1.6 larger compared to an ideal BCS-superconductor. The energy gap in the excitation spectrum of the superconductor Mo 6 Se 8 is a factor 1.4 wider than for an ideal BCS-superconductor in the observed temperature regime. Our data for the electronic heat capacity of the superconducting phase Mo 6 Se 8 are in good agreement with the calculated values corresponding to the 'strong coupling'-model of Padamsee et al. For the characteristic quantity of the electron-phonon interaction, lambda, a value of 0.8 was calculated. All these results support the conclusions that Mo 6 Se 8 behaves like a superconductor with a strong electron-phonon interaction. In addition heat capacity measurements have been made for samples of the ternary Chevrel-phase compounds 'Gdsub(x 0 )Mosub(6+y 0 )Se 8 ' which were prepared by a variety of methods. A quantitative analysis of impurity phases has been made from the heat capacity data. (orig.) [de

  15. A new experimental method to determine specific heat capacity of inhomogeneous concrete material with incorporated microencapsulated-PCM

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2014-01-01

    PCM. This paper describes the development of the new material and the experimental set-up to determine the specific heat capacity of the PCM concrete material. Moreover, various methods are proposed and compared to calculate the specific heat capacity of the PCM concrete. Finally, it is hoped......The study presented in this paper focuses on an experimental investigation of the specific heat capacity as a function of the temperature Cp (T) of concrete mixed with various amounts of phase change material (PCM). The tested specimens are prepared by directly mixing concrete and microencapsulated...... that this work can be used as an inspiration and guidance to perform measurements on the various composite materials containing PCM....

  16. Investigation of the variation of the specific heat capacity of local soil samples from the Niger delta, Nigeria with moisture content

    International Nuclear Information System (INIS)

    Ofoegbu, C.O.; Adjepong, S.K.

    1987-11-01

    Results of an investigation of the variation, with moisture content, of the specific heat capacity of samples of three texturally different types of soil (clayey, sandy and sandy loam) obtained from the Niger delta area of Nigeria, are presented. The results show that the specific heat capacities of the soils studied, increase with moisture content. This increase is found to be linear for the entire range of moisture contents considered (0-25%), in the case of the sandy loam soil while for the clayey and sandy soils the specific heat capacity is found to increase linearly with moisture content up to about 15% after which the increase becomes parabolic. The rate of increase of specific heat capacity with moisture content appears to be highest in the clayey soil and lowest in the sandy soil. It is thought that the differences in the rates of increase of specific heat capacity with moisture content, observed for the soils, reflect the soils' water-retention capacities. (author) 3 refs, 5 figs

  17. Heat-capacity behaviour of Ce{sub 2}Pd{sub 2}In

    Energy Technology Data Exchange (ETDEWEB)

    Mallik, R; Sampathkumaran, E V [Tata Institute of Fundamental Research, Mumbai (India)

    1997-12-31

    We report here the magnetic behaviour of Ce{sub 2}Pd{sub 2}In by heat capacity (C) and magnetization studies and propose that this compound exhibits two magnetic transitions, T{sub N}=4.5K and T{sub C}=3.6K. 3 refs., 1 fig.

  18. Negative heat capacity at phase-separation in macroscopic systems

    OpenAIRE

    Gross, D. H. E.

    2005-01-01

    Systems with long-range as well with short-range interactions should necessarily have a convex entropy S(E) at proper phase transitions of first order, i.e. when a separation of phases occurs. Here the microcanonical heat capacity c(E)= -\\frac{(\\partial S/\\partial E)^2}{\\partial^2S/\\partial E^2} is negative. This should be observable even in macroscopic systems when energy fluctuations with the surrounding world can be sufficiently suppressed.

  19. Complex Heat Capacity of Lithium Borate Glasses Studied by Modulated DSC

    International Nuclear Information System (INIS)

    Matsuda, Yu; Ike, Yuji; Matsui, Chihiro; Kodama, Masao; Kojima, Seiji

    2006-01-01

    Complex heat capacity, C p * = C p ' - iC p '', of lithium borate glasses Li2O·(1-x)B2O3 (x = 0.00 - 0.33) has been investigated by Modulated DSC (MDSC). We have successfully observed the frequency dependent C p * by MDSC in the frequency range 0.01 to 0.1 Hz, and the average relaxation time of glass transition has been determined as a function of temperature. Moreover, the composition dependence of the thermal properties has been investigated. The calorimetric glass transition temperatures become higher with the increase of concentration of Li2O and show the board maximum around x = 0.26-0.28. The width of glass transition region becomes narrower as Li2O increases. These results relate to the change of the fragility of the system. It has been proven that the complex heat capacity spectroscopy by MDSC is a powerful tool to investigate the glass transition phenomena

  20. Complex Heat Capacity of Lithium Borate Glasses Studied by Modulated DSC

    Science.gov (United States)

    Matsuda, Yu; Matsui, Chihiro; Ike, Yuji; Kodama, Masao; Kojima, Seiji

    2006-05-01

    Complex heat capacity, Cp* = Cp' - iCp″, of lithium borate glasses Li2Oṡ(1-x)B2O3 (x = 0.00 - 0.33) has been investigated by Modulated DSC (MDSC). We have successfully observed the frequency dependent Cp* by MDSC in the frequency range 0.01 to 0.1 Hz, and the average relaxation time of glass transition has been determined as a function of temperature. Moreover, the composition dependence of the thermal properties has been investigated. The calorimetric glass transition temperatures become higher with the increase of concentration of Li2O and show the board maximum around x = 0.26-0.28. The width of glass transition region becomes narrower as Li2O increases. These results relate to the change of the fragility of the system. It has been proven that the complex heat capacity spectroscopy by MDSC is a powerful tool to investigate the glass transition phenomena.

  1. 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

  2. Energy density and storage capacity cost comparison of conceptual solid and liquid sorption seasonal heat storage systems for low-temperature space heating

    NARCIS (Netherlands)

    Scapino, L.; Zondag, H.A.; Van Bael, J.; Diriken, J.; Rindt, C.C.M.

    Sorption heat storage can potentially store thermal energy for long time periods with a higher energy density compared to conventional storage technologies. A performance comparison in terms of energy density and storage capacity costs of different sorption system concepts used for seasonal heat

  3. 1990s: High Capacity Backbones

    Indian Academy of Sciences (India)

    First page Back Continue Last page Overview Graphics. 1990s: High Capacity Backbones. Backbone capacities increased from 2.5 Gb/s to 100s of Gb/s during the 1990's. Wavelength division multiplexing with 160 waves of 10 Gb/s was commercially available. Several high-capacity backbones built in the US and Europe.

  4. Experimental heat capacity of solid hydrogen as a function of molar volume

    International Nuclear Information System (INIS)

    Krause, J.K.

    1978-01-01

    Constant volume heat capacity measurements have been made on six solid hydrogen samples with low orthohydrogen concentrations. The measurements extend from approximately 1.5 K to the melting line, with molar volumes ranging from 22.787 cm 3 /mole to 16.193 cm 3 /mole. Although clustering of the ortho molecules was observed, the low temperature heat capacity anomaly due to the orthohydrogen pairs could be described quite well by the assumption of a fixed distribution. The data were corrected to obtain a lattice heat capacity which on extrapolation to T = 0 yielded Debye temperatures and a volume dependent Grueneisen parameter. A modified Mie-Grueneisen approximation was used to define a volume and temperature dependent Grueneisen parameter which was used to calculate the equation of state, P(V,T), and isothermal bulk modulus, B/sub T/(V,T), for the six isochores. An extrapolation of the equation of state to T = 0 and P = 0 by two different methods yields a molar volume which, when compared with other determinations, gives a recommended value of 23.20 +- 0.05 cm 3 /mole. A rapid increase in the conversion rate of orthohydrogen to parahydrogen was observed at approximately theta/sub o/12. The molar volumes along the melting curve also have been determined directly for the first time in this volume range. These results have been used to show that a low temperature Lindemann melting relation is only approximately valid for solid hydrogen to 50 K

  5. Power Output Stability Research for Harvesting Automobile Exhaust Energy with Heat Capacity Material as Intermediate Medium

    Science.gov (United States)

    Xiao, Longjie; He, Tianming; Mei, Binyu; Wang, Yiping; Wang, Zongsong; Tan, Gangfeng

    2018-06-01

    Automobile exhaust energy thermoelectric utilization can promote energy-saving and emission-reduction. Unexpected urban traffic conditions lead to the hot-end temperature instability of the exhaust pipe-mounted thermoelectric generator (TEG), and influence the TEG power generation efficiency. The heat conduction oil circulation located at the hot-end could smooth the temperature fluctuation, at the expense of larger system size and additional energy supply. This research improves the TEG hot-end temperature stability by installing solid heat capacity material (SHCM) to the area between the outer wall of the exhaust pipe and the TEG, which has the merits of simple structure, light weight and no additional energy consumption. The exhaust temperature and flow rate characteristics with various driving conditions are firstly studied for the target engine. Then the convective heat transfer models of SHCM's hot-end and thermoelectric material's cold-end are established. Meanwhile, SHCM thermal properties' effects on the amplitude and response speed of the TEG hot-end temperature are studied. The candidate SHCM with the characteristics of low thermal resistance and high heat capacity is determined. And the heat transfer model going through from TEG's hot-end to the cold-end is established. The results show that the SHCM significantly improves the TEG hot-end temperature stability but slightly reduces the average power output. When the engine working conditions change a lot, the SHCM's improvement on the TEG hot-end temperature stability is more significant, but the reduction of the average power output becomes more remarkable.

  6. Heat capacity and Joule-Thomson coefficient of selected n-alkanes at 0.1 and 10 MPa in broad temperature ranges

    DEFF Research Database (Denmark)

    Regueira Muñiz, Teresa; Varzandeh, Farhad; Stenby, Erling Halfdan

    2017-01-01

    Isobaric heat capacity of six n-alkanes, i.e. n-hexane, n-octane, n-decane, n-dodecane, n-tetradecane and n-hexadecane, was determined with a Calvet type differential heat-flux calorimeter at 0.1 and 10 MPa in a broad temperature range. The measured isobaric heat capacity data were combined...

  7. Heat capacity jumps induced by magnetic field in the Er{sub 2}HoAl{sub 5}O{sub 12} garnet

    Energy Technology Data Exchange (ETDEWEB)

    Shevchenko, E.V. [Centre for Diagnostics of Functional Materials for Medicine, Pharmacology and Nanoelectronics, St. Petersburg State University, St. Petersburg, 198504 (Russian Federation); Charnaya, E.V., E-mail: charnaya@live.com [Physics Department, St. Petersburg State University, St. Petersburg, 198504 (Russian Federation); Lee, M.K. [Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan (China); NSC Instrument Center at NCKU, Tainan, 70101 Taiwan (China); Chang, L.J. [Department of Physics, National Cheng Kung University, Tainan, 70101 Taiwan (China); Khazanov, E.N.; Taranov, A.V. [Kotel' nikov Institute of Radio Engineering and Electronics RAS, 125009 (Russian Federation); Bugaev, A.S. [Moscow Institute of Physics and Technology, Moscow, 141700 (Russian Federation)

    2017-01-30

    Measurements of the heat capacity were carried out for the mixed Er{sub 2}HoAl{sub 5}O{sub 12} garnet at magnetic fields up to 15 T. The heat capacity variations at low temperatures were dominated by the Schottky anomalies. In addition, anomalous sharp steps in the heat capacity were observed in magnetic fields stronger than 8 T upon cooling as well as upon warming. The temperatures of the steps increased with increasing magnetic field. Jumps found upon cooling and warming were shifted relative to each other showing the thermal hysteresis. The sharp decrease in the heat capacity at low temperatures suggested the blocking of magnetic flips induced by strong enough magnetic fields. - Highlights: • Anomalous steps of the heat capacity were observed in the Er{sub 2}HoAl{sub 5}O{sub 12} garnet. • The steps are induced by magnetic field at low temperatures. • The temperatures of the steps increased with increasing magnetic field. • The steps show a pronounced thermal hysteresis. • The findings suggest the blocking of the magnetic moment flips at field.

  8. Thermodynamic investigation of several natural polyols (I): Heat capacities and thermodynamic properties of xylitol

    Energy Technology Data Exchange (ETDEWEB)

    Tong Bo [Thermochemistry Laboratory, Dalian Institute of Chemical physics, Chinese Academy of Sciences, Dalian 116023 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Tan Zhicheng [Thermochemistry Laboratory, Dalian Institute of Chemical physics, Chinese Academy of Sciences, Dalian 116023 (China) and College of Environmental Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China)]. E-mail: tzc@dicp.ac.cn; Shi Quan [Thermochemistry Laboratory, Dalian Institute of Chemical physics, Chinese Academy of Sciences, Dalian 116023 (China); Graduate School of the Chinese Academy of Sciences, Beijing 100049 (China); Li Yansheng [College of Environmental Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China); Yue Danting [Thermochemistry Laboratory, Dalian Institute of Chemical physics, Chinese Academy of Sciences, Dalian 116023 (China); Wang Shaoxu [College of Environmental Science and Engineering, Dalian Jiaotong University, Dalian 116028 (China)

    2007-06-15

    The low-temperature heat capacity C{sub p,m}{sup 0} of xylitol was precisely measured in the temperature range from 80 to 390K by means of a small sample automated adiabatic calorimeter. A solid-liquid phase transition was found from the experimental C{sub p}-T curve in the temperature range 360-375K with the peak heat capacity at 369.04K. The dependence of heat capacity on the temperature was fitted to the following polynomial equations with least square method. In the temperature range of 80-360K, C{sub p,m}{sup 0}(JK{sup -1}mol{sup -1})=165.87+105.19x+1.8011x{sup 2}-41.445x{sup 3}-41.851x{sup 4}+65.152x{sup =} 5+66.744x{sup 6},x=[T(K)-220]/140. In the temperature range of 370-390K, C{sub p,m}{sup 0}(JK{sup -1}mol{sup -1})=426.19+5.6366x,x=[T(K)-380]/10. The molar enthalpy and entropy of this transition were determined to be 33.26+/-0.17kJmol{sup -1} and 90.12+/-0.45JK{sup -1}mol{sup -1}, respectively. The standard thermodynamic functions (H{sub T}{sup 0}-H{sub 298.15}{sup 0}) and (S{sub T}{sup 0}-S{sub 298.15}{sup 0}), were derived from the heat capacity data in the temperature range of 80 to 390K with an interval of 5K. The standard molar enthalpy of combustion and the standard molar enthalpy of formation of the compound have been determined, {delta}{sub c}H{sub m}{sup 0} (C{sub 5}H{sub 12}O{sub 5}, cr)=(-2463.2+/-1.2)kJmol{sup -1}and {delta}{sub f}H{sub m}{sup 0} (C{sub 5}H{sub 12}O{sub 5}, cr)=(-1219.3+/-0.3)kJmol{sup -1}, by means of a precision oxygen bomb combustion calorimeter at T=298.15K. DSC and TG measurements were performed to study the thermal stability of the compound. The results were in agreement with those obtained from heat capacity measurements.

  9. Low-temperature heat capacity and the standard molar enthalpy of formation of compound chromium(III) tri(pyrazine-2-carboxylate)

    International Nuclear Information System (INIS)

    Gao, Shengli; Zhang, Sheng; Chen, Sanping; Yang, Desuo

    2012-01-01

    Highlights: ► Low-temperature heat capacities of chromium(III) tri(pyrazine-2-carboxylate) were measured from 78 to 400 K. ► Thermodynamic functions of the compound at 298.15 K were calculated based on low-temperature heat capacity. ► The standard molar enthalpy of formation of the target was determined to be −1207.86 ± 3.39 kJ mol −1 through a designed thermochemical cycle. - Abstract: Low-temperature heat capacities of the coordination compound, chromium(III) tri(pyrazine-2-carboxylate), formulated as Cr(pyza) 3 (pyza = pyrazine-2-carboxylate), were measured by a precision automated adiabatic calorimeter over the temperature range of 78–400 K. A polynomial equation of heat capacities as a function of the temperature was fitted by the least square method. Based on the fitted polynomial equation, the fitted heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated at the interval of 5 K. In accordance with a reasonable thermochemical cycle designed, the standard molar enthalpy of formation of the title complex was determined to be −1207.86 ± 3.39 kJ mol −1 by an isoperibol solution–reaction calorimeter.

  10. Heat capacity and monogamy relations in the mixed-three-spin XXX Heisenberg model at low temperatures

    Science.gov (United States)

    Zad, Hamid Arian; Movahhedian, Hossein

    2016-08-01

    Heat capacity of a mixed-three-spin (1/2,1,1/2) antiferromagnetic XXX Heisenberg chain is precisely investigated by use of the partition function of the system for which, spins (1,1/2) have coupling constant J1 and spins (1/2,1/2) have coupling constant J2. We verify tripartite entanglement for the model by means of the convex roof extended negativity (CREN) and concurrence as functions of temperature T, homogeneous magnetic field B and the coupling constants J1 and J2. As shown in our previous work, [H. A. Zad, Chin. Phys. B 25 (2016) 030303.] the temperature, the magnetic field and the coupling constants dependences of the heat capacity for such spin system have different behaviors for the entangled and separable states, hence, we did some useful comparisons between this quantity and negativities of its organized bipartite (sub)systems at entangled and separable states. Here, we compare the heat capacity of the mixed-three-spin (1/2,1,1/2) system with the CREN and the tripartite concurrence (as measures of the tripartite entanglement) at low temperature. Ground state phase transitions, and also, transition from ground state to some excited states are explained in detail for this system at zero temperature. Finally, we investigate the heat capacity behavior around those critical points in which these quantum phase transitions occur.

  11. Investigations of the trend followed in heat capacity of Re_6UO_1_2 (s) along lanthanide series

    International Nuclear Information System (INIS)

    Sahu, Manjulata; Saxena, M.K.; Rawat, Deepak; Dash, Smruti

    2017-01-01

    The compound RE_6UO_1_2 (s) (RE = Ho, Er, Tm, Yb and Lu) was synthesized by complex polymerisation method and characterised using X-ray diffraction (XRD). Heat capacity measurements of RE_6UO_1_2 (s) were performed with heat flux-type differential scanning calorimeter in the temperature range of 300-870 K. The trend in heat capacity along the rare earth series was proposed for RE_6UO_1_2 (s) and thermodynamic functions were generated. (author)

  12. Physical Properties and Specific Heat Capacity of Tamarind (Tamarindus indica Seed

    Directory of Open Access Journals (Sweden)

    A. Dauda

    2017-04-01

    Full Text Available This study investigated the effect of moisture content on physical properties and specific heat capacity of Tamarindus indica seed. Physical properties investigated were axial dimensions, one thousand seed weight, bulk and true densities, porosity, roundness and sphericity, surface area, angle of repose and static coefficient of friction. The thermal property determined was the specific heat. These properties of Tamarindus indica seed were investigated within the moisture content range of 7.55 - 10.47% (d.b. The length, width and thickness increased from 9.979 to 10.634mm, 8.909 to 10.089mm and 5.039 to 5.658mm, respectively in the above moisture range. One thousand seed weight, surface area, seed volume, true density and porosity, increased from 388.4 to 394.8g, 86.916 to 87.58cm2, 0.353 to 0.366cm3, 1217.5 to 1287.00kg/m3 and 28.22 to 33.87%, respectively, as moisture content increased in the above range, while bulk density decreased from 873.9 to 851.4kg/m3. Roundness and sphericity, and angle of repose also increased from 41 to 42.4% and 73.7 to 76.3% and 36.1 to 38.93o, respectively. Specific heat capacity values increased linearly from 589.00J/kgK to 638.61 J/kgK in the above moisture range.

  13. Low-tmperature Heat Capacities and Standard Molar Enthalpy of Formation of 4-Nitrobenzyl Alcohol

    Institute of Scientific and Technical Information of China (English)

    MENG, Qingfen; TAN, Zhicheng; WANG, Xiaohuan; DONG, Yaping; LI, Wu; SHI, Quan

    2009-01-01

    Low-temperature heat capacities of 4-nitrobenzyl alcohol (4-NBA) have been measured by a high precision automated adiabatic calorimeter over the temperature range from 78 to 396 K. The melting temperature, the molar calculated in the range from 80 to 400 K at the interval of 5 K. The constant-volume energy and standard molar en- at T=298.15 K. The standard molar enthalpy of formation has been derived, ΔfHom(C7H7NO3, s)=-(206.49± namic quantities through a Hess thermochemical cycle.

  14. Low-energy vibrational excitations in carbon nanotubes studied by heat capacity

    Science.gov (United States)

    Lasjaunias, J. C.; Biljakovic, K.; Monceau, P.; Sauvajol, J. L.

    2003-09-01

    We present low-temperature heat capacity measurements performed on two different kinds of single-walled carbon nanotube bundles which essentially differ in their mean number of tubes (NT) per bundle. For temperatures below a few kelvin, the vibrational heat capacity can be analysed as the sum of two contributions. The first one is a regular T3 phononic one, characteristic of the three-dimensional (3D) elastic character of the bundle for long-wavelength phonons. A crossover to a lower effective dimensionality appears at a few kelvin. From the 3D contribution, we estimate a mean sound velocity, and hence a mean shear modulus of the bundle. The difference in amplitude of the acoustic term and in the crossover temperature between the two samples is ascribed to the different bundle topology (i.e. NT). The second contribution, of similar amplitude in both kinds of samples, shows a peculiar power law Talpha variation (alpha < 1) indicative of localized excitations, very probably due to intrinsic structural defects of the nanotubes.

  15. Highly precise (liquid + liquid) equilibrium and heat capacity measurements near the critical point for [Bmim][BF4] + 1H, 1H, 2H, 2H perfluoroctanol

    International Nuclear Information System (INIS)

    Pérez-Sánchez, G.; Troncoso, J.; Losada-Pérez, P.; Méndez-Castro, P.; Romaní, L.

    2013-01-01

    Highlights: • Highly precise liquid–liquid curves for [Bmim][BF 4 ] + perfluoroctanol are reported. • Critical behavior of heat capacity for the same system was also characterized. • In contrast to previous results, no coulombic/solvophobic crossover for coexistence curve diameter was found. • The system criticality shows characteristics both solvophobic and coulombic. -- Abstract: Liquid + liquid equilibrium of the system [Bmim][BF 4 ] + 1H, 1H, 2H, 2H perfluoroctanol using a highly precise methodology based on refractive index measurements was experimentally determined. In addition, isobaric heat capacity near the critical point was obtained. The performance of the new refractive index set-up was successfully checked against the coexistence curve of the system dimethyl carbonate + decane, since highly accurate data are available in the literature. The choice of [Bmim][BF 4 ] + 1H, 1H, 2H, 2H perfluoroctanol was motivated by a previous experimental work, whose results suggest that this system could present characteristics of both solvophobic and coulombic behavior, which are the two categories to which an ionic system can belong. Although this was previously observed for other ionic systems, this mixture presented a very striking feature: the diameter of the coexistence curve seemed to change its criticality in the studied temperature range, from solvophobic far away to coulombic close to the critical point. The results of this work reveal that, in fact, [Bmim][BF 4 ] + 1H, 1H, 2H, 2H perfluoroctanol presents characteristics of both solvophobic and coulombic criticality, but no evidence of the observed crossover over the experimental temperature range has been found

  16. Heat capacity of amorphous and disordered Nb3Ge thin films

    International Nuclear Information System (INIS)

    Rao, N.A.H.K.

    1979-06-01

    Heat capacity measurements on 1000 to 1500A thick amorphous Nb 3 Ge and granular Al films have been carried out using an ac technique. The major goal of the experiment was to study the effect of thermal fluctuations, both above and below the superconducting transition temperature T/sub c/, in dirty, short meanfree path materials

  17. Reprint of “Heat capacity and transition behavior of sucrose by standard, fast scanning and temperature-modulated calorimetry”

    Energy Technology Data Exchange (ETDEWEB)

    Magoń, A. [Department of Chemistry, University of Technology, 35-959 Rzeszów (Poland); Wurm, A.; Schick, C. [Department of Physics, University of Rostock, 18057 Rostock (Germany); Pangloli, Ph.; Zivanovic, S. [Department of Food Science and Technology, University of Tennessee, Knoxville, TN 37996 (United States); Skotnicki, M. [Department of Pharmaceutical Technology, Poznan University of Medical Sciences, 60-780 Poznań (Poland); Pyda, M., E-mail: mpyda@utk.edu [Department of Chemistry, University of Technology, 35-959 Rzeszów (Poland)

    2015-03-10

    Highlights: • Experimental, apparent heat capacity of sucrose was investigated by advanced thermal analysis. • Vibrational heat capacity of solid state was linked with a low temperature experimental heat capacity of sucrose. • Equilibrium melting parameters of sucrose were determined. • Decomposition, superheating of crystalline sucrose during melting process were presented. • TGA, DSC, TMDSC, and FSC are useful tools for characterization of sucrose. - Abstract: The heat capacity (C{sub p}) of crystalline and amorphous sucrose was determined using standard and quasi-isothermal temperature modulated differential scanning calorimetry. The results were combined with the published data determined by adiabatic calorimetry, and the C{sub p} values are now reported for the wide 5–600 K range. The experimental C{sub p} of solid sucrose at 5–300 K was used to calculate the vibrational, solid C{sub p} based on the vibrational molecular motions. The calculated solid and liquid C{sub p} together with the transition parameters for equilibrium conditions were used as references for detailed quantitative thermal analysis of crystalline and amorphous sucrose. Melting temperature (T{sub m}) of the crystalline sucrose was identified in a broad 442–465 K range with a heat of fusion of 40–46 J/mol determined at heating rates 0.5–20 K/min, respectively. The equilibrium T{sub m} and heat of fusion of crystalline sucrose were estimated at zero heating rate as T{sup o}{sub m} = 424.4 K and ΔH{sup o}{sub f} = 32 kJ/mol, respectively. The glass transition temperature (T{sub g}) of amorphous sucrose was at 331 K with a change in C{sub p} of 267 J/(mol K) as it was estimated from reversing heat capacity by quasi-isothermal TMDSC on cooling. At heating rates less than 30 K/min, thermal decomposition occurred during melting, while at extreme rate of 1000 K/s, degradation was not observed. Data obtained by fast scanning calorimetry (FSC) at 1000 K/s, showed that T{sub m} was

  18. On the Einstein-Stern model of rotational heat capacities

    DEFF Research Database (Denmark)

    Dahl, Jens Peder

    1998-01-01

    The Einstein-Stern model for the rotational contribution to the heat capacity of a diatomic gas has recently been resuscitated. In this communication, we show that the apparent success of the model is illusory, because it is based on what has turned out to be an unfortunate comparison with experi...... with experiment. We also take exception to the possibility of assigning any meaning to the rotational zero-point energy introduced by the model. (C) 1998 American Institute of Physics. [S0021-9606(98)02448-9]....

  19. Technical-and-Economic Efficiency of Draft Enriched with Oxygen in Small-Capacity Heating Boilers

    Directory of Open Access Journals (Sweden)

    P. Ratnikov

    2013-01-01

    Full Text Available Data on complex experimental and theoretical investigations pertaining to efficiency of oxygen-enriched draft in the small-capacity heating boilers as exemplified by the plant HEIZA (HW-S-10/K have been presented in the paper. The paper provides a calculation model of heating processes in heat generator burner (as exemplified by HEIZA plant. Simulation of heating processes in the operational zone has been executed in paper. The experimental data have proved model adequacy. The calculation scheme of the plant will be used in future for determination of power and ecological efficiency of draft enrichment with oxygen.

  20. Techniques for determining thermal conductivity and heat capacity under hydrostatic pressure

    Science.gov (United States)

    Andersson, S.; Bäckström, G.

    1986-08-01

    The paper describes a method for measuring the pressure dependence of the thermal conductivity and the heat capacity of hard materials and single crystals. Two parallel metal strips are evaporated onto a flat surface of the specimen, one being used as a heater, the other as a resistance thermometer. The appropriate theoretical expression for a specimen in a liquid medium is fitted to the temperature, sampled at constant time intervals. The thermophysical properties of the liquid high-pressure medium are taken from hot-wire experiments. The procedure has been thoroughly tested at atmospheric pressure using an MgO crystal and glass as specimens and liquids of different characteristics in lieu of high-pressure medium. The accuracy attainable was found to be 3% or better, the standard deviation of the measurements being about 0.3%. The potential of the system was demonstrated by measurements on single-crystal MgO under pressures up to 1 GPa.

  1. Vapor pressure, heat capacities, and phase transitions of tetrakis(tert-butoxy)hafnium

    Czech Academy of Sciences Publication Activity Database

    Fulem, Michal; Růžička, K.

    2011-01-01

    Roč. 311, Dec. (2011), s. 25-29 ISSN 0378-3812 Institutional research plan: CEZ:AV0Z10100521 Keywords : tetrakis(tert-butoxy)hafnium * MO precursor * vapor pressure * heat capacity * vaporization enthalpy * enthalpy of fusion Subject RIV: CF - Physical ; Theoretical Chemistry Impact factor: 2.139, year: 2011

  2. Final Report: Laboratory Development of a High Capacity Gas-Fired Paper Dryer

    Energy Technology Data Exchange (ETDEWEB)

    Yaroslav Chudnovsky; Aleksandr Kozlov; Lester Sherrow

    2005-09-30

    Paper drying is the most energy-intensive and temperature-critical aspect of papermaking. It is estimated that about 67% of the total energy required in papermaking is used to dry paper. The conventional drying method uses a series of steam-heated metal cylinders that are required to meet ASME codes for pressure vessels, which limits the steam pressure to about 160 psig. Consequently, the shell temperature and the drying capacity are also limited. Gas Technology Institute together with Boise Paper Solutions, Groupe Laperrier and Verreault (GL&V) USA Inc., Flynn Burner Corporation and with funding support from the U.S. Department of Energy, U.S. natural gas industry, and Gas Research Institute is developing a high efficiency gas-fired paper dryer based on a combination of a ribbon burner and advanced heat transfer enhancement technique. The Gas-Fired Paper Dryer (GFPD) is a high-efficiency alternative to conventional steam-heated drying drums that typically operate at surface temperatures in the 300 deg F range. The new approach was evaluated in laboratory and pilot-scale testing at the Western Michigan University Paper Pilot Plant. Drum surface temperatures of more than 400 deg F were reached with linerboard (basis weight 126 lb/3000 ft2) production and resulted in a 4-5 times increase in drying rate over a conventional steam-heated drying drum. Successful GFPD development and commercialization will provide large energy savings to the paper industry and increase paper production rates from dryer-limited (space- or steam-limited) paper machines by an estimated 10 to 20%, resulting in significant capital costs savings for both retrofits and new capacity.

  3. Low-temperature heat capacities and standard molar enthalpy of formation of N-methylnorephedrine C211H17NO(s)

    Institute of Scientific and Technical Information of China (English)

    Di You-Ying; Wang Da-Qi; Shi Quan; Tan Zhi-Cheng

    2008-01-01

    This paper reports that low-temperature heat capacities of N-methylnorephedrine C11H17NO(s) have been mea- sured by a precision automated adiabatic calorimeter over the temperature range from T=78 K to T=400 K. A solid to liquid phase transition of the compound was found in the heat capacity curve in the temperature range of T=342- 364 K. The peak temperature, molar enthalpy and entropy of fusion of the substance were determined. The experimental values of the molar heat capacities in the temperature regions of T=78-342 K and T=364-400 K were fitted to two poly- nomial equations of heat capacities with the reduced temperatures by least squares method. The smoothed molar heat capacities and thermodynamic functions of N-methylnorephedrine C11H17NO(s) relative to the standard refer- ence temperature 298.15 K were calculated based on the fitted polynomials and tabulated with an interval of 5 K. The constant-volume energy of combustion of the compound at T=298.15 K was measured by means of an isoperibol preci- sion oxygen-bomb combustion calorimeter. The standard molar enthalpy of combustion of the sample was calculated. The standard molar enthalpy of formation of the compound was determined from the combustion enthalpy and other auxiliary thermodynamic data through a Hess thermochemical cycle.

  4. New waste heat district heating system with combined heat and power based on absorption heat exchange cycle in China

    International Nuclear Information System (INIS)

    Sun Fangtian; Fu Lin; Zhang Shigang; Sun Jian

    2012-01-01

    A new waste heat district heating system with combined heat and power based on absorption heat exchange cycle (DHAC) was developed to increase the heating capacity of combined heat and power (CHP) through waste heat recovery, and enhance heat transmission capacity of the existing primary side district heating network through decreasing return water temperature by new type absorption heat exchanger (AHE). The DHAC system and a conventional district heating system based on CHP (CDH) were analyzed in terms of both thermodynamics and economics. Compared to CDH, the DHAC increased heating capacity by 31% and increased heat transmission capacity of the existing primary side district heating network by 75%. The results showed that the exergetic efficiency of DHAC was 10.41% higher and the product exergy monetary cost was 36.6¥/GJ less than a CHD. DHAC is an effective way to increase thermal utilization factor of CHP, and to reduce district heating cost. - Highlights: ► Absorption heat pumps are used to recover waste heat in CHP. ► Absorption heat exchanger can reduce exergy loss in the heat transfer process. ► New waste heat heating system (DHAC) can increase heating capacity of CHP by 31%. ► DHAC can enhance heat transmission capacity of the primary pipe network by 75%. ► DHAC system has the higher exergetic efficiency and the better economic benefit.

  5. Measurements of thermal diffusivity, specific heat capacity and thermal conductivity with LFA 447 apparatus

    DEFF Research Database (Denmark)

    Zajas, Jan Jakub; Heiselberg, Per

    The LFA 447 can be successfully used for measurements of thermal diffusivity, specific heat and thermal conductivity of various samples. It is especially useful when determining the properties of materials on a very small scale. The matrix measurement mode allows for determining the local...... that the heat losses from both samples during the measurement are similar. Finally, the leveling of the samples is very important. Very small discrepancies can cause a massive error in the derivation of specific heat capacity and, as a result, thermal conductivity....

  6. 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...

  7. Debye’s temperature and heat capacity for Sr0.15Ba0.85Bi2Nb2O9 relaxor ferroelectric ceramic

    Directory of Open Access Journals (Sweden)

    A. Peláiz-Barranco

    2016-03-01

    Full Text Available A lead-free relaxor ferroelectric, Sr0.15Ba0.85Bi2Nb2O9, was synthesized via solid-state reaction and the temperature-dependence of the heat capacity was measured in a wide temperature range. The dielectric permittivity was also measured between 500Hz and 5MHz in the same temperature range. No anomaly has been detected in the heat capacity curve for the whole temperature range covered in the present experiments, while broad peaks have been observed in the dielectric permittivity with high frequency dispersion. A typical relaxor behavior has been observed from the dielectric analysis. The Debye’s temperature has showed a minimum value near the freezing temperature. The results are discussed considering the spin-glass model and the high frequency dispersion, which has been observed for the studied relaxor system.

  8. Emulsion stabilizing capacity of intact starch granules modified by heat treatment or octenyl succinic anhydride.

    Science.gov (United States)

    Timgren, Anna; Rayner, Marilyn; Dejmek, Petr; Marku, Diana; Sjöö, Malin

    2013-03-01

    Starch granules are an interesting stabilizer candidate for food-grade Pickering emulsions. The stabilizing capacity of seven different intact starch granules for making oil-in-water emulsions has been the topic of this screening study. The starches were from quinoa; rice; maize; waxy varieties of rice, maize, and barley; and high-amylose maize. The starches were studied in their native state, heat treated, and modified by octenyl succinic anhydride (OSA). The effect of varying the continuous phase, both with and without salt in a phosphate buffer, was also studied. Quinoa, which had the smallest granule size, had the best capacity to stabilize oil drops, especially when the granules had been hydrophobically modified by heat treatment or by OSA. The average drop diameter (d 32) in these emulsions varied from 270 to 50 μm, where decreasing drop size and less aggregation was promoted by high starch concentration and absence of salt in the system. Of all the starch varieties studied, quinoa had the best overall emulsifying capacity, and OSA modified quinoa starch in particular. Although the size of the drops was relatively large, the drops themselves were in many instances extremely stable. In the cases where the system could stabilize droplets, even when they were so large that they were visible to the naked eye, they remained stable and the measured droplet sizes after 2 years of storage were essentially unchanged from the initial droplet size. This somewhat surprising result has been attributed to the thickness of the adsorbed starch layer providing steric stabilization. The starch particle-stabilized Pickering emulsion systems studied in this work has potential practical application such as being suitable for encapsulation of ingredients in food and pharmaceutical products.

  9. Pressure-modulated differential scanning calorimetry. An approach to the continuous, simultaneous determination of heat capacities and expansion coefficients.

    Science.gov (United States)

    Boehm, K; Rösgen, J; Hinz, H-J

    2006-02-15

    A new method is described that permits the continuous and synchronous determination of heat capacity and expansibility data. We refer to it as pressure-modulated differential scanning calorimetry (PMDSC), as it involves a standard DSC temperature scan and superimposes on it a pressure modulation of preselected format. The power of the method is demonstrated using salt solutions for which the most accurate heat capacity and expansibility data exist in the literature. As the PMDSC measurements could reproduce the parameters with high accuracy and precision, we applied the method also to an aqueous suspension of multilamellar DSPC vesicles for which no expansibility data had been reported previously for the transition region. Excellent agreement was obtained between data from PMDSC and values from independent direct differential scanning densimetry measurements. The basic theoretical background of the method when using sawtooth-like pressure ramps is given under Supporting Information, and a complete statistical thermodynamic derivation of the general equations is presented in the accompanying paper.

  10. Heat capacity anomalies associated with structural transformations in. beta. -W and perovskite compounds

    Energy Technology Data Exchange (ETDEWEB)

    Viswanathan, R [Brookhaven National Lab., Upton, NY; Ho, J C

    1977-01-01

    The similarity of the heat capacity anomalies, often observed with structural transformations driven by soft phonons, in both ..beta..-W and perovskite compounds is discussed referring to our recent work on V/sub 3/Si and RbCaF/sub 3/.

  11. High capacity carbon dioxide sorbent

    Science.gov (United States)

    Dietz, Steven Dean; Alptekin, Gokhan; Jayaraman, Ambalavanan

    2015-09-01

    The present invention provides a sorbent for the removal of carbon dioxide from gas streams, comprising: a CO.sub.2 capacity of at least 9 weight percent when measured at 22.degree. C. and 1 atmosphere; an H.sub.2O capacity of at most 15 weight percent when measured at 25.degree. C. and 1 atmosphere; and an isosteric heat of adsorption of from 5 to 8.5 kilocalories per mole of CO.sub.2. The invention also provides a carbon sorbent in a powder, a granular or a pellet form for the removal of carbon dioxide from gas streams, comprising: a carbon content of at least 90 weight percent; a nitrogen content of at least 1 weight percent; an oxygen content of at most 3 weight percent; a BET surface area from 50 to 2600 m.sup.2/g; and a DFT micropore volume from 0.04 to 0.8 cc/g.

  12. Guide for the calculation of heating capacity and heating coils for deep tanks / Handleiding bij de berekening van verwarmingskapasiteit en spiraallengte voor dieptanks

    NARCIS (Netherlands)

    Heeden, D.J. van der; Koppenol, A.D.

    1972-01-01

    This report deals with a method for calculating the heating capacity and the length of heating coils, required for deep tanks in dry cargo ships. It is based on the theory of natural convection and on experiments, carried out on tanks loaded with mineral oils. The calculating method is set up for

  13. Enthalpy measurement of lithium meta-titanate by drop calorimetry and its derived heat capacity

    International Nuclear Information System (INIS)

    Ishioka, Rika; Mukai, Keisuke; Terai, Takayuki; Suzuki, Akihiro

    2013-01-01

    Highlights: • Li 2 TiO 3 was synthesized by a neutralizing method. • Enthalpy of Li 2 TiO 3 was measured by a drop calorimeter. • Heat capacity of Li 2 TiO 3 was derived as a function of temperature. -- Abstract: Enthalpy of Li 2 TiO 3 , which was synthesized by a neutralizing method and its Li/Ti ratio was determined to be Li/Ti ratio (mol/mol) = 1.97, was measured by a drop calorimeter, and its heat capacity was derived as a function of temperature. XRD (X-ray diffraction) analysis of the sample before and after the enthalpy measurement indicated no phase change during the measurement and a single phase of Li 2 TiO 3 was observed. The enthalpy data were expressed as H(T) − H(323.17) (J/g) = 2.2 × 10 −5 ·T 2 + 1.4·T + 2.7 × 10 4 /T − 5.6 × 10 2 (373–1273 K), where T is temperature in K. The heat capacity was calculated as C p (J/g K) = 2.2 × 2 × 10 −5 ·T + 1.4–2.7 × 10 4 /T 2 by differentiating the equation by temperature. These equations have accuracy of 3%

  14. A study on specific heat capacities of Li-ion cell components and their influence on thermal management

    Science.gov (United States)

    Loges, André; Herberger, Sabrina; Seegert, Philipp; Wetzel, Thomas

    2016-12-01

    Thermal models of Li-ion cells on various geometrical scales and with various complexity have been developed in the past to account for the temperature dependent behaviour of Li-ion cells. These models require accurate data on thermal material properties to offer reliable validation and interpretation of the results. In this context a thorough study on the specific heat capacities of Li-ion cells starting from raw materials and electrode coatings to representative unit cells of jelly rolls/electrode stacks with lumped values was conducted. The specific heat capacity is reported as a function of temperature and state of charge (SOC). Seven Li-ion cells from different manufactures with different cell chemistry, application and design were considered and generally applicable correlations were developed. A 2D thermal model of an automotive Li-ion cell for plug-in hybrid electric vehicle (PHEV) application illustrates the influence of specific heat capacity on the effectivity of cooling concepts and the temperature development of Li-ion cells.

  15. Interpretation of heat capacity anomalies: low temperature antiferromagnetism in YbSnPd2

    Science.gov (United States)

    Giudicelli, P.; Bernhoeft, N.

    2004-07-01

    Since the early experiments on critical opalescence, heat capacity anomalies, which herald continuous transitions of phase, are frequently given microscopic interpretation through an appropriate space-time correlation function. Unfortunately, the global nature of the probe often results in an ill-defined spectral representation of the integrated modes and, as such, help is often sought in the general theoretical consensus of the temporal slowing down and spatial divergence of the critical modes. In this letter it is explicitly shown how a large and continuous anomaly in the heat capacity, which announces the antiferromagnetic phase transition in YbSnPd2 as established by independent neutron diffraction techniques, is not associated with a critical slowing down of spatially correlated modes but, surprisingly, with a stiffening of spatially local excitations. It appears that the results may be of relevance in the study of other strongly correlated electron systems.

  16. Aqueous partial molar heat capacities and volumes for NaReO4 and NaTcO4

    International Nuclear Information System (INIS)

    Lemire, R.J.; Saluja, P.P.S.; Campbell, A.B.

    1989-01-01

    As part of the Canadian Nuclear Fuel Waste Management Program, data are required to model the equilibrium thermodynamic behavior of key radionuclides at temperatures above 25 degree C. A flow microcalorimeter/densimeter system has been commissioned to measure heat capacities and densities of solutions containing radioactive species. Measurements for solutions of aqueous NaReO 4 (a common analogue for NaTcO 4 ) were made at seven temperatures (15 to 100 degree C) over the concentration range 0.05 to 0.2 mol·kg -1 . Subsequently, measurements were made for NaTcO 4 solutions under similar conditions. The heat capacity and density data are analyzed using Pitzer's ion-interaction model, and values of the NaReO 4 partial molar heat capacities are compared to literature values based on integral heats of solution. The agreement between the two sets of NaReO 4 data is good below 75 degree C, but only fair at the higher temperatures. Values of the partial molar volumes have also been derived. The uncertainties introduced by using thermodynamic data for ReO 4 - , in the absence of data for TcO 4 - , are discussed

  17. Army Solid State Laser Program: Design, Operation, and Mission Analysis for a Heat-Capacity Laser

    International Nuclear Information System (INIS)

    Dane, C B; Flath, L; Rotter, M; Fochs, S; Brase, J; Bretney, K

    2001-01-01

    Solid-state lasers have held great promise for the generation of high-average-power, high-quality output beams for a number of decades. However, the inherent difficulty of scaling the active solid-state gain media while continuing to provide efficient cooling has limited demonstrated powers to 10X the diffraction limit. Challenges posed by optical distortions and depolarization arising from internal temperature gradients in the gain medium of a continuously cooled system are only increased for laser designs that would attempt to deliver the high average power in the form of high energy pulses (>25J) from a single coherent optical aperture. Although demonstrated phase-locking of multiple laser apertures may hold significant promise for the future scaling of solid-state laser systems,1 the continuing need for additional technical development and innovation coupled with the anticipated complexity of these systems effectively limits this approach for near-term multi-kW laser operation outside of a laboratory setting. We have developed and demonstrated a new operational mode for solid-state laser systems in which the cooling of the gain medium is separated in time from the lasing cycle. In ''heat-capacity'' operation, no cooling takes place during lasing. The gain medium is pumped very uniformly and the waste heat from the excitation process is stored in the solid-state gain medium. By depositing the heat on time scales that are short compared to thermal diffusion across the optical aperture, very high average power operation is possible while maintaining low optical distortions. After a lasing cycle, aggressive cooling can then take place in the absence of lasing, limited only by the fracture limit of the solid-state medium. This mode of operation is ideally suited for applications that require 1-30s engagements at very high average power. If necessary, multiple laser apertures can provide continuous operation. Land Combat mission analysis of a stressing air defense

  18. Heat capacity measurements of atoms and molecules adsorbed on evaporated metal films

    International Nuclear Information System (INIS)

    Kenny, T.W.

    1989-05-01

    Investigations of the properties of absorbed monolayers have received great experimental and theoretical attention recently, both because of the importance of surface processes in practical applications such as catalysis, and the importance of such systems to the understanding of the fundamentals of thermodynamics in two dimensions. We have adapted the composite bolometer technology to the construction of microcalorimeters. For these calorimeters, the adsorption substrate is an evaporated film deposited on one surface of an optically polished sapphire wafer. This approach has allowed us to make the first measurements of the heat capacity of submonolayer films of 4 He adsorbed on metallic films. In contrast to measurements of 4 He adsorbed on all other insulating substrates, we have shown that 4 He on silver films occupies a two-dimensional gas phase over a broad range of coverages and temperatures. Our apparatus has been used to study the heat capacity of Indium flakes. CO multilayers, 4 He adsorbed on sapphire and on Ag films and H 2 adsorbed on Ag films. The results are compared with appropriate theories. 68 refs., 19 figs

  19. Experimental Analysis of Variable Capacity Heat Pump Systems equipped with a liquid-cooled frequency inverter

    OpenAIRE

    Ebraheem, Thair

    2013-01-01

    Using an inverter-driven compressor in variable capacity heat pump systems has a main drawback, which is the extra loss in the inverter. The present experimental study aims to recover the inverter losses by using brine-cooled and water-cooled inverters, thereby improving the total efficiency of the heat pump system. In order to achieve this goal, a test rig with the air-cooled, water-cooled and brine-cooled inverters is designed and built, and a comparative analysis of the recovered heat, inv...

  20. Development of a new decay heat removal system for a high temperature gas-cooled reactor

    International Nuclear Information System (INIS)

    Sim, Yoon Sub; Park, Rae Young; Kim, Seyun

    2007-01-01

    The heat removal capacity of a RCCS is one of the major parameters limiting the capacity of a HTGR based on a passive safety system. To improve the plant economy of a HTGR, the decay heat removal capacity needs to be improved. For this, a new analysis system of an algebraic method for the performance of various RCCS designs was set up and the heat transfer characteristics and performance of the designs were analyzed. Based on the analysis results, a new passive decay heat removal system with a substantially improved performance, LFDRS was developed. With the new system, one can have an expectation that the heat removal capacity of a HTGR could be doubled

  1. Bizarre behavior of heat capacity in crystals due to interplay between two types of anharmonicities.

    Science.gov (United States)

    Yurchenko, Stanislav O; Komarov, Kirill A; Kryuchkov, Nikita P; Zaytsev, Kirill I; Brazhkin, Vadim V

    2018-04-07

    The heat capacity of classical crystals is determined by the Dulong-Petit value C V ≃ D (where D is the spatial dimension) for softly interacting particles and has the gas-like value C V ≃ D/2 in the hard-sphere limit, while deviations are governed by the effects of anharmonicity. Soft- and hard-sphere interactions, which are associated with the enthalpy and entropy of crystals, are specifically anharmonic owing to violation of a linear relation between particle displacements and corresponding restoring forces. Here, we show that the interplay between these two types of anharmonicities unexpectedly induces two possible types of heat capacity anomalies. We studied thermodynamics, pair correlations, and collective excitations in 2D and 3D crystals of particles with a limited range of soft repulsions to prove the effect of interplay between the enthalpy and entropy types of anharmonicities. The observed anomalies are triggered by the density of the crystal, changing the interaction regime in the zero-temperature limit, and can provide about 10% excess of the heat capacity above the Dulong-Petit value. Our results facilitate understanding effects of complex anharmonicity in molecular and complex crystals and demonstrate the possibility of new effects due to the interplay between different types of anharmonicities.

  2. Effect of magnetic fields on the Kondo insulator CeRhSb: Magnetoresistance and high-field heat capacity measurements

    International Nuclear Information System (INIS)

    Malik, S.K.; Menon, L.; Pecharsky, V.K.; Gschneidner, K.A. Jr.

    1997-01-01

    The compound CeRhSb is a mixed valent Ce-based compound which shows a gap in the electronic density of states at low temperatures. The gap manifests by a rise in electrical resistivity below about 8 K from which the gap energy is estimated to be about 4 K. We have carried out heat capacity measurements on this compound in various applied fields up to 9.85 T. The magnetic contribution to the heat capacity, ΔC, is found to have a maximum in ΔC/T vs T at 10 K, below which ΔC/T is linear with T. This is attributed to the fact that below this temperature, in the gapped state, the electronic density of states decreases linearly with decreasing temperature. On application of a magnetic field, the electronic specific heat coefficient γ in the gapped state increases by ∼4mJ/molK 2 . The maximum in ΔC/T vs T is observed in all fields, which shifts to lower temperatures ∼1K at 5.32 T and raises again at 9.85 T to about the same values as at H=0T. This suggests that the gap exists for all fields up to 9.85 T. Above 10 K, in the mixed-valent state, ΔC/T vs T decreases with increasing temperature in zero field. There is hardly any effect of application of field in the mixed-valent state. We have also carried out magnetoresistance measurements on CeRhSb up to fields of 5.5 T at 2, 4.5, 10, 20, and 30 K. The magnetoresistance in CeRhSb is positive at temperatures of 4.5 K and above, in applied fields up to 5.5 T. At 5.5 T, the magnetoresistance is maximum at 4.5 K (6%) and decreases with increasing temperature. The observation of the maximum is consistent with the observation of a maximum in ΔC/T vs T and is due to a change in the density of states. At a temperature of 2 K, a negative magnetoresistance is observed for magnetic fields greater than ∼3.5T which suggests reduction in the gap. copyright 1997 The American Physical Society

  3. Thermoeconomic Evaluation of Modular Organic Rankine Cycles for Waste Heat Recovery over a Broad Range of Heat Source Temperatures and Capacities

    Directory of Open Access Journals (Sweden)

    Markus Preißinger

    2017-02-01

    Full Text Available Industrial waste heat recovery by means of an Organic Rankine Cycle (ORC can contribute to the reduction of CO2 emissions from industries. Before market penetration, high efficiency modular concepts have to be developed to achieve appropriate economic value for industrial decision makers. This paper aims to investigate modularly designed ORC systems from a thermoeconomic point of view. The main goal is a recommendation for a suitable chemical class of working fluids, preferable ORC design and a range of heat source temperatures and thermal capacities in which modular ORCs can be economically feasible. For this purpose, a thermoeconomic model has been developed which is based on size and complexity parameters of the ORC components. Special emphasis has been laid on the turbine model. The paper reveals that alkylbenzenes lead to higher exergetic efficiencies compared to alkanes and siloxanes. However, based on the thermoeconomic model, the payback periods of the chemical classes are almost identical. With the ORC design, the developed model and the boundary conditions of this study, hexamethyldisiloxane is a suitable working fluid and leads to a payback period of less than 5 years for a heat source temperature of 400 to 600 °C and a mass flow rate of the gaseous waste heat stream of more than 4 kg/s.

  4. Apparent and partial molal heat capacities of aqueous rare earth nitrate solutions at 250C

    International Nuclear Information System (INIS)

    Spedding, F.H.; Baker, J.L.; Walters, J.P.

    1979-01-01

    Specific heats of aqueous solutions of the trinitrates of La, Pr, Nd, Sm, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu were measured from 0.1 m to saturation at 25 0 C. Apparent molal heat capacities, phi/sub cp/, were calculated for these solutions, and empirical polynomial equations were obtained which expressed phi/sub cp/ as a function of m/sup 1/2/ for each salt. The partial molal heat capacities of the solvent, anti C 1 /sub p/, and solute, anti C 2 /sub p/, were calculated from these equations. Unlike chloride and perchlorate data reported earlier, values of anti C 1 /sub p/ for nitrate solutions across the rare earth series did not show a two series effect. Instead, anti C 1 /sub p/ values at lower concentrations (0.5 and 1.0 m) appear correlated with reported first formation constants for rare earth-nitrate complexes. 31 references, 9 figures, 2 tables

  5. On the development of high temperature ammonia-water hybrid absorption-compression heat pumps

    DEFF Research Database (Denmark)

    Jensen, Jonas Kjær; Markussen, Wiebke Brix; Reinholdt, Lars

    2015-01-01

    Ammonia-water hybrid absorption-compression heat pumps (HACHP) are a promising technology for development of ecient high temperature industrial heat pumps. Using 28 bar components HACHPs up to 100 °C are commercially available. Components developed for 50 bar and 140 bar show that these pressure...... limits may be possible to exceed if needed for actual applications. Feasible heat supply temperatures using these component limits are investigated. A feasible solution is defined as one that satisfies constraints on the COP, low and high pressure, compressor discharge temperature, vapour water content...... and volumetric heat capacity. The ammonia mass fraction and the liquid circulation ratio both influence these constraining parameters. The paper investigates feasible combinations of these parameters through the use of a numerical model. 28 bar components allow temperatures up to 111 °C, 50 bar up to 129°C...

  6. Seasonal and geographical variation in heat tolerance and evaporative cooling capacity in a passerine bird.

    Science.gov (United States)

    Noakes, Matthew J; Wolf, Blair O; McKechnie, Andrew E

    2016-03-01

    Intraspecific variation in avian thermoregulatory responses to heat stress has received little attention, despite increasing evidence that endothermic animals show considerable physiological variation among populations. We investigated seasonal (summer versus winter) variation in heat tolerance and evaporative cooling in an Afrotropical ploceid passerine, the white-browed sparrow-weaver (Plocepasser mahali; ∼ 47 g) at three sites along a climatic gradient with more than 10 °C variation in mid-summer maximum air temperature (Ta). We measured resting metabolic rate (RMR) and total evaporative water loss (TEWL) using open flow-through respirometry, and core body temperature (Tb) using passive integrated transponder tags. Sparrow-weavers were exposed to a ramped profile of progressively higher Ta between 30 and 52 °C to elicit maximum evaporative cooling capacity (N=10 per site per season); the maximum Ta birds tolerated before the onset of severe hyperthermia (Tb ≈ 44 °C) was considered to be their hyperthermia threshold Ta (Ta,HT). Our data reveal significant seasonal acclimatisation of heat tolerance, with a desert population of sparrow-weavers reaching significantly higher Ta in summer (49.5 ± 1.4 °C, i.e. higher Ta,HT) than in winter (46.8 ± 0.9 °C), reflecting enhanced evaporative cooling during summer. Moreover, desert sparrow-weavers had significantly higher heat tolerance and evaporative cooling capacity during summer compared with populations from more mesic sites (Ta,HT=47.3 ± 1.5 and 47.6 ± 1.3 °C). A better understanding of the contributions of local adaptation versus phenotypic plasticity to intraspecific variation in avian heat tolerance and evaporative cooling capacity is needed for modelling species' responses to changing climates. © 2016. Published by The Company of Biologists Ltd.

  7. Loop heat pipes - highly efficient heat-transfer devices for systems of sun heat supply

    Energy Technology Data Exchange (ETDEWEB)

    Maydanik, Yu. [Ural Branch of the Russian Academy of Sciences, Ekaterinburg (Russian Federation). Inst. of Thermophysics

    2004-07-01

    Loop heat pipes (LHPs) are hermetic heat-transfer devices operating on a closed evaporation-condensation cycle with the use of capillary pressure for pumping the working fluid [1]. In accordance with this, they possess all the main advantages of conventional heat pipes, but, as distinct from the latter, have a considerably higher heat-transfer capacity, especially when operating in the ''antigravity'' regime, when heat is transferred from above downwards. Besides, LHPs possess a higher functional versatility, are adaptable to different operating conditions and provide great scope for various design embodiments. This is achieved at the expense of both the original design of the device and the properties of the wick - a special capillary structure used for the creation of capillary pressure. The LHP schematic diagram is given in Fig. 1. The device contains an evaporator and a condenser - heat exchanger connected by means of smooth-walled pipe-lines with a relatively small diameter intended for separate motion of vapor and liquid. At present loop heat pipes are most extensively employed in thermoregulation systems of spacecrafts. Miniature LHPs are used for cooling electronics and computers. At the same time there exists a considerable potential of using these devices for the recovery of low-grade (waste) heat from different sources, and also in systems of sun heat supply. In the latter case LHPs may serve as an efficient heat-transfer link between a sun collector and a heat accumulator, which has a low thermal resistance and does not consume any additional energy for pumping the working fluid between them. (orig.)

  8. Liquid-liquid phase equilibrium and heat capacity of binary solution {2-propanol + 1-octyl-3-methylimidazolium hexafluorophosphate}

    International Nuclear Information System (INIS)

    Guo, Yimin; Zhang, Xianshuo; Xu, Chen; Shen, Weiguo

    2017-01-01

    Highlights: • Liquid-liquid equilibrium of binary {2-propanol + RTIL} solution was measured. • The critical exponents were deduced and found to belong to 3D-Ising universality. • Asymmetry of the coexistence curve was analyzed by the complete scaling theory. • The dependences of critical parameters on the permittivity of alkanols were discussed. - Abstract: The liquid-liquid coexistence curve and the heat capacity for binary solution of {2-propanol + 1-octyl-3-methylimidazolium hexafluorophosphate} have been precisely measured. The values of the critical exponents α and β, characterizing the critical anomalies of the heat capacity and the coexistence curve respectively, were deduced and found to be consistent with theoretical predictions. The asymmetric behavior of the diameter of the coexistence curve was studied in the frame of the complete scaling theory, demonstrating that the heat capacity related term is of importance. Furthermore, the restricted primitive model (RPM) was used to calculate the reduced upper consolute temperature and density, which together with a comparative larger value of A + indicated a character of solvophobic criticality.

  9. Commercial high efficiency dehumidification systems using heat pipes

    Energy Technology Data Exchange (ETDEWEB)

    1993-09-01

    An improved heat pipe design using separately connected two-section one-way flow heat pipes with internal microgrooves instead of wicks is described. This design is now commercially available for use to increase the dehumidification capacity of air conditioning systems. The design also includes a method of introducing fresh air into buildings while recovering heat and controlling the humidity of the incoming air. Included are applications and case studies, load calculations and technical data, and installation, operation, and maintenance information.

  10. High temperature heat exchange: nuclear process heat applications

    International Nuclear Information System (INIS)

    Vrable, D.L.

    1980-09-01

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

  11. 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.

  12. Identification of pitfalls in the analysis of heat capacity changes of β-lactoglobulin A

    NARCIS (Netherlands)

    Teeffelen, A.M.M. van; Meinders, M.B.J.; Jongh, H.H.J. de

    2005-01-01

    Information on changes in heat capacity (ΔCp) of proteins upon unfolding is used frequently in literature to understand possible follow-up reactions of protein denaturation, like their aggregation propensity. This thermodynamic property is intrinsic to the protein's architecture and unfolding and

  13. Thermodynamics of micellization from heat-capacity measurements.

    Science.gov (United States)

    Šarac, Bojan; Bešter-Rogač, Marija; Lah, Jurij

    2014-06-23

    Differential scanning calorimetry (DSC), the most important technique for studying the thermodynamics of structural transitions of biological macromolecules, is seldom used in quantitative thermodynamic studies of surfactant micellization/demicellization. The reason for this could be ascribed to an insufficient understanding of the temperature dependence of the heat capacity of surfactant solutions (DSC data) in terms of thermodynamics, which leads to problems with the design of experiments and interpretation of the output signals. We address these issues by careful design of DSC experiments performed with solutions of ionic and nonionic surfactants at various surfactant concentrations, and individual and global mass-action model analysis of the obtained DSC data. Our approach leads to reliable thermodynamic parameters of micellization for all types of surfactants, comparable with those obtained by using isothermal titration calorimetry (ITC). In summary, we demonstrate that DSC can be successfully used as an independent method to obtain temperature-dependent thermodynamic parameters for micellization. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. Compact heat exchanger for power plants

    International Nuclear Information System (INIS)

    Kinnunen, L.

    2001-01-01

    Vahterus Oy, located at Kalanti, has manufactured heat exchangers since the beginning of 1990s. About 90% of the equipment produced are exported. In the PSHE (Plate and Shell) solution of the Vahterus heat exchanger the heat is transferred by round plated welded to form a compact package, which is assembled into a cylindrical steel casing. The heat exchanger contains no gaskets or soldered joints, which eliminates the leak risks. Traditional heat exchanges are usually operated at higher temperatures and pressures, but the heat transfer capacities of them are lower. Plate heat exchangers, on the other hand, are efficient, but the application range of them is narrow. Additionally, the rubber gasket of the heat exchange plates, sealing the joints of the heat exchanging plates, does not stand high pressures or temperatures, or corroding fluids. The new welded plate heat exchanger combine the pressure and temperature resistance of tube heat exchangers and the high heat exchange capacity of plate heat exchangers. The new corrosion resisting heat exchanger can be applied for especially hard conditions. The operating temperature range of the PSHE heat exchanger is - 200 - 900 deg C. The pressure resistance is as high as 100 bar. The space requirement of PSHE is only one tenth of the space requirement of traditional tube heat exchangers. Adjusting the number of heat exchanging plates can change the capacity of the heat exchanger. Power range of the heat exchanger can be as high as 80 MW. Due to the corrosion preventive construction and the small dimension the PSHE heat exchanger can be applied for refrigerators using ammonia as refrigerant. These kinds of new Vahterus heat exchangers are in use in 60 countries in more than 2000 refrigerators

  15. Analysis of chiller units capacity for different heat loads considering variation of ambient air and cooling water temperature

    International Nuclear Information System (INIS)

    Coman, Aurelia Camelia; Tenescu, Mircea

    2010-01-01

    The paper purpose is to analyze the chiller units capacity to determine whether they can cope with high air and cooling water temperatures during summer time to remove heat loads imposed from Heating, Ventilation and Air Conditioning (HVAC) units in a CANDU 6 Nuclear Power Plant. The starting point is calculation of the overall heat transfer coefficient at the evaporator and condenser. They are used in heat balance equations of heat exchangers. A mathematical model was developed that simulates the refrigeration cycle to assess the response of chilled water system and its performance at different heat loads. In this analysis there were calculated values for inlet/outlet chilled water temperature and the refrigerant cycle thermodynamic parameters (condenser and evaporator pressure/temperature, refrigerant mass flowrate, refrigerant quality at the evaporator, refrigerant vapour superheated temperature at the compressor outlet, refrigerant subcooled temperature at the condenser outlet). To find the adequate functioning parameters of the installation, the MathCAD 13 software was used in all cases analyzed. The behaviour of the chiller units was investigated by examining the variation of three basic parameters, namely: - cooling water (river water) temperature; - air temperature; - heat load. The simultaneous variation of these three independent parameters allows to identify the actual chillers unit operating point (including chiller trip). (authors)

  16. Low temperature heat capacity measurements of the spin-liquid states of hydrogenated and deuterated κ-(BEDT-TTF)2Cu2(CN)3

    International Nuclear Information System (INIS)

    Yamashita, S.; Yamamoto, T.; Nakazawa, Y.

    2010-01-01

    Heat capacity measurements of organic triangular lattice compound κ-(BEDT-TTF) 2 Cu 2 (CN) 3 were performed to discuss the low energy excitations from the spin-liquid ground states. Existence of the T-linear electronic coefficient with finite electronic heat capacity coefficient γ was confirmed in three different samples from different batches, although small sample dependence was observed in the absolute values of the heat capacities. Concerning the sample in which hydrogen atoms in ethylene group in BEDT-TTF molecule have been substituted by deuterons, we have observed almost similar thermodynamic behavior as the hydrogenated sample. The absence of drastic change of electronic properties of this compound is consistent with the electronic phase diagram given by Kurosaki et al. [11] (Phys. Rev. Lett. 95 (2005) 17001). The obtained data are well consistent with the previous heat capacity experiments. The existence of the γ term demonstrates that the excitations from the quantum spin-liquid states show a gapless behavior at least down to 0.7 K.

  17. Antioxidant capacity and fatty acids characterization of heat treated cow and buffalo milk.

    Science.gov (United States)

    Khan, Imran Taj; Nadeem, Muhammad; Imran, Muhammad; Ayaz, Muhammad; Ajmal, Muhammad; Ellahi, Muhammad Yaqoob; Khalique, Anjum

    2017-08-24

    Antioxidant capacity of milk is largely due to vitamins A, E, carotenoids, zinc, selenium, superoxide dismutase, catalase, glutathione peroxidase and enzyme systems. Cow milk has antioxidant capacity while the antioxidant capacity of buffalo milk has been studied in a limited way. The information regarding the effect of pasteurization and boiling on antioxidant capacity of cow and buffalo milk is also scared. Cow and buffalo milk was exposed to two different heat treatments i.e. 65 °C for 30 min and boiling for 1 min. After heat treatments, milk samples were cooled down to 4 °C packaged in transparent 250 ml polyethylene PET bottles and stored at 4 °C for 6 days. Milk composition, total flavonoid content, total antioxidant capacity, reducing power, DPPH free radical scavenging activity, antioxidant activity in linoleic acid, vitamin C, A, E, selenium, Zinc, fatty acid profile, peroxide value and sensory characteristics were studied in raw, pasteurized and boiled cow and buffalo milk at 0, 3 and 6 days of storage period. Total antioxidant capacity (TAC) of raw, pasteurized and boiled milk for cow (42.1, 41.3 and 40.7%) and buffalo (58.4, 57.6 and 56.5%) samples was found, respectively. Reducing power (RP) of raw cow and buffalo milk was 6.74 and 13.7 while pasteurization and boiling did not showed significant effect on RP of both cow and buffalo milk. DPPH activity of raw, pasteurized and boiled milk for cow (24.3, 23.8 and 23.6%) and buffalo (31.8, 31.5 and 30.4%) samples was noted, respectively. Storage period up to 3 days was non-significant while DPPH assay after 6 days of storage period indicated significant decline in antioxidant activity of milk samples. Antioxidant activity in linoleic acid (AALA) of buffalo and cow milk were recorded 11.7 and 17.4%, respectively. Pasteurization and boiling did not showed any impact on antioxidant capacity of cow and buffalo milk. The Loss of vitamin C in pasteurization (40 and 42%) and boiling (82 and 61%) of

  18. Heat capacity and thermodynamic properties of N-(2-cyanoethyl) aniline (C9H10N2)

    International Nuclear Information System (INIS)

    Tian Qifeng; Tan Zhicheng; Shi Quan; Xu Fen; Sun Lixian; Zhang Tao

    2005-01-01

    The low temperature heat capacities of N-(2-cyanoethyl)aniline were measured with an automated adiabatic calorimeter over the temperature range from 83 to 353 K. The temperature corresponding to the maximum value of the apparent heat capacity in the fusion interval, molar enthalpy and entropy of fusion of this compound were determined to be 323.33 ± 0.13 K, 19.4 ± 0.1 kJ mol -1 and 60.1 ± 0.1 J K -1 mol -1 , respectively. Using the fractional melting technique, the purity of the sample was determined to be 99.0 mol% and the melting temperature for the tested sample and the absolutely pure compound were determined to be 323.50 and 323.99 K, respectively. A solid-to-solid phase transition occurred at 310.63 ± 0.15 K. The molar enthalpy and molar entropy of the transition were determined to be 980 ± 5 J mol -1 and 3.16 ± 0.02 J K -1 mol -1 , respectively. The thermodynamic functions of the compound [H T - H 298.15 ] and [S T - S 298.15 ] were calculated based on the heat capacity measurements in the temperature range of 83-353 K with an interval of 5 K

  19. Low-temperature heat capacities and standard molar enthalpy of formation of 4-(2-aminoethyl)-phenol(C8H11NO)

    Institute of Scientific and Technical Information of China (English)

    Di You-Ying; Kong Yu-Xia; Yang Wei-Wei; Tan Zhi-Cheng

    2008-01-01

    This paper reports that low-temperature heat capacities of 4-(2-aminoethyl)-phenol(C8H11NO)are measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 400 K.A polynomial equation of heat capacities as a function of the temperature was fitted by the least square method.Based on the fitted polynomial,the smoothed heat capacities and thermodynamic functions of the compound relative to the standard reference temperature 298.15 K were calculated and tabulated at the interval of 5 K.The energy equivalent,gcalor,of the oxygen-bomb The constant-volume energy of combustion of the compound at T=298.15 K was measured by a precision oxygen-bomb combustion and other thermodynamic principles.Finally,the standard molar enthalpy of formation of the compound

  20. Heat capacities and asymmetric criticality of the (liquid + liquid) coexistence curves for {dimethyl carbonate + n-undecane, or n-tridecane}

    International Nuclear Information System (INIS)

    Chen, Zhiyun; Shi, Aiqin; Liu, Shixia; Yin, Tianxiang; Shen, Weiguo

    2014-01-01

    Highlights: • Coexistence curves of dimethyl carbonate + n-undecane (or + n-tridecane) were measured. • Isobaric heat capacity per unit volume of critical binary solutions dimethyl carbonate + n-undecane (or + n-tridecane) were determined. • The critical exponent β are consistent with the 3D-Ising value. • The asymmetry of the coexistence curves were discussed by the complete scaling theory. - Abstract: The (liquid + liquid) coexistences and the critical behavior of isobaric heat capacity per unit volume for critical binary solutions {dimethyl carbonate + n-undecane, or n-tridecane} have been studied. The critical exponents β and α were deduced and found to be consistent with the 3D-Ising values. The critical amplitudes were determined and used to test the asymmetric criticality of coexistence curves. It was found that the heat capacity does play an important role in describing the asymmetric criticality of the coexistence curves

  1. Evaluation on the heat removal capacity of the first wall for water cooled breeder blanket of CFETR

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Kecheng, E-mail: jiangkecheng@ipp.ac.cn; Cheng, Xiaoman; Chen, Lei; Huang, Kai; Ma, Xuebin; Liu, Songlin

    2016-02-15

    Highlights: • Heat removal capacity of the FW is evaluated under BWR, PWR and He coolant inlet conditions. • Heat transfer property of the gas–liquid two phase and the two boiling crises are analyzed. • Heat removal capacity of water is larger than helium coolant. - Abstract: The water cooled ceramic breeder blanket (WCCB) is being researched for Chinese Fusion Engineering Test Reactor (CFETR). As an important component of the blanket, the FW should satisfy with the thermal requirements in any case. In this paper, three parameters including the heat removal capacity, coolant pressure drop as well as the temperature rise of the FW were investigated under different coolant velocity and heat flux from the plasma. Using the same first wall structure, two main water cooled schemes including Boiling Water Reactor (BWR, 7 MPa pressure and 265 °C temperature inlet) and Pressurized Water Reactor (PWR, 15 MPa pressure and 285 °C temperature inlet) conditions are discussed in the thermal hydraulic calculation. For further research, the thermal hydraulic characteristics of using helium as coolant (8 MPa pressure, 300 °C temperature inlet) are also explored to provide CFETR blanket design with more useful data supports. Without regard to the outlet coolant condition requirements of the blanket, the results indicate that the ultimate heat flux that the FW can resist is 2.2 MW/m{sup 2} at velocity of 5 m/s for BWR, 2.0 MW/m{sup 2} at velocity of 5 m/s for PWR and 0.87 MW/m{sup 2} for helium at velocity 100 m/s under the chosen operation condition. The detrimental departure from nucleate boiling (DNB) crisis would occur at the velocity of 1 m/s under the heat flux of 3 MW/m{sup 2} and dry out crisis appears at the velocity of less than 0.2 m/s with the heat flux of more than 1 MW/m{sup 2} for BWR. The further blanket/FW optimization design is provided with more useful data references according to the abundant calculation results.

  2. Heat capacity and phonon mean free path in the biocarbon matrix of beech

    Science.gov (United States)

    Parfen'eva, L. S.; Orlova, T. S.; Smirnov, B. I.; Smirnov, I. A.; Misiorek, H.; Wlosewicz, D.; Jezowski, A.

    2011-08-01

    The heat capacity at constant pressure C p of the biocarbon matrix prepared at a beech wood carbonization temperature of 1000°C has been measured in the temperature range 80-300 K. It has been shown that, in the temperature range 90-180 K, the heat capacity is C ˜ T 0.8 and, at T = 190-300 K, it is C p ˜ T 1.2. The phonon mean free path l( T) in the biocarbon matrix has been calculated using the obtained dependences C p ( T), our previous results on the phonon thermal conductivity of the carbon framework of this biocarbon matrix, and data available in the literature on the sound velocity in the matrix. It has been demonstrated that, in the temperature range 200-300 K, the mean value of l is ˜ 15 Å, which is close to the sizes of nanocrystallites ("carbon fragments") of ˜ 12Å, obtained earlier from X-ray diffraction data for the carbon matrix under consideration. These nanocrystallites participate in the formation of the carbon framework of the beech wood biocarbon matrix.

  3. Phonon Density of States and Heat Capacity of La3-xTe4

    International Nuclear Information System (INIS)

    Delaire, Olivier A.; May, Andrew F.; McGuire, Michael A.; Porter, Wallace D.; Lucas, Matthew S.; Stone, Matthew B.; Abernathy, Douglas L.; Snyder, G.J.

    2009-01-01

    The phonon density of states (DOS) of La 3-x Te 4 compounds (x=0.0, 0.18, 0.32) was measured at 300, 520, and 780 K, using inelastic neutron scattering. A significant stiffening of the phonon DOS, and a large broadening of features were observed upon introduction of vacancies on La sites (increasing x). Heat capacity measurements were performed at temperatures ∼1.85 ≤ T ≤ 1200 K and were analyzed to quantify the contributions of phonons and electrons. The Debye temperature and the electronic coefficient of heat capacity determined from these measurements are consistent with the neutron scattering results, and with previously reported first-principles calculations. Our results indicate that La vacancies in La 3-x Te 4 strongly scatter phonons, and this source of scattering appears to be independent of temperature. The stiffening of the phonon DOS induced by the introduction of vacancies is explained in terms of the electronic structure and the change in bonding. The temperature dependence of the phonon DOS is captured satisfactorily by the quasiharmonic approximation.

  4. CSTI High Capacity Power

    International Nuclear Information System (INIS)

    Winter, J.M.

    1989-01-01

    The SP-100 program was established in 1983 by DOD, DOE, and NASA as a joint program to develop the technology necessary for space nuclear power systems for military and civil application. During FY-86 and 87, the NASA SP-100 Advanced Technology Program was devised to maintain the momentum of promising technology advancement efforts started during Phase 1 of SP-100 and to strengthen, in key areas, the chances for successful development and growth capability of space nuclear reactor power systems for future space applications. In FY-88, the Advanced Technology Program was incorporated into NASA's new Civil Space Technology Initiative (CSTI). The CSTI Program was established to provide the foundation for technology development in automation and robotics, information, propulsion, and power. The CSTI High Capacity Power Program builds on the technology efforts of the SP-100 program, incorporates the previous NASA SP-100 Advanced Technology project, and provides a bridge to NASA Project Pathfinder. The elements of CSTI High Capacity Power development include Conversion Systems, Thermal Management, Power Management, System Diagnostics, and Environmental Interactions. Technology advancement in all areas, including materials, is required to assure the high reliability and 7 to 10 year lifetime demanded for future space nuclear power systems. The overall program will develop and demonstrate the technology base required to provide a wide range of modular power systems as well as allowing mission independence from solar and orbital attitude requirements. Several recent advancements in CSTI High Capacity power development will be discussed

  5. Improving Reversible Capacities of High-Surface Lithium Insertion Materials – The Case of Amorphous TiO2

    International Nuclear Information System (INIS)

    Ganapathy, Swapna; Basak, Shibabrata; Lefering, Anton; Rogers, Edith; Zandbergen, Henny W.; Wagemaker, Marnix

    2014-01-01

    Chemisorbed water and solvent molecules and their reactivity with components from the electrolyte in high-surface nano-structured electrodes remains a contributing factor toward capacity diminishment on cycling in lithium ion batteries due to the limit in maximum annealing temperature. Here, we report a marked improvement in the capacity retention of amorphous TiO 2 by the choice of preparation solvent, control of annealing temperature, and the presence of surface functional groups. Careful heating of the amorphous TiO 2 sample prepared in acetone under vacuum lead to complete removal of all molecular solvent and an improved capacity retention of 220 mAh/g over 50 cycles at a C/10 rate. Amorphous TiO 2 when prepared in ethanol and heated under vacuum showed an even better capacity retention of 240 mAh/g. From Fourier transform infra-red spectroscopy and electron energy loss spectroscopy measurements, the improved capacity is attributed to the complete removal of ethanol and the presence of very small fractions of residual functional groups coordinated to oxygen-deficient surface titanium sites. These displace the more reactive chemisorbed hydroxyl groups, limiting reaction with components from the electrolyte and possibly enhancing the integrity of the solid electrolyte interface. The present research provides a facile strategy to improve the capacity retention of nano-structured electrode materials.

  6. Avian thermoregulation in the heat: evaporative cooling capacity of arid-zone Caprimulgiformes from two continents.

    Science.gov (United States)

    Talbot, William A; McWhorter, Todd J; Gerson, Alexander R; McKechnie, Andrew E; Wolf, Blair O

    2017-10-01

    Birds in the order Caprimulgiformes (nightjars and allies) have a remarkable capacity for thermoregulation over a wide range of environmental temperatures, exhibiting pronounced heterothermy in cool conditions and extreme heat tolerance at high environmental temperatures. We measured thermoregulatory responses to acute heat stress in three species of Caprimulgiformes that nest in areas of extreme heat and aridity, the common poorwill ( Phalaenoptilus nuttallii : Caprimulgidae) and lesser nighthawk ( Chordeiles acutipennis : Caprimulgidae) in the Sonoran Desert of Arizona, and the Australian owlet-nightjar ( Aegotheles cristatus : Aegothelidae) in the mallee woodlands of South Australia. We exposed wild-caught birds to progressively increasing air temperatures ( T a ) and measured resting metabolic rate (RMR), evaporative water loss (EWL), body temperature ( T b ) and heat tolerance limit (HTL; the maximum T a reached). Comparatively low RMR values were observed in all species (0.35, 0.36 and 0.40 W for the poorwill, nighthawk and owlet-nightjar, respectively), with T b approximating T a at 40°C and mild hyperthermia occurring as T a reached the HTL. Nighthawks and poorwills reached HTLs of 60 and 62°C, respectively, whereas the owlet-nightjar had a HTL of 52°C. RMR increased gradually above minima at T a of 42, 42 and 35°C, and reached 1.7, 1.9 and 2.0 times minimum resting values at HTLs in the poorwill, nighthawk and owlet-nightjar, respectively. EWL increased rapidly and linearly as T a exceeded T b and resulted in maximum rates of evaporative heat dissipation equivalent to 237-424% of metabolic heat production. Bouts of gular flutter resulted in large transient increases in evaporative heat loss (50-123%) accompanied by only small increments in RMR (<5%). The cavity-nesting/roosting owlet-nightjar had a lower HTL and less efficient evaporative cooling compared with the species that nest and/or roost on open desert surfaces. The high efficiency of gular

  7. DEVELOPMENT OF A HIGH PERFORMANCE COLD CLIMATE HEAT PUMP

    Energy Technology Data Exchange (ETDEWEB)

    Horton, W. Travis [Purdue University; Groll, Eckhard A. [Purdue University; Braun, James E. [Purdue University

    2014-06-01

    The primary goals of the proposed project were to develop, test, and evaluate a high performance and cost-effective vapor compression air-source heat pump for use in cold climate regions. Vapor compression heat pumps are a proven technology, and have been used for many years to meet heating requirements for buildings in residential, commercial, and industrial applications. However, in climate regions that experience very low outdoor ambient temperatures both the heating capacity and coefficient of performance (COP) of traditional air-source vapor compression heat pumps drops dramatically with a decrease in the outdoor air temperature. The efficiency of heat pumping equipment has improved substantially over the past 20 years; however, the efficiencies of the highest rated equipment on the market are approaching practical limits that cannot be surpassed without modifications to the basic cycle and possibly the use of additional hardware. In this report, three technologies to improve the efficiency of vapor compression systems are described. These are a) vapor injected compression, b) oil flooded compression and c) hybrid flow control of the evaporator. Compressor prototypes for both, oil flooded and vapor injected compression were developed by Emerson Climate Technologies. For the oil flooded compressor, the oil injection port location was optimized and an internal oil separator was added using several design iterations. After initial testing at Emerson Climate Technologies, further testing was done at Purdue University, and compressor models were developed. These models were then integrated into a system model to determine the achievable improvement of seasonal energy efficiency (SEER) for Minneapolis (Minnesota) climate. For the oil flooded compression, a 34% improvement in seasonal energy efficiency was found while a 21% improvement in seasonal energy efficiency ratio was found for the vapor injected compression. It was found that one benefit of both tested

  8. High-frequency current application in industry for heating of non-metallic materials. Session 4 N. 4. 2

    Energy Technology Data Exchange (ETDEWEB)

    Bezmenov, F V; Dashkevich, I P; Dobrovolskaya, V I; Fedorova, I G; Shamov, A N; Vasiliev, A S

    1984-01-01

    Large scale industrial development of induction heating requires high operating efficiencies. This resulted in extending the research and development in the fiels of static frequency inverters and its circuits. Medium frequency sub-stations for centralized feeding of heating units are widely introduced into industry. Techno-economical parameters of induction heating strongly depend of proper choice and monitoring of heating conditions. Systems of analog and digital control for electro-heat processes and for power source operational conditions are considered. Large attention is drawn to the development of high capacity radio frequency power source for welding. Some questions arising from the computer design techniques adopted for industrial heating uits and power sources are described. Modes of combined solution of two and three-dimensional systems as well as hydrodynamic problems are presented.

  9. New equations for density, entropy, heat capacity, and potential temperature of a saline thermal fluid

    Science.gov (United States)

    Sun, Hongbing; Feistel, Rainer; Koch, Manfred; Markoe, Andrew

    2008-10-01

    A set of fitted polynomial equations for calculating the physical variables density, entropy, heat capacity and potential temperature of a thermal saline fluid for a temperature range of 0-374 °C, pressure range of 0.1-100 MPa and absolute salinity range of 0-40 g/kg is established. The freshwater components of the equations are extracted from the recently released tabulated data of freshwater properties of Wagner and Pruß [2002. The IAPWS formulation 1995 for the thermodynamic properties of ordinary water substance for general and scientific use. Journal of Physical and Chemical Reference Data 31, 387-535]. The salt water component of the equation is based on the near-linear relationship between density, salinity and specific heat capacity and is extracted from the data sets of Feistel [2003. A new extended Gibbs thermodynamic potential of seawater. Progress in Oceanography 58, 43-114], Bromley et al. [1970. Heat capacities and enthalpies of sea salt solutions to 200 °C. Journal of Chemical and Engineering Data 15, 246-253] and Grunberg [1970. Properties of sea water concentrates. In: Third International Symposium on Fresh Water from the Sea, vol. 1, pp. 31-39] in a temperature range 0-200 °C, practical salinity range 0-40, and varying pressure and is also calibrated by the data set of Millero et al. [1981. Summary of data treatment for the international high pressure equation of state for seawater. UNESCO Technical Papers in Marine Science 38, 99-192]. The freshwater and salt water components are combined to establish a workable multi-polynomial equation, whose coefficients were computed through standard linear regression analysis. The results obtained in this way for density, entropy and potential temperature are comparable with those of existing models, except that our new equations cover a wider temperature—(0-374 °C) than the traditional (0-40 °C) temperature range. One can apply these newly established equations to the calculation of in-situ or

  10. Capacity Bounds and High-SNR Capacity of MIMO Intensity-Modulation Optical Channels

    KAUST Repository

    Chaaban, Anas

    2018-02-19

    The capacity of the intensity modulation direct detection multiple-input multiple-output channel is studied. Therein, the nonnegativity constraint of the transmit signal limits the applicability of classical schemes, including precoding. Thus, new ways are required for deriving capacity bounds for this channel. To this end, capacity lower bounds are developed in this paper by deriving the achievable rates of two precodingfree schemes: Channel inversion and QR decomposition. The achievable rate of a DC-offset SVD-based scheme is also derived as a benchmark. Then, capacity upper bounds are derived and compared against the lower bounds. As a result, the capacity at high signal-to-noise ratio (SNR) is characterized for the case where the number of transmit apertures is not larger than the number of receive apertures, and is shown to be achievable by the QR decomposition scheme. This is shown for a channel with average intensity or peak intensity constraints. Under both constraints, the high-SNR capacity is approximated within a small gap. Extensions to a channel with more transmit apertures than receive apertures are discussed, and capacity bounds for this case are derived.

  11. Capacity Bounds and High-SNR Capacity of MIMO Intensity-Modulation Optical Channels

    KAUST Repository

    Chaaban, Anas; Rezki, Zouheir; Alouini, Mohamed-Slim

    2018-01-01

    The capacity of the intensity modulation direct detection multiple-input multiple-output channel is studied. Therein, the nonnegativity constraint of the transmit signal limits the applicability of classical schemes, including precoding. Thus, new ways are required for deriving capacity bounds for this channel. To this end, capacity lower bounds are developed in this paper by deriving the achievable rates of two precodingfree schemes: Channel inversion and QR decomposition. The achievable rate of a DC-offset SVD-based scheme is also derived as a benchmark. Then, capacity upper bounds are derived and compared against the lower bounds. As a result, the capacity at high signal-to-noise ratio (SNR) is characterized for the case where the number of transmit apertures is not larger than the number of receive apertures, and is shown to be achievable by the QR decomposition scheme. This is shown for a channel with average intensity or peak intensity constraints. Under both constraints, the high-SNR capacity is approximated within a small gap. Extensions to a channel with more transmit apertures than receive apertures are discussed, and capacity bounds for this case are derived.

  12. Evaluating Moisture Control of Variable-Capacity Heat Pumps in Mechanically Ventilated, Low-Load Homes in Climate Zone 2A

    Energy Technology Data Exchange (ETDEWEB)

    Eric Martin, Chuck Withers, Janet McIlvaine, Dave Chasar, and David Beal

    2018-03-29

    Low-load homes can present a challenge when selecting appropriate space-conditioning equipment. Conventional, fixed-capacity heating and cooling equipment is often oversized for small homes, causing increased first costs and operating costs. This report evaluates the performance of variable-capacity comfort systems, with a focus on inverter-driven, variable-capacity systems, as well as proposed system enhancements.

  13. A novel high-torque magnetorheological brake with a water cooling method for heat dissipation

    International Nuclear Information System (INIS)

    Wang, D M; Hou, Y F; Tian, Z Z

    2013-01-01

    The extremely severe heating of magnetorheological (MR) brakes restricts their application in high-power situations. This study aims to develop a novel MR brake with a high-torque capacity. To achieve this goal, a water cooling method is adopted to assist in heat dissipation. In the study, a structural model design of the high-torque MR brake is first developed according to the transmission properties of the MR fluid between the rotating plates. Then, the operating principle of the MR brake is illustrated, which is followed by a detailed design of the water channel. Moreover, theoretical analysis, including the transmitted torque, magnetic field and thermal analysis, is performed as well. After this, an experimental prototype of the proposed MR brake is fabricated and assembled. Then the torque transmission and heat dissipation of the prototype are experimentally investigated to evaluate the torque transmission properties and water cooling efficiency. Results indicate that the proposed MR brake is capable of producing a highly controllable brake torque, and the water cooling method can effectively assist in heat dissipation from the MR brake. (paper)

  14. Interplay between the energy gap and heat capacity in S-wave superconductor

    International Nuclear Information System (INIS)

    Gonczarek, R.; Mulak, M.

    1998-01-01

    Starting from the postulated, generalized form of the BCS gap equation, suitable for a wide class of microscopic models, the thermodynamic properties of S-wave superconductors are studied. The precise analytical formulas for the main thermodynamic quantities are given and discussed in the characteristic temperature limits. In particular the inversion of the equations defining the specific heat as a function of Δ(T), i.e. the temperature dependence of the energy gap in S-wave superconductor is presented. It makes possible a reconstruction of the energy gap as a function of temperature from the heat capacity data. As predicted, in the frame of the model, the other thermodynamic quantities from the Δ(T) function seem also to be interesting. (orig.)

  15. Development of a high performances heat pipe (HPHP) for space applications; Developpement d`un caloduc hautes performances (HPHP) pour applications spatiales

    Energy Technology Data Exchange (ETDEWEB)

    Moschetti, B; Voyer, E [Aerospatiale, 06 - Cannes (France)

    1997-12-31

    This paper presents the research program for the development of a prototype of high performances heat pipe (HPHP) intended to be installed on the STENTOR telecommunication satellite. A trade-off study was performed and led to the selection of a reliable and simple concept with axial grooves, ammonia and a minimum heat transport capacity of 500 W.m. A first model with a 17 mm diameter, a 2.8 m length and a mass lower than 500 g/m has been manufactured and tested. First results indicate a 600 W.m heat transport capacity at 20 deg. C (horizontal position) and a 400 W.m capacity with a 5 mm tilt, and allow to validate this concept. (J.S.) 6 refs.

  16. Development of a high performances heat pipe (HPHP) for space applications; Developpement d`un caloduc hautes performances (HPHP) pour applications spatiales

    Energy Technology Data Exchange (ETDEWEB)

    Moschetti, B.; Voyer, E. [Aerospatiale, 06 - Cannes (France)

    1996-12-31

    This paper presents the research program for the development of a prototype of high performances heat pipe (HPHP) intended to be installed on the STENTOR telecommunication satellite. A trade-off study was performed and led to the selection of a reliable and simple concept with axial grooves, ammonia and a minimum heat transport capacity of 500 W.m. A first model with a 17 mm diameter, a 2.8 m length and a mass lower than 500 g/m has been manufactured and tested. First results indicate a 600 W.m heat transport capacity at 20 deg. C (horizontal position) and a 400 W.m capacity with a 5 mm tilt, and allow to validate this concept. (J.S.) 6 refs.

  17. High-Temperature Heat Capacity of Germanates Pr2Ge2O7 and Nd2Ge2O7 within 350-1000 K

    Science.gov (United States)

    Denisova, L. T.; Irtyugo, L. A.; Beletskii, V. V.; Belousova, N. V.; Denisov, V. M.

    2018-03-01

    Pr2Ge2O7 and Nd2Ge2O7 were obtained via solid-phase synthesis from Pr2O3 ( Nd2O3) and GeO2 with multistage firing in air within 1273-1473 K. A temperature effect on molar heat capacity of the oxide compounds was measured with a differential scanning calorimetry. Their thermodynamic properties were calculated from the C P = f( T) dependences.

  18. Key technology studies of GY-20 and GY-40 High-capacity cobalt-60 transport casks

    International Nuclear Information System (INIS)

    Liu Huifang; Zhang Xin

    2012-01-01

    GY-20 and GY-40 high-capacity cobalt-60 transport casks are used to transport cobalt-60 industrial irradiators and cobalt-60 bundles. The radioactive contents have special features of high-activity and high residual heat, so only a few countries such as Canada, England and Russia have design capacity. The key technologies and corresponding solutions were studied for the design and manufacture of the cask taking into account the structural, thermal, mechanics and shield requests. A series of tests prove that the cask structure design, design criteria for lead coating structure and quality control measurements are reasonable and effective, and the cask shield integrity can be ensured for all conditions. The casks have ability to transport high-activity sealed sources safely, and the design of cask satisfies the requirement of design code and standard. It can provide reference for other B type package. (authors)

  19. Effect of water content on specific heat capacity of porcine septum cartilage

    Science.gov (United States)

    Chae, Yongseok; Lavernia, Enrique J.; Wong, Brian J.

    2002-06-01

    The effect of water content on specific heat capacity was examined using temperature modulated Differential Scanning Calorimetry (TMDSC). This research was motivated in part by the development laser cartilage reshaping operations, which use photothermal heating to accelerate stress relaxation and shape change. Deposition of thermal energy leads to mechanical stress relaxation and redistribution of cartilage internal stresses, which may lead to a permanent shape change. The specific heat of cartilage specimens (dia: 3 mm and thickness 1-2 mm) was measured using a heating rate of 2 degree(s)C/min for conventional DSC and 2 degree(s)C/min with an amplitude 0.38-0.45 degree(s)C and a period 60-100 sec for TMDSC. The amount of water in cartilaginous tissue was determined using thermogravimetry analysis (TGA) under ambient conditions. In order to correlate changes in heat flow with alterations in cartilage mechanical behavior, dynamic mechanical temperature analysis (DMTA) was used to estimate the specific transition temperatures where stress relaxation occurs. With decreasing water content, we identified a phase transition that shifted to a higher temperature after 35-45% water content was measured. The phase transition energy increased from 0.12 J/g to 1.68 J/g after a 45% weight loss. This study is a preliminary investigation focused on understanding the mechanism of the stress relaxation of cartilage during heating. The energy requirement of such a transition estimated using TMDSC and temperature range, where cartilage shape changes likely occur, was estimated.

  20. Corrosion of Nickel-Based Alloys in Ultra-High Temperature Heat Transfer Fluid

    Science.gov (United States)

    Wang, Tao; Reddy, Ramana G.

    2017-03-01

    MgCl2-KCl binary system has been proposed to be used as high temperature reactor coolant. Due to its relatively low melting point, good heat capacity and excellent thermal stability, this system can also be used in high operation temperature concentrating solar power generation system as heat transfer fluid (HTF). The corrosion behaviors of nickel based alloys in MgCl2-KCl molten salt system at 1,000 °C were determined based on long-term isothermal dipping test. After 500 h exposure tests under strictly maintained high purity argon gas atmosphere, the weight loss and corrosion rate analysis were conducted. Among all the tested samples, Ni-201 demonstrated the lowest corrosion rate due to the excellent resistance of Ni to high temperature element dissolution. Detailed surface topography and corrosion mechanisms were also determined by using scanning electron microscopy (SEM) equipped with energy dispersive spectrometer (EDS).

  1. Low temperature anomaly of light stimulated magnetization and heat capacity of the 1D diluted magnetic semiconductors

    Science.gov (United States)

    Geffe, Chernet Amente

    2018-03-01

    This article reports magnetization and specific heat capacity anomalies in one dimensional diluted magnetic semiconductors observed at very low temperatures. Based on quantum field theory double time temperature dependent Green function technique is employed to evaluate magnon dispersion and the time correlation function. It is understood that magnon-photon coupling and magnetic impurity concentration controls both, such that near absolute temperature magnetization is nearly zero and abruptly increase to saturation level with decreasing magnon-photon coupling strength. We also found out dropping of magnetic specific heat capacity as a result of increase in magnetic impurity concentration x, perhaps because of inter-band disorder that would suppress the enhancement of density of spin waves.

  2. Low temperature anomaly of light stimulated magnetization and heat capacity of the 1D diluted magnetic semiconductors

    Directory of Open Access Journals (Sweden)

    Chernet Amente Geffe

    2018-03-01

    Full Text Available This article reports magnetization and specific heat capacity anomalies in one dimensional diluted magnetic semiconductors observed at very low temperatures. Based on quantum field theory double time temperature dependent Green function technique is employed to evaluate magnon dispersion and the time correlation function. It is understood that magnon-photon coupling and magnetic impurity concentration controls both, such that near absolute temperature magnetization is nearly zero and abruptly increase to saturation level with decreasing magnon-photon coupling strength. We also found out dropping of magnetic specific heat capacity as a result of increase in magnetic impurity concentration x, perhaps because of inter-band disorder that would suppress the enhancement of density of spin waves.

  3. Dynamic target high pressure control of a VRF system for heating energy savings

    International Nuclear Information System (INIS)

    Yun, Geun Young; Lee, Je Hyeon; Kim, Inhan

    2017-01-01

    Highlights: • We developed the dynamic target high pressure control of a VRF system. • We created the VRF control model using the EnergyPlus runtime language. • Multicalorimeter experimental results indicate that the energy efficiency improved by 21%. • EnergyPlus simulations demonstrate that the annual heating energy consumption was lowered by 22%. - Abstract: Variable refrigerant flow (VRF) systems are widely used because of their ability to provide individualized comfort control with energy-saving potential. This study develops load responsive high pressure control of a VRF system with the aim of reducing the heating energy consumption of a VRF system under part load conditions. The developed control consists of two parts: one part that determines the level of heating load, and the other that assigns a target high pressure based on the level of heating load. In this way, the compressor speed can be accurately matched to heating load, which improves the energy performance of the VRF system. A series of multicalorimeter experiments revealed that the heating capacity of the VRF system varied by 45% by modulating the target high pressure and that its efficiency was enhanced by 21% by changing the high pressure from 30 kgf/cm"2 to 25 kgf/cm"2. To evaluate the annual heating energy performance of the VRF system with the developed control, a custom computer code was developed to implement the developed control using a programming language called EnergyPlus Runtime Language. Simulation outcomes showed that the annual heating energy consumption of a medium-size office building was reduced by 22% when the developed control was applied.

  4. Heat transfer capacity of heat pipes: An application in coalfield wildfire in China

    Science.gov (United States)

    Li, Bei; Deng, Jun; Xiao, Yang; Zhai, Xiaowei; Shu, Chi-Min; Gao, Wei

    2018-06-01

    Coalfield wildfires are serious catastrophes associated with mining activities. Generally, the coal wildfire areas have tremendous heat accumulation regions. Eliminating the internal heat is an effective method for coal wildfire control. In this study, high thermal conductivity component of a heat pipe (HP) was used for enhancing the heat dissipation efficiency and impeding heat accumulation. An experimental system was set up to analyze the thermal resistance network of the coal-HP system. A coal-HP heat removal model was also established for studying the heat transfer performance of HP on the coal pile. The HP exhibited outstanding cooling performance in the initial period, resulting in the highest temperature difference between the coal pile and ambient temperature. However, the effect of the HP on the distribution temperature of coal piles decreased with increasing distance. The largest decline in the coal temperature occurred in a 20-mm radius of the HP; the temperature decreased from 84.3 to 50.9 °C, a decline of 39.6%. The amount of energy transfer by the HP after 80 h was 1.0865, 2.1680, and 3.3649 MJ under the initial heat source temperatures of 100, 150, and 200 °C, respectively. The coal was governed below 80 °C with the HP under the experimental conditions. It revealed that the HP had a substantial effect on thermal removal and inhibited spontaneous coal combustion. In addition, this paper puts forward the technological path of HP to control typical coalfield wildfire. [Figure not available: see fulltext.

  5. Heat capacity and thermal diffusivity of ScD/sub x/ and ErD/sub x/

    International Nuclear Information System (INIS)

    Moss, M.

    1979-04-01

    The heat capacity, C/sub p/ (T = 298-1000 K), and the thermal diffusivity, α(T = 623-773 K), of ScD/sub x/ and ErD/sub x/ (x = 0-1.83) have been measured. C/sub p/ of ScD/sub x/ increases with x for x = 0-1.59 over the entire temperature range, but then declines for x = 1.83. ErD/sub x/ shows a monotonic increase of C/sub p/ with x, and exhibits a sharp positive anomaly at 910 K for x = 1.82. Both materials display an excess heat capacity which is attributed to disorder in the deuterium sublattice. A minimum in α is observed for ScD/sub x/ and ErD/sub x/ at mid-range values of x where disorder is greatest; α for all samples is fairly constant with T in this limited temperature range

  6. 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

  7. High Capacity cylinder roller bearing; High Capacity Zylinderrollenlager. Ein vollrolliges Lager mit Kaefig

    Energy Technology Data Exchange (ETDEWEB)

    Reichert, J.; Baum, J. [SKF, Schweinfurt (Germany)

    2007-07-15

    The high capacity cylinder roller bearing is an example for continuous development of SKF products and does an effective contribution to increase operational safety and offers the possibility to reduce weight and compact design. (GL)

  8. Dynamic Heat Storage and Cooling Capacity of a Concrete Deck with PCM and Thermally Activated Building System

    DEFF Research Database (Denmark)

    Pomianowski, Michal Zbigniew; Heiselberg, Per; Jensen, Rasmus Lund

    2012-01-01

    This paper presents a heat storage and cooling concept that utilizes a phase change material (PCM) and a thermally activated building system (TABS) implemented in a hollow core concrete deck. Numerical calculations of the dynamic heat storage capacity of the hollow core concrete deck element...... in the article highlight the potential of using TABS and PCM in a prefabricated concrete deck element....

  9. Improving Reversible Capacities of High-Surface Lithium Insertion Materials – The Case of Amorphous TiO{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Ganapathy, Swapna [Fundamental Aspects of Materials and Energy, Department of Radiation, Radionucleides and Reactors, Faculty of Applied Sciences, Delft University of Technology, Delft (Netherlands); Basak, Shibabrata [Kavli Institute of Nanoscience, Delft University of Technology, Delft (Netherlands); Lefering, Anton; Rogers, Edith [Fundamental Aspects of Materials and Energy, Department of Radiation, Radionucleides and Reactors, Faculty of Applied Sciences, Delft University of Technology, Delft (Netherlands); Zandbergen, Henny W. [Kavli Institute of Nanoscience, Delft University of Technology, Delft (Netherlands); Wagemaker, Marnix, E-mail: m.wagemaker@tudelft.nl [Fundamental Aspects of Materials and Energy, Department of Radiation, Radionucleides and Reactors, Faculty of Applied Sciences, Delft University of Technology, Delft (Netherlands)

    2014-11-28

    Chemisorbed water and solvent molecules and their reactivity with components from the electrolyte in high-surface nano-structured electrodes remains a contributing factor toward capacity diminishment on cycling in lithium ion batteries due to the limit in maximum annealing temperature. Here, we report a marked improvement in the capacity retention of amorphous TiO{sub 2} by the choice of preparation solvent, control of annealing temperature, and the presence of surface functional groups. Careful heating of the amorphous TiO{sub 2} sample prepared in acetone under vacuum lead to complete removal of all molecular solvent and an improved capacity retention of 220 mAh/g over 50 cycles at a C/10 rate. Amorphous TiO{sub 2} when prepared in ethanol and heated under vacuum showed an even better capacity retention of 240 mAh/g. From Fourier transform infra-red spectroscopy and electron energy loss spectroscopy measurements, the improved capacity is attributed to the complete removal of ethanol and the presence of very small fractions of residual functional groups coordinated to oxygen-deficient surface titanium sites. These displace the more reactive chemisorbed hydroxyl groups, limiting reaction with components from the electrolyte and possibly enhancing the integrity of the solid electrolyte interface. The present research provides a facile strategy to improve the capacity retention of nano-structured electrode materials.

  10. Low-temperature heat capacity of small Nb3Sn polycrystals by ac calorimetry

    International Nuclear Information System (INIS)

    Viswanathan, R.; Johnston, D.C.

    1976-01-01

    It is shown by an ac calorimetry technique that the multiple heat capacity anomalies which occur below the superconducting transition temperature for small polycrystalline Nb 3 Sn samples are intrinsic to these samples. The recent suggestions that shear stresses can account for these results are analyzed for their validity. The dependence of the occurrence of these multiple anomalies upon the thermal history of the samples was investigated

  11. Heat capacity of Sr10(PO4)6Cl2 and Ca10(PO4)6Cl2 by DSC

    International Nuclear Information System (INIS)

    Venkata Krishnan, R.; Jena, Hrudananda; Govindan Kutty, K.V.; Nagarajan, K.

    2008-01-01

    Strontium and calcium chloroapatites were synthesized by wet chemical method, characterized by X-ray diffraction and are found to be phase pure materials. The measured room temperature lattice parameter of Ca 10 (PO 4 ) 6 Cl 2 is a = 9.523 A, c = 6.855 A and for Sr 10 (PO 4 ) 6 Cl 2 is a = 9.876 A, c = 7.188 A. Heat capacity measurements were carried out on Ca 10 (PO 4 ) 6 Cl 2 and Sr 10 (PO 4 ) 6 Cl 2 by DSC in the temperature range 298-800 K. The heat capacity values of Sr 10 (PO 4 ) 6 Cl 2 is higher at all temperatures than Ca 10 (PO 4 ) 6 Cl 2 . Enthalpy and entropy increments were computed. Heat capacity values of Ca 10 (PO 4 ) 6 Cl 2 and Sr 10 (PO 4 ) 6 Cl 2 at 298 K are 758 and 868 J K -1 mol -1 , respectively

  12. Study of CO2 automobile heating system. Paper no. IGEC-1-129

    International Nuclear Information System (INIS)

    Zha, S.; Hafner, A.

    2005-01-01

    Carbon dioxide has become a popular working medium in heat pump water heaters and mobile heat pumping systems due to its environment friendliness and its excellent thermal and transport properties in transcritical cycle. It also looks bright as a complete solution to environmental problem associated with automobile air conditionings. As high efficient mobile engines with less waste heat have been developed, extra heating of the passenger compartment is needed in the cold season. In this investigation, three heating solutions for automobile CO 2 air conditioning systems are provided. They are a bypass CO 2 heating cycle, a conventional CO 2 transcritical heat pump cycle and a high capacity heat pump cycle with economizer. These three solutions are compared with the viewpoints of the efficiency and heating capacity. The test results show that the heating capacity of the bypass heating method is only enough for a small automobile although it has the advantage of simple construction and low investment. The heat pump cycle with economizer applying a special construction reciprocating compressor can obtain a highest capacity even in cold climate. But the investment increase for economizer heat pump cycle includes both the modification of the compressor and the flash tank. And the COPh of economizer heat pump cycle is higher than bypass heating cycle, but lower than conventional heat pump cycle due to the highest capacity operation condition. (author)

  13. Influence of inhomogeneous surface heat capacity on the estimation of radiative response coefficients in a two-zone energy balance model

    Science.gov (United States)

    Park, Jungmin; Choi, Yong-Sang

    2018-04-01

    Observationally constrained values of the global radiative response coefficient are pivotal to assess the reliability of modeled climate feedbacks. A widely used approach is to measure transient global radiative imbalance related to surface temperature changes. However, in this approach, a potential error in the estimate of radiative response coefficients may arise from surface inhomogeneity in the climate system. We examined this issue theoretically using a simple two-zone energy balance model. Here, we dealt with the potential error by subtracting the prescribed radiative response coefficient from those calculated within the two-zone framework. Each zone was characterized by the different magnitude of the radiative response coefficient and the surface heat capacity, and the dynamical heat transport in the atmosphere between the zones was parameterized as a linear function of the temperature difference between the zones. Then, the model system was forced by randomly generated monthly varying forcing mimicking time-varying forcing like an observation. The repeated simulations showed that inhomogeneous surface heat capacity causes considerable miscalculation (down to -1.4 W m-2 K-1 equivalent to 31.3% of the prescribed value) in the global radiative response coefficient. Also, the dynamical heat transport reduced this miscalculation driven by inhomogeneity of surface heat capacity. Therefore, the estimation of radiative response coefficients using the surface temperature-radiation relation is appropriate for homogeneous surface areas least affected by the exterior.

  14. Heat capacity measurement of Ba3SrNb2O9

    International Nuclear Information System (INIS)

    Singh, B.M.; Samui, Pradeep; Agarwal, Renu; Mukerjee, S.K.

    2016-01-01

    Barium, Strontium and Niobium are important fission products in nuclear reactor with reasonable fission yields. During irradiation of oxide fuels, they can combine to form compounds of Ba-Sr-Nb-O system. Therefore, thermodynamic properties of Ba 3 SrNb 2 O 9 are required for modelling fuel behaviour however thermodynamic data of this compound is not available in literature. Ba 3 SrNb 2 O 9 was prepared by solid state route, by mixing stoichiometric amounts of finely grounded SrCO 3 , BaCO 3 and Nb 2 O 5 . Finally mixed powder was pressed into a pellet at 5 ton pressure for 2 minutes in a hydraulic press and the pellet was heated at 1123 K for 60 h in air. The pellet was cooled, finely grounded, re-pelletised and heated at 1473 K for 120 h. The formation of compound was confirmed by X-ray diffraction pattern, collected at room temperature using Cu-K α radiation (λ = 1.54 nm), scanned over the angular range 20-80° (2θ) with steps of 0.02°. Heat capacity of the compound was measured by the classical three-step method, in continuous mode, using LABSYS EVO, in temperature range of 370 and 950 K. No transition was observed in the investigated temperature range

  15. Evaluation of thermal properties of food materials at high pressures using a dual-needle line-heat-source method.

    Science.gov (United States)

    Zhu, S; Ramaswamy, H S; Marcotte, M; Chen, C; Shao, Y; Le Bail, A

    2007-03-01

    Thermal properties of food systems at high pressure (HP) are important in the design and operation of HP processing equipment. Available techniques for thermal property evaluation under HP conditions are still very limited. In this study, a dual-needle line-heat-source (DNL) device was installed in an HP vessel to evaluate thermal conductivity (k), diffusivity (alpha), and volumetric heat capacity (C(pV)) of foods at high pressure. The DNL probe was calibrated using glycerin (0.1 MPa) and 2% (w/w) agar gel (0.1 to 350 MPa) at 5 and 25 degrees C. Calibration results showed a good correlation with the reference data of pure water: R(2)= 0.966 for thermal conductivity and R(2)= 0.837 for diffusivity, and a small standard deviation of relative error (3.18%) for the volumetric heat capacity. Fresh potato and cheddar cheese were used as test samples at 5 degrees C at selected pressure levels (0.1 to 350 MPa). The potato samples gave thermal properties very close to those of pure water, but much higher than those of the cheese. The k and alpha values of both potato and cheese increased with pressure and a 2nd-order polynomial well fitted their pressure dependency. The volumetric heat capacity data did not show a clear pressure-dependency trend. The experimental system worked well for the evaluation of thermal properties at pressures up to 350 MPa.

  16. The heat capacity and entropy of the lithium silicides Li17Si4 and Li16.42Si4 in the temperature range from (2 to 873) K

    International Nuclear Information System (INIS)

    Thomas, Daniel; Zeilinger, Michael; Gruner, Daniel; Hüttl, Regina; Seidel, Jürgen; Wolter, Anja U.B.; Fässler, Thomas F.; Mertens, Florian

    2015-01-01

    Highlights: • High quality experimental heat capacities of the new lithium rich silicides Li 17 Si 4 and Li 16.42 Si 4 are reported. • Two different calorimeters have been used to cover the broad temperature range from (2 to 873) K. • Samples were prepared and characterized (XRD) by the original authors who firstly described these new silicide phases in 2013. • Supply of polynomial heat capacity functions for four temperature intervals. • Calculation of standard entropies and entropies of formation of the lithium silicides. - Abstract: This work presents the heat capacities and standard entropies of the recently described lithium rich silicide phases Li 17 Si 4 and Li 16.42 Si 4 as a function of temperature in the range from (2 to 873) K. The measurements were carried out using two different calorimeters. The heat capacities were determined in the range from T = (2 to 300) K by a relaxation technique using a Physical Properties Measurement System (PPMS) from Quantum Design, and in the range from T = (283 to 873) K by means of a Sensys DSC from Setaram applying the C p -by-step method. The experimental data are given with an accuracy of (1 to 2)% above T = 20 K and the error increases up to 7% below T = 20 K. The results of the measurements at low temperatures permit the calculation of additional thermodynamic parameters such as the standard entropy as well as the temperature coefficients of electronic and lattice contributions to the heat capacity. Additionally, differential scanning calorimetric (DSC) measurements were carried out to verify the phase transition temperatures of the studied lithium silicide phases. The results represent a significant contribution to the data basis for thermodynamic calculations (e.g. CALPHAD) and to the understanding of the phase equilibria in the (Li + Si) system, especially in the lithium rich region

  17. Mössbauer and heat capacity studies of ErZnSn2

    Directory of Open Access Journals (Sweden)

    Łątka Kazimierz

    2017-06-01

    Full Text Available Heat capacity results obtained for the intermetallic compound ErZnSn2 were re-analysed to also consider, apart from the classical Debye model, the anharmonicity of the crystal lattice and the proper set of Einstein modes. The 119mSn Mössbauer technique was applied to derive the hyperfine interaction parameters characteristic of the two inequivalent crystallographic Sn sites in the compound studied. Quadrupole interaction constants, as measured by 119mSn Mössbauer spectroscopy, allowed for estimations of Vzz components of the electric field gradient tensor that exist at both Sn sites in the discussed compound.

  18. High heat flux device of thermonuclear device

    International Nuclear Information System (INIS)

    Tachikawa, Nobuo.

    1994-01-01

    The present invention provides an equipments for high heat flux device (divertor) of a thermonuclear device, which absorbs thermal deformation during operation, has a high installation accuracy, and sufficiently withstands for thermal stresses. Namely, a heat sink member is joined to a structural base. Armour tiles are joined on the heat sink member. Cooling pipes are disposed between the heat sink member and the armour tiles. With such a constitution, the heat sink member using a highly heat conductive material having ductility, such as oxygen free copper, the cooling pipes using a material having excellent high temperature resistance and excellent elongation, such as aluminum-dispersed reinforced copper, and the armour tiles are completely joined on the structural base. Therefore, when thermal deformation tends to cause in the high heat flux device such as a divertor, cooling pipes cause no plastic deformation because of their high temperature resistance, but the heat sink member such as a oxygen free copper causes plastic deformation to absorb thermal deformation. As a result, the high heat flux device such as a divertor causes no deformation. (I.S.)

  19. High temperature heat exchanger application in power engineering and energy-technological processes

    International Nuclear Information System (INIS)

    Shpilrain, E.E.

    1986-01-01

    The possibilities for intensification of various processes in metallurgy and chemical technology, the prospects for enhancing power plant efficiency are often linked with temperature increase of reagents, heat carriers and working fluids. In some cases elevated temperatures give the opportunity to use new and principally different technologies, enhance capacities of power production units and technological apparatuses, improve their economical performance. The variety of problems where high temperature heat exchangers are or can be used are extremely wide. It is therefore impossible to overview all of them in one lecture. Therefore the author tries to consider only some examples which are typical and gives an impression of what kind of problems arise in these cases

  20. The real gas dynamics of the fluids of high specific heat

    International Nuclear Information System (INIS)

    Meier, G.E.A.

    1987-01-01

    The gas dynamics of real fluids show several new effects beyond the gas dynamics of ideal substances. Many of these effects rely on phase changes in the flow fields and can be explained with the help of more complicated thermal and caloric state equations of the real fluids. Complete adiabatic liquefaction and evaporation are possible for those substances whose specific heat exceeds a limit of about twenty gas constants. These fluids consisting of great molecules have so much internal energy storage capacity in their numerous vibrational degrees of freedom that the heat of evaporation can be supplied or also stored in the case of condensation. So liquefaction shock waves, which transform a gas completely or partly into a liquid, are possible. The shock front becomes thereby the surface of a liquid. Partial liquefaction with droplet condensation occurs in weaker shock waves. On the other hand a superheated liquid with high specific heat can be changed into a gas or mixture state in expansion waves or flows. (orig.)

  1. Comparative study of alternative ORC-based combined power systems to exploit high temperature waste heat

    International Nuclear Information System (INIS)

    Zhang, Chengyu; Shu, Gequn; Tian, Hua; Wei, Haiqiao; Liang, Xingyu

    2015-01-01

    Highlights: • Three ORC-based combined systems for ICE exhaust waste heat recovery are studied. • A parametric investigation is conducted under several typical engine conditions. • Performance is evaluated considering six thermodynamic, techno-economic indexes. • DORC distinguishes among other solutions for its highest energy recovery capacity. • TEG–ORC system becomes attractive when exhaust temperature is relatively low. - Abstract: In this paper, various combined power systems which regard organic Rankine cycle (ORC) as bottoming cycle to recover engine’s high temperature exhaust heat are proposed. The topping recovery cycle includes steam Rankine cycle (RC), Brayton cycle (BC) and thermoelectric generator (TEG). Comprehensive evaluations are conducted under five typical engine conditions, ranging from high load to low load, and system performance is assessed in terms of many thermodynamic indexes, such as net output power, thermal efficiency, recovery efficiency and exergy efficiency. Besides that, the irreversibility of each component is also discussed in detail. R123, R245fa and R600a for ORC system are considered to analyze the influence of working fluids. Considering the system techno-economy, the turbine size parameter (SP) and heat transfer capacity (UA) are chosen as key indicators. The results show that compared with the other two investigated approaches, dual-loop ORC (DORC) possesses the highest energy exploitation capacity under the whole operating region, with a 5.57% increase of fuel economy under the rated condition, but its values of SP and UA are large as well. TEG–ORC becomes appealing while under the relatively low load

  2. Bias induced modulation of electrical and thermal conductivity and heat capacity of BN and BN/graphene bilayers

    Energy Technology Data Exchange (ETDEWEB)

    Chegel, Raad, E-mail: Raad.chegel@gmail.com

    2017-04-15

    By using the tight binding approximation and Green function method, the electronic structure, density of state, electrical conductivity, heat capacity of BN and BN/graphene bilayers are investigated. The AA-, AB{sub 1}- and AB{sub 2}- BN/graphene bilayers have small gap unlike to BN bilayers which are wide band gap semiconductors. Unlike to BN bilayer, the energy gap of graphene/BN bilayers increases with external field. The magnitude of the change in the band gap of BN bilayers is much higher than the graphene/BN bilayers. Near absolute zero, the σ(T) is zero for BN bilayers and it increases with temperature until reaches maximum value then decreases. The BN/graphene bilayers have larger electrical conductivity larger than BN bilayers. For both bilayers, the specific heat capacity has a Schottky anomaly.

  3. Small heat-shock proteins and leaf cooling capacity account for the unusual heat tolerance of the central spike leaves in Agave tequilana var. Weber.

    Science.gov (United States)

    Luján, Rosario; Lledías, Fernando; Martínez, Luz María; Barreto, Rita; Cassab, Gladys I; Nieto-Sotelo, Jorge

    2009-12-01

    Agaves are perennial crassulacean acid metabolism (CAM) plants distributed in tropical and subtropical arid environments, features that are attractive for studying the heat-shock response. In agaves, the stress response can be analysed easily during leaf development, as they form a spirally shaped rosette, having the meristem surrounded by folded leaves in the centre (spike) and the unfolded and more mature leaves in the periphery. Here, we report that the spike of Agave tequilana is the most thermotolerant part of the rosette withstanding shocks of up to 55 degrees C. This finding was inconsistent with the patterns of heat-shock protein (Hsp) gene expression, as maximal accumulation of Hsp transcripts was at 44 degrees C in all sectors (spike, inner, middle and outer). However, levels of small HSP (sHSP)-CI and sHSP-CII proteins were conspicuously higher in spike leaves at all temperatures correlating with their thermotolerance. In addition, spike leaves showed a higher stomatal density and abated more efficiently their temperature several degrees below that of air. We propose that the greater capacity for leaf cooling during the day in response to heat stress, and the elevated levels of sHSPs, constitute part of a set of strategies that protect the SAM and folded leaves of A. tequilana from high temperatures.

  4. Enhancing heat capacity of colloidal suspension using nanoscale encapsulated phase-change materials for heat transfer.

    Science.gov (United States)

    Hong, Yan; Ding, Shujiang; Wu, Wei; Hu, Jianjun; Voevodin, Andrey A; Gschwender, Lois; Snyder, Ed; Chow, Louis; Su, Ming

    2010-06-01

    This paper describes a new method to enhance the heat-transfer property of a single-phase liquid by adding encapsulated phase-change nanoparticles (nano-PCMs), which absorb thermal energy during solid-liquid phase changes. Silica-encapsulated indium nanoparticles and polymer-encapsulated paraffin (wax) nanoparticles have been made using colloid method, and suspended into poly-alpha-olefin (PAO) and water for potential high- and low-temperature applications, respectively. The shells prevent leakage and agglomeration of molten phase-change materials, and enhance the dielectric properties of indium nanoparticles. The heat-transfer coefficients of PAO containing indium nanoparticles (30% by mass) and water containing paraffin nanoparticles (10% by mass) are 1.6 and 1.75 times higher than those of corresponding single-phase fluids. The structural integrity of encapsulation allows repeated use of such nanoparticles for many cycles in high heat generating devices.

  5. The effects of heat treatment on the phenolic composition and antioxidant capacity of red wine pomace seasonings.

    Science.gov (United States)

    Del Pino-García, Raquel; González-SanJosé, María L; Rivero-Pérez, María D; García-Lomillo, Javier; Muñiz, Pilar

    2017-04-15

    The impact of thermal processing on the phenolic profile and antioxidant capacity (TAC) of powdered red wine pomace seasonings (RWPSs) obtained from different sources (seedless: Sk-S; whole: W-S; seeds: Sd-S) was assessed. High contents in anthocyanins, flavonol-3-O-glycosides, phenolic acids and flavan-3-ols were found in Sk-S, whereas flavan-3-ols and phenolic acids were the main compounds identified in Sd-S. Reductions in the anthocyanidin and flavonol-3-ol contents mainly determined the effect of heat on the total phenolic contents (Sk-S: -29.4%; W-S: -28.0%; Sd-S: -5.78%), although heating affected positively the phenolic acid and flavonol aglycon contents. Slight TAC decreases were observed in the RWPS-derived extracts (classical Folin-Ciocalteu and ABTS assays). However, higher TAC reductions were detected when the powdered RWPSs were used directly as samples (QUENCHER approach). In conclusion, there is little evidence against submitting RWPSs to thermal processing, as heating affects differently each type of phenolic compound and does not induce very severe TAC decreases in these seasonings. Copyright © 2016 Elsevier Ltd. All rights reserved.

  6. Cooking Appliances Using High-Frequency Heating

    OpenAIRE

    木村, 秀行; Hideyuki, KIMURA; (株)日立製作所機械研究所

    2007-01-01

    We have produced a guide suitable for people with no technical knowledge of cooking appliances that use high-frequency heating. In general, cooking appliances that use an electric heat source are popular since, they are simple to use because the offer easy heat control, are safe because they do not have naked flames, and do not make kitchens dirty because there is no exhaust. In recent years, high-efficiency cooking appliances using high-frequency heating technology have surged in popularity....

  7. High thermal load receiving heat plate

    International Nuclear Information System (INIS)

    Shibutani, Jun-ichi; Shibayama, Kazuhito; Yamamoto, Keiichi; Uchida, Takaho.

    1993-01-01

    The present invention concerns a high thermal load heat receiving plate such as a divertor plate of a thermonuclear device. The high thermal load heat receiving plate of the present invention has a cooling performance capable of suppressing the temperature of an armour tile to less than a threshold value of the material against high thermal loads applied from plasmas. Spiral polygonal pipes are inserted in cooling pipes at a portion receiving high thermal loads in the high temperature load heat receiving plate of the present invention. Both ends of the polygonal pipes are sealed by lids. An area of the flow channel in the cooling pipes is thus reduced. Heat conductivity on the cooling surface of the cooling pipes is increased in the high thermal load heat receiving plate having such a structure. Accordingly, temperature elevation of the armour tile can be suppressed. (I.S.)

  8. Evaluation of an Absorption Heat Pump to Mitigate Plant Capacity Reduction Due to Ambient Temperature Rise for an Air-Cooled Ammonia and Water Cycle: Preprint

    International Nuclear Information System (INIS)

    Bharathan, D.; Nix, G.

    2001-01-01

    Air-cooled geothermal plants suffer substantial decreases in generating capacity at increased ambient temperatures. As the ambient temperature rises by 50 F above a design value of 50 F, at low brine-resource temperatures, the decrease in generating capacity can be more than 50%. This decrease is caused primarily by increased condenser pressure. Using mixed-working fluids has recently drawn considerable attention for use in power cycles. Such cycles are more readily amenable to use of absorption ''heat pumps.'' For a system that uses ammonia and water as the mixed-working fluid, this paper evaluates using an absorption heat pump to reduce condenser backpressure. At high ambient temperatures, part of the turbine exhaust vapor is absorbed into a circulating mixed stream in an absorber in series with the main condenser. This steam is pumped up to a higher pressure and heated to strip the excess vapor, which is recondensed using an additional air-cooled condenser. The operating conditions are chosen to reconstitute this condensate back to the same concentration as drawn from the original system. We analyzed two power plants of nominal 1-megawatt capacity. The design resource temperatures were 250 F and 300 F. Ambient temperature was allowed to rise from a design value of 50 F to 100 F. The analyses indicate that using an absorption heat pump is feasible. For the 300 F resource, an increased brine flow of 30% resulted in a net power increase of 21%. For the 250 F resource, the increase was smaller. However, these results are highly plant- and equipment-specific because evaluations must be carried out at off-design conditions for the condenser. Such studies should be carried out for specific power plants that suffer most from increased ambient temperatures

  9. Heat Transfer in Metal Foam Heat Exchangers at High Temperature

    Science.gov (United States)

    Hafeez, Pakeeza

    Heat transfer though open-cell metal foam is experimentally studied for heat exchanger and heat shield applications at high temperatures (˜750°C). Nickel foam sheets with pore densities of 10 and 40 pores per linear inch (PPI), have been used to make the heat exchangers and heat shields by using thermal spray coating to deposit an Inconel skin on a foam core. Heat transfer measurements were performed on a test rig capable of generating hot gas up to 1000°C. The heat exchangers were tested by exposing their outer surface to combustion gases at a temperature of 550°C and 750°C while being cooled by air flowing through them at room temperature at velocities up to 5 m/s. The temperature rise of the air, the surface temperature of the heat exchangers and the air temperature inside the heat exchanger were measured. The volumetric heat transfer coefficient and Nusselt number were calculated for different velocities. The heat transfer performance of the 40PPI sample brazed with the foil is found to be the most efficient. Pressure drop measurements were also performed for 10 and 40PPI metal foam. Thermographic measurements were done on 40PPI foam heat exchangers using a high temperature infrared camera. A high power electric heater was used to produce hot air at 300°C that passed over the foam heat exchanger while the cooling air was blown through it. Heat shields were made by depositing porous skins on metal foam and it was observed that a small amount of coolant leaking through the pores notably reduces the heat transfer from the hot gases. An analytical model was developed based assuming local thermal non-equilibrium that accounts for the temperature difference between solid and fluid phase. The experimental results are found to be in good agreement with the predicted values of the model.

  10. High voltage and high specific capacity dual intercalating electrode Li-ion batteries

    Science.gov (United States)

    West, William C. (Inventor); Blanco, Mario (Inventor)

    2010-01-01

    The present invention provides high capacity and high voltage Li-ion batteries that have a carbonaceous cathode and a nonaqueous electrolyte solution comprising LiF salt and an anion receptor that binds the fluoride ion. The batteries can comprise dual intercalating electrode Li ion batteries. Methods of the present invention use a cathode and electrode pair, wherein each of the electrodes reversibly intercalate ions provided by a LiF salt to make a high voltage and high specific capacity dual intercalating electrode Li-ion battery. The present methods and systems provide high-capacity batteries particularly useful in powering devices where minimizing battery mass is important.

  11. Suppressed beta relaxations and reduced heat capacity in ultrastable organic glasses prepared by physical vapor deposition

    Science.gov (United States)

    Ediger, Mark

    Glasses play an important role in technology as a result of their macroscopic homogeneity (e.g., the clarity of window glass) and our ability to tune properties through composition changes. A problem with liquid-cooled glasses is that they exhibit marginal kinetic stability and slowly evolve towards lower energy glasses and crystalline states. In contrast, we have shown that physical vapor deposition can prepare glasses with very high kinetic stability. These materials have properties expected for ``million-year-old'' glasses, including high density, low enthalpy, and high mechanical moduli. We have used nanocalorimetry to show that these high stability glasses have lower heat capacities than liquid-cooled glasses for a number of molecular systems. Dielectric relaxation has been used to show that the beta relaxation can be suppressed by nearly a factor of four in vapor-deposited toluene glasses, indicating a very tight packing environment. Consistent with this view, computer simulations of high stability glasses indicate reduced Debye-Waller factors. These high stability materials raise interesting questions about the limiting properties of amorphous packing arrangements.

  12. Ground source heat pump performance in case of high humidity soil and yearly balanced heat transfer

    International Nuclear Information System (INIS)

    Schibuola, Luigi; Tambani, Chiara; Zarrella, Angelo; Scarpa, Massimiliano

    2013-01-01

    Highlights: • GSHPs are simulated in case of humid soil and yearly balanced heat transfer. • Humid soil and yearly balanced heat transfer imply higher compactness of GSHPs. • Resulting GSHPs are compared with other traditional and innovative HVAC systems. • GSHPs score best, especially in case of inverter-driven compressors. - Abstract: Ground source heat pump (GSHP) systems are spreading also in Southern Europe, due to their high energy efficiency both in heating and in cooling mode. Moreover, they are particularly suitable in historical cities because of difficulties in the integration of heating/cooling systems into buildings subjected to historical preservation regulations. In these cases, GSHP systems, especially the ones provided with borehole heat exchangers, are a suitable solution instead of gas boilers, air-cooled chillers or cooling towers. In humid soils, GSHP systems are even more interesting because of their enhanced performance due to higher values of soil thermal conductivity and capacity. In this paper, GSHP systems operating under these boundary conditions are analyzed through a specific case study set in Venice and related to the restoration of an historical building. With this analysis the relevant influences of soil thermal conductivity and yearly balanced heat transfer in the design of the borehole field are shown. In particular, the paper shows the possibility to achieve higher compactness of the borehole field footprint area when yearly balanced heat transfer in the borehole field is expected. Then, the second set of results contained in the paper shows how GSHP systems designed for high humidity soils and yearly balanced heat loads at the ground side, even if characterized by a compact footprint area, may still ensure better performance than other available and more common technologies such as boilers, air-cooled chillers, chillers coupled with cooling towers and heat pumps and chillers coupled with lagoon water. As a consequence

  13. High heat flux facility GLADIS

    International Nuclear Information System (INIS)

    Greuner, H.; Boeswirth, B.; Boscary, J.; McNeely, P.

    2007-01-01

    The new ion beam facility GLADIS started the operation at IPP Garching. The facility is equipped with two individual 1.1 MW power ion sources for testing actively cooled plasma facing components under high heat fluxes. Each ion source generates heat loads between 3 and 55 MW/m 2 with a beam diameter of 70 mm at the target position. These parameters allow effective testing from probes to large components up to 2 m length. The high heat flux allows the target to be installed inclined to the beam and thus increases the heated surface length up to 200 mm for a heat flux of 15 MW/m 2 in the standard operating regime. Thus the facility has the potential capability for testing of full scale ITER divertor targets. Heat load tests on the WENDELSTEIN 7-X pre-series divertor targets have been successfully started. These tests will validate the design and manufacturing for the production of 950 elements

  14. High capacity getter pump for UHV operation

    International Nuclear Information System (INIS)

    Manini, P.; Marino, M.; Belloni, F.; Porro, M.

    1993-01-01

    UHV pumps based on non-evaporable getter coated strips find widespread use in particle accelerators, synchrotron radiation machines and nuclear fusion experimental devices. Depending on the geometric constraints, pressure operation conditions and the foreseen gas loads, optimized getter structures, such as modules and cartridges, can be designed and assembled into a high-efficiency pump. In the present paper, the design and performance of a newly conceived High Capacity Getter Pump (HCGP) based on sintered getter bodies, in the shape of blades instead of strips, is illustrated. The porosity and the specific surface area of the blades and their arrangement in the cartridge have been optimized to significantly increase sorption capacity at a given speed. These pumps are well suited for those applications where a very high gas load is expected during the machine operation. The sintered getter bodies increase surface area and capacity, requiring less frequent reactivation and facilitating greater overall life of the pump. A discussion of the experimental results in terms of sorption speed and capacity for various gases is presented

  15. The Heat Is on: An Inquiry-Based Investigation for Specific Heat

    Science.gov (United States)

    Herrington, Deborah G.

    2011-01-01

    A substantial number of upper-level science students and practicing physical science teachers demonstrate confusion about thermal equilibrium, heat transfer, heat capacity, and specific heat capacity. The traditional method of instruction, which involves learning the related definitions and equations, using equations to solve heat transfer…

  16. Non-Debye heat capacity formula refined and applied to GaP, GaAs, GaSb, InP, InAs, and InSb

    Directory of Open Access Journals (Sweden)

    R. Pässler

    2013-08-01

    Full Text Available Characteristic non-Debye behaviors of low-temperature heat capacities of GaP, GaAs, GaSb, InP, InAs, and InSb, which are manifested above all in form of non-monotonic behaviors (local maxima of the respective Cp(T/T3 curves in the cryogenic region, are described by means of a refined version of a recently proposed low-to-high-temperature interpolation formula of non-Debye type. Least-mean-square fittings of representative Cp(T data sets available for these materials from several sources show excellent agreements, from the liquid-helium region up to room temperature. The results of detailed calculations of the respective material-specific Debye temperature curves, ΘD(T, are represented in graphical form. The strong, non-monotonic variations of ΘD(T values confirm that it is impossible to provide reasonable numerical simulations of measured Cp(T dependences in terms of fixed Debye temperatures. We show that it is possible to describe in good approximation the complete Debye temperature curves, from the cryogenic region up to their definitive disappearance (dropping to 0 in the high temperature region, by a couple of unprecedented algebraic formulas. The task of constructing physically adequate prolongations of the low-temperature Cp(T curves up to melting points was strongly impeded by partly rather large differences (up to an order of 10 J/(K·mol between the high-temperature data sets presented in different research papers and/or data reviews. Physically plausible criteria are invoked, which enabled an a priori rejection of a series of obviously unrealistic high-temperature data sets. Residual uncertainties for GaAs and InAs could be overcome by re-evaluations of former enthalpy data on the basis of a novel set of properly specified four-parameter polynomial expressions applying to large regions, from moderately low temperatures up to melting points. Detailed analytical and numerical descriptions are given for the anharmonicity

  17. Empirical equations for viscosity and specific heat capacity determination of paraffin PCM and fatty acid PCM

    Science.gov (United States)

    Barreneche, C.; Ferrer, G.; Palacios, A.; Solé, A.; Inés Fernández, A.; Cabeza, L. F.

    2017-10-01

    Phase change materials (PCM) used in thermal energy storage (TES) systems have been presented, over recent years, as one of the most effective options in energy storage. Paraffin and fatty acids are some of the most used PCM in TES systems, as they have high phase change enthalpy and in addition they do not present subcooling nor hysteresis and have proper cycling stability. The simulations and design of TES systems require the knowledge of the thermophysical properties of PCM. Thermal conductivity, viscosity, specific heat capacity (Cp) can be experimentally determined, but these are material and time consuming tasks. To avoid or to reduce them, and to have reliable data without the need of experimentation, thermal properties can be calculated by empirical equations. In this study, five different equations are given to calculate the viscosity and specific heat capacity of fatty acid PCM and paraffin PCM. Two of these equations concern, respectively, the empirical calculation of the viscosity and liquid Cp of the whole paraffin PCM family, while the other three equations presented are for the corresponding calculation of viscosity, solid Cp, liquid Cp of the whole fatty acid family of PCM. Therefore, this study summarize the work performed to obtain the main empirical equations to measure the above mentioned properties for whole fatty acid PCM family and whole paraffin PCM family. Moreover, empirical equations have been obtained to calculate these properties for other materials of these PCM groups and these empirical equations can be extrapolated for PCM with higher or lower phase change temperatures within a lower relative error 4%.

  18. Mössbauer spectroscopy, magnetization, magnetic susceptibility, and low temperature heat capacity of α-Na2NpO4

    International Nuclear Information System (INIS)

    Smith, Anna L; Hen, Amir; Magnani, Nicola; Colineau, Eric; Griveau, Jean-Christophe; Raison, Philippe E; Caciuffo, Roberto; Konings, Rudy J M; Sanchez, Jean-Pierre; Cheetham, Anthony K

    2016-01-01

    The physical and chemical properties at low temperatures of hexavalent disodium neptunate α-Na 2 NpO 4 are investigated for the first time in this work using Mössbauer spectroscopy, magnetization, magnetic susceptibility, and heat capacity measurements. The Np(VI) valence state is confirmed by the isomer shift value of the Mössbauer spectra, and the local structural environment around the neptunium cation is related to the fitted quadrupole coupling constant and asymmetry parameters. Moreover, magnetic hyperfine splitting is reported below 12.5 K, which could indicate magnetic ordering at this temperature. This interpretation is further substantiated by the existence of a λ-peak at 12.5 K in the heat capacity curve, which is shifted to lower temperatures with the application of a magnetic field, suggesting antiferromagnetic ordering. However, the absence of any anomaly in the magnetization and magnetic susceptibility data shows that the observed transition is more intricate. In addition, the heat capacity measurements suggest the existence of a Schottky-type anomaly above 15 K associated with a low-lying electronic doublet found about 60 cm −1 above the ground state doublet. The possibility of a quadrupolar transition associated with a ground state pseudoquartet is thereafter discussed. The present results finally bring new insights into the complex magnetic and electronic peculiarities of α-Na 2 NpO 4 . (paper)

  19. The development and application of high-capacity thickening techniques

    International Nuclear Information System (INIS)

    Ji Zhenwan; Song Yuejie

    1995-01-01

    On the basis of sedimentation theory and comparison between the high-capacity and conventional thickening techniques, the authors analyse the ways to increase capacity and to improve technological parameters of thickeners, describes the construction features, development, application, automatic control and test installations of high-capacity thickeners at home and abroad

  20. Research on cooling of ultra high critical heat flux with external flow boiling of water. Challenge to achieve ultra high critical heat flux and improvement in estimation of critical heat flux. JAERI's nuclear research promotion program, H11-004 (Contract research)

    International Nuclear Information System (INIS)

    Monde, Masanori; Mitsutake, Yuichi; Ishida, Kenji; Hino, Ryutaro

    2003-03-01

    An ultra high critical heat flux (CHF) has been challenged with a highly subcooled water jet impinging on a small rectangular heated surface. Major objective of the study is to achieve an ultra high heat flux cooling as large as 100 MW/m 2 and to establish an accurate estimation method of the CHF. The experiments were carried out over the experimental range; a fixed jet diameter of 2 mm, jet velocity of 5 - 35 m/s, degree of subcooling of 80 - 170 K and system pressure of 0.1 - 1.0 MPa. The rectangular heated surface with a thin nickel foil of 0.03 - 0.3 mm in thickness, 5 and 10 mm in length, and 4 mm in width and heated by a direct current. Effects of thickness of heater wall, jet velocity and subcooling on the CHF were experimentally elucidated. The experimental results show that the CHF decreases about 50% as the heater thickness, namely heat capacity of heater decreases. Characteristics of the CHF with heater length of 10 mm are correlated within ±20% by the generalized correlation of subcooled CHF proposed by the authors. However, the CHF with the shorter heater length of 5 mm shows large deviation of -40% especially at lower subcooling and higher velocity. The maximum CHF of 212 MW/m 2 was achieved at the subcooling of 151 K, the jet velocity of 35 m/s and system pressure of 0.5 MPa. The maximum CHF under atmospheric pressure approaches to 48% of the ultimate maximum heat flux given by the assumptions that vapor molecules leave a liquid-vapor interface at the average speed of a Boltzman-Maxwellian gas and any molecules returning to the interface are not permitted. The ratio of the CHF and ultimate maximum heat flux was considerably enhanced from the existing record of 30%. This study can give the feasibility of ultra high heat flux removal facing in a development of components such as a diverter of a fusion reactor. (author)

  1. Quantum thermodynamics from the nonequilibrium dynamics of open systems: Energy, heat capacity, and the third law.

    Science.gov (United States)

    Hsiang, J-T; Chou, C H; Subaşı, Y; Hu, B L

    2018-01-01

    In a series of papers, we intend to take the perspective of open quantum systems and examine from their nonequilibrium dynamics the conditions when the physical quantities, their relations, and the laws of thermodynamics become well defined and viable for quantum many-body systems. We first describe how an open-system nonequilibrium dynamics (ONEq) approach is different from the closed combined system +  environment in a global thermal state (CGTs) setup. Only after the open system equilibrates will it be amenable to conventional thermodynamics descriptions, thus quantum thermodynamics (QTD) comes at the end rather than assumed in the beginning. The linkage between the two comes from the reduced density matrix of ONEq in that stage having the same form as that of the system in the CGTs. We see the open-system approach having the advantage of dealing with nonequilibrium processes as many experiments in the near future will call for. Because it spells out the conditions of QTD's existence, it can also aid us in addressing the basic issues in quantum thermodynamics from first principles in a systematic way. We then study one broad class of open quantum systems where the full nonequilibrium dynamics can be solved exactly, that of the quantum Brownian motion of N strongly coupled harmonic oscillators, interacting strongly with a scalar-field environment. In this paper, we focus on the internal energy, heat capacity, and the third law. We show for this class of physical models, amongst other findings, the extensive property of the internal energy, the positivity of the heat capacity, and the validity of the third law from the perspective of the behavior of the heat capacity toward zero temperature. These conclusions obtained from exact solutions and quantitative analysis clearly disprove claims of negative specific heat in such systems and dispel allegations that in such systems the validity of the third law of thermodynamics relies on quantum entanglement. They are

  2. High-capacity nanocarbon anodes for lithium-ion batteries

    International Nuclear Information System (INIS)

    Zhang, Haitao; Sun, Xianzhong; Zhang, Xiong; Lin, He; Wang, Kai; Ma, Yanwei

    2015-01-01

    Highlights: • The nanocarbon anodes in lithium-ion batteries deliver a high capacity of ∼1100 mA h g −1 . • The nanocarbon anodes exhibit excellent cyclic stability. • A novel structure of carbon materials, hollow carbon nanoboxes, has potential application in lithium-ion batteries. - Abstract: High energy and power density of secondary cells like lithium-ion batteries become much more important in today’s society. However, lithium-ion battery anodes based on graphite material have theoretical capacity of 372 mA h g −1 and low charging-discharging rate. Here, we report that nanocarbons including mesoporous graphene (MPG), carbon tubular nanostructures (CTN), and hollow carbon nanoboxes (HCB) are good candidate for lithium-ion battery anodes. The nanocarbon anodes have high capacity of ∼1100, ∼600, and ∼500 mA h g −1 at 0.1 A g −1 for MPG, CTN, and HCB, respectively. The capacity of 181, 141, and 139 mA h g −1 at 4 A g −1 for MPG, CTN, and HCB anodes is retained. Besides, nanocarbon anodes show high cycling stability during 1000 cycles, indicating formation of a passivating layer—solid electrolyte interphase, which support long-term cycling. Nanocarbons, constructed with graphene layers which fulfill lithiation/delithiation process, high ratio of graphite edge structure, and high surface area which facilitates capacitive behavior, deliver high capacity and improved rate-capability

  3. Effects of caffeine on endurance capacity and psychological state in young females and males exercising in the heat.

    Science.gov (United States)

    Suvi, Silva; Timpmann, Saima; Tamm, Maria; Aedma, Martin; Kreegipuu, Kairi; Ööpik, Vahur

    2017-01-01

    Acute caffeine ingestion is considered effective in improving endurance capacity and psychological state. However, current knowledge is based on the findings of studies that have been conducted on male subjects mainly in temperate environmental conditions, but some physiological and psychological effects of caffeine differ between the sexes. The purpose of this study was to compare the physical performance and psychological effects of caffeine in young women and men exercising in the heat. Thirteen male and 10 female students completed 2 constant-load walks (60% of thermoneutral peak oxygen consumption on a treadmill until volitional exhaustion) in a hot-dry environment (air temperature, 42 °C; relative humidity, 20%) after caffeine (6 mg·kg -1 ) and placebo (wheat flour) ingestion in a double-blind, randomly assigned, crossover manner. Caffeine, compared with placebo, induced greater increases (p exercise in the heat, but it has no impact on thermoregulation or endurance capacity in either gender. Under exercise-heat stress, caffeine reduces ratings of perceived exertion and fatigue in males but not in females.

  4. Battery designs with high capacity anode materials and cathode materials

    Energy Technology Data Exchange (ETDEWEB)

    Masarapu, Charan; Anguchamy, Yogesh Kumar; Han, Yongbong; Deng, Haixia; Kumar, Sujeet; Lopez, Herman A.

    2017-10-03

    Improved high energy capacity designs for lithium ion batteries are described that take advantage of the properties of high specific capacity anode active compositions and high specific capacity cathode active compositions. In particular, specific electrode designs provide for achieving very high energy densities. Furthermore, the complex behavior of the active materials is used advantageously in a radical electrode balancing design that significantly reduced wasted electrode capacity in either electrode when cycling under realistic conditions of moderate to high discharge rates and/or over a reduced depth of discharge.

  5. Combined quantum-mechanical and Calphad approach to description of heat capacity of pure elements below room temperature

    Czech Academy of Sciences Publication Activity Database

    Pavlů, J.; Řehák, Petr; Vřešťál, Jan; Šob, Mojmír

    2015-01-01

    Roč. 51, č. 1 (2015), s. 161-171 ISSN 0364-5916 Institutional support: RVO:68081723 Keywords : Einstein temperature * Heat capacity * Low temperature * Pure elements * SGTE data * Zero Kelvin Subject RIV: BM - Solid Matter Physics ; Magnetism Impact factor: 2.129, year: 2015

  6. Sporulation environment of emetic toxin-producing Bacillus cereus strains determines spore size, heat resistance and germination capacity

    NARCIS (Netherlands)

    Voort, van der M.; Abee, T.

    2013-01-01

    Aim Heat resistance, germination and outgrowth capacity of Bacillus cereus spores in processed foods are major factors in causing the emetic type of gastrointestinal disease. In this study, we aim to identify the impact of different sporulation conditions on spore properties of emetic

  7. High-Capacity Cathode Material with High Voltage for Li-Ion Batteries.

    Science.gov (United States)

    Shi, Ji-Lei; Xiao, Dong-Dong; Ge, Mingyuan; Yu, Xiqian; Chu, Yong; Huang, Xiaojing; Zhang, Xu-Dong; Yin, Ya-Xia; Yang, Xiao-Qing; Guo, Yu-Guo; Gu, Lin; Wan, Li-Jun

    2018-03-01

    Electrochemical energy storage devices with a high energy density are an important technology in modern society, especially for electric vehicles. The most effective approach to improve the energy density of batteries is to search for high-capacity electrode materials. According to the concept of energy quality, a high-voltage battery delivers a highly useful energy, thus providing a new insight to improve energy density. Based on this concept, a novel and successful strategy to increase the energy density and energy quality by increasing the discharge voltage of cathode materials and preserving high capacity is proposed. The proposal is realized in high-capacity Li-rich cathode materials. The average discharge voltage is increased from 3.5 to 3.8 V by increasing the nickel content and applying a simple after-treatment, and the specific energy is improved from 912 to 1033 Wh kg -1 . The current work provides an insightful universal principle for developing, designing, and screening electrode materials for high energy density and energy quality. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  8. Heat-capacity measurement on (Zr1-ySny)Ox from 325 to 905 K

    International Nuclear Information System (INIS)

    Tsuji, Toshihide; Amaya, Masaki; Naito, Keiji

    1993-01-01

    Heat capacities of (Zr 1-y Sn y )O 0.17 and (Zr 1-y Sn y )O 0.28 (y=0-0.07) having α''-ZrO ∼1/6 and α''-ZrO x type crystal structures, respectively, were measured from 325 to 905 K by using an adiabatic scanning calorimeter. Two kinds of heat capacity anomalies were observed for all samples. The anomaly at lower temperatures is attributed to a nonequilibrium phenomenon. Another anomaly at higher temperatures is assigned to an order-disorder rearrangement of oxygen atoms. The transition temperature, transition enthalpy and entropy changes due to the order-disorder transition decreased with increasing tin content, indicating that arrangement of oxygen atoms in the lower temperature phase may be partially disordered by substituting tin for zirconium. The entropy change due to the order-disorder transition for (Zr 1-y Sn y )O 0.17 and (Zr 1-y Sn y )O 0.28 solid solutions is compared with the theoretical value. The solubility limits of (Zr 1-y Sn y )O 0.17 and (Zr 1-y Sn y )O 0.28 were determined from the variation of lattice constants, transition temperature, transition enthalpy and entropy changes against tin content. (orig.)

  9. Effects of temperature-humidity index and chromium supplementation on antioxidant capacity, heat shock protein 72, and cytokine responses of lactating cows.

    Science.gov (United States)

    Zhang, F J; Weng, X G; Wang, J F; Zhou, D; Zhang, W; Zhai, C C; Hou, Y X; Zhu, Y H

    2014-07-01

    Heat stress adversely affects the productivity and immune status of dairy cows. The temperature-humidity index (THI) is commonly used to indicate the degree of heat stress on dairy cattle. We investigated the effects of different THI and Cr supplementation on the antioxidant capacity, the levels of heat shock protein 72 (Hsp72), and cytokine responses of lactating cows. The study used a total of 24 clinically healthy uniparous midlactation Holstein cows, which were randomly divided into 2 groups (n = 12 per group), and was conducted in 3 designated THI periods: low THI period (LTHI; THI = 56.4 ± 2.5), moderate THI period (MTHI; THI = 73.9 ± 1.7), and high THI period (HTHI; THI = 80.3 ± 1.0). The 2 groups of cows were fed corn and corn silage based basal diet supplemented chromium picolinate to provide 3.5 mg of Cr/cow daily (Cr+) or basal diet with no Cr (Cr-). The experiment was a 3 × 2 factorial design. The numbers of leukocytes (P Cows supplemented with Cr had lower (P = 0.009) serum concentrations of cholesterol but greater (P cows supplemented with Cr had greater (P = 0.038) expression of the inhibitor of nuclear factor kappa B α (IκBα) in peripheral blood mononuclear cells (PBMC) compared with those without Cr supplementation in the HTHI, whereas the expression of Hsp72 in PBMC was unaltered. Data indicate that there is a decrease in glucose and increases in BUN and creatinine in the serum of midlactation cows under hot conditions during the summer and that these cows have a lowered oxidative capacity but an elevated antioxidant capacity. In addition, Cr may play an anti-inflammatory role in lactating cows by promoting the release of Hsp72, increasing the production of IL-10, and inhibiting the degradation of IκBα under hot conditions during the summer.

  10. High heat load synchrotron optics

    International Nuclear Information System (INIS)

    Mills, D.M.

    1993-01-01

    Third generation synchrotron radiation sources currently being constructed worldwide will produce x-ray beams of unparalleled power and power density. These high heat fluxes coupled with the stringent dimensional requirements of the x-ray optical components pose a prodigious challenge to designers of x-ray optical elements, specifically x-ray mirrors and crystal monochromators. Although certain established techniques for the cooling of high heat flux components can be directly applied to this problem, the thermal management of high heat load x-ray optical components has several unusual aspects that may ultimately lead to unique solutions. This manuscript attempts to summarize the various approaches currently being applied to this undertaking and to point out the areas of research that require further development

  11. Heat capacity measurements of Sr{sub 2}RuO{sub 4} under uni-axial strain

    Energy Technology Data Exchange (ETDEWEB)

    Li, You-sheng; Mackenzie, Andrew [Max Planck Institute for Chemical Physics of Solids, Dresden (Germany); University of St. Andrews, School of Physics and Astronomy (United Kingdom); Gibbs, Alexandra [Max Planck Institute for Solid State Research, Stuttgart (Germany); Hicks, Clifford [Max Planck Institute for Chemical Physics of Solids, Dresden (Germany); Nicklas, Michael [University of St. Andrews, School of Physics and Astronomy (United Kingdom)

    2016-07-01

    One of the most-discussed possible pairing symmetries of Sr{sub 2}RuO{sub 4} is p{sub x} ± ip{sub y}. By applying strain along left angle 100 right angle -direction, the degeneracy of the p{sub x} and p{sub y} components is lifted, and thus there should be two critical temperatures (T{sub c}). Hicks et al. have observed an increase of T{sub c} of Sr{sub 2}RuO{sub 4} under both compressive and tensile strains, by measuring the susceptibility, which is sensitive only to the first transition. Their results also indicate, indirectly, that any splitting of T{sub c}s might be small. For a direct test of possible splitting, we measure the heat capacity of Sr{sub 2}RuO{sub 4} under strain. To do so, we are developing an approach to measure heat capacity under non-adiabatic conditions. We have observed an increase of T{sub c} under compressive strain. This is the first thermodynamic evidence of the strain-induced increase in T{sub c} of Sr{sub 2}RuO{sub 4}.

  12. ANL ITER high-heat-flux blanket-module heat transfer experiments

    International Nuclear Information System (INIS)

    Kasza, K.E.

    1992-02-01

    An Argonne National Laboratory facility for conducting tests on multilayered slab models of fusion blanket designs is being developed; some of its features are described. This facility will allow testing under prototypic high heat fluxes, high temperatures, thermal gradients, and variable mechanical loadings in a helium gas environment. Steady and transient heat flux tests are possible. Electrical heating by a two-sided, thin stainless steel (SS) plate electrical resistance heater and SS water-cooled cold panels placed symmetrically on both sides of the heater allow achievement of global one-dimensional heat transfer across blanket specimen layers sandwiched between the hot and cold plates. The heat transfer characteristics at interfaces, as well as macroscale and microscale thermomechanical interactions between layers, can be studied in support of the ITER engineering design effort. The engineering design of the test apparatus has shown that it is important to use multidimensional thermomechanical analysis of sandwich-type composites to adequately analyze heat transfer. This fact will also be true for the engineering design of ITER

  13. Optimal usage of low temperature heat sources to supply district heating by heat pumps

    DEFF Research Database (Denmark)

    Pieper, Henrik; Ommen, Torben Schmidt; Markussen, Wiebke Brix

    2017-01-01

    This paper presents a theoretical study on the optimal usage of different low temperature heat sources to supply district heating by heat pumps. The study is based on data for the Copenhagen region. The heat sources were prioritized based on the coefficient of performance calculated for each hour...... and the covered demand of each heat source as well as required peak unit capacity. The results showed that heat pumps using different heat sources yield better performance than a heat pump based on a single one. The performance was influenced by the composition of the different heat sources. It was found that 78......% groundwater, 22% seawater and 0% air resulted in highest COP of 3.33 for the given heat demand. Furthermore, the implementation of rule based short term storage made peak units redundant. The variation in base load capacity showed that heat pumps utilizing the analyzed heat sources could perform very...

  14. Analysis of heat transfer under high heat flux nucleate boiling conditions

    Energy Technology Data Exchange (ETDEWEB)

    Liu, Y.; Dinh, N. [3145 Burlington Laboratories, Raleigh, NC (United States)

    2016-07-15

    Analysis was performed for a heater infrared thermometric imaging temperature data obtained from high heat flux pool boiling and liquid film boiling experiments BETA. With the OpenFOAM solver, heat flux distribution towards the coolant was obtained by solving transient heat conduction of heater substrate given the heater surface temperature data as boundary condition. The so-obtained heat flux data was used to validate them against the state-of-art wall boiling model developed by D. R. Shaver (2015) with the assumption of micro-layer hydrodynamics. Good agreement was found between the model prediction and data for conditions away from the critical heat flux (CHF). However, the data indicate a different heat transfer pattern under CHF, which is not captured by the current model. Experimental data strengthen the notion of burnout caused by the irreversible hot spot due to failure of rewetting. The observation forms a basis for a detailed modeling of micro-layer hydrodynamics under high heat flux.

  15. Analysis of heat transfer under high heat flux nucleate boiling conditions

    International Nuclear Information System (INIS)

    Liu, Y.; Dinh, N.

    2016-01-01

    Analysis was performed for a heater infrared thermometric imaging temperature data obtained from high heat flux pool boiling and liquid film boiling experiments BETA. With the OpenFOAM solver, heat flux distribution towards the coolant was obtained by solving transient heat conduction of heater substrate given the heater surface temperature data as boundary condition. The so-obtained heat flux data was used to validate them against the state-of-art wall boiling model developed by D. R. Shaver (2015) with the assumption of micro-layer hydrodynamics. Good agreement was found between the model prediction and data for conditions away from the critical heat flux (CHF). However, the data indicate a different heat transfer pattern under CHF, which is not captured by the current model. Experimental data strengthen the notion of burnout caused by the irreversible hot spot due to failure of rewetting. The observation forms a basis for a detailed modeling of micro-layer hydrodynamics under high heat flux.

  16. Account of volume heat capacity on interface in numerical solution of the Stephen problem using the strained coordinates method

    International Nuclear Information System (INIS)

    Latynin, V.A.; Reshetov, V.A.; Karaseva, L.N.

    1988-01-01

    Numerical solution of the Stephen problem by the strained coordinate method is presented for an one-dimensional sphere. Differential formulae of heat fluxes from moving interfaces do not take into account volume heat capacities of the front nodes. Calculations, carried out according to these balanced formulae, as well as according to those usually used, have shown that the balanced formulae permit to reduce approximately by an order the number of nodes on the sphere radius, if similar accuracy of heat balance of the whole process of melting or crystallization is observed. 2 refs.; 1 fig

  17. High capacity photonic integrated switching circuits

    NARCIS (Netherlands)

    Albores Mejia, A.

    2011-01-01

    As the demand for high-capacity data transfer keeps increasing in high performance computing and in a broader range of system area networking environments; reconfiguring the strained networks at ever faster speeds with larger volumes of traffic has become a huge challenge. Formidable bottlenecks

  18. High visual working memory capacity in trait social anxiety.

    Science.gov (United States)

    Moriya, Jun; Sugiura, Yoshinori

    2012-01-01

    Working memory capacity is one of the most important cognitive functions influencing individual traits, such as attentional control, fluid intelligence, and also psychopathological traits. Previous research suggests that anxiety is associated with impaired cognitive function, and studies have shown low verbal working memory capacity in individuals with high trait anxiety. However, the relationship between trait anxiety and visual working memory capacity is still unclear. Considering that people allocate visual attention more widely to detect danger under threat, visual working memory capacity might be higher in anxious people. In the present study, we show that visual working memory capacity increases as trait social anxiety increases by using a change detection task. When the demand to inhibit distractors increased, however, high visual working memory capacity diminished in individuals with social anxiety, and instead, impaired filtering of distractors was predicted by trait social anxiety. State anxiety was not correlated with visual working memory capacity. These results indicate that socially anxious people could potentially hold a large amount of information in working memory. However, because of an impaired cognitive function, they could not inhibit goal-irrelevant distractors and their performance decreased under highly demanding conditions.

  19. Ladder Ising spin configurations. Pt. 1. Heat capacity

    International Nuclear Information System (INIS)

    Mejdani, R.; Lambros, A.

    1996-01-01

    We consider a ladder Ising spin model (with two coupled Ising spin chains), characterized by two couplings (interchain and intrachain couplings), to study in detail, in an analytical way, its thermal behaviour and particularly the variation of the specific heat versus temperature, the ratio of interaction constants, and the magnetic field. It is interesting that when the competition between interchain and intrachain interactions is strong the specific heat exhibits a double peak and when the competition is not so strong the specific heat has a single peak. Further, without entering into details, we give, in a numerical way, some similar results for more complicated ladder configurations (with more than two linear Ising chains). The spin-1/2 ladders or systems of spin chains may be realized in nature by vanadyl pyrophosphate ((VO) 2 P 2 O 7 ) or similar materials. All these intermediate systems are today important to gain further insight into the physics of one-dimensional spin chains and two-dimensional high-T c spin systems, both of which have shown interesting and unusual magnetic and superconducting properties. It is plausible that experimental and theoretical studies of ladders may lead to other interesting physical phenomena. (orig.)

  20. Impact of heat-wave at high and low VPD on photosynthetic components of wheat and their recovery

    DEFF Research Database (Denmark)

    Rashid, Muhammad Adil; Andersen, Mathias Neumann; Wollenweber, Bernd

    2018-01-01

    relatively insignificant. The processes involved in CO2-use (i.e. in vivo carboxylation efficiency and Vcmax) presented higher sensitivity than the processes involved in light-use (PSII efficiency, quantum yield and chlorophyll content index). Maximum photosynthetic capacity under high temperature......-impact studies. Higher sensitivity of CO2-use suggested that even moderately high temperature-episodes might limit photosynthetic capacity and hence crop productivity, thus reiterating the need to develop crop cultivars with greater tolerance to high temperatures. Abbreviations Asat, maximum net CO2 assimilation......Indirect effects of high temperature through increased vapor pressure deficit (VPD) are vital but often ignored in climate impact studies. We investigated the direct (via heat) and indirect (via VPD) effects of a post-anthesis applied high temperature episode on biochemical and diffusional...

  1. Heat transfer characteristics and operation limit of pressurized hybrid heat pipe for small modular reactors

    International Nuclear Information System (INIS)

    Kim, Kyung Mo; Bang, In Cheol

    2017-01-01

    Highlights: • Thermal performances and operation limits of hybrid heat pipe were experimentally studied. • Models for predicting the operation limit of the hybrid heat pipe was developed. • Non-condensable gas affected heat transfer characteristics of the hybrid heat pipe. - Abstract: In this paper, a hybrid heat pipe is proposed for use in advanced nuclear power plants as a passive heat transfer device. The hybrid heat pipe combines the functions of a heat pipe and a control rod to simultaneously remove the decay heat generated from the core and shutdown the reactor under accident conditions. Thus, the hybrid heat pipe contains a neutron absorber in the evaporator section, which corresponds to the core of the reactor pressure vessel. The presence of the neutron absorber material leads to differences in the heated diameter and hydraulic diameter of the heat pipe. The cross-sectional areas of the vapor paths through the evaporator, adiabatic, and condenser sections are also different. The hybrid heat pipe must operate in a high-temperature, high-pressure environment to remove the decay heat. In other words, the operating pressure must be higher than those of the commercially available thermosyphons. Hence, the thermal performances, including operation limit of the hybrid heat pipe, were experimentally studied in the operating pressure range of 0.2–20 bar. The operating pressure of the hybrid heat pipe was controlled by charging the non-condensable gas which is unused method to achieve the high saturation pressure in conventional thermosyphons. The effect of operating pressure on evaporation heat transfer was negligible, while condensation heat transfer was affected by the amount of non-condensable gas in the test section. The operation limit of the hybrid heat pipe increased with the operating pressure. Maximum heat removal capacity of the hybrid heat pipe was up to 6 kW which is meaningful value as a passive decay heat removal device in the nuclear power

  2. Use of additives to improve the capacity of bituminous mixtures to be heated by means of microwaves

    International Nuclear Information System (INIS)

    Gallego, J.; Val, M.A. del; Contreras, V.; Páez, A.

    2017-01-01

    This study examines the potential of adding electric arc furnace slag to bituminous mixtures to be heated by microwaves. The susceptibility of bituminous mixtures to microwave energy is limited and so, in order to improve the energy performance of the heating process, it is necessary to incorporate additives or components to the mixture so as to improve the capacity for microwave heating. The article presents the results of adding various components, (steel wool, scrap tire wire, silicon carbide, iron filings) and an alternative aggregate: electric arc furnace slag. According to the results obtained in the laboratory, slag addition of at least 5% by weight of the bituminous mixture represents the best option for both technical and economic reasons. The results may promote the valorization of this steel industry residue in bituminous mixtures by improving microwave heating response. [es

  3. High temperature industrial heat pumps

    Energy Technology Data Exchange (ETDEWEB)

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

    1990-01-01

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

  4. High capacity anode materials for lithium ion batteries

    Science.gov (United States)

    Lopez, Herman A.; Anguchamy, Yogesh Kumar; Deng, Haixia; Han, Yongbon; Masarapu, Charan; Venkatachalam, Subramanian; Kumar, Suject

    2015-11-19

    High capacity silicon based anode active materials are described for lithium ion batteries. These materials are shown to be effective in combination with high capacity lithium rich cathode active materials. Supplemental lithium is shown to improve the cycling performance and reduce irreversible capacity loss for at least certain silicon based active materials. In particular silicon based active materials can be formed in composites with electrically conductive coatings, such as pyrolytic carbon coatings or metal coatings, and composites can also be formed with other electrically conductive carbon components, such as carbon nanofibers and carbon nanoparticles. Additional alloys with silicon are explored.

  5. Mechanics of high-capacity electrodes in lithium-ion batteries

    International Nuclear Information System (INIS)

    Zhu, Ting

    2016-01-01

    Rechargeable batteries, such as lithium-ion batteries, play an important role in the emerging sustainable energy landscape. Mechanical degradation and resulting capacity fade in high-capacity electrode materials critically hinder their use in high-performance lithium-ion batteries. This paper presents an overview of recent advances in understanding the electrochemically-induced mechanical behavior of the electrode materials in lithium-ion batteries. Particular emphasis is placed on stress generation and facture in high-capacity anode materials such as silicon. Finally, we identify several important unresolved issues for future research. (topical review)

  6. EXPERIENCE OF UTILIZATION OF CAPACITY BANKS AND SCHEMES OF FREQUENCY REGULATION IN MUNICIPAL CENTRALIZED HEATING SYSTEM OF CHISINAU

    Directory of Open Access Journals (Sweden)

    CHERNEI M

    2013-04-01

    Full Text Available The current paper provides a brief summary of the district heating system of the municipality Chisinau, including heat power sources, heat distribution network, production and consumption development over the past two decades and other data. Also, the priority investment projects realized by JSC "Termocom" are being presented. The company had implemented an automated monitoring system for the heat power production, transportation and distribution. For many years, the company used bellows pipes with polyurethane insulation, ball valves and plate heat exchangers. 14 out of 21 district heating boiler stations were upgraded 10 were completely automated having as a result no further need in full-time duty personnel there. The experience gained in the implementation of capacity banks and frequency inverters, summarizing the benefits and achieved results, is also presented in the current paper. It is to be underlined that in 2011 the company achieved decrease in electricity consumption by about 30% in comparison with 2005.

  7. Critical behavior of binary mixture of {(1 − x) C6H5CN + x CH3(CH2)9CH3}: Measurements of coexistence curves, turbidity, and heat capacity

    International Nuclear Information System (INIS)

    Yin Tianxiang; Lei Yuntao; Mao Chunfeng; Chen Zhiyun; An Xueqin; Shen Weiguo

    2012-01-01

    Highlights: ► Coexistence curve, isobaric heat capacity and turbidity measurements have been reported. ► Asymmetry of the coexistence curves has been analyzed by the complete scaling theory. ► Heat capacity has been shown to be important in describing the asymmetric criticality. ► Universal amplitude ratios have been tested. - Abstract: (Liquid + liquid) coexistence curve, turbidity, and isobaric heat capacity per unit volume for the critical solution of {benzonitrile + n-undecane} have been measured. The critical exponents β, ν, γ, and α have been deduced, which were found to be consistent with the theoretic predictions. Meanwhile, the experimental data have also been analyzed to obtain the system-dependent critical amplitudes B, ξ 0 , χ 0 , A ± , and D corresponding to the difference of the general density variable of two coexisting phases Δρ, the correlation length ξ, the osmotic compressibility χ, the isobaric heat capacity per unit volume C p V −1 , and the first term of correction-to-scaling for the isobaric heat capacity per unit volume, which were used to test some universal ratios. It was found that the coexistence curve may be well described by the crossover model proposed by Gutkowski et al. The critical-fluctuation induced contribution to the background heat capacity B cr was obtained and used to analyze the asymmetric behavior of the diameter of the coexistence curve. The result indicated that the asymmetry of the coexistence curve can be well described by the complete scaling theory proposed by Anisimov et al., and the heat capacity does make a significant contribution to this asymmetric behavior.

  8. Isobaric specific heat capacity of water and aqueous cesium chloride solutions for temperatures between 298 K and 370 K at p = 0.1 MPa

    International Nuclear Information System (INIS)

    Lourenco, M.J.V.; Santos, F.J.V.; Ramires, M.L.V.; Nieto de Castro, C.A.

    2006-01-01

    There has been some controversy regarding the uncertainty of measurements of thermal properties using differential scanning calorimeters, namely heat capacity of liquids. A differential scanning calorimeter calibrated in enthalpy and temperature was used to measure the isobaric specific heat capacity of water and aqueous solutions of cesium chloride, in the temperature range 298 K to 370 K, for molalities up 3.2 mol . kg -1 , at p = 0.1 MPa, with an estimated uncertainty (ISO definition) better than 1.1%, at a 95% confidence level. The measurements are completely traceable to SI units of energy and temperature. The results obtained were correlated as a function of temperature and molality and compared with other authors, obtained by different methods and permit to conclude that a DSC calibrated by Joule effect is capable of very accurate measurements of the isobaric heat capacity of liquids, traceable to SI units of measurement

  9. Heat capacity measurements on Ybx Gd2–x Zr2 O7 (x= 0, 1, 2 ...

    Indian Academy of Sciences (India)

    Home; Journals; Bulletin of Materials Science; Volume 32; Issue 6. Heat capacity measurements on YbGd2–Zr2O7 ( = 0, 1, 2) ceramics by differential scanning calorimetry. Zhan-Guo Liu Jia-Hu Ouyang Yu Zhou. Ceramics and Glasses Volume 32 Issue 6 December 2009 pp 603-606 ...

  10. District heating grid of the Daqing Nuclear Heating Plant

    Energy Technology Data Exchange (ETDEWEB)

    Changwen, Ma [Institute of Nuclear Energy and Technology, Tsingua Univ., Beijing (China)

    1997-09-01

    The Daqing Nuclear Heating Plant is the first commercial heating plant to be built in China. The plant is planned to be used as the main heat resource of one residential quarter of Daqing city. The main parameters of the heating plant are summarized in the paper. The load curve shows that the capacity of the NHP is about 69% of total capacity of the grid. The 12 existing boilers can be used as reserve and peak load heat resources. Two patterns of load following have have been considered and tested on the 5MW Test Heating Reactor. Experiment shows load of heat grid is changed slowly, so automatic load following is not necessary. (author). 9 figs, 1 tab.

  11. Super high field ohmically heated tokamak operation

    International Nuclear Information System (INIS)

    Cohn, D.R.; Bromberg, L.; Leclaire, R.J.; Potok, R.E.; Jassby, D.L.

    1986-01-01

    The authors discuss a super high field mode of tokamak operation that uses ohmic heating or near ohmic heating to ignition. The super high field mode of operation uses very high values of Β/sup 2/α, where Β is the magnetic field and a is the minor radius (Β/sup 2/α > 100 T/sup 2/m). We analyze copper magnet devices with major radii from 1.7 to 3.0 meters. Minimizing or eliminating the need for auxiliary heating has the potential advantages of reducing uncertainty in extrapolating the energy confinement time of current tokamak devices, and reducing engineering problems associated with large auxiliary heating requirements. It may be possible to heat relatively short pulse, inertially cooled tokamaks to ignition with ohmic power alone. However, there may be advantages in using a very small amount of auxiliary power (less than the ohmic heating power) to boost the ohmic heating and provide a faster start-up, expecially in relatively compact devices

  12. Heat capacity and magnetic properties of fluoride CsFe{sup 2+}Fe{sup 3+}F{sub 6} with defect pyrochlore structure

    Energy Technology Data Exchange (ETDEWEB)

    Gorev, M.V., E-mail: gorev@iph.krasn.ru [Kirensky Institute of Physics, Russian Academy of Sciences, Siberian Branch, 660036 Krasnoyarsk (Russian Federation); Institute of Engineering Physics and Radio Electronics, Siberian State University, 660074 Krasnoyarsk (Russian Federation); Flerov, I.N. [Kirensky Institute of Physics, Russian Academy of Sciences, Siberian Branch, 660036 Krasnoyarsk (Russian Federation); Institute of Engineering Physics and Radio Electronics, Siberian State University, 660074 Krasnoyarsk (Russian Federation); Tressaud, A. [Institut de Chimie de la Matière Condensée, ICMCB-CNRS, Université Bordeaux, 33608 Pessac Cedex (France); Bogdanov, E.V. [Kirensky Institute of Physics, Russian Academy of Sciences, Siberian Branch, 660036 Krasnoyarsk (Russian Federation); Astafijev Krasnoyarsk State Pedagogical University, 660049 Krasnoyarsk (Russian Federation); Kartashev, A.V. [Kirensky Institute of Physics, Russian Academy of Sciences, Siberian Branch, 660036 Krasnoyarsk (Russian Federation); Krasnoyarsk State Agrarian University, 660049 Krasnoyarsk (Russian Federation); Bayukov, O.A. [Kirensky Institute of Physics, Russian Academy of Sciences, Siberian Branch, 660036 Krasnoyarsk (Russian Federation); Eremin, E.V. [Kirensky Institute of Physics, Russian Academy of Sciences, Siberian Branch, 660036 Krasnoyarsk (Russian Federation); Institute of Engineering Physics and Radio Electronics, Siberian State University, 660074 Krasnoyarsk (Russian Federation); Krylov, A.S. [Kirensky Institute of Physics, Russian Academy of Sciences, Siberian Branch, 660036 Krasnoyarsk (Russian Federation)

    2016-05-15

    Heat capacity, Mössbauer and Raman spectra as well as magnetic properties of fluoride CsFe{sub 2}F{sub 6} with defect pyrochlore structure were studied. In addition to recently found above room temperature three successive structural transformations Pnma-Imma-I4{sub 1}amd-Fd-3m, phase transition of antiferromagnetic nature with the 13.7 K Neel temperature and a broad heat capacity anomaly with a maximum at about 30 K were observed. The room temperature symmetry Pnma is unchanged at least down to 7 K. Simple model of indirect bond used to estimate the exchange interactions and to propose a magnetic structure model. - Graphical abstract: The ordered arrangement of Fe{sup 2+} and Fe{sup 3+} ions in high-spin states as well as antiferromagnetic phase transition followed by significant magnetic frustrations were found in pyrocholore-related CsFe{sup 2+}Fe{sup 3+}F{sub 6}. A magnetic structure was proposed using a simple model of indirect bonds. - Highlights: • The Pnma structure in pyrocholore CsFe{sub 2}F{sub 6} is stable down to helium temperature. • Mössbauer spectra confirmed the ordering of Fe{sup 2+} and Fe{sup 3+} ions. • Antiferromagnetic transformation and significant magnetic frustrations are found. • Experimental magnetic entropy agrees with entropy for Fe ions in high-spin state. • Superexchange interactions were calculated and a magnetic structure was proposed.

  13. Design manual. [High temperature heat pump for heat recovery system

    Energy Technology Data Exchange (ETDEWEB)

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

    1980-01-01

    The design and performance of a waste heat recovery system which utilizes a high temperature heat pump and which is intended for use in those industries incorporating indirect drying processes are described. It is estimated that use of this heat recovery system in the paper, pulp, and textile industries in the US could save 3.9 x 10/sup 14/ Btu/yr. Information is included on over all and component design for the heat pump system, comparison of prime movers for powering the compressor, control equipment, and system economics. (LCL)

  14. High-heat-flux testing of helium-cooled heat exchangers for fusion applications

    International Nuclear Information System (INIS)

    Youchison, D.L.; Izenson, M.G.; Baxi, C.B.; Rosenfeld, J.H.

    1996-01-01

    High-heat-flux experiments on three types of helium-cooled divertor mock-ups were performed on the 30-kW electron beam test system and its associated helium flow loop at Sandia National Laboratories. A dispersion-strengthened copper alloy (DSCu) was used in the manufacture of all the mock-ups. The first heat exchanger provides for enhanced heat transfer at relatively low flow rates and much reduced pumping requirements. The Creare sample was tested to a maximum absorbed heat flux of 5.8 MW/m 2 . The second used low pressure drops and high mass flow rates to achieve good heat removal. The GA specimen was tested to a maximum absorbed heat flux of 9 MW/m 2 while maintaining a surface temperature below 400 degree C. A second experiment resulted in a maximum absorbed heat flux of 34 MW/m 2 and surface temperatures near 533 degree C. The third specimen was a DSCu, axial flow, helium-cooled divertor mock-up filled with a porous metal wick which effectively increases the available heat transfer area. Low mass flow and high pressure drop operation at 4.0 MPa were characteristic of this divertor module. It survived a maximum absorbed heat flux of 16 MW/m 2 and reached a surface temperature of 740 degree C. Thermacore also manufactured a follow-on, dual channel porous metal-type heat exchanger, which survived a maximum absorbed heat flux of 14 MW/m 2 and reached a maximum surface temperature of 690 degree C. 11refs., 20 figs., 3 tabs

  15. Seismic capacity evaluation of a group of vertical U-tube heat exchanger with support frames for seismic PSA

    International Nuclear Information System (INIS)

    Watanabe, Yuichi; Muramatsu, Ken; Oikawa, Tetsukuni

    2005-01-01

    This paper presents an evaluation of seismic capacity of a group of vertical U-tube type heat exchangers (HXs) with support frames to contribute to refinement of seismic capacity data for seismic Probabilistic Safety Assessment (PSA) in Japan. According to usual practice of seismic PSAs, capacity of component is represented as a log-normally distributed random variable defined by a median and logarithmic standard deviations (LSDs), which represent inherent randomness about the median, β r , and uncertainty in the median due to lack of knowledge, β u . Using design specifications of four HXs for residual heat removal systems of 1100 MWe BWRs, the authors evaluated a generic capacity of HXs with a LSD for uncertainty due to lack of knowledge to take into account design variability. The median capacity was evaluated by the use of a time history response analysis with a detailed model for a selected representative HX, which was extended from a model used in seismic design. The LSD for uncertainty due to lack of knowledge was evaluated with consideration of the variabilities in three influential design parameters, i.e., diameter of anchor bolt, weight of HX and position of center of gravity of HX with the detailed model and a simplified static model. The LSD for uncertainty due to randomness was determined from the variability in material property. The dominant failure mode of HXs was identified as the failure of anchor bolts of lugs mainly due to shearing stress. The capacity expressed in terms of zero period acceleration on the foundation of HX was evaluated to be 4180 Gal (4.3 g) for median, LSD for uncertainty due to randomness was 0.11 and LSD due to lack of knowledge was 0.21-0.53 depending on combination of the variabilities in design parameters to be considered

  16. High performance passive solar heating system with heat pipe energy transfer and latent heat storage

    NARCIS (Netherlands)

    Dijk, van H.A.L.; Galen, van E; Hensen, J.L.M.; Wit, de M.H.

    1983-01-01

    Preliminar results are reported from a current project on the development of a high performance passive solar heating system. Two special components are introduced: a. A heat pipe as a thermal diode tube for the efficient transfer of collected solar heat from the absorber plate to behind an

  17. Flue gas moisture capacity calculation at the outlet of the condensation heat recovery unit

    Directory of Open Access Journals (Sweden)

    Galashov Nikolay

    2017-01-01

    Full Text Available As a result, study equation has been obtained which determine the flue gas moisture capacity at the outlet of the condensation heat recovery unit with an error of less than 1%. It possible to at the temperature of the flue gas below the dew point and the known air-fuel ratio efficient. The equation can be used to calculate plants operating on products of gas combustion without Use of tables and programs for calculating the water-vapor saturation pressure.

  18. Low-temperature heat capacity and standard molar enthalpy of formation of 9-fluorenemethanol (C14H12O)

    International Nuclear Information System (INIS)

    Di, You-Ying; Tan, Zhi-Cheng.; Sun, Xiao-Hong; Wang, Mei-Han; Xu, Fen; Liu, Yuan-Fa; Sun, Li-Xian; Zhang, Hong-Tao

    2004-01-01

    Low-temperature heat capacities of the 9-fluorenemethanol (C 14 H 12 O) have been precisely measured with a small sample automatic adiabatic calorimeter over the temperature range between T=78 K and T=390 K. The solid-liquid phase transition of the compound has been observed to be T fus =(376.567±0.012) K from the heat-capacity measurements. The molar enthalpy and entropy of the melting of the substance were determined to be Δ fus H m =(26.273±0.013) kJ · mol -1 and Δ fus S m =(69.770±0.035) J · K -1 · mol -1 . The experimental values of molar heat capacities in solid and liquid regions have been fitted to two polynomial equations by the least squares method. The constant-volume energy and standard molar enthalpy of combustion of the compound have been determined, Δ c U(C 14 H 12 O, s)=-(7125.56 ± 4.62) kJ · mol -1 and Δ c H m compfn (C 14 H 12 O, s)=-(7131.76 ± 4.62) kJ · mol -1 , by means of a homemade precision oxygen-bomb combustion calorimeter at T=(298.15±0.001) K. The standard molar enthalpy of formation of the compound has been derived, Δ f H m compfn (C 14 H 12 O,s)=-(92.36 ± 0.97) kJ · mol -1 , from the standard molar enthalpy of combustion of the compound in combination with other auxiliary thermodynamic quantities through a Hess thermochemical cycle

  19. Age-related oxidative stress and antioxidant capacity in heat-stressed broilers.

    Science.gov (United States)

    Del Vesco, A P; Khatlab, A S; Goes, E S R; Utsunomiya, K S; Vieira, J S; Oliveira Neto, A R; Gasparino, E

    2017-10-01

    We aimed to evaluate the effects of acute heat stress (HS) and age on the redox state in broilers aged 21 and 42 days. We evaluated the expression of genes related to antioxidant capacity, the production of hydrogen peroxide (H2O2), and the activity of antioxidant enzymes in the liver, as well as oxidative stress markers in the liver and plasma. The experiment had a completely randomized factorial design with two thermal environments (thermoneutral and HS, 38°C for 24 h) and two ages (21 and 42 days). Twenty-one-day-old animals exposed to HS showed the highest thioredoxin reductase 1 (TrxR1) (PAge influenced the expression of the thioredoxin (Trx) (P=0.0090), superoxide dismutase (SOD) (P=0.0194), glutathione reductase (GSR) (Page and environment on the liver content of Glutathione (GSH) (Page had higher plasma creatinine content (0.05 v. 0.01 mg/dl) and higher aspartate aminotransferase activity (546.50 v. 230.67 U/l) than chickens at 21 days of age. Our results suggest that under HS conditions, in which there is higher H2O2 production, 21-day-old broilers have greater antioxidant capacity than 42-day-old animals.

  20. A Study on Electric Vehicle Heat Pump Systems in Cold Climates

    Directory of Open Access Journals (Sweden)

    Ziqi Zhang

    2016-10-01

    Full Text Available Electric vehicle heat pumps are drawing more and more attention due to their energy-saving and high efficiency designs. Some problems remain, however, in the usage of the heat pumps in electric vehicles, such as a drainage problem regarding the external heat exchangers while in heat pump mode, and the decrease in heating performance when operated in a cold climate. In this article, an R134a economized vapor injection (EVI heat pump system was built and tested. The drainage problem common amongst external heat exchangers was solved by an optimized 5 mm diameter tube-and-fin heat exchanger, which can meet both the needs of a condenser and evaporator based on simulation and test results. The EVI system was also tested under several ambient temperatures. It was found that the EVI was a benefit to the system heating capacity. Under a −20 °C ambient temperature, an average improvement of 57.7% in heating capacity was achieved with EVI and the maximum capacity was 2097 W, with a coefficient of performance (COP of 1.25. The influences of injection pressure and economizer capacity are also discussed in this article.

  1. High temperature alloys and ceramic heat exchanger

    International Nuclear Information System (INIS)

    Okamoto, Masaharu

    1984-04-01

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

  2. Graded Reflectivity Mirror for the Solid State Heat Capacity Laser Final Report CRADA No. TC-2085-04

    Energy Technology Data Exchange (ETDEWEB)

    Yamamoto, R. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Davis, J. A. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2017-09-27

    This was a collaborative effort between The Regents of the University of California, Lawrence Livermore National Laboratory (LLNL) and the Boeing Company, to develop a Graded Reflectivity Mirror (GRM) to achieve improved near field fill and higher brightness in the far field output of LLNL’s Solid State Heat Capacity Laser (SSHCL).

  3. A study of heat capacity temperature limit of BWR

    International Nuclear Information System (INIS)

    Wang, Shih-Jen; Chen, Jyh-Jun; Chien, Chun-Sheng; Teng, Jyh-Tong

    2012-01-01

    Highlights: ► The purpose of this study is to verify the HCTL. ► MAAP4 was used as code to generate a realistic and convenient HCTL. ► The current HCTL curve causes confusing in reading data. ► The revised HCTL curves developed in this study. ► Users can obtain important parameters from the revised HCTL without confusion and interpolation. - Abstract: Heat capacity temperature limit (HCTL) is an important parameter for operation of BWR. Current version of the HCTL was derived, based on simple model of computation aids (CA) of BWR owners’ group (BWROG). However, some parts of the current HCTL are confusing to the users in reading data. The purpose of this study is to verify the HCTL by applying the MAAP4 code to the field of emergency operating procedure (EOP). The trends of HCTL generated by MAAP4 code are consistent with those obtained from CA. A series of revised HCTL evaluated at various times after scram are provided and the confusing part is eliminated.

  4. Heat capacity and solid solubility of iron in scandium

    International Nuclear Information System (INIS)

    Tsang, T.-W.E.

    1981-01-01

    The maximum solid solubility of iron in scandium was determined to be between 50 and 85 at.ppm in the as-cast condition. As the concentration of iron increases, it segregates along the grain boundary, as is evident from optical metallography and electron microprobe examinations. Annealing also causes the iron dissolved in scandium to separate out and cluster along the grain boundary. Heat capacity measurements show an anomaly in the C/T versus T 2 plots for iron concentrations of 19 at.ppm or greater. For iron dissolved in solid scandium the excess entropy due to the iron impurity is in agreement with the theoretical prediction of ck ln(2S + 1) for an impurity-conduction electron (Kondo) interaction, but is 4 - 8 times larger than the theoretical prediction when iron segregates along the grain boundary. Furthermore, our results suggest that most of the previously reported low temperature physical properties of scandium are probably in error because of either iron impurity-conduction electron interactions or Fe-Fe interactions in the precipitated second-phase Sc-Fe compound. (Auth.)

  5. A study of heat capacity temperature limit of BWR

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Shih-Jen, E-mail: sjenwang@iner.gov.tw [Institute of Nuclear Energy Research (INER), 1000, Wunhua Rd., Jiaan Village, Longtan Township, Taoyuan County 32546, Taiwan (China); Chen, Jyh-Jun [Department of Mechanical Engineering, Chung Yuan Christian University, 200, Chung Pei Rd., Chung Li City, Taoyuan County 32023, Taiwan (China); Chien, Chun-Sheng [Institute of Nuclear Energy Research (INER), 1000, Wunhua Rd., Jiaan Village, Longtan Township, Taoyuan County 32546, Taiwan (China); Teng, Jyh-Tong [Department of Mechanical Engineering, Chung Yuan Christian University, 200, Chung Pei Rd., Chung Li City, Taoyuan County 32023, Taiwan (China)

    2012-02-15

    Highlights: Black-Right-Pointing-Pointer The purpose of this study is to verify the HCTL. Black-Right-Pointing-Pointer MAAP4 was used as code to generate a realistic and convenient HCTL. Black-Right-Pointing-Pointer The current HCTL curve causes confusing in reading data. Black-Right-Pointing-Pointer The revised HCTL curves developed in this study. Black-Right-Pointing-Pointer Users can obtain important parameters from the revised HCTL without confusion and interpolation. - Abstract: Heat capacity temperature limit (HCTL) is an important parameter for operation of BWR. Current version of the HCTL was derived, based on simple model of computation aids (CA) of BWR owners' group (BWROG). However, some parts of the current HCTL are confusing to the users in reading data. The purpose of this study is to verify the HCTL by applying the MAAP4 code to the field of emergency operating procedure (EOP). The trends of HCTL generated by MAAP4 code are consistent with those obtained from CA. A series of revised HCTL evaluated at various times after scram are provided and the confusing part is eliminated.

  6. Cold Climate Heat Pumps Using Tandem Compressors

    Energy Technology Data Exchange (ETDEWEB)

    Shen, Bo [ORNL; Abdelaziz, Omar [ORNL; Rice, C Keith [ORNL; Baxter, Van D [ORNL

    2016-01-01

    In cold climate zones, e.g. ASHRAE climate regions IV and V, conventional electric air-source heat pumps (ASHP) do not work well, due to high compressor discharge temperatures, large pressure ratios and inadequate heating capacities at low ambient temperatures. Consequently, significant use of auxiliary strip heating is required to meet the building heating load. We introduce innovative ASHP technologies as part of continuing efforts to eliminate auxiliary strip heat use and maximize heating COP with acceptable cost-effectiveness and reliability. These innovative ASHP were developed using tandem compressors, which are capable of augmenting heating capacity at low temperatures and maintain superior part-load operation efficiency at moderate temperatures. Two options of tandem compressors were studied; the first employs two identical, single-speed compressors, and the second employs two identical, vapor-injection compressors. The investigations were based on system modeling and laboratory evaluation. Both designs have successfully met the performance criteria. Laboratory evaluation showed that the tandem, single-speed compressor ASHP system is able to achieve heating COP = 4.2 at 47 F (8.3 C), COP = 2.9 at 17 F (-8.3 C), and 76% rated capacity and COP = 1.9 at -13 F (-25 C). This yields a HSPF = 11.0 (per AHRI 210/240). The tandem, vapor-injection ASHP is able to reach heating COP = 4.4 at 47 F, COP = 3.1 at 17 F, and 88% rated capacity and COP = 2.0 at -13 F. This yields a HSPF = 12.0. The system modeling and further laboratory evaluation are presented in the paper.

  7. District heating from Forsmark

    International Nuclear Information System (INIS)

    1980-11-01

    The district heating system of Greater Stockholm must be based on other energy sources than oil. Two alternatives are assessed, namely heat from Forsmark or a coal fueled plant in the region of Stockholm. Forsmark 3 can produce both electricity and heat from the year 1988 on. The capacity can be increased by coal fueled blocks. For low electricity use, 115 TWh in the year 1990, the Forsmark alternative will be profitable. The alternative will be profitable. The alternative with a fossile fuelled plant will be profitable when planning for high consumption of electricity, 125 TWh. The Forsmark alternative means high investments and the introduction of new techniques. (G.B.)

  8. Nuclear power for district heating

    International Nuclear Information System (INIS)

    Lyon, R.B.; Sochaski, R.O.

    1975-09-01

    Current district heating trends are towards an increasing use of electricity. This report concerns the evaluation of an alternative means of energy supply - the direct use of thermal energy from CANDU nuclear stations. The energy would be transmitted via a hot fluid in a pipeline over distances of up to 40 km. Advantages of this approach include a high utilization of primary energy, with a consequent reduction in installed capacity, and load flattening due to inherent energy storage capacity and transport delays. Disadvantages include the low load factors for district heating, the high cost of the distribution systems and the necessity for large-scale operation for economic viability. This requirement for large-scale operation from the beginning could cause difficulty in the implementation of the first system. Various approaches have been analysed and costed for a specific application - the supply of energy to a district heating load centre in Toronto from the location of the Pickering reactor station about 40 km away. (author)

  9. Effect of pH Changes on Antioxidant Capacity and the Content of Betalain Pigments During the Heating of a Solution of Red Beet Betalains

    Directory of Open Access Journals (Sweden)

    Mikołajczyk-Bator Katarzyna

    2017-06-01

    Full Text Available Red beets and their products are mainly consumed after processing. In this study, the effect of pH on changes in antioxidant capacity (AC and the content of betalain pigments were analysed during the heating of a betalain preparation solution. With pH ranging from 4 to 9 during the heat-treatment, the content of red pigments decreased depending on the pH level of the sample. The losses of red pigments in the investigated betalain preparation solution increased along with rising pH levels of the heated solution. The greatest losses were recorded at pH of 9.0. An opposite correlation was observed for yellow pigments. The content of yellow pigments in the heated betalain preparation solution was increasing along with increasing pH. The most pronounced increase in the content of yellow pigments was found at pH of 6.5 and 7.0. At the same time, the heated betalain preparation solution was shown to exhibit a higher antioxidant capacity at pH of 6.0 (14.9 μmol Trolox/mL than at pH of 4.0 (12.6 μmol Trolox/mL. It was observed that the increase in the antioxidant capacity in heated betalain preparation solutions with pH in the 6.0–6.5 range occurred as a result of increased concentrations of neobetanin, assessed by HPLC, within the pH range from 5.0 to 6.5.

  10. Structures for handling high heat fluxes

    International Nuclear Information System (INIS)

    Watson, R.D.

    1990-01-01

    The divertor is recognized as one of the main performance limiting components for ITER. This paper reviews the critical issues for structures that are designed to withstand heat fluxes >5 MW/m 2 . High velocity, sub-cooled water with twisted tape inserts for enhanced heat transfer provides a critical heat flux limit of 40-60 MW/m 2 . Uncertainties in physics and engineering heat flux peaking factors require that the design heat flux not exceed 10 MW/m 2 to maintain an adequate burnout safety margin. Armor tiles and heat sink materials must have a well matched thermal expansion coefficient to minimize stresses. The divertor lifetime from sputtering erosion is highly uncertain. The number of disruptions specified for ITER must be reduced to achieve a credible design. In-situ plasma spray repair with thick metallic coatings may reduce the problems of erosion. Runaway electrons in ITER have the potential to melt actively cooled components in a single event. A water leak is a serious accident because of steam reactions with hot carbon, beryllium, or tungsten that can mobilize large amounts of tritium and radioactive elements. If the plasma does not shutdown immediately, the divertor can melt in 1-10 s after a loss of coolant accident. Very high reliability of carbon tile braze joints will be required to achieve adequate safety and performance goals. Most of these critical issues will be addressed in the near future by operation of the Tore Supra pump limiters and the JET pumped divertor. An accurate understanding of the power flow out of edge of a DT burning plasma is essential to successful design of high heat flux components. (orig.)

  11. A Comparative Cycle and Refrigerant Simulation Procedure Applied on Air-Water Heat Pumps

    DEFF Research Database (Denmark)

    Mader, Gunda; Palm, Björn; Elmegaard, Brian

    2012-01-01

    A vapor compression heat pump absorbs heat from the environment at a low temperature level and rejects heat at a high temperature level. The bigger the difference between the two temperature levels the more challenging is it to gain high energy efficiency with a basic cycle layout as found in most...... small capacity heat pump applications today. Many of the applicable refrigerants also reach their technical limits regarding low vapor pressure for very low source temperatures and high discharge temperatures for high sink temperatures. These issues are especially manifest for air-water heat pumps. Many...... alternative cycle setups and refrigerants are known to improve the energy efficiency of a vapor compression cycle and reduce discharge temperatures. However not all of them are feasible for small capacity heat pumps from a cost and complexity point of view. This paper presents a novel numerical approach...

  12. MIMO Intensity-Modulation Channels: Capacity Bounds and High SNR Characterization

    KAUST Repository

    Chaaban, Anas

    2016-10-01

    The capacity of MIMO intensity modulation channels is studied. The nonnegativity of the transmit signal (intensity) poses a challenge on the precoding of the transmit signal, which limits the applicability of classical schemes in this type of channels. To resolve this issue, capacity lower bounds are developed by using precoding-free schemes. This is achieved by channel inversion or QR decomposition to convert the MIMO channel to a set of parallel channels. The achievable rate of a DC-offset SVD based scheme is also derived as a benchmark. Then, a capacity upper bound is derived and is shown to coincide with the achievable rate of the QR decomposition based scheme at high SNR, consequently characterizing the high-SNR capacity of the channel. The high-SNR gap between capacity and the achievable rates of the channel inversion and the DC-offset SVD based schemes is also characterized. Finally, the ergodic capacity of the channel is also briefly discussed.

  13. High heat flux cooling for accelerator targets

    International Nuclear Information System (INIS)

    Silverman, I.; Nagler, A.

    2002-01-01

    Accelerator targets, both for radioisotope production and for high neutron flux sources generate very high thermal power in the target material which absorbs the particles beam. Generally, the geometric size of the targets is very small and the power density is high. The design of these targets requires dealing with very high heat fluxes and very efficient heat removal techniques in order to preserve the integrity of the target. Normal heat fluxes from these targets are in the order of 1 kw/cm 2 and may reach levels of an order of magnitude higher

  14. Microwave-assisted preparation of Li3V2(PO4)3/C composite with high-rate capacity

    International Nuclear Information System (INIS)

    Yan, Ji; Mao, Wen-feng; Xie, Hui; Tang, Zhi-yuan; Yuan, Wei; Chen, Xue-cheng; Xu, Qiang; Ma, Li

    2012-01-01

    Highlights: ► High-rate Li 3 V 2 (PO 4 ) 3 /C is firstly reported via a microwave-assisted method. ► The reduced particle size is responsible for the improved high-rate performance. ► A discharge capacity of 100 mAh g −1 is obtained at 20 C charge–discharge rate. -- Abstract: A fast sol–gel assisted microwave heating approach has been developed for the synthesis of high-rate Li 3 V 2 (PO 4 ) 3 /C cathode material. This approach can synthesize Li 3 V 2 (PO 4 ) 3 /C particles with high purity and good crystallinity in 12 min at a low microwave power of 320 W. In the voltage range of 3.0–4.3 V, the obtained Li 3 V 2 (PO 4 ) 3 /C delivers a reversible discharge capacity of 100 mAh g −1 after 100 cycles at 20 °C, exhibiting excellent rate capability and cycling performance. The rate-recovery performance also suggests that the Li 3 V 2 (PO 4 ) 3 /C material possesses excellent structure stability after high-rate cycles, presenting excellent application value in high-power lithium ion batteries.

  15. Investigation of ammonia/water hybrid absorption/compression heat pumps for heat supply temperatures above 100 °C

    DEFF Research Database (Denmark)

    Jensen, Jonas Kjær; Reinholdt, Lars; Markussen, Wiebke Brix

    2014-01-01

    The hybrid absorption/compression heat pump (HACHP) using ammonia-water as working fluid is a promising technology for development of a high temperature industrial heat pump. This is due to two properties inherent to the use of zeotropic mixtures: non-isothermal phase change and reduced vapour...... using these components. A technically and economically feasible solution is defined as one that satisfies constraints on the coefficient of performance (COP), low and high pressure, compressor discharge temperature and volumetric heat capacity. The ammonia mass fraction of the rich solution...

  16. HEAT PUMP USING SUBSOIL WATERS AS LOW TEMPERATURE HEAT SOURCE

    Directory of Open Access Journals (Sweden)

    Denysova Alla

    2015-08-01

    Full Text Available One of the basic directions of perfection of heat supply systems is the tendency of transition to the low-temperature heating systems based on application of heat pump installations. We consider heat supply system with heat pump installations using subsoil waters. Numerical simulation of thermal processes in the elements of a single-stage and double-stage heat pump systems has been worked out. Values of depths of wells and their quantity, necessary for effective operation of the offered installations, and values of capacity of electric water pumps for subsoil waters unit are calculated. Capacity of compressor electric drive and coefficient of performance of heat pump for the conditions of the city of Odessa are presented.

  17. Numerical Investigation on the Heat Extraction Capacity of Dual Horizontal Wells in Enhanced Geothermal Systems Based on the 3-D THM Model

    Directory of Open Access Journals (Sweden)

    Zhixue Sun

    2018-01-01

    Full Text Available The Enhanced Geothermal System (EGS constructs an artificial thermal reservoir by hydraulic fracturing to extract heat economically from hot dry rock. As the core element of the EGS heat recovery process, mass and heat transfer of working fluid mainly occurs in fractures. Since the direction of the natural and induced fractures are generally perpendicular to the minimum principal stress in the formation, as an effective stimulation approach, horizontal well production could increase the contact area with the thermal reservoir significantly. In this paper, the thermal reservoir is developed by a dual horizontal well system and treated as a fractured porous medium composed of matrix rock and discrete fracture network. Using the local thermal non-equilibrium theory, a coupled THM mathematical model and an ideal 3D numerical model are established for the EGS heat extraction process. EGS heat extraction capacity is evaluated in the light of thermal recovery lifespan, average outlet temperature, heat production, electricity generation, energy efficiency and thermal recovery rate. The results show that with certain reservoir and production parameters, the heat production, electricity generation and thermal recovery lifespan can achieve the commercial goal of the dual horizontal well system, but the energy efficiency and overall thermal recovery rate are still at low levels. At last, this paper puts forward a series of optimizations to improve the heat extraction capacity, including production conditions and thermal reservoir construction design.

  18. Survey of high-temperature nuclear heat application

    International Nuclear Information System (INIS)

    Kirch, N.; Schaefer, M.

    1984-01-01

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

  19. Fabrication and Characterization of SnO2/Graphene Composites as High Capacity Anodes for Li-Ion Batteries

    Directory of Open Access Journals (Sweden)

    Abirami Dhanabalan

    2013-11-01

    Full Text Available Tin-oxide and graphene (TG composites were fabricated using the Electrostatic Spray Deposition (ESD technique, and tested as anode materials for Li-ion batteries. The electrochemical performance of the as-deposited TG composites were compared to heat-treated TG composites along with pure tin-oxide films. The heat-treated composites exhibited superior specific capacity and energy density than both the as-deposited TG composites and tin oxide samples. At the 70th cycle, the specific capacities of the as-deposited and post heat-treated samples were 534 and 737 mA·h/g, respectively, and the corresponding energy densities of the as-deposited and heat-treated composites were 1240 and 1760 W·h/kg, respectively. This improvement in the electrochemical performance of the TG composite anodes as compared to the pure tin oxide samples is attributed to the synergy between tin oxide and graphene, which increases the electrical conductivity of tin oxide and helps alleviate volumetric changes in tin-oxide during cycling.

  20. Combined Heat and Power Dispatch Considering Heat Storage of Both Buildings and Pipelines in District Heating System for Wind Power Integration

    Directory of Open Access Journals (Sweden)

    Ping Li

    2017-06-01

    Full Text Available The strong coupling between electric power and heat supply highly restricts the electric power generation range of combined heat and power (CHP units during heating seasons. This makes the system operational flexibility very low, which leads to heavy wind power curtailment, especially in the region with a high percentage of CHP units and abundant wind power energy such as northeastern China. The heat storage capacity of pipelines and buildings of the district heating system (DHS, which already exist in the urban infrastructures, can be exploited to realize the power and heat decoupling without any additional investment. We formulate a combined heat and power dispatch model considering both the pipelines’ dynamic thermal performance (PDTP and the buildings’ thermal inertia (BTI, abbreviated as the CPB-CHPD model, emphasizing the coordinating operation between the electric power and district heating systems to break the strong coupling without impacting end users’ heat supply quality. Simulation results demonstrate that the proposed CPB-CHPD model has much better synergic benefits than the model considering only PDTP or BTI on wind power integration and total operation cost savings.

  1. Development of plate-fin heat exchanger for intermediate heat exchanger of high-temperature gas cooled reactor. Fabrication process, high-temperature strength and creep-fatigue life prediction of plate-fin structure made of Hastelloy X

    International Nuclear Information System (INIS)

    Mizokami, Yorikata; Igari, Toshihide; Nakashima, Keiichi; Kawashima, Fumiko; Sakakibara, Noriyuki; Kishikawa, Ryouji; Tanihira, Masanori

    2010-01-01

    The helium/helium heat exchanger (i.e., intermediate heat exchanger: IHX) of a high-temperature gas-cooled reactor (HTGR) system with nuclear heat applications is installed between a primary system and a secondary system. IHX is operated at the highest temperature of 950degC and has a high capacity of up to 600 MWt. A plate-fin-type heat exchanger is the most suitable for IHX to improve construction cost. The purpose of this study is to develop an ultrafine plate-fin-type heat exchanger with a finer pitch fin than a conventional technology. In the first step, fabrication conditions of the ultrafine plate fin were optimized by press tests. In the second step, a brazing material was selected from several candidates through brazing tests of rods, and brazing conditions were optimized for plate-fin structures. In the third step, tensile strength, creep rupture, fatigue, and creep-fatigue tests were performed as typical strength tests for plate-fin structures. The obtained data were compared with those of the base metal and plate-fin element fabricated from SUS316. Finally, the accuracy of the creep-fatigue life prediction using both the linear cumulative damage rule and the equivalent homogeneous solid method was confirmed through the evaluation of creep-fatigue test results of plate-fin structures. (author)

  2. Construction and Capacity Analysis of High-Rank LoS MIMO Channels in High Speed Railway Scenarios

    Directory of Open Access Journals (Sweden)

    Jingya Yang

    2012-01-01

    Full Text Available The validity of the maximum capacity criterion applied to realize high-rank line-of-sight (LoS multiple-input multiple-output (MIMO channels is investigated for high speed railway scenarios. Performance is evaluated by ergodic capacity. Numerical results demonstrate that by simply adjusting antenna spacing according to the maximum capacity criterion, significant capacity gains are achievable. We find relatively low sensitivity of the system to displacements from the optimal point and angle in relatively short range. Thus, we present two proposals to reconfigure antenna arrays so as to maximize LoS MIMO capacity in the high speed railway scenarios

  3. Wheat cultivars selected for high Fv /Fm under heat stress maintain high photosynthesis, total chlorophyll, stomatal conductance, transpiration and dry matter.

    Science.gov (United States)

    Sharma, Dew Kumari; Andersen, Sven Bode; Ottosen, Carl-Otto; Rosenqvist, Eva

    2015-02-01

    The chlorophyll fluorescence parameter Fv /Fm reflects the maximum quantum efficiency of photosystem II (PSII) photochemistry and has been widely used for early stress detection in plants. Previously, we have used a three-tiered approach of phenotyping by Fv /Fm to identify naturally existing genetic variation for tolerance to severe heat stress (3 days at 40°C in controlled conditions) in wheat (Triticum aestivum L.). Here we investigated the performance of the previously selected cultivars (high and low group based on Fv /Fm value) in terms of growth and photosynthetic traits under moderate heat stress (1 week at 36/30°C day/night temperature in greenhouse) closer to natural heat waves in North-Western Europe. Dry matter accumulation after 7 days of heat stress was positively correlated to Fv /Fm . The high Fv /Fm group maintained significantly higher total chlorophyll and net photosynthetic rate (PN ) than the low group, accompanied by higher stomatal conductance (gs ), transpiration rate (E) and evaporative cooling of the leaf (ΔT). The difference in PN between the groups was not caused by differences in PSII capacity or gs as the variation in Fv /Fm and intracellular CO2 (Ci ) was non-significant under the given heat stress. This study validated that our three-tiered approach of phenotyping by Fv /Fm performed under increasing severity of heat was successful in identifying wheat cultivars differing in photosynthesis under moderate and agronomically more relevant heat stress. The identified cultivars may serve as a valuable resource for further studies to understand the physiological mechanisms underlying the genetic variability in heat sensitivity of photosynthesis. © 2014 Scandinavian Plant Physiology Society.

  4. Effect of radiant heat transfer on the performance of high temperature heat exchanger

    International Nuclear Information System (INIS)

    Mori, Yasuo; Hijikata, Kunio; Yamada, Yukio

    1975-01-01

    The development of high temperature gas-cooled reactors is motivated by the consideration of the application of nuclear heat for industrial uses or direct steelmaking and chemical processes. For these purposes, reliable and efficient heat exchangers should be developed. This report analyzes the effect of radiant heat transfer on the performance of high temperature heat exchangers. The heat transfer model is as follows: the channel composed with two parallel adiabatic walls is divided with one parallel plate between the walls. Non-radiative fluid flows in the two separated channels in opposite direction. Heat transfer equations for this system were obtained, and these equations were solved by some approximate method and numerical analysis. The effect of radiation on heat transfer became larger as the radiant heat transfer between two walls was larger. In the heat exchangers of counter flow type, the thermal efficiency is controlled with three parameters, namely radiation-convection parameter, Stanton number and temperature difference. The thermal efficiency was larger with the increase of these parameters. (Iwase, T.)

  5. 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. 

  6. Crack-resistant polyimide coating for high-capacity battery anodes

    Science.gov (United States)

    Li, Yingshun; Wang, Shuo; Lee, Pui-Kit; He, Jieqing; Yu, Denis Y. W.

    2017-10-01

    Electrode cracking is a serious problem that hinders the application of many next-generation high-capacity anode materials for lithium-ion batteries. Even though nano-sizing the material can reduce fracturing of individual particles, capacity fading is still observed due to large volume change and loss of contact in the electrode during lithium insertion and extraction. In this study, we design a crack-resistant high-modulus polyimide coating with high compressive strength which can hold multiple particles together during charge and discharge to maintain contact. The effectiveness of the coating is demonstrated on tin dioxide, a high-capacity large-volume-change material that undergoes both alloy and conversion reactions. The polyimide coating improves capacity retention of SnO2 from 80% to 100% after 80 cycles at 250 mA g-1. Stable capacity of 585 mAh g-1 can be obtained even at 500 mA g-1 after 300 cycles. Scanning electron microscopy and in-situ dilatometry confirm that electrode cracking is suppressed and thickness change is reduced with the coating. In addition, the chemically-stable polyimide film can separate the surface from direct contact with electrolyte, improving coulombic efficiency to ∼100%. We expect the novel strategy of suppressing electrode degradation with a crack-resistant coating can also be used for other alloy and conversion-based anodes.

  7. Heat transfer in high-level waste management

    International Nuclear Information System (INIS)

    Dickey, B.R.; Hogg, G.W.

    1979-01-01

    Heat transfer in the storage of high-level liquid wastes, calcining of radioactive wastes, and storage of solidified wastes are discussed. Processing and storage experience at the Idaho Chemical Processing Plant are summarized for defense high-level wastes; heat transfer in power reactor high-level waste processing and storage is also discussed

  8. Development of high capacity, high rate lithium ion batteries utilizing metal fiber conductive additives

    Science.gov (United States)

    Ahn, Soonho; Kim, Youngduk; Kim, Kyung Joon; Kim, Tae Hyung; Lee, Hyungkeun; Kim, Myung H.

    As lithium ion cells dominate the battery market, the performance improvement is an utmost concern among developers and researchers. Conductive additives are routinely employed to enhance electrode conductivity and capacity. Carbon particulates—graphite or carbon black powders—are conventional and popular choices as conductive fillers. However, percolation requirements of particles demand significant volumetric content of impalpable, and thereby high area conductive fillers. As might be expected, the electrode active surface area escalates unnecessarily, resulting in overall increase in reaction with electrolytes and organic solvents. The increased reactions usually manifest as an irreversible loss of anode capacity, gradual oxidation and consumption of electrolyte on the cathode—which causes capacity decline during cycling—and an increased threat to battery safety by gas evolution and exothermic solvent oxidation. In this work we have utilized high aspect ratio, flexible, micronic metal fibers as low active area and high conductivity additives. The metal fibers appear well dispersed within the electrode and to satisfy percolation requirements very efficiently at very low volumetric content compared to conventional carbon-based conductive additives. Results from 18650-type cells indicate significant enhancements in electrode capacity and high rate capability while the irreversible capacity loss is negligible.

  9. When High-Capacity Readers Slow Down and Low-Capacity Readers Speed Up: Working Memory and Locality Effects.

    Science.gov (United States)

    Nicenboim, Bruno; Logačev, Pavel; Gattei, Carolina; Vasishth, Shravan

    2016-01-01

    We examined the effects of argument-head distance in SVO and SOV languages (Spanish and German), while taking into account readers' working memory capacity and controlling for expectation (Levy, 2008) and other factors. We predicted only locality effects, that is, a slowdown produced by increased dependency distance (Gibson, 2000; Lewis and Vasishth, 2005). Furthermore, we expected stronger locality effects for readers with low working memory capacity. Contrary to our predictions, low-capacity readers showed faster reading with increased distance, while high-capacity readers showed locality effects. We suggest that while the locality effects are compatible with memory-based explanations, the speedup of low-capacity readers can be explained by an increased probability of retrieval failure. We present a computational model based on ACT-R built under the previous assumptions, which is able to give a qualitative account for the present data and can be tested in future research. Our results suggest that in some cases, interpreting longer RTs as indexing increased processing difficulty and shorter RTs as facilitation may be too simplistic: The same increase in processing difficulty may lead to slowdowns in high-capacity readers and speedups in low-capacity ones. Ignoring individual level capacity differences when investigating locality effects may lead to misleading conclusions.

  10. When high-capacity readers slow down and low-capacity readers speed up: Working memory and locality effects

    Directory of Open Access Journals (Sweden)

    Bruno eNicenboim

    2016-03-01

    Full Text Available We examined the effects of argument-head distance in SVO and SOV languages (Spanish and German, while taking into account readers’ working memory capacity and controlling for expectation (Levy, 2008 and other factors. We predicted only locality effects, that is, a slow-down produced by increased dependency distance (Gibson, 2000; Lewis & Vasishth, 2005. Furthermore, we expected stronger locality effects for readers with low working memory capacity. Contrary to our predictions, low-capacity readers showed faster reading with increased distance, while high-capacity readers showed locality effects. We suggest that while the locality effects are compatible with memory-based explanations, the speedup of low-capacity readers can be explained by an increased probability of retrieval failure. We present a computational model based on ACT-R built under the previous assumptions, which is able to give a qualitative account for the present data and can be tested in future research. Our results suggest that in some cases, interpreting longer RTs as indexing increased processing difficulty and shorter RTs as facilitation may be too simplistic: The same increase in processing difficulty may lead to slowdowns in high-capacity readers and speedups in low-capacity ones. Ignoring individual level capacity differences when investigating locality effects may lead to misleading conclusions.

  11. Superfluid density and heat capacity measurements of 4He in porous gold

    International Nuclear Information System (INIS)

    Yoon, J.; Chan, M.

    1995-01-01

    Superfluid density of full pore 4 He as well as thin film 4 He confined in porous gold were measured as a function of temperature. The superfluid transition temperature of full pore was found to be 2.156 K. In both cases power law dependence on reduced temperature was found and the exponent was found to be the same as that of bulk 4 He. Porous gold is made by electrochemically leaching out silver from silver-gold alloy. The porous gold sample the authors fabricated has porosity of 55 with a diameter of 250 angstrom. Electron microscope picture shows that the structure of porous gold is exceedingly similar to that of Vycor. Heat capacity measurement of full pore 4 He in porous gold is in progress

  12. Medium Deep High Temperature Heat Storage

    Science.gov (United States)

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

    2015-04-01

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

  13. Steady state simulation of Joule heated ceramic melter for vitrification of high level liquid waste

    Energy Technology Data Exchange (ETDEWEB)

    Sugilal, G; Wattal, P K; Theyyunni, T K [Process Engineering and Systems Development Division, Bhabha Atomic Research Centre, Mumbai (India); Iyer, K N [Department of Mechanical Engineering, Indian Inst. of Tech., Mumbai (India)

    1994-06-01

    The Joule heated ceramic melter is emerging as an attractive alternative to metallic melters for high level waste vitrification. The inherent limitations with metallic melters viz., low capacity and short melter life, are overcome in a ceramic melter which can be adopted for continuous mode of operation. The ceramic melter has the added advantage of better operational flexibility. This paper describes the three dimensional model used for simulating the complex design conditions of the ceramic melter. (author).

  14. Steady state simulation of Joule heated ceramic melter for vitrification of high level liquid waste

    International Nuclear Information System (INIS)

    Sugilal, G.; Wattal, P.K.; Theyyunni, T.K.; Iyer, K.N.

    1994-01-01

    The Joule heated ceramic melter is emerging as an attractive alternative to metallic melters for high level waste vitrification. The inherent limitations with metallic melters viz., low capacity and short melter life, are overcome in a ceramic melter which can be adopted for continuous mode of operation. The ceramic melter has the added advantage of better operational flexibility. This paper describes the three dimensional model used for simulating the complex design conditions of the ceramic melter. (author)

  15. Thermodynamic properties of xanthone: Heat capacities, phase-transition properties, and thermodynamic-consistency analyses using computational results

    International Nuclear Information System (INIS)

    Chirico, Robert D.; Kazakov, Andrei F.

    2015-01-01

    Highlights: • Heat capacities were measured for the temperature range (5 to 520) K. • The enthalpy of combustion was measured and the enthalpy of formation was derived. • Thermodynamic-consistency analysis resolved inconsistencies in literature enthalpies of sublimation. • An inconsistency in literature enthalpies of combustion was resolved. • Application of computational chemistry in consistency analysis was demonstrated successfully. - Abstract: Heat capacities and phase-transition properties for xanthone (IUPAC name 9H-xanthen-9-one and Chemical Abstracts registry number [90-47-1]) are reported for the temperature range 5 < T/K < 524. Statistical calculations were performed and thermodynamic properties for the ideal gas were derived based on molecular geometry optimization and vibrational frequencies calculated at the B3LYP/6-31+G(d,p) level of theory. These results are combined with sublimation pressures from the literature to allow critical evaluation of inconsistent enthalpies of sublimation for xanthone, also reported in the literature. Literature values for the enthalpy of combustion of xanthone are re-assessed, a revision is recommended for one result, and a new value for the enthalpy of formation of the ideal gas is derived. Comparisons with thermophysical properties reported in the literature are made for all other reported and derived properties, where possible

  16. Thermal performance of a flat polymer heat pipe heat spreader under high acceleration

    International Nuclear Information System (INIS)

    Oshman, Christopher; Li, Qian; Liew, Li-Anne; Yang, Ronggui; Lee, Y C; Bright, Victor M; Sharar, Darin J; Jankowski, Nicholas R; Morgan, Brian C

    2012-01-01

    This paper presents the fabrication and application of a micro-scale hybrid wicking structure in a flat polymer-based heat pipe heat spreader, which improves the heat transfer performance under high adverse acceleration. The hybrid wicking structure which enhances evaporation and condensation heat transfer under adverse acceleration consists of 100 µm high, 200 µm wide square electroplated copper micro-pillars with 31 µm wide grooves for liquid flow and a woven copper mesh with 51 µm diameter wires and 76 µm spacing. The interior vapor chamber of the heat pipe heat spreader was 30×30×1.0 mm 3 . The casing of the heat spreader is a 100 µm thick liquid crystal polymer which contains a two-dimensional array of copper-filled vias to reduce the overall thermal resistance. The device performance was assessed under 0–10 g acceleration with 20, 30 and 40 W power input on an evaporator area of 8×8 mm 2 . The effective thermal conductivity of the device was determined to range from 1653 W (m K) −1 at 0 g to 541 W (m K) −1 at 10 g using finite element analysis in conjunction with a copper reference sample. In all cases, the effective thermal conductivity remained higher than that of the copper reference sample. This work illustrates the possibility of fabricating flexible, polymer-based heat pipe heat spreaders compatible with standardized printed circuit board technologies that are capable of efficiently extracting heat at relatively high dynamic acceleration levels. (paper)

  17. HEAT AND MOISTURE EXCHANGE CAPACITY OF THE UPPER RESPIRATORY TRACT AND THE EFFECT OF TRACHEOTOMY BREATHING ON ENDOTRACHEAL CLIMATE

    NARCIS (Netherlands)

    Scheenstra, Renske J.; Muller, Sara H.; Vincent, Andrew; Hilgers, Frans J. M.

    2011-01-01

    Background. The aim of this study was to assess the heat and moisture exchange (HME) capacity of the upper respiratory tract and the effect of tracheotomy breathing on endotracheal climate in patients with head and neck cancer. Methods. We plotted the subglottic temperature and humidity measurements

  18. Heat and moisture exchange capacity of the upper respiratory tract and the effect of tracheotomy breathing on endotracheal climate

    NARCIS (Netherlands)

    Scheenstra, R.J.; Muller, S.H.; Vincent, A.; Hilgers, F.J.M.

    2011-01-01

    Background. The aim of this study was to assess the heat and moisture exchange (HME) capacity of the upper respiratory tract and the effect of tracheotomy breathing on endotracheal climate in patients with head and neck cancer. Methods. We plotted the subglottic temperature and humidity measurements

  19. High capacity argon extraction and purification system. [Suitable for age estimation of rocks

    Energy Technology Data Exchange (ETDEWEB)

    Balogh, K; Morik, Gy [Magyar Tudomanyos Akademia Atommag Kutato Intezete, Debrecen

    1979-01-01

    A high capacity metal-glass argon extraction and purification system has been developed for K/Ar dating of geologic materials. A set of samples can be loaded simultaneously and degassed in turn in the system by high frequency induction heating in a molybdenum crucible. The argon purification is carried out by titanium sponge, molecular sieve, copper oxide and glass and charcoal filled traps cooled by liquid nitrogen. The /sup 38/Ar spike and the atmospheric argon used for calibrating the mass spectrometer are dispensed by a gas-pipette system. 80-120 minutes after starting the degassing of the sample, the purified argon can be introduced into the mass spectrometer; the gettering materials regenerate in 1-5 hours, thus 1-3 samples may be analysed a day. The atmospheric argon inflow during an experimental process is less than 5x10/sup -8/ cc STP.

  20. To Selection of Small-Capacity Turbine Type and Rated Conditions

    Directory of Open Access Journals (Sweden)

    N. B. Karnitsky

    2010-01-01

    Full Text Available Profitability of industrial-heating boiler transition to mini-TPP is revealed in the paper. The paper presents a comparative analysis of high- and low-speed turbines of small capacity.

  1. A heat pipe solar collector system for winter heating in Zhengzhou city, China

    Directory of Open Access Journals (Sweden)

    Zheng Hui-Fan

    2017-01-01

    Full Text Available A heat pipe solar collector system for winter heating is investigated both experimentally and theoretically. The hourly heat collecting capacity, water temperature and contribution rate of solar collector system based on Zhengzhou city typical sunshine are calculated. The study reveals that the heat collecting capacity and water temperature increases initially and then decreases, and the solar collector system can provide from 40% to 78% heating load for a 200 m2 villa with in Zhengzhou city from November to March.

  2. Experimental results for hydrocarbon refrigerant vaporization in brazed plate heat exchangers at high pressure

    OpenAIRE

    Desideri, Adriano; Rhyl Kaern, Martin; Ommen Schmidt, Torben; Wronski, Jorrit; Quoilin, Sylvain; Lemort, Vincent; Haglind, Fredrik

    2016-01-01

    In recent years the interest in small capacity organic Rankine cycle (ORC) power systems for harvesting low quality waste thermal energy from industrial processes has been steadily growing. Micro ORC systems are normally equipped with brazed plate heat exchangers which allows for efficient heat transfer with a compact design. An accurate prediction of the heat transfer process characterizing these devices is required from the design phase to the development of model- based control strategies....

  3. Pressure drop and heat transfer characteristics of a high-temperature printed circuit heat exchanger

    International Nuclear Information System (INIS)

    Chen, Minghui; Sun, Xiaodong; Christensen, Richard N.; Skavdahl, Isaac; Utgikar, Vivek; Sabharwall, Piyush

    2016-01-01

    Highlights: • Pressure drop and heat transfer characteristics of a high-temperature printed circuit heat exchanger have been obtained. • Comparisons of experimental data and available correlations have been performed. • New Fanning friction factor and heat transfer correlations for the test PCHE are developed. - Abstract: Printed circuit heat exchanger (PCHE) is one of the leading intermediate heat exchanger (IHX) candidates to be employed in the very-high-temperature gas-cooled reactors (VHTRs) due to its capability for high-temperature, high-pressure applications. In the current study, a reduced-scale zigzag-channel PCHE was fabricated using Alloy 617 plates for the heat exchanger core and Alloy 800H pipes for the headers. The pressure drop and heat transfer characteristics of the PCHE were investigated experimentally in a high-temperature helium test facility (HTHF) at The Ohio State University. The PCHE helium inlet temperatures and pressures were varied up to 464 °C/2.7 MPa for the cold side and 802 °C/2.7 MPa for the hot side, respectively, while the maximum helium mass flow rates on both sides of the PCHE reached 39 kg/h. The corresponding maximum channel Reynolds number was approximately 3558, covering the laminar flow and laminar-to-turbulent flow transition regimes. New pressure drop and heat transfer correlations for the current zigzag channels with rounded bends were developed based on the experimental data. Comparisons between the experimental data and the results obtained from the available PCHE and straight circular pipe correlations were conducted. Compared to the heat transfer performance in straight circular pipes, the zigzag channels provided little advantage in the laminar flow regime but significant advantage near the transition flow regime.

  4. High Energy Antimatter Telescope (HEAT) Balloon Experiment

    Science.gov (United States)

    Beatty, J. J.

    1995-01-01

    This grant supported our work on the High Energy Antimatter Telescope(HEAT) balloon experiment. The HEAT payload is designed to perform a series of experiments focusing on the cosmic ray positron, electron, and antiprotons. Thus far two flights of the HEAT -e+/- configuration have taken place. During the period of this grant major accomplishments included the following: (1) Publication of the first results of the 1994 HEAT-e+/- flight in Physical Review Letters; (2) Successful reflight of the HEAT-e+/- payload from Lynn Lake in August 1995; (3) Repair and refurbishment of the elements of the HEAT payload damaged during the landing following the 1995 flight; and (4) Upgrade of the ground support equipment for future flights of the HEAT payload.

  5. Glass heat capacity and its abrupt change in glass transition region

    DEFF Research Database (Denmark)

    Yue, Yuanzheng; Smedskjær, Morten Mattrup; Mauro, John C.

    cover a large range of glass formers from metallic to non-metallic glasses. To conduct this study we convert the units of all the Cp data from J/mol K and J/g K to J/g-atom K. This study will provide insight into the correlations among chemical bonding, microstructure structure, liquid fragility, glass......Glass transition (GT) has been a fascinating, but challenging subject in the condensed matter science over decades. Despite progress in understanding GT, many crucial problems still need to be clarified. One of the problems deals with the microscopic origin of abrupt change of heat capacity (Cp......) around glass transition. Here we study this problem through two approaches. First, we analyze the Cp change with temperature on homologous series of glass formers (i.e., with regular compositional substitution). Second, we do the same on non-homologous systems (e.g. without regular compositional...

  6. The impact of heat waves on electricity spot markets

    International Nuclear Information System (INIS)

    Pechan, Anna; Eisenack, Klaus

    2014-01-01

    Thermoelectric power plants depend on cooling water drawn from water bodies. Low river run-off and/or high water temperatures limit a plant's production capacity. This problem may intensify with climate change. Our study quantifies the impact of forced capacity reductions on market prices, production costs, consumer and producer surplus, as well as emissions by means of a bottom-up power generation system model. First, we simulate the German electricity spot market during the heat wave of 2006. Then we conduct a sensitivity study that accounts for future climatic and technological conditions. We find an average price increase of 11% during the heat wave 2006, which is even more pronounced during times of peak demand. Production costs accumulate to an additional but moderate 16 m. Due to the price increase, producers gain from the heat wave, whereas consumers disproportionately bear the costs. Carbon emissions in the German electricity sector increase during the heat wave. The price and cost effects are more pronounced and increase significantly if assumptions on heat-sensitive demand, hydropower capacity, net exports, and capacity reductions are tightened. These are potential additional effects of climate change. Hence, if mitigation fails or is postponed globally, the impacts on the current energy system are very likely to rise. Increases in feed-in from renewable resources and demand-side management can counter the effects to a considerable degree. Countries with a shift toward a renewable energy supply can be expected to be much less susceptible to cooling water scarcity than those with a high share of nuclear and coal-fired power plants. - Highlights: • We quantify the impact of thermal capacity reductions on the electricity market. • German heat wave 2006 caused moderate rise in production costs. • Capacity reductions have substantial impact on prices and raise producer surplus. • Impacts on prices, production cost and surplus amplify under climate

  7. Aluminum and silicon based phase change materials for high capacity thermal energy storage

    International Nuclear Information System (INIS)

    Wang, Zhengyun; Wang, Hui; Li, Xiaobo; Wang, Dezhi; Zhang, Qinyong; Chen, Gang; Ren, Zhifeng

    2015-01-01

    Six compositions of aluminum (Al) and silicon (Si) based materials: 87.8Al-12.2Si, 80Al–20Si, 70Al–30Si, 60Al–40Si, 45Al–40Si–15Fe, and 17Al–53Si–30Ni (atomic ratio), were investigated for potentially high thermal energy storage (TES) application from medium to high temperatures (550–1200 °C) through solid–liquid phase change. Thermal properties such as melting point, latent heat, specific heat, thermal diffusivity and thermal conductivity were investigated by differential scanning calorimetry and laser flash apparatus. The results reveal that the thermal storage capacity of the Al–Si materials increases with increasing Si concentration. The melting point and latent heat of 45Al–40Si–15Fe and 17Al–53Si–30Ni are ∼869 °C and ∼562 J g −1 , and ∼1079 °C and ∼960 J g −1 , respectively. The measured thermal conductivity of Al–Si binary materials depend on Si concentration and is higher than 80 W m −1  K −1 from room temperature to 500 °C, which is almost two orders of magnitude higher than those of salts that are commonly used phase change material for thermal energy storage. - Highlights: • Six kinds of materials were investigated for thermal energy storage (550–1200 °C). • Partial melting of Al–Si materials show progressively changing temperatures. • Studied materials can be used in three different working temperature ranges. • Materials are potentially good candidates for thermal energy storage applications.

  8. Sources for high frequency heating. Performance and limitations

    International Nuclear Information System (INIS)

    Le Gardeur, R.

    1976-01-01

    The various problems encountered in high frequency heating of plasmas can be decomposed into three spheres of action: theoretical development, antenna designing, and utilization of power sources. By classifying heating into three spectral domains, present and future needs are enumerated. Several specific antenna designs are treated. High frequency power sources are reviewed. The actual development of the gyratron is discussed in view of future needs in very high frequency heating of plasmas [fr

  9. Free-space optical communications with peak and average constraints: High SNR capacity approximation

    KAUST Repository

    Chaaban, Anas

    2015-09-07

    The capacity of the intensity-modulation direct-detection (IM-DD) free-space optical channel with both average and peak intensity constraints is studied. A new capacity lower bound is derived by using a truncated-Gaussian input distribution. Numerical evaluation shows that this capacity lower bound is nearly tight at high signal-to-noise ratio (SNR), while it is shown analytically that the gap to capacity upper bounds is a small constant at high SNR. In particular, the gap to the high-SNR asymptotic capacity of the channel under either a peak or an average constraint is small. This leads to a simple approximation of the high SNR capacity. Additionally, a new capacity upper bound is derived using sphere-packing arguments. This bound is tight at high SNR for a channel with a dominant peak constraint.

  10. Abiotic and biotic determinants of leaf carbon exchange capacity from tropical to high boreal biomes

    Science.gov (United States)

    Smith, N. G.; Dukes, J. S.

    2016-12-01

    Photosynthesis and respiration on land represent the two largest fluxes of carbon dioxide between the atmosphere and the Earth's surface. As such, the Earth System Models that are used to project climate change are high sensitive to these processes. Studies have found that much of this uncertainty is due to the formulation and parameterization of plant photosynthetic and respiratory capacity. Here, we quantified the abiotic and biotic factors that determine photosynthetic and respiratory capacity at large spatial scales. Specifically, we measured the maximum rate of Rubisco carboxylation (Vcmax), the maximum rate of Ribulose-1,5-bisphosphate regeneration (Jmax), and leaf dark respiration (Rd) in >600 individuals of 98 plant species from the tropical to high boreal biomes of Northern and Central America. We also measured a bevy of covariates including plant functional type, leaf nitrogen content, short- and long-term climate, leaf water potential, plant size, and leaf mass per area. We found that plant functional type and leaf nitrogen content were the primary determinants of Vcmax, Jmax, and Rd. Mean annual temperature and mean annual precipitation were not significant predictors of these rates. However, short-term climatic variables, specifically soil moisture and air temperature over the previous 25 days, were significant predictors and indicated that heat and soil moisture deficits combine to reduce photosynthetic capacity and increase respiratory capacity. Finally, these data were used as a model benchmarking tool for the Community Land Model version 4.5 (CLM 4.5). The benchmarking analyses determined errors in the leaf nitrogen allocation scheme of CLM 4.5. Under high leaf nitrogen levels within a plant type the model overestimated Vcmax and Jmax. This result suggested that plants were altering their nitrogen allocation patterns when leaf nitrogen levels were high, an effect that was not being captured by the model. These data, taken with models in mind

  11. Heat capacity of liquids: A hydrodynamic approach

    Directory of Open Access Journals (Sweden)

    T. Bryk

    2015-03-01

    Full Text Available We study autocorrelation functions of energy, heat and entropy densities obtained by molecular dynamics simulations of supercritical Ar and compare them with the predictions of the hydrodynamic theory. It is shown that the predicted by the hydrodynamic theory single-exponential shape of the entropy density autocorrelation functions is perfectly reproduced for small wave numbers by the molecular dynamics simulations and permits the calculation of the wavenumber-dependent specific heat at constant pressure. The estimated wavenumber-dependent specific heats at constant volume and pressure, Cv(k and Cp(k, are shown to be in the long-wavelength limit in good agreement with the macroscopic experimental values of Cv and Cp for the studied thermodynamic points of supercritical Ar.

  12. Overall conductance and heat transfer area minimization of refrigerators and heat pumps with finite heat reservoirs

    International Nuclear Information System (INIS)

    Sarkar, J.; Bhattacharyya, Souvik

    2007-01-01

    In the present study, the overall conductance and the overall heat transfer area per unit capacity of refrigeration and heat pump systems have been minimized analytically considering both internal and external irreversibilities with variable temperature (finite capacity) heat reservoirs. Hot and cold side refrigerant temperatures, conductance and heat transfer area ratios have been optimized to attain this goal. The results have been verified with the more elaborate numerical optimization results obtained for ammonia based vapour compression refrigeration and heat pump systems working with variable temperature reservoirs. It is observed that the analytical results for optimum refrigerant temperatures, minimum overall conductance and heat transfer area deviate marginally from the numerically optimized results (within 1%), if one assumes a constant heat rejection temperature. The deviation of minimum overall conductance and heat transfer area is more (about 20%), if one considers both the desuperheating and condensation regions separately. However, in the absence of complex and elaborate numerical models, the simple analytical results obtained here can be used as reasonably accurate preliminary guidelines for optimization of refrigeration and heat pump systems

  13. On the High Altitude Platform (HAP W-CDMA System Capacity

    Directory of Open Access Journals (Sweden)

    L. de Haro-Ariet

    2004-06-01

    Full Text Available The performance of a downlink power control model, based on a n-thpower distance law, is evaluated for high altitude platform station(HAPS W-CDMA systems. The downlink capacity using this model iscompared with the uplink capacity. It is shown that the uplink capacityis higher than the downlink capacity.

  14. Modeling of a heat sink and high heat flux vapor chamber

    Science.gov (United States)

    Vadnjal, Aleksander

    An increasing demand for a higher heat flux removal capability within a smaller volume for high power electronics led us to focus on a novel cold plate design. A high heat flux evaporator and micro channel heat sink are the main components of a cold plate which is capable of removing couple of 100 W/cm2. In order to describe performance of such porous media device a proper modeling has to be addressed. A universal approach based on the volume average theory (VAT) to transport phenomena in porous media is shown. An approach on how to treat the closure for momentum and energy equations is addressed and a proper definition for friction factors and heat transfer coefficients are discussed. A numerical scheme using a solution to Navier-Stokes equations over a representative elementary volume (REV) and the use of VAT is developed to show how to compute friction factors and heat transfer coefficients. The calculation show good agreement with the experimental data. For the heat transfer coefficient closure, a proper average for both fluid and solid is investigated. Different types of heating are also investigated in order to determine how it influences the heat transfer coefficient. A higher heat fluxes in small area condensers led us to the micro channels in contrast to the classical heat fin design. A micro channel can have various shapes to enhance heat transfer, but the shape that will lead to a higher heat flux removal with a moderate pumping power needs to be determined. The standard micro-channel terminology is usually used for channels with a simple cross section, e.g. square, round, triangle, etc., but here the micro channel cross section is going to be expanded to describe more complicated and interconnected micro scale channel cross sections. The micro channel geometries explored are pin fins (in-line and staggered) and sintered porous micro channels. The problem solved here is a conjugate problem involving two heat transfer mechanisms; (1) porous media

  15. Flexible use of electricity in heat-only district heating plants

    Directory of Open Access Journals (Sweden)

    Erik Trømborg

    2017-01-01

    Full Text Available European energy systems are in a period of significant transition, with the increasing shares of variable renewable energy (VRE and less flexible fossil-based generation units as predominant factors. The supply-side changes are expected to cause large short-term electricity price volatility. More frequent periods of low electricity prices may mean that electric use in flexible heating systems will become more profitable, and such flexible heating systems may, in turn, improve the integration of increasing shares of VRE. The objective of this study is to analyze the likely future of Nordic electricity price levels and variations and how the expected prices might affect the use of electricity and thermal storage in heat-only district heating plants. We apply the North European energy market model Balmorel to provide scenarios for future hourly electricity prices in years with normal, high, and low inflow levels to the hydro power system. The simulation tool energyPRO is subsequently applied to quantify how these electricity price scenarios affect the hourly use of thermal storage and individual boilers in heat-only district heating plants located in Norway. The two studied example plants use wood chips or heat pump as base load representing common technologies for district heating in Norway. The Balmorel results show that annual differences in inflow is still a decisive factor for Norwegian and Nordic electricity prices in year 2030 and that short-term (daily price variability is expected to increase. In the plant-level simulations, we find that tank storage, which is currently installed in only a few district heating plants in Norway, is a profitable flexibility option that will significantly reduce the use of fossil peak load in both biomass and heat-pump-based systems. Installation of an electric boiler in addition to tank storage is profitable in the heat pump system due to the limited capacity of the heat pump. Electricity will hence, to a

  16. Low-temperature heat capacities and thermodynamic properties of ethylenediammonium tetrachlorozincate chloride (C2H10N2)2(ZnCl4)Cl2

    International Nuclear Information System (INIS)

    He, Dong-Hua; Di, You-Ying; Wang, Bin; Dan, Wen-Yan; Tan, Zhi-Cheng

    2010-01-01

    The ethylenediammonium tetrachlorozincate chloride (C 2 H 10 N 2 ) 2 (ZnCl 4 )Cl 2 was synthesized. Chemical analysis, elemental analysis, and X-ray crystallography were applied to characterize the composition and crystal structure of the complex. Low-temperature heat capacities of the compound were measured by a precision automatic adiabatic calorimeter over the temperature range from T = 77-377 K. A polynomial equation of heat capacities as a function of the reduced temperature was fitted by a least square method. Based on the polynomial equation, the smoothed heat capacities and thermodynamic functions of the title compound relative to the standard reference temperature 298.15 K were calculated at intervals of 5 K. A thermochemical cycle was designed and the enthalpy change of the solid phase reaction of ethylenediamine dihydrochloride with zinc chloride was determined to be Δ r H m o =-(17.9±0.6)kJmol -1 by an isoperibol solution-reaction calorimeter. Finally, the standard molar enthalpy of formation of the title compound was derived to be Δ f H m o [(C 2 H 10 N 2 ) 2 (ZnCl 4 )Cl 2 ,s]=-(1514.4±2.7)kJmol -1 in accordance with Hess law.

  17. Apparent molar volumes and apparent molar heat capacities of Pr(NO3)3(aq), Gd(NO3)3(aq), Ho(NO3)3(aq), and Y(NO3)3(aq) at T (288.15, 298.15, 313.15, and 328.15) K and p = 0.1 MPa

    International Nuclear Information System (INIS)

    Hakin, Andrew W.; Liu Jinlian; Erickson, Kristy; Munoz, Julie-Vanessa; Rard, Joseph A.

    2005-01-01

    Relative densities and relative massic heat capacities have been measured for acidified solutions of Y(NO 3 ) 3 (aq), Pr(NO 3 ) 3 (aq), and Gd(NO 3 ) 3 (aq) at T = (288.15, 298.15, 313.15, and 328.15) K and p = 0.1 MPa. In addition, relative densities and massic heat capacities have been measured at the same temperatures and pressure for Y(NO 3 ) 3 (aq) and Ho(NO 3 ) 3 (aq) solutions without excess acid (n.b. measurements at T = 328.15 K for Ho(NO 3 ) 3 (aq) were not performed due to the limited volume of solution available). Apparent molar volumes and apparent molar heat capacities for the aqueous salt solutions have been calculated from the experimental apparent molar properties of the acidified solutions using Young's rule, whereas the apparent molar properties of the solutions without excess acid were calculated directly from the measured densities and massic heat capacities. The two sets of data for the Y(NO 3 ) 3 (aq) systems provide a check of the internal consistency of the Young's rule approach we have utilised. The concentration dependences of the apparent molar volumes and heat capacities of the aqueous salt solutions have been modelled at each investigated temperature using the Pitzer ion interaction equations to yield apparent molar properties at infinite dilution. Complex formation within the aqueous rare earth nitrate systems is discussed qualitatively by probing the concentration dependence of apparent molar volumes and heat capacities. In spite of the complex formation in the aqueous rare earth nitrate systems, there is a high degree of self-consistency between the apparent molar volumes and heat capacities at infinite dilution reported in this manuscript and those previously reported for aqueous rare earth perchlorates

  18. Heat exchangers and recuperators for high temperature waste gases

    Science.gov (United States)

    Meunier, H.

    General considerations on high temperature waste heat recovery are presented. Internal heat recovery through combustion air preheating and external heat recovery are addressed. Heat transfer and pressure drop in heat exchanger design are discussed.

  19. Heat capacity and point-contact spectra of the melt-spun cubic RECu.sub.5./sub. compounds (RE - heavy rare earths)

    Czech Academy of Sciences Publication Activity Database

    Reiffers, M.; Ilkovič, S.; Idzikowski, B.; Šebek, Josef; Šantavá, Eva

    2010-01-01

    Roč. 200, č. 3 (2010), 032061/1-032061/4 ISSN 1742-6588. [International Conference on Magnetism - ICM 2009. Karlsruhe, 26.07.2009-31.07.2009] Institutional research plan: CEZ:AV0Z10100520 Keywords : heat capacity * RE intermetallic Subject RIV: BM - Solid Matter Physics ; Magnetism

  20. Heat wave generates questions about Ontario's generation capacity

    International Nuclear Information System (INIS)

    Horne, D.

    2005-01-01

    Concerns regarding Ontario's power generation capacity were raised following a major blackout which occurred in August 2003. Power demand reached 26,170 MW during the weeks leading to the blackout, forcing the Independent Electricity System Operator (IESO) to ask residents to reduce electricity use during the day. The grid operator had also issued a forecast that Toronto could face rolling blackouts during times of heavy power demand. Ontario power consumption records were set in June and July of 2003 due to a heat wave, with hourly demand exceeding 25,000 MW on 53 occasions. Ontario was forced to import up to 3,400 MW (13 per cent of its power needs) from neighbouring provinces and the United States. During that period, the price of power had risen sharply to over 30 cents a kilowatt hour, although household consumers were still charged in the 5 to 10 cent range per kilowatt hour. However, it was noted that taxpayers will eventually bear the cost of importing power. The IESO noted that importing electricity is cheaper than the generation available in Ontario and that it is more economical to import, based on the market clearing price of all generators. In 2004, the IESO purchased 6 per cent of their electricity from the United States. That figure is expected to increase for 2005. Ontario generators produced 26.9 million MWh more in the summer of 2005 than during the same period in 2004 to meet electricity demand levels. It was noted that although importing power presently meets peak demand, the IESO agrees there is a need for new generation within Ontario. In addition to restarting Ontario's Pickering and Bruce nuclear facilities, more than 3,300 MW of new gas-fired generation is under construction or approved, and more than 9,000 MW are in various stages of approval. This paper discussed the effect of high energy costs on industry and Ontario's ability to meet future electricity demand in comparison to neighbouring jurisdictions. Issues regarding grid maintenance

  1. Heat Transfer Characteristics of SiC-coated Heat Pipe for Passive Decay Heat Removal

    International Nuclear Information System (INIS)

    Kim, Kyung Mo; Kim, In Guk; Jeong, Yeong Shin; Bang, In Cheol

    2014-01-01

    The main concern with the Fukushima accident was the failure of active and passive core cooling systems. The main function of existing passive decay heat removal systems is feeding additional coolant to the reactor core. Thus, an established emergency core cooling system (ECCS) cannot operate properly because of impossible depressurization under the station blackout (SBO) condition. Therefore, a new concept for passive decay heat removal system is required. In this study, an innovative hybrid control rod concept is considered for passive in-core decay heat removal that differs from the existing direct vessel injection core cooling system and passive auxiliary feedwater system (PAFS). The heat transfer between the evaporator and condenser sections occurs by phase change of the working fluid and capillary action induced by wick structures installed on the inner wall of the heat pipe. In this study, a hybrid control rod is developed to take the roles of both neutron absorption and heat removal by combining the functions of a heat pipe and control rod. Previous studies on enhancing the heat removal capacity of heat pipes used nanofluids, self-rewetting fluids, various wick structures and condensers. Many studies have examined the thermal performances of heat pipes using various nanofluids. They concluded that the enhanced thermal performance of the heat pipe using nanofluids is due to nanoparticle deposition on the wick structures. Thus, the wick structure of heat pipes has been modified by nanoparticle deposition to enhance the heat removal capacity. However, previous studies used relatively small heat pipes and narrow ranges of heat loads. The environment of a nuclear reactor is very specific, and the decay heat produced by fission products after shutdown is relatively large. Thus, this study tested a large-scale heat pipe over a wide range of power. The concept of a hybrid heat pipe for an advanced in-core decay heat removal system was introduced for complete

  2. Heat Transfer Characteristics of SiC-coated Heat Pipe for Passive Decay Heat Removal

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Kyung Mo; Kim, In Guk; Jeong, Yeong Shin; Bang, In Cheol [Ulsan National Institute of Science and Technology, Ulsan (Korea, Republic of)

    2014-10-15

    The main concern with the Fukushima accident was the failure of active and passive core cooling systems. The main function of existing passive decay heat removal systems is feeding additional coolant to the reactor core. Thus, an established emergency core cooling system (ECCS) cannot operate properly because of impossible depressurization under the station blackout (SBO) condition. Therefore, a new concept for passive decay heat removal system is required. In this study, an innovative hybrid control rod concept is considered for passive in-core decay heat removal that differs from the existing direct vessel injection core cooling system and passive auxiliary feedwater system (PAFS). The heat transfer between the evaporator and condenser sections occurs by phase change of the working fluid and capillary action induced by wick structures installed on the inner wall of the heat pipe. In this study, a hybrid control rod is developed to take the roles of both neutron absorption and heat removal by combining the functions of a heat pipe and control rod. Previous studies on enhancing the heat removal capacity of heat pipes used nanofluids, self-rewetting fluids, various wick structures and condensers. Many studies have examined the thermal performances of heat pipes using various nanofluids. They concluded that the enhanced thermal performance of the heat pipe using nanofluids is due to nanoparticle deposition on the wick structures. Thus, the wick structure of heat pipes has been modified by nanoparticle deposition to enhance the heat removal capacity. However, previous studies used relatively small heat pipes and narrow ranges of heat loads. The environment of a nuclear reactor is very specific, and the decay heat produced by fission products after shutdown is relatively large. Thus, this study tested a large-scale heat pipe over a wide range of power. The concept of a hybrid heat pipe for an advanced in-core decay heat removal system was introduced for complete

  3. Analysis of heat capacity and Mössbauer data for LuZnSn2 compound

    Directory of Open Access Journals (Sweden)

    Łątka Kazimierz

    2015-03-01

    Full Text Available New analysis of heat capacity data is presented for LuZnSn2 compound that takes into account anharmonic effects together with the existence of Einstein modes. 119mSn Mössbauer spectroscopy was used to monitor the hyperfine parameters at the two crystallographically inequivalent Sn sites in the studied compound. The problem of non-unique mathematical resonance spectrum description and the problem how to choose physically meaningful set of hyperfine parameters will be thoroughly discussed. Measured quadrupole interaction constants by 119mSn Mössbauer spectroscopy give estimations for Vzz component of electric field gradient tensor at both Sn sites in LuZnSn2.

  4. High-temperature process heat reactor with solid coolant and radiant heat exchange

    International Nuclear Information System (INIS)

    Alekseev, A.M.; Bulkin, Yu.M.; Vasil'ev, S.I.

    1984-01-01

    The high temperature graphite reactor with the solid coolant in which heat transfer is realized by radiant heat exchange is described. Neutron-physical and thermal-technological features of the reactor are considered. The reactor vessel is made of sheet carbon steel in the form of a sealed rectangular annular box. The moderator is a set of graphite blocks mounted as rows of arched laying Between the moderator rows the solid coolant annular layings made of graphite blocks with high temperature nuclear fuel in the form of coated microparticles are placed. The coolant layings are mounted onto ring movable platforms, the continuous rotation of which is realizod by special electric drives. Each part of the graphite coolant laying consecutively passes through the reactor core neutron cut-off zones and technological zone. In the core the graphite is heated up to the temperature of 1350 deg C sufficient for effective radiant heat transfer. In the neutron cut-off zone the chain reaction and further graphite heating are stopped. In the technological zone the graphite transfers the accumulated heat to the walls of technological channels in which the working medium moves. The described reactor is supposed to be used in nuclear-chemical complex for ammonia production by the method of methane steam catalytic conversion

  5. Does visual short-term memory have a high-capacity stage?

    Science.gov (United States)

    Matsukura, Michi; Hollingworth, Andrew

    2011-12-01

    Visual short-term memory (VSTM) has long been considered a durable, limited-capacity system for the brief retention of visual information. However, a recent work by Sligte et al. (Plos One 3:e1699, 2008) reported that, relatively early after the removal of a memory array, a cue allowed participants to access a fragile, high-capacity stage of VSTM that is distinct from iconic memory. In the present study, we examined whether this stage division is warranted by attempting to corroborate the existence of an early, high-capacity form of VSTM. The results of four experiments did not support Sligte et al.'s claim, since we did not obtain evidence for VSTM retention that exceeded traditional estimates of capacity. However, performance approaching that observed in Sligte et al. can be achieved through extensive practice, providing a clear explanation for their findings. Our evidence favors the standard view of VSTM as a limited-capacity system that maintains a few object representations in a relatively durable form.

  6. 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

  7. Influence of water–air ratio on the heat transfer and creep life of a high pressure gas turbine blade

    International Nuclear Information System (INIS)

    Eshati, S.; Abu, A.; Laskaridis, P.; Khan, F.

    2013-01-01

    An analytical model to investigate the influence of Water–Air Ratio (WAR) on turbine blade heat transfer and cooling processes (and thus the blade creep life) of industrial gas turbines is presented. The effects of WAR are emphasised for the modelling of the gas properties and the subsequent heat transfer process. The approach considers convective/film cooling and includes the influence of a thermal barrier coating. In addition, the approach is based on the thermodynamic outputs of a gas turbine performance simulation, heat transfer model, as well as a method that accounts for the changes in the properties of moist air as a function of WAR. For a given off-design point, the variation of WAR (0.0–0.10) was investigated using the heat transfer model. Results showed that with increasing WAR the blade inlet coolant temperature reduced along the blade span. The blade metal temperature at each section was reduced as WAR increased, which in turn increased the blade creep life. The increase in WAR increased the specific heat of the coolant and increased the heat transfer capacity of the coolant air flow. The model can be implemented by using the thermodynamic cycle of the engine, without knowing the turbine cooling details in the conceptual design stage. Also, this generic method assists the end user to understand the effect of operating conditions and design parameter on the creep life of a high pressure turbine blade. -- Highlights: • The influence of WAR on gas turbine blade heat transfer and creep life is examined. • Coolant specific heat capacity is the key property affected by changes in WAR. • Increase in WAR reduces the coolant and metal temperature along the blade span. • Creep life increases with increase in WAR even if ambient temperature is increased

  8. Developing Leadership Capacity in Others: An Examination of High School Principals' Personal Capacities for Fostering Leadership

    Science.gov (United States)

    Huggins, Kristin Shawn; Klar, Hans W.; Hammonds, Hattie L.; Buskey, Frederick C.

    2017-01-01

    In this multisite case study, we examine the personal capacities of six high school principals who have developed the leadership capacities of other leaders in their respective schools. Participants were purposefully selected by two teams of researchers in two states of the United States, one on the east coast and one on the west coast, who…

  9. Effect of Al_2O_3 nanoparticle dispersion on the specific heat capacity of a eutectic binary nitrate salt for solar power applications

    International Nuclear Information System (INIS)

    Hu, Yanwei; He, Yurong; Zhang, Zhenduo; Wen, Dongsheng

    2017-01-01

    Highlights: • Stable binary nitrate eutectic salt based Al_2O_3 nanofluids were prepared. • A maximum enhancement of 8.3% on c_p was obtained at 2.0 wt.% nanoparticles. • MD simulation results show good agreement with experimental data. • The change in Coulombic energy contributed to most of the large change in c_p. - Abstract: Molten salts can be used as heat transfer fluids or thermal storage materials in a concentrated solar power plant. Improving the thermal properties can influence the utilization efficiency of solar energy. In this study, the effect of doping eutectic binary salt solvent with Al_2O_3 nanoparticles on its specific heat capacity (c_p) was investigated. The effects of the mass fraction of nanoparticles on the c_p of the composite nanofluid were analyzed, using both differential scanning calorimetry measurements and molecular dynamics simulations. The specific heat capacity of the nanocomposites was enhanced by increasing the nanoparticle concentration. The maximum enhancement was found to be 8.3%, at a nanoparticle concentration of 2.0%. A scanning electron microscope was used to analyze the material morphology. It was observed that special nanostructures were formed and the specific heat capacity of the nanocomposites was enhanced by increasing the quantity of nanostructures. Simulation results of c_p agreed well with the experimental data, and the potential energy and interaction energy in the system were analyzed. The change in Coulombic energy contributed to most of the large change in c_p, which explains the discrepancy in values between conventional nanofluids and molten salt-based nanofluids.

  10. OTDM Networking for Short Range High-Capacity Highly Dynamic Networks

    DEFF Research Database (Denmark)

    Medhin, Ashenafi Kiros

    This PhD thesis aims at investigating the possibility of designing energy-efficient high-capacity (up to Tbit/s) optical network scenarios, leveraging on the effect of collective switching of many bits simultaneously, as is inherent in high bit rate serial optical data signals. The focus...... is on short range highly dynamic networks, catering to data center needs. The investigation concerns optical network scenarios, and experimental implementations of high bit rate serial data packet generation and reception, scalable optical packet labeling, simple optical label extraction and stable ultra...

  11. Heat capacity of a white-eucalyptus biocarbon template for SiC/Si ecoceramics

    Science.gov (United States)

    Parfen'eva, L. S.; Smirnov, B. I.; Smirnova, I. A.; Wlosewicz, D.; Misiorek, H.; Jezowski, A.; Mucha, J.; de Arellano-Lopez, A. R.; Martinez-Fernandez, J.; Varela-Feria, F. M.; Krivchikov, A. I.

    2006-11-01

    The heat capacity C p of a biocarbon template based on white eucalyptus wood is measured at a constant pressure in the temperature range T = 3.5 300 K. The phonon mean free path l for a white-eucalyptus biocarbon template is calculated from the measured dependence C p (T) and data available in the literature on the phonon thermal conductivity and velocity of sound. It is established that, in the range 100 300 K, the phonon mean free path l is nearly constant and equal to ˜13 Å. This value is close to the smallest size of graphite-like crystallites (˜12 Å), which was derived earlier from x-ray diffraction data for a quasi-amorphous biocarbon template.

  12. Thermodynamic comparision of R744/R600a and R744/R600 used in mid-high temperature heat pump system

    Directory of Open Access Journals (Sweden)

    Fan Xiao-Wei

    2014-01-01

    Full Text Available The mid-high temperature heat pump provides hot water at a relatively high temperature using some industrial waste heat as its source. Now, the main refrigerants in this application are CFC114, HCFC123, and HCFC142b, etc., which are scheduled to be phased out due to their high ozone depletion potential and global warmth potential. Some studies have been conducted to find an eco-friendly alternative. In this paper, the natural non-azeotropic mixtures R744/R600a and R744/R600 are analyzed as alternatives. The performance of the heat pump system using new mixture is discussed and compared with those with CFC114, HCFC123, and HCFC142b. Under the given operating conditions, the maximum heating COP should occur at the mass fractions of 18/82 for R744/R600a and 10/90 for R744/R600. Both of their COP are higher than those with the refrigerants of CFC114, HCFC123, and HCFC142b. The COP and volumetric heating capacity of the system with R744/R600a are superior to those with R744/R600.

  13. Geothermal properties of Swiss Molasse Basin (depth range 0-500 m) - 2006 upgrade of the thermal conductivity, heat capacity, rock density and porosity data base

    International Nuclear Information System (INIS)

    Leu, W.; Megel, T.; Schaerli, U.

    2006-01-01

    The main aim of this project is the preparation of a specific data base of geothermal properties for typical rocks of the Swiss Molasse Basin (depth interval 0-500 m). The project includes the development of a new laboratory tool for efficient heat capacity measurements on rock samples, numerous new measurements of geothermal rock properties in the laboratory and calculation of such data from geophysical borehole logs. In the geographical area under review, 282 rock samples, mainly from deep boreholes, were analyzed with the successfully calibrated new heat capacity device and conventional thermal conductivity measuring techniques (cuttings and cores). Based on sonic and density log data from exploration wells, 374 additional data points were generated. This new data base characterizes in detail the six main lithological rock types in the three Molasse groups OSM, OMM and USM within the Swiss Plateau Molasse. The statistical evaluation of all data illustrates the regional variation of the petrophysical and geothermal parameters. For most data groups bulk rock density and thermal conductivity increase, whereas heat capacity decreases in the direction towards the Alpine front. Thermal conductivity shows a distinct increase with depth. Based on this new information and with the aid of the evaluation software tool SwEWS, the costs of planned geothermal installations can be optimized thanks to more precise heat extraction simulations with existing software packages like COSOND, TRNSYS, EWS or WPcalc. (author)

  14. APS high heat load monochromator

    International Nuclear Information System (INIS)

    Lee, W.K.; Mills, D.

    1993-02-01

    This document contains the design specifications of the APS high heat load (HHL) monochromator and associated accessories as of February 1993. It should be noted that work is continuing on many parts of the monochromator including the mechanical design, crystal cooling designs, etc. Where appropriate, we have tried to add supporting documentation, references to published papers, and calculations from which we based our decisions. The underlying philosophy behind performance specifications of this monochromator was to fabricate a device that would be useful to as many APS users as possible, that is, the design should be as generic as possible. In other words, we believe that this design will be capable of operating on both bending magnet and ID beamlines (with the appropriate changes to the cooling and crystals) with both flat and inclined crystal geometries and with a variety of coolants. It was strongly felt that this monochromator should have good energy scanning capabilities over the classical energy range of about 4 to 20 keywith Si (111) crystals. For this reason, a design incorporating one rotation stage to drive both the first and second crystals was considered most promising. Separate rotary stages for the first and second crystals can sometimes provide more flexibility in their capacities to carry heavy loads (for heavily cooled first crystals or sagittal benders of second crystals), but their tuning capabilities were considered inferior to the single axis approach

  15. Durability of a fin-tube latent heat storage using high density polyethylene as PCM

    Science.gov (United States)

    Zauner, Christoph; Hengstberger, Florian; Etzel, Mark; Lager, Daniel; Hofmann, Rene; Walter, Heimo

    2017-10-01

    Polymers have rarely been used as storage materials in latent heat storages up to now. Thus, we systematically screened all polymers available on a large-scale, selected promising ones based on their theoretical properties and experimentally tested more than 50 candidates. We found that polyethylene, polyoxymethylene and polyamides are promising even as recycled material. Especially high density polyethylene (HDPE) turned out to be suitable as was shown by detailed thermophysical characterization including more than 1000 heating and cooling cycles for INEOS Rigidex HD6070EA. We built a storage with 170 kg HDPE and a total mass of 600 kg based on a fin-tube heat exchanger and characterized its energy capacity, power characteristics and temperature profiles using a thermal oil test rig. In total we performed 30 melting and crystallization cycles where the whole storage was above 100 °C for more than 140 hours. After usage we examined the interior of the storage by cutting it into various pieces. A thin layer of degradation was observed on the surfaces of the PCM which is most likely related to thermo-oxidative degeneration of HDPE. However, the bulk of the PCM is still intact as well as the heat exchanger itself.

  16. Identifying Changes in the Probability of High Temperature, High Humidity Heat Wave Events

    Science.gov (United States)

    Ballard, T.; Diffenbaugh, N. S.

    2016-12-01

    Understanding how heat waves will respond to climate change is critical for adequate planning and adaptation. While temperature is the primary determinant of heat wave severity, humidity has been shown to play a key role in heat wave intensity with direct links to human health and safety. Here we investigate the individual contributions of temperature and specific humidity to extreme heat wave conditions in recent decades. Using global NCEP-DOE Reanalysis II daily data, we identify regional variability in the joint probability distribution of humidity and temperature. We also identify a statistically significant positive trend in humidity over the eastern U.S. during heat wave events, leading to an increased probability of high humidity, high temperature events. The extent to which we can expect this trend to continue under climate change is complicated due to variability between CMIP5 models, in particular among projections of humidity. However, our results support the notion that heat wave dynamics are characterized by more than high temperatures alone, and understanding and quantifying the various components of the heat wave system is crucial for forecasting future impacts.

  17. Evaporation and condensation devices for passive heat removal systems in nuclear power engineering

    International Nuclear Information System (INIS)

    Gershuni, A.N.; Pis'mennyj, E.N.; Nishchik, A.P.

    2016-01-01

    The paper justifies advantages of evaporation and condensation heat transfer devices as means of passive heat removal and thermal shielding in nuclear power engineering. The main thermophysical factors that limit heat transfer capacity of evaporation and condensation systems have been examined in the research. The results of experimental studies of heat engineering properties of elongated (8-m) vertically oriented evaporation and condensation devices (two-phase thermosyphons), which showed a high enough heat transfer capacity, as well as stability and reliability both in steady state and in start-up modes, are provided. The paper presents the examples of schematic designs of evaporation and condensation systems for passive heat removal and thermal shielding in application to nuclear power equipment

  18. In-volume heating using high-power laser diodes

    NARCIS (Netherlands)

    Denisenkov, V.S.; Kiyko, V.V.; Vdovin, G.V.

    2015-01-01

    High-power lasers are useful instruments suitable for applications in various fields; the most common industrial applications include cutting and welding. We propose a new application of high-power laser diodes as in-bulk heating source for food industry. Current heating processes use surface

  19. Reversible anionic redox chemistry in high-capacity layered-oxide electrodes

    Science.gov (United States)

    Sathiya, M.; Rousse, G.; Ramesha, K.; Laisa, C. P.; Vezin, H.; Sougrati, M. T.; Doublet, M.-L.; Foix, D.; Gonbeau, D.; Walker, W.; Prakash, A. S.; Ben Hassine, M.; Dupont, L.; Tarascon, J.-M.

    2013-09-01

    Li-ion batteries have contributed to the commercial success of portable electronics and may soon dominate the electric transportation market provided that major scientific advances including new materials and concepts are developed. Classical positive electrodes for Li-ion technology operate mainly through an insertion-deinsertion redox process involving cationic species. However, this mechanism is insufficient to account for the high capacities exhibited by the new generation of Li-rich (Li1+xNiyCozMn(1-x-y-z)O2) layered oxides that present unusual Li reactivity. In an attempt to overcome both the inherent composition and the structural complexity of this class of oxides, we have designed structurally related Li2Ru1-ySnyO3 materials that have a single redox cation and exhibit sustainable reversible capacities as high as 230 mA h g-1. Moreover, they present good cycling behaviour with no signs of voltage decay and a small irreversible capacity. We also unambiguously show, on the basis of an arsenal of characterization techniques, that the reactivity of these high-capacity materials towards Li entails cumulative cationic (Mn+→M(n+1)+) and anionic (O2-→O22-) reversible redox processes, owing to the d-sp hybridization associated with a reductive coupling mechanism. Because Li2MO3 is a large family of compounds, this study opens the door to the exploration of a vast number of high-capacity materials.

  20. Heat Exchangers for Utilization of the Heat of High-Temperature Geothermal Brines

    Science.gov (United States)

    Alkhasov, A. B.; Alkhasova, D. A.

    2018-03-01

    The basic component of two-circuit geothermal systems is the heat exchanger. When used in geothermal power systems, conventional shell-and-tube and plate heat exchangers cause problems related to the cleaning of the latter from salt-deposition and corrosion products. Their lifetime does not exceed, as a rule, 1 year. To utilize the heat of high-temperature geothermal brines, a heat exchanger of the "tube-in-tube" type is proposed. A heat exchanger of this design has been operated for several years in Ternair geothermal steam field; in this heat exchanger, the thermal potential of the saline thermal water is transferred to the fresh water of the secondary circuit of the heating system for apartment houses. The reduction in the weight and size characteristics of the heat exchangers is a topical problem that can be solved with the help of heat transfer enhancers. To enhance the heat transfer process in the heat exchanger, longitudinal ribbing of the heat exchange surface is proposed. The increase in the heat exchange surface from the heat carrier side by ribbing results in an increase in the amount of the heat transferred from the heating agent. The heat exchanger is easy to manufacture and is assembled out of components comprised of two concentrically positioned tubes of a definite length, 3-6 m, serially connected with each other. The method for calculation of the impact of the number and the size of the longitudinal ribs on the heat transfer in the well heat exchanger is presented and a criterion for the selection of the optimal number and design parameters of the ribs is formulated. To prevent the corrosion and salt deposition in the heat exchanger, the use of an effective OEDFK (oxyethylidenediphosphonic acid) agent is proposed. This agent has a long-lasting corrosion-inhibiting and antiscaling effect, which is explained by the formation of a strongly adhesive chelate layer difficult to wash off the surface. The passivating OEDFK layer is restored by periodical

  1. Economic feasibility of district heating delivery from industrial excess heat: A case study of a Swedish petrochemical cluster

    International Nuclear Information System (INIS)

    Morandin, Matteo; Hackl, Roman; Harvey, Simon

    2014-01-01

    The present work discusses the potential and the economic feasibility of DH (district heating) delivery using industrial excess heat from a petrochemical cluster at the Swedish West Coast. Pinch Analysis was used for estimating the DH capacity targets and for estimating the cost of heat exchanger installation. A discounted cash flow rate of return of 10% was used as a criterion for identifying the minimum yearly DH delivery that should be guaranteed for a given DH capacity at different DH sales prices. The study was conducted for the current scenario in which no heat recovery is achieved between the cluster plants and for a possible future scenario in which 50% of the fuel currently used for heating purposes is saved by increasing the heat recovery at the site. The competition between excess heat export and local energy efficiency measures is also discussed in terms of CO 2 emission consequences. The maximum capacity of DH delivery amounts today to around 235 MW, which reduces to 110 MW in the future scenario of increased site heat recovery. The results of our analysis show that feasible conditions exist that make DH delivery profitable in the entire capacity range. - Highlights: • Pinch Analysis targeting approach and short-cut cost accounting procedure. • Economic analysis for different DH delivery capacities up to maximum targets. • Sensitivity analysis of heat sales prices. • Parallel plants and cluster wide heat collection systems considered. • Competition between cluster internal heat recovery and excess heat export is discussed

  2. High temperature heat pipe experiments in low earth orbit

    International Nuclear Information System (INIS)

    Woloshun, K.; Merrigan, M.A.; Sena, J.T.; Critchley, E.

    1993-01-01

    Although high temperature, liquid metal heat pipe radiators have become a standard component on most high power space power system designs, there is no experimental data on the operation of these heat pipes in a zero gravity or micro-gravity environment. Experiments to benchmark the transient and steady state performance of prototypical heat pipe space radiator elements are in preparation for testing in low earth orbit. It is anticipated that these heat pipes will be tested aborad the Space Shuttle in 1995. Three heat pipes will be tested in a cargo bay Get Away Special (GAS) canister. The heat pipes are SST/potassium, each with a different wick structure; homogeneous, arterial, and annular gap, the heat pipes have been designed, fabricated, and ground tested. In this paper, the heat pipe designs are specified, and transient and steady-state ground test data are presented

  3. A role for haemolymph oxygen capacity in heat tolerance of eurythermal crabs.

    Directory of Open Access Journals (Sweden)

    Folco eGiomi

    2013-05-01

    Full Text Available Heat tolerance in aquatic ectotherms is constrained by a mismatch, occurring at high temperatures, between oxygen delivery and demand which compromises the maintenance of aerobic scope. The present study analyses how the wide thermal tolerance range of an eurythermal model species, the green crab Carcinus maenas is supported and limited by its ability to sustain efficient oxygen transport to tissues. Similar to other eurytherms, C. maenas sustains naturally occurring acute warming events through the integrated response of circulatory and respiratory systems. The response of C. maenas to warming is characterized by two phases. During initial warming, oxygen consumption and heart rate increase while stroke volume and haemolymph oxygen partial pressures decrease. During further warming, dissolved oxygen levels in the venous compartment decrease below the threshold of full haemocyanin oxygen saturation. The progressive release of haemocyanin bound oxygen with further warming follows an exponential pattern, thereby saving energy in oxygen transport and causing an associated leveling off of metabolic rate. According to the concept of oxygen and capacity limited thermal tolerance, this indicates that the thermal tolerance window is widened by the increasing contribution of haemocyanin oxygen transport and associated energy savings in cardiocirculation. Haemocyanin bound oxygen sustains cardiac performance to cover the temperature range experienced by C. maenas in the field. To our knowledge this is the first study providing evidence of a relationship between thermal tolerance and blood (haemolymph oxygen transport in eurythermal invertebrates.

  4. A role for haemolymph oxygen capacity in heat tolerance of eurythermal crabs.

    Science.gov (United States)

    Giomi, Folco; Pörtner, Hans-Otto

    2013-01-01

    Heat tolerance in aquatic ectotherms is constrained by a mismatch, occurring at high temperatures, between oxygen delivery and demand which compromises the maintenance of aerobic scope. The present study analyses how the wide thermal tolerance range of an eurythermal model species, the green crab Carcinus maenas is supported and limited by its ability to sustain efficient oxygen transport to tissues. Similar to other eurytherms, C. maenas sustains naturally occurring acute warming events through the integrated response of circulatory and respiratory systems. The response of C. maenas to warming can be characterized by two phases. During initial warming, oxygen consumption and heart rate increase, while stroke volume and haemolymph oxygen partial pressure decrease. During further warming, dissolved oxygen levels in the venous compartment decrease below the threshold of full haemocyanin oxygen saturation. The progressive release of haemocyanin bound oxygen with further warming follows an exponential pattern, thereby saving energy in oxygen transport and causing an associated leveling off of metabolic rate. According to the concept of oxygen and capacity limited thermal tolerance (OCLTT), this indicates that the thermal tolerance window is widened by the increasing contribution of haemocyanin oxygen transport and associated energy savings in cardiocirculation. Haemocyanin bound oxygen sustains cardiac performance to cover the temperature range experienced by C. maenas in the field. To our knowledge this is the first study providing evidence of a relationship between thermal tolerance and blood (haemolymph) oxygen transport in a eurythermal invertebrate.

  5. Binders and Hosts for High-Capacity Lithium-ion Battery Anodes

    Science.gov (United States)

    Dufficy, Martin Kyle

    Lithium-ion batteries (LIBs) are universal electrochemical energy storage devices that have revolutionized our mobile society. Nonetheless, societal and technological advances drive consumer demand for LIBs with enhanced electrochemical performance, such as higher charge capacity and longer life, compared to conventional LIBs. One method to enhance LIB performance is to replace graphite, the industry standard anode since commercialization of LIBs in 1991, with high-charge capacity materials. Implementing high-capacity anode materials such as tin, silicon, and manganese vanadates, to LIBs presents challenges; Li-insertion is destructive to anode framework, and increasing capacity increases structural strains that pulverize anode materials and results in a short-cycle life. This thesis reports on various methods to extended the cycle life of high-capacity materials. Most of the work is conducted on nano-sized anode materials to reduce Li and electron transport pathway length (facilitating charge-transfer) and reduce strains from volume expansions (preserving anode structure). The first method involves encapsulating tin particles into a graphene-containing carbon nanofiber (CNF) matrix. The composite-CNF matrix houses tin particles to assume strains from tin-volume expansions and produces favorable surface-electrolyte chemistries for stable charge-discharge cycling. Before tin addition, graphene-containing CNFs are produced and assessed as anode materials for LIBs. Graphene addition to CNFs improves electronic and mechanical properties of CNFs. Furthermore, the 2-D nature of graphene provides Li-binding sites to enhance composite-CNF both first-cycle and high-rate capacities > 150% when compared to CNFs in the absence of graphene. With addition of Sn, we vary loadings and thermal production temperature to elucidate structure-composition relationships of tin and graphene-containing CNF electrodes that lead to increased capacity retention. Of note, electrodes containing

  6. Evaluation of dry heat treatment of soft wheat flour for the production of high ratio cakes.

    Science.gov (United States)

    Keppler, S; Bakalis, S; Leadley, C E; Sahi, S S; Fryer, P J

    2018-05-01

    An accurate method to heat treat flour samples has been used to quantify the effects of heat treatment on flour functionality. A variety of analytical methods has been used such as oscillatory rheology, rheomixer, solvent retention capacity tests, and Rapid Visco Analysis (RVA) in water and in aqueous solutions of sucrose, lactic acid, and sodium carbonate. This work supports the hypothesis that heat treatment facilitates the swelling of starch granules at elevated temperature. Results furthermore indicated improved swelling ability and increased interactions of flour polymers (in particular arabinoxylans) of heat treated flour at ambient conditions. The significant denaturation of the proteins was indicated by a lack of gluten network formation after severe heat treatments as shown by rheomixer traces. Results of these analyses were used to develop a possible cake flour specification. A method was developed using response surfaces of heat treated flour samples in the RVA using i) water and ii) 50% sucrose solution. This can uniquely characterise the heat treatment a flour sample has received and to establish a cake flour specification. This approach might be useful for the characterisation of processed samples, rather than by baking cakes. Hence, it may no longer be needed to bake a cake after flour heat treatment to assess the suitability of the flour for high ratio cake production, but 2 types of RVA tests suffice. Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.

  7. Capacity Decline and Characteristics Changes of Lithium-ion Cells with Large Capacity during Trickle Charge at High Temperature

    Science.gov (United States)

    Matsushima, Toshio

    Large-scale 40-Ah Li-ion cells have been developed for use in industrial applications. To contribute to techniques for ascertaining the state of these cells and detecting deterioration during actual use, we produce a cell whose capacity is reduced by trickle charging at high temperature, and we determine the relationship between the cell's properties such as its capacity and charging/discharging characteristics when the capacity is reduced. When the capacity of a Li-ion cell is reduced, the discharge voltage also decreases. We show that the residual capacity is well correlated to the discharge voltage and to the duration of continuous discharge before reaching a fixed end-voltage. We also show that the constant-current constant-voltage charging characteristics are maintained even when the capacity is degraded, and that the constant-current charging time and discharge voltage are closely related to the residual capacity. We confirm that the reaction coefficient of the capacity degradation formula can be calculated from the capacity change characteristics at multiple temperatures, and that an 8°C change in temperature causes the lifetime to decrease by half.

  8. Experimental investigation of moderately high temperature water source heat pump with non-azeotropic refrigerant mixtures

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Shengjun; Wang, Huaixin; Guo, Tao [Department of Thermal Energy and Refrigeration Engineering, School of Mechanical Engineering, Tianjin University, Tianjin 300072 (China)

    2010-05-15

    Experimental investigations were carried out on non-azeotropic refrigerant mixtures, named M1A (mass fraction of 20%R152a and 80%R245fa), M1B (mass fraction of 37% R152a and 63%R245fa) and M1C (mass fraction of 50%R152a and 50%R245fa), based on a water-to-water heat pump system in the condensing temperature range of 70-90 C with a cycle temperature lift of 45 C. Performance of R245fa was tested for comparison. Unfair factors in experimental comparative evaluation research with the same apparatus were identified and corrected. Experimental cycle performance of the mixtures were tested and compared with improved experimental assessment methodology. The results show that all of the mixtures deliver higher discharge temperature, higher heating capacity, higher COP and higher {epsilon}{sub h,c} than R245fa. M1B presents the most excellent cycle performance and is recommended as working fluid for moderate/high temperature heat pump. (author)

  9. Effect of radiation heat transfer on the performance of high temperature heat exchanger, (2)

    International Nuclear Information System (INIS)

    Yamada, Yukio; Mori, Yasuo; Hijikata, Kunio.

    1977-01-01

    In high temperature helium gas-cooled reactors, the nuclear energy can be utilized effectively, and the safety is excellent as compared with conventional reactors. They are advantageous also in view of environmental problems. In this report, the high temperature heat exchanger used for heating steam with the helium from a high temperature gas reactor is modeled, and the case that radiating gas flow between parallel plates is considered. Analysis was made on the case of one channel and constant heat flux and on the model for a counter-flow type heat exchanger with two channels, and the effect of radiation on the heat transfer in laminar flow and turbulent flow regions was clarified theoretically. The basic equations, the method of approximate solution and the results of calculation are explained. When one dimensional radiation was considered, the representative temperature Tr regarding fluid radiation was introduced, and its relation to mean mixing temperature Tm was determined. It was clarified that the large error in the result did not arise even if Tr was taken equally to Tm, especially in case of turbulent flow. The error was practically negligible when the rate of forced convection heat transfer in case of radiating medium flow was taken same as that in the case without radiation. (Kako, I.)

  10. Completion of a high efficiency ultralarge capacity three-phase transformer

    International Nuclear Information System (INIS)

    Maejima, Masaaki; Maruyama, Katsuya; Fukuda, Teruo.

    1986-01-01

    As for the boosting transformers for thermal and nuclear power stations, at present the ultralarge capacity transformers of 1000 - 1200 MVA class are the main, and particularly in nuclear power, accompanying the development of improved type BWRs and the rise of system stability, there is the tendency toward further large capacity and large size. Consequently, reflecting the recent rise of energy cost, the demand of energy conservation and the reduction of required sites heightened largely as well as the high reliability. In order to meet these demands, Hitachi Ltd. has established the technology of changing to iron machines such as ultralarge iron cores and ultralarge capacity undivided disk windings using the latest design and manufacture techniques were applied to the 525 kV, 1200 MVA transformer for No.4 plant in Fukushima No.2 Nuclear Power Station, Tokyo Electric Power Co., Inc., thus a three-phase transformer of the highest level, high efficiency and ultralarge capacity was completed. In this paper, the outline of this transformer and the test for verifying its reliability are described. The technical change of large capacity three-phase transformers, the specifications, construction, manufacture, reliability test and the effect of modification of this transformer, and the expansion of application to the next generation ultralarge capacity transformers are reported. (Kako, I.)

  11. Consistency in thermophysical properties: enthalpy, heat capacity, thermal conductivity and thermal diffusivity of solid UO2

    International Nuclear Information System (INIS)

    Fink, J.K.; Chasanov, M.G.; Leibowitz, L.

    Equations have been derived for the enthalpy, heat capacity, thermal conductivity, and thermal diffusivity of UO 2 . In selection of these equations, we considered the traditional criterion of lowest relative standard deviation between experimental data and the function chosen to fit these data as well as consistency between the thermophysical properties. In the latter case, we considered consistency in (1) thermodynamic relations among properties, (2) the choice of physical phenomena on which to base the theoretical formulation of the equations, and (3) the existence and temperature of phase transitions

  12. Apparent and standard molar volumes and heat capacities of aqueous Ni(ClO4)2 from 25 to 85oC

    International Nuclear Information System (INIS)

    Pan, P.; Campbell, A.B.

    1997-01-01

    Apparent molar heat capacities and volumes of aqueous Ni(ClO 4 ) 2 were measured from 25 to 85 o C over a concentration range of 0.02 to 0.8 mol-kg -1 using a Picker flow microcalorimeter and a Picker vibrating-tube densimeter. An extended Debye-Huckel equation was fitted to the experimental data to obtain expressions for the apparent molar properties as functions of ionic strength for Ni(ClO 4 ) 2 (aq). The standard-state partial molar properties for Ni(ClO 4 ) 2 (aq) in the temperature range 25 to 85 o C were obtained and can be expressed by empirical equations. The standard partial molar heat capacities and volumes for Ni 2+ (aq) from 25 to 86 o C were obtained by using the additivity rule and data for ClO - 4 (aq) in the literature. These values were extrapolated to 300 o C by employing the Helgeson-Kirkham-Flower (HKF) equations, amended to include a standard-state correction term. (author)

  13. Colloidal silica films for high-capacity DNA arrays

    Science.gov (United States)

    Glazer, Marc Irving

    The human genome project has greatly expanded the amount of genetic information available to researchers, but before this vast new source of data can be fully utilized, techniques for rapid, large-scale analysis of DNA and RNA must continue to develop. DNA arrays have emerged as a powerful new technology for analyzing genomic samples in a highly parallel format. The detection sensitivity of these arrays is dependent on the quantity and density of immobilized probe molecules. We have investigated substrates with a porous, "three-dimensional" surface layer as a means of increasing the surface area available for the synthesis of oligonucleotide probes, thereby increasing the number of available probes and the amount of detectable bound target. Porous colloidal silica films were created by two techniques. In the first approach, films were deposited by spin-coating silica colloid suspensions onto flat glass substrates, with the pores being formed by the natural voids between the solid particles (typically 23nm pores, 35% porosity). In the second approach, latex particles were co-deposited with the silica and then pyrolyzed, creating films with larger pores (36 nm), higher porosity (65%), and higher surface area. For 0.3 mum films, enhancements of eight to ten-fold and 12- to 14-fold were achieved with the pure silica films and the films "templated" with polymer latex, respectively. In gene expression assays for up to 7,000 genes using complex biological samples, the high-capacity films provided enhanced signals and performed equivalently or better than planar glass on all other functional measures, confirming that colloidal silica films are a promising platform for high-capacity DNA arrays. We have also investigated the kinetics of hybridization on planar glass and high-capacity substrates. Adsorption on planar arrays is similar to ideal Langmuir-type adsorption, although with an "overshoot" at high solution concentration. Hybridization on high-capacity films is

  14. Thermochemical heat storage for high temperature applications. A review

    Energy Technology Data Exchange (ETDEWEB)

    Felderhoff, Michael [Max-Planck-Institut fuer Kohlenforschung, Muelheim an der Ruhr (Germany); Urbanczyk, Robert; Peil, Stefan [Institut fuer Energie- und Umwelttechnik e.V. (IUTA), Duisburg (Germany)

    2013-07-01

    Heat storage for high temperature applications can be performed by several heat storage techniques. Very promising heat storage methods are based on thermochemical gas solid reactions. Most known systems are metal oxide/steam (metal hydroxides), carbon dioxide (metal carbonates), and metal/hydrogen (metal hydrides) systems. These heat storage materials posses high gravimetric and volumetric heat storage densities and because of separation of the reaction products and their storage in different locations heat losses can be avoided. The reported volumetric heat storage densities are 615, 1340 and 1513 [ kWh m{sup -3}] for calcium hydroxide Ca(OH){sub 2}, calcium carbonate CaCO{sub 3} and magnesium iron hydride Mg{sub 2}FeH{sub 6} respectively. Additional demands for gas storage decrease the heat storage density, but metal hydride systems can use available hydrogen storage possibilities for example caverns, pipelines and chemical plants. (orig.)

  15. High rate capacity nanocomposite lanthanum oxide coated lithium zinc titanate anode for rechargeable lithium-ion battery

    International Nuclear Information System (INIS)

    Tang, Haoqing; Zan, Lingxing; Zhu, Jiangtao; Ma, Yiheng; Zhao, Naiqin; Tang, Zhiyuan

    2016-01-01

    Lithium zinc titanate (Li_2ZnTi_3O_8) is an important titanium material of promising candidates for anode materials with superior electrochemical performance and thus has attracted extensive attention. Herein, high capacity, stable Li_2ZnTi_3O_8/La_2O_3 nanocomposite for lithium-ion battery anode is prepared by a facile strategy. Compared to unmodified Li_2ZnTi_3O_8, the Li_2ZnTi_3O_8/La_2O_3 electrode display a high specific capacity of 188.6 mAh g"−"1 and remain as high as 147.7 mAh g"−"1 after 100 cycles at 2.0 A g"−"1. Moreover, a reversible capacity of 76.3 mAh g"−"1 can be obtained after 1000 cycles at 2.0 A g"−"1 and the retention is 42.7% for Li_2ZnTi_3O_8/La_2O_3, which is much higher than un-coated Li_2ZnTi_3O_8. The superior lithium storage performances of the Li_2ZnTi_3O_8/La_2O_3 can be ascribed to the stable layer of protection, small particle size and large surface area. Cyclic voltammograms result reveals that the La_2O_3 coating layer reduces the polarization and improves the electrochemical activity of anode. - Highlights: • Nano layer La_2O_3 coated Li_2ZnTi_3O_8 particles have been prepared via a suspension mixing process followed by heat treatment. • Coated Li_2ZnTi_3O_8 has enhanced high rate capability, cyclic stability and long lifespan performance. • Electrochemical properties were tested in a charge/discharge voltage range of 3.0–0.05 V (vs. Li/Li"+).

  16. Efficient conversion of sand to nano-silicon and its energetic Si-C composite anode design for high volumetric capacity lithium-ion battery

    Science.gov (United States)

    Furquan, Mohammad; Raj Khatribail, Anish; Vijayalakshmi, Savithri; Mitra, Sagar

    2018-04-01

    Silicon is an attractive anode material for Li-ion cells, which can provide energy density 30% higher than any of the today's commercial Li-ion cells. In the current study, environmentally benign, high abundant, and low cost sand (SiO2) source has been used to prepare nano-silicon via scalable metallothermic reduction method using micro wave heating. In this research, we have developed and optimized a method to synthesis high purity nano silicon powder that takes only 5 min microwave heating of sand and magnesium mixture at 800 °C. Carbon coated nano-silicon electrode material is prepared by a unique method of coating, polymerization and finally in-situ carbonization of furfuryl alcohol on to the high purity nano-silicon. The electrochemical performance of a half cell using the carbon coated high purity Si is showed a stable capacity of 1500 mAh g-1 at 6 A g-1 for over 200 cycles. A full cell is fabricated using lithium cobalt oxide having thickness ≈56 μm as cathode and carbon coated silicon thin anode of thickness ≈9 μm. The fabricated full cell of compact size exhibits excellent volumetric capacity retention of 1649 mAh cm-3 at 0.5 C rate (C = 4200 mAh g-1) and extended cycle life (600 cycles). The full cell is demonstrated on an LED lantern and LED display board.

  17. System constitution of plasma high frequency heating device and element equipment

    International Nuclear Information System (INIS)

    Nagashima, Takashi

    1988-01-01

    On the high frequency heating device used for nuclear fusion experiment, the system constitution and the main items of development for the element equipment are described. As for the high frequency heating device, large technical progress was observed in the past 10 years as the second stage heating for tokamaks and one of the main means of current drive. At present, three frequency zones are regarded as promising for plasma high frequency heating in large nuclear fusion devices, and the experiment of 10 MW class is in progress at JT-60, JET and so on. There are electron cyclotron heating, lower hybrid resonance frequency heating and ion cyclotron range of frquency heating. The basic constitution of these heating devices includes a high frequency source, a transmission system, a connection system, and a common system for control, cooling, record and others. The ECH device using gyrotrons of several tens GHz, the LHRF heating device using large power klystrons up to several GHz and the ICRF heating device up to 200 MHz are briefly explained. The main element equipments composing the high frequency heating systems of several tens MW are discussed. (Kako, I.)

  18. The heat-capacity of ilmenite and phase equilibria in the system Fe-T-O

    Science.gov (United States)

    Anovitz, Lawrence M.; Treiman, A.H.; Essene, E.J.; Hemingway, B.S.; Westrum, E.F.; Wall, V.J.; Burriel, R.; Bohlen, S.R.

    1985-01-01

    Low temperature adiabatic calorimetry and high temperature differential scanning calorimetry have been used to measure the heat-capacity of ilmenite (FeTiO3) from 5 to 1000 K. These measurements yield S2980 = 108.9 J/(mol ?? K). Calculations from published experimental data on the reduction of ilmenite yield ??2980(I1) = -1153.9 kJ/(mol ?? K). These new data, combined with available experimental and thermodynamic data for other phases, have been used to calculate phase equilibria in the system Fe-Ti-O. Calculations for the subsystem Ti-O show that extremely low values of f{hook}O2 are necessary to stabilize TiO, the mineral hongquiite reported from the Tao district in China. This mineral may not be TiO, and it should be re-examined for substitution of other elements such as N or C. Consideration of solid-solution models for phases in the system Fe-Ti-O allows derivation of a new thermometer/oxybarometer for assemblages of ferropseudobrookite-pseudobrookitess and hematite-ilmenitess. Preliminary application of this new thermometer/oxybarometer to lunar and terrestrial lavas gives reasonable estimates of oxygen fugacities, but generally yields subsolidus temperatures, suggesting re-equilibration of one or more phases during cooling. ?? 1985.

  19. Performance variations of river water source heat pump system according to heat exchanger capacity variations

    International Nuclear Information System (INIS)

    Park, Seong Ryong; Baik, Young Jin; Lee, Young Soo; Kim, Hee Hwan

    2003-01-01

    The utilization of unused energy is important because it can afford to offer a chance to increase energy efficiency of a heat pump system. One of the promising unused energy sources is river water. It can be used as a heat source in both heating and cooling effectively with its superior features as a secondary working fluids. In this study, the performance of a 5HP heat pump system using river water as a heat source is investigated by both experiment and simulation. According to system simulation results, performance improvement of condenser seems more effective than that of evaporator for better COPH. The serial connection is also preferred among several methods to improve plate type heat exchanger performance. The experimental results show that the hot water of 50∼60 .deg. C can be acquired from water heat source of 5∼9 .deg. C with COPH of 2.7∼3.5

  20. Combined Heat Transfer in High-Porosity High-Temperature Fibrous Insulations: Theory and Experimental Validation

    Science.gov (United States)

    Daryabeigi, Kamran; Cunnington, George R.; Miller, Steve D.; Knutson, Jeffry R.

    2010-01-01

    Combined radiation and conduction heat transfer through various high-temperature, high-porosity, unbonded (loose) fibrous insulations was modeled based on first principles. The diffusion approximation was used for modeling the radiation component of heat transfer in the optically thick insulations. The relevant parameters needed for the heat transfer model were derived from experimental data. Semi-empirical formulations were used to model the solid conduction contribution of heat transfer in fibrous insulations with the relevant parameters inferred from thermal conductivity measurements at cryogenic temperatures in a vacuum. The specific extinction coefficient for radiation heat transfer was obtained from high-temperature steady-state thermal measurements with large temperature gradients maintained across the sample thickness in a vacuum. Standard gas conduction modeling was used in the heat transfer formulation. This heat transfer modeling methodology was applied to silica, two types of alumina, and a zirconia-based fibrous insulation, and to a variation of opacified fibrous insulation (OFI). OFI is a class of insulations manufactured by embedding efficient ceramic opacifiers in various unbonded fibrous insulations to significantly attenuate the radiation component of heat transfer. The heat transfer modeling methodology was validated by comparison with more rigorous analytical solutions and with standard thermal conductivity measurements. The validated heat transfer model is applicable to various densities of these high-porosity insulations as long as the fiber properties are the same (index of refraction, size distribution, orientation, and length). Furthermore, the heat transfer data for these insulations can be obtained at any static pressure in any working gas environment without the need to perform tests in various gases at various pressures.

  1. A solar-thermal energy harvesting scheme: enhanced heat capacity of molten HITEC salt mixed with Sn/SiO(x) core-shell nanoparticles.

    Science.gov (United States)

    Lai, Chih-Chung; Chang, Wen-Chih; Hu, Wen-Liang; Wang, Zhiming M; Lu, Ming-Chang; Chueh, Yu-Lun

    2014-05-07

    We demonstrated enhanced solar-thermal storage by releasing the latent heat of Sn/SiO(x) core-shell nanoparticles (NPs) embedded in a eutectic salt. The microstructures and chemical compositions of Sn/SiO(x) core-shell NPs were characterized. In situ heating XRD provides dynamic crystalline information about the Sn/SiO(x) core-shell NPs during cyclic heating processes. The latent heat of ∼29 J g(-1) for Sn/SiO(x) core-shell NPs was measured, and 30% enhanced heat capacity was achieved from 1.57 to 2.03 J g(-1) K(-1) for the HITEC solar salt without and with, respectively, a mixture of 5% Sn/SiO(x) core-shell NPs. In addition, an endurance cycle test was performed to prove a stable operation in practical applications. The approach provides a method to enhance energy storage in solar-thermal power plants.

  2. Flue gas recovery system for natural gas combined heat and power plant with distributed peak-shaving heat pumps

    International Nuclear Information System (INIS)

    Zhao, Xiling; Fu, Lin; Wang, Xiaoyin; Sun, Tao; Wang, Jingyi; Zhang, Shigang

    2017-01-01

    Highlights: • A flue gas recovery system with distributed peak-shaving heat pumps is proposed. • The system can improve network transmission and distribution capacity. • The system is advantageous in energy saving, emission reduction and economic benefits. - Abstract: District heating systems use distributed heat pump peak-shaving technology to adjust heat in secondary networks of substations. This technology simultaneously adjusts the heat of the secondary network and reduces the return-water temperature of the primary network by using the heat pump principle. When optimized, low temperature return-water is able to recycle more waste heat, thereby further improving the heating efficiency of the system. This paper introduces a flue gas recovery system for a natural gas combined heat and power plant with distributed peak-shaving heat pumps. A pilot system comprising a set of two 9F gas-steam combined cycle-back pressure heating units was used to analyse the system configuration and key parameters. The proposed system improved the network transmission and distribution capacity, increased heating capacity, and reduced heating energy consumption without compromising heating safety issues. As such, the proposed system is advantageous in terms of energy saving, emission reduction, and economic benefits.

  3. Thermophysical data for various transition metals at high temperatures obtained by a submicrosecond-pulse-heating method

    International Nuclear Information System (INIS)

    Seydel, U.; Bauhof, H.; Fucke, W.; Wadle, H.

    1979-01-01

    Thermophysical data for several transition metals are reported including enthalpies, electric resistivities, and specific volumes at the melting transition, and volume expansion coefficients and heat capacities in the liquid phase. Values for the critical temperatures, pressures, and volumes are given for molybdenum and tungsten. All data have been obtained by a submicrosecond-pulse-heating method. (author)

  4. Excess heat capacity of the (Li1?xCax)F1+x liquid solution determined by differential scanning calorimetry and drop calorimetry

    NARCIS (Netherlands)

    Capelli, E.; Benes, O.; Konings, R.J.M.

    2014-01-01

    The work presents the measured heat capacity of the (Li1?xCax)F1+x liquid solution. Four samples with different compositions have been prepared and measured using a Differential Scanning Calorimeter. Since this technique was newly adopted for measuring encapsulated fluoride samples, some

  5. Combined heat and power generation with exhaust-heated two-stage absorption refrigerator. Performance of a pilot installation with a refrigeration capacity of 350 kW; Kraft-Waerme-Kaelte-Kopplung mit Abgas-Beheizter zweistufiger Absorptionskaeltemaschine. Betriebserfahrungen einer Pilotinstallation mit 350 kW Kaelteleistung

    Energy Technology Data Exchange (ETDEWEB)

    Plura, S.; Baumeister, D.; Koeberle, T.; Radspieler, M.; Schweigler, C. [Bayerisches Zentrum fuer Angewandte Energieforschung e.V. (ZAE Bayern), Garching (Germany)

    2007-07-01

    A new system concept for higher efficiency of cogeneration systems is developed in which a cogeneration unit is combined with a two-stage absorption refrigerator, and the waste heat of the cogeneration unit is directly passed on into the regenerator of the absorption refrigerator. The higher temperature level of the waste heat makes it possible to use a two-stage absorption cycle for higher energy efficiency. For simultaneous utilisation of low-temperature heat, the two-stage cycle is combined with a one-stage cycle for additional heat supply at a lower temperature level so that the exhaust of a typical cogeneration unit will be cooled to about 120 degC. At the same time, further waste heat of the cogeneration unit will be transferred to the heat pump via a hot water circuit. This concept with a combined single-stage and two-stage absorption circuit is referred to as a double-effect/single-effect circuit. The new system is used for energy supply in a spa, where the two-stage absorption refrigerator cools the water used for swimming pool cleaning with a refrigerating capacity of 350 kW and provides low-temperature heat for swimming pool heating with a capacity of 700 kW. (orig.)

  6. The heat capacity of a natural monticellite and phase equilibria in the system CaO-MgO-SiO2-CO2

    Science.gov (United States)

    Sharp, Z.D.; Essene, E.J.; Anovitz, Lawrence M.; Metz, G.W.; Westrum, E.F.; Hemingway, B.S.; Valley, J.W.

    1986-01-01

    The heat capacity of a natural monticellite (Ca1.00Mg.09Fe.91Mn.01Si0.99O3.99) measured between 9.6 and 343 K using intermittent-heating, adiabatic calorimetry yields Cp0(298) and S2980 of 123.64 ?? 0.18 and 109.44 ?? 0.16 J ?? mol-1 K-1 respectively. Extrapolation of this entropy value to end-member monticellite results in an S0298 = 108.1 ?? 0.2 J ?? mol-1 K-1. High-temperature heat-capacity data were measured between 340-1000 K with a differential scanning calorimeter. The high-temperature data were combined with the 290-350 K adiabatic values, extrapolated to 1700 K, and integrated to yield the following entropy equation for end-member monticellite (298-1700 K): ST0(J ?? mol-1 K-1) = S2980 + 164.79 In T + 15.337 ?? 10-3 T + 22.791 ?? 105 T-2 - 968.94. Phase equilibria in the CaO-MgO-SiO2 system were calculated from 973 to 1673 K and 0 to 12 kbar with these new data combined with existing data for akermanite (Ak), diopside (Di), forsterite (Fo), merwinite (Me) and wollastonite (Wo). The location of the calculated reactions involving the phases Mo and Fo is affected by their mutual solid solution. A best fit of the thermodynamically generated curves to all experiments is made when the S0298 of Me is 250.2 J ?? mol-1 K-1 less than the measured value of 253.2 J ?? mol-1 K-1. A best fit to the reversals for the solid-solid and decarbonation reactions in the CaO-MgO-SiO2-CO2 system was obtained with the ??G0298 (kJ ?? mole-1) for the phases Ak(-3667), Di(-3025), Fo(-2051), Me(-4317) and Mo(-2133). The two invariant points - Wo and -Fo for the solid-solid reactions are located at 1008 ?? 5 K and 6.3 ?? 0.1 kbar, and 1361 ?? 10 K and 10.2 ?? 0.2 kbar respectively. The location of the thermodynamically generated curves is in excellent agreement with most experimental data on decarbonation equilibria involving these phases. ?? 1986.

  7. Sound speed of isobaric heat capacity in the saturated and superheated vapour of cesium, rubidium and potassium

    International Nuclear Information System (INIS)

    Novikov, I.I.; Roschupkin, V.V.

    1985-01-01

    The paper reviews the work carried out on the thermodynamic properties of alkali metal vapours. The most systematic investigations concern the sound velocity measurements for saturated and superheated vapours of caesium, for saturated vapour of rubidium, and for superheated vapour of potassium. The Joule-Thompson coefficient has been studied in caesium vapour, and the isobaric heat capacity of potassium vapour has also been examined. The experimental methods for all these experiments are described, and the data obtained are presented in tabular form. (U.K.)

  8. Control of Single-room Ventilation with Regenerative Heat Recovery for Indoor Climate and Energy Performance

    DEFF Research Database (Denmark)

    Smith, Kevin Michael; Svendsen, Svend

    2016-01-01

    constructions and will soon require 85%. The development of single-room ventilation units may aim for these requirements as a result. The exhaust temperatures in highly efficient heat exchangers may approach outdoor levels. The cold exhaust cannot contain ample moisture, so vapour will condense on the heat...... exchanger. Available literature suggests that uncoated rotary heat exchangers transfer this condensate to the supply air, so the drying capacity of the ventilation system may be severely limited. This could raise indoor relative humidities to unsafe levels, which could promote the growth of dust......-mites and mould. Controls may increase drying capacity by increasing ventilation airflow, but this may not be sufficient to limit moisture-related risks. This research investigated the added demand-control measure of reducing variable heat recovery to increase drying capacity when using an uncoated rotary heat...

  9. High-heat tank safety issue resolution program plan

    International Nuclear Information System (INIS)

    Wang, O.S.

    1993-12-01

    The purpose of this program plan is to provide a guide for selecting corrective actions that will mitigate and/or remediate the high-heat waste tank safety issue for single-shell tank (SST) 241-C-106. This program plan also outlines the logic for selecting approaches and tasks to mitigate and resolve the high-heat safety issue. The identified safety issue for high-heat tank 241-C-106 involves the potential release of nuclear waste to the environment as the result of heat-induced structural damage to the tank's concrete, if forced cooling is interrupted for extended periods. Currently, forced ventilation with added water to promote thermal conductivity and evaporation cooling is used to cool the waste. At this time, the only viable solution identified to resolve this safety issue is the removal of heat generating waste in the tank. This solution is being aggressively pursued as the permanent solution to this safety issue and also to support the present waste retrieval plan. Tank 241-C-106 has been selected as the first SST for retrieval. The program plan has three parts. The first part establishes program objectives and defines safety issues, drivers, and resolution criteria and strategy. The second part evaluates the high-heat safety issue and its mitigation and remediation methods and alternatives according to resolution logic. The third part identifies major tasks and alternatives for mitigation and resolution of the safety issue. Selected tasks and best-estimate schedules are also summarized in the program plan

  10. Basic thermo-fluid dynamic problems in high temperature heat exchangers

    International Nuclear Information System (INIS)

    McEligot, D.M.

    1986-01-01

    The authors consider high temperature heat exchangers to be ones where the heat transfer coefficients cannot be predicted confidently by classical analyses for pure forced convection with constant fluid properties. Alternatively, one could consider heat exchangers operating above some arbitrary temperature, say 1000F or 600C perhaps, to be at high temperature conditions. In that case, most common working fluids will be superheated vapors or gases. While some liquid metal heat exchangers are designed to operate in this range, the heat transfer coefficients of liquid metals are usually sufficiently high that the dominant thermal resistance would be due to the second fluid. This paper concentrates on convective heat transfer with gases. Typical applications include modular gas cooled nuclear reactors, proposed nuclear propulsion systems and space power plants, and superheaters in Rankine steam cycles

  11. On the nature of the excess heat capacity of mixing

    Science.gov (United States)

    Benisek, Artur; Dachs, Edgar

    2011-03-01

    The excess vibrational entropy (Δ S {vib/ex}) of several silicate solid solutions are found to be linearly correlated with the differences in end-member volumes (Δ V i ) and end-member bulk moduli (Δκ i ). If a substitution produces both, larger and elastically stiffer polyhedra, then the substituted ion will find itself in a strong enlarged structure. The frequency of its vibration is decreased because of the increase in bond lengths. Lowering of frequencies produces larger heat capacities, which give rise to positive excess vibrational entropies. If a substitution produces larger but elastically softer polyhedra, then increase and decrease of mean bond lengths may be similar in magnitude and their effect on the vibrational entropy tends to be compensated. The empirical relationship between Δ S {vib/ex}, Δ V i and Δκ i , as described by Δ S {vib/ex} = (Δ V i + mΔκ i ) f, was calibrated on six silicate solid solutions (analbite-sanidine, pyrope-grossular, forsterite-fayalite, analbite-anorthite, anorthite-sanidine, CaTs-diopside) yielding m = 0.0246 and f = 2.926. It allows the prediction of Δ S {vib/ex} behaviour of a solid solution based on its volume and bulk moduli end-member data.

  12. BASIMO - Borehole Heat Exchanger Array Simulation and Optimization Tool

    Science.gov (United States)

    Schulte, Daniel O.; Bastian, Welsch; Wolfram, Rühaak; Kristian, Bär; Ingo, Sass

    2017-04-01

    Arrays of borehole heat exchangers are an increasingly popular source for renewable energy. Furthermore, they can serve as borehole thermal energy storage (BTES) systems for seasonally fluctuating heat sources like solar thermal energy or district heating grids. The high temperature level of these heat sources prohibits the use of the shallow subsurface for environmental reasons. Therefore, deeper reservoirs have to be accessed instead. The increased depth of the systems results in high investment costs and has hindered the implementation of this technology until now. Therefore, research of medium deep BTES systems relies on numerical simulation models. Current simulation tools cannot - or only to some extent - describe key features like partly insulated boreholes unless they run fully discretized models of the borehole heat exchangers. However, fully discretized models often come at a high computational cost, especially for large arrays of borehole heat exchangers. We give an update on the development of BASIMO: a tool, which uses one dimensional thermal resistance and capacity models for the borehole heat exchangers coupled with a numerical finite element model for the subsurface heat transport in a dual-continuum approach. An unstructured tetrahedral mesh bypasses the limitations of structured grids for borehole path geometries, while the thermal resistance and capacity model is improved to account for borehole heat exchanger properties changing with depth. Thereby, partly insulated boreholes can be considered in the model. Furthermore, BASIMO can be used to improve the design of BTES systems: the tool allows for automated parameter variations and is readily coupled to other code like mathematical optimization algorithms. Optimization can be used to determine the required minimum system size or to increase the system performance.

  13. Interlaboratory study of the heat capacity of LiNi{sub 1/3}Mn{sub 1/3}Co{sub 1/3}O{sub 2} (NMC111) with layered structure

    Energy Technology Data Exchange (ETDEWEB)

    Cupid, Damian M.; Gotcu, Petronela [Karlsruhe Institute of Technology (KIT), Eggenstein-Leopoldshafen (Germany). Inst. for Applied Materials - Applied Materials Physics (IAM-AWP); Beutl, Alexander [Vienna Univ. (Austria). Inst. of Inorganic Chemistry - Functional Materials; and others

    2017-11-15

    An interlaboratory study was performed to determine the heat capacity of an active material for lithium-ion batteries with layered structure and nominal composition LiNi{sub 1/3} . Mn{sub 1/3}Co{sub 1/3}O{sub 2} (NMC111). The commercial sample, which was characterized using powder X-ray diffraction and inductively coupled plasma-optical emission spectroscopy, is single phase (α-NaFeO{sub 2} crystal structure) with a composition of Li{sub 1.02}Ni{sub 0.32}Mn{sub 0.31}Co{sub 0.30}O{sub 2}. Heat capacity measurements of the homogeneous sample were performed at five laboratories using different operators, methods, devices, temperature ranges, gas atmospheres and crucible materials. The experimental procedures from each laboratory are presented and the results of the individual laboratories are analyzed. Based on a comprehensive evaluation of the data from each laboratory, the heat capacity of the NMC111 sample from 315 K to 1 020 K is obtained with an expanded reproducibility uncertainty of less than 1.22 %.

  14. Experimental studies on a ground coupled heat pump with solar thermal collectors for space heating

    International Nuclear Information System (INIS)

    Xi, Chen; Hongxing, Yang; Lin, Lu; Jinggang, Wang; Wei, Liu

    2011-01-01

    This paper presents experimental studies on a solar-assisted ground coupled heat pump (SAGCHP) system for space heating. The system was installed at the Hebei Academy of Sciences in Shijiazhuang (lat. N38 o 03', long. E114 o 26'), China. Solar collectors are in series connection with the borehole array through plate heat exchangers. Four operation modes of the system were investigated throughout the coldest period in winter (Dec 5th to Dec 27th). The heat pump performance, borehole temperature distributions and solar colleting characteristics of the SAGCHP system are analyzed and compared when the system worked in continuous or intermittent modes with or without solar-assisted heating. The SAGCHP system is proved to perform space heating with high energy efficiency and satisfactory solar fraction, which is a promising substitute for the conventional heating systems. It is also recommended to use the collected solar thermal energy as an alternative source for the heat pump instead of recharging boreholes for heat storage because of the enormous heat capacity of the earth. -- Highlights: → We study four working modes of a solar-assisted ground coupled heat pump. → The heating performance is in direct relation with the borehole temperature. → Solar-assisted heating elevates borehole temperature and system performance. → The system shows higher efficiency over traditional heating systems in cold areas. → Solar heat is not suggested for high temperature seasonal storage.

  15. Residential CO{sub 2} heat pump system for combined space heating and hot water heating

    Energy Technology Data Exchange (ETDEWEB)

    Stene, Joern

    2004-02-01

    Carbon dioxide (CO{sub 2}, R-744) has been identified as a promising alternative to conventional working fluids in a number of applications due to its favourable environmental and thermophysical properties. Previous work on residential CO{sub 2} heat pumps has been dealing with systems for either space heating or hot water heating, and it was therefore considered interesting to carry out a theoretical and experimental study of residential CO{sub 2} heat pump systems for combined space heating and hot water heating - o-called integrated CO{sub 2} heat pump systems. The scope of this thesis is limited to brine-to-water and water-to-water heat pumps connected to low-temperature hydronic space heating systems. The main conclusions are: (1) Under certain conditions residential CO{sub 2} heat pump systems for combined space heating and hot water heating may achieve the same or higher seasonal performance factor (SPF) than the most energy efficient state-of-the-art brine-to-water heat pumps. (2) In contrary to conventional heat pump systems for combined space heating and DHW heating, the integrated CO{sub 2} heat pump system achieves the highest COP in the combined heating mode and the DHW heating mode, and the lowest COP in the space heating mode. Hence, the larger the annual DHW heating demand, the higher the SPF of the integrated CO{sub 2} heat pump system. (3) The lower the return temperature in the space heating system and the lower the DHW storage temperature, the higher the COP of the integrated CO{sub 2} heat pump. A low return temperature in the space heating system also results in a moderate DHW heating capacity ratio, which means that a relatively large part of the annual space heating demand can be covered by operation in the combined heating mode, where the COP is considerably higher than in the space heating mode. (4) During operation in the combined heating mode and the DHW heating mode, the COP of the integrated CO{sub 2} heat pump is heavily influenced by

  16. Transparent hydrogel with enhanced water retention capacity by introducing highly hydratable salt

    Energy Technology Data Exchange (ETDEWEB)

    Bai, Yuanyuan; Xiang, Feng; Wang, Hong, E-mail: hwang@mail.xjtu.edu.cn, E-mail: suo@seas.harvard.edu [Electronic Materials Research Laboratory, School of Electronics and Information Engineering, Xi' an Jiaotong University, Xi' an 710049 (China); Chen, Baohong; Zhou, Jinxiong [State Key Laboratory for Strength and Vibration of Mechanical Structures, International Center for Applied Mechanics and School of Aerospace, Xi' an Jiaotong University, Xi' an 710049 (China); Suo, Zhigang, E-mail: hwang@mail.xjtu.edu.cn, E-mail: suo@seas.harvard.edu [School of Engineering and Applied Sciences, Kavli Institute of Bionano Science and Technology, Harvard University, Cambridge, Massachusetts 02138 (United States)

    2014-10-13

    Polyacrylamide hydrogels containing salt as electrolyte have been used as highly stretchable transparent electrodes in flexible electronics, but those hydrogels are easy to dry out due to water evaporation. Targeted, we try to enhance water retention capacity of polyacrylamide hydrogel by introducing highly hydratable salts into the hydrogel. These hydrogels show enhanced water retention capacity in different level. Specially, polyacrylamide hydrogel containing high content of lithium chloride can retain over 70% of its initial water even in environment with relative humidity of only 10% RH. The excellent water retention capacities of these hydrogels will make more applications of hydrogels become possible.

  17. Transparent hydrogel with enhanced water retention capacity by introducing highly hydratable salt

    International Nuclear Information System (INIS)

    Bai, Yuanyuan; Xiang, Feng; Wang, Hong; Chen, Baohong; Zhou, Jinxiong; Suo, Zhigang

    2014-01-01

    Polyacrylamide hydrogels containing salt as electrolyte have been used as highly stretchable transparent electrodes in flexible electronics, but those hydrogels are easy to dry out due to water evaporation. Targeted, we try to enhance water retention capacity of polyacrylamide hydrogel by introducing highly hydratable salts into the hydrogel. These hydrogels show enhanced water retention capacity in different level. Specially, polyacrylamide hydrogel containing high content of lithium chloride can retain over 70% of its initial water even in environment with relative humidity of only 10% RH. The excellent water retention capacities of these hydrogels will make more applications of hydrogels become possible.

  18. Heat transfer augmentation for high heat flux removal in rib-roughened narrow channels

    International Nuclear Information System (INIS)

    Islam, M.S.; Hino, Ryutaro; Haga, Katsuhiro; Sudo, Yukio; Monde, Masanori.

    1997-03-01

    Heat transfer augmentation in narrow rectangular channels in a target system is a very important method to remove high heat flux up to 12 MW/m 2 generated at target plates of a high-intensity proton accelerator of 1.5 GeV and 1 mA with a proton beam power of 1.5 MW. In this report, heat transfer coefficients and friction factors in narrow rectangular channels with one-sided rib-roughened surface were evaluated for fully developed flows in the range of the Reynolds number from 6,000 to 1,00,000; the rib pitch-to-height ratios (p/k) were 10,20 and 30; the rib height-to-equivalent diameter ratios (k/De) were 0.025, 0.03 and 0.1 by means of previous existing experimental correlations. The rib-roughened surface augmented heat transfer coefficients approximately 4 times higher than the smooth surface at Re=10,000, p/k=10 and k/De=0.1; friction factors increase around 22 times higher. In this case, higher heat flux up to 12 MW/m 2 could be removed from the rib-roughened surface without flow boiling which induces flow instability; but pressure drop reaches about 1.8 MPa. Correlations obtained by air-flow experiments have showed lower heat transfer performance with the water-flow conditions. The experimental apparatus was proposed for further investigation on heat transfer augmentation in very narrow channels under water-flow conditions. This report presents the evaluation results and an outline of the test apparatus. (author)

  19. Use of waste heat from a dairy for heating of a community house

    Energy Technology Data Exchange (ETDEWEB)

    Rehn, C

    1976-01-01

    In a dairy, a lot of cooling capacity is needed. This article describes how this waste heat can be used for heating a community house including a sport establishment and producing hot water for that house. Four different technical solutions are discussed; (1) floor heat, (2) heat transfer connected to the ventilation, (3) regenerative heat exchanger, and (4) use of heat pumps.

  20. Lattice dynamical investigation of the Raman and infrared wave numbers and heat capacity properties of the pyrochlores R2Zr2O7 (R = La, Nd, Sm, Eu)

    Science.gov (United States)

    Nandi, S.; Jana, Y. M.; Gupta, H. C.

    2018-04-01

    A short-range electrostatic forcefield model has been applied for the first time to investigate the Raman and infrared wave numbers in pyrochlore zirconates R2Zr2O7 (R3+ = La, Nd, Sm, Eu). The calculations of phonons involve five stretching and four bending force constants in the Wilson GF matrix method. The calculated phonon wave numbers are in reasonable agreement with the observed spectra in infrared and Raman excitation zones for all of these isomorphous compounds. The contributions of force constants to each mode show a similar trend of variation for all of these compounds. Furthermore, to validate the established forcefield model, we calculated the standard thermodynamic functions, e.g., molar heat capacity, entropy and enthalpy, and compared the results with the previous experimental data for each compound. Using the derived wave numbers for the acoustic and optical modes, the total phonon contribution to the heat capacity was calculated for all these zirconate compounds. The Schottky heat capacity contributions were also calculated for the magnetic compounds, Nd2Zr2O7, Sm2Zr2O7 and Eu2Zr2O7, taking account of crystal-field level schemes of the lanthanide ions. The derived total heat capacity and the integrated values of molar entropy and molar enthalpy showed satisfactory correlations at low temperatures with the experimental results available in the literature for these compounds. At higher temperatures, the discrepancies may be caused by the anharmonic effects of vibrations, phonon dispersion, distribution of phonon density of states, etc.

  1. Reducing Heating In High-Speed Cinematography

    Science.gov (United States)

    Slater, Howard A.

    1989-01-01

    Infrared-absorbing and infrared-reflecting glass filters simple and effective means for reducing rise in temperature during high-speed motion-picture photography. "Hot-mirror" and "cold-mirror" configurations, employed in projection of images, helps prevent excessive heating of scenes by powerful lamps used in high-speed photography.

  2. Design of a natural draft air-cooled condenser and its heat transfer characteristics in the passive residual heat removal system for 10 MW molten salt reactor experiment

    International Nuclear Information System (INIS)

    Zhao, Hangbin; Yan, Changqi; Sun, Licheng; Zhao, Kaibin; Fa, Dan

    2015-01-01

    As one of the Generation IV reactors, Molten Salt Reactor (MSR) has its superiorities in satisfying the requirements on safety. In order to improve its inherent safety, a concept of passive residual heat removal system (PRHRS) for the 10 MW Molten Salt Reactor Experiment (MSRE) was put forward, which mainly consisted of a fuel drain tank, a feed water tank and a natural draft air-cooled condenser (NDACC). Besides, several valves and pipes are also included in the PRHRS. A NDACC for the PRHRS was preliminarily designed in this paper, which contained a finned tube bundle and a chimney. The tube bundle was installed at the bottom of the chimney for increasing the velocity of the air across the bundle. The heat transfer characteristics of the NDACC were investigated by developing a model of the PRHRS using C++ code. The effects of the environmental temperature, finned tube number and chimney height on heat removal capacity of the NDACC were analyzed. The results show that it has sufficient heat removal capacity to meet the requirements of the residual heat removal for MSRE. The effects of these three factors are obvious. With the decay heat reducing, the heat dissipation power declines after a short-time rise in the beginning. The operation of the NDACC is completely automatic without the need of any external power, resulting in a high safety and reliability of the reactor, especially once the accident of power lost occurs to the power plant. - Highlights: • A model to study the heat transfer characteristics of the NDACC was developed. • The NDACC had sufficient heat removal capacity to remove the decay heat of MSRE. • NDACC heat dissipation power depends on outside temperature and condenser geometry. • As time grown, the effects of outside temperature and condenser geometry diminish. • The NDACC could automatically adjust its heat removal capacity

  3. An equivalent marginal cost-pricing model for the district heating market

    International Nuclear Information System (INIS)

    Zhang, Junli; Ge, Bin; Xu, Hongsheng

    2013-01-01

    District heating pricing is a core element in reforming the heating market. Existing district heating pricing methods, such as the cost-plus pricing method and the conventional marginal-cost pricing method, cannot simultaneously provide both high efficiency and sufficient investment cost return. To solve this problem, the paper presents a new pricing model, namely Equivalent Marginal Cost Pricing (EMCP) model, which is based on the EVE pricing theory and the unique characteristics of heat products and district heating. The EMCP model uses exergy as the measurement of heating product value and places products from different district heating regions into the same competition platform. In the proposed model, the return on investment cost is closely related to the quoted cost, and within the limitations of the Heating Capacity Cost Reference and the maximum compensated shadow capacity cost, both lower and higher price speculations of heat producers are restricted. Simulation results show that the model can guide heat producers to bid according to their production costs and to provide reasonable returns on investment, which contributes to stimulate the role of price leverage and to promote the optimal allocation of heat resources. - Highlights: • Presents a new district heating pricing model. • Provides both high market efficiency and sufficient investment cost return. • Provides a competition mechanism for various products from different DH regions. • Both of lower and higher price speculations are restricted in the new model

  4. Heat exchanger for transfering heat produced in a high temperature reactor to an intermediate circuit gas

    International Nuclear Information System (INIS)

    Barchewitz, E.; Baumgaertner, H.

    1985-01-01

    The invention is concerned with improving the arrangement of a heat exchanger designed to transfer heat from the coolant gas circuit of a high temperature reactor to a gas which is to be used for a process heat plant. In the plant the material stresses are to be kept low at high differential pressures and temperatures. According to the invention the tube bundles designed as boxes are fixed within the heat exchanger closure by means of supply pipes having got loops. For conducting the hot gas the heat exchanger has got a central pipe leading out of the reactor vessel through the pod closure and having got only one point of fixation, lying in this closure. Additional advantageous designs are mentioned. (orig./PW)

  5. Heating Performance Analysis of a Geothermal Heat Pump Working with Different Zeotropic and Azeotropic Mixtures

    Directory of Open Access Journals (Sweden)

    Robert Bedoić

    2018-06-01

    Full Text Available The aim of the paper is to examine the possibility of application of the spreadsheet calculator and Reference Fluid Thermodynamic and Transport Properties database to a thermodynamic process. The heating process of a real soil-to-water heat pump, including heat transfer in the borehole heat exchanger has been analysed. How the changes of condensing temperature, at constant evaporating temperature, influence the following: heating capacity, compressor effective power, heat supplied to evaporator, compression discharge temperature and coefficient of performance, are investigated. Also, the energy characteristics of a heat pump using different refrigerants for the same heating capacity and the same temperature regime are compared. The following refrigerants are considered: two zeotropic mixtures, R407C and R409A, a mixture with some zeotropic characteristics, R410A, and an azeotropic mixture, R507A.

  6. P, ρ, T and heat capacity measurements of (α-pinene + β-pinene) mixtures over the temperature range 283.15 K to 358.15 K and pressures up to 40 MPa: Experiments and modelling

    International Nuclear Information System (INIS)

    Langa, Elisa; Palavra, Antonio M.F.; Lourenço, Maria J.V.; Nieto de Castro, Carlos A.; Mainar, Ana M.

    2013-01-01

    Highlights: ► Density as a function of P, T and composition was measured for pinene mixtures. ► Isothermal compressibility and coefficients of cubic expansion were also calculated. ► Isobaric heat capacity was also determined as function of temperature and composition. ► Usual behaviour of these properties was found. ► SAFT and PC-SAFT were used as predictive models, showing PC-SAFT the best predictions. - Abstract: The density and isobaric heat capacity of the binary system {α-pinene (4,7,7-trimethylbicyclo[3.1.1]hept-3-ene (1), CAS Number 7785-26-4) + β-pinene (6,6-dimethyl-2-methylene-bicyclo[3.1.1]heptane (2), CAS Number 127-91-3)} has been measured for eleven different compositions. The density was determined at five pressures from (20 MPa to 40 MPa) and temperatures from (283.15 K to 358.15 K) and the isobaric heat capacity at atmospheric pressure and temperatures from (313.15 K to 418.15 K). Density was measured with an experimental uncertainty estimated to be ± 0.5 kg·m −3 . The isothermal compressibility and isobaric thermal expansion were derived from the experimental density data. The isobaric heat capacity was determined with a DSC calorimeter being the experimental uncertainty lower than 1.5%. Isobaric heat capacity behaviour was as expected for both pure compounds and for mixtures. Two different equations of state, conventional SAFT and PC-SAFT, were applied to calculate the densities of the mixture, being the best predictions achieved with PC-SAFT equation.

  7. Low temperature measurements of the heat capacity and thermodynamic functions of pseudo-malachite Cu5(PO4)2(OH)4

    International Nuclear Information System (INIS)

    Bissengaliyeva, M.R.; Gogol, D.B.; Bekturganov, N.S.

    2012-01-01

    The investigation of the heat capacity of a natural specimen of copper phosphate—pseudo-malachite Cu 5 (PO 4 ) 2 (OH) 4 in the temperature range between 4.2 K and 320 K has been carried out by the method of low-temperature adiabatic calorimetry. Tabulated values of the heat capacity and thermodynamic functions of the mineral including the changes of entropy and enthalpy and the Gibbs function of free energy have been calculated. The standard values of thermodynamic functions of pseudo-malachite at T = 298.15 K are C p,m ° =(385.43±0.41)J mole −1  K −1 , Δ 0 T S m ° =(412.16±0.61)J mole −1  K −1 , Δ 0 T H m ° =(63681.5±57.0)J mole −1 , F m ° =(198.57±0.47)J mole −1  K −1 . In the low-temperature area 0 tr = (5.772 ± 0.081) J mole −1 K −1 , ΔH tr = (29.94 ± 0.42) J mole −1 .

  8. Nitrogen expander cycles for large capacity liquefaction of natural gas

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Ho-Myung; Park, Jae Hoon; Gwak, Kyung Hyun [Hong Ik University, Department of Mechanical Engineering, Seoul, 121-791 (Korea, Republic of); Choe, Kun Hyung [Korea Gas Corporation, Incheon, 406-130 (Korea, Republic of)

    2014-01-29

    Thermodynamic study is performed on nitrogen expander cycles for large capacity liquefaction of natural gas. In order to substantially increase the capacity, a Brayton refrigeration cycle with nitrogen expander was recently added to the cold end of the reputable propane pre-cooled mixed-refrigerant (C3-MR) process. Similar modifications with a nitrogen expander cycle are extensively investigated on a variety of cycle configurations. The existing and modified cycles are simulated with commercial process software (Aspen HYSYS) based on selected specifications. The results are compared in terms of thermodynamic efficiency, liquefaction capacity, and estimated size of heat exchangers. The combination of C3-MR with partial regeneration and pre-cooling of nitrogen expander cycle is recommended to have a great potential for high efficiency and large capacity.

  9. Nitrogen expander cycles for large capacity liquefaction of natural gas

    Science.gov (United States)

    Chang, Ho-Myung; Park, Jae Hoon; Gwak, Kyung Hyun; Choe, Kun Hyung

    2014-01-01

    Thermodynamic study is performed on nitrogen expander cycles for large capacity liquefaction of natural gas. In order to substantially increase the capacity, a Brayton refrigeration cycle with nitrogen expander was recently added to the cold end of the reputable propane pre-cooled mixed-refrigerant (C3-MR) process. Similar modifications with a nitrogen expander cycle are extensively investigated on a variety of cycle configurations. The existing and modified cycles are simulated with commercial process software (Aspen HYSYS) based on selected specifications. The results are compared in terms of thermodynamic efficiency, liquefaction capacity, and estimated size of heat exchangers. The combination of C3-MR with partial regeneration and pre-cooling of nitrogen expander cycle is recommended to have a great potential for high efficiency and large capacity.

  10. Nitrogen expander cycles for large capacity liquefaction of natural gas

    International Nuclear Information System (INIS)

    Chang, Ho-Myung; Park, Jae Hoon; Gwak, Kyung Hyun; Choe, Kun Hyung

    2014-01-01

    Thermodynamic study is performed on nitrogen expander cycles for large capacity liquefaction of natural gas. In order to substantially increase the capacity, a Brayton refrigeration cycle with nitrogen expander was recently added to the cold end of the reputable propane pre-cooled mixed-refrigerant (C3-MR) process. Similar modifications with a nitrogen expander cycle are extensively investigated on a variety of cycle configurations. The existing and modified cycles are simulated with commercial process software (Aspen HYSYS) based on selected specifications. The results are compared in terms of thermodynamic efficiency, liquefaction capacity, and estimated size of heat exchangers. The combination of C3-MR with partial regeneration and pre-cooling of nitrogen expander cycle is recommended to have a great potential for high efficiency and large capacity

  11. Free-space optical communications with peak and average constraints: High SNR capacity approximation

    KAUST Repository

    Chaaban, Anas; Morvan, Jean-Marie; Alouini, Mohamed-Slim

    2015-01-01

    . Numerical evaluation shows that this capacity lower bound is nearly tight at high signal-to-noise ratio (SNR), while it is shown analytically that the gap to capacity upper bounds is a small constant at high SNR. In particular, the gap to the high

  12. Low-temperature heat capacity and thermodynamic properties of [Re2(Ile)4(H2O)8](ClO4)6 (Re=Nd, Er, Ile=isoleucine)

    International Nuclear Information System (INIS)

    Lan Xiaozheng; Tan Zhicheng; Liu Beiping; Nan Zhaodong; Sun Lixian; Xu Fen

    2003-01-01

    The heat capacities of two kinds of rare-earth element solid complexes with isoleucine [Re 2 (Ile) 4 (H 2 O) 8 ](ClO 4 ) 6 (where Re=Nd, Er, and Ile=isoleucine) have been measured by an automatic adiabatic calorimeter in the temperature range from 80 to 370 K. Two solid-solid phase transitions were found from the C p curve of Nd formed complex in the range of 165-175 K with a peak temperature of 167.88 K and in the range of 195-210 K with a peak temperature of 202.13 K. The corresponding molar enthalpies of these phase transitions were determined to be 404.61 J mol -1 and 2.955 kJ mol -1 , respectively. One solid-solid phase transition was found for the Er formed complex in the range of 190-205 K with a peak temperature of 193.42 K. The corresponding molar enthalpy of this transition was 14.11 kJ mol -1 . Smooth heat capacities and thermodynamic functions relative to the standard state (298.15 K), H T -H 298.15 , S T -S 298.15 and -[G T -G 298.15 ], of the two compounds, were calculated on basis of experimental heat capacity data. Possible mechanisms of thermal decompositions for the pair of compounds were suggested according to the thermogravimetric (TG) analysis

  13. Thermophysical Properties of Cold and Vacuum Plasma Sprayed Cu-Cr-X Alloys, NiAl and NiCrAlY Coatings. Part 2; Specific Heat Capacity

    Science.gov (United States)

    Raj, S. V.

    2017-01-01

    Part I of the paper discussed the temperature dependencies of the electrical resistivities, thermal conductivities, thermal diffusivities and total hemispherical emissivities of several vacuum plasma sprayed (VPS) and cold sprayed copper alloy monolithic coatings, VPS NiAl, VPS NiCrAlY, extruded GRCop-84 and as-cast Cu-17(wt.%)Cr-5%Al. Part II discusses the temperature dependencies of the constant pressure specific heat capacities, CP, of these coatings. The data were empirically were regression-fitted with the equation: CP = AT4 + BT3 + CT2 + DT +E where T is the absolute temperature and A, B, C, D and E are regression constants. The temperature dependencies of the molar enthalpy, molar entropy and Gibbs molar free energy determined from experimental values of molar specific heat capacity are reported. Calculated values of CP using the Neumann-Kopp (NK) rule were in poor agreement with experimental data. Instead, a modification of the Neumann-Kopp rule was found to predict values closer to the experimental data with an absolute deviation less than 6.5%. The specific molar heat capacities for all the alloys did not agree with the Dulong-Petit law, and CP is greater than 3R, where R is the universal gas constant, were measured for all the alloys except NiAl for which CP is less than 3R at all temperatures.

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

    International Nuclear Information System (INIS)

    TeGrotenhuis, W.E.; Humble, P.H.; Sweeney, J.B.

    2012-01-01

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

  15. Active latent heat storage with a screw heat exchanger - experimental results for heat transfer and concept for high pressure steam

    Science.gov (United States)

    Zipf, Verena; Willert, Daniel; Neuhäuser, Anton

    2016-05-01

    An innovative active latent heat storage concept was invented and developed at Fraunhofer ISE. It uses a screw heat exchanger (SHE) for the phase change during the transport of a phase change material (PCM) from a cold to a hot tank or vice versa. This separates heat transfer and storage tank in comparison to existing concepts. A test rig has been built in order to investigate the heat transfer coefficients of the SHE during melting and crystallization of the PCM. The knowledge of these characteristics is crucial in order to assess the performance of the latent heat storage in a thermal system. The test rig contains a double shafted SHE, which is heated or cooled with thermal oil. The overall heat transfer coefficient U and the convective heat transfer coefficient on the PCM side hPCM both for charging and discharging have been calculated based on the measured data. For charging, the overall heat transfer coefficient in the tested SHE was Uch = 308 W/m2K and for discharging Udis = 210 W/m2K. Based on the values for hPCM the overall heat transfer coefficients for a larger SHE with steam as heat transfer fluid and an optimized geometry were calculated with Uch = 320 W/m2K for charging and Udis = 243 W/m2K for discharging. For pressures as high as p = 100 bar, an SHE concept has been developed, which uses an organic fluid inside the flight of the SHE as working media. With this concept, the SHE can also be deployed for very high pressure, e.g. as storage in solar thermal power plants.

  16. Recycling rice husks for high-capacity lithium battery anodes.

    Science.gov (United States)

    Jung, Dae Soo; Ryou, Myung-Hyun; Sung, Yong Joo; Park, Seung Bin; Choi, Jang Wook

    2013-07-23

    The rice husk is the outer covering of a rice kernel and protects the inner ingredients from external attack by insects and bacteria. To perform this function while ventilating air and moisture, rice plants have developed unique nanoporous silica layers in their husks through years of natural evolution. Despite the massive amount of annual production near 10(8) tons worldwide, so far rice husks have been recycled only for low-value agricultural items. In an effort to recycle rice husks for high-value applications, we convert the silica to silicon and use it for high-capacity lithium battery anodes. Taking advantage of the interconnected nanoporous structure naturally existing in rice husks, the converted silicon exhibits excellent electrochemical performance as a lithium battery anode, suggesting that rice husks can be a massive resource for use in high-capacity lithium battery negative electrodes.

  17. Indoor temperatures for calculating room heat loss and heating capacity of radiant heating systems combined with mechanical ventilation systems

    DEFF Research Database (Denmark)

    Wu, Xiaozhou; Olesen, Bjarne W.; Fang, Lei

    2016-01-01

    change rates on the indoor temperatures were performed using the proposed model. When heated surface temperatures and air change rates were from 21.0 to 29.0 degrees C and from 0.5 to 4.0 h-1, the indoor temperatures for calculating the transmission heat loss and ventilation heat loss were between 20...

  18. Transparent hydrogel with enhanced water retention capacity by introducing highly hydratable salt

    OpenAIRE

    Bai, Yuanyuan; Chen, Baohong; Xiang, Feng; Zhou, Jinxiong; Wang, Hong; Suo, Zhigang

    2014-01-01

    Polyacrylamide hydrogels containing salt as electrolyte have been used as highly stretchable transparent electrodes in flexible electronics, but those hydrogels are easy to dry out due to water evaporation. Targeted, we try to enhance water retention capacity of polyacrylamide hydrogel by introducing highly hydratable salts into the hydrogel. These hydrogels show enhanced water retention capacity in different level. Specially, polyacrylamide hydrogel containing high content of lithium chlorid...

  19. Solar Heating System with Building-Integrated Heat Storage

    DEFF Research Database (Denmark)

    Heller, Alfred

    1996-01-01

    Traditional solar heating systems cover between 5 and 10% of the heat demand fordomestic hot water and comfort heating. By applying storage capacity this share can beincreased much. The Danish producer of solar heating systems, Aidt-Miljø, markets such a system including storage of dry sand heated...... by PP-pipe heat exchanger. Heat demand is reduced due to direct solar heating, and due to storage. Heat demand is reduced due to direct solar heating, due to storage and due to lower heat losses through the ground. In theory, by running the system flow backwards through the sand storage, active heating...... can be achieved.The objective of the report is to present results from measured system evaluation andcalculations and to give guidelines for the design of such solar heating systems with building integrated sand storage. The report is aimed to non-technicians. In another report R-006 the main results...

  20. CASTOR registered HAW28M - a high heat load cask for transport and storage of vitrified high level waste containers

    International Nuclear Information System (INIS)

    Vossnacke, A.; Klein, K.; Kuehne, B.

    2004-01-01

    Within the German return programme for vitrified high level waste (HLW) from reprocessing at COGEMA and BNFL up to now 39 casks loaded with 28 containers each were transported back to Germany and are stored in the Interim Storage Facility Gorleben (TBL-G) for up to 40 years. For transport and storage in all but one case the GNB casks CASTOR registered HAW 20/28 CG have been used. This cask type is designed to accommodate 20 or 28 HLW containers with a total thermal power of 45 kW maximum. In the near future, among the high level waste, which has to be returned to Germany, there will be an increasing number of containers of which the heat capacity and radioactive inventory will exceed the technical limits of the CASTOR registered HAW 20/28 CG. Therefore GNB has started the development of a new cask generation, named CASTOR registered HAW28M, meeting these future requirements. The CASTOR registered HAW28M is especially developed for the transport of vitrified residues from France and Great Britain to Germany. It complies with the international regulations for type B packages according to IAEA (International Atomic Energy Agency). It is thus guaranteed that even in case of any accident the cask body and the lid system remain functional and the safe confinement of the radioactive contents remains intact during transport. The CASTOR registered HAW28M fulfills not only the requirements for transport but also the acceptance criteria of interim storage: radiation shielding, heat dissipation, safe confinement under both normal and hypothetical accident conditions. Storage buildings such as the TBL-G simply support the safety functions of the cask. The challenge for the development results from higher requirements of the technical specification, particularly related to fuel which is reprocessed. As a consequence of the reprocessing of fuel with increased enrichment and burn up, higher heat capacity and sophisticated shielding measures have to be considered. For the CASTOR

  1. High-capacity composite adsorbents for nucleic acids.

    Science.gov (United States)

    Tiainen, Peter; Rokebul Anower, M; Larsson, Per-Olof

    2011-08-05

    Cytopore™ is a bead-shaped, macroporous and easily compressible cellulose-based anion-exchange material intended for cultivation of anchor-dependent animal cells. Reticulated vitreous carbon (RVC) is a strong, non-compressible, high voidage (97%) matrix material that can be cut to desired geometrical shapes. Cytopore and RVC were combined to cylindrical composites (25 mm × 10 mm) fitted inside chromatography columns. The composite combined the advantageous properties of both its constituents, making it suitable for column chromatography. The composite could withstand very high flow rates without compaction of the bed (>25 column volumes/min; 4000 cm h(-1)). Chromatography runs with tracers showed a low HETP value (0.3mm), suggesting that pore flow was in operation. The dynamic binding capacities (10% breakthrough) per gram of dry weight Cytopore were determined for several compounds including DNA and RNA and were found to be 240-370 mg/g. The composite was used to isolate pUC 18-type plasmids from a cleared alkaline lysate in a good yield. Confocal microscopy studies showed that plasmids were bound not only to the surface of the Cytopore material but also within the matrix walls, thus offering an explanation to the very high binding capacities observed. The concept of using a composite prepared from a mechanically weak, high-binding material and a strong scaffold material may be applied to other systems as well. Copyright © 2011 Elsevier B.V. All rights reserved.

  2. Prospects for development of heat supply systems in high-rise districts

    Science.gov (United States)

    Zhila, Viktor; Solovyeva, Elena

    2018-03-01

    The article analyzes the main advantages and disadvantages of centralized and decentralized heat supply systems in high-rise districts. The main schemes of centralized heat supply systems are considered. They include centralized heat supply from boiler houses, centralized heat supply from autonomous heat sources, heat supply from roof boiler houses and door-to-door heating supply. For each of these variant, the gas distribution systems are considered and analyzed. These systems vary depending on the heat source location. For each of these systems, technical and economic indicators are taken into account, the analysis of which allows choosing the best option for districts where high-rise buildings predominate.

  3. Secondary heat exchanger design and comparison for advanced high temperature reactor

    International Nuclear Information System (INIS)

    Sabharwall, P.; Kim, E. S.; Siahpush, A.; McKellar, M.; Patterson, M.

    2012-01-01

    Next generation nuclear reactors such as the advanced high temperature reactor (AHTR) are designed to increase energy efficiency in the production of electricity and provide high temperature heat for industrial processes. The efficient transfer of energy for industrial applications depends on the ability to incorporate effective heat exchangers between the nuclear heat transport system and the industrial process heat transport system. This study considers two different types of heat exchangers - helical coiled heat exchanger and printed circuit heat exchanger - as possible options for the AHTR secondary heat exchangers with distributed load analysis and comparison. Comparison is provided for all different cases along with challenges and recommendations. (authors)

  4. Assessment of Potential Capacity Increases at Combined Heat and Power Facilities Based on Available Corn Stover and Forest Logging Residues

    Directory of Open Access Journals (Sweden)

    Donald L. Grebner

    2013-08-01

    Full Text Available Combined Heat and Power (CHP production using renewable energy sources is gaining importance because of its flexibility and high-energy efficiency. Biomass materials, such as corn stover and forestry residues, are potential sources for renewable energy for CHP production. In Mississippi, approximately 4.0 MT dry tons of woody biomass is available annually for energy production. In this study, we collected and analyzed 10 years of corn stover data (2001–2010 and three years of forest logging residue data (1995, 1999, and 2002 in each county in Mississippi to determine the potential of these feed stocks for sustainable CHP energy production. We identified six counties, namely Amite, Copiah, Clarke, Wayne, Wilkinson and Rankin, that have forest logging residue feedstocks to sustain a CHP facility with a range of capacity between 8.0 and 9.8 MW. Using corn stover alone, Yazoo and Washington counties can produce 13.4 MW and 13.5 MW of energy, respectively. Considering both feedstocks and based on a conservative amount of 30% available forest logging residue and 33% corn stover, we found that 20 counties have adequate supply for a CHP facility with a capacity of 8.3 MW to 19.6 MW.

  5. Heat buffers improve capacity and exploitation degree of geothermal energy sources

    NARCIS (Netherlands)

    Ooster, A.van t; Wit, J. de; Janssen, E.G.O.N.; Ruigrok, J.

    2008-01-01

    This research focuses on the role of heat buffers to support optimal use of combinations of traditional and renewable heat sources like geothermal heat for greenhouse heating. The objective was to determine the contribution of heat buffers to effective new combinations of resources that satisfy

  6. Apparent molar volumes and apparent molar heat capacities of Pr(NO{sub 3}){sub 3}(aq), Gd(NO{sub 3}){sub 3}(aq), Ho(NO{sub 3}){sub 3}(aq), and Y(NO{sub 3}){sub 3}(aq) at T (288.15, 298.15, 313.15, and 328.15) K and p = 0.1 MPa

    Energy Technology Data Exchange (ETDEWEB)

    Hakin, Andrew W. [Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, T1K 3M4 (Canada)]. E-mail: hakin@uleth.ca; Liu Jinlian [Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, T1K 3M4 (Canada); Erickson, Kristy [Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, T1K 3M4 (Canada); Munoz, Julie-Vanessa [Department of Chemistry and Biochemistry, University of Lethbridge, 4401 University Drive, Lethbridge, Alberta, T1K 3M4 (Canada); Rard, Joseph A. [Energy and Environment Directorate, Lawrence Livermore National Laboratory, University of California, Livermore, CA 94550 (United States)

    2005-02-01

    Relative densities and relative massic heat capacities have been measured for acidified solutions of Y(NO{sub 3}){sub 3}(aq), Pr(NO{sub 3}){sub 3}(aq), and Gd(NO{sub 3}){sub 3}(aq) at T = (288.15, 298.15, 313.15, and 328.15) K and p = 0.1 MPa. In addition, relative densities and massic heat capacities have been measured at the same temperatures and pressure for Y(NO{sub 3}){sub 3}(aq) and Ho(NO{sub 3}){sub 3}(aq) solutions without excess acid (n.b. measurements at T = 328.15 K for Ho(NO{sub 3}){sub 3}(aq) were not performed due to the limited volume of solution available). Apparent molar volumes and apparent molar heat capacities for the aqueous salt solutions have been calculated from the experimental apparent molar properties of the acidified solutions using Young's rule, whereas the apparent molar properties of the solutions without excess acid were calculated directly from the measured densities and massic heat capacities. The two sets of data for the Y(NO{sub 3}){sub 3}(aq) systems provide a check of the internal consistency of the Young's rule approach we have utilised. The concentration dependences of the apparent molar volumes and heat capacities of the aqueous salt solutions have been modelled at each investigated temperature using the Pitzer ion interaction equations to yield apparent molar properties at infinite dilution. Complex formation within the aqueous rare earth nitrate systems is discussed qualitatively by probing the concentration dependence of apparent molar volumes and heat capacities. In spite of the complex formation in the aqueous rare earth nitrate systems, there is a high degree of self-consistency between the apparent molar volumes and heat capacities at infinite dilution reported in this manuscript and those previously reported for aqueous rare earth perchlorates.

  7. Can high temperature steam electrolysis function with geothermal heat?

    International Nuclear Information System (INIS)

    Sigurvinsson, J.; Mansilla, C.; Werkoff, F.; Lovera, P.

    2007-01-01

    It is possible to improve the performance of electrolysis processes by operating at a high temperature. This leads to a reduction in electricity consumption but requires a part of the energy necessary for the dissociation of water to be in the form of thermal energy. Iceland produces low cost electricity and very low cost geothermal heat. However, the temperature of geothermal heat is considerably lower than the temperature required at the electrolyser's inlet, making heat exchangers necessary to recuperate part of the heat contained in the gases at the electrolyser's outlet. A techno-economic optimisation model devoted to a high-temperature electrolysis (HTE) process which includes electrolysers as well as a high temperature heat exchanger network was created. Concerning the heat exchangers, the unit costs used in the model are based on industrial data. For the electrolyser cells, the unit cost scaling law and the physical sub-model we used were formulated using analogies with solid oxide fuel cells. The method was implemented in a software tool, which performs the optimisation using genetic algorithms. The first application of the method is done by taking into account the prices of electricity and geothermal heat in the Icelandic context. It appears that even with a geothermal temperature as low as 230 degrees C, the HTE could compete with alkaline electrolysis. (authors)

  8. Rapid Preparation of Biosorbents with High Ion Exchange Capacity from Rice Straw and Bagasse for Removal of Heavy Metals

    Directory of Open Access Journals (Sweden)

    Supitcha Rungrodnimitchai

    2014-01-01

    Full Text Available This work describes the preparation of the cellulose phosphate with high ion exchange capacity from rice straw and bagasse for removal of heavy metals. In this study, rice straw and bagasse were modified by the reaction with phosphoric acid in the presence of urea. The introduced phosphoric group is an ion exchangeable site for heavy metal ions. The reaction by microwave heating yielded modified rice straw and modified bagasse with greater ion exchange capacities (∼3.62 meq/g and shorter reaction time (1.5–5.0 min than the phosphorylation by oil bath heating. Adsorption experiments towards Pb2+, Cd2+, and Cr3+ ions of the modified rice straw and the modified bagasse were performed at room temperature (heavy metal concentration 40 ppm, adsorbent 2.0 g/L. The kinetics of adsorption agreed with the pseudo-second-order model. It was shown that the modified rice straw and the modified bagasse could adsorb heavy metal ions faster than the commercial ion exchange resin (Dowax. As a result of Pb2+ sorption test, the modified rice straw (RH-NaOH 450W removed Pb2+ much faster in the initial step and reached 92% removal after 20 min, while Dowax (commercial ion exchange resin took 90 min for the same removal efficiency.

  9. Confinement of ohmically heated plasmas and turbulent heating in high-magnetic field tokamak TRIAM-1

    Energy Technology Data Exchange (ETDEWEB)

    Hiraki, N; Itoh, S; Kawai, Y; Toi, K; Nakamura, K [Kyushu Univ., Fukuoka (Japan). Research Inst. for Applied Mechanics

    1979-12-01

    TRIAM-1, the tokamak device with high toroidal magnetic field, has been constructed to establish the scaling laws of advanced tokamak devices such as Alcator, and to study the possibility of the turbulent heating as a further economical heating method of the fusion oriented plasmas. The plasma parameters obtained by ohmic heating alone are as follows; central electron temperature T sub(e0) = 640 eV, central ion temperature T sub(i0) = 280 eV and line-average electron density n average sub(e) = 2.2 x 10/sup 14/ cm/sup -3/. The empirical scaling laws are investigated concerning T sub(e0), T sub(i0) and n average sub(e). The turbulent heating has been carried out by applying the high electric field in the toroidal direction to the typical tokamak discharge with T sub(i0) asymptotically equals 200 eV. The efficient ion heating is observed and T sub(i0) attains to about 600 eV.

  10. Energy efficient ammonia heat pump. Final report

    Energy Technology Data Exchange (ETDEWEB)

    Madsen, Claus; Pijnenburg, B.; Schumann Grindorf, H. [Danish Technological Institute, Aarhus (Denmark); Christensen, Rolf [Alfa Laval, Lund (Sweden); Rasmussen, Bjarne D. [Grundfos, Bjerringbro (Denmark); Gram, S.; Fredborg Jakobsen, D. [Svedan Industri Koeleanlaeg, Greve (Denmark)

    2013-09-15

    The report describes the development of a highly effective ammonia heat pump. Heat pumps play an increasingly important role in the search for more effective use of energy in our society. Highly efficient heat pumps can contribute to reduced energy consumption and improved economy of the systems which they are a part of. An ammonia heat pump with high pressure reciprocating compressor and a novel split condenser was developed to prove potential for efficiency optimization. The split of the condenser in two parts can be utilized to obtain smaller temperature approaches and, thereby, improved heat pump efficiency at an equal heat exchanger area, when compared to the traditional solution with separate condenser and de-superheater. The split condenser design can also be exploited for heating a significant share of the total heating capacity to a temperature far above the condensing temperature. Furthermore, the prototype heat pump was equipped with a plate type evaporator combined with a U-turn separator with a minimum liquid height and a liquid pump with the purpose of creating optimum liquid circulation ratio for the highest possible heat transfer coefficients at the lowest possible pressure drop. The test results successfully confirmed the highest possible efficiency; a COP of 4.3 was obtained when heating water from 40 deg. C to 80 deg. C while operating with evaporating/condensing temperatures of +20 deg C/+73 deg C. (Author)

  11. Progress of High Heat Flux Component Manufacture and Heat Load Experiments in China

    Energy Technology Data Exchange (ETDEWEB)

    Liu, X.; Lian, Y.; Xu, Z.; Chen, J.; Chen, L.; Wang, Q.; Duan, X., E-mail: xliu@swip.ac.cn [Southwestern Institute of Physics, Chengu (China); Luo, G. [Institute of Plasma Physics, Chinese Academy of Sciences, Hefei (China); Yan, Q. [University of Science and Technology Beijing, Beijing (China)

    2012-09-15

    Full text: High heat flux components for first wall and divertor are the key subassembly of the present fusion experiment apparatus and fusion reactors in the future. It is requested the metallurgical bonding among the plasma facing materials (PFMs), heat sink and support materials. As to PFMs, ITER grade vacuum hot pressed beryllium CN-G01 was developed in China and has been accepted as the reference material of ITER first wall. Additionally pure tungsten and tungsten alloys, as well as chemical vapor deposition (CVD) W coating are being developed for the aims of ITER divertor application and the demand of domestic fusion devices, and significant progress has been achieved. For plasma facing components (PFCs), high heat flux components used for divertor chamber are being studied according to the development program of the fusion experiment reactor of China. Two reference joining techniques of W/Cu mockups for ITER divertor chamber are being developed, one is mono-block structure by pure copper casting of tungsten surface following by hot iso-static press (HIP), and another is flat structure by brazing. The critical acceptance criteria of high heat flux components are their high heat load performance. A 60 kW Electron-beam Material testing Scenario (EMS-60) has been constructed at Southwestern Institute of Physics (SWIP),which adopts an electron beam welding gun with maximum energy of 150 keV and 150 x 150 mm{sup 2} scanning area by maximum frame rate of 30 kHz. Furthermore, an Engineering Mockup testing Scenario (EMS-400) facility with 400 kW electron-beam melting gun is under construction and will be available by the end of this year. After that, China will have the comprehensive capability of high heat load evaluation from PFMs and small-scale mockups to engineering full scale PFCs. A brazed W/CuCrZr mockup with 25 x 25 x 40 mm{sup 3} in dimension was tested at EMS-60. The heating and cooling time are 10 seconds and 15 seconds, respectively. The experiment

  12. A Numerical Study on the Heat Transfer Characteristics of a Solar Thermal Receiver with High-temperature Heat Pipes

    International Nuclear Information System (INIS)

    Park, Young Hark; Jung, Eui Guk; Boo, Joon Hong

    2007-01-01

    A numerical analysis was conducted to predict the heat transfer characteristics of a solar receiver which is subject to very high heat fluxes and temperatures for solar thermal applications. The concentration ratio of the solar receiver ranges from 200 to 1000 and the concentrated heat is required to be transported to a certain distance for specific applications. The study deals with a solar receiver incorporating high-temperature sodium heat pipe as well as typical one that employs a molten-salt circulation loop. The isothermal characteristics in the receiver section is of major concern. The diameter of the solar thermal receiver was 120 mm and the length was 400 mm. For the molten-salt circulation type receiver, 48 axial channels of the same dimensions were attached to the outer wall of the receiver with even spacing in the circumferential direction. The molten salt fed through the channels by forced convection using a special pump. For the heat pipe receiver, the channels are changed to high-temperature sodium heat pipes. Commercial softwares were employed to deal with the radiative heat transfer inside the receiver cavity and the convection heat transfer along the channels. The numerical results are compared and analyzed from the view point of high-temperature solar receiver

  13. Cold Heat Release Characteristics of Solidified Oil Droplet-Water Solution Latent Heat Emulsion by Air Bubbles

    Science.gov (United States)

    Inaba, Hideo; Morita, Shin-Ichi

    The present work investigates the cold heat-release characteristics of the solidified oil droplets (tetradecane, C14H30, freezing point 278.9 K)/water solution emulsion as a latent heat-storage material having a low melting point. An air bubbles-emulsion direct-contact heat exchange method is selected for the cold heat-results from the solidified oil droplet-emulsion layer. This type of direct-contact method results in the high thermal efficiency. The diameter of air bubbles in the emulsion increases as compared with that in the pure water. The air bubbles blown from a nozzle show a strong mixing behavior during rising in the emulsion. The temperature effectiveness, the sensible heat release time and the latent heat release time have been measured as experimental parameters. The useful nondimensional emulsion level equations for these parameters have been derived in terms of the nondimensional emalsion level expressed the emulsion layer dimensions, Reynolds number for air flow, Stefan number and heat capacity ratio.

  14. Heat capacities, third-law entropies and thermodynamic functions of the negative thermal expansion materials, cubic α-ZrW2O8 and cubic ZrMo2O8, from T=(0 to 400) K

    International Nuclear Information System (INIS)

    Stevens, Rebecca; Linford, Jessica; Woodfield, Brian F.; Boerio-Goates, Juliana.; Lind, Cora; Wilkinson, Angus P.; Kowach, Glen

    2003-01-01

    The molar heat capacities of crystalline cubic α-ZrW 2 O 8 and cubic ZrMo 2 O 8 have been measured at temperatures from (0.6 to 400) K. At T=298.15 K, the standard molar heat capacities are (207.01±0.21) J·K -1 ·mol -1 for the tungstate and (210.06±0.42) J·K -1 ·mol -1 for the molybdate. Thermodynamic functions have been generated from smoothed fits of the experimental results. The standard molar entropies for the tungstate and molybdate are (257.96±0.50) J·K -1 ·mol -1 and (254.3±1) J·K -1 ·mol -1 , respectively. The uncertainty of the entropy of the cubic ZrMo 2 O 8 is larger due to the presence of small chemical and phase impurities whose effects cannot be corrected for at this time. The heat capacities of the negative thermal expansion materials have been compared to the weighted sums of their constituent binary oxides. Both negative thermal expansion materials have heat capacities which are significantly greater than the sum of the binary oxides over the entire temperature region

  15. Process heat cogeneration using a high temperature reactor

    International Nuclear Information System (INIS)

    Alonso, Gustavo; Ramirez, Ramon; Valle, Edmundo del; Castillo, Rogelio

    2014-01-01

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

  16. Process heat cogeneration using a high temperature reactor

    Energy Technology Data Exchange (ETDEWEB)

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

    2014-12-15

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

  17. 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

  18. Comfortable, high-efficiency heat pump with desiccant-coated, water-sorbing heat exchangers.

    Science.gov (United States)

    Tu, Y D; Wang, R Z; Ge, T S; Zheng, X

    2017-01-12

    Comfortable, efficient, and affordable heating, ventilation, and air conditioning systems in buildings are highly desirable due to the demands of energy efficiency and environmental friendliness. Traditional vapor-compression air conditioners exhibit a lower coefficient of performance (COP) (typically 2.8-3.8) owing to the cooling-based dehumidification methods that handle both sensible and latent loads together. Temperature- and humidity-independent control or desiccant systems have been proposed to overcome these challenges; however, the COP of current desiccant systems is quite small and additional heat sources are usually needed. Here, we report on a desiccant-enhanced, direct expansion heat pump based on a water-sorbing heat exchanger with a desiccant coating that exhibits an ultrahigh COP value of more than 7 without sacrificing any comfort or compactness. The pump's efficiency is doubled compared to that of pumps currently used in conventional room air conditioners, which is a revolutionary HVAC breakthrough. Our proposed water-sorbing heat exchanger can independently handle sensible and latent loads at the same time. The desiccants adsorb moisture almost isothermally and can be regenerated by condensation heat. This new approach opens up the possibility of achieving ultrahigh efficiency for a broad range of temperature- and humidity-control applications.

  19. Leaching and heating process as alternative to produce fish protein powder from Kilka (Clupeonella cultiventris caspia

    Directory of Open Access Journals (Sweden)

    KAVEH RAHMANIFARAH

    2014-05-01

    Full Text Available Rahmanifarah K, Shabanpour B, Shaviklo AR, Aalami M. 2014. Leaching and heating process as alternative to produce fish protein powder from Kilka (Clupeonella cultiventris caspia. Nusantara Bioscience 6: 1-6. The effect of protein extraction procedures (leached mince and heated suspension on selected properties of fish protein powder (proximate composition, pH, color, density, viscosity, fat adsorption, emulsifying capacity, emulsifying stability, foaming capacity, foaming stability, WBC, protein solubility in water, hygroscopicity, Trichloroacetic acid (TCA-soluble peptides and free sulfhydryl groups was investigated. Results showed that Fish protein powder (FPP produced by leaching mince (LM have higher protein, moisture, ash, pH, L*, viscosity, emulsion capacity, emulsion stability, foam capacity, foam stability, water binding capacity (WBC, protein solubility, hygroscopicity, TCA soluble peptides and free sulfhydryl group content than heated suspension (HS (P0.05. Overall, it was observed that high temperature during heating of suspension in HS method makes possible protein denaturation and aggregation. Consequently, based on functional, chemical and physical properties, extraction of fish protein by leaching process was found to be suitable for the production of fish protein powder.

  20. A thermosyphon heat pipe cooler for high power LEDs cooling

    Science.gov (United States)

    Li, Ji; Tian, Wenkai; Lv, Lucang

    2016-08-01

    Light emitting diode (LED) cooling is facing the challenge of high heat flux more seriously with the increase of input power and diode density. The proposed unique thermosyphon heat pipe heat sink is particularly suitable for cooling of high power density LED chips and other electronics, which has a heat dissipation potential of up to 280 W within an area of 20 mm × 22 mm (>60 W/cm2) under natural air convection. Meanwhile, a thorough visualization investigation was carried out to explore the two phase flow characteristics in the proposed thermosyphon heat pipe. Implementing this novel thermosyphon heat pipe heat sink in the cooling of a commercial 100 W LED integrated chip, a very low apparent thermal resistance of 0.34 K/W was obtained under natural air convection with the aid of the enhanced boiling heat transfer at the evaporation side and the enhanced natural air convection at the condensation side.

  1. Silicon oxide based high capacity anode materials for lithium ion batteries

    Science.gov (United States)

    Deng, Haixia; Han, Yongbong; Masarapu, Charan; Anguchamy, Yogesh Kumar; Lopez, Herman A.; Kumar, Sujeet

    2017-03-21

    Silicon oxide based materials, including composites with various electrical conductive compositions, are formulated into desirable anodes. The anodes can be effectively combined into lithium ion batteries with high capacity cathode materials. In some formulations, supplemental lithium can be used to stabilize cycling as well as to reduce effects of first cycle irreversible capacity loss. Batteries are described with surprisingly good cycling properties with good specific capacities with respect to both cathode active weights and anode active weights.

  2. Present situation of heating enterpreneurship in Finland

    International Nuclear Information System (INIS)

    Solmio, H.

    1997-01-01

    Heating entrepreneurs are farmers, who usually have a wood-lot of their own, or entrepreneurs, who have undertaken to look after the supply of fuel to real estates and their heating. The TTS- Institute conducted an analysis of the scope of heating enterpreneurship in connection with the project belonging to the national Bioenergy Research Programme. According to the responses obtained in a mail questionnaire study conducted in autumns 1996, and other data obtained on the subject, there were 36 active heating entrepreneur sites in Finland in December 1996. Heating enterpreneurship, usually involving the supply of chipped wood, has become more common during the past few years. In 1994, it was started at ten places, in 1995 at eight places, and in 1996 at twelve places. The majority, nearly three quarters, of the heating enterpreneurship sites at the end of 1996 were school buildings and one fifth were district heating plants. The solid fuel boiler capacity of all the plants in the study was 11.5 MW. The district heating plants were 0.3-2.5 MW in capacity, the school buildings were in the 60-500 kW range, old peoples'' homes had capacities of 300-370 kW. Except for one school building using sod peat as primary fuel, wood chips was the primary fuel used by institutional buildings. The enterprise form was that of an entrepreneur or a pool formed by entrepreneurs in the case of 27 entrepreneurs, a company in the case of 6, and a co-operative society in the case of three. There were 56 heating-enterpreneurship sites at the implementation or planning stage. Four fifths of them involved heat generation capacity of less than 500 kW and one fifth a capacity of 0.5-2.0 Mw Tyoetehoseuran Metsaetiedote. 13 refs., 3 figs

  3. Cryogenic heat transfer

    CERN Document Server

    Barron, Randall F

    2016-01-01

    Cryogenic Heat Transfer, Second Edition continues to address specific heat transfer problems that occur in the cryogenic temperature range where there are distinct differences from conventional heat transfer problems. This updated version examines the use of computer-aided design in cryogenic engineering and emphasizes commonly used computer programs to address modern cryogenic heat transfer problems. It introduces additional topics in cryogenic heat transfer that include latent heat expressions; lumped-capacity transient heat transfer; thermal stresses; Laplace transform solutions; oscillating flow heat transfer, and computer-aided heat exchanger design. It also includes new examples and homework problems throughout the book, and provides ample references for further study.

  4. Crystalline-Amorphous Core−Shell Silicon Nanowires for High Capacity and High Current Battery Electrodes

    KAUST Repository

    Cui, Li-Feng

    2009-01-14

    Silicon is an attractive alloy-type anode material for lithium ion batteries because of its highest known capacity (4200 mAh/g). However silicon\\'s large volume change upon lithium insertion and extraction, which causes pulverization and capacity fading, has limited its applications. Designing nanoscale hierarchical structures is a novel approach to address the issues associated with the large volume changes. In this letter, we introduce a core-shell design of silicon nanowires for highpower and long-life lithium battery electrodes. Silicon crystalline- amorphous core-shell nanowires were grown directly on stainless steel current collectors by a simple one-step synthesis. Amorphous Si shells instead of crystalline Si cores can be selected to be electrochemically active due to the difference of their lithiation potentials. Therefore, crystalline Si cores function as a stable mechanical support and an efficient electrical conducting pathway while amorphous shells store Li ions. We demonstrate here that these core-shell nanowires have high charge storage capacity (̃1000 mAh/g, 3 times of carbon) with ̃90% capacity retention over 100 cycles. They also show excellent electrochemical performance at high rate charging and discharging (6.8 A/g, ̃20 times of carbon at 1 h rate). © 2009 American Chemical Society.

  5. Malone-brayton cycle engine/heat pump

    Science.gov (United States)

    Gilmour, Thomas A.

    1994-07-01

    A machine, such as a heat pump, and having an all liquid heat exchange fluid, operates over a more nearly ideal thermodynamic cycle by adjustment of the proportionality of the volumetric capacities of a compressor and an expander to approximate the proportionality of the densities of the liquid heat exchange fluid at the chosen working pressures. Preferred forms of a unit including both the compressor and the expander on a common shaft employs difference in axial lengths of rotary pumps of the gear or vane type to achieve the adjustment of volumetric capacity. Adjustment of the heat pump system for differing heat sink conditions preferably employs variable compression ratio pumps.

  6. Inverse Problem and Variation Method to Optimize Cascade Heat Exchange Network in Central Heating System

    Institute of Scientific and Technical Information of China (English)

    ZHANG Yin; WEI Zhiyuan; ZHANG Yinping; WANG Xin

    2017-01-01

    Urban heating in northern China accounts for 40% of total building energy usage.In central heating systems,heat is often transfened from heat source to users by the heat network where several heat exchangers arc installed at heat source,substations and terminals respectively.For given overall heating capacity and heat source temperarure,increasing the terminal fluid temperature is an effective way to improve the thermal performance of such cascade heat exchange network for energy saving.In this paper,the mathematical optimization model of the cascade heat exchange network with three-stage heat exchangers in series is established.Aim at maximizing the cold fluid temperature for given hot fluid temperature and overall heating capacity,the optimal heat exchange area distribution and the medium fluids' flow rates are determined through inverse problem and variation method.The preliminary results show that the heat exchange areas should be distributed equally for each heat exchanger.It also indicates that in order to improve the thernmal performance of the whole system,more heat exchange areas should be allocated to the heat exchanger where flow rate difference between two fluids is relatively small.This work is important for guiding the optimization design of practical cascade heating systems.

  7. Performance analysis of diesel engine heat pump incorporated with heat recovery

    International Nuclear Information System (INIS)

    Shah, N.N.; Huang, M.J.; Hewitt, N.J.

    2016-01-01

    Highlights: • Diesel engine heat pump with heat recovery. • Water-to-water source heat pump based on R134a. • Possibility for different flow temperature for heat distribution system. • Possible retrofit application in off-gas or weak electricity network area. • Potential to diversify use of fossil fuel, primary energy and CO_2 emission savings. - Abstract: This paper presents experimental study of diesel engine heat pump (DEHP) system to find potential as retrofit technology in off-gas or weak electricity network area to replace existing gas/oil/electric heating system in domestic sector. Test set-up of diesel engine driven water-to-water heat pump system was built which included heat recovery arrangement from the engine coolant & exhaust gas. The system was designed to meet typical house heating demand in Northern Ireland. Performance of DEHP was evaluated to meet house-heating demand at different flow temperature (35, 45, 55 & 65 °C), a typical requirement of underfloor space heating, medium/high temperature radiators and domestic hot water. The performance was evaluated against four-evaporator water inlet temperature (0, 5, 10 & 15 °C) and at three different engine speed 1600, 2000 & 2400 rpm. Experiment results were analysed in terms of heating/cooling capacity, heat recovery, total heat output, primary energy ratio (PER), isentropic efficiency, etc. Test results showed that DEHP is able to meet house-heating demand with help of heat recovery with reduced system size. Heat recovery contributed in a range of 22–39% in total heat output. It is possible to achieve high flow temperature in a range of 74 °C with help of heat recovery. Overall system PER varied in a range of 0.93–1.33. Speed increment and flow temperature has significant impact on heat recovery, total heat output and PER. A case scenario with different flow temperature to match house-heating demand has been presented to show working potential with different heat distribution system

  8. Evaluation of a dehumidifier with adsorbent coated heat exchangers for tropical climate operations

    KAUST Repository

    Oh, Seung Jin; Ng, Kim Choon; Chun, Wongee; Chua, Kian Jon Ernest

    2017-01-01

    This paper presents the evaluation of a solid desiccant dehumidifier equipped with adsorbent powder coated heat exchangers (PCHX). The main component of the solid desiccant dehumidifier includes two heat exchangers that are coated with silica gel RD type powders in order to increase water adsorption uptake by improving its heat and mass transfer. A series of experiment are conducted to evaluate two key performance indices, namely, moisture removal capacity (MRC) and thermal coefficient performance (COPth), under various hot and humid air conditions. Conventional granular adsorbent packed heat exchangers (GPHX) are employed to benchmark the performance of the adsorbent coated heat exchanger (PCHX). Results reveal that the PCHX exhibits higher uptake performance due to better heat and mass transfer. It is found that the moisture removal capacity increases from 7.4 g/kg to 11.0 g/kg with air flow rates of 35 kg/h, resulting in the extended contact time of the water vapor. Experiments also demonstrate that the moisture removal capacity is highly affected by inlet air humidity ratio. In addition, marked improvement in COPth can be achieved by a lowered hot water regeneration temperature.

  9. Evaluation of a dehumidifier with adsorbent coated heat exchangers for tropical climate operations

    KAUST Repository

    Oh, Seung Jin

    2017-03-10

    This paper presents the evaluation of a solid desiccant dehumidifier equipped with adsorbent powder coated heat exchangers (PCHX). The main component of the solid desiccant dehumidifier includes two heat exchangers that are coated with silica gel RD type powders in order to increase water adsorption uptake by improving its heat and mass transfer. A series of experiment are conducted to evaluate two key performance indices, namely, moisture removal capacity (MRC) and thermal coefficient performance (COPth), under various hot and humid air conditions. Conventional granular adsorbent packed heat exchangers (GPHX) are employed to benchmark the performance of the adsorbent coated heat exchanger (PCHX). Results reveal that the PCHX exhibits higher uptake performance due to better heat and mass transfer. It is found that the moisture removal capacity increases from 7.4 g/kg to 11.0 g/kg with air flow rates of 35 kg/h, resulting in the extended contact time of the water vapor. Experiments also demonstrate that the moisture removal capacity is highly affected by inlet air humidity ratio. In addition, marked improvement in COPth can be achieved by a lowered hot water regeneration temperature.

  10. Heat transfer from a high temperature condensable mixture

    International Nuclear Information System (INIS)

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

    1978-01-01

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

  11. Coupling heat and chemical tracer experiments for estimating heat transfer parameters in shallow alluvial aquifers.

    Science.gov (United States)

    Wildemeersch, S; Jamin, P; Orban, P; Hermans, T; Klepikova, M; Nguyen, F; Brouyère, S; Dassargues, A

    2014-11-15

    Geothermal energy systems, closed or open, are increasingly considered for heating and/or cooling buildings. The efficiency of such systems depends on the thermal properties of the subsurface. Therefore, feasibility and impact studies performed prior to their installation should include a field characterization of thermal properties and a heat transfer model using parameter values measured in situ. However, there is a lack of in situ experiments and methodology for performing such a field characterization, especially for open systems. This study presents an in situ experiment designed for estimating heat transfer parameters in shallow alluvial aquifers with focus on the specific heat capacity. This experiment consists in simultaneously injecting hot water and a chemical tracer into the aquifer and monitoring the evolution of groundwater temperature and concentration in the recovery well (and possibly in other piezometers located down gradient). Temperature and concentrations are then used for estimating the specific heat capacity. The first method for estimating this parameter is based on a modeling in series of the chemical tracer and temperature breakthrough curves at the recovery well. The second method is based on an energy balance. The values of specific heat capacity estimated for both methods (2.30 and 2.54MJ/m(3)/K) for the experimental site in the alluvial aquifer of the Meuse River (Belgium) are almost identical and consistent with values found in the literature. Temperature breakthrough curves in other piezometers are not required for estimating the specific heat capacity. However, they highlight that heat transfer in the alluvial aquifer of the Meuse River is complex and contrasted with different dominant process depending on the depth leading to significant vertical heat exchange between upper and lower part of the aquifer. Furthermore, these temperature breakthrough curves could be included in the calibration of a complex heat transfer model for

  12. Highly heat removing radiation shielding material

    International Nuclear Information System (INIS)

    Asano, Norio; Hozumi, Masahiro.

    1990-01-01

    Organic materials, inorganic materials or metals having excellent radiation shielding performance are impregnated into expanded metal materials, such as Al, Cu or Mg, having high heat conductivity. Further, the porosity of the expanded metals and combination of the expanded metals and the materials to be impregnated are changed depending on the purpose. Further, a plurality of shielding materials are impregnated into the expanded metal of the same kind, to constitute shielding materials. In such shielding materials, impregnated materials provide shielding performance against radiation rays such as neutrons and gamma rays, the expanded metals provide heat removing performance respectively and they act as shielding materials having heat removing performance as a whole. Accordingly, problems of non-informity and discontinuity in the prior art can be dissolved be provide materials having flexibility in view of fabrication work. (T.M.)

  13. Heat Transfer Modeling for Rigid High-Temperature Fibrous Insulation

    Science.gov (United States)

    Daryabeigi, Kamran; Cunnington, George R.; Knutson, Jeffrey R.

    2012-01-01

    Combined radiation and conduction heat transfer through a high-temperature, high-porosity, rigid multiple-fiber fibrous insulation was modeled using a thermal model previously used to model heat transfer in flexible single-fiber fibrous insulation. The rigid insulation studied was alumina enhanced thermal barrier (AETB) at densities between 130 and 260 kilograms per cubic meter. The model consists of using the diffusion approximation for radiation heat transfer, a semi-empirical solid conduction model, and a standard gas conduction model. The relevant parameters needed for the heat transfer model were estimated from steady-state thermal measurements in nitrogen gas at various temperatures and environmental pressures. The heat transfer modeling methodology was evaluated by comparison with standard thermal conductivity measurements, and steady-state thermal measurements in helium and carbon dioxide gases. The heat transfer model is applicable over the temperature range of 300 to 1360 K, pressure range of 0.133 to 101.3 x 10(exp 3) Pa, and over the insulation density range of 130 to 260 kilograms per cubic meter in various gaseous environments.

  14. Excess Molar Volume,Viscosity and Heat Capacity for the Mixture of 1,2—Propanediol—Water at Different Temperatures

    Institute of Scientific and Technical Information of China (English)

    杨长生; 马沛生; 唐多强; 靳凤民

    2003-01-01

    Experimental densities,viscosities and heat capacities at different emperatures were presented over the entire mole fraction range for the binary mixture of 1,2-propanediol and water,Density values were used in the determination of excess molar volumes,VE,At the same time,the excess viscosity was in vestigated,The values of VE and ηE were fitted to the Redlich-kister equation.Good agreement was observed,The excess volumes are negative over the entire range of composition.They show an U-shaped-concentration dependence and decrease in abolute values with increase of temperature,Values of ηE are negative over the entire range of the composition,and has a trend very similar to that of VE ,The analysis shows that at any temperature the specific heat of mixture is a linear function of the composition as x1>20%,All the extended lines intersect at one point.An empirical equation is obtained to calculate the specific heat to mixture at any composition and temperature in the experimental range.

  15. Energy Analysis of Cascade Heating with High Back-Pressure Large-Scale Steam Turbine

    Directory of Open Access Journals (Sweden)

    Zhihua Ge

    2018-01-01

    Full Text Available To reduce the exergy loss that is caused by the high-grade extraction steam of traditional heating mode of combined heat and power (CHP generating unit, a high back-pressure cascade heating technology for two jointly constructed large-scale steam turbine power generating units is proposed. The Unit 1 makes full use of the exhaust steam heat from high back-pressure turbine, and the Unit 2 uses the original heating mode of extracting steam condensation, which significantly reduces the flow rate of high-grade extraction steam. The typical 2 × 350 MW supercritical CHP units in northern China were selected as object. The boundary conditions for heating were determined based on the actual climatic conditions and heating demands. A model to analyze the performance of the high back-pressure cascade heating supply units for off-design operating conditions was developed. The load distributions between high back-pressure exhaust steam direct supply and extraction steam heating supply were described under various conditions, based on which, the heating efficiency of the CHP units with the high back-pressure cascade heating system was analyzed. The design heating load and maximum heating supply load were determined as well. The results indicate that the average coal consumption rate during the heating season is 205.46 g/kWh for the design heating load after the retrofit, which is about 51.99 g/kWh lower than that of the traditional heating mode. The coal consumption rate of 199.07 g/kWh can be achieved for the maximum heating load. Significant energy saving and CO2 emission reduction are obtained.

  16. Critical behaviour of binary mixture of {xC6H5CN + (1 - x)CH3(CH2)7CH3}: Measurements of coexistence curves, light scattering, and heat capacity

    International Nuclear Information System (INIS)

    Lei Yuntao; Chen Zhiyun; Wang Nong; Mao Chunfeng; An Xueqin; Shen Weiguo

    2010-01-01

    Liquid + liquid coexistence, light scattering, and isobaric heat capacity per unit volume for the critical solutions of (benzonitrile + n-nonane) have been measured. The critical exponents relating to the coexistence curve β, the osmotic compressibility γ, the correlation length ν, and the heat capacity α have been deduced and the values are consistent with the 3D-Ising values in the range close to the critical point. The experimental results of the liquid + liquid coexistence were analyzed to examine the Wegner correction terms and the behaviour of the diameter of the coexistence curves. The light scattering data were well described by the crossover model proposed by Anisimov and Sengers, and showed a tendency of monotonic crossover of the critical exponents γ and ν from the 3D-Ising values to the mean-field values as the temperature departures from the critical point. From calorimetric measurements, the amplitude A ± and the critical background B cr of the heat capacity in the critical region have been deduced and some universal ratios are tested.

  17. High-temperature industrial process heat: technology assessment and introduction rationale

    Energy Technology Data Exchange (ETDEWEB)

    1978-03-03

    Three specific topics of interest to DOE are addressed: to establish the significance and identify the role of high-temperature process heat in the nation's energy economy; to identify the role of solar thermal power in these high-temperature industrial applications in terms of possible markets and economic potential; and to recommend programmatic approaches for these solar thermal high-temperature process heat activities, including proposed content for initial Request for Proposals (RFPs) to accomplish such activities. The scope of the work required to accomplish these three purposes included the following: review of US industrial energy requirements, survey of current DOE low-temperature Agricultural and Industrial Process Heat Program, examination of high-temperature solar thermal electric systems already developed or under development by DOE and industry, and coordination with the high-energy user segments of industry (i.e., cement, chemical and petroleum) to find additional markets for some or all of the systems or components being developed in the DOE solar thermal electric program. Statistical data are presented identifying energy allocations to process heat and defining DOE's involvement. Three current fossil fuel process heat system examples are provided and the corresponding solar potential is identified.

  18. CASTOR {sup registered} HAW28M - a high heat load cask for transport and storage of vitrified high level waste containers

    Energy Technology Data Exchange (ETDEWEB)

    Vossnacke, A.; Klein, K.; Kuehne, B. [GNS Gesellschaft fuer Nuklear-Service mbH/GNB, Essen (Germany)

    2004-07-01

    Within the German return programme for vitrified high level waste (HLW) from reprocessing at COGEMA and BNFL up to now 39 casks loaded with 28 containers each were transported back to Germany and are stored in the Interim Storage Facility Gorleben (TBL-G) for up to 40 years. For transport and storage in all but one case the GNB casks CASTOR {sup registered} HAW 20/28 CG have been used. This cask type is designed to accommodate 20 or 28 HLW containers with a total thermal power of 45 kW maximum. In the near future, among the high level waste, which has to be returned to Germany, there will be an increasing number of containers of which the heat capacity and radioactive inventory will exceed the technical limits of the CASTOR {sup registered} HAW 20/28 CG. Therefore GNB has started the development of a new cask generation, named CASTOR {sup registered} HAW28M, meeting these future requirements. The CASTOR {sup registered} HAW28M is especially developed for the transport of vitrified residues from France and Great Britain to Germany. It complies with the international regulations for type B packages according to IAEA (International Atomic Energy Agency). It is thus guaranteed that even in case of any accident the cask body and the lid system remain functional and the safe confinement of the radioactive contents remains intact during transport. The CASTOR {sup registered} HAW28M fulfills not only the requirements for transport but also the acceptance criteria of interim storage: radiation shielding, heat dissipation, safe confinement under both normal and hypothetical accident conditions. Storage buildings such as the TBL-G simply support the safety functions of the cask. The challenge for the development results from higher requirements of the technical specification, particularly related to fuel which is reprocessed. As a consequence of the reprocessing of fuel with increased enrichment and burn up, higher heat capacity and sophisticated shielding measures have to be

  19. Reconstruction actions carried out in order to achieve nominal design heat capacity of hot water boilers type VKSM 40; A product of TPK-Zagreb

    International Nuclear Information System (INIS)

    Ninevski, Gjorgji; Sekovanikj, Ivica

    2000-01-01

    Hot water boilers with a steep turbines membranous produced by TPK-Zagreb in 1979 are projected for nominal capacity of 46.52 MW. But it was demonstrated in practice, according the performed measurements, that during the exploitation they do not give declared thermal power. In this article the chronological review of all successful performed reconstructive operations by engineering staff from Toplifikacija Joint-Stock Co. for district heating -Skopje (Macedonia) on the hot water boilers type VKSM40 with nominal capacity of 46.52 MW is given. (Authors)

  20. Theoretical energy and exergy analyses of solar assisted heat pump space heating system

    Directory of Open Access Journals (Sweden)

    Atmaca Ibrahim

    2014-01-01

    Full Text Available Due to use of alternative energy sources and energy efficient operation, heat pumps come into prominence in recent years. Especially in solar-assisted heat pumps, sizing the required system is difficult and arduous task in order to provide optimum working conditions. Therefore, in this study solar assisted indirect expanded heat pump space heating system is simulated and the results of the simulation are compared with available experimental data in the literature in order to present reliability of the model. Solar radiation values in the selected region are estimated with the simulation. The case study is applied and simulation results are given for Antalya, Turkey. Collector type and storage tank capacity effects on the consumed power of the compressor, COP of the heat pump and the overall system are estimated with the simulation, depending on the radiation data, collector surface area and the heating capacity of the space. Exergy analysis is also performed with the simulation and irreversibility, improvement potentials and exergy efficiencies of the heat pump and system components are estimated.