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Sample records for high heat capacity

  1. High-Capacity Heat-Pipe Evaporator

    Science.gov (United States)

    Oren, J. A.; Duschatko, R. J.; Voss, F. E.; Sauer, L. W.

    1989-01-01

    Heat pipe with cylindrical heat-input surface has higher contact thermal conductance than one with usual flat surface. Cylindrical heat absorber promotes nearly uniform flow of heat into pipe at all places around periphery of pipe, helps eliminate hotspots on heat source. Lugs in aluminum pipe carry heat from outer surface to liquid oozing from capillaries of wick. Liquid absorbs heat, evaporates, and passes out of evaporator through interlug passages.

  2. Heat capacity measurements on high T sub c superconductors

    CERN Document Server

    Oezcan, S

    1998-01-01

    temperature interval. The phase transition jump increases with the increasing of oxygen amount in the CuO sub 2 layers. The hight of the jump is varying from 1.5% to 3.5% of the total specific heat which is the nature of the bulk superconductivity. The small coherence length increases fluctuation effects and also causes the dependence of superconducting properties on structural defects. The fluctuation effects on the heat capacity of YBCO is investigated on the sample that shows clear superconducting properties. In this work, a heat capacity measurement system which has high sensitivity and reproducibility designed and constructed. The investigation of the effect of oxygen stoichiometry on the superconducting properties of high T sub c superconductors was aimed. For this purpose electrical resistivity, magnetic susceptibility and heat capacity experiment were performed. The constructed system is a computerized adiabatic calorimeter which has temperature resolution of about 0.1 mk and operates in the temperatu...

  3. Development of a high capacity variable conductance heat pipe.

    Science.gov (United States)

    Kosson, R.; Hembach, R.; Edelstein, F.; Loose, J.

    1973-01-01

    The high-capacity, pressure-primed, tunnel-artery wick concept was used in a gas-controlled variable conductance heat pipe. A variety of techniques were employed to control the size of gas/vapor bubbles trapped within the artery. Successful operation was attained with a nominal 6-foot long, 1-inch diameter cold reservoir VCHP using ammonia working fluid and nitrogen control gas. The pipe contained a heat exchanger to subcool the liquid in the artery. Maximum transport capacity with a 46-inch effective length was 1200 watts level (more than 50,000 watt-inches) and 800 watts at 0.5-inch adverse tilt.

  4. 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.

  5. Investigation of high capacity heat energy storage for building applications

    OpenAIRE

    Ding, Yate

    2014-01-01

    The problems of excessive consumption of fossil resources, oil shortages and greenhouse gas emissions are becoming increasingly severe. Research and development work on new methods of thermal energy storage are imminently required. To effectively store seasonal renewable energy, a novel high capacity heat storage system has been designed and evaluated/validated through laboratory experiments and numerical simulations in this research. The system is driven by direct flow evacuated tube solar c...

  6. High capacity demonstration of honeycomb panel heat pipes

    Science.gov (United States)

    Tanzer, H. J.

    1989-01-01

    The feasibility of performance enhancing the sandwich panel heat pipe was investigated for moderate temperature range heat rejection radiators on future-high-power spacecraft. The hardware development program consisted of performance prediction modeling, fabrication, ground test, and data correlation. Using available sandwich panel materials, a series of subscale test panels were augumented with high-capacity sideflow and temperature control variable conductance features, and test evaluated for correlation with performance prediction codes. Using the correlated prediction model, a 50-kW full size radiator was defined using methanol working fluid and closely spaced sideflows. A new concept called the hybrid radiator individually optimizes heat pipe components. A 2.44-m long hybrid test vehicle demonstrated proof-of-principle performance.

  7. Transient response of a high-capacity heat pipe for Space Station Freedom

    Science.gov (United States)

    Ambrose, J. H.; Holmes, H. R.

    1991-01-01

    High-capacity heat pipe radiator panels have been proposed as the primary means of heat rejection for Space Station Freedom. In this system, the heat pipe would interface with the thermal bus condensers. Changes in system heat load can produce large temperature and heat load variations in individual heat pipes. Heat pipes could be required to start from an initially cold state, with heat loads temporarily exceeding their low-temperature transport capacity. The present research was motivated by the need for accurate prediction of such transient operating conditions. In this work, the cold startup of a 6.7-meter long high-capacity heat pipe is investigated experimentally and analytically. A transient thermohydraulic model of the heat pipe was developed which allows simulation of partially-primed operation. The results of cold startup tests using both constant temperature and constant heat flux evaporator boundary conditions are shown to be in good agreement with predicted transient response.

  8. Droplet Evaporator For High-Capacity Heat Transfer

    Science.gov (United States)

    Valenzuela, Javier A.

    1993-01-01

    Proposed heat-exchange scheme boosts heat transfer per unit area. Key component is generator that fires uniform size droplets of subcooled liquid at hot plate. On impact, droplets spread out and evaporate almost instantly, removing heat from plate. In practice, many generator nozzles arrayed over evaporator plate.

  9. 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.

  10. Thermal analysis method of high capacity communications satellite with heat pipes

    Science.gov (United States)

    Tsunoda, Hiroaki; Nakajima, Katsuhiko; Miyasaka, Akihiro

    Thermal analysis method for heat pipe embedded communications equipment panel is treated in this paper. The main problem of the thermal analysis is how to construct the mathematical model under the limitation of computer CPU memory size. The mathematical model for the heat pipe embedded panel is first established based on the experiments. The essence of this method is to divide panel area into several small regions and perform thermal analysis independently using the fact of low thermal conductivity of honeycomb sandwich panel. To check the correctness of this method, the experiment using the test panel which thermally simulates the north communications equipment panel of two-ton class high capacity communications satellite has been conducted. The experiment shows the method works well.

  11. The Magnetocaloric Effect and Heat Capacity of Suspensions of High-Dispersity Samarium Ferrite

    Science.gov (United States)

    Korolev, V. V.; Aref'ev, I. M.; Ramazanova, A. G.

    2008-02-01

    The magnetocaloric effect and specific heat capacity of an aqueous suspension of samarium ferrite were determined calorimetrically over the temperature range 288-343 K in magnetic fields of 0-0.7 T. The data obtained were used to calculate changes in the magnetic component of the molar heat capacity and entropy of the magnetic phase and changes in the enthalpy of the process under an applied magnetic field. The magnetocaloric effect was found to increase nonlinearly as the magnetic field induction grew. The corresponding temperature dependences contained a maximum at 313 K related to the second-order magnetic phase transition at the Curie point. The field and temperature dependences of heat capacity contained a maximum in fields of 0.4 T and a minimum at the magnetic phase transition temperature.

  12. High-temperature heat capacity of CdO-V2O5 oxides

    Science.gov (United States)

    Denisova, L. T.; Chumilina, L. G.; Belousova, N. V.; Denisov, V. M.; Galiakhmetova, N. A.

    2017-12-01

    Vanadates Cd2V2O7 and CdV2O6 have been prepared from CdO i V2O5 by three-phase synthesis with subsequent burning at 823-1073 K and 823-853 K, respectively. The molar heat capacity of these oxide compounds has been measured by differential scanning calorimetry. The enthalpy change, the entropy change, and the reduced Gibbs energy are calculated using the experimental dependences C p = f( T). It is shown that there is a correlation between the specific heat capacity and the composition of CdO-V2O5 oxide system.

  13. High-temperature heat capacity of samarium and erbium titanates with pyrochlore structure

    Science.gov (United States)

    Denisova, L. T.; Chumilina, L. G.; Denisov, V. M.; Ryabov, V. V.

    2017-12-01

    Titanates Sm2Ti2O7 and Er2Ti2O7 with pyrochlore structure have been prepared by solid-phase synthesis in air from stoichiometric Sm2O3 (Er2O3)-TiO2 mixtures sequentially at 1673 and 1773 K. Hightemperature heat capacity of the oxide compounds has been determined by differential scanning calorimetry. Their thermodynamic properties have been calculated from experimental temperature dependence C p = f( T).

  14. Heat capacity and heat of dissociation of methane hydrates

    Energy Technology Data Exchange (ETDEWEB)

    Rueff, R.M.; Sloan, E.D.; Yesavage, V.F.

    1988-09-01

    The objective of this study was to determine the heat capacity and heat of dissociation of methane hydrates. A technique has been devised which circumvents the two major problems encountered in measuring gas hydrate heat capacity: the need to impose a mechanical pressure during the measurement and the need to have an absolutely pure hydrate sample. The technique was shown to be successful utilizing high-pressure, constant-volume cells in a differential scanning calorimeter.

  15. 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.

  16. 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...

  17. Heat capacity of spinning plasma

    Science.gov (United States)

    Geyko, V. I.; Fisch, N. J.

    2017-10-01

    Equilibrium thermodynamics properties, such as heat capacity and adiabatic axial and radial compressibility of a rotating plasma column are studied. These properties depend on rotation speed, charge density, external magnetic field strength and electron-ion mass ratio. Plasma rotation serves as an additional energy storage, hence, yields to increased heat capacity. It also leads to charge separation that changes plasma density distribution due to electrostatic interaction and Lorentz force and therefore modifies thermodynamic properties. The obtained results can provide limits and optimal regimes for radial compression of z-pinch type structures and optimize energy deposition profile. This work was supported by NNSA DE-NA0001836 and DE-NA0002948 and by NSF Contract No. PHY-1506122.

  18. Multiple pulse-heating experiments with different current to determine total emissivity, heat capacity, and electrical resistivity of electrically conductive materials at high temperatures

    Science.gov (United States)

    Watanabe, Hiromichi; Yamashita, Yuichiro

    2012-01-01

    A modified pulse-heating method is proposed to improve the accuracy of measurement of the hemispherical total emissivity, specific heat capacity, and electrical resistivity of electrically conductive materials at high temperatures. The proposed method is based on the analysis of a series of rapid resistive self-heating experiments on a sample heated at different temperature rates. The method is used to measure the three properties of the IG-110 grade of isotropic graphite at temperatures from 850 to 1800 K. The problem of the extrinsic heating-rate effect, which reduces the accuracy of the measurements, is successfully mitigated by compensating for the generally neglected experimental error associated with the electrical measurands (current and voltage). The results obtained by the proposed method can be validated by the linearity of measured quantities used in the property determinations. The results are in reasonably good agreement with previously published data, which demonstrate the suitability of the proposed method, in particular, to the resistivity and total emissivity measurements. An interesting result is the existence of a minimum in the emissivity of the isotropic graphite at around 1120 K, consistent with the electrical resistivity results.

  19. 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.

  20. High-Performance Heat Pipe

    Science.gov (United States)

    Alario, J. P.; Kosson, R.; Haslett, R.

    1985-01-01

    Single vapor channel and single liquid channel joined by axial slot. New design, permits high heat-transport capacity without excessively reducing heat-transfer efficiency. Contains two large axial channels, one for vapor and one for liquid, permitting axial transport and radial heat-transfer requirements met independently. Heat pipe has capacity of approximately 10 to sixth power watt-inches (2.5 X 10 to sixth power watt-cm) orders of magnitude greater than heat capacity of existing heat pipes. Design has high radial-heat-transfer efficiency, structurally simple, and has large liquid and vapor areas.

  1. Zeolite Y adsorbents with high vapor uptake capacity and robust cycling stability for potential applications in advanced adsorption heat pumps

    Energy Technology Data Exchange (ETDEWEB)

    Li, XS; Narayanan, S; Michaelis, VK; Ong, TC; Keeler, EG; Kim, H; Mckay, IS; Griffin, RG; Wang, EN

    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 Mg2+ 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 lab-scale 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, Al-27/Si-29 MAS NMR spectroscopy, ICP-AES, dynamic vapor sorption, SEM, Fick's 2nd law and D-R equation regressions. Among these, close examination of sorption isotherms for H2O 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. (C) 2014 Elsevier Inc. All rights reserved.

  2. The magnetocaloric effect and heat capacity of ferrimagnetic nanosystems: High-dispersity magnetite

    Science.gov (United States)

    Korolev, V. V.; Aref'ev, I. M.; Ramazanova, A. G.

    2007-06-01

    The magnetocaloric effects of aqueous and ethanolic high-dispersity magnetite suspensions and the magnetite magnetic liquid were determined calorimetrically over the temperature range 15-80°C. The temperature dependence of the magnetocaloric effect of suspensions was evidence of the thermal oxidation of magnetite to maghemite. The temperature dependences of the magnetocaloric effect of the magnetic liquid passed extrema related to the second-order magnetic phase transition.

  3. Preliminary phase relations involving glaucophane and applications to high pressure petrology: new heat capacity and thermodynamic data

    Science.gov (United States)

    Holland, Timothy J. B.

    1988-05-01

    New heat capacity measurements and cell volume data are presented for a very magnesian glaucophane from a Tauern Window eclogite. These data are combined with estimated entropy, thermal expansion, and compressibility data to generate an enthalpy of formation for glaucophane from experimentally determined phase equilibria. The data are supported by preliminary experiments of the author and provide consistent calculations on the pressure of formation of the Tauern eclogites and on the position of the blueschist-greenschist transformation reaction as studied experimentally by Maruyama et al. (1986). The resulting thermodynamic data for glaucophane may be combined with the dataset of Holland and Powell (1985) to calculate phase relations for blueschists and eclogites. The stability of magnesian glaucophane lies in the pressure range between 8 and 32 kbars at 400° C and between 13 and 33 kbars at 600° C, and the unusual eclogite assemblage of glaucophane+kyanite from the Tauern Window is restricted to pressures above 20 kbars at high water activity.

  4. Heat Capacity Mapping Mission: 1978-1980

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — NASA's Heat Capacity Mapping Mission (HCMM) project collected Earth data in the visible and thermal bands between April 1978 and September 1980. This was an...

  5. Device for Measuring Heat Capacities of Microcalorimeter Absorber Materials

    Science.gov (United States)

    Kotsubo, Vincent; Beall, James; Ullom, Joel

    2009-12-01

    We are developing a device for measuring the heat capacity of candidate absorber materials for gamma-ray microcalorimeters with the goal of finding materials with low heat capacity and high stopping power to improve detector efficiency. To date, only Sn has been effective as an absorber, and speculation is that other materials suffer from anomalously high heat capacities at low temperatures. The key component of the measurement device is a 17 mm×17 mm low heat capacity silicon platform suspended by Kevlar fibers designed for accepting 1 g to 2 g samples, and whose heat capacity can be characterized prior to attaching a sample. The platform has a thin film Pd/Au heater deposited directly on the silicon, and a semiconducting thermometer bonded to the surface. The heat capacity is determined from C = Gτ, where G is the in-situ measured conductance and x is the measured temperature decay time from a step change in applied heat. For a platform without samples, decay periods on the order of 0.3 to 0.05 seconds were measured. With samples, decay periods of several seconds are projected, allowing good resolution of the heat capacities. Several thermometers were tested in an effort to find one with the optimum characteristics for measuring platform temperatures. These included a commercial thick-film Ruthenium-oxide surface-mount resistor, a germanium NTD, and a zirconium oxy-nitride thin-film thermometer.

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

    Energy Technology Data Exchange (ETDEWEB)

    Hawkes, A.D. [Centre for Energy Policy and Technology, Imperial College London, Exhibition Road, London SW7 2AZ (United Kingdom); Leach, M.A. [Centre for Environmental Strategy, Faculty of Engineering, University of Surrey, Guildford GU2 7XH (United Kingdom)

    2008-04-15

    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. (author)

  7. On the Specific Heat Capacity of CuO Nanofluid

    OpenAIRE

    Le-Ping Zhou; Bu-Xuan Wang; Xiao-Feng Peng; Xiao-Ze Du; Yong-Ping Yang

    2010-01-01

    This paper reviews briefly the definition of heat capacity and clarifies the defined specific heat capacity and volumetric heat capacity. The specific heat capacity and volumetric heat capacity, with our measured experimental data for CuO nanofluids, are discussed as an illustrating example. The result indicates that the specific heat capacity of CuO nanofluid decreases gradually with increasing volume concentration of nanoparticles. The measurement and the prediction from the thermal equilib...

  8. Meteorite heat capacities: Results to date

    Science.gov (United States)

    Consolmagno, G.; Macke, R.; Britt, D.

    2014-07-01

    Heat capacity is an essential thermal property for modeling asteroid internal metamorphism or differentiation, and dynamical effects like YORP or Yarkovsky perturbations. We have developed a rapid, inexpensive, and non-destructive method for measuring the heat capacity of meteorites at low temperature [1]. A sample is introduced into a dewar of liquid nitrogen and an electronic scale measures the amount of nitrogen boiled away as the sample is cooled from the room temperature to the liquid nitrogen temperature; given the heat of vaporization of liquid nitrogen, one can then calculate the heat lost from the sample during the cooling process. Note that heat capacity in this temperature range is a strong function of temperature, but this functional relation is essentially the same for all materials; the values we determine are equivalent to the heat capacity of the sample at 175 K. To correct for systematic errors, samples of laboratory-grade quartz are measured along with the meteorite samples. To date, more than 70 samples of more than 50 different meteorites have been measured in this way, including ordinary chondrites [1], irons [2], basaltic achondrites [3], and a limited number of carbonaceous chondrites [1]. In general, one can draw a number of important conclusions from these results. First, the heat capacity of a meteorite is a function of its mineral composition, independent of shock, metamorphism, or other physical state. Second, given this relation, heat capacity can be strongly altered by terrestrial weathering. Third, the measurement of heat capacity in small (less than 1 g) samples as done typically by commercial systems runs a serious risk of giving misleading results for samples that are heterogeneous on scales of tens of grams or more. Finally, we demonstrate that heat capacity is a useful tool for determining and classifying a sample, especially if used in conjunction with other intrinsic variables such as grain density and magnetic susceptibility

  9. Residential Variable-Capacity Heat Pumps Sized to Heating Loads

    Energy Technology Data Exchange (ETDEWEB)

    Munk, Jeffrey D. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Jackson, Roderick K. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Odukomaiya, Adewale [Georgia Inst. of Technology, Atlanta, GA (United States); Gehl, Anthony C. [Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)

    2014-01-01

    Variable capacity heat pumps are an emerging technology offering significant energy savings potential and improved efficiency. With conventional single-speed systems, it is important to appropriately size heat pumps for the cooling load as over-sizing would result in cycling and insufficient latent capacity required for humidity control. These appropriately sized systems are often under-sized for the heating load and require inefficient supplemental electric resistance heat to meet the heating demand. Variable capacity heat pumps address these shortcomings by providing an opportunity to intentionally size systems for the dominant heating season load without adverse effects of cycling or insufficient dehumidification in the cooling season. This intentionally-sized system could result in significant energy savings in the heating season, as the need for inefficient supplemental electric resistance heat is drastically reduced. This is a continuation of a study evaluating the energy consumption of variable capacity heat pumps installed in two unoccupied research homes in Farragut, a suburb of Knoxville, Tennessee. In this particular study, space conditioning systems are intentionally sized for the heating season loads to provide an opportunity to understand and evaluate the impact this would have on electric resistance heat use and dehumidification. The results and conclusions drawn through this research are valid and specific for portions of the Southeastern and Midwestern United States falling in the mixed-humid climate zone. While other regions in the U.S. do not experience this type of climate, this work provides a basis for, and can help understand the implications of other climate zones on residential space conditioning energy consumption. The data presented here will provide a framework for fine tuning residential building EnergyPlus models that are being developed.

  10. 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.

  11. 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.

  12. CSTI High Capacity Power

    Science.gov (United States)

    Winter, Jerry 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.

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

    Science.gov (United States)

    Soltani, Z; Ziaie, F; Ghaffari, M; Beigzadeh, A M

    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 10MeV electron beam at doses of 75 to 250kGy. 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. Copyright © 2016 Elsevier B.V. All rights reserved.

  14. Hybrid heat capacity-moving slab solid-state laser

    Science.gov (United States)

    Stappaerts, Eddy A.

    2005-03-01

    Laser material is pumped and its stored energy is extracted in a heat capacity laser mode at a high duty factor. When the laser material reaches a maximum temperature, it is removed from the lasing region and a subsequent volume of laser material is positioned into the lasing region to repeat the lasing process. The heated laser material is cooled passively or actively outside the lasing region.

  15. Thermal management of instruments on space platforms using a high capacity two-phase heat transport system

    Science.gov (United States)

    Ollendorf, S.; Fowle, A.; Almgren, D.

    1981-01-01

    A system utilizing a pumped, two-phase single component working fluid for heat exchange and transport services necessary to meet the temperature control requirements of typical orbiting instrument payloads on space platforms is described. The design characteristics of the system is presented, together with a presentation of a laboratory apparatus for demonstration of proof of concept. Results indicate that the pumped two-phase design concept can meet a wide range of thermal performance requirements with the only penalty being the requirement for a small liquid pump.

  16. Heat capacity changes in carbohydrates and protein-carbohydrate complexes.

    Science.gov (United States)

    Chavelas, Eneas A; García-Hernández, Enrique

    2009-05-13

    Carbohydrates are crucial for living cells, playing myriads of functional roles that range from being structural or energy-storage devices to molecular labels that, through non-covalent interaction with proteins, impart exquisite selectivity in processes such as molecular trafficking and cellular recognition. The molecular bases that govern the recognition between carbohydrates and proteins have not been fully understood yet. In the present study, we have obtained a surface-area-based model for the formation heat capacity of protein-carbohydrate complexes, which includes separate terms for the contributions of the two molecular types. The carbohydrate model, which was calibrated using carbohydrate dissolution data, indicates that the heat capacity contribution of a given group surface depends on its position in the saccharide molecule, a picture that is consistent with previous experimental and theoretical studies showing that the high abundance of hydroxy groups in carbohydrates yields particular solvation properties. This model was used to estimate the carbohydrate's contribution in the formation of a protein-carbohydrate complex, which in turn was used to obtain the heat capacity change associated with the protein's binding site. The model is able to account for protein-carbohydrate complexes that cannot be explained using a previous model that only considered the overall contribution of polar and apolar groups, while allowing a more detailed dissection of the elementary contributions that give rise to the formation heat capacity effects of these adducts.

  17. Effect of Heat Treatment on the Nitrogen Content and Its Role on the Carbon Dioxide Adsorption Capacity of Highly Ordered Mesoporous Carbon Nitride.

    Science.gov (United States)

    Lakhi, Kripal S; Park, Dae-Hwan; Joseph, Stalin; Talapaneni, Siddulu N; Ravon, Ugo; Al-Bahily, Khalid; Vinu, Ajayan

    2017-03-02

    Mesoporous carbon nitrides (MCNs) with rod-shaped morphology and tunable nitrogen contents have been synthesized through a calcination-free method by using ethanol-washed mesoporous SBA-15 as templates at different carbonization temperatures. Carbon tetrachloride and ethylenediamine were used as the sources of carbon and nitrogen, respectively. The resulting MCN materials were characterized with low- and high-angle powder XRD, nitrogen adsorption, high-resolution (HR) SEM, HR-TEM, elemental analysis, X-ray photoelectron spectroscopy, and X-ray absorption near-edge structure techniques. The carbonization temperature plays a critical role in controlling not only the crystallinity, but also the nitrogen content and textural parameters of the samples, including specific surface area and specific pore volume. The nitrogen content of MCN decreases with a concomitant increase in specific surface area and specific pore volume, as well as the crystallinity of the samples, as the carbonization temperature is increased. The results also reveal that the structural order of the materials is retained, even after heat treatment at temperatures up to 900 °C with a significant reduction of the nitrogen content, but the structure is partially damaged at 1000 °C. The carbon dioxide adsorption capacity of these materials is not only dependent on the textural parameters, but also on the nitrogen content. The MCN prepared at 900 °C, which has an optimum BET surface area and nitrogen content, registers a carbon dioxide adsorption capacity of 20.1 mmol g(-1) at 273 K and 30 bar, which is much higher than that of mesoporous silica, MCN-1, activated carbon, and multiwalled carbon nanotubes. © 2017 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.

  18. The monogroove high performance heat pipe

    Science.gov (United States)

    Alario, J.; Haslett, R.; Kosson, R.

    1981-06-01

    The development of the monogroove heat pipe, a fundamentally new high-performance device suitable for multi-kilowatt space radiator heat-rejection systems, is reported. The design separates heat transport and transfer functions, so that each can be separately optimized to yield heat transport capacities on the order of 25 kW/m. Test versions of the device have proven the concept of heat transport capacity control by pore dimensions and the permeability of the circumferential wall wick structure, which together render it insensitive to tilt. All cases tested were for localized, top-side heat input and cooling and produced results close to theoretical predictions.

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

    Energy Technology Data Exchange (ETDEWEB)

    Thome, David Keith [Iowa State Univ., Ames, IA (United States)

    1977-10-01

    The heat capacity of high purity electrotransport refined lutetium was measured between 1 and 20°K. Results for thetaD 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 to about 11.3 mJ/g-atom-K2 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°K for samples with 0.1 to 1.5 atomic percent hydrogen. This accounts for a large amount of scatter in thetaD versus hydrogen content in this range. The heat capacity of a bulk sample of lutetium dihydride was measured between 1 and 20°K and showed a large increase in thetaD and a large decrease in ..gamma.. compared to pure lutetium.

  20. Electron heat capacity and lattice properties of Americium

    Science.gov (United States)

    Povzner, A. A.; Filanovich, A. N.; Os'kina, V. A.; Volkov, A. G.

    2013-12-01

    The temperature dependence of the electron heat capacity of americium is calculated using the concepts on the electronic structure and magnetic properties of this element. The Debye temperature, the thermal expansion coefficient, and the bulk modulus of americium are determined on the basis of the results of calculations and experimental data on heat capacity.

  1. Temperature dependence of electronic heat capacity in Holstein model of DNA

    Science.gov (United States)

    Fialko, N.; Sobolev, E.; Lakhno, V.

    2016-04-01

    The dynamics of charge migration was modeled to calculate temperature dependencies of its thermodynamic equilibrium values such as energy and electronic heat capacity in homogeneous adenine fragments. The energy varies from nearly polaron one at T ∼ 0 to midpoint of the conductivity band at high temperatures. The peak on the graph of electronic heat capacity is observed at the polaron decay temperature.

  2. How to Measure Heat Capacity at Low Temperatures

    Science.gov (United States)

    Ventura, Guglielmo; Perfetti, Mauro

    This chapter is devoted to the description of calorimetric techniques used to measure heat capacity of solids: pulse heat calorimetry (Sect. 2.3), relaxation calorimetry (Sect. 2.4), dual slope calorimetry (Sect. 2.5), a.c. calorimetry (Sect. 2.6), differential scanning calorimetry (Sect. 2.7). Examples of measurements of heat capacity are reported in Sects. 2.3 and 2.4.

  3. Heat-capacity measurements on small samples: The hybrid method

    NARCIS (Netherlands)

    Klaasse, J.C.P.; Brück, E.H.

    2008-01-01

    A newly developed method is presented for measuring heat capacities on small samples, particularly where thermal isolation is not sufficient for the use of the traditional semiadiabatic heat-pulse technique. This "hybrid technique" is a modification of this heat-pulse method in case the temperature

  4. High capacity carbon dioxide sorbent

    Energy Technology Data Exchange (ETDEWEB)

    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.

  5. High heat flux single phase heat exchanger

    Science.gov (United States)

    Valenzuela, Javier A.; Izenson, Michael G.

    1990-01-01

    This paper presents the results obtained to date in a program to develop a high heat flux, single-phase heat exchanger for spacecraft thermal management. The intended application is a net generation interface heat exchanger to couple the crew module water thermal bus to the two-phase ammonia main thermal bus in the Space Station Freedom. The large size of the interface heat exchanger is dictated by the relatively poor water-side heat transfer characteristics. The objective of this program is to develop a single-phase heat transfer approach which can achieve heat fluxes and heat transfer coefficients comparable to those of the evaporation ammonia side. A new heat exchanger concept has been developed to meet these objecties. The main feature of this heat exchanger is that it can achieve very high heat fluxes with a pressure drop one to two orders of magnitude lower than those of previous microchannel or jet impingement high heat flux heat exchangers. This paper describes proof-of-concept experiments performed in air and water and presents analytical model of the heat exchanger.

  6. Saturated-liquid heat capacity calculation of alkanes

    Directory of Open Access Journals (Sweden)

    JOVAN D. JOVANOVIC

    2005-12-01

    Full Text Available An empirical model for the calculation of the heat capacity of alkanes is recommended. This model was tested and compared to known models (Luria–Benson and Rizicka–Domalski using 68 sets with 1155 literature experimental heat capacity data of 39 alkanes. The obtained results indicate that the newmodel is slightly better tha the existing models, especially near the critical point.

  7. The high-temperature heat capacity of the (Th,U)O2 and (U,Pu)O2 solid solutions

    Science.gov (United States)

    Vălu, S. O.; Beneš, O.; Manara, D.; Konings, R. J. M.; Cooper, M. W. D.; Grimes, R. W.; Guéneau, C.

    2017-02-01

    The enthalpy increment data for the (Th,U)O2 and (U,Pu)O2 solid solutions are reviewed and complemented with new experimental data (400-1773 K) and many-body potential model simulations. The results of the review show that from room temperature up to about 2000 K the enthalpy data are in agreement with the additivity rule (Neumann-Kopp) in the whole composition range. Above 2000 K the effect of Oxygen Frenkel Pair (OFP) formation leads to an excess enthalpy (heat capacity) that is modeled using the enthalpy and entropy of OFP formation from the end-members. A good agreement with existing experimental work is observed, and a reasonable agreement with the results of the many-body potential model, which indicate the presence of the diffuse Bredig (superionic) transition that is not found in the experimental enthalpy increment data.

  8. 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.

  9. Heat capacity of GdNi sub 5

    Energy Technology Data Exchange (ETDEWEB)

    Szewczyk, A. (Inst. of Physics, Polish Academy of Sciences, Warsaw (Poland)); Radwanski, R.J.; Franse, J.J.M.; Nakotte, H. (Natuurkundig Lab., Univ. van Amsterdam (Netherlands))

    1992-02-01

    The heat capacity of GdNi{sub 5} was measured from 1.3 to 48 K in a fixed magnetic field (up to 5 T). The electronic, phonon, and magnetic contributions were separated. Temperature dependences of magnetic specific heat and entropy were calculated in the molecular field approximation. They are in good agreement with the experimental results. (orig.).

  10. Separation of Power and Capacity In latent Heat Energy Storage

    OpenAIRE

    Pointner, H.; Steinmann, W.D.; van Eck, M.; Bachelier, C.

    2015-01-01

    The state-of-the-art latent heat energy storage system is equipped with aluminum fins at the heat exchanger pipes in order to compensate the low thermal conductivity of the phase change material (PCM). The necessary amount of fins is directly coupled to the capacity of the storage system, what makes larger systems expensive. The PCMflux concept is developed in order to realize both a controllable and a possibly more cost effectivelatent heat storage system. These aims are addressed by separat...

  11. 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

    In this study, a typical office room with a radiant heating system and a mechanical ventilation system was selected as the research subject. Indoor temperature formulas for calculating the room heat loss (including transmission heat loss and ventilation heat loss) and heating capacity of the hybrid...... for calculating ventilation heat loss and heating capacity of radiant heating systems combined with mechanical ventilation systems. (C) 2015 Elsevier B.V. All rights reserved....... 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...

  12. 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.

  13. 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.

  14. Maximum Power Point Characteristics of Generalized Heat Engines with Finite Time and Finite Heat Capacities

    Directory of Open Access Journals (Sweden)

    Abhishek Khanna

    2012-01-01

    Full Text Available We revisit the problem of optimal power extraction in four-step cycles (two adiabatic and two heat-transfer branches when the finite-rate heat transfer obeys a linear law and the heat reservoirs have finite heat capacities. The heat-transfer branch follows a polytropic process in which the heat capacity of the working fluid stays constant. For the case of ideal gas as working fluid and a given switching time, it is shown that maximum work is obtained at Curzon-Ahlborn efficiency. Our expressions clearly show the dependence on the relative magnitudes of heat capacities of the fluid and the reservoirs. Many previous formulae, including infinite reservoirs, infinite-time cycles, and Carnot-like and non-Carnot-like cycles, are recovered as special cases of our model.

  15. Negative heat capacities in central Xe+Sn reactions

    Energy Technology Data Exchange (ETDEWEB)

    Le Neindre, N.; Bougault, R.; Gulminelli, F. [Laboratoire de Physique Corpusculaire, IN2P3-CNRS, ISMRA et Universite, 14 - Caen (France)] [and others

    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. 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......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...

  17. 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.

  18. High Capacity, Superior Cyclic Performances in All-Solid-State Lithium-Ion Batteries Based on 78Li2S-22P2S5 Glass-Ceramic Electrolytes Prepared via Simple Heat Treatment.

    Science.gov (United States)

    Zhang, Yibo; Chen, Rujun; Liu, Ting; Shen, Yang; Lin, Yuanhua; Nan, Ce-Wen

    2017-08-30

    Highly Li-ion conductive 78Li2S-22P2S5 glass-ceramic electrolytes were prepared by simple heat treatment of the glass phase obtained via mechanical ball milling. A high ionic conductivity of ∼1.78 × 10(-3) S cm(-1) is achieved at room temperature and is attributed to the formation of a crystalline phase of high lithium-ion conduction. All-solid-state lithium-ion batteries based on these glass-ceramic electrolytes are assembled by using Li2S nanoparticles or low-cost commercially available FeS2 as active cathode materials and Li-In alloys as anode. A high discharge capacity of 535 mAh g(-1) is achieved after at least 50 cycles for the all-solid-state cells with Li2S as cathode materials, suggesting a rather high capacity retention of 97.4%. Even for the cells using low-cost FeS2 as cathode materials, same high discharge capacity of 560 mAh g(-1) is also achieved after at least 50 cycles. Moreover, the Coulombic efficiency remain at ∼99% for these all-solid-state cells during the charge-discharge cycles.

  19. 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)

  20. Calculation of heat capacities of light and heavy water by path-integral molecular dynamics.

    Science.gov (United States)

    Shiga, Motoyuki; Shinoda, Wataru

    2005-10-01

    As an application of atomistic simulation methods to heat capacities, path-integral molecular dynamics has been used to calculate the constant-volume heat capacities of light and heavy water in the gas, liquid, and solid phases. While the classical simulation based on conventional molecular dynamics has estimated the heat capacities too high, the quantum simulation based on path-integral molecular dynamics has given reasonable results based on the simple point-charge/flexible potential model. The calculated heat capacities (divided by the Boltzmann constant) in the quantum simulation are 3.1 in the vapor H2O at 300 K, 6.9 in the liquid H2O at 300 K, and 4.1 in the ice Ih H2O at 250 K, respectively, which are comparable to the experimental data of 3.04, 8.9, and 4.1, respectively. The quantum simulation also reproduces the isotope effect. The heat capacity in the liquid D2O has been calculated to be 10% higher than that of H2O, while it is 13% higher in the experiment. The results demonstrate that the path-integral simulation is a promising approach to quantitatively evaluate the heat capacities for molecular systems, taking account of quantum-mechanical vibrations as well as strongly anharmonic motions.

  1. Decoding heat capacity features from the energy landscape

    Science.gov (United States)

    Wales, David J.

    2017-03-01

    A general scheme is derived to connect transitions in configuration space with features in the heat capacity. A formulation in terms of occupation probabilities for local minima that define the potential energy landscape provides a quantitative description of how contributions arise from competition between different states. The theory does not rely on a structural interpretation for the local minima, so it is equally applicable to molecular energy landscapes and the landscapes defined by abstract functions. Applications are presented for low-temperature solid-solid transitions in atomic clusters, which involve just a few local minima with different morphologies, and for cluster melting, which is driven by the landscape entropy associated with the more numerous high-energy minima. Analyzing these features in terms of the balance between states with increasing and decreasing occupation probabilities provides a direct interpretation of the underlying transitions. This approach enables us to identify a qualitatively different transition that is caused by a single local minimum associated with an exceptionally large catchment volume in configuration space for a machine learning landscape.

  2. High capacity immobilized amine sorbents

    Science.gov (United States)

    Gray, McMahan L.; Champagne, Kenneth J.; Soong, Yee; Filburn, Thomas

    2007-10-30

    A method is provided for making low-cost CO.sub.2 sorbents that can be used in large-scale gas-solid processes. The improved method entails treating an amine to increase the number of secondary amine groups and impregnating the amine in a porous solid support. The method increases the CO.sub.2 capture capacity and decreases the cost of utilizing an amine-enriched solid sorbent in CO.sub.2 capture systems.

  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)

    C. Withers, J. Cummings, B. Nigusse, E. Martin

    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. Influence of collector heat capacity and internal conditions of heat exchanger on cool-down process of small gas liquefier

    Science.gov (United States)

    Saberimoghaddam, Ali; Bahri Rasht Abadi, Mohammad Mahdi

    2018-01-01

    Joule-Thomson cooling systems are commonly used in gas liquefaction. In small gas liquefiers, transient cool-down time is high. Selecting suitable conditions for cooling down process leads to decrease in time and cost. In the present work, transient thermal behavior of Joule-Thomson cooling system including counter current helically coiled tube in tube heat exchanger, expansion valve, and collector was studied using experimental tests and simulations. The experiments were performed using small gas liquefier and nitrogen gas as working fluid. The heat exchanger was thermally studied by experimental data obtained from a small gas liquefier. In addition, the simulations were performed using experimental data as variable boundary conditions. A comparison was done between presented and conventional methods. The effect of collector heat capacity and convection heat transfer coefficient inside the tubes on system performance was studied using temperature profiles along the heat exchanger.

  5. An automated flow calorimeter for heat capacity and enthalpy measurements

    Energy Technology Data Exchange (ETDEWEB)

    Sandarusi, J.A.; Yesavage, V.F.

    1988-11-01

    An automated flow calorimeter has been developed for the measurement of heat capacity and latent enthalpies of fluids at elevated temperatures (300-700 K) and pressure (< 30 MPa) with a design accuracy of 0.1%. The method of measurement is the traditional electrical power input flow calorimeter, utilizing a precision metering pump, which eliminates the need for flow-rate monitoring. The calorimeter cell uses a unique concentric coil design with passive metal radiation shields and active guard heaters to minimize heat leakage, eliminate the traditional constant-temperature bath, and facilitate easy component replacement. An additional feature of the instrument is a complete automation system, greatly simplifying operation of the apparatus. A novel multitasking software scheme allows a single microcomputer simultaneously to control all system temperatures, provide continuous monitoring and updates on system status, and log data. Preliminary results for liquid water mean heat capacities show the equipment to be performing satisfactorily, with data accuracies of better than /plus minus/0.3%. Minor equipment modifications and better thermometry are required to reduce systemic errors and to achieve the designed operational range.

  6. 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.

    1989-01-01

    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.

  7. Anomalous dependence of the heat capacity of supercooled water on pressure and temperature

    Directory of Open Access Journals (Sweden)

    I.A. Stepanov

    2014-01-01

    Full Text Available In some papers, dependences of the isobaric heat capacity of water versus pressure and temperature were obtained. It is shown that these dependences contradict both the dependence of heat capacity on temperature for supercooled water, and an important thermodynamic equation for the dependence of heat capacity on pressure. A possible explanation for this contradiction is proposed.

  8. Heat Capacity Uncertainty Calculation for the Eutectic Mixture of Biphenyl/Diphenyl Ether Used as Heat Transfer Fluid: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Gomez, J. C.; Glatzmaier, G. C.; Mehos, M.

    2012-09-01

    The main objective of this study was to calculate the uncertainty at 95% confidence for the experimental values of heat capacity of the eutectic mixture of biphenyl/diphenyl ether (Therminol VP-1) determined from 300 to 370 degrees C. Twenty-five samples were evaluated using differential scanning calorimetry (DSC) to obtain the sample heat flow as a function of temperature. The ASTM E-1269-05 standard was used to determine the heat capacity using DSC evaluations. High-pressure crucibles were employed to contain the sample in the liquid state without vaporizing. Sample handling has a significant impact on the random uncertainty. It was determined that the fluid is difficult to handle, and a high variability of the data was produced. The heat capacity of Therminol VP-1 between 300 and 370 degrees C was measured to be equal to 0.0025T+0.8672 with an uncertainty of +/- 0.074 J/g.K (3.09%) at 95% confidence with T (temperature) in Kelvin.

  9. High temperature active heat exchanger research for latent heat storage

    Science.gov (United States)

    Alario, J.; Haslett, R.

    1982-02-01

    An active heat exchange method in a latent heat (salt) thermal energy storage system that prevents a low conductivity solid salt layer from forming on heat transfer surfaces was developed. An evaluation of suitable media with melting points in the temperature range of interest (250 to 400 C) limited the candidates to molten salts from the chloride, hydroxide and nitrate families, based on high storage capacity, good corrosion characteristics and availability in large quantities at reasonable cost. The specific salt recommended for laboratory tests was a choride eutectic (20.5KCL o 24.5NaCL o 55.MgCl2% by wt.), with a nominal melting point of 385 C. Various active heat exchange concepts were given a technical and economic comparison to a passive tube shell design for a reference application (300 MW sub t for 6 hours). Test hardware was then built for the most promising concept: a direct contact heat exchanger in which molten salt droplets are injected into a cooler counter flowing stream of liquid metal carrier fluid (lead/Bismuth).

  10. 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.

  11. APS high heat load monochromator

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Cold drink ingestion improves exercise endurance capacity in the heat.

    Science.gov (United States)

    Lee, Jason K W; Shirreffs, Susan M; Maughan, Ronald J

    2008-09-01

    To investigate the effect of drink temperature on cycling capacity in the heat. On two separate trials, eight males cycled at 66 +/- 2% VO2peak (mean +/- SD) to exhaustion in hot (35.0 +/- 0.2 degrees C) and humid (60 +/- 1%) environments. Participants ingested three 300-mL aliquots of either a cold (4 degrees C) or a warm (37 degrees C) drink during 30 min of seated rest before exercise and 100 mL of the same drink every 10 min during exercise. Rectal and skin temperatures, heart rate, and sweat rate were recorded. Ratings of thermal sensation and perceived exertion were assessed. Exercise time was longer (P drink (63.8 +/- 4.3 min) than with the warm drink (52.0 +/- 4.1 min). Rectal temperature fell by 0.5 +/- 0.1 degrees C (P drinks. There was no effect of drink temperature on mean skin temperature at rest (P = 0.870), but mean skin temperature was lower from 20 min during exercise with ingestion of the cold drink than with the warm drink (P drink than with the warm drink (P Drink temperature influenced sweat rate (1.22 +/- 0.34 and 1.40 +/- 0.41 L x h(-1) for the cold and the warm drink, respectively; P drink was ingested. Compared with a drink at 37 degrees C, the ingestion of a cold drink before and during exercise in the heat reduced physiological strain (reduced heat accumulation) during exercise, leading to an improved endurance capacity (23 +/- 6%).

  13. High Temperature Heat Exchanger Project

    Energy Technology Data Exchange (ETDEWEB)

    Anthony E. Hechanova, Ph.D.

    2008-09-30

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

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

    DEFF Research Database (Denmark)

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

    2007-01-01

    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...... potential. However, because heat gains and night ventilation periods do not coincide in time, a sufficient amount of thermal mass is needed in the building to store the heat. Assuming a 24 h-period harmonic oscillation of the indoor air temperature within a range of thermal comfort, the analytical solution...

  15. 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

  16. Comparative analysis of single- and continuously variable-capacity heat pump concepts

    Energy Technology Data Exchange (ETDEWEB)

    Rice, C.K.; Fischer, S.K.

    1984-01-01

    This work is an initial assessment of the potential benefits of continuous-capacity-modulation in electric-driven, air-to-air heat pumps for residential application. The purpose of the project was to provide a quantitative estimate of the possible annual performance gains of advanced continuously modulating heat pumps relative to single-speed designs at comparable levels of development. Previous analytical design work in this area at ORNL dealt with single-design-point, heating-mode optimization of single-speed heat pumps. For that work the ORNL Steady State Heat Pump Design Model was connected to a constrained numerical optimization code. The present work represents an extension of the earlier work in two directions. First, seasonal (heating and cooling) and annual performance factor (APF) analysis capability was added to allow direct evaluation of annual energy use from heat pump performance data generated by the ORNL heat pump model. Secondly, a modulating version of the heat pump model was developed to provide a means for simulating the steady state performance of continuously variable-speed (CVS) systems. With these tools, the APFs of both single- and continuously variable-capacity (CVC) concepts could be studied as basic heat pump design variables were varied. Based on this initial evaluation of CVS systems and considering the potential for electronics costs to further decrease as electricity prices rise, we see such advanced CVS systems as a strong future competitor to single-speed systems and as decidedly superior in energy conservation potential. To achieve this position, it seems especially important that such systems be computer optimized to take full advantage of the increased design flexibility available. Further, development of PM-ECMs or equivalent technology must continue to the point of providing speed controllers of: moderate to low cost, moderate to high performance, and high reliability. 16 refs., 12 figs.

  17. High performance flexible heat pipes

    Science.gov (United States)

    Shaubach, R. M.; Gernert, N. J.

    1985-01-01

    A Phase I SBIR NASA program for developing and demonstrating high-performance flexible heat pipes for use in the thermal management of spacecraft is examined. The program combines several technologies such as flexible screen arteries and high-performance circumferential distribution wicks within an envelope which is flexible in the adiabatic heat transport zone. The first six months of work during which the Phase I contract goal were met, are described. Consideration is given to the heat-pipe performance requirements. A preliminary evaluation shows that the power requirement for Phase II of the program is 30.5 kilowatt meters at an operating temperature from 0 to 100 C.

  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. Study of heating capacity of focused IR light soldering systems.

    Science.gov (United States)

    Anguiano, C; Félix, M; Medel, A; Bravo, M; Salazar, D; Márquez, H

    2013-10-07

    An experimental study about four optical setups used for developing a Focused IR Light Soldering System (FILSS) for Surface Mount Technology (SMT) lead-free electronic devices specifically for Ball Grid Arrays (BGA) is presented. An analysis of irradiance and infrared thermography at BGA surface is presented, as well as heat transfer by radiation and conduction process from the surface of the BGA to the solder balls. The results of this work show that the heating provided by our proposed optical setups, measured at the BGA under soldering process, meets the high temperature and uniform thermal distribution requirements, which are defined by the reflow solder method for SMT devices.

  20. High capacity oil adsorption by graphene capsules.

    Science.gov (United States)

    Ning, Guoqing; Ma, Xinlong; Wang, Mengyao; Li, Yongfeng

    2017-08-31

    We report on a chemical vapor deposition synthesis of graphene capsules (GCs) in sizes of tens to thousands of nanometers and their oil adsorption performance. MgO particles with different particle sizes are used as templates to produce GCs with different sizes. At a larger GC size and higher pore volume, a higher oil capacity is obtained. The highest oil adsorption capacity achieved by the GCs is 156 gdiesel gGC(-1), which is much higher than that obtained by expanded graphite. The adsorption capacity proportionally increases as the viscosity of the fluid increases. Both the capsule structure and the viscosity of oil are relative to the adsorption capacity, showing that capillary adsorption with a limited entrance might have contributed to the high capacity oil adsorption by GCs.

  1. Experimental determination of the high temperature heat capacity of a natural xenotime-(Y) solid solution and synthetic DyPO{sub 4} and ErPO{sub 4} endmembers

    Energy Technology Data Exchange (ETDEWEB)

    Gysi, Alexander P., E-mail: agysi@mines.edu [Department of Geology and Geological Engineering, Colorado School of Mines, 1516 Illinois Street, Golden, CO 80401 (United States); Harlov, Daniel [Geoforschungszentrum Potsdam (GFZ), Telegrafenberg, D-14473 Potsdam (Germany); Filho, Deusavan Costa [Department of Geology and Geological Engineering, Colorado School of Mines, 1516 Illinois Street, Golden, CO 80401 (United States); Williams-Jones, Anthony E. [Department of Earth and Planetary Sciences, McGill University, 3450 University St., Montreal, QC H3A 2A7 (Canada)

    2016-03-20

    Highlights: • A new DSC calibration method for minerals of geological interest is described. • The heat capacity of DyPO{sub 4}, ErPO{sub 4} and xenotime-(Y) were reliably determined using DSC. • The excess heat capacity of xenotime-(Y) indicates a non-ideal solution with other HREE. - Abstract: The heat capacity of natural xenotime-(Y) and synthetic DyPO{sub 4} and ErPO{sub 4} crystals was determined by differential scanning calorimetry (DSC) at temperatures of 298.15 K to 868.15 K and a pressure of 0.1 MPa. The aim of the study was to develop a method to accurately measure the isobaric heat capacity (C{sub P}) of rare earth element (REE) phosphates, compare the results to data from adiabatic calorimetric experiments, and evaluate the deviation from ideality of the C{sub P} of the natural xenotime-(Y) solid solution. The measured C{sub P} data (in J mol{sup −1} K{sup −1}) can be described by the relationships: 185.5 − 751.9T{sup −0.5} − 3.261e + 06 T{sup −2} for DyPO{sub 4}; 207.2 − 1661T{sup −0.5} − 5.289e + 05 T{sup −2} for ErPO{sub 4}; and 208 − 1241T{sup −0.5} − 2.493e + 06 T{sup −2} for xenotime-(Y); where T is the temperature in K. The heat capacity data for natural xenotime-(Y) were used to determine the excess function for the solid solution, which yields an excess heat capacity ranging between 7.9 and 10.7%, well within the range of the DSC method used in this study. The experiments indicate that xenotime-(Y) forms a non-ideal solid solution. Future DSC studies will provide important data for developing a solid solution model for the incorporation of REE in xenotime-(Y).

  2. High specific heat superconducting composite

    Science.gov (United States)

    Steyert, Jr., William A.

    1979-01-01

    A composite superconductor formed from a high specific heat ceramic such as gadolinium oxide or gadolinium-aluminum oxide and a conventional metal conductor such as copper or aluminum which are insolubly mixed together to provide adiabatic stability in a superconducting mode of operation. The addition of a few percent of insoluble gadolinium-aluminum oxide powder or gadolinium oxide powder to copper, increases the measured specific heat of the composite by one to two orders of magnitude below the 5.degree. K. level while maintaining the high thermal and electrical conductivity of the conventional metal conductor.

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

    OpenAIRE

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

    2013-01-01

    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...

  4. A Heat Vulnerability Index: Spatial Patterns of Exposure, Sensitivity and Adaptive Capacity for Santiago de Chile

    Science.gov (United States)

    Palme, Massimo; de la Barrera, Francisco

    2016-01-01

    Climate change will worsen the high levels of urban vulnerability in Latin American cities due to specific environmental stressors. Some impacts of climate change, such as high temperatures in urban environments, have not yet been addressed through adaptation strategies, which are based on poorly supported data. These impacts remain outside the scope of urban planning. New spatially explicit approaches that identify highly vulnerable urban areas and include specific adaptation requirements are needed in current urban planning practices to cope with heat hazards. In this paper, a heat vulnerability index is proposed for Santiago, Chile. The index was created using a GIS-based spatial information system and was constructed from spatially explicit indexes for exposure, sensitivity and adaptive capacity levels derived from remote sensing data and socio-economic information assessed via principal component analysis (PCA). The objective of this study is to determine the levels of heat vulnerability at local scales by providing insights into these indexes at the intra city scale. The results reveal a spatial pattern of heat vulnerability with strong variations among individual spatial indexes. While exposure and adaptive capacities depict a clear spatial pattern, sensitivity follows a complex spatial distribution. These conditions change when examining PCA results, showing that sensitivity is more robust than exposure and adaptive capacity. These indexes can be used both for urban planning purposes and for proposing specific policies and measures that can help minimize heat hazards in highly dynamic urban areas. The proposed methodology can be applied to other Latin American cities to support policy making. PMID:27606592

  5. 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.

  6. Application of Neumann-Kopp rule for the estimation of heat capacity of mixed oxides

    Energy Technology Data Exchange (ETDEWEB)

    Leitner, J., E-mail: jindrich.leitner@vscht.cz [Department of Solid State Engineering, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague 6 (Czech Republic); Vonka, P. [Department of Physical Chemistry, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague 6 (Czech Republic); Sedmidubsky, D. [Department of Inorganic Chemistry, Institute of Chemical Technology Prague, Technicka 5, 166 28 Prague 6 (Czech Republic); European Commission, JRC, Institute for Transuranium Elements, Postbox 2340, D-76125 Karlsruhe (Germany); Svoboda, P. [Department of Condensed Matter Physics, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 5, 120 00 Prague 2 (Czech Republic)

    2010-01-10

    The empirical Neumann-Kopp rule (NKR) for the estimation of temperature dependence of heat capacity of mixed oxide is analyzed. NKR gives a reasonable estimate of C{sub pm} for most mixed oxides around room temperature, but at both low and high temperatures the accuracy of the estimate is substantially lowered. At very low temperatures, the validity of NKR is shown to be predominantly determined by the relation between the characteristic Debye and Einstein temperatures of a mixed oxide and its constituents. At high temperatures, the correlation between their molar volumes, volume expansion coefficients and compressibilities takes the dominance. In cases where the formation of a mixed oxide is not accompanied by any volume change, the difference between dilatation contributions to heat capacity of a mixed oxide and its constituents is exclusively negative. It turns out that in the high-temperature range, where the contribution of harmonic lattice vibrations approached the 3NR limit, {Delta}{sub ox}C{sub p} assumes negative values. For more complex oxides whose heat capacity has contributions from terms such as magnetic ordering, electronic excitations, the applicability of NKR is only restricted to lattice and dilatation terms.

  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. 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.

  9. High capacity optical links for datacentre connectivity

    DEFF Research Database (Denmark)

    Tafur Monroy, Idelfonso; Usuga, Mario; Vegas Olmos, Juan José

    There is a timely and growing demand for high capacity optical data transport solutions to provide connectivity inside data centres and between data centres located at different geographical locations. The requirements for reach are in the order of 2 km for intra-datacentre and up to 100 km...

  10. High temperature heat exchange: nuclear process heat applications

    Energy Technology Data Exchange (ETDEWEB)

    Vrable, D.L.

    1980-09-01

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

  11. 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 high intrinsic capacity for aerobic exercise and better health have higher body 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.

  12. Saturated-liquid heat capacity of organic compounds: new empirical correlation model

    Directory of Open Access Journals (Sweden)

    DUSAN K. GROZDANIC

    2004-03-01

    Full Text Available A new saturated-liquid heat capacity model is recommended. This model is tested and compared with the known polynomial and quasi-polynomial models on 39 sets with 1453 experimental heat capacity data. The obtained results indicate that the new model is better then the existing models, especially near the critical point.

  13. 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.

  14. 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.

  15. 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.

  16. [Executive functions and high intellectual capacity].

    Science.gov (United States)

    Sastre-Riba, S; Viana-Saenz, L

    2016-01-01

    High intellectual capacity is a process in development in which the executive functions (inhibition, working memory and flexibility) play a role in the optimal manifestation of their potential. To explore the effectiveness of executive functioning among the profiles of high capacity giftedness and (convergent or divergent) talent. The study examines 78 children with high intellectual capacity aged 8-15 years with profiles of giftedness (n = 21), convergent talent (n = 39) or divergent talent (n = 18). A series of tests were administered including the Battery of Differential and General Aptitudes or the Differential Aptitude Test (depending on the age) and the Torrance Test of Creative Thinking, as well as the Wisconsin Card Sorting Test, the Corsi Test and the Go-No Go Test by means of the Psychology Experiment Building Language platform. A multivariate analysis of variance was performed to determine the relationship between executive function and intellectual profile. Significant differences are obtained between the profiles studied and the executive functions of flexibility and inhibition, but not in working memory. Working memory is similar across the profiles studied, but the complex profile of giftedness displays better executive functioning, with greater flexibility and inhibition than talent, especially of the convergent type.

  17. High Temperature Composite Heat Exchangers

    Science.gov (United States)

    Eckel, Andrew J.; Jaskowiak, Martha H.

    2002-01-01

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

  18. Characterization of Molten CZT Using Thermal Conductivity and Heat Capacity

    Energy Technology Data Exchange (ETDEWEB)

    Nero, Franco [Y-12 National Security Complex, Oak Ridge, TN (United States); Jackson, Maxx [Y-12 National Security Complex, Oak Ridge, TN (United States); Stowe, Ashley [Y-12 National Security Complex, Oak Ridge, TN (United States)

    2017-10-10

    To compare thermal conductivity of a polycrystalline semiconductor to the single crystal semiconductor using thermo-physical data acquired from Simultaneous Thermal Analysis and Transient Plane Source heating.

  19. High Capacity Radio over Fiber Transmission Links

    DEFF Research Database (Denmark)

    Caballero Jambrina, Antonio

    confirmed that this configuration provides high linear end-to-end transmission links and is capable of transparent transport of high spectral efficient modulation formats. Furthermore, this thesis introduces a novel approach for the generation and detection of high speed wireless signals in mm-wave......This thesis expands the state-of-the-art on the detection of high speed wireless signals using optics. Signal detection at speeds over 1 Gbps at carrier Radio Frequency (RF) ranging from 5 GHz to 100 GHz have been achieved by applying novel concepts on optical digital coherent receivers....... This achievement has satisfied the requirements on transmission robustness and high capacity of next generation hybrid optical fibre-wireless networks. One important contribution of this thesis is the novel concept of photonic downconversion with free-running pulsed laser source for phase modulated Radio...

  20. 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.

  1. Heat capacities of xenotime-type ceramics: An accurate ab initio prediction

    Science.gov (United States)

    Ji, Yaqi; Beridze, George; Bosbach, Dirk; Kowalski, Piotr M.

    2017-10-01

    Because of ability to incorporate actinides into their structure, the lanthanide phosphate ceramics (LnPO4) are considered as potential matrices for the disposal of nuclear waste. Here we present highly reliable ab initio prediction of the variation of heat capacities and the standard entropies of these compounds in zircon structure along lanthanide series (Ln = Dy, …,Lu) and validate them against the existing experimental data. These data are helpful for assessment of thermodynamic parameters of these materials in the context of using them as matrices for immobilization of radionuclides for the purpose of nuclear waste management.

  2. A heat capacity anomaly of the superconducting transition in a ferromagnetic superconductor UGe{sub 2}

    Energy Technology Data Exchange (ETDEWEB)

    Tateiwa, Naoyuki; Kobayashi, Tatsuo C.; Amaya, Kiichi; Haga, Yoshinori; Settai, Rikio; Onuki, Yoshichika

    2003-05-15

    We performed the heat capacity, C(T), measurement under high pressure on a ferromagnetic superconductor UGe{sub 2}, in order to study the pressure dependence of the anomaly in C(T) associated with the superconducting transition. A clear peak appears only around a critical pressure P{sub c}* where an another transition temperature T* becomes 0 K. This result suggests that a bulk superconducting phase exists in the narrower pressure region around P{sub c}* than those clarified by previous studies.

  3. 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

    2018-01-01

    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.

  4. The NASA CSTI High Capacity Power Program

    Science.gov (United States)

    Winter, Jerry M.

    1991-01-01

    NASA's Civil Space Technology Initiative (CSTI) has as its primary goal the improvement of space nuclear power-related technologies and their interactions with the given mission environment. The CSTI High Capacity Power Program supports and advances all nonnuclear aspects of the national SP-100 Space Nuclear Reactor Program, including the demonstration of a 1050 K Stirling Space Power System capable of employing the full output capability of the SP-100 reactor. Thermoelectric technology capable of reaching Z values of 0.001/K with SiGe/GaP will be demonstrated in the course of the program.

  5. 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.

  6. 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.

  7. Moisture buffering capacity of highly absorbing materials

    Energy Technology Data Exchange (ETDEWEB)

    Cerolini, S.; D' Orazio, M.; Stazi, A. [Department of Architecture, Construction and Structures (DACS), Faculty of Engineering, Polytechnic University of Marche, Via Brecce Bianche, 60100 Ancona (Italy); Di Perna, C. [Department of Energetics, Faculty of Engineering, Polytechnic University of Marche, Via Brecce Bianche, 60100 Ancona (Italy)

    2009-02-15

    This research investigates the possibility to use highly absorbing materials to dampen indoor RH% variations. The practical MBV of sodium polyacrylate, cellulose-based material, perlite and gypsum is evaluated for a daily cyclic exposure that alternates high (75%) and low (33%) RH% levels for 8 h and 16 h, respectively. The adjustment velocity to RH% variations and the presence of hysteretic phenomena are also presented. The cellulose-based material proves to be the most suitable for moisture buffering applications. Starting from this material's properties, the effect of thickness, vapour resistance factor ({mu}) and mass surface exchange coefficient (Z{sub v}) on sorption capacity is evaluated by the use of a numerical model. (author)

  8. Magnetocaloric effect and the heat capacity of ferrimagnetic nanosystems in magnetic fluids

    Science.gov (United States)

    Korolev, V. V.; Aref'ev, I. M.; Ramazanova, A. G.

    2007-10-01

    The specific heat capacity of a magnetite-based magnetic fluid and changes in the magnetic part of the molar heat capacity of its magnetic phase in magnetic fields of 0 0.7 T were determined calorimetrically over the temperature range 288 353 K. The temperature dependence of changes in the magnetic part of entropy in an applied magnetic field was calculated. It was found that the field dependence of heat capacity had a maximum in fields of 0.3 0.4 T, and the temperature dependences of changes in the magnetic part of heat capacity Δ C p ( H) and entropy Δ S m( H) had maxima at the magnetic phase transition temperature.

  9. High specific energy, high capacity nickel-hydrogen cell design

    Science.gov (United States)

    Wheeler, James R.

    1993-01-01

    A 3.5 inch rabbit-ear-terminal nickel-hydrogen cell was designed and tested to deliver high capacity at steady discharge rates up to and including a C rate. Its specific energy yield of 60.6 wh/kg is believed to be the highest yet achieved in a slurry-process nickel-hydrogen cell, and its 10 C capacity of 113.9 AH the highest capacity yet of any type in a 3.5 inch diameter size. The cell also demonstrated a pulse capability of 180 amps for 20 seconds. Specific cell parameters and performance are described. Also covered is an episode of capacity fading due to electrode swelling and its successful recovery by means of additional activation procedures.

  10. 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)

  11. Experimental Research On Gas Injection High Temperature Heat Pump With An Economizer

    OpenAIRE

    He, Yongning; Jin, Lei; Cao, Feng; Chen, Shengkun

    2014-01-01

    Gas injection technology is often used in cold regions to solve heat pump’s low heating capacity and high discharge temperature at low ambient temperature. Injecting gas into port opened at specific position of compressor could increase mass flow rate of compressor and total heating capacity of heat pump. Gas injection also changes compression ratio of compressor and decreases discharge temperature. An optimal gas injection pressure is got when the coefficient of performance reached to peak v...

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

    Science.gov (United States)

    Sedlmeier, Felix; Netz, Roland R

    2013-03-21

    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 ΔC(p) 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.

  13. High-Capacity Communications from Martian Distances

    Science.gov (United States)

    Williams, W. Dan; Collins, Michael; Hodges, Richard; Orr, Richard S.; Sands, O. Scott; Schuchman, Leonard; Vyas, Hemali

    2007-01-01

    High capacity communications from Martian distances, required for the envisioned human exploration and desirable for data-intensive science missions, is challenging. NASA s Deep Space Network currently requires large antennas to close RF telemetry links operating at kilobit-per-second data rates. To accommodate higher rate communications, NASA is considering means to achieve greater effective aperture at its ground stations. This report, focusing on the return link from Mars to Earth, demonstrates that without excessive research and development expenditure, operational Mars-to-Earth RF communications systems can achieve data rates up to 1 Gbps by 2020 using technology that today is at technology readiness level (TRL) 4-5. Advanced technology to achieve the needed increase in spacecraft power and transmit aperture is feasible at an only moderate increase in spacecraft mass and technology risk. In addition, both power-efficient, near-capacity coding and modulation and greater aperture from the DSN array will be required. In accord with these results and conclusions, investment in the following technologies is recommended:(1) lightweight (1 kg/sq m density) spacecraft antenna systems; (2) a Ka-band receive ground array consisting of relatively small (10-15 m) antennas; (3) coding and modulation technology that reduces spacecraft power by at least 3 dB; and (4) efficient generation of kilowatt-level spacecraft RF power.

  14. An automated flow calorimeter for heat capacity and enthalpy measurements at elevated temperatures and pressures

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.

    1990-08-31

    The need for highly accurate thermal property data for a broad range of new application fluids is well documented. To facilitate expansion of the current thermophysical database, an automated flow calorimeter was developed for the measurement of highly accurate isobaric heat capacities and enthalpies of fluids at elevated temperatures and pressures. The experimental technique utilizes traditional electrical power input, adiabatic flow calorimetry with a precision metering pump that eliminates the need for on-line flow rate monitoring. In addition, a complete automation system, greatly simplifies the operation of the apparatus and increases the rapidity of the measurement process. The range over which the instrument was tested, was 300--600 K and 0--12 Mpa, although the calorimeter should perform up to the original design goals of 700 K and 30 MPa. The new flow calorimeter was evaluated by measuring the mean, isobaric, specific heat capacities of liquid water and n-pentane. These experiments yielded an average deviation from the standard literature data of +0.02% and a total variation of 0.05%. Additional data analysis indicated that the overall measurement uncertainty was conservatively estimated as 0.2% with an anticipated precision of 0.1--0.15% at all operating conditions. 44 refs., 27 figs., 2 tabs.

  15. Ambient heat capacities and entropies of ionic solids: a unique view using the Debye equation.

    Science.gov (United States)

    Glasser, Leslie

    2013-06-03

    Entropies of solids are obtained experimentally as integrals of measured heat capacities over the temperature range from zero to ambient. Correspondingly, the Debye phonon distribution equation for solids provides a theoretical connection between these two chemical thermodynamic measures. We examine how the widely applicable Debye equation illuminates the relation between the corresponding experimental measures using more than 250 ionic solids. Estimation of heat capacities for simple ionic solids by the Dulong-Petit heat capacity limit, by the Neumann-Kopp elemental sum, and by the ion sum method is examined in relation to the Debye equation. We note that, and explain why, the ambient temperature heat capacities and entropies of ionic solids are found to be approximately equal, and how deviations from equality may be related to the Debye temperature, ΘD, which characterizes the Debye equation. It is also demonstrated that Debye temperatures may be readily estimated from the experimental ratio of ambient heat capacity to entropy, C(p)/S(p), rather than requiring resort to elaborate theoretical or experimental procedures for their determination. Correspondingly, ambient mineral entropies and heat capacities are linearly correlated and may thus be readily estimated from one another.

  16. High Temperature Thermoacoustic Heat Pump

    Energy Technology Data Exchange (ETDEWEB)

    Tijani, H.; Spoelstra, S. [ECN Biomass and Energy Efficiency, Petten (Netherlands)

    2012-07-15

    Thermoacoustic technology can provide new types of heat pumps that can be deployed in different applications. Thermoacoustic heat pumps can for example be applied in dwellings to generate cooling or heating. Typically, space and water heating makes up about 60% of domestic and office energy consumption. The application of heat pumps can contribute to achieve energy savings and environmental benefits by reducing CO2 and NOx emissions. This paper presents the study of a laboratory scale thermoacoustic-Stirling heat pump operating between 10C and 80C which can be applied in domestics and offices. The heat pump is driven by a thermoacoustic-Stirling engine. The experimental results show that the heat pump pumps 250 W of heat at 60C at a drive ratio of 3.6 % and 200 W at 80C at a drive ratio of 3.5 %. The performance for both cases is about 40% of the Carnot performance. The design, construction, and performance measurements of the heat pump will be presented and discussed.

  17. Effect of Inhomogeneous Heat Flow on the Enhancement of Heat Capacity in Helium-II by Counterflow near Tλ

    Science.gov (United States)

    Boyd, S. T. P.; Chatto, A. R.; Lee, R. A. M.; Duncan, R. V.; Goodstein, D. L.

    2006-09-01

    In 2000 Harter et al. reported the first measurements of the enhancement of the heat capacity ΔCQ≡C(Q)-C(Q=0) of helium-II transporting a heat flux density Q near Tλ. Surprisingly, their measured ΔCQ was ˜7-12 times larger than predicted, depending on which theory was assumed. In this report we present a candidate explanation for this discrepancy: unintended heat flux inhomogeneity. Because C(Q) should diverge at a critical heat flux density Qc, homogeneous heat flow is required for an accurate measurement. We present results from numerical analysis of the heat flow in the Harter et al. cell indicating that substantial inhomogeneity occurred. We determine the effect of the inhomogeneity on ΔCQ and find rough agreement with the observed disparity between prediction and measurement.

  18. 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.

  19. High Capacity Battery Cell Flight Qualified

    Science.gov (United States)

    McKissock, Barbara I.

    1997-01-01

    The High Capacity Battery Cell project is an effort equally funded by the NASA Lewis Research Center and Hughes Space and Communications Company (a unit of Hughes Aircraft Company) to develop and flight qualify a higher capacity nickel hydrogen battery for continuing use on commercial spacecraft. The larger diameter, individual pressure vessel cell will provide approximately twice the power, while occupying the same volume, as the current state-of-the-art nickel hydrogen cell. These cells are also anticipated to reduce battery cost by 20 percent. The battery is currently booked for use on 26 spacecraft, with the first flight scheduled in 1997. A strong requirement for batteries with higher power levels (6 to 12 kW), long life, and reduced cost was identified in studies of the needs of commercial communications spacecraft. With the design developed in this effort, the higher power level was accommodated without having to modify the rest of the existing spacecraft bus. This design scaled-up the existing state-of-the-art nickel hydrogen battery cell from a 3.5-in., 50-Ahr cell to a 5.5-in., 350-Ahr cell. An improvement in cycle life was also achieved by the use of the 26-percent KOH electrolyte design developed by NASA Lewis. The cell design was completed, and flight batteries were built and flight qualified by Hughes Space and Communications Company with input from NASA Lewis. Two batteries were shipped in September 1996 to undergo life cycle testing under the purview of NASA Lewis.

  20. 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.

  1. Building the UPPA high capacity tensiometer

    Directory of Open Access Journals (Sweden)

    Mendes Joao

    2016-01-01

    Full Text Available High capacity tensiometers (HCTs are sensors capable of directly measuring tensile pore water pressure (suction in soils. HCTs are typically composed of a casing that encapsulates a high air entry value ceramic filter, a water reservoir and a pressure sensing element. Since the creation of the first HCT by Ridley and Burland in 1993 at Imperial College London, HCTs have been almost exclusively built and used in academic research. The limited use in industrial applications can be explained by a lack of unsaturated soil mechanics knowledge among engineering practitioners but also by the technical difficulties associated to the direct measurement of tensile water pressures beyond the cavitation limit of -100kPa. In this paper, we present the recent design and manufacture of a new HCT at the Université de Pau et des Pays de l’Adour (UPPA in France. Different prototypes were tried by changing the main components of the device including the type of ceramic filter, pressure transducer and geometry of the external casing. In particular, two ceramic filters of distinct porosity, three pressure transducers with distinct materials/geometries and four casing designs were tested.

  2. The NASA CSTI high capacity power project

    Science.gov (United States)

    Winter, J.; Dudenhoefer, J.; Juhasz, A.; Schwarze, G.; Patterson, R.; Ferguson, D.; Titran, R.; Schmitz, P.; Vandersande, J.

    1992-01-01

    The SP-100 Space Nuclear Power Program was established in 1983 by DOD, DOE, and NASA as a joint program to develop technology for military and civil applications. Starting in 1986, NASA has funded a technology program to maintain the momentum of promising aerospace technology advancement 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 a wide range of future space applications. The elements of the Civilian Space Technology Initiative (CSTI) High Capacity Power Project include Systems Analysis, Stirling Power Conversion, Thermoelectric Power Conversion, Thermal Management, Power Management, Systems Diagnostics, Environmental Interactions, and Material/Structural Development. Technology advancement in all elements is required to provide the growth capability, high reliability and 7 to 10 year lifetime demanded for future space nuclear power systems. The overall project will develop and demonstrate the technology base required to provide a wide range of modular power systems compatible with the SP-100 reactor which facilitates operation during lunar and planetary day/night cycles as well as allowing spacecraft operation at any attitude or distance from the sun. Significant accomplishments in all of the project elements will be presented, along with revised goals and project timelines recently developed.

  3. A New Method for the Determination of the Specific Heat Capacity Using Laser-Flash Calorimetry Down to 77K

    Science.gov (United States)

    Göbel, A.; Hemberger, F.; Vidi, S.; Ebert, H.-P.

    2013-05-01

    A new method for evaluation of the specific heat capacity in the temperature regime between 77K and 330K using laser-flash calorimetry is presented. Usually, laser-flash calorimetry is accomplished by performing an additional laser-flash measurement on a reference specimen with a known specific heat capacity and by comparing the maximum rear-side temperatures rises. In this study, the calibration is achieved by comparison of the rear-side temperature rise to specific-heat-capacity data determined by other methods in an adjacent temperature regime. Subsequently, the thus yielded proportional factor is used for the evaluation of the specific heat capacity from laser-flash measurements at temperatures where no specific-heat-capacity data are available. The reliability of this method is shown by performing measurements on a material with known specific heat capacity, aluminum oxide. Furthermore, the specific heat capacity and thermal conductivity of borosilicate crown glass (BK7) was determined experimentally.

  4. 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...... properties with a fine resolution, down to 1 millimeter. Special attention needs to be taken when determining the specific heat capacity in the comparative method. First of all, the test and reference sample should be of nearly identical thickness. Secondly, their heat diffusion time should be comparable, so...... 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....

  5. 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.

  6. Towards green high capacity optical networks

    Science.gov (United States)

    Glesk, I.; Mohd Warip, M. N.; Idris, S. K.; Osadola, T. B.; Andonovic, I.

    2012-02-01

    The demand for fast, secure, energy efficient high capacity networks is growing. It is fuelled by transmission bandwidth needs which will support among other things the rapid penetration of multimedia applications empowering smart consumer electronics and E-businesses. All the above trigger unparallel needs for networking solutions which must offer not only high-speed low-cost "on demand" mobile connectivity but should be ecologically friendly and have low carbon footprint. The first answer to address the bandwidth needs was deployment of fibre optic technologies into transport networks. After this it became quickly obvious that the inferior electronic bandwidth (if compared to optical fiber) will further keep its upper hand on maximum implementable serial data rates. A new solution was found by introducing parallelism into data transport in the form of Wavelength Division Multiplexing (WDM) which has helped dramatically to improve aggregate throughput of optical networks. However with these advancements a new bottleneck has emerged at fibre endpoints where data routers must process the incoming and outgoing traffic. Here, even with the massive and power hungry electronic parallelism routers today (still relying upon bandwidth limiting electronics) do not offer needed processing speeds networks demands. In this paper we will discuss some novel unconventional approaches to address network scalability leading to energy savings via advance optical signal processing. We will also investigate energy savings based on advanced network management through nodes hibernation proposed for Optical IP networks. The hibernation reduces the network overall power consumption by forming virtual network reconfigurations through selective nodes groupings and by links segmentations and partitionings.

  7. Heat Capacity, Crystallization, and Nucleation in Poly(vinyl alcohol) Thin Films

    Science.gov (United States)

    Thomas, David; Wurm, Andreas; Zhuravlev, Evgeny; Schick, Christoph; Cebe, Peggy

    Polyvinyl alcohol (PVA) is hydrophilic, biodegradable, semi-crystalline polymer with a wide array of applications ranging from textiles and packaging to medicine. Despite possessing favorable properties, PVA thermally degrades at temperatures just in excess of 200 °C which occurs slightly below the observed peak endothermic melting peak at 203 °C. Utilizing fast scanning calorimetry it is possible to minimize sample degradation allowing measurements of the liquid phase heat capacity as well as study nucleation and crystallization from the amorphous melt state. Samples cut from parent films 2-3 μm thick were placed on UFSC1 sensors and brought between -80 and 270 °C at rates of 2000 °C/s under a nitrogen atmosphere. After five complete cycles samples did not show any signs of degradation. By fitting the symmetry corrected glassy phase heat capacity with literature values for the specific heat capacity from the ATHAS databank sample masses were determined to vary between 15-50 ng. Homogeneous nucleation was observed for all samples cooled from the melt with peak temperature 123 °C. Fitting linear heat capacity baselines in the melt and glassy states it was possible to obtain an experimental measurement of the heat capacity increment 44.5 J/mol K at the glass transition 85 °C. NSF DMR-1206010.

  8. A Framework for Spatial Assessment of Local Level Vulnerability and Adaptive Capacity to Extreme Heat

    Science.gov (United States)

    Wilhelmi, O.; Hayden, M.; Harlan, S.; Ruddell, D.; Komatsu, K.; England, B.; Uejio, C.

    2008-12-01

    Changing climate is predicted to increase the intensity and impacts of heat waves prompting the need to develop preparedness and adaptation strategies that reduce societal vulnerability. Central to understanding societal vulnerability, is adaptive capacity, the potential of a system or population to modify its features/behaviors so as to better cope with existing and anticipated stresses and fluctuations. Adaptive capacity influences adaptation, the actual adjustments made to cope with the impacts from current and future hazardous heat events. Understanding societal risks, vulnerabilities and adaptive capacity to extreme heat events and climate change requires an interdisciplinary approach that includes information about weather and climate, the natural and built environment, social processes and characteristics, interactions with the stakeholders, and an assessment of community vulnerability. This project presents a framework for an interdisciplinary approach and a case study that explore linkages between quantitative and qualitative data for a more comprehensive understanding of local level vulnerability and adaptive capacity to extreme heat events in Phoenix, Arizona. In this talk, we will present a methodological framework for conducting collaborative research on societal vulnerability and adaptive capacity on a local level that includes integration of household surveys into a quantitative spatial assessment of societal vulnerability. We highlight a collaborative partnership among researchers, community leaders and public health officials. Linkages between assessment of local adaptive capacity and development of regional climate change adaptation strategies will be discussed.

  9. Heat capacities and asymmetric criticality of coexistence curves for benzonitrile + alkanes and dimethyl carbonate + alkanes.

    Science.gov (United States)

    Huang, Meijun; Lei, Yuntao; Yin, Tianxiang; Chen, Zhiyun; An, Xueqin; Shen, Weiguo

    2011-11-24

    The critical behavior of isobaric heat capacities per unit volume for a series of critical binary solutions {benzonitrile + octane, or dodecane, or hexadecane} and {dimethyl carbonate + nonane, or decane, or dodecane} were studied. The corresponding exponent was obtained to be in consistent with the 3D-Ising value. The amplitudes in one-phase and two-phase regions were deduced, which were used to test some critical amplitude ratios. Analysis of the dependence of the effective critical exponent of the heat capacity on the temperature indicated a critical crossover from the 3D-Ising to the mean-field for all the studied systems. It was found that the heat capacity does play an important role for describing the asymmetric criticality of coexistence curves by the complete scaling theory. © 2011 American Chemical Society

  10. Excess enthalpy, density, and heat capacity for binary systems of alkylimidazolium-based ionic liquids + water

    Energy Technology Data Exchange (ETDEWEB)

    Garcia-Miaja, Gonzalo; Troncoso, Jacobo [Departamento de Fisica Aplicada, Universidad de Vigo, Facultad de Ciencias, Campus As Lagoas, 32004 Ourense (Spain); Romani, Luis [Departamento de Fisica Aplicada, Universidad de Vigo, Facultad de Ciencias, Campus As Lagoas, 32004 Ourense (Spain)], E-mail: romani@uvigo.es

    2009-02-15

    Experimental measurements of excess molar enthalpy, density, and isobaric molar heat capacity are presented for a set of binary systems ionic liquid + water as a function of temperature at atmospheric pressure. The studied ionic liquids are 1-butyl-3-methylpyridinium tetrafluoroborate, 1-ethyl-3-methylimidazolium ethylsulfate, 1-butyl-3-methylimidazolium methylsulfate, 1-butyl-3-methylimidazolium trifluoromethanesulfonate, and 1-ethyl-3-methylimidazolium trifluoromethanesulfonate. Excess molar enthalpy was measured at 303.15 K whereas density and heat capacity were determined within the temperature range (293.15 to 318.15) K. From experimental data, excess molar volume and excess molar isobaric heat capacity were calculated. The analysis of the excess properties reveals important differences between the studied ionic liquids which can be ascribed to their capability to form hydrogen bonds with water molecules.

  11. THERMAL STUDY OF THE DIII-D MACHINE HEAT REMOVAL CAPACITY

    Energy Technology Data Exchange (ETDEWEB)

    YIP,H; ADERSON,P.M; HOLTROP,K.L; HARRISON,S

    2003-10-01

    OAK-B135 With each plasma shot, the DIII-D tokamak dissipates 0.5 to 1.0 GJ of energy. Plasma shots may occur as frequently as every ten minutes, and the energy is removed in the form of heat by a cooling water system. to remove heat from the machine, cooling water circulates through each major heat source. These sources include the power supplies, motor/generator, rf current drives, neutral beam power supplies, magnetic field coils, and vacuum vessel. The cooling water system consists of isolated primary and secondary cooling loops separated by intermediate heat exchangers. As future DIII-D plans include operation during summer months and longer pulse duration, the cooling system's overall heat removal capability and performance efficiency must be assessed. Temperature and flow data from around the DIII-D facility are collected by a programmable logic controller (PLC); the data are used to analyze the heat generating sources, the heat transfer rate to intermediate heat exchangers, and the ultimate heat rejection to the environment via the cooling towers. A comparison of the original DIII-D machine design versus the actual performance determines the margin of heat removal capacity. projections of the heat removal rate for various longer plasma shots are made. Improvements in design and/or operational procedure will be necessary to attain the desired pulse duration.

  12. Cryogenic Heat Load and Refrigeration Capacity Management at the Large Hadron Collider (LHC)

    CERN Document Server

    Claudet, S; Serio, L; Tavian, L; Van Weelderen, R; Wagner, U

    2009-01-01

    The Large Hadron Collider (LHC) is a 26.7 km high-energy proton and ion collider based on several thousand high-field superconducting magnets operating in superfluid helium below 2 K, now under commissioning at CERN. After a decade of development of the key technologies, the project was approved for construction in 1994 and the industrial procurement for the cryogenic system launched in 1997, concurrently with the completion of the R&D program. This imposed to base the sizing of the refrigeration plants on estimated and partially measured values of static and dynamic heat loads, with adequate uncertainty and overcapacity coefficients to cope with unknowns in machine configuration and in physical processes at work. With the cryogenic commissioning of the complete machine, full-scale static heat loads could be measured, thus confirming the correctness of the estimates and the validity of the approach, and safeguarding excess refrigeration capacity for absorbing the beam-induced dynamic loads. The metho...

  13. 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. 

  14. Investigations of temperature dependences of electrical resistivity and specific heat capacity of metals

    Energy Technology Data Exchange (ETDEWEB)

    Eser, Erhan, E-mail: eserphy@gmail.com [Department of Physics, Polatlı Faculty of Arts and Sciences, Gazi University, Polatlı, Ankara (Turkey); Koç, Hüseyin [Department of Electrical and Electronics Engineering, Faculty of Engineering, Muş Alparslan University, Muş (Turkey)

    2016-07-01

    In this study, we calculated the electrical resistivity and heat capacities of some ideal metals (Cu, Pt, and Pd) using a method that it employs the statistical model and Debye functions. The method is used to provide a simple and reliable analytical procedure for wide temperature range. The results obtained for the electrical resistivity and heat capacity have been compared with the results in literature. The results obtained at low temperature are in excellent agreement with experimental and theoretical results. Finally the used approximation and analytical method are a useful approach to calculate thermophysical properties of metals.

  15. 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

  16. 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.

  17. Molecular mobility, thermodynamics and stability of griseofulvin's ultraviscous and glassy states from dynamic heat capacity.

    Science.gov (United States)

    Tombari, E; Presto, S; Johari, G P; Shanker, Ravi M

    2008-04-01

    To determine the calorimetric relaxation time needed for modeling griseofulvin's stability against crystallization during storage. Both temperature-modulated and unmodulated scanning calorimetry have been used to determine the heat capacity of griseofulvin in the glassy and melt state. The calorimetric relaxation time, tau cal, of its melt varies with the temperature T according to the relation, tau cal [s] = 10(-13.3) exp [2, 292 /(T[K] - 289.5)] , and the distribution of relaxation times parameter is 0.67. The unrelaxed heat capacity of the griseofulvin melt is equal to its vibrational heat capacity. Griseofulvin neither crystallizes on heating to 373 K at 1 K/h rate, nor on cooling. Molecular mobility and vibrational heat capacity measured here are more reliable for modeling a pharmaceutical's stability against crystallization than the currently used kinetics-thermodynamics relations, and molecular mobility in the (fixed structure) glassy state is much greater than the usual extrapolation from the melt state yields. Molecular relaxation time of the glassy state of griseofulvin is about 2 months at 298 K, and longer at lower temperatures. It would spontaneously increase with time. If the long-range motions alone were needed for crystallization, griseofulvin would become more stable against crystallization during storage.

  18. Heat capacities and thermal diffusivities of n-alkane acid ethyl esters—biodiesel fuel components

    Science.gov (United States)

    Bogatishcheva, N. S.; Faizullin, M. Z.; Nikitin, E. D.

    2017-09-01

    The heat capacities and thermal diffusivities of ethyl esters of liquid n-alkane acids C n H2 n-1O2C2H5 with the number of carbon atoms in the parent acid n = 10, 11, 12, 14, and 16 are measured. The heat capacities are measured using a DSC 204 F1 Phoenix heat flux differential scanning calorimeter (Netzsch, Germany) in the temperature range of 305-375 K. Thermal diffusivities are measured by means of laser flash method on an LFA-457 instrument (Netzsch, Germany) at temperatures of 305-400 K. An equation is derived for the dependence of the molar heat capacities of the investigated esters on temperature. It is shown that the dependence of molar heat capacity C p,m (298.15 K) on n ( n = 1-6) is close to linear. The dependence of thermal diffusivity on temperature in the investigated temperature range is described by a first-degree polynomial, but thermal diffusivity a (298.15 K) as a function of n has a minimum at n = 5.

  19. Influence of heat treatment on antioxidant capacity and (poly)phenolic compounds of selected vegetables

    OpenAIRE

    Juaniz, I. (Isabel); Ludwig, I.A. (Iziar A.); Huarte, E; Pereira-Caro, G.; Moreno-Rojas, J.M.; Cid, C. (Concepción); Peña, M.P. (María Paz) de

    2016-01-01

    The impact of cooking heat treatments (frying in olive oil, frying in sunflower oil and griddled) on the antioxidant capacity and (poly)phenolic compounds of onion, green pepper and cardoon, was evaluated. The main compounds were quercetin and isorhamnetin derivates in onion, quercetin and luteolin derivates in green pepper samples, and chlorogenic acids in cardoon. All heat treatments tended to increase the concentration of phenolic compounds in vegetables suggesting a thermal destruction of...

  20. High Temperature Metal Hydrides as Heat Storage Materials for Solar and Related Applications

    Directory of Open Access Journals (Sweden)

    Borislav Bogdanović

    2009-01-01

    Full Text Available For the continuous production of electricity with solar heat power plants the storage of heat at a temperature level around 400 °C is essential. High temperature metal hydrides offer high heat storage capacities around this temperature. Based on Mg-compounds, these hydrides are in principle low-cost materials with excellent cycling stability. Relevant properties of these hydrides and their possible applications as heat storage materials are described.

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

    Science.gov (United States)

    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.

  2. 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%.

  3. Standing seats for high-capacity trains

    Directory of Open Access Journals (Sweden)

    Conor O’NEILL

    2014-10-01

    Full Text Available This paper details the design and potential implementation of standing seats in a commuter rail vehicle for the purposes of maximising capacity and revenue. The vehicle interior design is suited to the “Commuter Class” – a subset of travellers who travel primarily within the commuter belt and frequently utilise rail networks on a daily basis but require little additional space for luggage or peripherals. The concept delivers capacity increases in excess of 50% whilst still offering passengers a greater degree of personal space when compared with standing in aisles or gangways. The impact on vehicle stability and supporting intelligent systems are also discussed, delivering a unique design tailored specifically to meet the needs of the commuter class passenger.

  4. 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.)

  5. Liquid heat capacity of the solvent system (piperazine + 2-amino-2-methyl-l-propanol + water)

    Energy Technology Data Exchange (ETDEWEB)

    Chen, Y.-R. [R and D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); Caparanga, Alvin R.; Soriano, Allan N. [R and D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); School of Chemical Engineering and Chemistry, Mapua Institute of Technology, Intramuros, Manila 1002 (Philippines); Li, M.-H., E-mail: mhli@cycu.edu.t [R and D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China)

    2010-04-15

    This report presents a new set of heat capacity data for the system piperazine left brace(PZ) + 2-amino-2-methyl-1-propanol (AMP) + water (H{sub 2}O)right brace, measured using the differential scanning calorimetry technique, over the temperature range 303.2 K to 353.2 K and at fourteen (14) different concentrations in which the water mole fractions, x{sub 3}'s, were fixed at 0.60, 0.70, 0.80, and 0.90. Heat capacity for the binary system left bracePZ (1) + AMP (2)right brace at x{sub 1} = 0.05, 0.10, 0.15, and 0.20 were, likewise, measured to generate parameters necessary in the Redlich-Kister-type model, which was used to estimate excess molar heat capacities. Such estimates were then used to predict the values of the molar heat capacity at the corresponding sets of temperature and concentration. The predicted values were subsequently compared against the measured values and the results are satisfactory.

  6. THE HEAT CAPACITY OF FLUORINATED PROPANE AND BUTANE DERIVATIVES BY DIFFERENTIAL SCANNING CALORIMETRY

    Science.gov (United States)

    The paper gives results of the measurement (to 3% accuracy) of the constant-pressure liquid-phase heat capacities of 21 hydrogen-containing fluorinated propane and butane derivatives and one fluorinated ether (CF3OCF2H) with boiling points ranging from -34.6 to 76.7 C, using diff...

  7. Modeling the Heat Capacity of Spider Silk Inspired Di-block Copolymers

    Science.gov (United States)

    Huang, W.; Krishnaji, S.; Kaplan, D.; Cebe, P.

    2011-03-01

    We synthesized and characterized a new family of di-block copolymers based on the amino acid sequences of Nephila clavipes major ampulate dragline spider silk, having the form HABn and HBAn (n=1-6), comprising an alanine-rich hydrophobic block, A, a glycine-rich hydrophilic block, B, and a histidine tag, H. Using temperature modulated differential scanning calorimetry (TMDSC), we captured the effect of bound water acting as a plasticizer for copolymer films which had been cast from water solution and dried. We determined the water content by thermogravimetry and used the weight loss vs. temperature to correct the mass in TMDSC experiments. Our result shows that non-freezing bound water has a strong plasticization effect which lowers the onset of the glass transition by about 10circ; C. The reversing heat capacities, Cp(T), for temperatures below and above the glass transition were also characterized by TMDSC. We then calculated the solid state heat capacities of our novel block copolymers below the glass transition (Tg) based on the vibrational motions of the constituent poly(amino acid)s, whose heat capacities are known from the ATHAS Data Bank. Excellent agreement was found between the measured and calculated values of the heat capacity, showing that this model can serve as a standard method to predict the solid state Cp for other biologically inspired block copolymers. Support was provided from the NSF CBET-0828028 and the MRI Program under DMR-0520655 for thermal analysis instrumentation.

  8. Glass heat capacity and its abrupt change in glass transition region

    DEFF Research Database (Denmark)

    Yue, Yuanzheng; Smedskjær, Morten Mattrup; Mauro, John C.

    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) ...

  9. 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.

  10. 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…

  11. One-dimensional Simulation of Heat Structure Melting and Evaporation Under High Heat Flux Condition Using MARS

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Geon-Woo; Lee, Jeong-Hun; Cho, Hyoung-Kyu; Park, Goon-Cherl [Seoul National University, Seoul (Korea, Republic of); Im, Kihak [National Fusion Research Institute, Daejeon (Korea, Republic of)

    2016-10-15

    In order to establish the successful application for high heat flux condition, it is necessary to analyze material damage including possible phase change such as melting and evaporation due to high heat flux. In addition, in terms of coolant, water which is widely used for coolant has serious concern in that critical heat flux (CHF) occurrence can degrade the cooling capability and aggravate the integrity of cooling components. However, MARS code cannot simulate the melting and evaporation of materials under high heat flux or heat generation condition by itself due to the absence of those models. In the present study, therefore, one dimensional heat conduction calculation module for heat structure melting and evaporation was developed and coupled with MARS to overcome the limitation of material phase change simulation capability in MARS code. As clarifying the high heat flux problem, plasma facing component of Korean demonstration fusion reactor, K-DEMO, was selected. The one-dimensional simulation of melting and evaporation of high heat flux component was performed using MARS and newly developed phase change simulation module. The target component and high heat flux condition were referred to geometry of plasma facing component in Korean fusion demonstration plant and fusion reactor's plasma disruption event. In order to simulate melting and evaporation, effective heat capacity method and evaporation model were applied to phase change simulation module. The simulation results showed several phenomena such as melting, evaporation and CHF occurrence in coolant channel.

  12. Thermodynamic functions of ZrW2O8 from its heat capacity

    Science.gov (United States)

    Ji, FengMin; Dai, XianXi; Stevens, R.; Goates, J. B.

    2012-04-01

    It is interesting to maximize the amount of information we can obtain from one experiment on a single sample. In obtaining all the thermodynamic properties of some materials from their experimental heat capacity data only, we aim to get the temperature- independent energy spectrum. However, all the practical measured energy spectra depend on the temperature of experiments. One promising method to obtain the temperature-independent energy spectrum is to solve the so-called specific heat-phonon spectrum inversion (SPI) problem. Here we show, by developing a new practical solution method of SPI, the phonon spectrum of the negative thermal expansion material ZrW2O8 is obtained. This phonon spectrum is temperature- independent and almost method independent. Hence all the thermodynamic properties of ZrW2O8, such as thermodynamic potential, entropy, Helmholtz free energy, etc. are obtained by heat capacity only.

  13. Purex Plant flowsheet for high capacity study

    Energy Technology Data Exchange (ETDEWEB)

    Geier, R.G.; Duckworth, J.P.

    1960-03-28

    This report contains a flowsheet which was prepared to serve as a guide for an engineering study to be made to determine the costs and revisions required to increase the capacity of the Purex Plant to a 4.0 capacity factor. The needs for such a study are outlined in documents HW-62952 (Ref. 1) and HW-63927 (Ref. 2), which include increased 100 Area production forecasts and maximizing Palm recovery by continuous recovery equipment as primary factors. The flowsheet, shown graphically on the flowsketch and specifically in tabular form under Table 1, is a ``best estimate`` of process conditions and modifications which will be in operation by the third quarter of FY 1962. The modifications included are: Formaldehyde Treatment of Concentrated Wastes -- IWW (Ref. 5 and 6); A Continuous Palm Recovery Cycle; A Palm Ion Exchange Purification and Loadout Facility (Ref. 3); Alkaline-Permanganate Washing of the No. 2 Organic System Solvent; and Rough-cut Fission Product Recovery and Shipping (Ref. 4). Since the fission product recovery and shipping operations do not effect the equilibrium conditions of the plant, they are not included in the flowsheet.

  14. 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.

  15. 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.

  16. 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.

  17. 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

    for 86 types of substances) included fatty compounds, such as fatty acids, esters, alcohols and triacylglycerols, and hydrocarbons. The performance of this method is compared with other published group contribution methods [Z. Kolska, J. Kukal, M. Zabransky, V. Ruzicka Ind. Eng. Chem. Res. 47 (2008) 2075......-2085] and the Rowlinson-Bondi equation. Also, the predictive performance of general correlations of heats of vaporization based on the corresponding-states method, such as Carruth and Kobayashi [G.F. Carruth, R. Kobayashi, Ind. Eng. Chem. Fundam. 11 (1972) 509-516], Sivaraman et al. [A. Sivaraman, J.W. Magee, R...... in the prediction of heats of vaporization of fatty compounds based on the vapor pressure model of Ceriani and Meirelles [R. Ceriani. A.J.A. Meirelles, Fluid Phase Equilib. 215 (2004) 227-236] and its combination with the Clausius-Clapeyron equation has been Studied. (C) 2009 Elsevier B.V. All rights reserved....

  18. High-efficiency Commercial Cold Climate Heat Pump

    Energy Technology Data Exchange (ETDEWEB)

    Mahmoud, Ahmad M. [United Technologies Research Center, East Hartford, CT (United States); Cogswell, F. [United Technologies Research Center, East Hartford, CT (United States); Verma, P. [United Technologies Research Center, East Hartford, CT (United States)

    2015-08-28

    United Technologies Research Center (UTRC) proposed in 2012 to design, develop and demonstrate an air-source 10TR high-efficiency commercial cold climate heat pump (CCCHP). The proposed heat pump would be scalable beyond 40TR, cost effective with a simple payback of < 3 years upon commercialization and would reduce annual electricity use for building space heating in cold climates by at least 20%. This would represent an annual savings of $2.3 billion and a 20% displacement of total greenhouse gases generated upon full commercialization. The primary objective was to develop a highly integrated system that shall meet or exceed DOE capacity and efficiency targets at key conditions and is scalable, cost-effective and simple relative to the state-of-the-art. Specifically, the goal of the project was to design, develop and demonstrate a CCCHP that exceeds DOE capacity degradation requirements at +17F and -13F conditions (0 and <15% degradation vs. 10 and 25% DOE requirements, respectively) while meeting or exceeding DOE capacity and system efficiency requirements at all other conditions.

  19. Data acquisition of space heat demand with high spatial resolution. Digital heat demand map; Erfassung des raeumlich hoch aufgeloesten Raumwaermebedarfs. Digitale Waermebedarfskarte

    Energy Technology Data Exchange (ETDEWEB)

    Blesl, Markus; Kempe, Stephan [Stuttgart Univ. (DE). Inst. fuer Energiewirtschaft und Rationelle Energieanwendung (IER); Huther, Heiko [AGFW - Der Energieeffizienzverband fuer Waerme, Kaelte und KWK e. V., Frankfurt am Main (Germany)

    2010-01-15

    For a selective and systematic expansion of the district heating capacity, detailed knowledge of the heat demand of a given town district is required. For this, a method was developed for automatic data acquisition of the space heat demand of an urban area with high spatial resolution. The method was applied exemplarily to the inner city of the town of Esslingen. (orig.)

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

    Energy Technology Data Exchange (ETDEWEB)

    Khan, M. F.; Miriyala, N.; Hassanpourfard, M.; Thundat, T. [Ingenuity Lab, Edmonton, Alberta T6G 2R3 (Canada); Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2R3 (Canada); Lee, J. [Department of Chemical and Materials Engineering, University of Alberta, Edmonton, Alberta T6G 2R3 (Canada); Department of Mechanical Engineering, Sogang University, 121-742 Seoul (Korea, Republic of); Kumar, A. [Department of Mechanical Engineering, University of Alberta, Edmonton, Alberta T6G 2R3 (Canada)

    2016-05-23

    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{sup −1 }K{sup −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.

  1. High-temperature heat-pump fluids

    Science.gov (United States)

    Bertinat, M. P.

    1988-05-01

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

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2001-05-18

    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 <5kW. Even at the maximum demonstrated average powers, the output is most often delivered as continuous wave (CW) or as small energy pulses at high pulse repetition frequency (PRF) and the beam divergence is typically >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

  3. Native and Heated Hydrolysates of Milk Proteins and Their Capacity to Inhibit Lipid Peroxidation in the Zebrafish Larvae Model.

    Science.gov (United States)

    Carrillo, Wilman; Guzmán, Xavier; Vilcacundo, Edgar

    2017-09-14

    Casein and whey proteins with and without heat treatment were obtained of whole milk and four commercial milks in Ecuador, and were hydrolyzed. Then, their capacity to inhibit the lipid peroxidation using the TBARS method was evaluated at concentrations of 0.02, 0.04, 0.2, and, 0.4 mg/mL. Native and heated hydrolysates of milk proteins present high inhibitions of lipid peroxidation with a dose dependent effect both in vivo and in vitro tests. Casein and whey proteins obtained from whole milk were the ones with the highest anti-oxidant activity in vitro and in vivo test. Native casein hydrolysate at 0.4 mg/mL present a value of 55.55% of inhibition of lipid peroxidation and heated casein hydrolysate at 0.4 mg/mL presents a value of 58.00% of inhibition of lipid peroxidation. Native whey protein at 0.4 mg/mL present a value of 34.84% of inhibition of lipid peroxidation, and heated whey protein at 0.4 mg/mL presents a value of 40.86% of inhibition of lipid peroxidation. Native and heated casein hydrolysates were more active than native and heated whey protein hydrolysates. Heat treatments have an effect of increasing the in vitro inhibition of lipid peroxidation of hydrolysates of milk protein. Casein and whey hydrolysates were able to inhibiting lipid peroxidation in the zebrafish larvae model. Native casein hydrolysate obtained of whole milk presents 48.35% of inhibition TBARS in vivo, this activity was higher in heated casein hydrolysate obtained of whole milk with a value of 56.28% of inhibition TBARS in vivo. Native whey protein hydrolysate obtained of whole milk presents 35.30% of inhibition TBARS, and heated whey protein hydrolysate obtained of whole milk was higher, with a value of 43.60% of inhibition TBARS in vivo.

  4. Excess heat capacity and entropy of mixing along the chlorapatite-fluorapatite binary join

    Science.gov (United States)

    Dachs, Edgar; Harlov, Daniel; Benisek, Artur

    2010-10-01

    The heat capacity at constant pressure, C p, of chlorapatite [Ca5(PO4)3Cl - ClAp], and fluorapatite [Ca5(PO4)3F - FAp], as well as of 12 compositions along the chlorapatite-fluorapatite join have been measured using relaxation calorimetry [heat capacity option of the physical properties measurement system (PPMS)] and differential scanning calorimetry (DSC) in the temperature range 5-764 K. The chlor-fluorapatites were synthesized at 1,375-1,220°C from Ca3(PO4)2 using the CaF2-CaCl2 flux method. Most of the chlor-fluorapatite compositions could be measured directly as single crystals using the PPMS such that they were attached to the sample platform of the calorimeter by a crystal face. However, the crystals were too small for the crystal face to be polished. In such cases, where the sample coupling was not optimal, an empirical procedure was developed to smoothly connect the PPMS to the DSC heat capacities around ambient T. The heat capacity of the end-members above 298 K can be represented by the polynomials: C {p/ClAp} = 613.21 - 2,313.90 T -0.5 - 1.87964 × 107 T -2 + 2.79925 × 109 T -3 and C {p/FAp} = 681.24 - 4,621.73 × T -0.5 - 6.38134 × 106 T -2 + 7.38088 × 108 T -3 (units, J mol-1 K-1). Their standard third-law entropy, derived from the low-temperature heat capacity measurements, is S° = 400.6 ± 1.6 J mol-1 K-1 for chlorapatite and S° = 383.2 ± 1.5 J mol-1 K-1 for fluorapatite. Positive excess heat capacities of mixing, Δ C {p/ex}, occur in the chlorapatite-fluorapatite solid solution around 80 K (and to a lesser degree at 200 K) and are asymmetrically distributed over the join reaching a maximum of 1.3 ± 0.3 J mol-1 K-1 for F-rich compositions. They are significant at these conditions exceeding the 2 σ-uncertainty of the data. The excess entropy of mixing, Δ S ex, at 298 K reaches positive values of 3-4 J mol-1 K-1 in the F-rich portion of the binary, is, however, not significantly different from zero across the join within its 2 σ-uncertainty.

  5. The Stone-Wales transformation: from fullerenes to graphite, from radiation damage to heat capacity.

    Science.gov (United States)

    Heggie, M I; Haffenden, G L; Latham, C D; Trevethan, T

    2016-09-13

    The Stone-Wales (SW) transformation, or carbon-bond rotation, has been fundamental to understanding fullerene growth and stability, and ab initio calculations show it to be a high-energy process. The nature and topology of the fullerene energy landscape shows how the Ih-C60 must be the final product, if SW transformations are fast enough, and various mechanisms for their catalysis have been proposed. We review SW transformations in fullerenes and then discuss the analogous transformation in graphite, where they form the Dienes defect, originally posited to be a transition state in the direct exchange of a bonded atom pair. On the basis of density functional theory calculations in the local density approximation, we propose that non-equilibrium concentrations of the Dienes defect arising from displacing radiation are rapidly healed by point defects and that equilibrium concentrations of Dienes defects are responsible for the divergent ultra-high-temperature heat capacity of graphite.This article is part of the themed issue 'Fullerenes: past, present and future, celebrating the 30th anniversary of Buckminster Fullerene'. © 2016 The Author(s).

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

    Directory of Open Access Journals (Sweden)

    Sira Maria Karvinen

    2016-07-01

    Full Text Available 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 body temperature. Here we use rat models that differ for maximal running capacity (Low capacity runners, LCR and High capacity Runners, HCR to study the connection between PA and body temperature. Ten HCR and ten LCR female rats were studied between 9 and 21 months of age. Rectal temperature of HCR and LCR rats was measured before and after one 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 < 0.001. Aging decreased the body temperature level of HCRs to similar levels with LCRs. The opportunity to run voluntarily had a marked impact on the body temperature of HCRs (p < 0.001 allowing them to maintain body 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 contents in the skeletal muscle (p < 0.050. These results suggest that higher PA level together with greater relative muscle mass and higher mitochondrial content/function contribute to the accumulation of heat in the HCRs. Interestingly, neither aging nor voluntary training had a significant impact on core body temperature of LCRs. However, glucose injection resulted in a lowering of the body temperature of LCRs (p < 0.050, but not that of HCRs. In conclusion, rats born with high intrinsic aerobic capacity and better health have higher body temperature compared to rats born with low aerobic

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

    KAUST Repository

    Chaaban, Anas

    2017-06-01

    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 lower and upper bounds for this channel. To this end, capacity lower bounds are developed by deriving the achievable rates of two precoding-free 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. For a channel with 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.

  8. High-Capacity, High-Voltage Composite Oxide Cathode Materials

    Science.gov (United States)

    Hagh, Nader M.

    2015-01-01

    This SBIR project integrates theoretical and experimental work to enable a new generation of high-capacity, high-voltage cathode materials that will lead to high-performance, robust energy storage systems. At low operating temperatures, commercially available electrode materials for lithium-ion (Li-ion) batteries do not meet energy and power requirements for NASA's planned exploration activities. NEI Corporation, in partnership with the University of California, San Diego, has developed layered composite cathode materials that increase power and energy densities at temperatures as low as 0 degC and considerably reduce the overall volume and weight of battery packs. In Phase I of the project, through innovations in the structure and morphology of composite electrode particles, the partners successfully demonstrated an energy density exceeding 1,000 Wh/kg at 4 V at room temperature. In Phase II, the team enhanced the kinetics of Li-ion transport and electronic conductivity at 0 degC. An important feature of the composite cathode is that it has at least two components that are structurally integrated. The layered material is electrochemically inactive; however, upon structural integration with a spinel material, the layered material can be electrochemically activated and deliver a large amount of energy with stable cycling.

  9. Reaction heats and heat capacity changes for intermediate steps of the ATP hydrolysis catalyzed by myosin subfragment 1.

    Science.gov (United States)

    Kodama, T

    1981-03-25

    The interaction of myosin Subfragment 1 with ATP in 0.1 M KCl containing 0.01 M MgCl2 and 0.02 M Tris/HCl (pH 8.0) was studied by microcalorimetry at temperatures of 4, 12, and 23 degrees C so that values of the heat capacity change (delta Cp) could be obtained for intermediate steps of the ATPase cycle. The delta Cp values are large compared to the value for the overall cycle, indicating that large changes in the hydrophobic effect are involved in transitions between different intermediate states. However, the heat capacity changes themselves show peculiar temperature dependences. Thus bindings of ATP and ADP to Subfragment 1, both of which are strongly exothermic processes, take place with large negative delta Cp of about -3 kJK-1 mol-1 between 4 and 12 degrees C but with very small delta Cp of 0.3-0.4 kJ K-1 mol-1 between 12 and 23 degrees C. On the contrary, the delta Cp for the endothermic hydrolysis of ATP bound to Subfragment 1 is positive (congruent to kJK-1 mol-1) in the lower temperature range but strongly negative (congruent to -4 kJK-1 mol-1) in the higher temperature range. The magnitude of delta Cp for the slow Pi dissociation process is similar but its sign is just opposite to that for the hydrolysis. These anomalous changes in the heat capacity may be due to the temperature-induced changes in a balance between large opposing effects which result from distinct, local conformation changes within the Subfragment 1 molecule.

  10. Novel Anthropometry-Based Calculation of the Body Heat Capacity in the Korean Population.

    Directory of Open Access Journals (Sweden)

    Duong Duc Pham

    Full Text Available Heat capacity (HC has an important role in the temperature regulation process, particularly in dealing with the heat load. The actual measurement of the body HC is complicated and is generally estimated by body-composition-specific data. This study compared the previously known HC estimating equations and sought how to define HC using simple anthropometric indices such as weight and body surface area (BSA in the Korean population. Six hundred participants were randomly selected from a pool of 902 healthy volunteers aged 20 to 70 years for the training set. The remaining 302 participants were used for the test set. Body composition analysis using multi-frequency bioelectrical impedance analysis was used to access body components including body fat, water, protein, and mineral mass. Four different HCs were calculated and compared using a weight-based HC (HC_Eq1, two HCs estimated from fat and fat-free mass (HC_Eq2 and HC_Eq3, and an HC calculated from fat, protein, water, and mineral mass (HC_Eq4. HC_Eq1 generally produced a larger HC than the other HC equations and had a poorer correlation with the other HC equations. HC equations using body composition data were well-correlated to each other. If HC estimated with HC_Eq4 was regarded as a standard, interestingly, the BSA and weight independently contributed to the variation of HC. The model composed of weight, BSA, and gender was able to predict more than a 99% variation of HC_Eq4. Validation analysis on the test set showed a very high satisfactory level of the predictive model. In conclusion, our results suggest that gender, BSA, and weight are the independent factors for calculating HC. For the first time, a predictive equation based on anthropometry data was developed and this equation could be useful for estimating HC in the general Korean population without body-composition measurement.

  11. Development of energy efficient smart module with variable direction of heat flow, heat capacity and surface absorptivity(I)

    Energy Technology Data Exchange (ETDEWEB)

    Chun, W.K.; Lee, Y.J.; Lee, H.J. [Jeju University, Jeju (Korea, Republic of)] [and others

    1996-02-01

    This work has been carried out to develop thermal diode modules with variable direction of heat flow, heat capacity and surface absorptivity. The module can be used for space heating in winter and reduce the cooling load of buildings in summer. this concept could be also utilized for domestic hot water heating. The modules are categorized as follows; (1) Loop Type Smart Module, (2) Bayonet Type Smart Module, (3) Roller Type Smart Module, (4) Plane Tubeless Solar Collector and Storage System Utilizing the Bayonet Concept. Each system generally features either or both of the passive or active schemes. The Loop Type, in particular, is designed with the photo diode and microprocessor to harness the solar energy more aggressively. It is essential to contrive a totally new design concept apart from conventional ones to fully appreciate the availability of the sun`s energy. In this regard, the solar modules under investigation in the present study is of great significance. (author) 29 refs., 65 figs., 5 photos.

  12. Dynamic heat capacity of the east model and of a bead-spring polymer model.

    Energy Technology Data Exchange (ETDEWEB)

    McCoy, John Dwane (New Mexico Institute of Mining and Technology, Socorro, NM); Brown, Jonathan R. (New Mexico Institute of Mining and Technology, Socorro, NM); Adolf, Douglas Brian

    2011-10-01

    In this report we have presented a brief review of the glass transition and one means of characterizing glassy materials: linear and nonlinear thermodynamic oscillatory experiments to extract the dynamic heat capacity. We have applied these methods to the east model (a variation of the Ising model for glass forming systems) and a simple polymeric system via molecular dynamics simulation, and our results match what is seen in experiment. For the east model, since the dynamics are so simple, a mathematical model is developed that matches the simulated dynamics. For the polymeric system, since the system is a simulation, we can instantaneously 'quench' the system - removing all vibrational energy - to separate the vibrational dynamics from dynamics associated with particle rearrangements. This shows that the long-time glassy dynamics are due entirely to the particle rearrangements, i.e. basin jumping on the potential energy landscape. Finally, we present an extension of linear dynamic heat capacity to the nonlinear regime.

  13. Magnetic susceptibility and heat capacity of graphene in two-band Harrison model

    Science.gov (United States)

    Mousavi, Hamze; Bagheri, Mehran; Khodadadi, Jabbar

    2015-11-01

    Using a two-band tight-binding Harrison model and Green's function technique, the influences of both localized σ and delocalized π electrons on the density of states, the Pauli paramagnetic susceptibility, and the heat capacity of a graphene sheet are investigated. 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 diamagnetism in graphene-based nanosystems, a paramagnetic behavior associated with the itinerant π electrons could be occurred. Further, we report a Schottky anomaly in the heat capacity. This study asserts that the contribution of both σ and π electrons play dominant roles in the mentioned physical quantities.

  14. Vibrational Spectra and Heat Capacity of Methane, and the Speed of Sound

    Science.gov (United States)

    Tennis, Ronald; Bailey, Ryan; Henderson, Giles

    2000-12-01

    A two-part physical chemistry laboratory experiment is described in which students evaluate statistical mechanical theory by comparing a measured speed of sound and heat capacity with values predicted from vibrational spectra. In part 1 students measure the IR spectrum of CH4(g) and the Raman spectrum of CH4(l) to determine quantized vibrational energy spacings. Strong Raman scattering of a pulsed nitrogen laser beam is observed with a liquid methane sample in a custom cryogenic cell constructed from two side-arm test tubes and a length of Pyrex tube. These data are used with the statistical mechanics of a harmonic oscillator to calculate vibrational heat capacities and CP/CV; of CH4(g) and the speed of sound in CH4(g). In part 2, the predicted speed of sound is compared with an experimental value measured with a simple acoustic resonance cavity (Kundt's tube) exhausted to a Bunsen burner.

  15. Exploring the Characteristics of Principals in High Leadership Capacity Schools

    Science.gov (United States)

    Bergstrom, Leslie C.

    2011-01-01

    This qualitative study examines the characteristics of principals in high leadership capacity schools. Lambert (1998) defines leadership capacity as broad-based, skillful participation in the work of leadership. Data were collected from a total of nine study participants, one Assistant Superintendent, two principals, and six certified professional…

  16. Large-scale calculations of gas phase thermochemistry : Enthalpy of formation, standard entropy, and heat capacity

    OpenAIRE

    Ghahremanpour, Mohammad M.; van Maaren, Paul J.; Ditz, Jonas C.; Lindh, Roland; van der Spoel, David

    2016-01-01

    Large scale quantum calculations for molar enthalpy of formation (Delta(f) H-0), standard entropy (S-0), and heat capacity (C-V) are presented. A large data set may help to evaluate quantum thermochemistry tools in order to uncover possible hidden shortcomings and also to find experimental data that might need to be reinvestigated, indeed we list and annotate approximately 200 problematic thermochemistry measurements. Quantum methods systematically underestimate S-0 for flexible molecules in ...

  17. 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.

  18. Heat Capacity Measurements of Sr2RuO4 Under Uni-axial Stress

    Science.gov (United States)

    Li, You-Sheng; Gibbs, Alexandra; MacKenzie, Andrew; Hicks, Clifford; Nicklas, Michael

    One of the most-discussed possible pairing symmetries of the superconductor Sr2RuO4 is px + /-ipy. By applying in-plane uniaxial stress, the degeneracy of the px and py components should be lifted, yielding two critical temperatures (Tc) . Hicks et al. observed an increase of Tc of Sr2RuO4 under both compressive and tensile stress, and did not find evidence for splitting of transition. However, that result was based on magnetic susceptibility measurements, which would be sensitive only to the upper transition. For a direct test of possible splitting, we measure the heat capacity of Sr2RuO4 under uniaxial stress. To do so, we have developed an approach to measure heat capacity under non-adiabatic conditions. We have observed the increase in Tc under compressive strain, providing the first thermodynamic evidence for the strain-induced increase in Tc of Sr2RuO4, and also resolve strong strain-induced changes in the normal-state heat capacity.

  19. Improved exercise capacity in the heat followed by coconut water consumption

    Directory of Open Access Journals (Sweden)

    Orlando Laitano

    2014-03-01

    Full Text Available The aim of the present study was to assess the effects of prior ingestion of coconut water on fluid retention and exercise capacity in the heat as well as signs of gastrointestinal distress. Eight physically active men were recruited (age 23 ± 3 years, height 176 ± 6 cm, body mass 78 ± 7 kg and performed three exercise capacity trials on a cycle ergometer in the heat (34 ± 1°C after the ingestion of one of the following drinks: a plain water (PW, b flavored drink (FD, and c coconut water (CW. Ingestion of CWresulted in a longer time to exhaustion (p=0.029. Likewise, participants achieved a higher heart rate in the CW session when compared to the other trials (PW 183 ± 5 bpm, FD 184 ± 8 bpm, and CW 189 ± 8 bpm, p<0.05 and a reduced urine output after the coconut water ingestion (PW 214 ± 85 ml, FD 267 ± 90 ml, and CW 161 ± 73 ml, p<0.05 indicating a higher fluid retention of coconut water in comparison to plain water and the flavored drink. These results demonstrate that previous ingestion of coconut water improves exercise capacity in the heat and provide a reduced urine output in comparison to plain water and flavored drink. Also there is no evidence for GI distress.

  20. Prevalence of Temperature Dependent Heat Capacity Changes in Protein-DNA Interactions

    Energy Technology Data Exchange (ETDEWEB)

    Liu, C.-C.; Richard, A.J.; Kausiki, D.; LiCata, V.J.

    2009-05-19

    A large, negative {Delta}Cp of DNA binding is a thermodynamic property of the majority of sequence-specific DNA-protein interactions, and a common, but not universal property of non-sequence-specific DNA binding. In a recent study of the binding of Taq polymerase to DNA, we showed that both the full-length polymerase and its 'Klentaq' large fragment bind to primed-template DNA with significant negative heat capacities. Herein, we have extended this analysis by analyzing this data for temperature-variable heat capacity effects ({Delta}{Delta}Cp), and have similarly analyzed an additional 47 protein-DNA binding pairs from the scientific literature. Over half of the systems examined can be easily fit to a function that includes a {Delta}{Delta}Cp parameter. Of these, 90% display negative {Delta}{Delta}Cp values, with the result that the {Delta}Cp of DNA binding will become more negative with rising temperature. The results of this collective analysis have potentially significant consequences for current quantitative theories relating {Delta}Cp values to changes in accessible surface area, which rely on the assumption of temperature invariance of the {Delta}Cp of binding. Solution structural data for Klentaq polymerase demonstrate that the observed heat capacity effects are not the result of a coupled folding event.

  1. Photovoltaics for high capacity space power systems

    Science.gov (United States)

    Flood, Dennis J.

    1988-01-01

    The anticipated energy requirements of future space missions will grow by factors approaching 100 or more, particularly as a permanent manned presence is established in space. The advances that can be expected in solar array performance and lifetime, when coupled with advanced, high energy density storage batteries and/or fuel cells, will continue to make photovoltaic energy conversion a viable power generating option for the large systems of the future. The specific technologies required to satisfy any particular set of power requirements will vary from mission to mission. Nonetheless, in almost all cases the technology push will be toward lighter weight and higher efficiency, whether of solar arrays of storage devices. This paper will describe the content and direction of the current NASA program in space photovoltaic technology. The paper will also discuss projected system level capabilities of photovoltaic power systems in the context of some of the new mission opportunities under study by NASA, such as a manned lunar base, and a manned visit to Mars.

  2. Radiation Tolerant, High Capacity Non-Volatile Memory Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The need for reliable, high capacity, radiation tolerant nonvolatile memory exists in many Human space flight applications. Most projects rely on COTS hardware for a...

  3. 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.

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

    Energy Technology Data Exchange (ETDEWEB)

    Lin Peiyin [R and D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); Soriano, Allan N. [R and D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); School of Chemical Engineering and Chemistry, Mapua Institute of Technology, Manila 1002 (Philippines); Leron, Rhoda B. [R and D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China); Li Menghui, E-mail: mhli@cycu.edu.t [R and D Center for Membrane Technology and Department of Chemical Engineering, Chung Yuan Christian University, Chung Li 32023, Taiwan (China)

    2010-08-15

    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.

  5. An adiabatic calorimeter for heat capacity measurements of polyurethane foam with blowing agent of HFC245fa in the temperature range 60-290K

    Energy Technology Data Exchange (ETDEWEB)

    Yang, C.G.; Xu, L.; Zhang, L.Q.; Chen, N. [Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200030 (China)

    2006-06-15

    In order to meet the urgent need of heat insulating materials used under low temperature in the area of aerospace, a new polyurethane (PU) foam with HFC245fa as blowing agent was developed. In this paper, the heat capacity in the temperature range of 60-290K of the new material was measured through an automated adiabatic calorimeter, which was composed of a heat insulation system, a power measuring system, a vacuum pumping system and a cooling system. The sample cell of the calorimeter was equipped with a miniature platinum thermometer surrounded by two adiabatic shields and housed in a high vacuum can. The temperature differences among the sample cell and the inner and outer adiabatic shields could be adjusted automatically to less than 0.05K, all which ensure there was no heat exchange between the sample and surroundings. Under these conditions, the mathematical formulation of the sample with the physical model was given. Through measuring the heat capacity of {alpha}-Al{sub 2}O{sub 3}, which is a standard reference material, a relatively high reliability with a deviation of +/-2.5% of this adiabatic calorimeter was shown compared with the standard data. The results indicate that the newly developed PU foam has a higher heat capacity compared with other heat insulating materials, and there is no obvious sign of any phase transition or thermal anomaly in the entire temperature range. That is to say, the material is thermodynamically stable when used in the low temperature range. (author)

  6. An adiabatic calorimeter for heat capacity measurements of polyurethane foam with blowing agent of HFC245fa in the temperature range 60-290 K

    Energy Technology Data Exchange (ETDEWEB)

    Yang, C.G. [Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200030 (China)]. E-mail: chunguang_yang@sjtu.edu.cn; Xu, L. [Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200030 (China); Zhang, L.Q. [Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200030 (China); Chen, N. [Institute of Refrigeration and Cryogenics, Shanghai Jiao Tong University, Shanghai 200030 (China)

    2006-06-15

    In order to meet the urgent need of heat insulating materials used under low temperature in the area of aerospace, a new PU foam with HFC245fa as blowing agent was developed. In this paper, the heat capacity in the temperature range of 60-290 K of the new material was measured through an automated adiabatic calorimeter, which was composed of a heat insulation system, a power measuring system, a vacuum pumping system and a cooling system. The sample cell of the calorimeter was equipped with a miniature platinum thermometer surrounded by two adiabatic shields and housed in a high vacuum can. The temperature differences among the sample cell and the inner and outer adiabatic shields could be adjusted automatically to less than 0.05 K, all which ensure there was no heat exchange between the sample and surroundings. Under these conditions, the mathematical formulation of the sample with the physical model was given. Through measuring the heat capacity of {alpha}-Al{sub 2}O{sub 3}, which is a standard reference material, a relatively high reliability with a deviation of {+-}2.5% of this adiabatic calorimeter was shown compared with the standard data. The results indicate that the newly developed PU foam has a higher heat capacity compared with other heat insulating materials, and there is no obvious sign of any phase transition or thermal anomaly in the entire temperature range. That is to say, the material is thermodynamically stable when used in the low temperature range.

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

    Directory of Open Access Journals (Sweden)

    Jun Moriya

    Full Text Available 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.

  8. 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. PMID:22496783

  9. 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

    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...... 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...

  10. Cryostat for semiautomatic measurement of heat capacity and elastic moduli between 1.6 and 400 K

    Science.gov (United States)

    Hirao, Kazuyuki; Soga, Naohiro

    1983-11-01

    An adiabatic cryostat system for the measurement of either heat capacity or elastic moduli was constructed. The vacuum system, electronic equipment to achieve the adiabatic conditions, and instruments for measurements are described. The cube resonance method used for measurement of elastic moduli is shown. Test measurements on the heat capacity of α-Al2O3 show agreement within ±1% of the literature values. The results of heat capacity and elastic moduli measurements on optical fiberglass are described and compared with other data.

  11. Industrial Heat Pump for a High Temperature District Heating Application

    DEFF Research Database (Denmark)

    Poulsen, Claus Nørgaard

    by excess thermal energy from thermal solar panels. An industrial heat pump system using the natural refrigerant ammonia, is extracting the thermal energy from the storage when needed, and produce hot water at 85°C, for the district heating grid. The heat pump also acts as contributor to electricity grid...

  12. 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.

  13. Rapid Heat Treatment of Aluminum High-Pressure Diecastings

    Science.gov (United States)

    Lumley, R. N.; Polmear, I. J.; Curtis, P. R.

    2009-07-01

    Recently, it has been demonstrated that common high-pressure diecasting (HPDC) alloys, such as those based on the Al-Si-Cu and Al-Si-Mg-(Cu) systems, may be successfully heat treated without causing surface blistering or dimensional instability. In some compositions, the capacity to exploit age hardening may allow the proof stress values to be doubled when compared to the as-cast condition. This heat treatment procedure involves the use of severely truncated solution treatment cycles conducted at lower than normal temperatures, followed by quenching and natural or artificial aging. The potential therefore exists to develop and evaluate secondary HPDC alloys designed specifically for rapid heat treatment, while still displaying high castability. This article reports results of an experimental program in which responses of various alloy compositions to age hardening have been investigated with the primary aim of further reducing the duration and cost of the heat treatment cycle while maintaining high tensile properties. Composition ranges have been established for which values of 0.2 pct proof stress exceeding 300 MPa ( i.e., increases of ~100 pct above as-cast values) can be achieved using a procedure that involves a total time for solution treatment plus age hardening of only 30 minutes. This rapid aging behavior is shown to be related to precipitation of the complex Q' phase, which forms primarily when Mg contents of the alloys are above ~0.2 wt pct.

  14. Cooling capacity of high porosity open-cell metal foams as passive cryogenic radiators

    Science.gov (United States)

    Dixit, Tisha; Ghosh, Indranil

    2017-06-01

    This work presents an innovative avenue for employment of high porosity open-cell metal foams as extended heat transfer surfaces in passive cryogenic radiators. Metal foams are known for being light in weight and possess high surface area density. In contrast to a solid surface, porosity of metal foams makes it feasible for penetration of radiation thereby resulting in higher radiatively interactive surface area. Two 20 PPI metal foams made of copper and aluminum with 94.9% and 90.3% porosity respectively have been chosen for this study. A laboratory-scale test rig measures the radiative cooling capacity of metal foams in vacuum (10-6 mbar) subjected to liquid nitrogen environment. Heat load to the foam has been provided by means of convective fluid loop. Simultaneously, a theoretical model based on radiation-conduction fin analysis has been developed to predict the foam cooling capacity at a specified temperature. The required radiation heat transfer coefficient has been obtained from a previous experiment wherein the foam samples are freely suspended in similar conditions but with no heat load. Lastly, performance of the foams under study has been expressed in terms of a commonly used performance parameter (surface area/cooling capacity) for passive cryogenic radiators.

  15. Molar Heat Capacity (Cv) for Saturated and Compressed Liquid and Vapor Nitrogen from 65 to 300 K at Pressures to 35 MPa.

    Science.gov (United States)

    Magee, J W

    1991-01-01

    Molar heat capacities at constant volume (Cv ,) for nitrogen have been measured with an automated adiabatic calorimeter. The temperatures ranged from 65 to 300 K, while pressures were as high as 35 MPa. Calorimetric data were obtained for a total of 276 state conditions on 14 isochores. Extensive results which were obtained in the saturated liquid region (Cv((2)) and Cσ ) demonstrate the internal consistency of the Cv (ρ,T) data and also show satisfactory agreement with published heat capacity data. The overall uncertainty of the Cv values ranges from 2% in the vapor to 0.5% in the liquid.

  16. Thermodynamic properties of zeolites: low-temperature heat capacities and thermodynamic functions for phillipsite and clinoptilolite. Estimates of the thermochemical properties of zeolitic water at low temperature.

    Science.gov (United States)

    Hemingway, B.S.; Robie, R.A.

    1984-01-01

    Measured heat capacities between 15 and 305 K and calculated heat capacities, entropies, enthalpy functions and Gibbs energy functions are reported and analysed for phillipsite and clinoptilolite. - J.A.Z.

  17. 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

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

    National Research Council Canada - National Science Library

    R. Pässler

    2017-01-01

    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...

  19. Holographic memory module with ultra-high capacity and throughput

    Energy Technology Data Exchange (ETDEWEB)

    Vladimir A. Markov, Ph.D.

    2000-06-04

    High capacity, high transfer rate, random access memory systems are needed to archive and distribute the tremendous volume of digital information being generated, for example, the human genome mapping and online libraries. The development of multi-gigabit per second networks underscores the need for next-generation archival memory systems. During Phase I we conducted the theoretical analysis and accomplished experimental tests that validated the key aspects of the ultra-high density holographic data storage module with high transfer rate. We also inspected the secure nature of the encoding method and estimated the performance of full-scale system. Two basic architectures were considered, allowing for reversible compact solid-state configuration with limited capacity, and very large capacity write once read many memory system.

  20. Exercise capacity in the heat is greater in the morning than in the evening in man.

    Science.gov (United States)

    Hobson, Ruth M; Clapp, Emma L; Watson, Phillip; Maughan, Ronald J

    2009-01-01

    This study investigated the effect of time of day on endurance exercise capacity in a warm environment. Nine males cycled to exhaustion at 65% .VO2peak in an ambient temperature of 35 degrees C (60% relative humidity) at 0645 h (AM) and 1845 h (PM). Rectal temperature (Tc), skin temperature (Tsk), and heart rate (HR) were recorded and blood and expired air samples collected at rest every 5 min during exercise and during recovery. Time to exhaustion was longer in the AM trial (45.8 +/- 10.7 min) than in the PM trial (40.5 +/- 9.0 min; P = 0.009). Resting Tc was lower in the AM trial and remained lower for the first 25 min of exercise (P exercise (P exercise capacity in the heat was significantly greater in the morning than the evening, possibly due to a lower initial Tc.

  1. Analytical evaluation of thermal conductance and heat capacities of one-dimensional material systems

    Energy Technology Data Exchange (ETDEWEB)

    Saygi, Salih [Department of Physics, Gaziosmanpasa University, Tokat, 60200 Turkey (Turkey)

    2014-02-15

    We theoretically predict some thermal properties versus temperature dependence of one dimensional (1D) material nanowire systems. A known method is used to provide an efficient and reliable analytical procedure for wide temperature range. Predicted formulas are expressed in terms of Bloch-Grüneisen functions and Debye functions. Computing results has proved that the expressions are in excellent agreement with the results reported in the literature even if it is in very low dimension limits of nanowire systems. Therefore the calculation method is a fully predictive approach to calculate thermal conductivity and heat capacities of nanowire material systems.

  2. 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.

  3. Hybrid Heat Pipes for High Heat Flux Applications Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The thermal transport requirements for future spacecraft missions continue to increase, approaching several kilowatts. At the same time the heat acquisition areas...

  4. Rapid, in Situ Synthesis of High Capacity Battery Anodes through High Temperature Radiation-Based Thermal Shock.

    Science.gov (United States)

    Chen, Yanan; Li, Yiju; Wang, Yanbin; Fu, Kun; Danner, Valencia A; Dai, Jiaqi; Lacey, Steven D; Yao, Yonggang; Hu, Liangbing

    2016-09-14

    High capacity battery electrodes require nanosized components to avoid pulverization associated with volume changes during the charge-discharge process. Additionally, these nanosized electrodes need an electronically conductive matrix to facilitate electron transport. Here, for the first time, we report a rapid thermal shock process using high-temperature radiative heating to fabricate a conductive reduced graphene oxide (RGO) composite with silicon nanoparticles. Silicon (Si) particles on the order of a few micrometers are initially embedded in the RGO host and in situ transformed into 10-15 nm nanoparticles in less than a minute through radiative heating. The as-prepared composites of ultrafine Si nanoparticles embedded in a RGO matrix show great performance as a Li-ion battery (LIB) anode. The in situ nanoparticle synthesis method can also be adopted for other high capacity battery anode materials including tin (Sn) and aluminum (Al). This method for synthesizing high capacity anodes in a RGO matrix can be envisioned for roll-to-roll nanomanufacturing due to the ease and scalability of this high-temperature radiative heating process.

  5. Carbohydrate ingestion and pre-cooling improves exercise capacity following soccer-specific intermittent exercise performed in the heat.

    Science.gov (United States)

    Clarke, N D; Maclaren, D P M; Reilly, T; Drust, B

    2011-07-01

    Ingestion of carbohydrate and reducing core body temperature pre-exercise, either separately or combined, may have ergogenic effects during prolonged intermittent exercise in hot conditions. The aim of this investigation was to examine the effect of carbohydrate ingestion and pre-cooling on the physiological responses to soccer-specific intermittent exercise and the impact on subsequent high-intensity exercise performance in the heat. Twelve male soccer players performed a soccer-specific intermittent protocol for 90 min in the heat (30.5°C and 42.2% r.h.) on four occasions. On two occasions, the participants underwent a pre-cooling manoeuvre. During these sessions either a carbohydrate-electrolyte solution (CHOc) or a placebo was consumed at (PLAc). During the remaining sessions either the carbohydrate-electrolyte solution (CHO) or placebo (PLA) was consumed. At 15-min intervals throughout the protocol participants performed a mental concentration test. Following the soccer-specific protocol participants performed a self-chosen pace test and a test of high-intensity exercise capacity. The period of pre-cooling significantly reduced core temperature, muscle temperature and thermal sensation (P carbohydrate during exercise enhances exercise capacity and helps maintain mental performance during intermittent exercise in hot conditions.

  6. High temperature absorption compression heat pump for industrial waste heat

    DEFF Research Database (Denmark)

    Reinholdt, Lars; Horntvedt, B.; Nordtvedt, S. R.

    2016-01-01

    , and they have proved themselves a very efficient and reliable technology for applications that have large temperature changes on the heat sink and/or heat source. The concept of Carnot and Lorenz efficiency and its use in the analysis of system integration is shown. A 1.25 MW system having a Carnot efficiency...

  7. High Capacity Cathode Materials for Next Generation Energy Storage

    Science.gov (United States)

    Papandrea, Benjamin John

    Energy storage devices are of increasing importance for applications in mobile electronics, hybrid electric vehicles, and can also play a critical role in renewable energy harvesting, conversion and storage. Since its commercial inception in the 1990's, the lithium-ion battery represents the dominant energy storage technology for mobile power supply today. However, the total capacity of lithium-ion batteries is largely limited by the theoretical capacities of the cathode materials such as LiCoO2 (272 mAh g-1), and LiFePO4 (170 mAh g-1), and cannot satisfy the increasing consumer demand, thus new cathode materials with higher capacities must be explored. Two of the most promising cathode materials with significantly larger theoretical capacities are sulfur (1675 mAh g-1) and air, specifically the oxygen (3840 mAh g-1). However, the usage of either of these cathodic materials is plagued with numerous issues that must be overcome before their commercialization. In the first part of my dissertation, we investigated the usage of a three-dimensional graphene membrane for a high energy density lithium-air (Li-Air) battery in ambient condition. One of the issues with Li-Air batteries is the many side reaction that can occur during discharge in ambient condition, especially with water vapor. Using a hydrophobic tortuous three-dimensional graphene membrane we are able to inhibit the diffusion of water vapor and create a lithium-air battery that cycles over 2000 times with a capacity limited at 140 mAh g-1, over 100 cycles with a capacity limited at 1425 mAh g-1, and over 20 cycles at the high capacity of 5700 mAh g-1. In the second part of my dissertation, we investigate the usage of a three-dimensional graphene aerogel to maximize the loading of sulfur to create a freestanding electrode with high capacity for a lithium-sulfur (Li-S) battery. We demonstrated that our three-dimensional graphene aerogel could sustain a loading of 95% by weight, and we achieved a capacity of

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

    Energy Technology Data Exchange (ETDEWEB)

    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 /sup 4/He adsorbed on metallic films. In contrast to measurements of /sup 4/He adsorbed on all other insulating substrates, we have shown that /sup 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, /sup 4/He adsorbed on sapphire and on Ag films and H/sub 2/ adsorbed on Ag films. The results are compared with appropriate theories. 68 refs., 19 figs.

  9. Influence of heat treatment on antioxidant capacity and (poly)phenolic compounds of selected vegetables.

    Science.gov (United States)

    Juániz, Isabel; Ludwig, Iziar A; Huarte, Estibaliz; Pereira-Caro, Gema; Moreno-Rojas, Jose Manuel; Cid, Concepción; De Peña, María-Paz

    2016-04-15

    The impact of cooking heat treatments (frying in olive oil, frying in sunflower oil and griddled) on the antioxidant capacity and (poly)phenolic compounds of onion, green pepper and cardoon, was evaluated. The main compounds were quercetin and isorhamnetin derivates in onion, quercetin and luteolin derivates in green pepper samples, and chlorogenic acids in cardoon. All heat treatments tended to increase the concentration of phenolic compounds in vegetables suggesting a thermal destruction of cell walls and sub cellular compartments during the cooking process that favor the release of these compounds. This increase, specially that observed for chlorogenic acids, was significantly correlated with an increase in the antioxidant capacity measured by DPPH (r=0.70). Griddled vegetables, because of the higher temperature applied during treatment in comparison with frying processes, showed the highest amounts of phenolic compounds with increments of 57.35%, 25.55% and 203.06% compared to raw onion, pepper and cardoon, respectively. Copyright © 2015 Elsevier Ltd. All rights reserved.

  10. High heat load test of molybdenum

    Energy Technology Data Exchange (ETDEWEB)

    Tanabe, T. (Faculty of Engineering, Osaka Univ., Suita (Japan)); Fujine, M.; Noguchi, H. (Daido Steel Co. Ltd., Nagoya (Japan)); Yagi, Y.; Hirano, Y.; Shimizu, H. (Electrotechnical Lab., Umezono, Tsukuba (Japan)); Akiba, M.; Araki, M. (Japan Atomic Energy Research Inst., Naka, Ibaraki (Japan)); Kubota, Y.; Miyahara, A. (National Inst. for Fusion Science, Nagoya (Japan))

    1993-03-01

    Three different types of molybdenum, powder metallurgical polycrystalline (PM-Mo), and as-forged polycrystalline and single crystalline of highly purified electron-beam-melted Mo (AFEB-Mo and SCEB-Mo), have been subjected to high heat load test with neutral beam injection (NBI) stands at Japan Atomic Energy Research Institute (JAERI) and National Institute for Fusion Science (NIFS). These materials have also been tested as a movable limiter in a reversed field pinch machine (RFP:TPE-1RM15) in Electrotechnical Laboratory (ETL). The results are summarized as follows. The SCEB-Mo shows the least damage with slight local melting after a very high heat load of 260 MW/m[sup 2] for 250 ms with NBI, while for the PM-Mo the whole irradiated area melt with many craters due to impurity gas evaporation under less heat load (200 ms). All movable limiter heads of the RFP are severely damaged with partial melting. The appearance of the SCEB-Mo limiter after melting is not good and shows the crystalline cleavage. However, SEM observation of the microstructure opposes the surface appearance. In the SCEB-Mo, appreciable recrystallization is not observed and hence no crack is seen to go into the bulk except the crystalline cleavage. In the PM-Mo, on the other hand, the resolidification to columnar grains as well as the recrystallization is apparent, and the cracks not only go along the columnar grains but also separate the recrystallized region from the matrix. In the AFEB-Mo, a slight grain growth occurs and several cracks enter deep along the grain boundaries. Thus the SCEB-Mo is a very nice plasma-facing material if used under the critical heat load for melting. (orig.).

  11. 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.

  12. 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

  13. DESIGN OF A COMPACT HEAT EXCHANGER FOR HEAT RECUPERATION FROM A HIGH TEMPERATURE ELECTROLYSIS SYSTEM

    Energy Technology Data Exchange (ETDEWEB)

    G. K. Housley; J.E. O' Brien; G.L. Hawkes

    2008-11-01

    Design details of a compact heat exchanger and supporting hardware for heat recuperation in a high-temperature electrolysis application are presented. The recuperative heat exchanger uses a vacuum-brazed plate-fin design and operates between 300 and 800°C. It includes corrugated inserts for enhancement of heat transfer coefficients and extended heat transfer surface area. Two recuperative heat exchangers are required per each four-stack electrolysis module. The heat exchangers are mated to a base manifold unit that distributes the inlet and outlet flows to and from the four electrolysis stacks. Results of heat exchanger design calculations and assembly details are also presented.

  14. Heat capacity peak at the quantum critical point of the transverse Ising magnet CoNb2O6.

    Science.gov (United States)

    Liang, Tian; Koohpayeh, S M; Krizan, J W; McQueen, T M; Cava, R J; Ong, N P

    2015-07-06

    The transverse Ising magnet Hamiltonian describing the Ising chain in a transverse magnetic field is the archetypal example of a system that undergoes a transition at a quantum critical point (QCP). The columbite CoNb2O6 is the closest realization of the transverse Ising magnet found to date. At low temperatures, neutron diffraction has observed a set of discrete collective spin modes near the QCP. Here, we ask if there are low-lying spin excitations distinct from these relatively high-energy modes. Using the heat capacity, we show that a significant band of gapless spin excitations exists. At the QCP, their spin entropy rises to a prominent peak that accounts for 30% of the total spin degrees of freedom. In a narrow field interval below the QCP, the gapless excitations display a fermion-like, temperature-linear heat capacity below 1 K. These novel gapless modes are the main spin excitations participating in, and affected by, the quantum transition.

  15. Calibration of a low temperature calorimeter and application in the determination of isobaric heat capacity of 2-propanol

    Energy Technology Data Exchange (ETDEWEB)

    Casas, L.M., E-mail: lmcasas@uvigo.es [Departamento de Fisica Aplicada, Facultade de Ciencias Experimentais, Universidade de Vigo, Lagoas Marcosende s/n, 36310 Vigo (Spain); Plantier, F. [Laboratoire de Thermodynamique et Energetique des Fluides Complexes - UMR 5150, Universite de Pau et des Pays de l' Adour, BP 1155, 64013 Pau (France); Pineiro, M.M.; Legido, J.L. [Departamento de Fisica Aplicada, Facultade de Ciencias Experimentais, Universidade de Vigo, Lagoas Marcosende s/n, 36310 Vigo (Spain); Bessieres, D. [Laboratoire de Thermodynamique et Energetique des Fluides Complexes - UMR 5150, Universite de Pau et des Pays de l' Adour, BP 1155, 64013 Pau (France)

    2010-08-10

    Nowadays, the experimental thermodynamic characterization of solvents in an extended range of temperatures and pressures is essential for the development of a wide variety of industrial applications (refrigeration, reactors, pumping, etc.). Moreover, accurate experimental data are also the key for the successful development and subsequent benchmarking of thermodynamic theoretical models. In the particular case of isobaric heat capacities, there are quite a lot of reported experimental high temperature data but, on the other hand, low temperature data are practically inexistent for most compounds. Bearing this limitation in mind, the present work is focused on the development of a new calibration methodology for calorimetric determination of isobaric heat capacities in liquid state at low temperatures. For this purpose, a Calvet calorimeter, SETARAM BT 2.15 has been used. By means of the calibration procedure explained below, this calorimeter allows to determine phase transitions and thermodynamic properties in a wide range of temperature (233.15-473.15 K) and pressure (0.1-100 MPa).

  16. 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

  17. High-capacity electrode materials for electrochemical energy ...

    Indian Academy of Sciences (India)

    2015-06-02

    Jun 2, 2015 ... This review summarizes the current state-of-the art electrode materials used for high-capacity lithium-ion-based batteries and their significant role towards revolutionizing the electrochemical energy storage landscape in the area of consumer electronics, transportation and grid storage application.

  18. Cycloaddition in peptides for high-capacity optical storage

    DEFF Research Database (Denmark)

    Lohse, Brian; Berg, Rolf Henrik; Hvilsted, Søren

    2006-01-01

    Photodimerization of chromophores attached to a short peptide chain is investigated for high-capacity optical digital storage with UV lasers. The length and rigidity of the peptide chain assure an optimal distance and orientation of the chromophores for effective photodimerization. Using a theory...

  19. Low temperature heating and high temperature cooling embedded water based surface heating and cooling systems

    CERN Document Server

    Babiak, Jan; Petras, Dusan

    2009-01-01

    This Guidebook describes the systems that use water as heat-carrier and when the heat exchange within the conditioned space is more than 50% radiant. Embedded systems insulated from the main building structure (floor, wall and ceiling) are used in all types of buildings and work with heat carriers at low temperatures for heating and relatively high temperature for cooling.

  20. 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.

  1. CSTI high capacity power. [Civil Space Technology Initiative

    Science.gov (United States)

    Winter, Jerry M.

    1989-01-01

    In FY-88, the Advanced Technology Program was incorporated into NASA's 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 Converrsion 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.

  2. 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.

  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. Temperature Dependence of the Molar Heat Capacity for Ferromagnets Within the Mean Field Theory

    Science.gov (United States)

    Fernández Rodríguez, J.; Blanco, J. A.

    2005-01-01

    We describe, using the Mean Field Theory, a detailed analysis of the magnetic contribution to the molar heat capacity Cmag for ferromagnetic systems. This calculation is designed to be used as a teaching homework problem for physics undergraduates. The description emphasises that Cmag at the transition temperature TC is characterised by the existence of a simple jump discontinuity anomaly, but when the temperature is lowered down to 0 K the shape of Cmag depends strongly on the magnitude of the spin S. In fact, the appearance of a shoulder in Cmag for S > 3/2 is expected. The origin of this shoulder could be understood as a Schottky-like anomaly in the ordered state. These physical results are in good agreement with those from real systems, and give the student a valuable insight into the behaviour of the thermodynamical response of a ferromagneticmaterial.

  5. Avian thermoregulation in the heat: evaporative cooling capacity in an archetypal desert specialist, Burchell's sandgrouse (Pterocles burchelli).

    Science.gov (United States)

    McKechnie, Andrew E; Smit, Ben; Whitfield, Maxine C; Noakes, Matthew J; Talbot, William A; Garcia, Mateo; Gerson, Alexander R; Wolf, Blair O

    2016-07-15

    Sandgrouse (Pterocliformes) are quintessential examples of avian adaptation to desert environments, but relatively little is known about the limits to their heat tolerance and evaporative cooling capacity. We predicted that evaporative cooling in Burchell's sandgrouse (Pterocles burchelli) is highly efficient and provides the basis for tolerance of very high air temperature (Ta). We measured body temperature (Tb), resting metabolic rate (RMR) and evaporative water loss (EWL) at Ta between 25°C and ∼58°C in birds exposed to successive increments in Ta Normothermic Tb averaged 39.0°C, lower than typical avian values. At Ta>34.5°C, Tb increased linearly to a maximum of 43.6°C at Ta=56°C. The upper critical limit of thermoneutrality (Tuc) was Ta=43.8°C, closely coinciding with the onset of panting and gular flutter. Above the Tuc, RMR increased 2.5-fold to 2.89 W at Ta=56°C, a fractional increase far exceeding that of many other species under comparable conditions. Rates of EWL increased rapidly at Ta>42.9°C to 7.84±0.90 g h(-1) at Ta=56°C, an 11-fold increase above minimal levels. Maximum evaporative cooling efficiency (ratio of evaporative heat loss to metabolic heat production) was 2.03, but could be as high as 2.70 if our assumption that the birds were metabolising lipids is incorrect. Thermoregulation at very high Ta in P. burchelli was characterised by large increases in RMR and EWL, and is much less efficient than in taxa such as columbids and caprimulgids. © 2016. Published by The Company of Biologists Ltd.

  6. Measurement uncertainties when determining heat rate, isentropic efficiency and swallowing capacity

    Energy Technology Data Exchange (ETDEWEB)

    Snygg, U.

    1996-05-01

    The objective of the project was to determine the uncertainties when calculating heat rate, isentropic efficiencies and swallowing capacities of power plants. Normally when a power plant is constructed, the supplier also guarantee some performance values, e.g. heat rate. When the plant is built and running under normal conditions, an evaluation is done and the guarantee values are checked. Different measured parameters influence the calculated value differently, and therefore a sensitivity factor can be defined as the sensitivity of a calculated value when the measured value is changing. The product of this factor and the uncertainty of the measured parameter gives an error of the calculated value. For every measured parameter, the above given factor has to be determined and then the root square sum gives the overall uncertainty of the calculated parameter. To receive acceptable data during the evaluation of the plant, a test code is to be followed. The test code also gives guidelines how big the errors of the measurements are. In this study, ASME PTC6 and DIN 1943 were used. The results show that not only the test code was of vital importance, but also the distribution of the power output of the HP-IP turbines contra LP turbines. A higher inlet pressure of the LP turbine gives a smaller uncertainty of the isentropic efficiency. An increase from 6 to 13 bar will lower the uncertainty 1.5 times. 10 refs, 24 figs, 23 tabs, 5 appendixes

  7. Comparison of the high temperature heat flux sensor to traditional heat flux gages under high heat flux conditions.

    Energy Technology Data Exchange (ETDEWEB)

    Blanchat, Thomas K.; Hanks, Charles R.

    2013-04-01

    Four types of heat flux gages (Gardon, Schmidt-Boelter, Directional Flame Temperature, and High Temperature Heat Flux Sensor) were assessed and compared under flux conditions ranging between 100-1000 kW/m2, such as those seen in hydrocarbon fire or propellant fire conditions. Short duration step and pulse boundary conditions were imposed using a six-panel cylindrical array of high-temperature tungsten lamps. Overall, agreement between all gages was acceptable for the pulse tests and also for the step tests. However, repeated tests with the HTHFS with relatively long durations at temperatures approaching 1000ÀC showed a substantial decrease (10-25%) in heat flux subsequent to the initial test, likely due to the mounting technique. New HTHFS gages have been ordered to allow additional tests to determine the cause of the flux reduction.

  8. Heat capacity and density of solutions of calcium and cadmium nitrates in N-methylpyrrolidone at 298.15 K

    Science.gov (United States)

    Novikov, A. N.; Rassokhina, L. Yu.

    2013-08-01

    The heat capacity and density of solutions of calcium and cadmium nitrates in N-methylpyrrolidone (MP) at 298.15 K are studied by calorimetry and densimetry. The obtained data are discussed in relation to certain features of solvation and complex formation in solutions of these salts. The standard partial molar heat capacities and volumes (overline {C_{p^2 }^0 } and overline {V_2^0 }) of the electrolytes in MP are calculated. The standard heat capacities overline {C_{p^i }^0 } and volumes overline {V_i^0 } of Ca2+ and Cd2+ ions in MP at 298.15 K were determined, along with the contribution from specific interactions to the values of overline {C_{p^i }^0 } and overline {V_i^0 } of Cd2+ ions in MP solution.

  9. Heat capacity and density of solutions of lithium and sodium nitrates in N-methylpyrrolidone at 298.15 K

    Science.gov (United States)

    Novikov, A. N.

    2013-09-01

    The heat capacity and density of solutions of lithium and sodium nitrates in N-methylpyrrolidone (MP) at 298.15 K are studied by calorimetry and densimetry. The standard partial molar heat capacities and volumes ( C¯ p,2° and V¯ 2°) of LiNO3 and NaNO3 in MP are calculated. The standard heat capacities C¯ p,i ° and volumes V¯ i ° of Li+ and Na+ ions in MP at 298.15 K are determined on the basis of a proposed scale of ionic contributions of C¯ p,2° and V¯ 2° values. The obtained data are discussed in relation to certain features of solvation in solutions of the investigated salts.

  10. 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...

  11. 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

  12. 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.

  13. Negative heat capacity in the critical region of nuclear fragmentation: an experimental evidence of the liquid-gas phase transition

    Science.gov (United States)

    D'Agostino, M.; Gulminelli, F.; Chomaz, P.; Bruno, M.; Cannata, F.; Bougault, R.; Gramegna, F.; Iori, I.; Le Neindre, N.; Margagliotti, G. V.; Moroni, A.; Vannini, G.

    2000-02-01

    An experimental indication of negative heat capacity in excited nuclear systems is inferred from the event by event study of energy fluctuations in Au quasi-projectile sources formed in Au+Au collisions at 35 A.MeV. Equilibrated events are selected and the excited source configuration is reconstructed through a calorimetric analysis of its de-excitation products. Fragment partitions show signs of a critical behavior at about 4.5 A.MeV excitation energy. Around this value the heat capacity shows a negative branch providing a direct evidence of a first order liquid gas phase transition.

  14. Heat capacity and thermodynamic functions of thulium orthophosphate TmPO4 in the range of 10-1350 K

    Science.gov (United States)

    Ryumin, M. A.; Gurevich, V. M.; Khoroshilov, A. V.; Tyurin, A. V.; Gavrichev, K. S.

    2017-12-01

    The heat capacity of TmPO4 in temperature ranges of 9.11-346.05 and 304.6-1344.6 K is measured via adiabatic and differential scanning calorimetry, respectively. The measurement data are used to calculate the temperature dependences of the heat capacity, entropy, change in enthalpy, and reduced Gibbs energy of TmPO4 in the range of 10-1344 K. The Gibbs energy of formation of thulium orthophosphate from elements Δf G 0(298.15 K) is determined.

  15. High-temperature self-circulating thermoacoustic heat exchanger

    Science.gov (United States)

    Backhaus, S.; Swift, G. W.; Reid, R. S.

    2005-07-01

    Thermoacoustic and Stirling engines and refrigerators use heat exchangers to transfer heat between the oscillating flow of their thermodynamic working fluids and external heat sources and sinks. An acoustically driven heat-exchange loop uses an engine's own pressure oscillations to steadily circulate its own thermodynamic working fluid through a physically remote high-temperature heat source without using moving parts, allowing for a significant reduction in the cost and complexity of thermoacoustic and Stirling heat exchangers. The simplicity and flexibility of such heat-exchanger loops will allow thermoacoustic and Stirling machines to access diverse heat sources and sinks. Measurements of the temperatures at the interface between such a heat-exchange loop and the hot end of a thermoacoustic-Stirling engine are presented. When the steady flow is too small to flush out the mixing chamber in one acoustic cycle, the heat transfer to the regenerator is excellent, with important implications for practical use.

  16. 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 [University of Central Florida, Florida Solar Energy Center; Withers, Chuck [University of Central Florida, Florida Solar Energy Center; McIlvaine, Janet [University of Central Florida, Florida Solar Energy Center; Chasar, Dave [University of Central Florida, Florida Solar Energy Center; Beal, David [University of Central Florida, 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.

  17. Age-related differences in heat loss capacity occur under both dry and humid heat stress conditions.

    Science.gov (United States)

    Larose, Joanie; Boulay, Pierre; Wright-Beatty, Heather E; Sigal, Ronald J; Hardcastle, Stephen; Kenny, Glen P

    2014-07-01

    This study examined the progression of impairments in heat dissipation as a function of age and environmental conditions. Sixty men (n = 12 per group; 20-30, 40-44, 45-49, 50-54, and 55-70 yr) performed four intermittent exercise/recovery cycles for a duration of 2 h in dry (35°C, 20% relative humidity) and humid (35°C, 60% relative humidity) conditions. Evaporative heat loss and metabolic heat production were measured by direct and indirect calorimetry, respectively. Body heat storage was measured as the temporal summation of heat production and heat loss during the sessions. Evaporative heat loss was reduced during exercise in the humid vs. dry condition in age groups 20-30 (-17%), 40-44 (-18%), 45-49 (-21%), 50-54 (-25%), and 55-70 yr (-20%). HE fell short of being significantly different between groups in the dry condition, but was greater in age group 20-30 yr (279 ± 10 W) compared with age groups 45-49 (248 ± 8 W), 50-54 (242 ± 6 W), and 55-70 yr (240 ± 7 W) in the humid condition. As a result of a reduced rate of heat dissipation predominantly during exercise, age groups 40-70 yr stored between 60-85 and 13-38% more heat than age group 20-30 yr in the dry and humid conditions, respectively. These age-related differences in heat dissipation and heat storage were not paralleled by significant differences in local sweating and skin blood flow, or by differences in core temperature between groups. From a whole body perspective, combined heat and humidity impeded heat dissipation to a similar extent across age groups, but, more importantly, intermittent exercise in dry and humid heat stress conditions created a greater thermoregulatory challenge for middle-aged and older adults. Copyright © 2014 the American Physiological Society.

  18. 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.

  19. 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.

  20. 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.

  1. 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).

  2. 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

  3. 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

  4. 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

  5. High resolution numerical modelling of high temperature heat storage in geological media

    Science.gov (United States)

    Boockmeyer, Anke; Bauer, Sebastian

    2014-05-01

    Increasing use of energy stemming from renewable sources, such as wind or solar power plants, requires development of new and improvement of existing energy storage options on different time scales. One potential storage option is high temperature heat storage with temperatures of up to 100°C in the geological subsurface using borehole heat exchanger (BHE). Numerical scenario simulations are performed to assess feasibility and storage capacity and, furthermore, to predict the effects induced. To allow for accurate and reliable results, the BHE must be represented correctly and realistic in the numerical model. Therefore, a detailed model of a single BHE and the surrounding aquifer, accounting for the full geometry and component parametrisation (circulating working fluid, pipe and grout), is set up. This model setup is used to simulate an experimental data set from a laboratory sandbox by Beier et al. (2011), containing an 18 m long single U-tube BHE centered horizontally along it. Temperature curves observed in different radial distances as well as at the pipe outflow can be matched well with the model setup used, which is thus verified. Potential geological formations for high temperature heat storage are located in greater depths below fresh water aquifers that are used for drinking water. Therefore, the above model is adapted to represent a 100 m long vertical double U-tube BHE placed in an average depth of 500 m. The processes of heat transport and groundwater flow are coupled by water density and viscosity, which both depend on pressure and temperature. A sensitivity study is done to quantify the effects of the thermal parameters of grout and aquifer on the amount of heat stored and the temperature distribution in the aquifer. It was found that the amount of heat stored through the BHE is most sensitive to the heat conductivity of the aquifer. Increasing the aquifer heat conductivity by 50 % increases the amount of heat stored in the numerical model by 30

  6. Determination of heat capacity of ionic liquid based nanofluids using group method of data handling technique

    Science.gov (United States)

    Sadi, Maryam

    2017-07-01

    In this study a group method of data handling model has been successfully developed to predict heat capacity of ionic liquid based nanofluids by considering reduced temperature, acentric factor and molecular weight of ionic liquids, and nanoparticle concentration as input parameters. In order to accomplish modeling, 528 experimental data points extracted from the literature have been divided into training and testing subsets. The training set has been used to predict model coefficients and the testing set has been applied for model validation. The ability and accuracy of developed model, has been evaluated by comparison of model predictions with experimental values using different statistical parameters such as coefficient of determination, mean square error and mean absolute percentage error. The mean absolute percentage error of developed model for training and testing sets are 1.38% and 1.66%, respectively, which indicate excellent agreement between model predictions and experimental data. Also, the results estimated by the developed GMDH model exhibit a higher accuracy when compared to the available theoretical correlations.

  7. Heat capacity changes associated with guanine quadruplex formation: an isothermal titration calorimetry study.

    Science.gov (United States)

    Majhi, Pinaki R; Qi, Jianying; Tang, Chung-Fei; Shafer, Richard H

    2008-04-01

    This study addresses the temperature dependence of the enthalpy of formation for several unimolecular quadruplexes in the presence of excess monovalent salt. We examined a series of biologically significant guanine-rich DNA sequences: thrombin binding aptamer (TBA) (d(G(2)T(2)G(2)TGTG(2)T(2)G(2)), PS2.M, a catalytically active aptamer (d(GTG(3)TAG(3)CG(3)T(2)G(2))), and the human telomere repeat (HT) (d(AG(3)(T(2)AG(3))(3))). Using CD spectra and UV melting, we confirmed the presence of quadruplex structures and established the temperature range in which quadruplex conformation is stable. We then performed ITC experiments, adding DNA to a solution containing excess NaCl or KCl. In this approach, only several additions are made, and only the enthalpy of quadruplex formation is measured. This measurement was repeated at different temperatures to determine the temperature dependence of the enthalpy change accompanying quadruplex formation. To control for the effect of nonspecific salt interactions during DNA folding, we repeated the experiment by replacing the quadruplex-forming sequences with a similar but nonfolding sequence. Dilution enthalpies were also subtracted to obtain the final enthalpy value involving only the quadruplex folding process. For all sequences studied, quadruplex formation was exothermic but with an increasing magnitude with increasing temperature. These results are discussed in terms of the change in heat capacity associated with quadruplex formation.

  8. Simultaneous measurement of thermal conductivity and heat capacity by flash thermal imaging methods

    Science.gov (United States)

    Tao, N.; Li, X. L.; Sun, J. G.

    2017-06-01

    Thermal properties are important for material applications involved with temperature. Although many measurement methods are available, they may not be convenient to use or have not been demonstrated suitable for testing of a wide range of materials. To address this issue, we developed a new method for the nondestructive measurement of the thermal effusivity of bulk materials with uniform property. This method is based on the pulsed thermal imaging-multilayer analysis (PTI-MLA) method that has been commonly used for testing of coating materials. Because the test sample for PTI-MLA has to be in a two-layer configuration, we have found a commonly used commercial tape to construct such test samples with the tape as the first-layer material and the bulk material as the substrate. This method was evaluated for testing of six selected solid materials with a wide range of thermal properties covering most engineering materials. To determine both thermal conductivity and heat capacity, we also measured the thermal diffusivity of these six materials by the well-established flash method using the same experimental instruments with a different system setup. This paper provides a description of these methods, presents detailed experimental tests and data analyses, and discusses measurement results and their comparison with literature values.

  9. Low temperature resonances in the fermion heat capacity of finite systems

    Energy Technology Data Exchange (ETDEWEB)

    Kuzmenko, N K [V.G. Khlopin Radium Institute, 194021 St.-Petersburg (Russian Federation); Mikhajlov, V M [Institute of Physics St.-Petersburg State University 198904 (Russian Federation)], E-mail: kuzmenko@NK9433.spb.edu

    2009-02-01

    Temperature variations of the heat capacity (C) are studied in a low temperature regime T < {epsilon}{sub f}/N ({epsilon}{sub f} is the Fermi energy) for 2D-, and 3D-systems with N{approx} 10{sup 2} to 10{sup 4} treated as a canonical ensemble of N-noninteracting fermions. The analysis of C is performed by introducing a function {rho}({epsilon}), the spectral distribution of C that gives the contribution of each single-particle state to C. The function {rho}({epsilon}) has two peaks divided by the energy interval {delta} {epsilon} {approx} (2 to 5) T. If at some temperature T{sub res} there takes place a resonance i.e. the positions of these peaks coincide with energies of two levels nearest to {epsilon}{sub F} then C vs T shows a local maximum i.e. T{sub res} is determined by single-particle level spacings near the Fermi level.

  10. Floor heating of high-rise buildings

    Energy Technology Data Exchange (ETDEWEB)

    Korff, H.K.

    1979-01-01

    When planning a large housing estate near Aschaffenburg in the years from 1962 to 1965, the decision was made to use electric floor heating fed mainly by off-peak electricity. In order to keep the cost of heating at an acceptable level and for better use of the storage effect, a type of thermal insulation was installed which was far in advance of the methods used at the time. The heat transmission coefficient of the external walls was later on found to be 0.88 W/m/sup 2/K. This value fully meets the requirements as specified in the thermal insulation ordinance which came into force in 1977. A cost analysis has shown that the heating costs are not higher than in similar buildings equipped with conventional heating systems.

  11. High Efficiency R-744 Commercial Heat Pump Water Heaters

    Energy Technology Data Exchange (ETDEWEB)

    Elbel, Dr. Stefan W.; Petersen, Michael

    2013-04-25

    The project investigated the development and improvement process of a R744 (CO2) commercial heat pump water heater (HPWH) package of approximately 35 kW. The improvement process covered all main components of the system. More specific the heat exchangers (Internal heat exchanger, Evaporator, Gas cooler) as well as the expansion device and the compressor were investigated. In addition, a comparison to a commercially available baseline R134a unit of the same capacity and footprint was made in order to compare performance as well as package size reduction potential.

  12. 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.

  13. 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.

  14. Rapid heating of matter using high power lasers

    Energy Technology Data Exchange (ETDEWEB)

    Bang, Woosuk [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-04-08

    This slide presentation describes motivation (uniform and rapid heating of a target, opportunity to study warm dense matter, study of nuclear fusion reactions), rapid heating of matter with intense laser-driven ion beams, visualization of the expanding warm dense gold and diamond, and nuclear fusion experiments using high power lasers (direct heating of deuterium spheres (radius ~ 10nm) with an intense laser pulse.

  15. High-capacity quantum Fibonacci coding for key distribution

    Science.gov (United States)

    Simon, David S.; Lawrence, Nate; Trevino, Jacob; Dal Negro, Luca; Sergienko, Alexander V.

    2013-03-01

    Quantum cryptography and quantum key distribution (QKD) have been the most successful applications of quantum information processing, highlighting the unique capability of quantum mechanics, through the no-cloning theorem, to securely share encryption keys between two parties. Here, we present an approach to high-capacity, high-efficiency QKD by exploiting cross-disciplinary ideas from quantum information theory and the theory of light scattering of aperiodic photonic media. We propose a unique type of entangled-photon source, as well as a physical mechanism for efficiently sharing keys. The key-sharing protocol combines entanglement with the mathematical properties of a recursive sequence to allow a realization of the physical conditions necessary for implementation of the no-cloning principle for QKD, while the source produces entangled photons whose orbital angular momenta (OAM) are in a superposition of Fibonacci numbers. The source is used to implement a particular physical realization of the protocol by randomly encoding the Fibonacci sequence onto entangled OAM states, allowing secure generation of long keys from few photons. Unlike in polarization-based protocols, reference frame alignment is unnecessary, while the required experimental setup is simpler than other OAM-based protocols capable of achieving the same capacity and its complexity grows less rapidly with increasing range of OAM used.

  16. Application of customized absorption heat pumps with heating capacities above 500 kW: Project: VIVO, Warngau (near Munich)

    OpenAIRE

    Zachmeier, Peter; Radspieler, Michael; Schweigler, Christian

    2013-01-01

    Part of: Thermally driven heat pumps for heating and cooling. – Ed.: Annett Kühn – Berlin: Universitätsverlag der TU Berlin, 2013 ISBN 978-3-7983-2686-6 (print) ISBN 978-3-7983-2596-8 (online) urn:nbn:de:kobv:83-opus4-39458 [http://nbn-resolving.de/urn:nbn:de:kobv:83-opus4-39458] In 2005 a gas fired single effect absorption heat pump was installed at the area of VIVO GmbH, who runs a local civic waste collection point. Besides other recyclable materials, biodegra...

  17. High Efficiency Microchannel Diamond Heat Sinks Project

    Data.gov (United States)

    National Aeronautics and Space Administration — While absolute power levels in microelectronic devices are relatively modest (a few tens to a few hundred watts), heat fluxes can be significant (~50 W/cm2 in...

  18. Measuring Specific Heats at High Temperatures

    Science.gov (United States)

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

    1987-01-01

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

  19. Mesoporous Silicon-Based Anodes for High Capacity, High Performance Li-ion Batteries Project

    Data.gov (United States)

    National Aeronautics and Space Administration — A new high capacity anode composite based on mesoporous silicon is proposed. By virtue of a structure that resembles a pseudo one-dimensional phase, the active anode...

  20. Capacity analysis for high-speed terahertz wireless communications

    DEFF Research Database (Denmark)

    Dogadaev, Anton Konstantinovich; Lavrinenko, Andrei; Tafur Monroy, Idelfonso

    2012-01-01

    We report on the analytical capacity analysis of terahertz wireless communications supporting 275–325 GHz frequency band. Our goal in this paper is to provide design guidelines for close proximity links with transmission capacity beyond 100 Gbit/s.......We report on the analytical capacity analysis of terahertz wireless communications supporting 275–325 GHz frequency band. Our goal in this paper is to provide design guidelines for close proximity links with transmission capacity beyond 100 Gbit/s....

  1. Industrial heat pumps for high temperature process applications

    DEFF Research Database (Denmark)

    Jensen, Jonas Kjær

    Industrial processes often consume large quantities of heat, while of-ten dissipating large quantities of waste heat to the ambient. The main energy source for industrial heat supply is fossil fuels, either oil or nat-ural gas. Thus, the heat consumption of industrial processes often entail large...... with the absorber. It is found that the cost of most components are evenly distributed between operational and capital investment cost. The highest rate of avoidable environmental impact stems from the compressor. It is shown that the environmental impact of construction, transportation and disposal was negligible...... CO2 emissions as well as emission of other harmful pollutants. As heat pumps can upgrade low temperature waste heat to a high temperature heat supply using only a fraction of primary energy, heat pumps may be applied to improve the energy efficiency of industrial processes. Further, Replacing oil...

  2. 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.

  3. 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.

  4. 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

  5. An automated flow calorimeter for the determination of liquid and vapor isobaric heat capacities: Test results for water and n -pentane

    Energy Technology Data Exchange (ETDEWEB)

    Sandarusi, J.A. (National Institute of Science and Technology, Thermophysics Division, Boulder, Colorado 80303 (United States)); Mulia, K.; Yesavage, V.F. (Colorado School of Mines, Chemical Engineering Department, Golden, Colorado 80401 (United States))

    1992-02-01

    An automated flow calorimeter has been developed for the measurement of highly accurate isobaric heat capacities and enthalpies of fluids at elevated temperatures and pressures. The instrument was successfully tested over the range 300--600 K and 0--12 MPa and is readily extensible to 700 K and 30 MPa. The flow calorimeter relied on an adiabatic design with a two-chambered cell design incorporating several concentric shells of active and passive shields designed to minimize heat losses, facilitate easy component replacement, and eliminate any external temperature regulation baths. A pair of miniature standard platinum resistance thermometers were built to determine the differential calorimeter temperatures. A precision metering pump eliminated the need for direct mass flow-rate determinations while a complete automation system supplied all of the required data acquisition, monitoring, and control (except for pressure) resources necessary to operate the calorimeter and make measurements from a single personal computer. Measurements of isobaric heat capacities were performed on water (liq.) and {ital n}-pentane (liq. and vap.) to test the new calorimeter. These experiments compared well with the published values, indicating an overall measurement precision of 0.1% and uncertainty in the range of 0.2%--0.3%. The total calorimeter heat leak was small affecting the experimental uncertainty as much as the combined mass flow-rate and calorimeter temperature difference errors.

  6. [High intellectual capacity, problem-solving and creativity].

    Science.gov (United States)

    Sastre-Riba, Sylvia; Pascual-Sufrate, M Teresa

    2013-02-22

    The aim of the study is focused on the characteristics and components of creativity as a multidimensional construct in the context of intelligence, divergent thinking and problem solving, and their incorporation into the definition and explanation of intellectual functioning of giftedness and talent. It shows the progress of the investigation from the initial postulates of Guilford about the nature and cognitive processes involved in the creative act, its features and components, development and differential expression in the high intellectual ability, and the neurological correlates neuropsychological research is beginning to show. We present the results obtained with 41 participants with high intellectual capacity profiles of giftedness or talent of 6 to 14 years. We measure their cognitive skills through BADyG or DAT tests, and creative skills by the Torrance Test of Creative Thinking (TTCT), in two measuring points. Analyses show comparatively among high ability profiles: 1) the creative measurement stability between the two time points, 2) statistically significant differences between the creative components of fluency, flexibility and originality, related to the profiles of giftedness or talent (convergent or divergent), 3) the statistically significant changes among the scores of the creative components, at all ages studied.

  7. Improving reversible capacities of high surface lithium insertion materials – the case of amorphous TiO2

    Directory of Open Access Journals (Sweden)

    Swapna eGanapathy

    2014-11-01

    Full Text Available Chemisorbed water and solvent molecules and their reactivity with components from the electrolyte in high-surface nanostructured electrodes remains a contributing factor towards 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 TiO2 by the choice of preparation solvent, control of annealing temperature and the presence of surface functional groups. Careful heating of the amorphous TiO2 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 TiO2 when prepared in ethanol and heated under vacuum showed an even better capacity retention of 240 mAh/g. From FTIR 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 (SEI. The present research provides a facile strategy to improve the capacity retention of nanostructured electrode materials.

  8. 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

  9. 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...... Tbit/s data packets, and time lens based serial-to-parallel converter is employed to demultiplex each high-capacity packet into lower bit rate tributaries. A novel optical label scheme is suggested and experimentally demonstrated, where the label information is inserted in-band in the broad signal...... from 640 Gbit/s variable length data packets. Finally, three optical switching scenarios of high-capacity data packets, including a record-high 1×2 optical packet switching of 1.28 Tbit/s serial packets, are experimentally demonstrated using electro-optic based LiNbO3 switches....

  10. Thermal expansion and the heat capacity of nanocrystalline and coarse-crystalline silver sulfide Ag2S

    Science.gov (United States)

    Sadovnikov, S. I.; Gusev, A. I.

    2017-09-01

    The thermal expansion and the heat capacity of coarse-crystalline and nanocrystalline silver sulfide Ag2S were studied by dilatometry and differential scanning calorimentry for the first time in the temperature range 290-970 K. It is found that the thermal expansion coefficient and the heat capacity of nanocrystalline silver sulfide in this temperature range are higher than those in the case of the coarse-crystalline sulfide. It is revealed that the transformation of α-Ag2S acanthite to β-Ag2S argentite and β-Ag2S argentite to γ-Ag2S phase are the first-order phase transitions; the temperatures and the enthalpies of these transformations have been determined.

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

    Science.gov (United States)

    Chegel, Raad

    2017-04-01

    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-, AB1- and AB2- 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.

  12. Calculation of thermal conductivity, thermal diffusivity and specific heat capacity of sedimentary rocks using petrophysical well logs

    DEFF Research Database (Denmark)

    Fuchs, Sven; Balling, Niels; Förster, Andrea

    2015-01-01

    In this study, equations are developed that predict for synthetic sedimentary rocks (clastics, carbonates and evapourates) thermal properties comprising thermal conductivity, specific heat capacity and thermal diffusivity. The rock groups are composed of mineral assemblages with variable contents...... of each property vary depending on the selected well-log combination. Best prediction is in the range of 2–8 per cent for the specific heat capacity, of 5–10 per cent for the thermal conductivity, and of 8–15 for the thermal diffusivity, respectively. Well-log derived thermal conductivity is validated...... by laboratory data measured on cores from deep boreholes of the Danish Basin, the North German Basin, and the Molasse Basin. Additional validation of thermal conductivity was performed by comparing predicted and measured temperature logs. The maximum deviation between these logs is conductivity...

  13. 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.

  14. Evaluation of injection methods for fast, high peak capacity separations with low thermal mass gas chromatography.

    Science.gov (United States)

    Fitz, Brian D; Mannion, Brandyn C; To, Khang; Hoac, Trinh; Synovec, Robert E

    2015-05-01

    Low thermal mass gas chromatography (LTM-GC) was evaluated for rapid, high peak capacity separations with three injection methods: liquid, headspace solid phase micro-extraction (HS-SPME), and direct vapor. An Agilent LTM equipped with a short microbore capillary column was operated at a column heating rate of 250 °C/min to produce a 60s separation. Two sets of experiments were conducted in parallel to characterize the instrumental platform. First, the three injection methods were performed in conjunction with in-house built high-speed cryo-focusing injection (HSCFI) to cryogenically trap and re-inject the analytes onto the LTM-GC column in a narrower band. Next, the three injection methods were performed natively with LTM-GC. Using HSCFI, the peak capacity of a separation of 50 nl of a 73 component liquid test mixture was 270, which was 23% higher than without HSCFI. Similar peak capacity gains were obtained when using the HSCFI with HS-SPME (25%), and even greater with vapor injection (56%). For the 100 μl vapor sample injected without HSCFI, the preconcentration factor, defined as the ratio of the maximum concentration of the detected analyte peak relative to the analyte concentration injected with the syringe, was determined to be 11 for the earliest eluting peak (most volatile analyte). In contrast, the preconcentration factor for the earliest eluting peak using HSCFI was 103. Therefore, LTM-GC is demonstrated to natively provide in situ analyte trapping, although not to as great an extent as with HSCFI. We also report the use of LTM-GC applied with time-of-flight mass spectrometry (TOFMS) detection for rapid, high peak capacity separations from SPME sampled banana peel headspace. Copyright © 2015 Elsevier B.V. All rights reserved.

  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. 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

    Energy Technology Data Exchange (ETDEWEB)

    Bharathan, D.; Nix, G.

    2001-08-06

    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.

  17. Laser Measurement of the Speed of Sound in Gases: A Novel Approach to Determining Heat Capacity Ratios and Gas Composition

    Science.gov (United States)

    Baum, J. Clayton; Compton, R. N.; Feigerle, Charles S.

    2008-01-01

    The speed of sound is measured in several gases using a pulsed laser to create a micro-spark on a carbon rod and a microphone connected to a digital oscilloscope to measure the time-of-flight of the resulting shockwave over a known distance. These data are used to calculate the heat capacity ratios (C[subscript p]/C[subscript V]) of the gases and…

  18. Magneto-heat capacity study on Kondo lattice system Ce(Ni1−xCux ...

    Indian Academy of Sciences (India)

    Abstract. Heat capacity studies on the Kondo lattice system Ce(Ni1−xCux)2Al3, in the presence of magnetic fields, were reported for x = 0.0−0.4. The physical properties of the intermediate compositions like x = 0.3 and 0.4 were known for their enhanced thermoelectric power and hence have been analysed with an extra ...

  19. Numerical study of the short pre-arcing time in high breaking capacity fuses via an enthalpy formulation

    Energy Technology Data Exchange (ETDEWEB)

    Rochette, David [Laboratoire Arc Electrique et Plasmas thermiques, CNRS UMR 6069, Universite Blaise Pascal-IUT de Montlucon, Avenue Aristide Briand, BP 2235, 03101 Montlucon Cedex (France); Touzani, Rachid [Laboratoire de Mathematiques, CNRS UMR 6620, Universite Blaise Pascal (Clermont-Ferrand II), Campus Universitaire des Cezeaux, 63177 Aubiere Cedex (France); Bussiere, William [Laboratoire Arc Electrique et Plasmas thermiques, CNRS UMR 6069, Universite Blaise Pascal-IUT de Montlucon, Avenue Aristide Briand, BP 2235, 03101 Montlucon Cedex (France)

    2007-08-07

    In order to study the short pre-arcing time in high breaking capacity (HBC) fuses, we use a mathematical model including the phase change of the fuse-element heating coupled with the Laplace equation for the potential and Ohm's law. The thermal model is based on the enthalpy formulation of the heat equation with a source term representing the Joule heating. For the time range considered (up to 10 ms), we assume no heat transfer between the fuse-element and the surrounding sand. To solve numerically the governing equations, we employ a semi-implicit scheme for time integration and a finite element method for space discretization. Using electrical and thermal properties of the silver fuse-element, we present pre-arcing characteristics (temperature, current density, potential) for a fuse-element used in industrial protection circuits.

  20. Heat Pipe Embedded AlSiC Plates for High Conductivity - Low CTE Heat Spreaders

    Energy Technology Data Exchange (ETDEWEB)

    Johnson, Matthew (DOE/NNSA Kansas City Plant (United States)); Weyant, J.; Garner, S. (Advanced Cooling Technologies, Inc. (Lancaster, PA (United States)); Occhionero, M. (CPS Technologies Corporation, Norton, MA (United States))

    2010-01-07

    Heat pipe embedded aluminum silicon carbide (AlSiC) plates are innovative heat spreaders that provide high thermal conductivity and low coefficient of thermal expansion (CTE). Since heat pipes are two phase devices, they demonstrate effective thermal conductivities ranging between 50,000 and 200,000 W/m-K, depending on the heat pipe length. Installing heat pipes into an AlSiC plate dramatically increases the plate’s effective thermal conductivity. AlSiC plates alone have a thermal conductivity of roughly 200 W/m-K and a CTE ranging from 7-12 ppm/ deg C, similar to that of silicon. An equivalent sized heat pipe embedded AlSiC plate has effective thermal conductivity ranging from 400 to 500 W/m-K and retains the CTE of AlSiC.

  1. 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.

  2. Heat capacity, lattice dynamics, and thermodynamic stability of the negative thermal expansion material HfMo2O8

    Science.gov (United States)

    Kennedy, Catherine A.; White, Mary Anne; Wilkinson, Angus P.; Varga, Tamas

    2007-06-01

    We explore the lattice dynamics of the negative thermal expansion material, cubic HfMo2O8 , through analysis of its heat capacity (measured from 0.5to300K ) and its room-temperature Raman spectrum. Its heat capacity is quantitatively very similar to that of ZrW2O8 , as is its Raman spectrum. The heat capacity of HfMo2O8 can be well represented by the present lattice dynamical assignment and by CP(HfW2O8)-CP(ZrW2O8)+CP(ZrMo2O8) , but not by CP(HfO2)+2CP(MoO3) , likely because the AB2O8 compounds have low-frequency optic modes, not present in HfO2 and MoO3 . The present thermodynamic data also allow an analysis of the thermodynamic stability of cubic HfMo2O8 , and it is shown to be unstable with respect to MoO3 and HfO2 at room temperature.

  3. The determination of values of the specific heat capacity of the selected thermal insulation materials used in track bed structure

    Directory of Open Access Journals (Sweden)

    Dobeš Peter

    2017-01-01

    Full Text Available The report concentrates on the determination of the specific heat capacity of the selected thermal insulation materials (liapor, styrodur, foam concrete. The aim of the report is to gain the necessary input parameters for the numerical modelling of the temperature changes of various track bed structures of the railway line where a part or, if appropriate, the whole protective layer is replaced by the material with better thermal insulation properties. There are described the methods for stating the specific heat capacity as well as the calibration of the calorimeter for stating of the calorimetric constant in the introduction of the report. The parameters needed for calculation of the specific heat capacity of the selected thermal insulation materials are characterized in the second part of the report. There are also introduced the laboratory stated values of the parameter in question. The comparison of the values stated by the laboratory measurements with the values introduced in the technical data sheets from their producers (or if appropriate gained from the foreign sources is made in the conclusion of the report.

  4. Heat-capacity changes in host-guest complexation by Coulomb interactions in aqueous solution.

    Science.gov (United States)

    Kano, Koji; Ishida, Yoshiyuki; Kitagawa, Kohei; Yasuda, Mayuko; Watanabe, Maki

    2007-10-01

    Heat-capacity changes (deltaC(p)0) were determined for the complexation of 1-alkanecarboxylates with protonated hexakis(6-amino-6-deoxy)-alpha-cyclodextrin (per-NH3(+)-alpha-CD) and heptakis(6-amino-6-deoxy)-beta-cyclodextrin (per-NH3(+)-beta-CD). DeltaC(p)0 decreased with an increase in the binding constant (K) and plateaued at K = 4000 M(-1). The complexes of 1-pentanoate, 1-hexanoate, and 1-heptanoate with per-NH3(+)-alpha-CD are classified as the host-guest system in which the size of the guest fits the CD cavity well. In such a system, van der Waals interaction is the major force for complexation, leading to a negative deltaH0 value. Simultaneously, the water molecules around the hydrophobic alkyl chain of the guest and inside the CD cavity are released to the aqueous bulk phase, leading to a positive deltaS0 value. The negative deltaC(p)0 value in such complexation is ascribed to dehydration of the hydrophobic alkyl chain of the guest and extrusion of the water molecules inside the CD cavity. Meanwhile, the complexes that show positive deltaC(p)0 values are characterized by complexation in which the guest molecules are significantly smaller than the CD cavities. In such a case, the complexation is endothermic and driven by the entropy gain. When the guest is much smaller than the CD cavity, the main binding force should be Coulomb interaction. To form an ionic bond, dehydration of the charged groups must occur. This process is endothermic and leads to positive deltaH0 and deltaS0 values. As the top of the CD cavity is capped by a small but hydrophobic alkyl chain, the water molecules inside the CD cavity may form the iceberg structure. This process must be accompanied by a positive deltaC(p)0 value. Hence, the complexation of a small guest with the CD with a large cavity through Coulomb interactions shows positive and large deltaC(p)0 values. These conclusions were applied to the electrostatic binding of proteins with an anionic ligand.

  5. Synthesis of CeO2-based core/shell nanoparticles with high oxygen storage capacity

    Science.gov (United States)

    Uzunoglu, Aytekin; Kose, Dursun Ali; Stanciu, Lia A.

    2017-07-01

    Ceria plays a key role in various applications including sensing and catalysis owing to its high oxygen storage capacity (OSC). The aim of this work is to prepare novel MO x /CeO2 (M: Zr, Ti, Cu) metal oxide systems with core/shell structures using a facile two-step chemical precipitation method. The synthesized nanoparticles were characterized using X-ray diffraction (XRD), transmission electron microscopy (TEM), and N2 adsorption methods. The OSC property of the samples was evaluated using TGA analysis conducted at 600 °C under reductive (5% H2/Ar) and oxidative (synthetic air) environments. The OSCs of the samples were found to be 130, 253, and 2098 µmol-O2/g for ZrO2/CeO2, TiO2/CeO2, and CuO/CeO2, respectively. Effects of heat treatment on the physical and redox properties of the samples were also evaluated. In this regard, the samples were exposed to 500 °C for 5 h under ambient environment. It was observed that the heat treatment induced the formation of mixed metal oxide alloys and the BET surface area of the samples diminished significantly. The OSC of the samples, however, did not experience any significant chance, which was attributed to the compensation of the loss in the surface area by the alloy formation after the heat treatment.

  6. Baseline high heat flux and plasma facing materials for fusion

    Science.gov (United States)

    Ueda, Y.; Schmid, K.; Balden, M.; Coenen, J. W.; Loewenhoff, Th.; Ito, A.; Hasegawa, A.; Hardie, C.; Porton, M.; Gilbert, M.

    2017-09-01

    In fusion reactors, surfaces of plasma facing components (PFCs) are exposed to high heat and particle flux. Tungsten and Copper alloys are primary candidates for plasma facing materials (PFMs) and coolant tube materials, respectively, mainly due to high thermal conductivity and, in the case of tungsten, its high melting point. In this paper, recent understandings and future issues on responses of tungsten and Cu alloys to fusion environments (high particle flux (including T and He), high heat flux, and high neutron doses) are reviewed. This review paper includes; Tritium retention in tungsten (K. Schmid and M. Balden), Impact of stationary and transient heat loads on tungsten (J.W. Coenen and Th. Loewenhoff), Helium effects on surface morphology of tungsten (Y. Ueda and A. Ito), Neutron radiation effects in tungsten (A. Hasegawa), and Copper and copper alloys development for high heat flux components (C. Hardie, M. Porton, and M. Gilbert).

  7. Surface and bulk modified high capacity layered oxide cathodes with low irreversible capacity loss

    Science.gov (United States)

    Manthiram, Arumugam (Inventor); Wu, Yan (Inventor)

    2010-01-01

    The present invention includes compositions, surface and bulk modifications, and methods of making of (1-x)Li[Li.sub.1/3Mn.sub.2/3]O.sub.2.xLi[Mn.sub.0.5-yNi.sub.0.5-yCo.sub.2- y]O.sub.2 cathode materials having an O3 crystal structure with a x value between 0 and 1 and y value between 0 and 0.5, reducing the irreversible capacity loss in the first cycle by surface modification with oxides and bulk modification with cationic and anionic substitutions, and increasing the reversible capacity to close to the theoretical value of insertion/extraction of one lithium per transition metal ion (250-300 mAh/g).

  8. Optimized tissue heating by adopting high frequency electrotherapy

    Directory of Open Access Journals (Sweden)

    Jae-cheol Lee

    2015-11-01

    Full Text Available We have developed an electronics circuit that generates a high voltage with a frequency of 0.3–2 MHz to build an electro therapy system that can optimize tissue heating characteristics. These characteristics are used in medical applications. This paper is focused on the analysis of high frequency electro-therapy system to optimize tissue heating with the help of a high voltage pulse signal, which peak voltage is almost 2 kV. This optimized tissue heating between the inner tissue and the thermal distributions has examined in terms of frequency and voltage. The target tissue heating is composed of a single electrode in an experiment that has especially conducted to find the tissue heating characteristics. In the end, a new method for electro-therapy is developed, which is applicable to a specific tissue depth.

  9. Programmatic status of NASA`s CSTI high capacity power Stirling Space Power Converter Program

    Energy Technology Data Exchange (ETDEWEB)

    Dudenhoefer, J.E.

    1994-09-01

    An overview is presented of the NASA Lewis Research Center Free-Piston Stirling Space Power Converter Technology Development Program. This work is being conducted under NASA`s Civil Space Technology Initiative (CSTI). The goal of the CSTI High Capacity Power element is to develop the technology base needed to meet the long duration, high capacity power requirements for future NASA space initiatives. Efforts are focused upon increasing system thermal and electric energy conversion efficiency at least fivefold over current SP-100 technology, and on achieving systems that are compatible with space nuclear reactors. This paper will discuss the status of test activities with the Space Power Research Engine (SPRE). Design deficiencies are gradually being corrected and the power converter is now outputting 11.5 kWe at a temperature ratio of 2 (design output is 12.5 kWe). Detail designs have been completed for the 1050 K Component Test Power Converter (CTPC). The success of these and future designs is dependent upon supporting research and technology efforts including heat pipes, gas bearings, superalloy joining technologies and high efficiency alternators. This paper also provides an update of progress in these technologies.

  10. Heat pumps; Synergy of high efficiency and low carbon electricity

    Energy Technology Data Exchange (ETDEWEB)

    Koike, Akio

    2010-09-15

    Heat pump is attracting wide attention for its high efficiency to utilize inexhaustible and renewable ambient heat in the environment. With its rapid innovation and efficiency improvement, this technology has a huge potential to reduce CO2 emissions by replacing currently widespread fossil fuel combustion systems to meet various heat demands from the residential, commercial and industrial sectors. Barriers to deployment such as low public awareness and a relatively long pay-back period do exist, so it is strongly recommended that each country implement policies to promote heat pumps as a renewable energy option and an effective method to combat global warming.

  11. Measurement of the Electronic Thermal Conductance Channels and Heat Capacity of Graphene at Low Temperature

    Directory of Open Access Journals (Sweden)

    Kin Chung Fong

    2013-10-01

    Full Text Available The ability to transport energy is a fundamental property of the two-dimensional Dirac fermions in graphene. Electronic thermal transport in this system is relatively unexplored and is expected to show unique fundamental properties and to play an important role in future applications of graphene, including optoelectronics, plasmonics, and ultrasensitive bolometry. Here, we present measurements of bipolar thermal conductances due to electron diffusion and electron-phonon coupling and infer the electronic specific heat, with a minimum value of 10k_{B} (10^{-22}  J/K per square micron. We test the validity of the Wiedemann-Franz law and find that the Lorenz number equals 1.32×(π^{2}/3(k_{B}/e^{2}. The electron-phonon thermal conductance has a temperature power law T^{2} at high doping levels, and the coupling parameter is consistent with recent theory, indicating its enhancement by impurity scattering. We demonstrate control of the thermal conductance by electrical gating and by suppressing the diffusion channel using NbTiN superconducting electrodes, which sets the stage for future graphene-based single-microwave photon detection.

  12. Heat capacity studies of single-crystalline CePt{sub 4}In

    Energy Technology Data Exchange (ETDEWEB)

    Pikul, A.P. [Polish Academy of Sciences, Institute of Low Temperature and Structure Research, P Nr 1410, 50-950 Wroclaw 2 (Poland); Max Planck Institute for Chemical Physics of Solids, Noethnitzer Str. 40, 01187 Dresden (Germany)], E-mail: A.Pikul@int.pan.wroc.pl; Kaczorowski, D.; Bukowski, Z. [Polish Academy of Sciences, Institute of Low Temperature and Structure Research, P Nr 1410, 50-950 Wroclaw 2 (Poland); Steglich, F. [Max Planck Institute for Chemical Physics of Solids, Noethnitzer Str. 40, 01187 Dresden (Germany)

    2008-04-01

    Single crystals of CePt{sub 4}In have been studied by means of specific heat measurements performed at low temperatures (down to 60 mK) and in high magnetic fields (up to 9 T). In zero magnetic field the {delta}C/T ratio strongly increases with decreasing temperature down to about 250 mK, where a broad maximum ({approx}1.75Jmol{sup -1}K{sup -2}) occurs. At lower temperatures {delta}C/T slightly diminishes and finally saturates at a value of about 1.7Jmol{sup -1}K{sup -2}. Upon applying magnetic field the maximum in {delta}C/T(T) disappears (it is not visible already in 0.5 T) and the magnitude of {delta}C/T becomes significantly lower. We argue that the observed anomaly in {delta}C(T)/T is due to some magnetic ordering of the cerium magnetic moments, in line with our previous statement on the localized character of the 4f-electrons in this compound.

  13. ESTIMATIONS OF HEAT CAPACITIES FOR ACTINIDE DIOXIDE: UO2, NpO2, ThO2, AND PuO2

    Directory of Open Access Journals (Sweden)

    E. ESER

    2014-12-01

    Full Text Available The evaluation of thermal properties of actinide oxide fuels is a problem of high importance for the development of new generation reactors. In the present study, an expression obtained for n-dimensional Debye functions is used to derive a simple analytical expression for the specific heat capacity of nuclear fuels. To test the validity and reliability of this expression, the analytical expression is applied to UO2, NpO2, ThO2, and PuO2. It is seen that the formula was in agreement with the experimental and theoretical results reported in the literature.

  14. Direct experimental evidence for a negative heat capacity in the liquid-to-gas like phase transition in hydrogen cluster ions backbending of the caloric curve

    CERN Document Server

    Gobet, F; Carré, M; Farizon, B; Farizon, M; Gaillard, M J; Maerk, T D; Scheier, P

    2002-01-01

    By (i) selecting specific decay reactions in high energy collisions (60 keV/amu) of hydrogen cluster ions with a helium target (utilizing event-by-event data of a recently developed multi-coincidence experiment) and by (ii) deriving corresponding temperatures for these microcanonical cluster ensembles (analyzing the respective fragment distributions) we are able to construct caloric curves for ii sub 3 sup + (ii sub 2) sub m cluster ions (6 <= m <= 14). All individual curves and the mean of these curves show a backbending in the plateau region thus constituting direct evidence for a negative microcanonical heat capacity in the liquid-to-gas like transition of these finite systems.

  15. An automated flow calorimeter for heat capacity and enthalpy measurements at elevated temperatures and pressures: Progress report for period March 1, 1988--February 29, 1989

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.

    1988-10-30

    The need for thermal property data at process conditions has been well documented in applications such as development of atmospherically inert refrigerants and design of petrochemical and synfuel plants. As such, the primary objective of this work is to construct an automated flow calorimeter to measure isobaric heat capacities and enthalpies of vaporization over the range 0--30MPa and 300--700K with an anticipated accuracy of 0.1%. The method of measurement is an adiabatic electrical power input technique with a unique calorimeter design utilizing a concentric coil/radiation shield structure which minimizes heat loss errors and simplifies the replacement of plugged components. Flow generation is accomplished with a precision Ruska pump eliminating the need for on-line flow rate measurement. In addition, the proposed instrument will be fully automated minimizing the need for highly skilled operators which had previously been a severe limitation with this type of instrument. Assembly of all hardware and implementation of the necessary software was completed within the past year. In addition, water was used as a heat capacity standard to evaluate overall system performance. Preliminary indications are that the apparatus is operating near expectations (+//minus/0.2%) although some additional hardware refinements may be necessary achieve the design goals of +//minus/0.1%. 15 refs., 4 figs., 1 tab.

  16. Heat capacity of quantum adsorbates: Hydrogen and helium on evaporated gold films

    Energy Technology Data Exchange (ETDEWEB)

    Birmingham, J.T. [Univ. of California, Berkeley, CA (United States). Dept. of Physics]|[Lawrence Berkeley National Lab., CA (United States). Materials Sciences Div.

    1996-06-01

    The author has constructed an apparatus to make specific heat measurements of quantum gases adsorbed on metallic films at temperatures between 0.3 and 4 K. He has used this apparatus to study quench-condensed hydrogen films between 4 and 923 layers thick with J = 1 concentrations between 0.28 and 0.75 deposited on an evaporated gold surface. He has observed that the orientational ordering of the J = 1 molecules depends on the substrate temperature during deposition of the hydrogen film. He has inferred that the density of the films condensed at the lowest temperatures is 25% higher than in bulk H{sub 2} crystals and have observed that the structure of those films is affected by annealing at 3.4 K. The author has measured the J = 1 to J = 0 conversion rate to be comparable to that of the bulk for thick films; however, he found evidence that the gold surface catalyzes conversion in the first two to four layers. He has also used this apparatus to study films of {sup 4}He less than one layer thick adsorbed on an evaporated gold surface. He shows that the phase diagram of the system is similar to that for {sup 4}He/graphite although not as rich in structure, and the phase boundaries occur at different coverages and temperatures. At coverages below about half a layer and at sufficiently high temperatures, the {sup 4}He behaves like a two-dimensional noninteracting Bose gas. At lower temperatures and higher coverages, liquidlike and solidlike behavior is observed. The Appendix shows measurements of the far-infrared absorptivity of the high-{Tc} superconductor La{sub 1.87}Sr{sub 0.13}CuO{sub 4}.

  17. Ice ingestion with a long rest interval increases the endurance exercise capacity and reduces the core temperature in the heat.

    Science.gov (United States)

    Naito, Takashi; Iribe, Yuka; Ogaki, Tetsuro

    2017-01-05

    The timing in which ice before exercise should be ingested plays an important role in optimizing its success. However, the effects of differences in the timing of ice ingestion before exercise on cycling capacity, and thermoregulation has not been studied. The aim of the present study was to assess the effect of length of time after ice ingestion on endurance exercise capacity in the heat. Seven males ingested 1.25 g kg body mass-1 of ice (0.5 °C) or cold water (4 °C) every 5 min, six times. Under three separate conditions after ice or water ingestion ([1] taking 20 min rest after ice ingestion, [2] taking 5 min rest after ice ingestion, and [3] taking 5 min rest after cold water ingestion), seven physically active male cyclists exercised at 65% of their maximal oxygen uptake to exhaustion in the heat (35 °C, 30% relative humidity). Participants cycled significantly longer following both ice ingestion with a long rest interval (46.0 ± 7.7 min) and that with a short rest interval (38.7 ± 5.7 min) than cold water ingestion (32.3 ± 3.2 min; both p Heat storage under condition of ice ingestion with a long rest interval during the pre-exercise period was significantly lower than that observed with a short rest interval (-4.98 ± 2.50 W m-2; p heat, which is suggested to be driven by a reduced rectal temperature and heat storage before the start of exercise.

  18. 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 Caffeine decreased (p caffeine was associated with a shorter time to exhaustion. In conclusion, acute caffeine ingestion increases HR and blood lactate levels during 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.

  19. High Effectiveness Heat Exchanger for Cryogenic Refrigerators Project

    Data.gov (United States)

    National Aeronautics and Space Administration — We propose an innovative high performance cryogenic heat exchanger manufactured of titanium by photo-etching and diffusion bonding. This is a parallel plate design...

  20. Heat injury prevention practices in high school football.

    Science.gov (United States)

    Luke, Anthony C; Bergeron, Michael F; Roberts, William O

    2007-11-01

    To survey high school American football programs regarding current prevention measures for reducing heat injuries during the football season. Web-based survey of 27 questions based on consensus statement guidelines by the American College of Sports Medicine on reducing heat injury risk in youth football. National (United States) and community-based. High school programs receiving survey distribution from their state athletic association and the National Federation of State High School Associations. Responses (percentage and incidence) to questions on preseason acclimatization procedures, practice modification protocols, preparticipation risk factors, hydration management strategies, rest period strategies, heat injury education and policies, and preparation for heat-related emergency care. A total of 540 high school football programs from 26 states completed the survey. The reported number of preseason heat injuries per program (1.38+/-2.08) was greater (Phigh school American football is needed. Strategies should focus on modifying practices appropriately on a day-to-day basis to minimize heat strain and optimize hydration, identifying and educating at-risk individuals during the preparticipation period, and developing an emergency action plan for effectively managing heat injuries.

  1. 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.

  2. Building physics: wood fiber plates - insulating materials as a heat storage system; Bauphysik: Holzfaserdaemmplatten - Daemmstoffe als Waermespeicher

    Energy Technology Data Exchange (ETDEWEB)

    Hauser, G.

    2006-12-13

    A high heat storage cabability is very effectful due to summer heat behaviour. Advanced heat insulating materials with high heat capacities and raw densities enable the enhancement of heat storage without losses on thermal protection. (GL)

  3. High-Power Liquid-Metal Heat-Transfer Loop

    Science.gov (United States)

    Bhandari, Pradeep; Fujita, Toshio

    1991-01-01

    Proposed closed-loop system for transfer of thermal power operates at relatively high differential pressure between vapor and liquid phases of liquid-metal working fluid. Resembles "capillary-pumped" liquid-metal heat-transfer loop except electric field across permselective barrier of beta alumina keeps liquid and vapor separate at heat-input end. Increases output thermal power, contains no moving parts, highly reliable and well suited to long-term unattended operation.

  4. 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.

  5. Heat dissipation of high rate Li-SOCl sub 2 primary cells

    Science.gov (United States)

    Cho, Y. I.; Halpert, G.; Deligiannis, E.

    1986-01-01

    The heat dissipation problem occurring in the lithium thionyl chloride cells discharged at relatively high rates under normal discharge conditions is examined. Four heat flow paths were identified, and the thermal resistances of the relating cell components along each flow path were accordingly calculated. From the thermal resistance network analysis, it was demonstrated that about 90 percent of the total heat produced within the cell should be dissipated along the radial direction in a spirally wound cell. In addition, the threshold value of the heat generation rate at which cell internal temperature could be maintained below 100 C, was calculated from total thermal resistance and found to be 2.9 W. However, these calculations were made only at the cell components' level, and the transient nature of the heat accumulation and dissipation was not considered. A simple transient model based on the lumped-heat-capacity concept was developed to predict the time-dependent cell temperature at different discharge rates. The overall objective was to examine the influence of cell design variable from the heat removal point of view under normal discharge conditions and to make recommendations to build more efficient lithium cells.

  6. 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

    2018-01-15

    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.

  7. Pulsed sonication for alumina coatings on high-capacity oxides: Performance in lithium-ion cells

    Science.gov (United States)

    Pol, Vilas G.; Li, Yan; Dogan, Fulya; Secor, Ethan; Thackeray, Michael M.; Abraham, Daniel P.

    2014-07-01

    High-capacity xLi2MnO3·(1 - x)LiMO2 (M = Ni, Mn, Co) oxides show relatively rapid performance degradation when cycled at voltages >4.5 V vs. Li/Li+. Previous research has indicated that modifying the oxide surfaces with coatings, such as alumina, reduces cell impedance rise and improves capacity retention. In this article, we demonstrate pulsed-sonication as a rapid and effective approach for coating alumina on Li1.2Ni0.175Mn0.525Co0.1O2 (0.5Li2MnO3·0.5LiNi0.44Mn0.31Co0.25O2) particles. Oxide integrity and morphology is maintained after the sonochemical process and subsequent heat-treatment. Energy dispersive spectroscopy (EDS) X-ray elemental maps show uniform coating of all secondary particles. 27Al Magic Angle Spinning (MAS) NMR data confirm the presence of alumina and mainly indicate octahedral aluminum occupancy in a six-coordinate environment with oxygen. Full cells containing electrodes with the alumina-coated particles demonstrate lower initial impedance rise and better capacity retention during extended cycling to high voltages. However, the coating has a negligible effect on the voltage hysteresis and voltage fade behavior displayed by these oxides. The various data indicate that the pulsed sonochemical technique is a viable approach for coating oxide particles. The methodology described herein can easily be extended beyond alumina to include coatings such as AlF3, MgO, and MgF2.

  8. Pulsed sonication for alumina coatings on high-capacity oxides: Performance in lithium-ion cells

    Energy Technology Data Exchange (ETDEWEB)

    Pol, Vilas G.; Li, Yan; Dogan, Fulya; Secor, Ethan; Thackeray, Michael M.; Abraham, Daniel P.

    2014-07-01

    High-capacity xLi2MnO3•(1-x)LiMO2 (M=Ni, Mn, Co) oxides show relatively rapid performance degradation when cycled at voltages >4.5V vs. Li/Li+. Previous research has indicated that modifying the oxide surfaces with coatings, such as alumina, reduces cell impedance rise and improves capacity retention. In this article, we demonstrate pulsed-sonication as a rapid and effective approach for coating alumina on Li1.2Ni0.175Mn0.525Co0.1O2 (0.5Li2MnO3•0.5LiNi0.44Mn0.31Co0.25O2) particles. Oxide integrity and morphology is maintained after the sonochemical process and subsequent heat-treatment. Energy dispersive spectroscopy (EDS) X-ray elemental maps show uniform coating of all secondary particles. 27Al Magic Angle Spinning (MAS) NMR data confirm the presence of alumina and mainly indicate octahedral aluminum occupancy in a six-coordinate environment with oxygen. Full cells containing electrodes with the alumina-coated particles demonstrate lower initial impedance rise and better capacity retention during extended cycling to high voltages. However, the coating has a negligible effect on the voltage hysteresis and voltage fade behavior displayed by these oxides. The various data indicate that the pulsed sonochemical technique is a viable approach for coating oxide particles. The methodology described herein can easily be extended beyond alumina to include coatings such as AlF3, MgO, and MgF2.

  9. Numerical simulation of high power LED heat-dissipating system

    Science.gov (United States)

    Wu, Shih-Jeh; Hsu, Hsiang-Chen; Fu, Shen-Li; Yeh, Jiam-Nan

    2014-03-01

    In this paper, thermal analysis of the heat dissipation under different heat sink for high-power white Light Emitting Diode (LED) is presented. Junction temperature of LED is elevated as the power of LED increases, which brings up deterioration of light efficiency and other side effects. Heat dissipation is another design concern other than material and illumination efficiency. The purpose of this paper is to investigate the cooling of high-power LED chips and modules for design of heat sinks. Three types of heat sinks are designed for a tandem 12-chip module and an extensive numerical investigation of the heat sink design performance is conducted by Computational Fluid Dynamics software Fluent. The effects of heat sink geometry and adhesive material are also investigated. Design variables are the thickness of sink base, number, thickness and length of fins. The total wetted area is the dominant factor to the junction temperature. The objective of design regarding the junction temperatures around 50°C is easily achieved. However, its effect is limited at high values of these parameters, furthermore an excessive number of fins incurs reverse consequence due to problem of ventilation also waste of material.

  10. Phase Change Material Systems for High Temperature Heat Storage.

    Science.gov (United States)

    Perraudin, David Y S; Binder, Selmar R; Rezaei, Ehsan; Ortonaa, Alberto; Haussener, Sophia

    2015-01-01

    Efficient, cost effective, and stable high-temperature heat storage material systems are important in applications such as high-temperature industrial processes (metal processing, cement and glass manufacturing, etc.), or electricity storage using advanced adiabatic compressed air energy storage. Incorporating phase change media into heat storage systems provides an advantage of storing and releasing heat at nearly constant temperature, allowing steady and optimized operation of the downstream processes. The choice of, and compatibility of materials and encapsulation for the phase change section is crucial, as these must guarantee good and stable performance and long lifetime at low cost. Detailed knowledge of the material properties and stability, and the coupled heat transfer, phase change, and fluid flow are required to allow for performance and lifetime predictions. We present coupled experimental-numerical techniques allowing prediction of the long-term performance of a phase change material-based high-temperature heat storage system. The experimental investigations focus on determination of material properties (melting temperature, heat of fusion, etc.) and phase change material and encapsulation interaction (stability, interface reactions, etc.). The computational investigations focus on an understanding of the multi-mode heat transfer, fluid flow, and phase change processes in order to design the material system for enhanced performance. The importance of both the experimental and numerical approaches is highlighted and we give an example of how both approaches can be complementarily used for the investigation of long-term performance.

  11. Methodology for DSC calibration in high heating rates

    Directory of Open Access Journals (Sweden)

    Carlos Isidoro Braga

    2011-05-01

    Full Text Available Despite the large use of differential scanning calorimetry (DSC technique in advanced polymer materials characterization, the new methodology called DSC in high heating rates was developed. The heating rate during conventional DSC experiments varying from 10 to 20ºC.min-¹, sample mass from 10 to 15mg and standard aluminum sample pan weighting, approximately, 27mg. In order to contribute to a better comprehension of DSC behavior in different heating rates, this work correlates as high heating rate influences to the thermal events in DSC experiments. Samples of metallic standard (In, Pb, Sn and Zn with masses varying from 0.570mg to 20.9mg were analyzed in multiples sample heating rate from 4 to 324°C. min-¹. In order to make properly all those experiments, a precise and careful temperature and enthalpy calibrations were performed and deeply discussed. Thus, this work shows a DSC methodology able to generate good and reliable results on experiments under any researcher choice heating rates to characterize the advanced materials used, for example, for aerospace industry. Also it helps the DSC users to find in their available instruments, already installed, a better and more accurate DSC test results, improving in just one shot the analysis sensitivity and resolution. Polypropylene melting and enthalpy thermal events are also studied using both the conventional DSC method and high heating rate method.

  12. Low Temperature Heating and High Temperature Cooling in Buildings

    DEFF Research Database (Denmark)

    Kazanci, Ongun Berk

    , a single-family house designed for plus-energy targets and equipped with a radiant water-based floor heating and cooling system was studied by means of full-scale measurements, dynamic building simulations and thermodynamic evaluation tools. Thermal indoor environment and energy performance of the house......A heating and cooling system could be divided into three parts: terminal units (emission system), distribution system, and heating and cooling plant (generation system). The choice of terminal unit directly affects the energy performance, and the indoor environment in that space. Therefore......, a holistic system evaluation is necessary to ensure an optimal indoor environment for the occupants and to achieve energy efficiency simultaneously. Low temperature heating and high temperature cooling systems are one of the possible approaches to heat or cool indoor spaces in buildings. In this thesis...

  13. High-capacity electrode materials for electrochemical energy storage

    Indian Academy of Sciences (India)

    2015-06-02

    Jun 2, 2015 ... electrolyte to form a decomposition product that can be detrimental to capacity retention and cycle life. To stabilize such interface reactivity, the surface of the cathode particle is coated with inorganic oxides that are conducive to lithium transport. There have been numerous examples in literature in the ...

  14. IMP improves water-holding capacity, physical and sensory properties of heat-induced gels from porcine meat.

    Science.gov (United States)

    Nakamura, Yukinobu; Migita, Koshiro; Okitani, Akihiro; Matsuishi, Masanori

    2014-05-01

    Water-holding capacity (WHC) of heat-induced pork gels was examined. The heat-induced gels were obtained from meat homogenates prepared by adding nine volumes of 0.3-0.5 mol/L NaCl solutions containing 9-36 mmol/L disodium inosine-5'-monophosphate (IMP) or 9 mmol/L tetrapotassium pyrophosphate (KPP) to minced pork. IMP at 36 mmol/L enhanced the WHC to the same level as attained by KPP. Physical and sensory properties of heat-induced gels were also examined. The heat-induced gels were prepared from porcine meat homogenates containing 0.3 mol/L NaCl and 9-36 mmol/L IMP or 9 mmol/L KPP. IMP at 36 mmol/L enhanced the values of hardness, cohesiveness, gumminess and springiness, measured with a Tensipresser, and several organoleptic scores to the same level as the score attained by KPP. Thus, it is concluded that IMP is expected to be a practical substitute for pyrophosphates to improve the quality of sausages. © 2014 Japanese Society of Animal Science.

  15. FEM Simulation of the Effect of Coefficient of Thermal Expansion and Heat Capacity on Prediction of Residual Stresses of Compression Molded Glass Lenses

    Science.gov (United States)

    Tao, Bo; Yuan, Ye

    2017-11-01

    In this research, the effects of the coefficient of thermal expansion (CTE) and heat capacity on the prediction of residual stresses in BK7 compression molded glass lenses were studied. Three different groups of CTE and two different kinds of heat capacity, which are constant and proportional to temperature, were chosen to investigate the impacts of residual stresses. The simulation results show a big difference and suggest that the properties of glass materials determine the residual stresses and should be measured carefully.

  16. 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.

  17. Labworks and the Kundt's Tube: A New Way to Determine the Heat Capacities of Gases

    Science.gov (United States)

    Bryant, Philip A.; Morgan, Matthew E.

    2004-01-01

    The potency of heat in gases is measured by the application of a computer and the LabWorks interaction, while the speed of sound in gases is determined by an instrument called Kundt's tube. This unique and accurate procedure is repeatable, and greatly reduces data acquisition time.

  18. Using heat demand prediction to optimise Virtual Power Plant production capacity

    NARCIS (Netherlands)

    Bakker, Vincent; Molderink, Albert; Hurink, Johann L.; Smit, Gerardus Johannes Maria

    2008-01-01

    In the coming decade a strong trend towards distributed electricity generation (microgeneration) is expected. Micro-generators are small appliances that generate electricity (and heat) at the kilowatt level, which allows them to be installed in households. By combining a group of micro-generators, a

  19. Low-temperature heat capacities and Raman spectra of negative thermal expansion compounds ZrW2O8 and HfW2O8

    Science.gov (United States)

    Yamamura, Yasuhisa; Nakajima, Noriyuki; Tsuji, Toshihide; Koyano, Mikio; Iwasa, Yoshihiro; Katayama, Shin'ichi; Saito, Kazuya; Sorai, Michio

    2002-06-01

    Heat capacities of ZrW2O8 and HfW2O8 were precisely measured between 1.8 and 330 K. Heat-capacity curves of ZrW2O8 and HfW2O8 are very similar to each other. The heat capacity of HfW2O8 at low temperature is larger than that of ZrW2O8 due to atomic mass effect, but both heat capacities cross around 220 K. Raman spectra of ZrW2O8 and HfW2O8 were recorded at room temperature. Frequency distributions of lattice vibrations were estimated through an analysis of the heat capacities for ZrW2O8 and HfW2O8. It is found that the difference in the frequency distributions between ZrW2O8 and HfW2O8 arises from the different atomic mass and bond strength, and causes the different temperature dependence of the heat capacities. The properties of the optical-phonon modes with a large negative mode-Grüneisen parameter are discussed.

  20. Size-dependence of the heat capacity and thermodynamic properties of hematite ({alpha}-Fe{sub 2}O{sub 3})

    Energy Technology Data Exchange (ETDEWEB)

    Snow, Claine L.; Lee, Christopher R.; Shi, Quan; Boerio-Goates, Juliana [Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602 (United States); Woodfield, Brian F., E-mail: brian_woodfield@byu.ed [Department of Chemistry and Biochemistry, Brigham Young University, Provo, UT 84602 (United States)

    2010-09-15

    The heat capacity of a 13 nm hematite ({alpha}-Fe{sub 2}O{sub 3}) sample was measured from T = (1.5 to 350) K using a combination of semi-adiabatic and adiabatic calorimetry. The heat capacity was higher than that of the bulk which can be attributed to the presence of water on the surface of the nanoparticles. No anomaly was observed in the heat capacity due to the Morin transition and theoretical fits of the heat capacity below T = 15 K show a small T{sup 3} dependence (due to lattice contributions) with no T{sup 3/2} dependence. This suggests that there are no magnetic spin-wave contributions to the heat capacity of 13 nm hematite. The use of a large linear term to fit the heat capacity below T = 15 K is most likely due to superparamagnetic contributions. A small anomaly within the temperature range (4 to 8) K was attributed to the presence of uncompensated surface spins.

  1. Crystalline-amorphous core-shell silicon nanowires for high capacity and high current battery electrodes.

    Science.gov (United States)

    Cui, Li-Feng; Ruffo, Riccardo; Chan, Candace K; Peng, Hailin; Cui, Yi

    2009-01-01

    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 ( approximately 1000 mAh/g, 3 times of carbon) with approximately 90% capacity retention over 100 cycles. They also show excellent electrochemical performance at high rate charging and discharging (6.8 A/g, approximately 20 times of carbon at 1 h rate).

  2. 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.

  3. Numerical prediction of nucleate pool boiling heat transfer coefficient under high heat fluxes

    Directory of Open Access Journals (Sweden)

    Pezo Milada L.

    2016-01-01

    Full Text Available This paper presents CFD (Computational Fluid Dynamics approach to prediction of the heat transfer coefficient for nucleate pool boiling under high heat fluxes. Three-dimensional numerical simulations of the atmospheric saturated pool boiling are performed. Mathematical modelling of pool boiling requires a treatment of vapor-liquid two-phase mixture on the macro level, as well as on the micro level, such as bubble growth and departure from the heating surface. Two-phase flow is modelled by the two-fluid model, which consists of the mass, momentum and energy conservation equations for each phase. Interface transfer processes are calculated by the closure laws. Micro level phenomena on the heating surface are modelled with the bubble nucleation site density, the bubble resistance time on the heating wall and with the certain level of randomness in the location of bubble nucleation sites. The developed model was used to determine the heat transfer coefficient and results of numerical simulations are compared with available experimental results and several empirical correlations. A considerable scattering of the predictions of the pool boiling heat transfer coefficient by experimental correlations is observed, while the numerically predicted values are within the range of results calculated by well-known Kutateladze, Mostinski, Kruzhilin and Rohsenow correlations. The presented numerical modeling approach is original regarding both the application of the two-fluid two-phase model for the determination of heat transfer coefficient in pool boiling and the defined boundary conditions at the heated wall surface. [Projekat Ministarstva nauke Republike Srbije, br. 174014

  4. High heat transfer oxidizer heat exchanger design and analysis. [RL10-2B engine

    Science.gov (United States)

    Kmiec, Thomas D.; Kanic, Paul G.; Peckham, Richard J.

    1987-01-01

    The RL10-2B engine, a derivative of the RL10, is capable of multimode thrust operation. This engine operates at two low thrust levels: tank head idle (THI), which is approximately 1 to 2% of full thrust, and pumped idle (PI), which is 10% of full thrust. Operation at THI provides vehicle propellant settling thrust and efficient engine thermal conditioning; PI operation provides vehicle tank pre-pressurization and maneuver thrust for low-g deployment. Stable combustion of the RL10-2B engine during the low thrust operating modes can be accomplished by using a heat exchanger to supply gaseous oxygen to the propellant injector. The oxidizer heat exchanger (OHE) vaporizes the liquid oxygen using hydrogen as the energy source. The design, concept verification testing and analysis for such a heat exchanger is discussed. The design presented uses a high efficiency compact core to vaporize the oxygen, and in the self-contained unit, attenuates any pressure and flow oscillations which result from unstable boiling in the core. This approach is referred to as the high heat transfer design. An alternative approach which prevents unstable boiling of the oxygen by limiting the heat transfer is referred to as the low heat transfer design and is reported in Pratt & Whitney report FR-19135-2.

  5. On high-order polynomial heat-balance integral implementations

    Directory of Open Access Journals (Sweden)

    Wood Alastair S.

    2009-01-01

    Full Text Available This article reconsiders aspects of the analysis conventionally used to establish accuracy, performance and limitations of the heat balance integral method: theoretical and practical rates of convergence are confirmed for a familiar piecewise heat-balance integral based upon mesh refinement, and the use of boundary conditions is discussed with respect to fixed and moving boundaries. Alternates to mesh refinement are increased order of approximation or non-polynomial approximants. Here a physically intuitive high-order polynomial heat balance integral formulation is described that exhibits high accuracy, rapid convergence, and desirable qualitative solution properties. The simple approach combines a global approximant of prescribed degree with spatial sub-division of the solution domain. As a variational-type method, it can be argued that heat-balance integral is simply 'one amongst many'. The approach is compared with several established variational formulations and performance is additionally assessed in terms of 'smoothness'.

  6. 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

    to suitable time slots and this makes it possible to avoid some grid storage capacity. The energy is bought based on prediction of energy prices, weather forecast and an aggregated house model on the NORD POOL day-ahead market. The bought energy is then distributed to the houses using a model free sorting...... (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....

  7. Molecular simulation of caloric properties of fluids modelled by force fields with intramolecular contributions: Application to heat capacities.

    Science.gov (United States)

    Smith, William R; Jirsák, Jan; Nezbeda, Ivo; Qi, Weikai

    2017-07-21

    The calculation of caloric properties such as heat capacity, Joule-Thomson coefficients, and the speed of sound by classical force-field-based molecular simulation methodology has received scant attention in the literature, particularly for systems composed of complex molecules whose force fields (FFs) are characterized by a combination of intramolecular and intermolecular terms. The calculation of a thermodynamic property for a system whose molecules are described by such a FF involves the calculation of the residual property prior to its addition to the corresponding ideal-gas property, the latter of which is separately calculated, either using thermochemical compilations or nowadays accurate quantum mechanical calculations. Although the simulation of a volumetric residual property proceeds by simply replacing the intermolecular FF in the rigid molecule case by the total (intramolecular plus intermolecular) FF, this is not the case for a caloric property. We describe the correct methodology required to perform such calculations and illustrate it in this paper for the case of the internal energy and the enthalpy and their corresponding molar heat capacities. We provide numerical results for c P , one of the most important caloric properties. We also consider approximations to the correct calculation procedure previously used in the literature and illustrate their consequences for the examples of the relatively simple molecule 2-propanol, CH 3 CH(OH)CH 3 , and for the more complex molecule monoethanolamine, HO(CH 2 ) 2 NH 2 , an important fluid used in carbon capture.

  8. 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}.

  9. Molecular simulation of caloric properties of fluids modelled by force fields with intramolecular contributions: Application to heat capacities

    Science.gov (United States)

    Smith, William R.; Jirsák, Jan; Nezbeda, Ivo; Qi, Weikai

    2017-07-01

    The calculation of caloric properties such as heat capacity, Joule-Thomson coefficients, and the speed of sound by classical force-field-based molecular simulation methodology has received scant attention in the literature, particularly for systems composed of complex molecules whose force fields (FFs) are characterized by a combination of intramolecular and intermolecular terms. The calculation of a thermodynamic property for a system whose molecules are described by such a FF involves the calculation of the residual property prior to its addition to the corresponding ideal-gas property, the latter of which is separately calculated, either using thermochemical compilations or nowadays accurate quantum mechanical calculations. Although the simulation of a volumetric residual property proceeds by simply replacing the intermolecular FF in the rigid molecule case by the total (intramolecular plus intermolecular) FF, this is not the case for a caloric property. We describe the correct methodology required to perform such calculations and illustrate it in this paper for the case of the internal energy and the enthalpy and their corresponding molar heat capacities. We provide numerical results for cP, one of the most important caloric properties. We also consider approximations to the correct calculation procedure previously used in the literature and illustrate their consequences for the examples of the relatively simple molecule 2-propanol, CH3CH(OH)CH3, and for the more complex molecule monoethanolamine, HO(CH2)2NH2, an important fluid used in carbon capture.

  10. Responses to dry heat of men and women with similar aerobic capacities.

    Science.gov (United States)

    Frye, A J; Kamon, E

    1981-01-01

    Four men and four women with similar VO2max (56.33 +/- 4.05 and 54.08 +/- 4.27 ml.kg-1.min-1, respectively) exercised up to 3 h at 30% VO2max during heat stress tests (HST) before and after acclimation to dry heat [dry-bulb temperature (Tdb)/wet-bulb temperature (Twb) = 48/25 degrees C]. Rectal (Tre), tympanic sweat on the chest (msw), and total sweat rate (Msw) were recorded. There were no differences in the responses of the women between phases of the menstrual cycle. Tre, Tty, Tsk, and Tdb at the onset of sweating were similar in both sexes before and after acclimation. The nonacclimated men had significantly higher Msw and slower rise in Tre as compared to the nonacclimated women. Following acclimation these differences were no longer evident. Acclimation produced an increase in Msw in both sexes that was characterized by an increase in sweating sensitivity (delta msw/delta Tre). It was concluded that sex alone does not determine responses to heat stress. Consideration should also be given to the relative cardiovascular strain, state of acclimation, and the ambient conditions.

  11. Temporal Processing Capacity in High-Level Visual Cortex Is Domain Specific.

    Science.gov (United States)

    Stigliani, Anthony; Weiner, Kevin S; Grill-Spector, Kalanit

    2015-09-09

    Prevailing hierarchical models propose that temporal processing capacity--the amount of information that a brain region processes in a unit time--decreases at higher stages in the ventral stream regardless of domain. However, it is unknown if temporal processing capacities are domain general or domain specific in human high-level visual cortex. Using a novel fMRI paradigm, we measured temporal capacities of functional regions in high-level visual cortex. Contrary to hierarchical models, our data reveal domain-specific processing capacities as follows: (1) regions processing information from different domains have differential temporal capacities within each stage of the visual hierarchy and (2) domain-specific regions display the same temporal capacity regardless of their position in the processing hierarchy. In general, character-selective regions have the lowest capacity, face- and place-selective regions have an intermediate capacity, and body-selective regions have the highest capacity. Notably, domain-specific temporal processing capacities are not apparent in V1 and have perceptual implications. Behavioral testing revealed that the encoding capacity of body images is higher than that of characters, faces, and places, and there is a correspondence between peak encoding rates and cortical capacities for characters and bodies. The present evidence supports a model in which the natural statistics of temporal information in the visual world may affect domain-specific temporal processing and encoding capacities. These findings suggest that the functional organization of high-level visual cortex may be constrained by temporal characteristics of stimuli in the natural world, and this temporal capacity is a characteristic of domain-specific networks in high-level visual cortex. Significance statement: Visual stimuli bombard us at different rates every day. For example, words and scenes are typically stationary and vary at slow rates. In contrast, bodies are dynamic

  12. 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.

  13. 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.

    2017-01-01

    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.

  14. 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.

    2017-01-01

    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. PMID:28079171

  15. A high-capacity aeronautical mobile satellite system

    Science.gov (United States)

    Sue, M. K.

    1987-01-01

    This paper describes a conceptual system design for a satellite-based aeronautical safety communications system capable of serving both general aviation aircraft and commercial aviation aircraft in the contiguous U.S. in the mid-1990s. The space segment is described, including satellite locations and coverage, spacecraft configuration, eclipse capability and stationkeeping, transponder design, and mass and power. The spacecraft mass and power budgets are given. The air mobile terminals, ground segment, and frequency plan and channelization are discussed, and the data rate, modulation/demodulation/coding, and channel spacing are considered. The message format, frequency control, system capacity, and system sensitivity are discussed.

  16. Geothermic Power Plants of high capacity - how far?

    OpenAIRE

    R.H. Kozłowski

    2011-01-01

    Purpose: Over the past two hundred years, the mankind has exploited more than 50 percent of all natural resources, including energy minerals. The twenty-first century will be, out of necessity the period of intensive development of energy based on renewable resources.Design/methodology/approach: The average geothermic gradient for the Earth`s crust (30°C/1km) can give us 10-20 MWe as a result (electrical energy) from one deep borehole heat exchanger. The value of electrical energy may be incr...

  17. 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.

  18. High-dynamic-range and high-capacity RF and microwave fiber optic links

    Science.gov (United States)

    Weiss, Frank

    2013-05-01

    Novel fiber optic transmitter control methodologies, high optical power and low RIN source lasers, high performance photodiodes and DWDM laser capability provide high dynamic range and high capacity transport for a wide range of sensing and communications applications. Measured component and system level test data demonstrates these performance improvements. Higher spur free dynamic range in excess of 110 dB·Hz2/3 over broad range of K-band frequencies is demonstrated, increasing the practical use of fiber as a transport method for high sensitivity applications. Multichannel DWDM operation provides simplified capacity expansion without compromising system performance, allowing arrayed photonic systems to be deployed. System characterization for a wide range of optical wavelengths and RF frequencies is provided to demonstrate these levels of performance in practical applications. Photonic component cost reductions combined with compact packaging further increase the ability of high performance fiber optic transport to address a wider range of applications, as the size, weight and performance barriers are eliminated. This paper provides a summary of the current state of the art of commercially available photonic components for high performance externally modulated analog optical links from a practical perspective.

  19. High performance heat sink for surface mount applications

    Science.gov (United States)

    McKeown, Stephen A.; Levasseur, Robert D.

    Surface-mounted electronic module configurations are sensitive to thermal cycling because the reduced compliance between the component and module increases the thermally induced strain in the solder joint. Providing a thermal match between the component and the module reduces this strain, reduces low-cycle fatigue damage, and increases solder joint life. One way of achieving this thermal match is through the use of a thermally matched heat sink. In addition to having the required coefficient of thermal expansion (CTE), heat sinks for surface-mount avionic configurations require low weight and high thermal conductivity. A heat sink has been developed that has thermal conductivity close to aluminum, a CTE close to ceramic, and a weight density only 8 percent higher than aluminum. The flexural modulus of this heat sink is 40 percent higher than aluminum, which results in improved vibration performance.

  20. Startup analysis for a high temperature gas loaded heat pipe

    Science.gov (United States)

    Sockol, P. M.

    1973-01-01

    A model for the rapid startup of a high-temperature gas-loaded heat pipe is presented. A two-dimensional diffusion analysis is used to determine the rate of energy transport by the vapor between the hot and cold zones of the pipe. The vapor transport rate is then incorporated in a simple thermal model of the startup of a radiation-cooled heat pipe. Numerical results for an argon-lithium system show that radial diffusion to the cold wall can produce large vapor flow rates during a rapid startup. The results also show that startup is not initiated until the vapor pressure p sub v in the hot zone reaches a precise value proportional to the initial gas pressure p sub i. Through proper choice of p sub i, startup can be delayed until p sub v is large enough to support a heat-transfer rate sufficient to overcome a thermal load on the heat pipe.

  1. Analysis of frozen startup of high-temperature heat pipes and three-dimensional modeling of block-heated heat pipes

    Science.gov (United States)

    Faghri, Amir

    1991-11-01

    The use of high-temperature heat pipes has been proposed for cooling the leading edges and nose cones of re-entry vehicles, rail guns, and laser mirrors, as well as for the thermal management of future hypersonic vehicle structures. The startup behavior of high temperature heat pipes from the frozen state was investigated both numerically and experimentally for various heat loads and input locations. A high temperature sodium/stainless steel heat pipe with multiple heat sources and sinks was fabricated, processed, and tested. A numerical simulation of the transient heat pipe performance including the vapor region, wick structure, and the heat pipe wall is given. Furthermore, experimental and numerical analyses of several operating parameters of a low-temperature copper-water heat pipe under uniform circumferential heating and block heating has been performed. Finally, a numerical analysis of transient heat pipe performance including nonconventional heat pipes with nonuniform heat distributions is presented. Numerical calculations were then made for a leading edge heat pipe with localized high heat fluxes.

  2. High-cost, high-capacity backbone for global brain communication.

    Science.gov (United States)

    van den Heuvel, Martijn P; Kahn, René S; Goñi, Joaquín; Sporns, Olaf

    2012-07-10

    Network studies of human brain structural connectivity have identified a specific set of brain regions that are both highly connected and highly central. Recent analyses have shown that these putative hub regions are mutually and densely interconnected, forming a "rich club" within the human brain. Here we show that the set of pathways linking rich club regions forms a central high-cost, high-capacity backbone for global brain communication. Diffusion tensor imaging (DTI) data of two sets of 40 healthy subjects were used to map structural brain networks. The contributions to network cost and communication capacity of global cortico-cortical connections were assessed through measures of their topology and spatial embedding. Rich club connections were found to be more costly than predicted by their density alone and accounted for 40% of the total communication cost. Furthermore, 69% of all minimally short paths between node pairs were found to travel through the rich club and a large proportion of these communication paths consisted of ordered sequences of edges ("path motifs") that first fed into, then traversed, and finally exited the rich club, while passing through nodes of increasing and then decreasing degree. The prevalence of short paths that follow such ordered degree sequences suggests that neural communication might take advantage of strategies for dynamic routing of information between brain regions, with an important role for a highly central rich club. Taken together, our results show that rich club connections make an important contribution to interregional signal traffic, forming a central high-cost, high-capacity backbone for global brain communication.

  3. Fabrications of High-Capacity Alpha-Ni(OH2

    Directory of Open Access Journals (Sweden)

    Kwo-Hsiung Young

    2017-03-01

    Full Text Available Three different methods were used to produce α-Ni(OH2 with higher discharge capacities than the conventional β-Ni(OH2, specifically a batch process of co-precipitation, a continuous process of co-precipitation with a phase transformation step (initial cycling, and an overcharge at low temperature. All three methods can produce α-Ni(OH2 or α/β mixed-Ni(OH2 with capacities higher than that of conventional β-Ni(OH2 and a stable cycle performance. The second method produces a special core–shell β-Ni(OH2/α-Ni(OH2 structure with an excellent cycle stability in the flooded half-cell configuration, is innovative and also already mass-production ready. The core–shell structure has been investigated by both scanning and transmission electron microscopies. The shell portion of the particle is composed of α-Ni(OH2 nano-crystals embedded in a β-Ni(OH2 matrix, which helps to reduce the stress originating from the lattice expansion in the β-α transformation. A review on the research regarding α-Ni(OH2 is also included in the paper.

  4. HEAT: High accuracy extrapolated ab initio thermochemistry.

    Science.gov (United States)

    Tajti, Attila; Szalay, Péter G; Császár, Attila G; Kállay, Mihály; Gauss, Jürgen; Valeev, Edward F; Flowers, Bradley A; Vázquez, Juana; Stanton, John F

    2004-12-15

    A theoretical model chemistry designed to achieve high accuracy for enthalpies of formation of atoms and small molecules is described. This approach is entirely independent of experimental data and contains no empirical scaling factors, and includes a treatment of electron correlation up to the full coupled-cluster singles, doubles, triples and quadruples approach. Energies are further augmented by anharmonic zero-point vibrational energies, a scalar relativistic correction, first-order spin-orbit coupling, and the diagonal Born-Oppenheimer correction. The accuracy of the approach is assessed by several means. Enthalpies of formation (at 0 K) calculated for a test suite of 31 atoms and molecules via direct calculation of the corresponding elemental formation reactions are within 1 kJ mol(-1) to experiment in all cases. Given the quite different bonding environments in the product and reactant sides of these reactions, the results strongly indicate that even greater accuracy may be expected in reactions that preserve (either exactly or approximately) the number and types of chemical bonds. (c) 2004 American Institute of Physics

  5. The Expression of Carnosine and Its Effect on the Antioxidant Capacity of Muscle in Finishing Pigs Exposed to Constant Heat Stress

    Directory of Open Access Journals (Sweden)

    Peige Yang

    2014-12-01

    Full Text Available The objective of this study was to assess the effects of constant high ambient temperatures on meat quality, antioxidant capacity, and carnosine expression in longissimus dorsi muscle of finishing pigs. Castrated 24 male DLY (crossbreeds between Landrace×Yorkshire sows and Duroc boars pigs were allocated to one of three treatments: constant ambient temperature at 22°C and ad libitum feeding (CON, n = 8; constant high ambient temperature at 30°C and ad libitum feeding (H30, n = 8; and constant ambient temperature at 22°C and pair-fed with H30 (PF, n = 8. Meat quality, malondialdehyde (MDA content, antioxidant capacity, carnosine content, and carnosine synthetase (CARNS1 mRNA expression in longissimus dorsi muscle were measured after three weeks. The results revealed that H30 had lower pH24 h, redness at 45 min, and yellowness at 24 h post-mortem (p<0.05, and higher drip loss at 48 h and lightness at 24 h post-mortem (p<0.01. Constant heat stress disrupted the pro-oxidant/antioxidant balance in longissimus dorsi muscle with higher MDA content (p<0.01 and lower antioxidant capacity (p<0.01. Carnosine content and CARNS1 mRNA expression in longissimus dorsi muscle of H30 pigs were significantly decreased (p<0.01 after three weeks at 30°C. In conclusion, constant high ambient temperatures affect meat quality and antioxidant capacity negatively, and the reduction of muscle carnosine content is one of the probable reasons.

  6. Unbalanced heat isolation in high-frequency electrothermics of polymers

    Directory of Open Access Journals (Sweden)

    A. V. Livshits

    2014-01-01

    Full Text Available The polymeric materials are widely applied in many industries because they have a number of advantages, which allow their use instead of traditional materials. Nevertheless, the issues of manufacturing products from polymeric materials and their applications are insufficiently studied. The same can be said about high-frequency (HF electrothermics of polymers. Therefore, mathematical simulation of electrothermic processes is of interest both in terms of science and in terms of applications.Traditionally, the technological scheme with one insulator made of cardboard is used to implement the HF heating processes for welding of polymers without analyzing their insulating properties. For welding of polymer parts with various thickness it is interesting to consider the scheme with two heat insulators in the form of five-layer plate, including electrodes, insulators, and processed material. As a result of the conducted research activities the article presents a mathematical model in the form of a system of differential equations of unsteady heat conductivity taking into account internal sources of heat with appropriate boundary conditions, and software to implement it.The software that implements a mathematical model enables to study the mutual influence between the geometrical and electro-physical parameters of technological system of HF heating of the thermoplastics. From the calculations presented in numerical and graphic form the following areas of heating polymer are identified: uniform heating, regional zones of thermal influence of insulators.The article presents the research results of influence of heat insulators with different thickness on the distribution of thermoplastics temperature field. It is determined that the zone of maximum value of heating polymer can be displaced by modifying the parameters of insulating layers, thereby improving the welding quality of polymeric items.According to research results, we can conclude that there is a

  7. Experiments on Long-Haul High-Capacity Transmission Systems

    Science.gov (United States)

    Bosco, Gabriella; Matera, Francesco; Ennser, Karin; Ibsen, Morten; Marazzi, Lucia; Parmigiani, Francesca; Petropoulos, Periklis; Poggiolini, Pierluigi; Tabacchiera, Marco; Zannin, Marcelo

    Progress in optical communications has been one of the key factors for the enormous growth of the ICT sector, and, in particular, of the Internet phenomenon. Such a progress has been driven by experimental successes that have been obtained in the last three decades in several laboratories all over the world, and we have witnessed a fantastic challenge among such labs to reach record targets such as maximum bit rate, maximum propagation distance, higher performance, maximum efficiency, and, recently, minimum energy consumption. The search for the maximum bit rate × distance was based on the principle of infinite bandwidth of the optical fiber that let us to imagine transmission of enormous capacities over transoceanic distances, especially after the invention of the optical amplifier.

  8. Economic viability of transmission capacity expansion at high wind penetrations

    DEFF Research Database (Denmark)

    Østergaard, Poul Alberg

    2005-01-01

    With growing wind power penetrations in many countries, grid and system integration becomes more and more important issues. This is particularly the case in countries or regions with good wind resources as well as substantial installed wind power capacity as found in e.g. Northern Europe. At 20......% penetration in Western Denmark, the issue is pertinent here in relation to future plans of further expansion which is planned in accordance with the Danish Government’s climate change mitigation initiatives. This paper analyses the potential economic benefit of selling excess electricity production...... investments and analyses of the Nord Pool price variations. The analyses are done for varying degrees of wind power penetrations ranging from 20% of the West Danish electricity demand up to 100% of the demand. The analyses demonstrate, that while there is an economic potential for some expansion in some years...

  9. High capacity adsorption media and method of producing

    Science.gov (United States)

    Tranter, Troy J.; Mann, Nicholas R.; Todd, Terry A.; Herbst, Ronald S.

    2010-10-05

    A method of producing an adsorption medium to remove at least one constituent from a feed stream. The method comprises dissolving and/or suspending at least one metal compound in a solvent to form a metal solution, dissolving polyacrylonitrile into the metal solution to form a PAN-metal solution, and depositing the PAN-metal solution into a quenching bath to produce the adsorption medium. The at least one constituent, such as arsenic, selenium, or antimony, is removed from the feed stream by passing the feed stream through the adsorption medium. An adsorption medium having an increased metal loading and increased capacity for arresting the at least one constituent to be removed is also disclosed. The adsorption medium includes a polyacrylonitrile matrix and at least one metal hydroxide incorporated into the polyacrylonitrile matrix.

  10. Development of High Efficiency Carbon Dioxide Commercial Heat Pump Water Heater

    Energy Technology Data Exchange (ETDEWEB)

    Michael PETERSEN; Chad D. BOWERS; Stefan ELBEL; Pega HRNJAK

    2012-07-01

    Although heat pump water heaters are today widely accepted in both Japan and Europe, where energy costs are high and government incentives for their use exist, acceptance of such products in the US has been limited. While this trend is slowly changing with the introduction of heat pump water heaters into the residential market, but acceptance remains low in the commercial sector. The objective of the presented work is the development of a high efficiency R744 heat pump water heater for commercial applications with effective utilization of the cooling capability for air conditioning and/or refrigeration. The ultimate goal is to achieve total system COP of up to 8. This unit will be targeted at commercial use where some cooling load is typically needed year round, such as restaurants, hotels, nursing homes, and hospitals. This paper presents the performance results from the development of four R744 commercial heat pump water heater packages of approximately 35 kW and comparison to a commercially available baseline R134a unit of the same capacity and footprint. In addition, the influences of an internal heat exchanger and an enhanced evaporator on the system performance are described and recommendations are made for further improvements of the R744 system.

  11. Evaluation of selected advanced heat exchangers for waste heat recuperation of high temperature streams

    Science.gov (United States)

    Bliem, C. J.; Kochan, R.; Mittl, J. C.; Piscitella, R. R.; Schafer, J.; Synder, A.; Wiggins, D.; Zabriskie, J. N.

    1984-02-01

    The design, functional and cost requirements for high-temperature, heat recovery systems (recuperators) and describes the state-of-the-art systems, emerging industrial technologies and new concepts developed by EG and G Idaho, Inc. are discussed. All systems/concepts are then evaluated and compared with respect to corrosion/durability, fouling, performance, operation and maintenance, and economics.

  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. VTX HyHeat Project

    Data.gov (United States)

    National Aeronautics and Space Administration — In this project Orbital Technologies Corporation (ORBITEC) will utilize its unique vortex propulsion technology to develop a high-capacity heating system to heat...

  14. Break in the Heat Capacity Change at 303 K for Complex Binding of Netropsin to AATT Containing Hairpin DNA Constructs

    Science.gov (United States)

    Freyer, Matthew W.; Buscaglia, Robert; Hollingsworth, Amy; Ramos, Joseph; Blynn, Meredith; Pratt, Rachael; Wilson, W. David; Lewis, Edwin A.

    2007-01-01

    Studies performed in our laboratory demonstrated the formation of two thermodynamically distinct complexes on binding of netropsin to a number of hairpin-forming DNA sequences containing AATT-binding regions. These two complexes were proposed to differ only by a bridging water molecule between the drug and the DNA in the lower affinity complex. A temperature-dependent isothermal titration calorimetry (ITC)-binding study was performed using one of these constructs (a 20-mer hairpin of sequence 5′-CGAATTCGTCTCCGAATTCG) and netropsin. This study demonstrated a break in the heat capacity change for the formation of the complex containing the bridging water molecule at ∼303 K. In the plot of the binding enthalpy change versus temperature, the slope (ΔCp) was −0.67 kcal mol−1 K−1 steeper after the break at 303 K. Because of the relatively low melting temperature of the 20-mer hairpin (341 K (68°C)), the enthalpy change for complex formation might have included some energy of refolding of the partially denatured hairpin, giving the suggestion of a larger ΔCp. Studies done on the binding of netropsin to similar constructs, a 24-mer and a 28-mer, with added GC basepairs in the hairpin stem to increase thermal stability, exhibit the same nonlinearity in ΔCp over the temperature range of from 275 to 333 K. The slopes (ΔCp) were −0.69 and −0.64 kcal mol−1 K−1 steeper after 303 K for the 24-mer and 28-mer, respectively. This observation strengthens the argument regarding the presence of a bridging water molecule in the lower affinity netropsin/DNA complex. The ΔCp data seem to infer that because the break in the heat capacity change function for the lower affinity binding occurs at the isoequilibrium temperature for water, water may be included or trapped in the complex. The fact that this break does not occur in the heat capacity change function for formation of the higher affinity complex can similarly be taken as evidence that water is not included in

  15. Heating capacity of rebound shortwave diathermy and moist hot packs at superficial depths.

    Science.gov (United States)

    Hawkes, Amanda R; Draper, David O; Johnson, A Wayne; Diede, Mike T; Rigby, Justin H

    2013-01-01

    The effectiveness of a new continuous diathermy unit, ReBound, as a heating modality is unknown. To compare the effects of ReBound diathermy with silicate-gel moist hot packs on tissue temperature in the human triceps surae muscle. Crossover study. University research laboratory. A total of 12 healthy, college-aged volunteers (4 men, 8 women; age = 22.2 ± 2.25 years, calf subcutaneous fat thickness = 7.2 ± 1.9 mm). On 2 different days, 1 of 2 modalities (ReBound diathermy, silicate-gel moist hot pack) was applied to the triceps surae muscle of each participant for 30 minutes. After 30 minutes, the modality was removed, and temperature decay was recorded for 20 minutes. Medial triceps surae intramuscular tissue temperature at a depth of 1 cm was measured using an implantable thermocouple inserted horizontally into the muscle. Measurements were taken every 5 minutes during the 30-minute treatment and every minute during the 20-minute temperature decay, for a total of 50 minutes. Treatment was analyzed through a 2 × 7 mixed-model analysis of variance with repeated measures. Temperature decay was analyzed through a 2 × 21 mixed-model analysis of variance with repeated measures. During the 30-minute application, tissue temperatures at a depth of 1 cm increased more with the ReBound diathermy than with the moist hot pack (F6,66 = 7.14, P diathermy and moist hot packs increased tissue temperatures 3.69°C ± 1.50°C and 2.82°C ± 0.90°C, respectively, from baseline. Throughout the temperature decay, ReBound diathermy produced a greater rate of heat dissipation than the moist hot pack (F20,222 = 4.42, P diathermy increased tissue temperature to moderate levels, which were greater than the levels reached with moist hot packs.

  16. Heat Transfer in High-Temperature Fibrous Insulation

    Science.gov (United States)

    Daryabeigi, Kamran

    2002-01-01

    The combined radiation/conduction heat transfer in high-porosity, high-temperature fibrous insulations was investigated experimentally and numerically. The effective thermal conductivity of fibrous insulation samples was measured over the temperature range of 300-1300 K and environmental pressure range of 1.33 x 10(exp -5)-101.32 kPa. The fibrous insulation samples tested had nominal densities of 24, 48, and 72 kilograms per cubic meter and thicknesses of 13.3, 26.6 and 39.9 millimeters. Seven samples were tested such that the applied heat flux vector was aligned with local gravity vector to eliminate natural convection as a mode of heat transfer. Two samples were tested with reverse orientation to investigate natural convection effects. It was determined that for the fibrous insulation densities and thicknesses investigated no heat transfer takes place through natural convection. A finite volume numerical model was developed to solve the governing combined radiation and conduction heat transfer equations. Various methods of modeling the gas/solid conduction interaction in fibrous insulations were investigated. The radiation heat transfer was modeled using the modified two-flux approximation assuming anisotropic scattering and gray medium. A genetic-algorithm based parameter estimation technique was utilized with this model to determine the relevant radiative properties of the fibrous insulation over the temperature range of 300-1300 K. The parameter estimation was performed by least square minimization of the difference between measured and predicted values of effective thermal conductivity at a density of 24 kilograms per cubic meters and at nominal pressures of 1.33 x 10(exp -4) and 99.98 kPa. The numerical model was validated by comparison with steady-state effective thermal conductivity measurements at other densities and pressures. The numerical model was also validated by comparison with a transient thermal test simulating reentry aerodynamic heating

  17. Experiences and challenges running CERN's high capacity tape archive

    CERN Document Server

    Cancio, Germ; Kruse, Daniele Francesco; Leduc, Julien; Cano, Eric; Murray, Steven

    2015-01-01

    CERN's tape-based archive system has collected over 70 Petabytes of data during the first run of the LHC. The Long Shutdown is being used for migrating the complete 100 Petabytes data archive to higher-density tape media. During LHC Run 2, the archive will have to cope with yearly growth rates of up to 40-50 Petabytes. In this contribution, we describe the scalable setup for coping with the storage and long-term archival of such massive data amounts. We also review the challenges resulting and mechanisms devised for measuring and enhancing availability and reliability, as well as ensuring the long-term integrity and bit-level preservation of the complete data repository. The procedures and tools for the proactive and efficient operation of the tape infrastructure are described, including the features developed for automated problem detection, identification and notification. Finally, we present an outlook in terms of future capacity requirements growth and how it matches the expected tape technology evolution...

  18. Experiences and challenges running CERN's high capacity tape archive

    Science.gov (United States)

    Cancio, Germán; Bahyl, Vladimír; Kruse, Daniele Francesco; Leduc, Julien; Cano, Eric; Murray, Steven

    2015-12-01

    CERN's tape-based archive system has collected over 70 Petabytes of data during the first run of the LHC. The Long Shutdown is being used for migrating the complete 100 Petabytes data archive to higher-density tape media. During LHC Run 2, the archive will have to cope with yearly growth rates of up to 40-50 Petabytes. In this contribution, we describe the scalable setup for coping with the storage and long-term archival of such massive data amounts. We also review the challenges resulting and mechanisms devised for measuring and enhancing availability and reliability, as well as ensuring the long-term integrity and bit-level preservation of the complete data repository. The procedures and tools for the proactive and efficient operation of the tape infrastructure are described, including the features developed for automated problem detection, identification and notification. Finally, we present an outlook in terms of future capacity requirements growth and how it matches the expected tape technology evolution.

  19. 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.

  20. First principles based group additive values for the gas phase standard entropy and heat capacity of hydrocarbons and hydrocarbon radicals.

    Science.gov (United States)

    Sabbe, Maarten K; De Vleeschouwer, Freija; Reyniers, Marie-Françoise; Waroquier, Michel; Marin, Guy B

    2008-11-27

    In this work a complete and consistent set of 95 Benson group additive values (GAVs) for standard entropies S(o) and heat capacities C(p)(o) of hydrocarbons and hydrocarbon radicals is presented. These GAVs include 46 groups, among which 25 radical groups, which, to the best of our knowledge, have not been reported before. The GAVs have been determined from a set of B3LYP/6-311G(d,p) ideal gas statistical thermodynamics values for 265 species, consistently with previously reported GAVs for standard enthalpies of formation. One-dimensional hindered rotor corrections for all internal rotations are included. The computational methodology has been compared to experimental entropies (298 K) for 39 species, with a mean absolute deviation (MAD) between experiment and calculation of 1.2 J mol(-1) K(-1), and to 46 experimental heat capacities (298 K) with a resulting MAD = 1.8 J mol(-1) K(-1). The constructed database allowed evaluation of corrections on S(o) and C(p)(o) for non-nearest-neighbor effects, which have not been determined previously. The group additive model predicts the S(o) and C(p)(o) within approximately 5 J mol(-1) K(-1) of the ab initio values for 11 of the 14 molecules of the test set, corresponding to an acceptable maximal deviation of a factor of 1.6 on the equilibrium coefficient. The obtained GAVs can be applied for the prediction of S(o) and C(p)(o) for a wide range of hydrocarbons and hydrocarbon radicals. The constructed database also allowed determination of a large set of hydrogen bond increments, which can be useful for the prediction of radical thermochemistry.

  1. Electronic miniband structure, heat capacity and magnetic susceptibility of monolayer and bilayer silicene in TI, VSPM and BI regimes

    Energy Technology Data Exchange (ETDEWEB)

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

    2017-04-11

    In the current work, we theoretically study the electronic band structure (EBS), electronic heat capacity (EHC) and magnetic susceptibility (MS) of three structures including monolayer, AA-stacked and AB-stacked bilayer silicene based on the Kane–Mele Hamiltonian model and Green's function method. The particular attention of this study is paid to the effect of external electric field on the aforementioned physical properties. By variation of the electric field, three phases are found: Topological insulator (TI), valley–spin polarized metal (VSPM) and band insulator (BI). Marvellously, its electronic minibands show that the spin-up contribution of charge carriers with lowest energy bands behaves like relativistic Dirac fermions with linear (parabolic) energy dispersions in monolayer (bilayer) case near the Dirac points. An insightful analysis shows that the maximum and minimum value of EHC peak appear for (AA) AB-stacked bilayer and monolayer silicene in TI (BI) regime while in MS curves appear for (AB) AA-stacked bilayer and monolayer lattices in TI (BI) regime, respectively. Moreover, we have observed a phase transition from antiferromagnetic to ferromagnetic and paramagnetic in the monolayer and bilayer structures in the VSPM regime based on the MS findings, respectively. - Highlights: • Comparison of electronic miniband structure of monolayer and bilayer silicene by using the Kane–Mele model and Green's function technique. • Investigation and comparison the electronic contribution of heat capacity for different configurations of silicene structures. • Observation of phase transition from antiferromagnetic to ferromagnetic and paramagnetic phase in the monolayer and bilayer cases, respectively.

  2. 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.

  3. Selection of local extremophile lactic acid bacteria with high capacity ...

    African Journals Online (AJOL)

    This study is related to the isolation and identification of strains of local thermophilic lactic acid bacteria belonging to the species, Streptococcus thermophilus and Lactobacillus bulgaricus. These bacteria can exist under extreme conditions of the digestive tract (acidity and high concentration of bile salts) and have a high ...

  4. High throughput assay for evaluation of reactive carbonyl scavenging capacity

    Directory of Open Access Journals (Sweden)

    N. Vidal

    2014-01-01

    Full Text Available Many carbonyl species from either lipid peroxidation or glycoxidation are extremely reactive and can disrupt the function of proteins and enzymes. 4-hydroxynonenal and methylglyoxal are the most abundant and toxic lipid-derived reactive carbonyl species. The presence of these toxics leads to carbonyl stress and cause a significant amount of macromolecular damages in several diseases. Much evidence indicates trapping of reactive carbonyl intermediates may be a useful strategy for inhibiting or decreasing carbonyl stress-associated pathologies. There is no rapid and convenient analytical method available for the assessment of direct carbonyl scavenging capacity, and a very limited number of carbonyl scavengers have been identified to date, their therapeutic potential being highlighted only recently. In this context, we have developed a new and rapid sensitive fluorimetric method for the assessment of reactive carbonyl scavengers without involvement glycoxidation systems. Efficacy of various thiol- and non-thiol-carbonyl scavenger pharmacophores was tested both using this screening assay adapted to 96-well microplates and in cultured cells. The scavenging effects on the formation of Advanced Glycation End-product of Bovine Serum Albumin formed with methylglyoxal, 4-hydroxynonenal and glucose-glycated as molecular models were also examined. Low molecular mass thiols with an α-amino-β-mercaptoethane structure showed the highest degree of inhibitory activity toward both α,β-unsaturated aldehydes and dicarbonyls. Cysteine and cysteamine have the best scavenging ability toward methylglyoxal. WR-1065 which is currently approved for clinical use as a protective agent against radiation and renal toxicity was identified as the best inhibitor of 4-hydroxynonenal.

  5. Development of a high capacity longwall conveyor. Final technical report

    Energy Technology Data Exchange (ETDEWEB)

    Sparks, C

    1982-05-01

    The objectives of this program were to develop, fabricate, and demonstrate a longwall conveying system capable of transporting coal at a rate of 9000 tons/day (1000 tons/hr) and capable of accommodating a surge rate of 20 tons/min. The equipment was required to have the structural durability to perform with an operating availability of 90%. A review of available literature and discussions with longwall operators identified the problem areas of conveyor design that required attention. The conveyor under this contract was designed and fabricated with special attention given to these areas, and also to be easily maintainable. The design utilized twin 300 hp drives and twin inboard 26-mm chain at 270 ft/min; predictions of capacity and reliability based on the design indicating that it would satisfy the program requirements. Conveyor components were critically tested and the complete conveyor was surface-tested, the results verifying the design specifications. In addition, an instrumentation system was developed with analysis by computer techniques to monitor the performance of the conveyor. The conveyor was installed at a selected mine site, and it was the intention to monitor its performance over the entire longwall panel. Monitoring of the conveyor performance was conducted over approximately one-third of the longwall panel, at which point further effort was suspended. However, during the monitored period, data collected from various sources showed the conveyor to have exhibited its capability of transporting coal at the desired rate, and also to have conformed to the program requirements of reliability and availability.

  6. Global anthropogenic heat flux database with high spatial resolution

    Science.gov (United States)

    Dong, Y.; Varquez, A. C. G.; Kanda, M.

    2017-02-01

    This study developed a top-down method for estimating global anthropogenic heat emission (AHE), with a high spatial resolution of 30 arc-seconds and temporal resolution of 1 h. Annual average AHE was derived from human metabolic heating and primary energy consumption, which was further divided into three components based on consumer sector. The first and second components were heat loss and heat emissions from industrial sectors equally distributed throughout the country and populated areas, respectively. The third component comprised the sum of emissions from commercial, residential, and transportation sectors (CRT). Bulk AHE from the CRT was proportionally distributed using a global population dataset, with a radiance-calibrated nighttime lights adjustment. An empirical function to estimate monthly fluctuations of AHE based on gridded monthly temperatures was derived from various Japanese and American city measurements. Finally, an AHE database with a global coverage was constructed for the year 2013. Comparisons between our proposed AHE and other existing datasets revealed that the problem of overestimation of AHE intensity in previous top-down models was mitigated by the separation of energy consumption sectors; furthermore, the problem of AHE underestimation at central urban areas was solved by the nighttime lights adjustment. A strong agreement in the monthly profiles of AHE between our database and other bottom-up datasets further proved the validity of the current methodology. Investigations of AHE for the 29 largest urban agglomerations globally highlighted that the share of heat emissions from CRT sectors to the total AHE at the city level was 40-95%; whereas that of metabolic heating varied with the city's level of development by a range of 2-60%. A negative correlation between gross domestic product (GDP) and the share of metabolic heating to a city's total AHE was found. Globally, peak AHE values were found to occur between December and February, while

  7. Stagnation Region Heat Transfer Augmentation at Very High Turbulence Levels

    Energy Technology Data Exchange (ETDEWEB)

    Ames, Forrest [University of North Dakota; Kingery, Joseph E. [University of North Dakota

    2015-06-17

    A database for stagnation region heat transfer has been extended to include heat transfer measurements acquired downstream from a new high intensity turbulence generator. This work was motivated by gas turbine industry heat transfer designers who deal with heat transfer environments with increasing Reynolds numbers and very high turbulence levels. The new mock aero-combustor turbulence generator produces turbulence levels which average 17.4%, which is 37% higher than the older turbulence generator. The increased level of turbulence is caused by the reduced contraction ratio from the liner to the exit. Heat transfer measurements were acquired on two large cylindrical leading edge test surfaces having a four to one range in leading edge diameter (40.64 cm and 10.16 cm). Gandvarapu and Ames [1] previously acquired heat transfer measurements for six turbulence conditions including three grid conditions, two lower turbulence aero-combustor conditions, and a low turbulence condition. The data are documented and tabulated for an eight to one range in Reynolds numbers for each test surface with Reynolds numbers ranging from 62,500 to 500,000 for the large leading edge and 15,625 to 125,000 for the smaller leading edge. The data show augmentation levels of up to 136% in the stagnation region for the large leading edge. This heat transfer rate is an increase over the previous aero-combustor turbulence generator which had augmentation levels up to 110%. Note, the rate of increase in heat transfer augmentation decreases for the large cylindrical leading edge inferring only a limited level of turbulence intensification in the stagnation region. The smaller cylindrical leading edge shows more consistency with earlier stagnation region heat transfer results correlated on the TRL (Turbulence, Reynolds number, Length scale) parameter. The downstream regions of both test surfaces continue to accelerate the flow but at a much lower rate than the leading edge. Bypass transition occurs

  8. Heat capacities and volumetric changes in the glass transition range: a constitutive approach based on the standard linear solid

    Science.gov (United States)

    Lion, Alexander; Mittermeier, Christoph; Johlitz, Michael

    2017-09-01

    A novel approach to represent the glass transition is proposed. It is based on a physically motivated extension of the linear viscoelastic Poynting-Thomson model. In addition to a temperature-dependent damping element and two linear springs, two thermal strain elements are introduced. In order to take the process dependence of the specific heat into account and to model its characteristic behaviour below and above the glass transition, the Helmholtz free energy contains an additional contribution which depends on the temperature history and on the current temperature. The model describes the process-dependent volumetric and caloric behaviour of glass-forming materials, and defines a functional relationship between pressure, volumetric strain, and temperature. If a model for the isochoric part of the material behaviour is already available, for example a model of finite viscoelasticity, the caloric and volumetric behaviour can be represented with the current approach. The proposed model allows computing the isobaric and isochoric heat capacities in closed form. The difference c_p -c_v is process-dependent and tends towards the classical expression in the glassy and equilibrium ranges. Simulations and theoretical studies demonstrate the physical significance of the model.

  9. Thermal barrier coatings (TBC's) for high heat flux thrust chambers

    Science.gov (United States)

    Bradley, Christopher M.

    The last 30 years materials engineers have been under continual pressure to develop materials with a greater temperature potential or to produce configurations that can be effectively cooled or otherwise protected at elevated temperature conditions. Turbines and thrust chambers produce some of the harshest service conditions for materials which lead to the challenges engineers face in order to increase the efficiencies of current technologies due to the energy crisis that the world is facing. The key tasks for the future of gas turbines are to increase overall efficiencies to meet energy demands of a growing world population and reduce the harmful emissions to protect the environment. Airfoils or blades tend to be the limiting factor when it comes to the performance of the turbine because of their complex design making them difficult to cool as well as limitations of their thermal properties. Key tasks for space transportation it to lower costs while increasing operational efficiency and reliability of our space launchers. The important factor to take into consideration is the rocket nozzle design. The design of the rocket nozzle or thrust chamber has to take into account many constraints including external loads, heat transfer, transients, and the fluid dynamics of expanded hot gases. Turbine engines can have increased efficiencies if the inlet temperature for combustion is higher, increased compressor capacity and lighter weight materials. In order to push for higher temperatures, engineers need to come up with a way to compensate for increased temperatures because material systems that are being used are either at or near their useful properties limit. Before thermal barrier coatings were applied to hot-section components, material alloy systems were able to withstand the service conditions necessary. But, with the increased demand for performance, higher temperatures and pressures have become too much for those alloy systems. Controlled chemistry of hot

  10. Experimental Equipment for Damping Capacity Analyze of High or Low Internal Friction Metallic Materials

    Science.gov (United States)

    Gârnet, I. A.; Stanciu, S.; Hopulele, I.; Zaharia, M. G.; Cimpoesu, N.; Chicet, D. L.; Crăciun, R. C.

    2017-06-01

    An experimental equipment, type torsion pendulum was made in laboratory in order to analyze the damping capacity of metallic materials. The scheme of the equipment is presented, 2D and 3D visions at real scale. The equipment functioning (mechanical and electrical part) and principles are presented. In this article we present some preliminary experimental results obtained on different materials (aluminium, steel etc.) using two different methods for registration the outputs (one based on optoelectronic device with Arduino acquisition board and second on video analyze (cinematic review: video to jpeg) of the damped motion of the lead pendulum). Steel materials were with shoot penning surface modification with and without heat treatment in order to establish the heat treatment influence on the damping capacity property.

  11. Predicting high harmonic ion cyclotron heating efficiency in Tokamak plasmas.

    Science.gov (United States)

    Green, D L; Berry, L A; Chen, G; Ryan, P M; Canik, J M; Jaeger, E F

    2011-09-30

    Observations of improved radio frequency (rf) heating efficiency in ITER relevant high-confinement (H-)mode plasmas on the National Spherical Tokamak Experiment are investigated by whole-device linear simulation. The steady-state rf electric field is calculated for various antenna spectra and the results examined for characteristics that correlate with observations of improved or reduced rf heating efficiency. We find that launching toroidal wave numbers that give fast-wave propagation in the scrape-off plasma excites large amplitude (∼kV m(-1)) coaxial standing modes between the confined plasma density pedestal and conducting vessel wall. Qualitative comparison with measurements of the stored plasma energy suggests that these modes are a probable cause of degraded heating efficiency.

  12. O+ and H+ ion heat fluxes at high altitudes and high latitudes

    Directory of Open Access Journals (Sweden)

    I. A. Barghouthi

    2014-08-01

    Full Text Available Higher order moments, e.g., perpendicular and parallel heat fluxes, are related to non-Maxwellian plasma distributions. Such distributions are common when the plasma environment is not collision dominated. In the polar wind and auroral regions, the ion outflow is collisionless at altitudes above about 1.2 RE geocentric. In these regions wave–particle interaction is the primary acceleration mechanism of outflowing ionospheric origin ions. We present the altitude profiles of actual and "thermalized" heat fluxes for major ion species in the collisionless region by using the Barghouthi model. By comparing the actual and "thermalized" heat fluxes, we can see whether the heat flux corresponds to a small perturbation of an approximately bi-Maxwellian distribution (actual heat flux is small compared to "thermalized" heat flux, or whether it represents a significant deviation (actual heat flux equal or larger than "thermalized" heat flux. The model takes into account ion heating due to wave–particle interactions as well as the effects of gravity, ambipolar electric field, and divergence of geomagnetic field lines. In the discussion of the ion heat fluxes, we find that (1 the role of the ions located in the energetic tail of the ion velocity distribution function is very significant and has to be taken into consideration when modeling the ion heat flux at high altitudes and high latitudes; (2 at times the parallel and perpendicular heat fluxes have different signs at the same altitude. This indicates that the parallel and perpendicular parts of the ion energy are being transported in opposite directions. This behavior is the result of many competing processes; (3 we identify altitude regions where the actual heat flux is small as compared to the "thermalized" heat flux. In such regions we expect transport equation solutions based on perturbations of bi-Maxwellian distributions to be applicable. This is true for large altitude intervals for protons

  13. The electronic heat capacity of YBa{sub 2}Cu{sub 3}O{sub 7−δ} superconductor

    Energy Technology Data Exchange (ETDEWEB)

    Singh, Anu, E-mail: anuiiser@gmail.com; Singh, Hempal; Indu, B. D., E-mail: drbdindu@gmail.com [Department of Physics, Indian Institute of Technology Roorkee 247667, Uttarakhand (India)

    2016-07-15

    The contributions due to the point defects or disorder and anharmonicities which play deterministic role in the understanding of electronic heat capacity (EHC) of high temperature superconductors (HTS) have been investigated via electron density of states (EDOS) approach on the basis of quantum dynamical many body theory. The evaluation of EDOS has been carried out with the help of most versatile method of double time temperature dependent electron Green’s functions (GF) via a Hamiltonian (non BCS type) which includes the effects of electrons, phonons, defects, anharmonicity, and electron-phonon interactions which enables to account the effects of cubic anharmonicity besides with both the force constant changes and mass difference caused by the impurities in developing the results for EDOS and EHC. The new results reveal some striking features of EHC of HTS.

  14. The heat capacity and density of solutions of barium and tetrabutylammonium iodides in N-methylpyrrolidone at 298.15 K

    Science.gov (United States)

    Novikov, A. N.; Lenina, O. F.; Vasilev, V. A.

    2009-03-01

    The heat capacity and density of solutions of barium and tetrabutylammonium iodides in N-methylpyrrolidone (MP) were studied at 298.15 K by calorimetry and densimetry. The standard partial molar heat capacities and volumes ( overline {C_{p^2 }^ circ } and overline {V_2^ circ } ) of the electrolytes in MP were calculated. The standard heat capacities overline {C_{pi}^ circ } and volumes overline {V_i^ circ } of the Ba2+ and (C4H9)4N+ ions in solution in MP at 298.15 K were determined. With the tetrabutylammonium ion, these values were in agreement with those calculated on the basis of the tetraphenylarsonium-tetraphenyl borate and tetraphenylphosphonium-tetraphenyl borate assumptions. The results are discussed in relation to the special features of solvation in solutions of the salts studied.

  15. High-Capacity Short-Range Optical Communication Links

    DEFF Research Database (Denmark)

    Tatarczak, Anna

    Over the last decade, we have observed a tremendous spread of end-user mobile devices. The user base of a mobile application can grow or shrink by millions per day. This situation creates a pressing need for highly scalable server infrastructure; a need nowadays satisfied through cloud computing...... offered by data centers. As the popularity of cloud computing soars, the demand for high-speed, short-range data center links grows. Vertical cavity surface emitting lasers (VCSEL) and multimode fibers (MMF) prove especially well-suited for such scenarios. VCSELs have high modulation bandwidths......, we achieve 10 Gbps over 400 m and then conrm the approach in an optimized system at 25 Gbps over 300 m. The techniques described in this thesis leverage additional degrees of freedom to better utilize the available resources of short-range links. The proposed schemes enable higher speeds and longer...

  16. High Intrinsic Aerobic Capacity Protects against Ethanol-Induced Hepatic Injury and Metabolic Dysfunction: Study Using High Capacity Runner Rat Model.

    Science.gov (United States)

    Szary, Nicholas; Rector, R Scott; Uptergrove, Grace M; Ridenhour, Suzanne E; Shukla, Shivendra D; Thyfault, John P; Koch, Lauren G; Britton, Steven L; Ibdah, Jamal A

    2015-11-20

    Rats artificially selected over several generations for high intrinsic endurance/aerobic capacity resulting in high capacity runners (HCR) has been developed to study the links between high aerobic fitness and protection from metabolic diseases (Wisloff et al., Science, 2005). We have previously shown that the HCR strain have elevated hepatic mitochondrial content and oxidative capacity. In this study, we tested if the elevated hepatic mitochondrial content in the HCR rat would provide "metabolic protection" from chronic ethanol-induced hepatic steatosis and injury. The Leiber-Decarli liquid diet with ethanol (7% v/v; HCR-E) and without (HCR-C) was given to HCR rats (n = 8 per group) from 14 to 20 weeks of age that were weight matched and pair-fed to assure isocaloric intake. Hepatic triglyceride (TG) content and macro- and microvesicular steatosis were significantly greater in HCR-E compared with HCR-C (p High intrinsic aerobic fitness did not reduce ethanol-induced hepatic steatosis, but protected against ethanol-induced hepatic injury and systemic metabolic dysfunction in a high aerobic capacity rat model.

  17. Beyond the magic number four: Remapping high-capacity, pre-attentive, fragile working memory

    NARCIS (Netherlands)

    Zerr, P.; Gayet, S.; Mulder, K.T.; Sligte, I.G.; Stigchel, S. van der

    2017-01-01

    Visual short term memory allows us to access visual information after termination of its retinal input. Generally, a distinction is made between a robust, capacity-limited form (working memory, WM) and high-capacity, pre-attentive, maskable forms (sensory memory, e.g. fragile memory, FM). Eye

  18. VCSEL design and integration for high-capacity optical interconnects

    Science.gov (United States)

    Larsson, Anders; Gustavsson, Johan S.; Westbergh, Petter; Haglund, Erik; Haglund, Emanuel P.; Simpanen, Ewa; Lengyel, Tamas; Szczerba, Krzysztof; Karlsson, Magnus

    2017-02-01

    Vertical-cavity surface-emitting lasers and multi-mode fibers is the dominating technology for short-reach optical interconnects in datacenters and high performance computing systems at current serial rates of up to 25-28 Gbit/s. This is likely to continue at 50-56 Gbit/s. The technology shows potential for 100 Gbit/s.

  19. Capacity Payments in Restructured Markets under Low and High Penetration Levels of Renewable Energy

    Energy Technology Data Exchange (ETDEWEB)

    Jenkin, Thomas [National Renewable Energy Lab. (NREL), Golden, CO (United States); Beiter, Philipp [National Renewable Energy Lab. (NREL), Golden, CO (United States); Margolis, Robert [National Renewable Energy Lab. (NREL), Golden, CO (United States)

    2016-02-11

    remain in implementing capacity markets that provide both adequate operational and investment incentives, particularly under high-VRE scenarios with greater need for flexible capacity.

  20. Thermodynamic properties in the normal and superconducting states of Na(x)CoO(2)*yH(2)O powder measured by heat capacity experiments

    OpenAIRE

    Lorenz, B.; Cmaidalka, J.; Meng, R. L.; Chu, C. W.

    2003-01-01

    The heat capacity of superconducting Na(x)CoO(2)*yH(2)O was measured and the data are discussed based on three different models: The thermodynamic Ginzburg-Landau model, the BCS theory, and a model including the effects of line nodes in the superconducting gap function. The electronic heat capacity is separated from the lattice contribution in a thermodynamically consistent way maintaining the entropy balance of superconducting and normal states at the critical temperature. It is shown that f...

  1. Magneto-heat capacity study on Kondo lattice system Ce (Ni1− xCux ...

    Indian Academy of Sciences (India)

    The low temperature risein C p / T below 10 K under the influence of high magnetic fields was analysed using a multi-level Schottky effect. A gradual decrease of the total angular momentum (J) with the increase of applied magnetic fields indicated ascenario of screening of Ce 3 + magnetic moment while simultaneously the ...

  2. 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.

  3. Thermal Performance of High Temperature Titanium -- Water Heat Pipes by Multiple Heat Pipe Manufacturers

    Science.gov (United States)

    Sanzi, James L.

    2007-01-01

    Titanium - water heat pipes are being investigated for use in heat rejection systems for lunar and Mars fission surface power systems. Heat pipes provide an efficient and reliable means to transfer heat to a radiator heat rejection system. NASA Glenn Research Center requisitioned nine titanium water heat pipes from three vendors. Each vendor supplied three heat pipes 1.25 cm diameter by 1.1 meter long with each vendor selecting a different wick design. Each of the three heat pipes is slightly different in construction. Additional specifications for the heat pipes included 500 K nominal operating temperature, light weight, and freeze tolerance. The heat pipes were performance tested gravity-aided, in the horizontal position and at elevations against gravity at 450 K and 500 K. Performance of the three heat pipes is compared. The heat pipe data will be used to verify models of heat pipe radiators that will be used in future space exploration missions.

  4. Thermal Performance of High Temperature Titanium-Water Heat Pipes by Multiple Heat Pipe Manufacturers

    Science.gov (United States)

    Sanzi, James L.

    2007-01-01

    Titanium-water heat pipes are being investigated for use in heat rejection systems for lunar and Mars fission surface power systems. Heat pipes provide an efficient and reliable means to transfer heat to a radiator heat rejection system. NASA Glenn Research Center requisitioned nine titanium water heat pipes from three vendors. Each vendor supplied three heat pipes 1.25 cm diameter by 1.1 meter long with each vendor selecting a different wick design. Each of the three heat pipes is slightly different in construction. Additional specifications for the heat pipes included 500 K nominal operating temperature, light weight, and freeze tolerance. The heat pipes were performance tested gravity-aided, in the horizontal position and at elevations against gravity at 450 and 500 K. Performance of the three heat pipes is compared. The heat pipe data will be used to verify models of heat pipe radiators that will be used in future space exploration missions.

  5. Effect of Al₂O₃ nanoparticle dispersion on the specific heat capacity of a eutectic binary nitrate salt for solar power applications

    OpenAIRE

    Hu, Y.; Y. He; Z.; Zhang; Wen, D

    2017-01-01

    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 Al₂O₃ nanoparticles on its specific heat capacity (cp) was investigated. The effects of the mass fraction of nanoparticles on the cp of the composite nanofluid were analyzed, using both differential scanning calorimetry m...

  6. Gas Nonideality at One Atmosphere Revealed through Speed of Sound Measurements and Heat Capacity Determinations

    Science.gov (United States)

    Halpern, Arthur M.; Liu, Allen

    2008-01-01

    Using an easy-to-make cylindrical resonator, students can measure the speed of sound in a gas, u, with sufficiently high precision (by locating standing-wave Lissajous patterns on an oscilloscope) to observe real gas properties at one atmosphere and 300 K. For CO[subscript 2] and SF[subscript 6], u is found to be 268.83 and 135.25 m s[superscript…

  7. Preliminary Heat Transfer Characteristics of RP-2 Fuel as Tested in the High Heat Flux Facility (PREPRINT)

    National Research Council Canada - National Science Library

    Irvine, S. A; Burns, R. M

    2005-01-01

    ...., high aspect ratio cooling channels, various fuel thermal stability issues, material compatibility, heat transfer capability, effects related to dissolved oxygen or specific sulfur species contained...

  8. A high mitochondrial transport rate characterizes CNS neurons with high axonal regeneration capacity.

    Directory of Open Access Journals (Sweden)

    Romain Cartoni

    Full Text Available Improving axonal transport in the injured and diseased central nervous system has been proposed as a promising strategy to improve neuronal repair. However, the contribution of each cargo to the repair mechanism is unknown. DRG neurons globally increase axonal transport during regeneration. Because the transport of specific cargos after axonal insult has not been examined systematically in a model of enhanced regenerative capacity, it is unknown whether the transport of all cargos would be modulated equally in injured central nervous system neurons. Here, using a microfluidic culture system we compared neurons co-deleted for PTEN and SOCS3, an established model of high axonal regeneration capacity, to control neurons. We measured the axonal transport of three cargos (mitochondria, synaptic vesicles and late endosomes in regenerating axons and found that the transport of mitochondria, but not the other cargos, was increased in PTEN/SOCS3 co-deleted axons relative to controls. The results reported here suggest a pivotal role for this organelle during axonal regeneration.

  9. Experimental and theoretical analysis of nanofluids based on high temperature-heat transfer fluid with enhanced thermal properties

    Science.gov (United States)

    Navas, Javier; Sánchez-Coronilla, Antonio; Martín, Elisa I.; Gómez-Villarejo, Roberto; Teruel, Miriam; Gallardo, Juan Jesús; Aguilar, Teresa; Alcántara, Rodrigo; Fernández-Lorenzo, Concha; Martín-Calleja, Joaquín

    2017-04-01

    In this work, nanofluids were prepared using commercial Cu nanoparticles and a commercial high temperature-heat transfer Fluid (eutectic mixture of diphenyl oxide and biphenyl) as the base fluid, which is used in concentrating solar power (CSP) plants. Different properties such as density, viscosity, heat capacity and thermal conductivity were characterized. Nanofluids showed enhanced heat transfer efficiency. In detail, the incorporation of Cu nanoparticles led to an increase of the heat capacity up to 14%. Also, thermal conductivity was increased up to 13%. Finally, the performance of the nanofluids prepared increased up to 11% according to the Dittus-Boelter correlation. On the other hand, equilibrium molecular dynamics simulation was used to model the experimental nanofluid system studied. Thermodynamic properties such as heat capacity and thermal conductivity were calculated and the results were compared with experimental data. The analysis of the radial function distributions (RDFs) and the inspection of the spatial distribution functions (SDFs) indicate the important role that plays the metal-oxygen interaction in the system. Dynamic properties such as the diffusion coefficients of base fluid and nanofluid were computed according to Einstein relation by computing the mean square displacement (MSD). Supplementary online material is available in electronic form at http://www.epjap.org

  10. 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.

  11. High Aerobic Capacity Mitigates Changes in the Plasma Metabolomic Profile Associated with Aging.

    Science.gov (United States)

    Falegan, Oluyemi S; Vogel, Hans J; Hittel, Dustin S; Koch, Lauren G; Britton, Steven L; Hepple, Russ T; Shearer, Jane

    2017-02-03

    Advancing age is associated with declines in maximal oxygen consumption. Declines in aerobic capacity not only contribute to the aging process but also are an independent risk factor for morbidity, cardiovascular disease, and all-cause mortality. Although statistically convincing, the relationships between aerobic capacity, aging, and disease risk remain largely unresolved. To this end, we employed sensitive, system-based metabolomics approach to determine whether enhanced aerobic capacity could mitigate some of the changes seen in the plasma metabolomic profile associated with aging. Metabolomic profiles of plasma samples obtained from young (13 month) and old (26 month) rats bred for low (LCR) or high (HCR) running capacity using proton nuclear magnetic resonance spectroscopy ( 1 H NMR) were examined. Results demonstrated strong profile separation in old and low aerobic capacity rats, whereas young and high aerobic capacity rat models were less predictive. Significantly differential metabolites between the groups include taurine, acetone, valine, and trimethylamine-N-oxide among other metabolites, specifically citrate, succinate, isovalerate, and proline, were differentially increased in older HCR animals compared with their younger counterparts. When interactions between age and aerobic capacity were examined, results demonstrated that enhanced aerobic capacity could mitigate some but not all age-associated alterations in the metabolomic profile.

  12. Experimental Evaluation of High Performance Integrated Heat Pump

    Energy Technology Data Exchange (ETDEWEB)

    Miller, William A [ORNL; Berry, Robert [Unico Inc., St. Louis, MO; Durfee, Neal [ORNL; Baxter, Van D [ORNL

    2016-01-01

    Integrated heat pump (IHP) technology provides significant potential for energy savings and comfort improvement for residential buildings. In this study, we evaluate the performance of a high performance IHP that provides space heating, cooling, and water heating services. Experiments were conducted according to the ASHRAE Standard 206-2013 where 24 test conditions were identified in order to evaluate the IHP performance indices based on the airside performance. Empirical curve fits of the unit s compressor maps are used in conjunction with saturated condensing and evaporating refrigerant conditions to deduce the refrigerant mass flowrate, which, in turn was used to evaluate the refrigerant side performance as a check on the airside performance. Heat pump (compressor, fans, and controls) and water pump power were measured separately per requirements of Standard 206. The system was charged per the system manufacturer s specifications. System test results are presented for each operating mode. The overall IHP performance metrics are determined from the test results per the Standard 206 calculation procedures.

  13. Heat conductivity of high-temperature thermal insulators

    Science.gov (United States)

    Kharlamov, A. G.

    The book deals essentially with the mechanisms of heat transfer by conduction, convection, and thermal radiation in absorbing and transmitting media. Particular attention is given to materials for gas-cooled reactor systems, the temperature dependent conductivities of high-temperature insulations in vacuum, and the thermal conductivities of MgO, Al2O3, ZrO2, and other powders at temperatures up to 2000 C. The thermal conductivity of pyrolitic graphite and graphite foam are studied.

  14. Effect of High Pressure and Heat on Bacterial Toxins

    Directory of Open Access Journals (Sweden)

    Dirk Margosch

    2005-01-01

    Full Text Available Even though the inactivation of microorganisms by high pressure treatment is a subject of intense investigations, the effect of high pressure on bacterial toxins has not been studied so far. In this study, the influence of combined pressure/temperature treatment (0.1 to 800 MPa and 5 to 121 °C on bacterial enterotoxins was determined. Therefore, heat-stable enterotoxin (STa of cholera toxin (CT from Vibrio cholerae, staphylococcal enterotoxins A-E, haemolysin BL (HBL from Bacillus cereus, and Escherichia coli (STa were subjected to different treatment schemes. Structural alterations were monitored in enzyme immunoassays (EIAs. Cytotoxicity of the pressure treated supernatant of toxigenic B. cereus DSM 4384 was investigated with Vero cells. High pressure of 200 to 800 MPa at 5 °C leads to a slight increase of the reactivity of the STa of E. coli. However, reactivity decreased at 800 MPa and 80 °C to (66±21 % after 30 min and to (44±0.3 % after 128 min. At ambient pressure no decrease in EIA reactivity could be observed after 128 min. Pressurization (0.1 to 800 MPa of heat stable monomeric staphylococcal toxins at 5 and 20 °C showed no effect. A combined heat (80 °C and pressure (0.1 to 800 MPa treatment lead to a decrease in the immuno-reactivity to 20 % of its maximum. For cholera toxin a significant loss in latex agglutination was observable only at 80 °C and 800 MPa for holding times higher than 20 min. Interestingly, the immuno-reactivity of B. cereus HBL toxin increased with the increase of pressure (182 % at 800 MPa, 30 °C, and high pressure showed only minor effects on cytotoxicity to Vero cells. Our results indicate that pressurization can increase inactivation observed by heat treatment, and combined treatments may be effective at lower temperatures and/or shorter incubation time.

  15. Multi-core Fibers in Submarine Networks for High-Capacity Undersea Transmission Systems

    DEFF Research Database (Denmark)

    Nooruzzaman, Md; Morioka, Toshio

    2017-01-01

    Application of multi-core fibers in undersea networks for high-capacity submarine transmission systems is studied. It is demonstrated how different architectures of submerged branching unit affect network component counts in long-haul undersea transmission systems......Application of multi-core fibers in undersea networks for high-capacity submarine transmission systems is studied. It is demonstrated how different architectures of submerged branching unit affect network component counts in long-haul undersea transmission systems...

  16. Frequency Assignment for Joint Aerial Layer Network High-Capacity Backbone

    Science.gov (United States)

    2017-08-11

    is the resource management problems involving multiple antennas per aerial platform, limited available bandwidth and geometric blockage involving the...ARL-TR-8093•AUG 2017 US Army Research Laboratory Frequency Assignment for Joint Aerial Layer Network High -Capacity Backbone by Peng Wang and Brian...2017 US Army Research Laboratory Frequency Assignment for Joint Aerial Layer Network High -Capacity Backbone by Peng Wang and Brian Henz Computational

  17. High-SNR Capacity of AWGN Channels with Generic Alphabet Constraints

    Science.gov (United States)

    2017-01-01

    work with differential entropy in a coordinate-independent manner, as manifolds generally cannot be parameterized entirely by any single coordinate...asymptotic capacity in the high-SNR limit is computed for such AWGN channels with manifold constraints in two variants: a compact alphabet manifold ...and a non-compact scale-invariant alphabet manifold with an additional average power constraint on the input distribution. The high-SNR capacity

  18. An automated flow calorimeter for heat capacity and enthalpy measurements at elevated temperatures and pressures: Progress report, March 1, 1987-February 29, 1988

    Energy Technology Data Exchange (ETDEWEB)

    Yesavage, V.F.

    1987-10-01

    The need for thermal property data at process conditions in the design of petrochemical and synfuel plants has been well documented. As such, the primary objective of this work is to construct an automated flow calorimeter to measure isobaric heat capacities and enthalpies of vaporization over the range 0 to 30MPa and 300 to 700K with an anticipated accuracy of 0.1%. The method of measurement is by the traditional electrical power input technique with a unique calorimeter design utilizing a concentric coil/radiation shield structure which minimizes heat loss errors and simplifies the replacement of plugged components. Flow generation is accomplished with a precision Ruska pump eliminating the need for on-line flow rate measurement. In addition, the proposed instrument will be fully automated minimizing the need for highly skilled operators which had previously been a severe limitation with this type of instrument. Significant progress has been made on the project this last year with the completion of construction of all major system hardware components and the associated automation electronics. Initial tests of the equipment are encouraging and no significant delays are foreseen in the completion of the apparatus. During the next year the automation and data acquisition software will be written and the completed unit will be tested with water. 7 figs.

  19. Ultra-High Capacity Silicon Photonic Interconnects through Spatial Multiplexing

    Science.gov (United States)

    Chen, Christine P.

    -fabrication. Through ModePROP simulations, optimizing device performance dynamically post-fabrication is analyzed, through either electro-optical or thermo-optical means. By biasing the arm introducing the slight spectral offset, we can quantifiably improve device performance. Scaling bandwidth is experimentally demonstrated through the device at 3 modes, 2 wavelengths, and 40 Gb/s data rate for 240 Gb/s aggregate bandwidth, with the potential to reduce power penalty per the device optimization process we described. A main motivation for this on-chip spatial multiplexing is the need to reduce costs. As the laser source serves as the greatest power consumer in an optical system, mode-division multiplexing and other forms of spatial multiplexing can be implemented to push its potentially prohibitive cost metrics down. In order to demonstrate an intelligent platform capable of dynamically multicasting data and reallocating power as needed by the system, we must first initialize the switch fabric to control with an electronic interface. A dithering mechanism, whereby exact cross, bar, and sub-percentage states are enforced through the device, is described here. Such a method could be employed for actuating the device table of bias values to states automatically. We then employ a dynamic power reallocation algorithm through a data acquisition unit, showing real-time channel recovery for channels experiencing power loss by diverting power from paths that could tolerate it. The data that is being multicast through the system is experimentally shown to be error-free at 40 Gb/s data rate, when transmitting from one to three clients and going from automatic bar/cross states to equalized power distribution. For the last portion of this topic, the switch fabric was inserted into a high-performance computing system. In order to run benchmarks at 10 Gb/s data ontop of the switch fabric, a newer model of the control plane was implemented to toggle states according to the command issued by the server

  20. High resolution heat atlases for demand and supply mapping

    Directory of Open Access Journals (Sweden)

    Bernd Möller

    2014-02-01

    Full Text Available Significant reductions of heat demand, low-carbon and renewable energy sources, and district heating are key elements in 100% renewable energy systems. Appraisal of district heating along with energy efficient buildings and individual heat supply requires a geographical representation of heat demand, energy efficiency and energy supply. The present paper describes a Heat Atlas built around a spatial database using geographical information systems (GIS. The present atlas allows for per-building calculations of potentials and costs of energy savings, connectivity to existing district heat, and current heat supply and demand. For the entire building mass a conclusive link is established between the built environment and its heat supply. The expansion of district heating; the interconnection of distributed district heating systems; or the question whether to invest in ultra-efficient buildings with individual supply, or in collective heating using renewable energy for heating the current building stock, can be based on improved data.

  1. Introduction of Differential Scanning Calorimetry in a General Chemistry Laboratory Course: Determination of Heat Capacity of Metals and Demonstration of Law of Dulong and Petit

    Science.gov (United States)

    D'Amelia, Ronald P.; Stracuzzi, Vincent; Nirode, William F.

    2008-01-01

    Today's general chemistry students are introduced to many of the principles and concepts of thermodynamics. In first-year general chemistry undergraduate courses, thermodynamic properties such as heat capacity are frequently discussed. Classical calorimetric methods of analysis and thermal equilibrium experiments are used to determine heat…

  2. High-Capacity Layered-Spinel Cathodes for Li-Ion Batteries.

    Science.gov (United States)

    Nayak, Prasant Kumar; Levi, Elena; Grinblat, Judith; Levi, Mikhael; Markovsky, Boris; Munichandraiah, N; Sun, Yang Kook; Aurbach, Doron

    2016-09-08

    Li and Mn-rich layered oxides with the general structure x Li2 MnO3 ⋅(1-x) LiMO2 (M=Ni, Mn, Co) are promising cathode materials for Li-ion batteries because of their high specific capacity, which may be greater than 250 mA h g(-1) . However, these materials suffer from high first-cycle irreversible capacity, gradual capacity fading, limited rate capability and discharge voltage decay upon cycling, which prevent their commercialization. The decrease in average discharge voltage is a major issue, which is ascribed to a structural layered-to-spinel transformation upon cycling of these oxide cathodes in wide potential ranges with an upper limit higher than 4.5 V and a lower limit below 3 V versus Li. By using four elements systems (Li, Mn, Ni, O) with appropriate stoichiometry, it is possible to prepare high capacity composite cathode materials that contain LiMn1.5 Ni0.5 O4 and Lix Mny Niz O2 components. The Li and Mn-rich layered-spinel cathode materials studied herein exhibit a high specific capacity (≥200 mA h g(-1) ) with good capacity retention upon cycling in a wide potential domain (2.4-4.9 V). The effect of constituent phases on their electrochemical performance, such as specific capacity, cycling stability, average discharge voltage, and rate capability, are explored here. This family of materials can provide high specific capacity, high rate capability, and promising cycle life. Using Co-free cathode materials is also an obvious advantage of these systems. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  3. Workshop on high heat load x-ray optics

    Energy Technology Data Exchange (ETDEWEB)

    1990-01-01

    A workshop on High Heat Load X-Ray Optics'' was held at Argonne National Laboratory on August 3--5, 1989. The object of this workshop was to discuss recent advances in the art of cooling x-ray optics subject to high heat loads from synchrotron beams. The cooling of the first optical element in the intense photon beams that will be produced in the next generation of synchrotron sources is recognized as one of the major challenges that must be faced before one will be able to use these very intense beams in future synchrotron experiments. Considerable advances have been made in this art during the last few years, but much work remains to be done before the heating problem can be said to be completely solved. Special emphasis was placed on recent cooling experiments and detailed finite element'' and finite difference'' calculations comparing experiment with theory and extending theory to optimize performance.

  4. New heat treatment process for advanced high-strength steels

    Science.gov (United States)

    Bublíková, D.; Jeníček, Š.; Vorel, I.; Mašek, B.

    2017-02-01

    Today’s advanced steels are required to possess high strength and ductility. It can be achieved by choosing an appropriate steel chemistry which has a substantial effect on the properties obtained by heat treatment. Mechanical properties influenced the presence of retained austenite in the final structure. Steels of this group typically require complicated heat treatment which places great demands on the equipment used. The present paper introduces new procedures aimed at simplifying the heat treatment of high-strength steels with the use of material-technological modelling. Four experimental steels were made and cast, whose main alloying additions were manganese, silicon, chromium, molybdenum and nickel. The steels were treated using the Q-P process with subsequent interrupted quenching. The resulting structure was a mixture of martensite and retained austenite. Strength levels of more than 2000 MPa combined with 10-15 % elongation were obtained. These properties thus offer potential for the manufacture of intricate closed-die forgings with a reduced weight. Intercritical annealing was obtained structure not only on the basis of martensite, but also with certain proportion of bainitic ferrite and retained austenite.

  5. An Alternative Approach for High Speed Railway Carrying Capacity Calculation Based on Multiagent Simulation

    Directory of Open Access Journals (Sweden)

    Mo Gao

    2016-01-01

    Full Text Available It is a multiobjective mixed integer programming problem that calculates the carrying capacity of high speed railway based on mathematical programming method. The model is complex and difficult to solve, and it is difficult to comprehensively consider the various influencing factors on the train operation. The multiagent theory is employed to calculate high speed railway carrying capacity. In accordance with real operations of high speed railway, a three-layer agent model is developed to simulate the operating process of high speed railway. In the proposed model, railway network agent, line agent, station agent, and train agent are designed, respectively. To validate the proposed model, a case study is performed for Beijing–Shanghai high speed railway by using NetLogo software. The results are consistent with the actual data, which implies that the proposed multiagent method is feasible to calculate the carrying capacity of high speed railway.

  6. 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.

  7. Maxwell-Cattaneo Heat Convection and Thermal Stresses Responses of a Semi-Infinite Medium to High-Speed Laser Heating due to High Speed Laser Heating

    Directory of Open Access Journals (Sweden)

    Abdallah I. A.

    2009-07-01

    Full Text Available Based on Maxwell-Cattaneo convection equation, the thermoelasticity problem is in- vestigated in this paper. The analytic solution of a boundary value problem for a semi- infinite medium with traction free surface heated by a high-speed laser-pulses have Dirac temporal profile is solved. The temperature, the displacement and the stresses distributions are obtained analytically using the Laplace transformation, and discussed at small time duration of the laser pulses. A numerical study for Cu as a target is performed. The results are presented graphically. The obtained results indicate that the small time duration of the laser pulses has no e ect on the finite velocity of the heat con- ductivity, but the behavior of the stress and the displacement distribution are affected due to the pulsed heating process and due to the structure of the governing equations.

  8. Effect of crystallinity and irradiation on thermal properties and specific heat capacity of LDPE and LDPE/EVA

    Energy Technology Data Exchange (ETDEWEB)

    Borhani zarandi, Mahmoud, E-mail: mborhani@yazduni.ac.ir [Physics Department, Yazd University, Yazd (Iran, Islamic Republic of); Amrollahi Bioki, Hojjat; Mirbagheri, Zahra-alsadat [Physics Department, Yazd University, Yazd (Iran, Islamic Republic of); Tabbakh, Farshid [Institute of Nuclear Science and Technology, Tehran (Iran, Islamic Republic of); Mirjalili, Ghazanfar [Physics Department, Yazd University, Yazd (Iran, Islamic Republic of)

    2012-01-15

    In this paper a series of low-density polyethylene (LDPE) blends with different percentages (10%, 20%, and 30%) of EVA and sets of low-density polyethylene sheets were prepared. This set consists of four subsets, which were made under different cooling methods: fast cooling in liquid nitrogen, cooling with cassette, exposing in open air, and cooling in oven, to investigate the crystallinity effects. All of the samples were irradiated with 10 MeV electron-beam in the dose range of 0-250 kGy using a Rhodotron accelerator system. The variation of thermal conductivity (k) and specific heat capacity (C{sub p}) of all of the samples were measured. We found that, for the absorption dose less than 150 kGy, k of the LDPE samples at a prescribed temperature range decreased by increasing the amount of dose, but then the change is insignificant. With increasing the crystallinity, k of the LDPE samples increased, whereas C{sub p} of this material is decreased. In the case of LDPE/EVA blends, for the dose less than 150 kGy, C{sub p} (at 40 Degree-Sign C) and k (in average) decreased, but then the change is insignificant. With increasing the amount of additive (EVA), C{sub p} and k increased.

  9. Temperature dependence of the heat capacities in the solid state of 18 mono-, di-, and poly-saccharides

    Energy Technology Data Exchange (ETDEWEB)

    Hernandez-Segura, Gerardo O. [Laboratorio de Biofisicoquimica, Departamento de Fisicoquimica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Mexico D.F. 04510 (Mexico); Campos, Myriam [Departamento de Quimica, Centro de Investigacion y Estudios Avanzados del I.P.N., Apdo. Postal 14-740, Mexico D.F. 07000 (Mexico); Costas, Miguel [Laboratorio de Biofisicoquimica, Departamento de Fisicoquimica, Facultad de Quimica, Universidad Nacional Autonoma de Mexico, Mexico D.F. 04510 (Mexico)], E-mail: costasmi@servidor.unam.mx; Torres, Luis A. [Departamento de Quimica, Centro de Investigacion y Estudios Avanzados del I.P.N., Apdo. Postal 14-740, Mexico D.F. 07000 (Mexico)], E-mail: ltorres@cinvestav.mx

    2009-01-15

    The temperature dependence of the heat capacities in solid state C{sub p}(T) of 18 mono-, di-, and poly-saccharides has been determined using a power-compensation differential scanning calorimeter. The saccharides were {alpha}-D-xylose, D-ribose, 2-deoxy-D-ribose, methyl-{beta}-D-ribose, {alpha}-D-glucose, 2-deoxy-D-glucose, {alpha}-D-mannose, {beta}-D-fructose, {alpha}-D-galactose, methyl-{alpha}-D-glucose, sucrose, maltose monohydrate, {alpha}-lactose monohydrate, cellobiose, maltotriose, N-acetyl-D-glucosamine, {alpha}-cyclodextrin, and {beta}-cyclodextrin. The measurements were carried out at atmospheric pressure and from T = (288.15 to 358.15) K for 15 saccharides and from T = (288.15 to 328.15) K for D-ribose, 2-deoxy-D-ribose, and methyl-{beta}-D-ribose. The present results are compared against literature values both at single temperatures, where most of the data are available, and throughout a range of temperatures, i.e., for C{sub p}(T). The predictions of a recently published correlation for organic solids are briefly discussed. By grouping saccharides in subsets, our present results can be used to compare amongst saccharide isomers and to assess the effect of different chemical groups and molecular size.

  10. High resolution heat atlases for demand and supply mapping

    DEFF Research Database (Denmark)

    Möller, Bernd; Nielsen, Steffen

    2014-01-01

    , and current heat supply and demand. For the entire building mass a conclusive link is established between the built environment and its heat supply. The expansion of district heating; the interconnection of distributed district heating systems; or the question whether to invest in ultra-efficient buildings...... with individual supply, or in collective heating using renewable energy for heating the current building stock, can be based on improved data....

  11. Practitioner consensus on the determinants of capacity building practice in high-income countries.

    Science.gov (United States)

    Swanepoel, Elizabeth; Fox, Ann; Hughes, Roger

    2015-07-01

    To assess and develop consensus among experienced public health nutrition practitioners from high-income countries regarding conceptualisation of capacity building in practice, and to test the content validity of a previously published conceptual framework for capacity building in public health nutrition practice. A Delphi study involving three iterations of email-delivered questionnaires testing a range of capacity determinants derived from the literature. Consensus was set at >50% of panellists ranking items as 'very important' on a five-point Likert scale across three survey rounds. Public health nutrition practice in Australia, the UK, Canada and the USA. Public health nutrition practitioners and academics. Result A total of thirty expert panellists (68% of an initial panel of forty-four participants) completed all three rounds of Delphi questionnaires. Consensus identified determinants of capacity building in practice including partnerships, resourcing, community development, leadership, workforce development, intelligence and quality of project management. The findings from the study suggest there is broad agreement among public health nutritionists from high-income countries about how they conceptualise capacity building in public health nutrition practice. This agreement suggests considerable content validity for a capacity building conceptual framework proposed by Baillie et al. (Public Health Nutr 12, 1031-1038). More research is needed to apply the conceptual framework to the implementation and evaluation of strategies that enhance the practice of capacity building approaches by public health nutrition professionals.

  12. Boiling Heat-Transfer Processes and Their Application in the Cooling of High Heat Flux Devices

    Science.gov (United States)

    1993-06-01

    presented previously in Eq. (8). Bjorge , et al. (Ref. 170) and Stephan and Auracher (Ref. 171) later presented variations of the superposition approach...ofHeat Transfer, Vol. 90, May 1968, pp. 239-247. 170. Bjorge , R. W., Hall, G. R., and Rohsenow, W. M. "Correlation of Forced Convection Boiling Heat... Communications on Heat Mass Transfer, Vol. 18, No.5, September-October 1991, pp. 659-667. 383. Boyd, R. D., Sr. "Critical Heat Flux and Heat Transfer

  13. Design and demonstration of heat pipe cooling for NASP and evaluation of heating methods at high heating rates

    Energy Technology Data Exchange (ETDEWEB)

    Merrigan, M.A.; Sena, J.T.

    1989-01-01

    An evaluation of two heating methods for demonstration of NASP leading edge heat pipe technology was conducted. The heating methods were and rf induction heated plasma jet and direct rf induction. Tests were conducted to determine coupling from the argon plasma jet on a surface physically similar to a heat pipe. A molybdenum tipped calorimeter was fabricated and installed in an rf induction heated plasma jet for the test. The calorimetric measurements indicated a maximum power coupling of approximately 500 W/cm{sup 2} with the rf plasma jet. The effect of change in gas composition on the heating rate was investigated using helium. An alternative to the plasma heating of a heat pipe tip, an rf concentrator was evaluated for coupling to the hemispherical tip of a heat pipe. A refractory metal heat pipe was designed, fabricated, and tested for the evaluation. The heat pipe was designed for operation at 1400 to 1900 K with power input to 1000 W/cm{sup 2} over a hemispherical nose tip. Power input of 800 W/cm{sup 2} was demonstrated using the rf concentrator. 2 refs., 13 figs.

  14. Hemispherical total emissivity and specific heat capacity of deeply undercooled Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 melts

    Science.gov (United States)

    Busch, R.; Kim, Y. J.; Johnson, W. L.; Rulison, A. J.; Rhim, W. K.; Isheim, D.

    1995-06-01

    High-temperature high-vacuum electrostatic levitation (HTHVESL) and differential scanning calorimetry (DSC) were combined to determine the hemispherical total emissivity ɛT, and the specific heat capacity cp, of the undercooled liquid and throughout the glass transition of the Zr41.2Ti13.8Cu12.5Ni10.0Be22.5 bulk metallic glass forming alloy. The ratio of cp/ɛT as a function of undercooling was determining from radiative cooling curves measured in the HTHVESL. Using specific heat capacity data obtained by DSC investigations close to the glass transition and above the melting point, ɛT and cp were separated and the specific heat capacity of the whole undercooled liquid region was determined. Furthermore, the hemispherical total emissivity of the liquid was found to be about 0.22 at 980 K. On undercooling the liquid, the emissivity decreases to approximately 0.18 at about 670 K, where the undercooled liquid starts to freeze to a glass. No significant changes of the emissivity are observed as the alloy undergoes the glass transition.

  15. High-Efficiency, High-Capacity, Low-NOx Aluminum Melting Using Oxygen-Enhanced Combustion

    Energy Technology Data Exchange (ETDEWEB)

    D' Agostini, M.D.

    2000-06-02

    This report describes the development and application of a novel oxygen enhanced combustion system with an integrated vacuum swing adsorption (VSA) oxygen supply providing efficient, low NOx melting in secondary aluminum furnaces. The mainstay of the combustion system is a novel air-oxy-natural gas burner that achieves high productivity and energy efficiency with low NOx emissions through advanced mixing concepts and the use of separate high- and low-purity oxidizer streams. The technology was installed on a reverberatory, secondary aluminum melting plant at the Wabash Aluminum Alloy's Syracuse, N.Y. plant, where it is currently in operation. Field testing gave evidence that the new burner technology meets the stringent NOx emissions target of 0.323 lb NO2/ton aluminum, thus complying with regulations promulgated by Southern California's South Coast Air Quality Management District (SCAQMD). Test results also indicated that the burner technology exceeded fuel efficiency and melting capacity goals. Economic modeling showed that the novel air-oxy-fuel (ADF) combustion technology provides a substantial increase in furnace profitability relative to air-fuel operation. Model results also suggest favorable economics for the air-oxy-fuel technology relative to a full oxy-fuel conversion of the furnace.

  16. Recycling potential for low voltage and high voltage high rupturing capacity fuse links.

    Science.gov (United States)

    Psomopoulos, Constantinos S; Barkas, Dimitrios A; Kaminaris, Stavros D; Ioannidis, George C; Karagiannopoulos, Panagiotis

    2017-12-01

    Low voltage and high voltage high-rupturing-capacity fuse links are used in LV and HV installations respectively, protecting mainly the LV and HV electricity distribution and transportation networks. The Waste Electrical and Electronic Equipment Directive (2002/96/EC) for "Waste of electrical and electronic equipment" is the main related legislation and as it concerns electrical and electronic equipment, it includes electric fuses. Although, the fuse links consist of recyclable materials, only small scale actions have been implemented for their recycling around Europe. This work presents the possibilities for material recovery from this specialized industrial waste for which there are only limited volume data. Furthermore, in order to present the huge possibilities and environmental benefits, it presents the potential for recycling of HRC fuses used by the Public Power Corporation of Greece, which is the major consumer for the country, but one of the smallest ones in Europe and globally, emphasizing in this way in the issue. According to the obtained results, fuse recycling could contribute to the effort for minimize the impacts on the environment through materials recovery and reduction of the wastes' volume disposed of in landfills. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. 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....

  18. An Evaluation of Layer 2 and Layer 3 Routing on High Capacity Aerial Directional Links

    Science.gov (United States)

    2016-10-30

    loaded as overall traffic that is generated is much less than the capacity of each link in the topology . The following metrics are used to assess the... topology . • Efficiency: This metric is represented as a ratio of total goodput to total traffic sent, where total goodput is defined as the total data...Surface Network F Aerial High Capacity Backbone Fig. 4: 9 Node Emulated Topology The parameters that affect routing performance metrics for Batman-Adv

  19. Preparation and characterization of magnetic polymer nanospheres with high protein binding capacity

    Science.gov (United States)

    Liu, Xianqiao; Guan, Yueping; Liu, Huizhou; Ma, Zhiya; Yang, Yu; Wu, Xiaobing

    2005-05-01

    A novel magnetic support with high protein binding capacity was prepared by mini-emulsion polymerization. The magnetic poly(methacrylate-divinylbenzene) nanospheres prepared are 390 nm in diameter with narrow size distribution and star-like external morphology which leads to a large increase in specific surface area. Experimental results indicate that the maximum protein binding capacity is 316 mg bovine hemoglobin (BHb)/g support.

  20. Preparation and characterization of magnetic polymer nanospheres with high protein binding capacity

    Energy Technology Data Exchange (ETDEWEB)

    Liu Xianqiao [Laboratory of Separation Science and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, P.O. Box 353, Beijing, 100080 (China); Guan Yueping [Laboratory of Separation Science and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, P.O. Box 353, Beijing, 100080 (China); Liu Huizhou [Laboratory of Separation Science and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, P.O. Box 353, Beijing, 100080 (China)]. E-mail: hzliu@home.ipe.ac.cn; Ma Zhiya [Laboratory of Separation Science and Engineering, State Key Laboratory of Biochemical Engineering, Institute of Process Engineering, Chinese Academy of Sciences, P.O. Box 353, Beijing, 100080 (China); Yang Yu [AGTC Gene Technology Company Ltd., Beijing 100176 (China); Wu Xiaobing [AGTC Gene Technology Company Ltd., Beijing 100176 (China)

    2005-05-15

    A novel magnetic support with high protein binding capacity was prepared by mini-emulsion polymerization. The magnetic poly(methacrylate-divinylbenzene) nanospheres prepared are 390 nm in diameter with narrow size distribution and star-like external morphology which leads to a large increase in specific surface area. Experimental results indicate that the maximum protein binding capacity is 316 mg bovine hemoglobin (BHb)/g support.

  1. Predicting high harmonic ion cyclotron heating efficiency in Tokamak plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Green, David L [ORNL; Jaeger, E. F. [XCEL; Berry, Lee A [ORNL; Chen, Guangye [ORNL; Ryan, Philip Michael [ORNL; Canik, John [ORNL

    2011-01-01

    Observations of improved radio frequency (RF) heating efficiency in high-confinement (H-) mode plasmas on the National Spherical Tokamak Experiment (NSTX) are investigated by whole-device linear simulation. We present the first full-wave simulation to couple kinetic physics of the well confined core plasma to the poorly confined scrape-off plasma. The new simulation is used to scan the launched fast-wave spectrum and examine the steady-state electric wave field structure for experimental scenarios corresponding to both reduced, and improved RF heating efficiency. We find that launching toroidal wave-numbers that required for fast-wave propagation excites large amplitude (kVm 1 ) coaxial standing modes in the wave electric field between the confined plasma density pedestal and conducting vessel wall. Qualitative comparison with measurements of the stored plasma energy suggest these modes are a probable cause of degraded heating efficiency. Also, the H-mode density pedestal and fast-wave cutoff within the confined plasma allow for the excitation of whispering gallery type eigenmodes localised to the plasma edge.

  2. Modeling of high power ICRF heating experiments on TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, C.K.; Wilson, J.R.; Bell, M.; Fredrickson, E.; Hosea, J.C.; Majeski, R.; Ramsey, A.; Rogers, J.H.; Schilling, G.; Skinner, C.; Stevens, J.E.; Taylor, G.; Wong, K.L. (Princeton Univ., NJ (United States). Plasma Physics Lab.); Khudaleev, A.; Petrov, M.P. (Ioffe Inst., St. Petersburg (Russian Federation)); Murakami, M. (Oak Ridge National Lab., TN (United States))

    1993-01-01

    Over the past two years, ICRF heating experiments have been performed on TFTR in the hydrogen minority heating regime with power levels reaching 11.2 MW in helium-4 majority plasmas and 8.4 MW in deuterium majority plasmas. For these power levels, the minority hydrogen ions, which comprise typically less than 10% of the total electron density, evolve into la very energetic, anisotropic non-Maxwellian distribution. Indeed, the excess perpendicular stored energy in these plasmas associated with the energetic minority tail ions is often as high as 25% of the total stored energy, as inferred from magnetic measurements. Enhanced losses of 0.5 MeV protons consistent with the presence of an energetic hydrogen component have also been observed. In ICRF heating experiments on JET at comparable and higher power levels and with similar parameters, it has been suggested that finite banana width effects have a noticeable effect on the ICRF power deposition. In particular, models indicate that finite orbit width effects lead to a reduction in the total stored energy and of the tail energy in the center of the plasma, relative to that predicted by the zero banana width models. In this paper, detailed comparisons between the calculated ICRF power deposition profiles and experimentally measured quantities will be presented which indicate that significant deviations from the zero banana width models occur even for modest power levels (P[sub rf] [approximately] 6 MW) in the TFTR experiments.

  3. Modeling of high power ICRF heating experiments on TFTR

    Energy Technology Data Exchange (ETDEWEB)

    Phillips, C.K.; Wilson, J.R.; Bell, M.; Fredrickson, E.; Hosea, J.C.; Majeski, R.; Ramsey, A.; Rogers, J.H.; Schilling, G.; Skinner, C.; Stevens, J.E.; Taylor, G.; Wong, K.L. [Princeton Univ., NJ (United States). Plasma Physics Lab.; Khudaleev, A.; Petrov, M.P. [Ioffe Inst., St. Petersburg (Russian Federation); Murakami, M. [Oak Ridge National Lab., TN (United States)

    1993-04-01

    Over the past two years, ICRF heating experiments have been performed on TFTR in the hydrogen minority heating regime with power levels reaching 11.2 MW in helium-4 majority plasmas and 8.4 MW in deuterium majority plasmas. For these power levels, the minority hydrogen ions, which comprise typically less than 10% of the total electron density, evolve into la very energetic, anisotropic non-Maxwellian distribution. Indeed, the excess perpendicular stored energy in these plasmas associated with the energetic minority tail ions is often as high as 25% of the total stored energy, as inferred from magnetic measurements. Enhanced losses of 0.5 MeV protons consistent with the presence of an energetic hydrogen component have also been observed. In ICRF heating experiments on JET at comparable and higher power levels and with similar parameters, it has been suggested that finite banana width effects have a noticeable effect on the ICRF power deposition. In particular, models indicate that finite orbit width effects lead to a reduction in the total stored energy and of the tail energy in the center of the plasma, relative to that predicted by the zero banana width models. In this paper, detailed comparisons between the calculated ICRF power deposition profiles and experimentally measured quantities will be presented which indicate that significant deviations from the zero banana width models occur even for modest power levels (P{sub rf} {approximately} 6 MW) in the TFTR experiments.

  4. Metal foam sandwich structure as a high temperature heat exchanger

    Energy Technology Data Exchange (ETDEWEB)

    Salimijazi, H.R.; Pershin, L.; Coyle, T.W.; Mostaghimi, J.; Chandra, S. [Toronto Univ., ON (Canada)

    2008-07-01

    Nickel-based superalloys can be used at temperatures up to 1050 C in air. Superalloy open cell foam sheets with skin layers plasma sprayed on both sides can be used as high temperature heat exchangers provided that the two deposited skins are dense and well adhered to the open cell foam. In this study alloy 625 skins were deposited on each side of a sheet of metal foam by APS and HVOF to form a sandwich structure. Two densities of open cell foams, 20 and 10 pores per linear inch (ppi), were used in this study as the core. The initial Ni foam was converted to an alloy composition by plasma spraying aluminum and chromium on the foam's struts with subsequent diffusion/solutionizing heat treatments before the alloy 625 skins were deposited. The microstructure of the coatings and the interface between the struts and skins was investigated. A layer of Ni-Al alloy was formed near the surface of the struts as a result of the heat treatment. The foam struts were imbedded more deeply into the coatings deposited by HVOF than the coatings deposited by APS. (orig.)

  5. Fatigue in a heat treatable high silicon containing aluminium alloy

    Science.gov (United States)

    González, J. A.; Talamantes-Silva, J.; Valtierra, S.; Colás, Rafael

    2017-05-01

    The use of cast aluminium alloys in automobiles contributes to reductions in weight and fuel consumption without impairing the safety for the occupants or the performance of the car. Most of the alloys used are heat treatable hypoeutectic Al-Si alloys, which have the drawback of exhibiting low wear resistance. So industry relies in wear resistant alloys, such as grey iron, for the liners of the combustion chambers in engine blocks, which increase the weight of the engine. Therefore, it is of interest to cast high silicon containing alloys into engine components that are able to resist wear while maintaining the mechanical properties required by the components. This work presents the result of the work carried out in a high silicon containing heat treatable aluminium alloy as it is subjected to high cycle fatigue. The alloy was prepared and cast in ingots designed to promote one dimensional solidification gradient to obtain samples to study the high cycle fatigue. The material was machined into hour-glass specimens that were tested at room temperature in a servohydraulic machine under load control following the stair case method. The results show that the resistance to fatigue depends on the microstructure of the sample, as the fatigue cracks originate in pores close to the surface of the sample and propagate through the eutectic aggregate. The results from this work are compared with those from previously obtained with hypoeutectic alloys.

  6. High-capacity, transient retention of direction-of-motion information for multiple moving objects.

    Science.gov (United States)

    Shooner, Christopher; Tripathy, Srimant P; Bedell, Harold E; Ogmen, Haluk

    2010-06-01

    The multiple-object tracking paradigm (MOT) has been used extensively for studying dynamic visual attention, but the basic mechanisms which subserve this capability are as yet unknown. Among the unresolved issues surrounding MOT are the relative importance of motion (as opposed to positional) information and the role of various memory mechanisms. We sought to quantify the capacity and dynamics for retention of direction-of-motion information when viewing a multiple-object motion stimulus similar to those used in MOT. Observers viewed three to nine objects in random linear motion and then reported motion direction after motion ended. Using a partial-report paradigm and varying the parameters of set size and time of retention, we found evidence for two complementary memory systems, one transient with high capacity and a second sustained system with low capacity. For the transient high-capacity memory, retention capacity was equally high whether object motion lasted several seconds or a fraction of a second. Also, a graded deterioration in performance with increased set size lends support to a flexible-capacity theory of MOT.

  7. 76 FR 30753 - Notice of Availability of a Record of Decision (ROD) for the Proposed Honolulu High-Capacity...

    Science.gov (United States)

    2011-05-26

    ... Honolulu High-Capacity Transit Corridor Project (HHCTCP) Segment at Honolulu International Airport (HNL... for the construction and operation of a 3-mile segment at HNL for the proposed Honolulu High-Capacity...-mile project in January 2011. The Project would provide a high-capacity rapid transit service in the...

  8. 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...... are calculated using an energy system model which includes power plants, heat pumps and district heating consumption profiles. The model is developed with focus on accurate representation of the performance of the units in different locations and operating modes. The model can assist in investment decisions...... 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...

  9. High-heat-flux sensor calibration using calorimetry

    Science.gov (United States)

    Ballestrín, J.; Estrada, C. A.; Rodríguez-Alonso, M.; Pérez-Rábago, C.; Langley, L. W.; Barnes, A.

    2004-08-01

    This paper demonstrates a calorimetric procedure for calibrating high-heat-flux sensors. The results are in agreement with calibrations obtained using black-body radiation. However, the proposed method has the potential of being more accurate than traditional approaches. This new procedure calibrates sensors to measure correctly under conditions of concentrated solar radiation. At present, the thermal balance calibration technique in the laboratory is limited to solar irradiances of approximately 100 kW m-2. The next step is to demonstrate this methodology to higher irradiances under non-laboratory conditions in the CIEMAT solar furnace at Plataforma Solar de Almería.

  10. Study of Volumetrically Heated Ultra-High Energy Density Plasmas

    Energy Technology Data Exchange (ETDEWEB)

    Rocca, Jorge J. [Colorado State Univ., Fort Collins, CO (United States)

    2016-10-27

    Heating dense matter to millions of degrees is important for applications, but requires complex and expensive methods. The major goal of the project was to demonstrate using a compact laser the creation of a new ultra-high energy density plasma regime characterized by simultaneous extremely high temperature and high density, and to study it combining experimental measurements and advanced simulations. We have demonstrated that trapping of intense femtosecond laser pulses deep within ordered nanowire arrays can heat near solid density matter into a new ultra hot plasma regime. Extreme electron densities, and temperatures of several tens of million degrees were achieved using laser pulses of only 0.5 J energy from a compact laser. Our x-ray spectra and simulations showed that extremely highly ionized plasma volumes several micrometers in depth are generated by irradiation of gold and Nickel nanowire arrays with femtosecond laser pulses of relativistic intensities. We obtained extraordinarily high degrees of ionization (e.g. we peeled 52 electrons from gold atoms, and up to 26 electrons from nickel atoms). In the process we generated Gigabar pressures only exceeded in the central hot spot of highly compressed thermonuclear fusion plasmas.. The plasma created after the dissolved wires expand, collide, and thermalize, is computed to have a thermal energy density of 0.3 GJ cm-3 and a pressure of 1-2 Gigabar. These are pressures only exceeded in highly compressed thermonuclear fusion plasmas. Scaling these results to higher laser intensities promises to create plasmas with temperatures and pressures exceeding those in the center of the sun.

  11. Generation Capacity Investments and High Levels of Renewables. The Impact of a German Capacity Market on Northwest Europe. Discussion paper

    Energy Technology Data Exchange (ETDEWEB)

    Ozdemir, O.; De Joode, J.; Koutstaal, P.R.; Van Hout, M. [ECN Policy Studies, Amsterdam (Netherlands)

    2013-05-15

    Presently, Northwest European centralised electricity markets are designed as 'energy-only' markets. In an energy-only market, the price received for electricity produced is set by the marginal generation unit. Potentially, the designs of these markets could leave the owners of these units with 'missing money': i.e. money that is required to recover investment cost. Further, increasing penetration of renewables could exacerbate this problem. Of all the different options available to tackle the 'missing money' problem, capacity mechanisms have attracted most of the attention in recent policy debates in Europe. This paper contributes to ongoing policy discussions by providing a quantitative analysis of the phenomena of 'missing money' and capacity mechanisms in Northwest Europe. Our analysis shows that in the case of energy-only markets with a much higher penetration of intermittent electricity sources such as wind and solar PV, the 'missing money' problem may be aggravated, because operating hours for peak and mid-merit order capacity will be considerably reduced. Furthermore, unilateral introduction of capacity mechanisms in integrated electricity markets can have considerable impacts on cross-border electricity flows and investment decisions. Stand-alone introduction of a capacity market in Germany will likely result in higher investments in Germany at the expense of lower investments outside Germany and an increase in net exports from Germany. A possible advantage of a unilateral capacity mechanism in Germany may be a reduction in super-peak prices in the larger market area. Thus, neighbouring countries may have the possibility to free ride on the increase in flexible capacity in Germany. However, this advantage is conditional and depends on sufficient availability of interconnection capacity necessary to be able to use this reserve capacity. Otherwise, security of supply might be more at risk if the German

  12. A reduced core to skin temperature gradient, not a critical core temperature, affects aerobic capacity in the heat.

    Science.gov (United States)

    Cuddy, John S; Hailes, Walter S; Ruby, Brent C

    2014-07-01

    The purpose of this study was to determine the impact of the core to skin temperature gradient during incremental running to volitional fatigue across varying environmental conditions. A secondary aim was to determine if a "critical" core temperature would dictate volitional fatigue during running in the heat. 60 participants (n=49 male, n=11 female; 24±5 yrs, 177±11 cm, 75±13 kg) completed the study. Participants were uniformly stratified into a specific exercise temperature group (18 °C, 26 °C, 34 °C, or 42 °C) based on a 3-mile run performance. Participants were equipped with core and chest skin temperature sensors and a heart rate monitor, entered an environmental chamber (18 °C, 26 °C, 34 °C, or 42 °C), and rested in the seated position for 10 min before performing a walk/run to volitional exhaustion. Initial treadmill speed was 3.2 km h(-1) with a 0% grade. Every 3 min, starting with speed, speed and grade increased in an alternating pattern (speed increased by 0.805 km h(-1), grade increased by 0.5%). Time to volitional fatigue was longer for the 18 °C and 26 °C group compared to the 42 °C group, (58.1±9.3 and 62.6±6.5 min vs. 51.3±8.3 min, respectively, pskin gradient for the 18 °C and 26 °C groups was larger compared to 42 °C group (halfway: 2.6±0.7 and 2.0±0.6 vs. 1.3±0.5 for the 18 °C, 26 °C and 42 °C groups, respectively; finish: 3.3±0.7 and 3.5±1.1 vs. 2.1±0.9 for the 26 °C, 34 °C, and 42 °C groups, respectively, ptemperature and heart rate response during the exercise trials. The current data demonstrate a 13% and 22% longer run time to exhaustion for the 18 °C and 26 °C group, respectively, compared to the 42 °C group despite no differences in beginning and ending core temperatures or baseline 3-mile run time. This capacity difference appears to result from a magnified core to skin gradient via an environmental temperature advantageous to convective heat loss, and in part from an increased sweat rate. Copyright

  13. Electric heating provides a high level of home comfort - economically

    Energy Technology Data Exchange (ETDEWEB)

    Haapakoski, M.

    1997-11-01

    Research and development at IVO in the area of electric heating boasts a tradition going back almost thirty years. Research aimed at further progress is continuing. IVO and power companies launched the `Electrically heated houses of the century` project four years ago. The first results show that electric heating continues to be very competitive with other heating systems. It is an economical way of heating the home and it also increases the comfort of those living there

  14. Reproducibility of High-Q SRF Cavities by High Temperature Heat Treatment

    Energy Technology Data Exchange (ETDEWEB)

    Dhakal, Pashupati [JLAB; Ciovati, Gianluigi [JLAB; Kneisel, Peter [JLAB; Myneni, Ganapati Rao [JLAB

    2014-07-01

    Recent work on high-temperature (> 600 °C) heat treatment of ingot Nb cavities in a customized vacuum furnace for several hours showed the possibility of achieving Q0-values of up to ~5×1010 at 2.0 K, 1.5 GHz and accelerating gradients of ~20 MV/m. This contribution presents results on further studies of the heat treatment process to produce cavities with high Q0 values for continuous-wave accelerator application. Single-cell cavities of different Nb purity have been processed through few cycles of heat-treatments and chemical etching. Measurements of Q0 as a function of temperature at low RF field and of Q0 as a function of the RF field at or below 2.0 K have been made after each treatment. Measurements by TOF-SIMS of the impurities depth profiles were made on samples heat treated with the cavities.

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

    OpenAIRE

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

    2009-01-01

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

  16. Heat transfer issues in high-heat-load synchrotron x-ray beams

    Energy Technology Data Exchange (ETDEWEB)

    Khounsary, A.M.; Mills, D.M.

    1994-09-01

    In this paper, a short description of the synchrotron radiation x-ray sources and the associated power loads is given, followed by a brief description of typical synchrotron components and their heat load. It is emphasized that the design goals for most of these components is to limit (a) temperature, (b) stresses, or (c) strains in the system. Each design calls for a different geometry, material selection, and cooling scheme. Cooling schemes that have been utilized so far are primarily single phase and include simple macrochannel cooling, microchannel cooling, contact cooling, pin-post cooling, porous-flow cooling, jet cooling, etc. Water, liquid metals, and various cryogenic coolants have been used. Because the trend in x-ray beam development is towards brighter (i.e., more powerful) beams and assuming that no radical changes in the design of x-ray generating machines occurs in the next few years, it is fair to state that the utilization of various effective cooling schemes and, in particular, two-phase flow (e.g., subcooled boiling) warrants further investigation. This, however, requires a thorough examination of stability and reliability of two-phase flows for high-heat-flux components operating in ultrahigh vacuum with stringent reliability requirements.

  17. High Volumetric Capacity Three-Dimensionally Sphere-Caged Secondary Battery Anodes.

    Science.gov (United States)

    Liu, Jinyun; Chen, Xi; Kim, Jinwoo; Zheng, Qiye; Ning, Hailong; Sun, Pengcheng; Huang, Xingjiu; Liu, Jinhuai; Niu, Junjie; Braun, Paul V

    2016-07-13

    High volumetric energy density secondary batteries are important for many applications, which has led to considerable efforts to replace the low volumetric capacity graphite-based anode common to most Li-ion batteries with a higher energy density anode. Because most high capacity anode materials expand significantly during charging, such anodes must contain sufficient porosity in the discharged state to enable the expansion, yet not excess porosity, which lowers the overall energy density. Here, we present a high volumetric capacity anode consisting of a three-dimensional (3D) nanocomposite formed in only a few steps which includes both a 3D structured Sn scaffold and a hollow Sn sphere within each cavity where all the free Sn surfaces are coated with carbon. The anode exhibits a high volumetric capacity of ∼1700 mA h cm(-3) over 200 cycles at 0.5C, and a capacity greater than 1200 mA h cm(-3) at 10C. Importantly, the anode can even be formed into a commercially relevant ∼100 μm thick form. When assembled into a full cell the anode shows a good compatibility with a commercial LiMn2O4 cathode. In situ TEM observations confirm the electrode design accommodates the necessary volume expansion during lithiation.

  18. Flexible Lithium-Ion Batteries with High Areal Capacity Enabled by Smart Conductive Textiles.

    Science.gov (United States)

    Ha, Sung Hoon; Shin, Kyu Hang; Park, Hae Won; Lee, Yun Jung

    2018-02-05

    Increasing demand for flexible devices in various applications, such as smart watches, healthcare, and military applications, requires the development of flexible energy-storage devices, such as lithium-ion batteries (LIBs) with high flexibility and capacity. However, it is difficult to ensure high capacity and high flexibility simultaneously through conventional electrode preparation processes. Herein, smart conductive textiles are employed as current collectors for flexible LIBs owing to their inherent flexibility, fibrous network, rough surface for better adhesion, and electrical conductivity. Conductivity and flexibility are further enhanced by nanosizing lithium titanate oxide (LTO) and lithium iron phosphate (LFP) active materials, and hybridizing them with a flexible 2D graphene template. The resulting LTO/LFP full cells demonstrate high areal capacity and flexibility with tolerance to mechanical fatigue. The battery achieves a capacity of 1.2 mA h cm-2 while showing excellent flexibility. The cells demonstrate stable open circuit voltage retention under repeated flexing for 1000 times at a bending radius of 10 mm. The discharge capacity of the unflexed battery is retained in cells subjected to bending for 100 times at bending radii of 30, 20, and 10 mm, respectively, confirming that the suggested electrode configuration successfully prevents structural damage (delamination or cracking) upon repeated deformation. © 2018 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  19. 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.

  20. A reversible dendrite-free high-areal-capacity lithium metal electrode

    Science.gov (United States)

    Wang, Hui; Matsui, Masaki; Kuwata, Hiroko; Sonoki, Hidetoshi; Matsuda, Yasuaki; Shang, Xuefu; Takeda, Yasuo; Yamamoto, Osamu; Imanishi, Nobuyuki

    2017-04-01

    Reversible dendrite-free low-areal-capacity lithium metal electrodes have recently been revived, because of their pivotal role in developing beyond lithium ion batteries. However, there have been no reports of reversible dendrite-free high-areal-capacity lithium metal electrodes. Here we report on a strategy to realize unprecedented stable cycling of lithium electrodeposition/stripping with a highly desirable areal-capacity (12 mAh cm-2) and exceptional Coulombic efficiency (>99.98%) at high current densities (>5 mA cm-2) and ambient temperature using a diluted solvate ionic liquid. The essence of this strategy, that can drastically improve lithium electrodeposition kinetics by cyclic voltammetry premodulation, lies in the tailoring of the top solid-electrolyte interphase layer in a diluted solvate ionic liquid to facilitate a two-dimensional growth mode. We anticipate that this discovery could pave the way for developing reversible dendrite-free metal anodes for sustainable battery chemistries.

  1. Robo-line storage: Low latency, high capacity storage systems over geographically distributed networks

    Science.gov (United States)

    Katz, Randy H.; Anderson, Thomas E.; Ousterhout, John K.; Patterson, David A.

    1991-01-01

    Rapid advances in high performance computing are making possible more complete and accurate computer-based modeling of complex physical phenomena, such as weather front interactions, dynamics of chemical reactions, numerical aerodynamic analysis of airframes, and ocean-land-atmosphere interactions. Many of these 'grand challenge' applications are as demanding of the underlying storage system, in terms of their capacity and bandwidth requirements, as they are on the computational power of the processor. A global view of the Earth's ocean chlorophyll and land vegetation requires over 2 terabytes of raw satellite image data. In this paper, we describe our planned research program in high capacity, high bandwidth storage systems. The project has four overall goals. First, we will examine new methods for high capacity storage systems, made possible by low cost, small form factor magnetic and optical tape systems. Second, access to the storage system will be low latency and high bandwidth. To achieve this, we must interleave data transfer at all levels of the storage system, including devices, controllers, servers, and communications links. Latency will be reduced by extensive caching throughout the storage hierarchy. Third, we will provide effective management of a storage hierarchy, extending the techniques already developed for the Log Structured File System. Finally, we will construct a protototype high capacity file server, suitable for use on the National Research and Education Network (NREN). Such research must be a Cornerstone of any coherent program in high performance computing and communications.

  2. Capacity Loss Studies on High Capacity Li-ion Cells for the Orbiter Advanced Hydraulic Power System

    Science.gov (United States)

    Jeevarajan, Judith A.; Irlbeck, Bradley W.

    2004-01-01

    Contents include the following: Introduction. Physical and electrochemical characteristics. Performance evaluation. Rate performance. Internal resistance. Performance at different temperatures. Safety evaluation. Overcharge. Overdischarge. External short. Simulated internal short. Heat-to-vent. Vibration. Drop rest. Vent and burst pressure.

  3. 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.

  4. E- and W-band high-capacity hybrid fiber-wireless link

    DEFF Research Database (Denmark)

    Vegas Olmos, Juan José; Pang, Xiaodan; Tafur Monroy, Idelfonso

    2014-01-01

    In this paper we summarize the work conducted in our group in the area of E- and W-band optical high-capacity fiber-wireless links. We present performance evaluations of E- and W-band mm-wave signal generation using photonic frequency upconversion employing both VCSELs and ECLs, along with transm......In this paper we summarize the work conducted in our group in the area of E- and W-band optical high-capacity fiber-wireless links. We present performance evaluations of E- and W-band mm-wave signal generation using photonic frequency upconversion employing both VCSELs and ECLs, along...

  5. Comprehensive assessment of geographic variation in heat tolerance and hardening capacity in populations of Drosophila melanogaster from eastern Australia

    DEFF Research Database (Denmark)

    Sgro, Carla M.; Overgaard, Johannes; Kristensen, Torsten Nygård

    2010-01-01

    We examined latitudinal variation in adult and larval heat tolerance in Drosophila melanogaster from eastern Australia. Adults were assessed using static and ramping assays. Basal and hardened static heat knockdown time showed significant linear clines; heat tolerance increased towards the tropics......, particularly for hardened flies, suggesting that tropical populations have a greater hardening response. A similar pattern was evident for ramping heat knockdown time at 0.06 degrees C min-1 increase. There was no cline for ramping heat knockdown temperature (CTmax) at 0.1 degrees C min-1 increase. Acute...

  6. Determining the Optimal Capacities of Renewable-Energy-Based Energy Conversion Systems for Meeting the Demands of Low-Energy District Heating, Electricity, and District Cooling

    DEFF Research Database (Denmark)

    Tol, Hakan; Svendsen, Svend; Dincer, Ibrahim

    2015-01-01

    This chapter presents a method for determining the optimal capacity of a renewable-energy-based energy conversion system for meeting the energy requirements of a given district as considered on a monthly basis, with use of a low-energy district heating system operating at a low temperature, as low......, and the other for the Greater Toronto Area. Various climate conditions of the case areas in question caused different observations of nominal capacities for the energy conversion systems considered with single-production and multi-production based on different renewable energy sources....

  7. Shear Capacity and Failure Behavior of Steel-Reinforced High Ductile Concrete Beams

    Directory of Open Access Journals (Sweden)

    Mingke Deng

    2015-01-01

    Full Text Available The shear behavior of six high ductile fiber reinforced concrete (HDC beams is studied to investigate the influence of shear-span ratio and HDC mechanical property on the improvement of the shear failure mode and shear capacity of short beams. Four steel-reinforced high ductile concrete beams (SHDC beams with different shear span ratios are tested under concentrated load at midspan. To study the effect of stirrups and steel on the shear capacity of short beams, two additional specimens without steel but one including stirrups are investigated. The main aspects of SHDC beams are discussed in detail, such as failure mode, deformability, and shear capacity. Test results show that the SHDC short beams keep high residual bearing capacity and great integrity when suffering from large deformation. It is revealed that HDC increased the shear ductility and improved the shear failure mode of short beams. A comparison with the shear equations of Chinese YB9082-2006 shows that the Chinese Code equation provides conservative estimation for HDC beams. This study proposes modifications to the equation for predicting the shear capacity of HDC beams.

  8. Effect of variable thermal conductivity and specific heat capacity on the calculation of the critical metal hydride thickness for Ti1.1CrMn

    DEFF Research Database (Denmark)

    Mazzucco, Andrea; Rokni, Masoud

    2014-01-01

    model is applied to the metal hydride system, with Ti 1.1 CrMn as the absorbing alloy, to predict the weight fraction of absorbed hydrogen and solid bed temperat ure . Dependencies of thermal conductivity and specific heat capacity upon pressure and hydrogen content respectively , are accounted for...... with activated powder and embedded heat exchanger makes difficult to set up experimental facilities. Trustable simulation models that can address the system ́s performances to a particular design are then a funda mental step to be taken prior any experimental setup. This study considers a detailed 1D fueling...

  9. Graphitized Carbon Fibers as Multifunctional 3D Current Collectors for High Areal Capacity Li Anodes.

    Science.gov (United States)

    Zuo, Tong-Tong; Wu, Xiong-Wei; Yang, Chun-Peng; Yin, Ya-Xia; Ye, Huan; Li, Nian-Wu; Guo, Yu-Guo

    2017-08-01

    The Li metal anode has long been considered as one of the most ideal anodes due to its high energy density. However, safety concerns, low efficiency, and huge volume change are severe hurdles to the practical application of Li metal anodes, especially in the case of high areal capacity. Here it is shown that that graphitized carbon fibers (GCF) electrode can serve as a multifunctional 3D current collector to enhance the Li storage capacity. The GCF electrode can store a huge amount of Li via intercalation and electrodeposition reactions. The as-obtained anode can deliver an areal capacity as high as 8 mA h cm(-2) and exhibits no obvious dendritic formation. In addition, the enlarged surface area and porous framework of the GCF electrode result in lower local current density and mitigate high volume change during cycling. Thus, the Li composite anode displays low voltage hysteresis, high plating/stripping efficiency, and long lifespan. The multifunctional 3D current collector promisingly provides a new strategy for promoting the cycling lifespan of high areal capacity Li anodes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Glass Strengthening via High-Intensity Plasma-Arc Heating

    Energy Technology Data Exchange (ETDEWEB)

    Wereszczak, Andrew A [ORNL; Harper, David C [ORNL; Duty, Chad E [ORNL; Patel, P [U.S. Army research Laboratory, Adelphi, MD

    2010-01-01

    The use of a high-intensity plasma-arc lamp was used to irradiate the surface of soda-lime silicate glass tiles to determine if an increase in strength could be achieved. The lamp had a power density of 3500 W/cm2, a processing area of 1 cm x 10 cm, irradiated near-infrared heating at a wavelength between 0.2 1.4 m, and was controlled to unidirectionally sweep across 50-mm-square tiles at a constant speed of 8 mm/s. Ring-on-ring (RoR) equibiaxial flexure and 4 pt uni-directional flexure testings of entire tiles were used to measure and compare failure stress distributions of treated and untreated glass. Even with non-optimized processing conditions, RoR failure stress increased by approximately 25% and the 4 pt bend failure stress increased by approximately 65%. Strengthening was due to a fire-polishing-like mechanism. The arc-lamp heat-treatment caused the location of the strength-limiting flaws in the 4-pt-bend tiles to change; namely, failure initiation occurred on the gage section surface for the treated glass whereas it occurred at a gage section edge for the untreated. Arc-lamp heat-treatment is attractive not only because it provides strengthening, but because it can (non-contact) process large amounts of glass quickly and inexpensively, and is a process that either a glass manufacturer or end-user can readily employ.

  11. Process Heat Exchanger Options for Fluoride Salt High Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Piyush Sabharwall; Eung Soo Kim; Michael McKellar; Nolan Anderson

    2011-04-01

    The work reported herein is a significant intermediate step in reaching the final goal of commercial-scale deployment and usage of molten salt as the heat transport medium for process heat applications. The primary purpose of this study is to aid in the development and selection of the required heat exchanger for power production and process heat application, which would support large-scale deployment.

  12. Process Heat Exchanger Options for the Advanced High Temperature Reactor

    Energy Technology Data Exchange (ETDEWEB)

    Piyush Sabharwall; Eung Soo Kim; Michael McKellar; Nolan Anderson

    2011-06-01

    The work reported herein is a significant intermediate step in reaching the final goal of commercial-scale deployment and usage of molten salt as the heat transport medium for process heat applications. The primary purpose of this study is to aid in the development and selection of the required heat exchanger for power production and process heat application, which would support large-scale deployment.

  13. Hollow Carbon Nanofiber-Encapsulated Sulfur Cathodes for High Specific Capacity Rechargeable Lithium Batteries

    KAUST Repository

    Zheng, Guangyuan

    2011-10-12

    Sulfur has a high specific capacity of 1673 mAh/g as lithium battery cathodes, but its rapid capacity fading due to polysulfides dissolution presents a significant challenge for practical applications. Here we report a hollow carbon nanofiber-encapsulated sulfur cathode for effective trapping of polysulfides and demonstrate experimentally high specific capacity and excellent electrochemical cycling of the cells. The hollow carbon nanofiber arrays were fabricated using anodic aluminum oxide (AAO) templates, through thermal carbonization of polystyrene. The AAO template also facilitates sulfur infusion into the hollow fibers and prevents sulfur from coating onto the exterior carbon wall. The high aspect ratio of the carbon nanofibers provides an ideal structure for trapping polysulfides, and the thin carbon wall allows rapid transport of lithium ions. The small dimension of these nanofibers provides a large surface area per unit mass for Li2S deposition during cycling and reduces pulverization of electrode materials due to volumetric expansion. A high specific capacity of about 730 mAh/g was observed at C/5 rate after 150 cycles of charge/discharge. The introduction of LiNO3 additive to the electrolyte was shown to improve the Coulombic efficiency to over 99% at C/5. The results show that the hollow carbon nanofiber-encapsulated sulfur structure could be a promising cathode design for rechargeable Li/S batteries with high specific energy. © 2011 American Chemical Society.

  14. Enhanced Dissociation of Intact Proteins with High Capacity Electron Transfer Dissociation.

    Science.gov (United States)

    Riley, Nicholas M; Mullen, Christopher; Weisbrod, Chad R; Sharma, Seema; Senko, Michael W; Zabrouskov, Vlad; Westphall, Michael S; Syka, John E P; Coon, Joshua J

    2016-03-01

    Electron transfer dissociation (ETD) is a valuable tool for protein sequence analysis, especially for the fragmentation of intact proteins. However, low product ion signal-to-noise often requires some degree of signal averaging to achieve high quality MS/MS spectra of intact proteins. Here we describe a new implementation of ETD on the newest generation of quadrupole-Orbitrap-linear ion trap Tribrid, the Orbitrap Fusion Lumos, for improved product ion signal-to-noise via ETD reactions on larger precursor populations. In this new high precursor capacity ETD implementation, precursor cations are accumulated in the center section of the high pressure cell in the dual pressure linear ion trap prior to charge-sign independent trapping, rather than precursor ion sequestration in only the back section as is done for standard ETD. This new scheme increases the charge capacity of the precursor accumulation event, enabling storage of approximately 3-fold more precursor charges. High capacity ETD boosts the number of matching fragments identified in a single MS/MS event, reducing the need for spectral averaging. These improvements in intra-scan dynamic range via reaction of larger precursor populations, which have been previously demonstrated through custom modified hardware, are now available on a commercial platform, offering considerable benefits for intact protein analysis and top down proteomics. In this work, we characterize the advantages of high precursor capacity ETD through studies with myoglobin and carbonic anhydrase.

  15. RECUPERATOR FOR HIGH-TEMPERATURE HEATING OF BLOWING

    Directory of Open Access Journals (Sweden)

    S. L. Rovin

    2011-01-01

    Full Text Available Heat recovery is an effective method of shortening specific energy consumption. New constructions of recuperators for heating and cupola furnaces have been designed and successfully introduced. Two-stage recuperator with computer control providing blast heating up to 600 °C and reducing fuel consumption by 30% is of special interest.

  16. High Thermal Conductivity Polymer Composites for Low Cost Heat Exchangers

    Energy Technology Data Exchange (ETDEWEB)

    None

    2017-08-01

    This factsheet describes a project that identified and evaluated commercially available and state-of-the-art polymer-based material options for manufacturing industrial and commercial non-metallic heat exchangers. A heat exchanger concept was also developed and its performance evaluated with heat transfer modeling tools.

  17. Ion association in N-methylpyrrolidone and the N-methylpyrrolidone-water mixed solvent from data on heat capacity and density of solutions

    Science.gov (United States)

    Solov'ev, S. N.; Novikov, A. N.

    2012-06-01

    Association constants for solutions of electrolytes in N-methylpyrrolidone (MP) and the MP-water mixed solvent at 298.15 K are calculated. It is shown that, over a wide range of concentrations, concentration dependences of apparent molar heat capacities and apparent molar volumes of the electrolytes in MP and MP-water mixtures are described adequately in terms of equilibria between ions and ion pairs of a single type in the solution.

  18. Public utility Rosenheim enlarge the capacity of district heating by means of return temperatures. District heating transmission stations with cascade; Stadtwerke Rosenheim erweitern FW-Kapazitaet durch niedrigere Ruecklauftemperaturen. Fernwaermeuebergabestation mit Kaskade

    Energy Technology Data Exchange (ETDEWEB)

    Bruehl, Goetz; Bielmeier, Reinhard; Neugebauer, Horst [Stadtwerke Rosenheim (Germany); Weinmann, Edwin [Planungsbuero Weinmann, Muenchen (Germany); Planungsbuero Weinmann, Wielenbach (Germany)

    2012-12-15

    In most cases heating systems, drinking water heaters and circulation heaters are connected in parallel. This arrangement often results in too high return temperatures. In order to keep down the return temperature all the year, the public utility Rosenheim developed a cascaded high-efficiency district heating transmission station in cooperation with two partners. Due to the series connection of the heat exchangers for the hot water circulation, the heating system and the drinking water heaters in continuous flow, not only permanently lower return temperatures are achieved, but also the consumption of the power of pumps is lowered as well as the hygiene requirements to drinking water is improved.

  19. A High Capacity, Good Safety and Low Cost Na2FeSiO4-Based Cathode for Rechargeable Sodium-Ion Battery.

    Science.gov (United States)

    Guan, Wenhao; Pan, Bin; Zhou, Peng; Mi, Jinxiao; Zhang, Dan; Xu, Jiacheng; Jiang, Yinzhu

    2017-07-12

    Rechargeable sodium-ion batteries (SIBs) are receiving intense interest because the resource abundance of sodium and its lithium-like chemistry make them low cost alternatives to the prevailing lithium-ion batteries in large-scale energy storage devices. Two typical classes of materials including transition metal oxides and polyanion compounds have been under intensive investigation as cathodes for SIBs; however, they are still limited to poor stability or low capacity of the state-of-art. Herein, we report a low cost carbon-coated Na2FeSiO4 with simultaneous high capacity and good stability, owing to the highly pure Na-rich triclinic phase and the carbon-incorporated three-dimensional network morphology. The present carbon-coated Na2FeSiO4 demonstrates the highest reversible capacity of 181.0 mAh g(-1) to date with multielectron redox reaction that occurred among various polyanion-based SIBs cathodes, which achieves a close-to-100% initial Coulombic efficiency and a stable cycling with 88% capacity retention up to 100 cycles. In addition, such an electrode shows excellent stability either charged at a high voltage of 4.5 V or heated up to 800 °C. The present work might open up the possibility for developing high capacity, good safety and low cost polyanion-based cathodes for rechargeable SIBs.

  20. High Magnetic Field Processing - A Heat-Free Heat Treating Method

    Energy Technology Data Exchange (ETDEWEB)

    Ludtka, Gerard Michael [ORNL; Ludtka, Gail Mackiewicz- [ORNL; Wilgen, John B [ORNL; Kenik, Edward A [ORNL; Parish, Chad M [ORNL; Rios, Orlando [ORNL; Rogers, Hiram [ORNL; Manuel, Michele [University of Florida, Gainesville; Kisner, Roger A [ORNL; Watkins, Thomas R [ORNL; Murphy, Bart L [ORNL

    2012-08-01

    The High and Thermal Magnetic Processing/Electro-magnetic Acoustic Transducer (HTMP/EMAT) technology has been shown to be an enabling disruptive materials processing technology, that can achieve significant improvements in microstructure and consequently material performance beyond that achievable through conventional processing, and will lead to the next generation of advanced performance structural and functional materials. HTMP exposure increased the reaction kinetics enabling refinement of microstructural features such as finer martensite lath size, and finer, more copious, homogeneous dispersions of strengthening carbides leading to combined strength and toughness improvements in bainitic steels. When induction heating is applied in a high magnetic field environment, the induction heating coil is configured so that high intensity acoustic/ultrasonic treatment occurs naturally. The configuration results in a highly effective electromagnetic acoustical transducer (EMAT). HTMP combined with applying high-field EMAT, produce a non-contact ultrasonic treatment that can be used to process metal alloys in either the liquid state resulting in significant microstructural changes over conventional processing. Proof-of-principle experiments on cast irons resulted in homogeneous microstructures in small castings along with improved casting surface appearance. The experiment showed that by exposing liquid metal to the non-contact acoustic/ultrasonic processing technology developed using HMFP/EMAT wrought-like microstructures were developed in cast components. This Energy Intensive Processes (EIP) project sponsored by the DOE EERE Advanced Manufacturing Office (AMO) demonstrated the following: (1) The reduction of retained austenite in high carbon/high alloy steels with an ambient temperature HTMP process, replacing either a cryogenic or double tempering thermal process normally employed to accomplish retained austenite transformation. HTMP can be described as a 'heat

  1. Spin heat capacity of monolayer and AB-stacked bilayer MoS2 in the presence of exchange magnetic field

    Science.gov (United States)

    Hoi, Bui Dinh; Yarmohammadi, Mohsen; Mirabbaszadeh, Kavoos

    2017-04-01

    Dirac theory and Green's function technique are carried out to compute the spin dependent band structures and corresponding electronic heat capacity (EHC) of monolayer (ML) and AB-stacked bilayer (BL) molybdenum disulfide (MoS2) two-dimensional (2D) crystals. We report the influence of induced exchange magnetic field (EMF) by magnetic insulator substrates on these quantities for both structures. The spin-up (down) subband gaps are shifted with EMF from conduction (valence) band to valence (conduction) band at both Dirac points in the ML because of the spin-orbit coupling (SOC) which leads to a critical EMF in the K point and EHC returns to its initial states for both spins. In the BL case, EMF results split states and the decrease (increase) behavior of spin-up (down) subband gaps has been observed at both K and K‧ valleys which is due to the combined effect of SOC and interlayer coupling. For low and high EMFs, EHC of BL MoS2 does not change for spin-up subbands while increases for spin-down subbands.

  2. Digital pre-compensation techniques enabling high-capacity bandwidth variable transponders

    Science.gov (United States)

    Napoli, Antonio; Berenguer, Pablo Wilke; Rahman, Talha; Khanna, Ginni; Mezghanni, Mahdi M.; Gardian, Lennart; Riccardi, Emilio; Piat, Anna Chiadò; Calabrò, Stefano; Dris, Stefanos; Richter, André; Fischer, Johannes Karl; Sommerkorn-Krombholz, Bernd; Spinnler, Bernhard

    2018-02-01

    Digital pre-compensation techniques are among the enablers for cost-efficient high-capacity transponders. In this paper we describe various methods to mitigate the impairments introduced by state-of-the-art components within modern optical transceivers. Numerical and experimental results validate their performance and benefits.

  3. Supporting Leadership Development: An Examination of High School Principals' Efforts to Develop Leaders' Personal Capacities

    Science.gov (United States)

    Huggins, Kristin Shawn; Klar, Hans W.; Hammonds, Hattie L.; Buskey, Frederick C.

    2016-01-01

    In this article, we report findings from an exploratory, qualitative study in which we used a constructivist lens to examine how two high school principals endeavored to develop the personal capacities of teachers and other leaders in their schools. We collected data from semistructured interviews with the principals and three other leaders from…

  4. Addition of titanium as a potential catalyst for a high-capacity hydrogen storage medium

    NARCIS (Netherlands)

    Zuliani, F.; Baerends, E.J.

    2008-01-01

    In recent years there has been increased interest in the characterization of titanium as a catalyst for high-capacity hydrogen storage materials. A first-principles study (Yildirim and Ciraci 2005 Phys. Rev. Lett. 94 175501) demonstrated that a single Ti atom coated on a single-walled nanotube

  5. Expectancy of ergogenicity from sodium bicarbonate ingestion increases high-intensity cycling capacity

    National Research Council Canada - National Science Library

    Higgins, Matthew F; Shabir, Akbar

    2016-01-01

    ... ) influenced subsequent high-intensity cycling capacity. Eight recreationally active males (age, 21 ± 1 years; body mass, 75 ± 8 kg; height, 178 ± 4 cm; W PEAK = 205 ± 22 W) performed a graded incremental test to assess peak power output...

  6. Principals Fostering the Instructional Leadership Capacities of Department Chairs: A Strategy for Urban High School Reform

    Science.gov (United States)

    Klar, Hans W.

    2013-01-01

    A growing body of literature has highlighted the affordances of distributive forms of instructional leadership as a means to broaden and deepen instructional leadership capacity within schools. Yet, specifically how the capabilities of such key leaders as high school department chairs can be fostered to realize enhanced instructional capacity…

  7. 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.

  8. Thermodynamics of aqueous uranyl ion: Apparent and partial molar heat capacities and volumes of aqueous uranyl perchlorate from 10 to 55°C

    Science.gov (United States)

    Hovey, Jamey K.; Nguyen-Trung, Chinh; Tremaine, Peter R.

    1989-07-01

    Apparent molar heat capacities and volumes of aqueous solutions containing UO2(ClO4)2 in dilute (≈0.06 molal) HClO4 have been determined from 10 to 55°C. These results have been analyzed using Young's rule to obtain apparent molar volumes and heat capacities for the solute UO2(ClO42). The temperature dependences of the conventional standard-state heat capacity and volume functions for UO22+ (aq) are well represented by the following equations: V¯°/cm(30 mo1P-1) -80.94 + 0.6091 T - 0.001063T2 andC¯/p0/(J K-1 mol-1) = 350.5 - 0.8722T - 5308/T -90) that are valid from 10 to 55°C. These results differ substantially from results of earlier measurements employing different uranyl salts. These differences are likely due to the presence of ion-paired or hydrolyzed U (VI) species in the earlier studies.

  9. Thermophysical Properties of Cold- and Vacuum Plasma-Sprayed Cu-Cr-X Alloys, NiAl and NiCrAlY Coatings II: Specific Heat Capacity

    Science.gov (United States)

    Raj, S. V.

    2017-10-01

    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 (CS) 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, C P, of these coatings. The data were empirically regression-fitted with the equation: \\varvec{C}_{P} = AT^{4} + BT^{3} + CT^{2} + DT + \\varvec{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 C P using the Neumann-Kopp (NK) rule were in poor agreement with experimental data. Instead, a modification of the NK 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 C P > 3R, where R is the universal gas constant, were measured for all the alloys except NiAl for which C P < 3R at all temperatures.

  10. 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.

  11. Low temperature heat capacities and standard molar enthalpy of formation of sodium benzoate C{sub 6}H{sub 5}COONa (s)

    Energy Technology Data Exchange (ETDEWEB)

    Kong, Yu-Xia [College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, Shandong Province (China); Di, You-Ying, E-mail: yydi@lcu.edu.cn [College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, Shandong Province (China); Qi, Yu-Dong; Yang, Wei-Wei [College of Chemistry and Chemical Engineering, Liaocheng University, Liaocheng 252059, Shandong Province (China); Tan, Zhi-Cheng [Thermochemistry Laboratory, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023 (China)

    2009-05-05

    Sodium benzoate was synthesized by the method of liquid phase synthesis, in which benzoic acid and anhydrous sodium carbonate were chosen as the reactants. The structure and composition of the compound were characterized by FTIR, chemical analysis, elemental analysis and X-ray powder diffraction techniques. Low temperature heat capacities of the compound were measured by a precision automated adiabatic calorimeter over the temperature range from 78 to 400 K. A polynomial equation of the heat capacities as a function of the temperature was fitted by least square method. The smoothed heat capacities and the thermodynamic functions of the compound relative to 298.15 K have been calculated based on the equation. In accordance with Hess law, the standard molar enthalpy of formation of the title compound C{sub 6}H{sub 5}COONa (s) was determined to be {Delta}{sub f}H{sup o}{sub m}[C{sub 6}H{sub 5}COONa,s]=-(642.56{+-}0.64)kJmol{sup -1} by using an isoperibol solution-reaction calorimeter.

  12. Thermophysical Properties of Cold- and Vacuum Plasma-Sprayed Cu-Cr-X Alloys, NiAl and NiCrAlY Coatings II: Specific Heat Capacity

    Science.gov (United States)

    Raj, S. V.

    2017-11-01

    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 (CS) 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, C P, of these coatings. The data were empirically regression-fitted with the equation: \\varvec{C}_{P} = {AT}^{4} + {BT}^{3} + {CT}^{2} + DT + \\varvec{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 C P using the Neumann-Kopp (NK) rule were in poor agreement with experimental data. Instead, a modification of the NK 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 C P > 3 R, where R is the universal gas constant, were measured for all the alloys except NiAl for which C P < 3 R at all temperatures.

  13. Functional Capacity Assessed by the Map Task in Individuals at Clinical High-Risk for Psychosis.

    Science.gov (United States)

    McLaughlin, Danielle; Carrión, Ricardo E; Auther, Andrea M; Olvet, Doreen M; Addington, Jean; Bearden, Carrie E; Cadenhead, Kristin S; Cannon, Tyrone D; Heinssen, Robert K; Mathalon, Daniel H; McGlashan, Thomas H; Perkins, Diana O; Seidman, Larry J; Tsuang, Ming T; Walker, Elaine F; Woods, Scott W; Goldberg, Terry E; Harvey, Philip D; Cornblatt, Barbara A

    2016-09-01

    Recent studies have recognized that signs of functional disability in schizophrenia are evident in early phases of the disorder, and, as a result, can potentially serve as vulnerability markers of future illness. However, functional measures in the psychosis prodrome have focused exclusively on real-world achievements, rather than on the skills required to carry-out a particular real-world function (ie, capacity). Despite growing evidence that diminished capacity is critical to the etiology of the established disorder, virtually no attention has been directed towards assessing functional capacity in the pre-illness stages. In the present study, we introduce the Map task, a measure to assess functional capacity in adolescent and young-adult high-risk populations. The Map task was administered to 609 subjects at Clinical High-Risk (CHR) for psychosis and 242 Healthy Controls (HCs) participating in the North American Prodrome Longitudinal Study (NAPLS2). Subjects were required to efficiently complete a set of specified errands in a fictional town. CHR participants showed large impairments across major indices of the Map task, relative to the HCs. Most importantly, poor performance on the Map task significantly predicted conversion to psychosis, even after adjusting for age, IQ, clinical state, and other potential confounders. To the best of our knowledge, the Map task is one of the first laboratory-based measures to assess functional capacity in high-risk populations. Functional capacity deficits prior to the onset of psychosis may reflect a basic mechanism that underlies risk for psychosis. Early intervention targeting this domain may help to offset risk and independently improve long-term outcome. © The Author 2016. Published by Oxford University Press on behalf of the Maryland Psychiatric Research Center. All rights reserved. For permissions, please email: journals.permissions@oup.com.

  14. Plasma–Surface Interactions Under High Heat and Particle Fluxes

    Directory of Open Access Journals (Sweden)

    Gregory De Temmerman

    2013-01-01

    Full Text Available The plasma-surface interactions expected in the divertor of a future fusion reactor are characterized by extreme heat and particle fluxes interacting with the plasma-facing surfaces. Powerful linear plasma generators are used to reproduce the expected plasma conditions and allow plasma-surface interactions studies under those very harsh conditions. While the ion energies on the divertor surfaces of a fusion device are comparable to those used in various plasma-assited deposition and etching techniques, the ion (and energy fluxes are up to four orders of magnitude higher. This large upscale in particle flux maintains the surface under highly non-equilibrium conditions and bring new effects to light, some of which will be described in this paper.

  15. Performance of water source heat pump system using high-density polyethylene tube heat exchanger wound with square copper wire

    Directory of Open Access Journals (Sweden)

    Xin Wen Zhang

    2015-07-01

    Full Text Available Surface water source heat pump system is an energy-efficient heat pump system. Surface water heat exchanger is an important part of heat pump system that can affect the performance of the system. In order to enhance the performance of the system, the overall heat transfer coefficient (U value of the water exchanger using a 32A square copper coiled high-density polyethylene tube was researched. Comparative experiments were conducted between the performance of the coiled high-density polyethylene tube and the 32A smooth high-density polyethylene tube. At the same time, the coefficient of performance of the heat pump was investigated. According to the result, the U value of the coiled tube was 18% higher than that of the smooth tube in natural convection and 19% higher in forced convection. The coefficient of performance of the heat pump with the coiled tube is higher than that with the smooth tube. The economic evaluation of the coiled tube was also investigated.

  16. The Capacity of Finite-State Channels in the High-Noise Regime

    CERN Document Server

    Pfister, Henry D

    2010-01-01

    This paper considers the derivative of the entropy rate of a hidden Markov process with respect to the observation probabilities. The main result is a compact formula for the derivative that can be evaluated easily using Monte Carlo methods. It is applied to the problem of computing the capacity of a finite-state channel (FSC) and, in the high-noise regime, the formula has a simple closed-form expression that enables series expansion of the capacity of a FSC. This expansion is evaluated for a binary-symmetric channel under a (0,1) run-length limited constraint and an intersymbol-interference channel with Gaussian noise.

  17. Heat

    CERN Document Server

    Lawrence, Ellen

    2016-01-01

    Is it possible to make heat by rubbing your hands together? Why does an ice cube melt when you hold it? In this title, students will conduct experiments to help them understand what heat is. Kids will also investigate concepts such as which materials are good at conducting heat and which are the best insulators. Using everyday items that can easily be found around the house, students will transform into scientists as they carry out step-by-step experiments to answer interesting questions. Along the way, children will pick up important scientific skills. Heat includes seven experiments with detailed, age-appropriate instructions, surprising facts and background information, a "conclusions" section to pull all the concepts in the book together, and a glossary of science words. Colorful, dynamic designs and images truly put the FUN into FUN-damental Experiments.

  18. 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.

  19. A Major Constituent of Brown Algae for Use in High-Capacity Li-Ion Batteries

    Science.gov (United States)

    Kovalenko, Igor; Zdyrko, Bogdan; Magasinski, Alexandre; Hertzberg, Benjamin; Milicev, Zoran; Burtovyy, Ruslan; Luzinov, Igor; Yushin, Gleb

    2011-10-01

    The identification of similarities in the material requirements for applications of interest and those of living organisms provides opportunities to use renewable natural resources to develop better materials and design better devices. In our work, we harness this strategy to build high-capacity silicon (Si) nanopowder-based lithium (Li)-ion batteries with improved performance characteristics. Si offers more than one order of magnitude higher capacity than graphite, but it exhibits dramatic volume changes during electrochemical alloying and de-alloying with Li, which typically leads to rapid anode degradation. We show that mixing Si nanopowder with alginate, a natural polysaccharide extracted from brown algae, yields a stable battery anode possessing reversible capacity eight times higher than that of the state-of-the-art graphitic anodes.

  20. Metal-organic frameworks with high capacity and selectivity for harmful gases

    Science.gov (United States)

    Britt, David; Tranchemontagne, David; Yaghi, Omar M.

    2008-01-01

    Benchmarks have been established for the performance of six metal-organic frameworks (MOFs) and isoreticular MOFs (IRMOFs, which have the same underlying topology as MOF-5), MOF-5, IRMOF-3, MOF-74, MOF-177, MOF-199, and IRMOF-62, as selective adsorbents for eight harmful gases: sulfur dioxide, ammonia, chlorine, tetrahydrothiophene, benzene, dichloromethane, ethylene oxide, and carbon monoxide. Kinetic breakthrough measurements are used to determine the calculated dynamic adsorption capacity of each “benchmark” MOF for each gas. The capacity of each MOF is compared to that of a sample of Calgon BPL activated carbon. We find that pore functionality plays a dominant role in determining the dynamic adsorption performance of MOFs. MOFs featuring reactive functionality outperform BPL carbon in all but one case and exhibit high dynamic adsorption capacities up to 35% by weight. PMID:18711128

  1. Metal-organic frameworks with exceptionally high capacity for storage of carbon dioxide at room temperature.

    Science.gov (United States)

    Millward, Andrew R; Yaghi, Omar M

    2005-12-28

    Metal-organic frameworks (MOFs) show high CO2 storage capacity at room temperature. Gravimetric CO2 isotherms for MOF-2, MOF-505, Cu3(BTC)2, MOF-74, IRMOFs-11, -3, -6, and -1, and MOF-177 are reported up to 42 bar. Type I isotherms are found in all cases except for MOFs based on Zn4O(O2C)6 clusters, which reveal a sigmoidal isotherm (having a step). The various pressures of the isotherm steps correlate with increasing pore size, which indicates potential for gas separations. The amine functionality of the IRMOF-3 pore shows evidence of relatively increased affinity for CO2. Capacities qualitatively scale with surface area and range from 3.2 mmol/g for MOF-2 to 33.5 mmol/g (320 cm3(STP)/cm3, 147 wt %) for MOF-177, the highest CO2 capacity of any porous material reported.

  2. A Review of Boiling Heat Transfer Processes at High Heat Flux

    Science.gov (United States)

    1991-04-01

    Bjorge , et al. (Ref. 168) and Stephan and Auracher (Ref. 169) later presented variations of the superposition approach. For additional approaches... Bjorge , R. W., Hall, G. R., and Rohsenow, W. M., "Correlation of Forced Convection Boiling Heat Transfer Data," Int. J. Heat Mass Trans., Vol. 25, No

  3. High-Capacity Hybrid Optical Fiber-Wireless Communications Links in Access Networks

    DEFF Research Database (Denmark)

    Pang, Xiaodan

    and radio-over-fiber (RoF) systems employing wireless multi-input multi-output (MIMO) multiplexing technologies. Regarding high speed mm-wave links, this thesis focuses on high capacity fiber-wireless transmissions in both the V-band (50-75 GHz) and the Wband (75-110 GHz). Photonic mm-wave signal generation...... techniques with both coherent and incoherent optical sources are studied and demonstrated. Employments of advanced modulation formats including phase-shift keying (PSK), M-quadrature amplitude modulation (QAM) and orthogonal frequency-division multiplexing (OFDM) for high speed photonic-wireless transmission...... techniques. In conclusion, the results presented in the thesis show the feasibility of employing mm-wave signals, advanced modulation formats and spatial multiplexing technologies in next generation high capacity hybrid optical fiber-wireless access systems....

  4. Radiation and temperature effects on electronic components investigated under the CSTI high capacity power project

    Science.gov (United States)

    Schwarze, Gene E.; Niedra, Janis M.; Frasca, Albert J.; Wieserman, William R.

    1993-01-01

    The effects of nuclear radiation and high temperature environments must be fully known and understood for the electronic components and materials used in both the Power Conditioning and Control subsystem and the reactor Instrumentation and Control subsystem of future high capacity nuclear space power systems. This knowledge is required by the designer of these subsystems in order to develop highly reliable, long-life power systems for future NASA missions. A review and summary of the experimental results obtained for the electronic components and materials investigated under the power management element of the Civilian Space Technology Initiative (CSTI) high capacity power project are presented: (1) neutron, gamma ray, and temperature effects on power semiconductor switches, (2) temperature and frequency effects on soft magnetic materials; and (3) temperature effects on rare earth permanent magnets.

  5. Total lung capacity by plethysmography and high-resolution computed tomography in COPD.

    Science.gov (United States)

    Garfield, Jamie L; Marchetti, Nathaniel; Gaughan, John P; Steiner, Robert M; Criner, Gerard J

    2012-01-01

    To characterize and compare total lung capacity (TLC) measured by plethysmography with high-resolution computed tomography (HRCT), and to identify variables that predict the difference between the two modalities. Fifty-nine consecutive patients referred for the evaluation of COPD were retrospectively reviewed. Patients underwent full pulmonary function testing and HRCT within 3 months. TLC was obtained by plethysmography as per American Thoracic Society/European Respiratory Society standards and by HRCT using custom software on 0.75 and 5 mm thick contiguous slices performed at full inspiration (TLC). TLC measured by plethysmography correlated with TLC measured by inspiratory HRCT (r = 0.92, P volume in 1 second/forced vital capacity [FVC] and FVC%), static lung volumes (residual volume, percent predicted [RV%], total lung capacity, percent predicted [TLC%], functional residual capacity, percent predicted [FRC%], and inspiratory capacity, percent predicted), and percent emphysema. TLC by plethysmography and HRCT both demonstrated significant inverse correlations with diffusion impairment. The absolute difference between TLC measured by plethysmography and HRCT increased as RV%, TLC%, and FRC% increased. Gas trapping (RV% and FRC%) independently predicted the difference in TLC between plethysmography and HRCT. In COPD, TLC by plethysmography can be up to 2 L greater than inspiratory HRCT. Gas trapping independently predicts patients for whom TLC by plethysmography differs significantly from HRCT.

  6. High-Capacity and Photoregenerable Composite Material for Efficient Adsorption and Degradation of Phenanthrene in Water.

    Science.gov (United States)

    Liu, Wen; Cai, Zhengqing; Zhao, Xiao; Wang, Ting; Li, Fan; Zhao, Dongye

    2016-10-18

    We report a novel composite material, referred to as activated charcoal supported titanate nanotubes (TNTs@AC), for highly efficient adsorption and photodegradation of a representative polycyclic aromatic hydrocarbon (PAH), phenanthrene. TNTs@AC was prepared through a one-step hydrothermal method, and is composed of an activated charcoal core and a shell of carbon-coated titanate nanotubes. TNTs@AC offered a maximum Langmuir adsorption capacity of 12.1 mg/g for phenanthrene (a model PAH), which is ∼11 times higher than the parent activated charcoal. Phenanthrene was rapidly concentrated onto TNTs@AC, and subsequently completely photodegraded under UV light within 2 h. The photoregenerated TNTs@AC can then be reused for another adsorption-photodegradation cycle without significant capacity or activity loss. TNTs@AC performed well over a wide range of pH, ionic strength, and dissolved organic matter. Mechanistically, the enhanced adsorption capacity is attributed to the formation of carbon-coated ink-bottle pores of the titanate nanotubes, which are conducive to capillary condensation; in addition, the modified microcarbon facilitates transfer of excited electrons, thereby inhibiting recombination of the electron-hole pairs, resulting in high photocatalytic activity. The combined high adsorption capacity, photocatalytic activity, and regenerability/reusability merit TNTs@AC a very attractive material for concentrating and degrading a host of micropollutants in the environment.

  7. Curtailment in a Highly Renewable Power System and Its Effect on Capacity Factors

    Directory of Open Access Journals (Sweden)

    Alexander Kies

    2016-06-01

    Full Text Available The capacity factor of a power plant is the ratio of generation over its potential generation. It is an important measure to describe wind and solar resources. However, the fluctuating nature of renewable power generation makes it difficult to integrate all generation at times. Whenever generation exceeds the load, curtailment or storage of energy is required. With increasing renewable shares in the power system, the level of curtailment will further increase. In this work, the influence of the curtailment on the capacity factors for a highly renewable German power system is studied. An effective capacity factor is introduced, and the implications for the distribution of renewable power plants are discussed. Three years of highly-resolved weather data were used to model wind and solar power generation. Together with historical load data and a transmission model, a possible future German power system was simulated. It is shown that effective capacity factors for unlimited transmission are strongly reduced by up to 60% (wind and 70% (photovoltaics and therefore of limited value in a highly renewable power system. Furthermore, the results demonstrate that wind power benefits more strongly from a reinforced transmission grid than photovoltaics (PV does.

  8. Experimental investigations of an AC pulse heating method for vehicular high power lithium-ion batteries at subzero temperatures

    Science.gov (United States)

    Zhu, Jiangong; Sun, Zechang; Wei, Xuezhe; Dai, Haifeng; Gu, Weijun

    2017-11-01

    Effect of the AC (alternating current) pulse heating method on battery SoH (state of health) for large laminated power lithium-ion batteries at low temperature is investigated experimentally. Firstly, excitation current frequencies, amplitudes, and voltage limitations on cell temperature evolution are studied. High current amplitudes facilitate the heat accumulation and temperature rise. Low frequency region serves as a good innovation to heat the battery because of the large impedance. Wide voltage limitations also enjoy better temperature evolution owing to the less current modulation, but the temperature difference originated from various voltage limitations attenuates due to the decrement of impedance resulting from the temperature rise. Experiments with the thermocouple-embedded cell manifest good temperature homogeneity between the battery surface and interior during the AC heating process. Secondly, the cell capacity, Direct Current resistance and Electrochemical Impedance Spectroscopy are all calibrated to assess the battery SoH after the hundreds of AC pulse heating cycles. Also, all cells are disassembled to investigate the battery internal morphology with the employment of Scanning Electron Microscope and Energy-Dispersive x-ray Spectroscopy techniques. The results indicate that the AC heating method does not aggravate the cell degradation even in the low frequency range (0.5 Hz) under the normal voltage protection limitation.

  9. An Implementation fo a Flexible Topology Management System for Aerial High Capacity Directional Networks

    Science.gov (United States)

    2015-10-01

    different transmit and receive frequency bands from the local wide-area coverage links. The primary performance metric for candidate topology ...An Implementation of a Flexible Topology Management System for Aerial High Capacity Directional Networks Joy Wang, Patricia Deutsch, Andrea Coyle...several advantages such as high data rates at long ranges and interference resistant links when paired with directional systems. On the flip side, topology

  10. Experimental results for hydrocarbon refrigerant vaporization inside brazed plate heat exchangers at high pressure

    DEFF Research Database (Denmark)

    Desideri, Adriano; Ommen, Torben Schmidt; Wronski, Jorrit

    2016-01-01

    In recent years the interest in small capacity organic Rankine cycle (ORC) power systems for harvesting low qualitywaste thermal energy from industrial processes has been steadily growing. Micro ORC systems are normally equippedwith 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 modelbased control strategies. The current literature is lacking experimental data and validated correlations for vaporization of organic...... fluids at typical working conditions of ORC systems for low temperature waste heat recovery (WHR) applications. Based on these premises, a novel testrig has been recently designed and built at the Technical University of Denmark to simulate the evaporating condition occurring in a small capacity ORC...

  11. In Situ Chemical Synthesis of Lithium Fluoride/Metal Nanocomposite for High Capacity Prelithiation of Cathodes.

    Science.gov (United States)

    Sun, Yongming; Lee, Hyun-Wook; Zheng, Guangyuan; Seh, Zhi Wei; Sun, Jie; Li, Yanbin; Cui, Yi

    2016-02-10

    The initial lithium loss during the formation stage is a critical issue that significantly reduces the specific capacity and energy density of current rechargeable lithium-ion batteries (LIBs). An effective strategy to solve this problem is using electrode prelithiation additives that can work as a secondary lithium source and compensate the initial lithium loss. Herein we show that nanocomposites of lithium fluoride and metal (e.g., LiF/Co and LiF/Fe) can be efficient cathode prelithiation materials. The thorough mixing of ultrafine lithium fluoride and metal particles (∼5 nm) allows lithium to be easily extracted from the nanocomposites via an inverse conversion reaction. The LiF/Co nanocomposite exhibits an open circuit voltage (OCV, 1.5 V) with good compatibility with that of existing cathode materials and delivers a high first-cycle "donor" lithium-ion capacity (516 mA h g(-1)). When used as an additive to a LiFePO4 cathode, the LiF/Co nanocomposite provides high lithium compensation efficiency. Importantly, the as-formed LiF/metal nanocomposites possess high stability and good compatibility with the regular solvent, binder, and existing battery processing conditions, in contrast with the anode prelithiation materials that usually suffer from issues of high chemical reactivity and instability. The facile synthesis route, high stability in ambient and battery processing conditions, and high "donor" lithium-ion capacity make the LiF/metal nanocomposites ideal cathode prelithiation materials for LIBs.

  12. Mathematical Simulation of Heat Transfer in Heterogenous Forest Fuel Layer Influenced by Heated Up to High Temperatures Steel Particle

    Directory of Open Access Journals (Sweden)

    Baranovskiy Nikolay V.

    2014-01-01

    Full Text Available Heterogeneity of forest fuel layer renders the important influence on forest fire occurrence processes. One of sources of the raised temperature on forested territories is metal particles heated up to high temperatures. Such particles can be formed as a result of welding of metals on forested territories. The present paper represents the heat transfer research in forest fuel at the influence of metal particle heated up to high temperatures. The heterogonous forest fuel layer with inclusions of small wooden branches and chips is considered. Such object research is urgent especially at fire forecasting on forest cutting. The technology of mathematical simulation is used. The two-dimensional problem of heat transfer in forest fuel layer structure with wood inclusions is solved.

  13. High Areal Capacity and Lithium Utilization in Anodes Made of Covalently Connected Graphite Microtubes.

    Science.gov (United States)

    Jin, Song; Sun, Zhaowei; Guo, Yali; Qi, Zhikai; Guo, Chengkun; Kong, Xianghua; Zhu, Yanwu; Ji, Hengxing

    2017-10-01

    Lithium metal is an attractive anode material for rechargeable batteries because of its high theoretical specific capacity of 3860 mA h g(-1) and the lowest negative electrochemical potential of -3.040 V versus standard hydrogen electrode. Despite extensive research efforts on tackling the safety concern raised by Li dendrites, inhibited Li dendrite growth is accompanied with decreased areal capacity and Li utilization, which are still lower than expectation for practical use. A scaffold made of covalently connected graphite microtubes is reported, which provides a firm and conductive framework with moderate specific surface area to accommodate Li metal for anodes of Li batteries. The anode presents an areal capacity of 10 mA h cm(-2) (practical gravimetric capacity of 913 mA h g(-1) ) at a current density of 10 mA cm(-2) , with Li utilization of 91%, Coulombic efficiencies of ≈97%, and long lifespan of up to 3000 h. The analysis of structure evolution during charge/discharge shows inhibited lithium dendrite growth and a reversible electrode volume change of ≈9%. It is suggested that an optimized microstructure with moderate electrode/electrolyte interface area is critical to accommodate volume change and inhibit the risks of irreversible Li consumption by side reactions and Li dendrite growth for high-performance Li-metal anodes. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  14. High-capacity method for hiding data in the discrete cosine transform domain

    Science.gov (United States)

    Qazanfari, Kazem; Safabakhsh, Reza

    2013-10-01

    Steganography is the art and science of hiding data in different media such as texts, audios, images, and videos. Data hiding techniques are generally divided into two groups: spatial and frequency domain techniques. Spatial domain methods generally have low security and, as a result, are less attractive to researchers. Discrete cosine transform (DCT) is the most common transform domain used in steganography and JPEG compression. Since a large number of the DCT coefficients of JPEG images are zero, the capacity of DCT domain-based steganography methods is not very high. We present a high-capacity method for hiding messages in the DCT domain. We describe the method in two classes where the receiver has and where the receiver does not have the cover image. In each class, we consider three cases for each coefficient. By considering n coefficients, there are 3n different situations. The method embeds ⌊log2 3n⌋ bits in these n coefficients. We show that the maximum reachable capacity by our method is 58% higher than the other general steganography methods. Experimental results show that the histogram-based steganalysis methods cannot detect the stego images produced by the proposed method while the capacity is increased significantly.

  15. Extreme genetic structure in a social bird species despite high dispersal capacity.

    Science.gov (United States)

    Morinha, Francisco; Dávila, José A; Bastos, Estela; Cabral, João A; Frías, Óscar; González, José L; Travassos, Paulo; Carvalho, Diogo; Milá, Borja; Blanco, Guillermo

    2017-05-01

    Social barriers have been shown to reduce gene flow and contribute to genetic structure among populations in species with high cognitive capacity and complex societies, such as cetaceans, apes and humans. In birds, high dispersal capacity is thought to prevent population divergence unless major geographical or habitat barriers induce isolation patterns by dispersal, colonization or adaptation limitation. We report that Iberian populations of the red-billed chough, a social, gregarious corvid with high dispersal capacity, show a striking degree of genetic structure composed of at least 15 distinct genetic units. Monitoring of marked individuals over 30 years revealed that long-distance movements over hundreds of kilometres are common, yet recruitment into breeding populations is infrequent and highly philopatric. Genetic differentiation is weakly related to geographical distance, and habitat types used are overall qualitatively similar among regions and regularly shared by individuals of different populations, so that genetic structure is unlikely to be due solely to isolation by distance or isolation by adaptation. Moreover, most population nuclei showed relatively high levels of genetic diversity, suggesting a limited role for genetic drift in significantly differentiating populations. We propose that social mechanisms may underlie this unprecedented level of genetic structure in birds through a pattern of isolation by social barriers not yet described, which may have driven this remarkable population divergence in the absence of geographical and environmental barriers. © 2017 John Wiley & Sons Ltd.

  16. High-Capacity and Rapid Removal of Refractory NOM Using Nanoscale Anion Exchange Resin.

    Science.gov (United States)

    Johnson, Billy R; Eldred, Tim B; Nguyen, Andy T; Payne, William M; Schmidt, Emily E; Alansari, Amir Y; Amburgey, James E; Poler, Jordan C

    2016-07-20

    As human health concerns over disinfection byproducts (DBP) in drinking water increase, so does the need to develop new materials that remove them rapidly and at high capacity. Ion exchange (IEX) is an effective method for the removal of natural organic matter (NOM), especially anion exchange resins (AERs) with quaternary ammonium functional groups. However, capacity is limited in existing commercial resin materials because adsorbates can only interact with the outermost surface area, which makes these products inefficient on a mass basis. We have synthesized a novel "NanoResin" exploiting the enhanced NOM removal of the quaternary ammonium resin while utilizing the vast surface area of SWCNTs, which act as scaffolding for the resin. Our nanomaterials show increased adsorption capacity compared to commercially available adsorbents, in a fraction of the time. This NanoResin requires only about 10 s to reach ion-exchange equilibrium. Comparatively, commercial AERs only achieved partial removal after more than 30 min. High capacity adsorption of a low molecular weight (MW) surrogate has been measured. NOM removal was demonstrated in solutions of both low and high specific UV absorbance (SUVA) composition with these nanomaterials. Additionally, the NanoResin showed enhanced removal of a NOM concentrate sample taken from Myrtle Beach, SC, demonstrating NanoResin is an effective method of removal for refractory NOM in a natural aqueous environment. Synthesis and characterization of the polymers and nanomaterials are presented below. Adsorption capacity, adsorption kinetics, and the regeneration and reusability of these new materials for NOM removal are described. The open matrix microstructure precludes any intraparticle diffusion of adsorbates; thus, these nanomaterials act as a "contact resin".

  17. Systematic Studies on Anharmonicity of Rattling Phonons in Type I Clathrates by Low Temperature Heat Capacity Measurements

    Science.gov (United States)

    Tanigaki, Katsumi; Wu, Jiazhen; Tanabe, Yoichi; Heguri, Satoshi; Shiimotani, Hidekazu; Tohoku University Collaboration

    2014-03-01

    Clathrates are featured by cage-like polyhedral hosts mainly composed of the IVth group elements of Si, Ge, or Sn and alkali metal or alkaline-earth metal elements can be accommodated inside as a guest atom. One of the most intriguing issues in clathrates is their outstanding high thermoelectric performances thanks to the low thermal conductivity. Being irrespective of good electric conductivity σ, the guest atom motions provide a low-energy lying less-dispersive phonons and can greatly suppress thermal conductivity κ. This makes clathrates close to the concept of ``phonon glass electron crystal: PGEC'' and useful in thermoelectric materials from the viewpoint of the figure of merit. In the present study, we show that the local phonon anharmonicity indicated by the tunneling-term of the endohedral atoms (αT) and the itinerant-electron term (γeT), both of which show T-linear dependences in specific heat Cp, can successfully be separated by employing single crystals with various carrier concentrations in a wide range of temperture experimennts. The factors affecting on the phonon anharmonicity as well as the strength of electron-phonon interactions will be discussed based on our recent experiments. The research was financially supported by Ministry of Education, Science, Sports and Culture, Grant in Aid for Science, and Technology of Japan.

  18. Capillary zone electrophoresis-mass spectrometry with microliter-scale loading capacity, 140 min separation window and high peak capacity for bottom-up proteomics.

    Science.gov (United States)

    Chen, Daoyang; Shen, Xiaojing; Sun, Liangliang

    2017-06-21

    Better peptide separation is required for bottom-up proteomics for further improving the proteome coverage. The two-dimensional liquid chromatography (2D-LC) systems only explore differences among peptides in their hydrophobicity (reversed-phase, RP) and charge (strong cation/anion exchange, SCX/SAX). Alternative separation techniques with different separation mechanisms are required to further improve the separation. Capillary zone electrophoresis (CZE) is an attractive alternative because it has high efficiency for separation of biomolecules and it separates analytes based on their size-to-charge ratios, complementary with LC. However, the low loading capacity and narrow separation window of CZE limit its wide application for large-scale proteomics. In this manuscript, we present an automated CZE-mass spectrometry (MS) system for solving those issues. The CZE-MS system can approach at least half-a-microliter loading capacity with good robustness and reproducibility, can routinely use over 12% of the available sample in the sample vial for analysis, and can generate a 140 min separation window and high peak capacity (∼380) for complex proteome analysis. The results represent the highest peak capacity and the widest separation window of CZE for peptide separation with a microliter-scale loading capacity. It is the first time that CZE-MS approaches both the microliter-scale loading capacity and over 2-hour separation window for analysis of complex samples. The automated CZE-MS system dramatically reduces the gap between CZE-MS and RPLC-MS in terms of loading capacity, separation window and peak capacity. It truly opens the door for large-scale bottom-up proteomics using CZE-MS.

  19. Growth of a dry spot under a vapor bubble at high heat flux and high pressure

    CERN Document Server

    Nikolayev, Vadim; Lagier, G -L; Hegseth, J

    2016-01-01

    We report a 2D modeling of the thermal diffusion-controlled growth of a vapor bubble attached to a heating surface during saturated boiling. The heat conduction problem is solved in a liquid that surrounds a bubble with a free boundary and in a semi-infinite solid heater by the boundary element method. At high system pressure the bubble is assumed to grow slowly, its shape being defined by the surface tension and the vapor recoil force, a force coming from the liquid evaporating into the bubble. It is shown that at some typical time the dry spot under the bubble begins to grow rapidly under the action of the vapor recoil. Such a bubble can eventually spread into a vapor film that can separate the liquid from the heater thus triggering the boiling crisis (critical heat flux).

  20. Hybrid Heat Pipes for High Heat Flux Spacecraft Thermal Control Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Grooved aluminum/ammonia Constant Conductance Heat Pipes (CCHPs) are the standard for thermal control in zero-gravity. Unfortunately, they are limited in terms of...