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Sample records for complex vapor heated

  1. Passive Vaporizing Heat Sink

    NASA Technical Reports Server (NTRS)

    Knowles, TImothy R.; Ashford, Victor A.; Carpenter, Michael G.; Bier, Thomas M.

    2011-01-01

    A passive vaporizing heat sink has been developed as a relatively lightweight, compact alternative to related prior heat sinks based, variously, on evaporation of sprayed liquids or on sublimation of solids. This heat sink is designed for short-term dissipation of a large amount of heat and was originally intended for use in regulating the temperature of spacecraft equipment during launch or re-entry. It could also be useful in a terrestrial setting in which there is a requirement for a lightweight, compact means of short-term cooling. This heat sink includes a hermetic package closed with a pressure-relief valve and containing an expendable and rechargeable coolant liquid (e.g., water) and a conductive carbon-fiber wick. The vapor of the liquid escapes when the temperature exceeds the boiling point corresponding to the vapor pressure determined by the setting of the pressure-relief valve. The great advantage of this heat sink over a melting-paraffin or similar phase-change heat sink of equal capacity is that by virtue of the =10x greater latent heat of vaporization, a coolant-liquid volume equal to =1/10 of the paraffin volume can suffice.

  2. Vapor compression heat pump system field tests at the TECH complex

    NASA Astrophysics Data System (ADS)

    Baxter, V. D.

    1985-07-01

    The Tennessee Energy Conservation In Housing (TECH) complex has been utilized since 1977 as a field test site for several novel and conventional heat pump systems for space conditioning and water heating. Systems tested include the Annual Cycle Energy System (ACES), solar assisted heat pumps (SAHP) both parallel and series, two conventional air-to-air heat pumps, an air-to-air heat pump with desuperheater water heater, and horizontal coil and multiple shallow vertical coil ground-coupled heat pumps (GCHP). A direct comparison of the measured annual performance of the test systems was not possible. However, a cursory examination revealed that the ACES had the best performance. However, its high cost makes it unlikely that it will achieve widespread use. Costs for the SAHP systems are similar to those of the ACES but their performance is not as good. Integration of water heating and space conditioning functions with a desuperheater yielded significant efficiency improvement at modest cost. The GCHP systems performed much better for heating than for cooling and may well be the most efficient alternative for residences in cold climates.

  3. Understanding Latent Heat of Vaporization.

    ERIC Educational Resources Information Center

    Linz, Ed

    1995-01-01

    Presents a simple exercise for students to do in the kitchen at home to determine the latent heat of vaporization of water using typical household materials. Designed to stress understanding by sacrificing precision for simplicity. (JRH)

  4. Understanding Latent Heat of Vaporization.

    ERIC Educational Resources Information Center

    Linz, Ed

    1995-01-01

    Presents a simple exercise for students to do in the kitchen at home to determine the latent heat of vaporization of water using typical household materials. Designed to stress understanding by sacrificing precision for simplicity. (JRH)

  5. Vapor phase heat transport systems

    NASA Astrophysics Data System (ADS)

    Hedstrom, J. C.; Neeper, D. A.

    1985-09-01

    Progress in theoretical and experimental investigations of various forms of a vapor transport system for solar space heating is described, which could also be applied to service water heating. The refrigerant is evaporated in a solar collector, which may be located on the external wall or roof of a building. The vapor is condensed in a passively discharged thermal storage unit located within the building. The condensed liquid can be returned to the collector either by a motor-driven pump or by a completely passive self-pumping mechanism in which the vapor pressure lifts the liquid from the condenser to the collector. The theoretical investigation analyzes this self-pumping scheme. Experiments in solar test cells compared the operation of both passive and active forms of the vapor system with the operation of a passive water wall. The vapor system operates as expected, with potential advantages over other passive systems in design flexibility and energy yield.

  6. Vapor-Resistant Heat-Pipe Artery

    NASA Technical Reports Server (NTRS)

    Dussinger, Peter M.; Shaubach, Robert M.; Buchko, Matt

    1991-01-01

    Vapor lock in heat pipe delayed or prevented. Modifications of wick prevent flow of vapor into, or formation of vapor in, liquid-return artery. Small pores of fine-grained sintered wick help to prevent formation of large bubbles. Slotted tube offers few nucleation sites for bubbles. Improves return of liquid in heat pipe.

  7. VAPOR PRESSURES AND HEATS OF VAPORIZATION OF PRIMARY COAL TARS

    SciTech Connect

    Eric M. Suuberg; Vahur Oja

    1997-07-01

    This project had as its main focus the determination of vapor pressures of coal pyrolysis tars. It involved performing measurements of these vapor pressures and from them, developing vapor pressure correlations suitable for use in advanced pyrolysis models (those models which explicitly account for mass transport limitations). This report is divided into five main chapters. Each chapter is a relatively stand-alone section. Chapter A reviews the general nature of coal tars and gives a summary of existing vapor pressure correlations for coal tars and model compounds. Chapter B summarizes the main experimental approaches for coal tar preparation and characterization which have been used throughout the project. Chapter C is concerned with the selection of the model compounds for coal pyrolysis tars and reviews the data available to us on the vapor pressures of high boiling point aromatic compounds. This chapter also deals with the question of identifying factors that govern the vapor pressures of coal tar model materials and their mixtures. Chapter D covers the vapor pressures and heats of vaporization of primary cellulose tars. Chapter E discusses the results of the main focus of this study. In summary, this work provides improved understanding of the volatility of coal and cellulose pyrolysis tars. It has resulted in new experimentally verified vapor pressure correlations for use in pyrolysis models. Further research on this topic should aim at developing general vapor pressure correlations for all coal tars, based on their molecular weight together with certain specific chemical characteristics i.e. hydroxyl group content.

  8. Fabrication and evaluation of chemically vapor deposited tungsten heat pipe

    NASA Technical Reports Server (NTRS)

    Bacigalupi, R. J.

    1972-01-01

    A network of lithium-filled tungsten heat pipes is considered as a method of heat extraction from high temperature nuclear reactors. The need for material purity and shape versatility in these applications dictates the use of chemically vapor deposited (CVD) tungsten. Adaptability of CVD tungsten to complex heat pipe designs is shown. Deposition and welding techniques are described. Operation of two lithium-filled CVD tungsten heat pipes above 1800 K is discussed.

  9. Multilead, Vaporization-Cooled Soldering Heat Sink

    NASA Technical Reports Server (NTRS)

    Rice, John

    1995-01-01

    Vaporization-cooled heat sink proposed for use during soldering of multiple electrical leads of packaged electronic devices to circuit boards. Heat sink includes compliant wicks held in grooves on edges of metal fixture. Wicks saturated with water. Prevents excessive increases in temperature at entrances of leads into package.

  10. Open-cycle vapor compression heat pump

    NASA Astrophysics Data System (ADS)

    Sakhuja, R.; Becker, F. E.

    1981-05-01

    Recovery and upgrading of low-grade steam or waste heat sources offers a great potential of energy conservation. Thermo Electron is developing an open cycle vapor compression steam heat pump to meet this objective. The system utilizes excess low-pressure steam or that produced from an industrial excess heat source with a waste heat boiler and compresses this steam to the desired pressure level for process use. The compressor is driven by a prime mover such as a gas turbine, gas engine, etc. The prime mover exhaust heat also can be recovered to generate additional process steam. The fuel consumption of this system can be as low as 30 to 50 percent in comparison to a direct-fired boiler over the expected range of process conditions. Simple payback periods as low as one year can be achieved.

  11. Passive vapor transport solar heating systems

    SciTech Connect

    Hedstrom, J.C.; Neeper, D.A.

    1985-01-01

    In the systems under consideration, refrigerant is evaporated in a solar collector and condensed in thermal storage for space or water heating located within the building at a level below that of the collector. Condensed liquid is lifted to an accumulator above the collector by the vapor pressure generated in the collector. Tests of two systems are described, and it is concluded that one of these systems offers distinct advantages.

  12. Vapor-phase heat-transport system

    NASA Astrophysics Data System (ADS)

    Hedstrom, J. C.

    1983-11-01

    A vapor-phase heat-transport system is being tested in one of the passive test cells at Los Alamos. The system consists of one selective-surface collector and a condenser inside a water storage tank. The refrigerant, R-11, can be returned to the collector by gravity or with a pump. Results from several operating configurations are presented, together with a comparison with other passive systems. A new self-pumping concept is presented.

  13. Vapor-phase heat-transport system

    NASA Astrophysics Data System (ADS)

    Hedstrom, J. C.

    A vapor-phase heat-transport system is being tested in one of the passive test cells at Los Alamos. The system consists of one selective-surface collector and a condenser inside a water storage tank. The refrigerant, R-11, can be returned to the collector by gravity or with a pump. Results from several operating configurations are presented, together with a comparison with other passive systems. A new self-pumping concept is presented.

  14. Advanced chemical heat pumps using liquid-vapor reactions

    NASA Astrophysics Data System (ADS)

    Kirol, L.

    Chemical heat pumps utilizing liquid-vapor reactions can be configured in forms analogous to electric drive vapor-compression heat pumps and heat activated absorption heat pumps. Basic thermodynamic considerations eliminate some heat pumps and place restrictive working fluid requirements on others, but two thermodynamically feasible systems have significant potential advantage over conventional technology. An electric drive reactive heat pump can use smaller heat exchangers and compressor than a vapor-compression machine, and have more flexible operating characteristics. A waste heat driven heat pump (temperature amplifier) using liquid-vapor chemical reactions can operate with higher coefficient of performance and smaller heat exchangers than an absorption temperature amplifying heat pump. Higher temperatures and larger temperature lifts should also be possible.

  15. Analysis of the transient compressible vapor flow in heat pipes

    NASA Technical Reports Server (NTRS)

    Jang, J. H.; Faghri, A.; Chang, W. S.

    1989-01-01

    The transient compressible one-dimensional vapor flow dynamics in a heat pipe is modeled. The numerical results are obtained by using the implicit non-iterative Beam-Warming finite difference method. The model is tested for simulated heat pipe vapor flow and actual vapor flow in cylindrical heat pipes. A good comparison of the present transient results for the simulated heat pipe vapor flow with the previous results of a two-dimensional numerical model is achieved and the steady state results are in agreement with the existing experimental data. The transient behavior of the vapor flow under subsonic, sonic, and supersonic speeds and high mass flow rates are successfully predicted. The one-dimensional model also describes the vapor flow dynamics in cylindrical heat pipes at high temperatures.

  16. Vapor-modulated heat pipe for improved temperature control

    NASA Technical Reports Server (NTRS)

    Edwards, D. K.; Eninger, J. E.; Ludeke, E. E.

    1978-01-01

    Dryout induced by vapor throttling makes control of equipment temperature less dependent on variations in sink environment. Mechanism controls flow of vapor in heat pipe by using valve in return path to build difference in pressure and also difference in saturation temperature of the vapor. In steady state, valve closes just enough to produce partial dryout that achieves required temperature drop.

  17. Vapor-modulated heat pipe for improved temperature control

    NASA Technical Reports Server (NTRS)

    Edwards, D. K.; Eninger, J. E.; Ludeke, E. E.

    1978-01-01

    Dryout induced by vapor throttling makes control of equipment temperature less dependent on variations in sink environment. Mechanism controls flow of vapor in heat pipe by using valve in return path to build difference in pressure and also difference in saturation temperature of the vapor. In steady state, valve closes just enough to produce partial dryout that achieves required temperature drop.

  18. Analysis of the transient compressible vapor flow in heat pipe

    NASA Technical Reports Server (NTRS)

    Jang, Jong Hoon; Faghri, Amir; Chang, Won Soon

    1989-01-01

    The transient compressible one-dimensional vapor flow dynamics in a heat pipe is modeled. The numerical results are obtained by using the implicit non-iterative Beam-Warming finite difference method. The model is tested for simulated heat pipe vapor flow and actual flow in cylindrical heat pipes. A good comparison of the present transient results for the simulated heat pipe vapor flow with the previous results of a two-dimensional numerical model is achieved and the steady state results are in agreement with the existing experimental data. The transient behavior of the vapor flow under subsonic, sonic, and supersonic speeds and high mass flow rates are successfully predicted. The one-dimensional model also describes the vapor flow dynamics in cylindrical heat pipes at high temperatures.

  19. A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium

    NASA Astrophysics Data System (ADS)

    McCarron, Daniel J.; Hughes, Ifan G.; Tierney, Patrick; Cornish, Simon L.

    2007-09-01

    The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D2 transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude.

  20. A heated vapor cell unit for dichroic atomic vapor laser lock in atomic rubidium.

    PubMed

    McCarron, Daniel J; Hughes, Ifan G; Tierney, Patrick; Cornish, Simon L

    2007-09-01

    The design and performance of a compact heated vapor cell unit for realizing a dichroic atomic vapor laser lock (DAVLL) for the D(2) transitions in atomic rubidium is described. A 5 cm long vapor cell is placed in a double-solenoid arrangement to produce the required magnetic field; the heat from the solenoid is used to increase the vapor pressure and correspondingly the DAVLL signal. We have characterized experimentally the dependence of important features of the DAVLL signal on magnetic field and cell temperature. For the weaker transitions both the amplitude and gradient of the signal are increased by an order of magnitude.

  1. Potassium Rankine cycle vapor chamber (heat pipe) radiator study

    NASA Technical Reports Server (NTRS)

    Gerrels, E. E.; Killen, R. E.

    1971-01-01

    A structurally integrated vapor chamber fin (heat pipe) radiator is defined and evaluated as a potential candidate for rejecting waste heat from the potassium Rankine cycle powerplant. Several vapor chamber fin geometries, using stainless steel construction, are evaluated and an optimum is selected. A comparison is made with an operationally equivalent conduction fin radiator. Both radiators employ NaK-78 in the primary coolant loop. In addition, the Vapor Chamber Fin (VCF) radiator utilizes sodium in the vapor chambers. Preliminary designs are developed for the conduction fin and VCF concepts. Performance tests on a single vapor chamber were conducted to verify the VCF design. A comparison shows the conduction fin radiator easier to fabricate, but heavier in weight, particularly as meteoroid protection requirements become more stringent. While the analysis was performed assuming the potassium Rankine cycle powerplant, the results are equally applicable to any system radiating heat to space in the 900 to 1400 F temperature range.

  2. Heat-Exchange Fluids for Sulfuric Acid Vaporizers

    NASA Technical Reports Server (NTRS)

    Lawson, D. D.; Petersen, G. R.

    1982-01-01

    Some fluorine-substituted organic materials meet criteria for heat-exchange fluids in contact with sulfuric acid. Most promising of these are perfluoropropylene oxide polymers with degree of polymerization (DP) between 10 and 50. It is desirable to have DP in high range because vapor pressure of material decreases as DP increases, and high-DP liquids have lower loss due to vaporization.

  3. Feasibility of a complex compound heat pump

    NASA Astrophysics Data System (ADS)

    Rockenfeller, Uwe

    1987-07-01

    A feasibility study is described of a double effect gas fired heat pump using ammoniated solid vapor complex compounds as the working media. The cycle takes advantage of the coordinative characteristics of complex compound ligand bonds resulting in large coordination spheres with only one degree of freedom. The cycle has high efficiency, no moving parts, and minimum electrical parasitic requirements. Fluid properties of candidate materials were measured with respect to vapor pressure equilibria, coordination properties and thermal stability. Preliminary reaction rate measurements were performed in adsorption and desorption processes. A computer model of double effect cycle was developed in order to predict the operating performance of the candidate complex compound media. The computer model was used to determine preliminary heat balances and coefficients of performance.

  4. Heat Pipe Vapor Dynamics. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Issacci, Farrokh

    1990-01-01

    The dynamic behavior of the vapor flow in heat pipes is investigated at startup and during operational transients. The vapor is modeled as two-dimensional, compressible viscous flow in an enclosure with inflow and outflow boundary conditions. For steady-state and operating transients, the SIMPLER method is used. In this method a control volume approach is employed on a staggered grid which makes the scheme very stable. It is shown that for relatively low input heat fluxes the compressibility of the vapor flow is low and the SIMPLER scheme is suitable for the study of transient vapor dynamics. When the input heat flux is high or the process under a startup operation starts at very low pressures and temperatures, the vapor is highly compressible and a shock wave is created in the evaporator. It is shown that for a wide range of input heat fluxes, the standard methods, including the SIMPLER scheme, are not suitable. A nonlinear filtering technique, along with the centered difference scheme, are then used for shock capturing as well as for the solution of the cell Reynolds-number problem. For high heat flux, the startup transient phase involves multiple shock reflections in the evaporator region. Each shock reflection causes a significant increase in the local pressure and a large pressure drop along the heat pipe. Furthermore, shock reflections cause flow reversal in the evaporation region and flow circulations in the adiabatic region. The maximum and maximum-averaged pressure drops in different sections of the heat pipe oscillate periodically with time because of multiple shock reflections. The pressure drop converges to a constant value at steady state. However, it is significantly higher than its steady-state value at the initiation of the startup transient. The time for the vapor core to reach steady-state condition depends on the input heat flux, the heat pipe geometry, the working fluid, and the condenser conditions. However, the vapor transient time, for an Na

  5. Forced convection heat transfer to air/water vapor mixtures

    NASA Technical Reports Server (NTRS)

    Richards, D. R.; Florschuetz, L. W.

    1984-01-01

    Heat transfer coefficients were measured using both dry and humid air in the same forced convection cooling scheme and were compared using appropriate nondimensional parameters (Nusselt, Prandtl and Reynolds numbers). A forced convection scheme with a complex flow field, two dimensional arrays of circular jets with crossflow, was utilized with humidity ratios (mass ratio of water vapor to air) up to 0.23. The dynamic viscosity, thermal conductivity and specific heat of air, steam and air/steam mixtures are examined. Methods for determining gaseous mixture properties from the properties of their pure components are reviewed as well as methods for determining these properties with good confidence. The need for more experimentally determined property data for humid air is discussed. It is concluded that dimensionless forms of forced convection heat transfer data and empirical correlations based on measurements with dry air may be applied to conditions involving humid air with the same confidence as for the dry air case itself, provided that the thermophysical properties of the humid air mixtures are known with the same confidence as their dry air counterparts.

  6. Forced convection heat transfer to air/water vapor mixtures

    NASA Astrophysics Data System (ADS)

    Richards, D. R.; Florschuetz, L. W.

    1984-01-01

    Heat transfer coefficients were measured using both dry and humid air in the same forced convection cooling scheme and were compared using appropriate nondimensional parameters (Nusselt, Prandtl and Reynolds numbers). A forced convection scheme with a complex flow field, two dimensional arrays of circular jets with crossflow, was utilized with humidity ratios (mass ratio of water vapor to air) up to 0.23. The dynamic viscosity, thermal conductivity and specific heat of air, steam and air/steam mixtures are examined. Methods for determining gaseous mixture properties from the properties of their pure components are reviewed as well as methods for determining these properties with good confidence. The need for more experimentally determined property data for humid air is discussed. It is concluded that dimensionless forms of forced convection heat transfer data and empirical correlations based on measurements with dry air may be applied to conditions involving humid air with the same confidence as for the dry air case itself, provided that the thermophysical properties of the humid air mixtures are known with the same confidence as their dry air counterparts.

  7. Calculation of complex equilibria involving vaporization into vacuum

    NASA Technical Reports Server (NTRS)

    Paule, R. C.

    1974-01-01

    A simplified, direct approach is presented to the description of complex equilibria involving vaporization into vacuum. Emphasis is on the basic problem-solving process and on modification of existing techniques. Sequential solutions are presented to problems involving purification of a melt by vaporization into vacuum. The effects of concentration of melt and oxygen partial pressures on vaporization rates are demonstrated.

  8. Heat transfer intensification by increasing vapor flow rate in flat heat pipes

    NASA Astrophysics Data System (ADS)

    Sprinceana, Silviu; Mihai, Ioan; Beniuga, Marius; Suciu, Cornel

    2015-02-01

    Flat heat pipes have various technical applications, one of the most important being the cooling of electronic components[9]. Their continuous development is due to the fact that these devices permit heat transfer without external energetic contribution. The practical exploitation of flat heat pipes however is limited by the fact that dissipated power can only reach a few hundred watts. The present paper aims to advance a new method for the intensification of convective heat transfer. A centrifugal mini impeller, driven by a turntable which incorporates four permanent magnets was designed. These magnets are put in motion by another rotor, which in its turn includes two permanent magnets and is driven by a mini electrical motor. Rotation of the centrifugal blades generates speed and pressure increase of the cooling agent brought to vapor state within the flat micro heat pipe. It's well known that the liquid suffers biphasic transformations during heat transfer inside the heat pipe. Over the hotspot (the heat source being the electronic component) generated at one end of the heat pipe, convective heat transfer occurs, leading to sudden vaporization of the liquid. Pressures generated by newly formed vapors push them towards the opposite end of the flat heat pipe, where a finned mini heat sink is usually placed. The mini-heat exchanger is air-cooled, thus creating a cold spot, where vapors condensate. The proposed method contributes to vapor flow intensification by increasing their transport speed and thus leading to more intense cooling of the heat pipe.

  9. Kinetics of wet sodium vapor complex plasma

    SciTech Connect

    Mishra, S. K.; Sodha, M. S.

    2014-04-15

    In this paper, we have investigated the kinetics of wet (partially condensed) Sodium vapor, which comprises of electrons, ions, neutral atoms, and Sodium droplets (i) in thermal equilibrium and (ii) when irradiated by light. The formulation includes the balance of charge over the droplets, number balance of the plasma constituents, and energy balance of the electrons. In order to evaluate the droplet charge, a phenomenon for de-charging of the droplets, viz., evaporation of positive Sodium ions from the surface has been considered in addition to electron emission and electron/ion accretion. The analysis has been utilized to evaluate the steady state parameters of such complex plasmas (i) in thermal equilibrium and (ii) when irradiated; the results have been graphically illustrated. As a significant outcome irradiated, Sodium droplets are seen to acquire large positive potential, with consequent enhancement in the electron density.

  10. Kinetics of wet sodium vapor complex plasma

    NASA Astrophysics Data System (ADS)

    Mishra, S. K.; Sodha, M. S.

    2014-04-01

    In this paper, we have investigated the kinetics of wet (partially condensed) Sodium vapor, which comprises of electrons, ions, neutral atoms, and Sodium droplets (i) in thermal equilibrium and (ii) when irradiated by light. The formulation includes the balance of charge over the droplets, number balance of the plasma constituents, and energy balance of the electrons. In order to evaluate the droplet charge, a phenomenon for de-charging of the droplets, viz., evaporation of positive Sodium ions from the surface has been considered in addition to electron emission and electron/ion accretion. The analysis has been utilized to evaluate the steady state parameters of such complex plasmas (i) in thermal equilibrium and (ii) when irradiated; the results have been graphically illustrated. As a significant outcome irradiated, Sodium droplets are seen to acquire large positive potential, with consequent enhancement in the electron density.

  11. Excess liquid in heat-pipe vapor spaces

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.; Edwards, D. K.

    1977-01-01

    A mathematical model is developed of excess liquid in heat pipes that is used to calculate the parameters governing the axial flow of liquid in fillets and puddles that form in vapor spaces. In an acceleration field, the hydrostatic pressure variation is taken into account, which results in noncircular meniscus shapes. The two specific vapor-space geometries considered are circular and the 'Dee-shape' that is formed by a slab wick in a circular tube. Also presented are theoretical and experimental results for the conditions under which liquid slugs form at the ends of the vapor spaces. These results also apply to the priming of arteries.

  12. Excess liquid in heat-pipe vapor spaces

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.; Edwards, D. K.

    1977-01-01

    A mathematical model is developed of excess liquid in heat pipes that is used to calculate the parameters governing the axial flow of liquid in fillets and puddles that form in vapor spaces. In an acceleration field, the hydrostatic pressure variation is taken into account, which results in noncircular meniscus shapes. The two specific vapor-space geometries considered are circular and the 'Dee-shape' that is formed by a slab wick in a circular tube. Also presented are theoretical and experimental results for the conditions under which liquid slugs form at the ends of the vapor spaces. These results also apply to the priming of arteries.

  13. Forced convection heat transfer to air/water vapor mixtures

    NASA Technical Reports Server (NTRS)

    Richards, D. R.; Florschuetz, L. W.

    1986-01-01

    Heat transfer coefficients were measured using both dry air and air/water vapor mixtures in the same forced convection cooling test rig (jet array impingement configurations) with mass ratios of water vapor to air up to 0.23. The primary objective was to verify by direct experiment that selected existing methods for evaluation of viscosity and thermal conductivity of air/water vapor mixtures could be used with confidence to predict heat transfer coefficients for such mixtures using as a basis heat transfer data for dry air only. The property evaluation methods deemed most appropriate require as a basis a measured property value at one mixture composition in addition to the property values for the pure components.

  14. Forced convection heat transfer to air/water vapor mixtures

    NASA Technical Reports Server (NTRS)

    Richards, D. R.; Florschuetz, L. W.

    1986-01-01

    Heat transfer coefficients were measured using both dry air and air/water vapor mixtures in the same forced convection cooling test rig (jet array impingement configurations) with mass ratios of water vapor to air up to 0.23. The primary objective was to verify by direct experiment that selected existing methods for evaluation of viscosity and thermal conductivity of air/water vapor mixtures could be used with confidence to predict heat transfer coefficients for such mixtures using as a basis heat transfer data for dry air only. The property evaluation methods deemed most appropriate require as a basis a measured property value at one mixture composition in addition to the property values for the pure components.

  15. Open-cycle vapor compression heat pump

    NASA Astrophysics Data System (ADS)

    Becker, F. E.; Ruggles, A. E.

    1985-03-01

    Large quantities of low-grade energy in the form of low-pressure steam and low-temperature heat are often discharged to the environment by industry. The practical and economical recovery of energy from these sources is often limited by the number of applications that can directly use low-temperature heat. Thermo Electron has developed an open-cycle steam heat pump system capable of the direct recovery and upgrading of low-grade waste energy. The system compresses low-pressure waste steam (or steam made from sources of low-temperature waste heat) to produce high-pressure steam suitable for use in industrial processes. A prototype system has been developed that is capable of recovering and recompressing up to 10,000 lb/hr of waste steam, while using only 50 percent of the fuel that would be required to produce comparable steam in a boiler.

  16. Open-cycle vapor compression heat pump

    NASA Astrophysics Data System (ADS)

    Becker, F. E.; Ruggles, A. E.

    1983-04-01

    Large quantities of low-grade energy are wasted by industry in the form of low-pressure steam and low-temperature heat. The practical and economical recovery of energy from these sources is restricted by the limited number of useful applications for low-grade energy, and is further complicated by contamination of the waste streams. Thermo electron has developed an open-cycle steam heat pump system capable of the direct recovery and upgrading of low-grade waste steam. The system compresses low-pressure waste steam (or steam made from sources of low-temperature waste heat) to produce high-pressure steam suitable for use in industrial processes.

  17. Open cycle vapor compression heat pump

    NASA Astrophysics Data System (ADS)

    Sakhuja, R.; Becker, F. E.

    1980-07-01

    A compressor test facility was built incorporating a screw compressor modified for steam service. The compressor was tested over a wide range of operating conditions with experimental results showing excellent agreement with predicted performance. The compressor operation with wet steam and water injection was completely satisfactory, demonstrating its suitability for use in a steam heat pump system.

  18. Open-cycle vapor compression heat pump

    NASA Astrophysics Data System (ADS)

    Becker, F. E.; Ruggles, A. E.

    1984-05-01

    Large quantities of low-grade energy in the form of low-pressure steam and low-temperature heat are wasted by industry. The practical and economical recovery of energy from these sources is often limited by the number of applications for the use of low-temperature heat. Thermo Electron has developed an open-cycle steam heat pump system capable of the direct recovery and upgrading of low-grade waste steam. The system compresses low-pressure waste steam (or steam made from sources of low-temperature waste heat) to produce high-pressure steam suitable for use in industrial processes. A prototype system was developed that is capable of recovering and recompressing up to 10,000 lb/hr of waste steam, while using only 50 percent of the fuel that would be required to produce comparable steam in a boiler. The prototype steam recompression system, using a 2200-cfm rotary screw compressor driven by a 500-hp natural gas engine, was tested for a yearlong field test.

  19. Potential heat exchange fluids for use in sulfuric acid vaporizers

    NASA Technical Reports Server (NTRS)

    Lawson, D. D.; Petersen, G. R.

    1981-01-01

    A series of liquids have been screened as candidate heat exchange fluids for service in thermochemical cycles that involve the vaporization of sulfuric acid. The required chemical and physical criteria of the liquids is described with the results of some preliminary high temperature test data presented.

  20. Potential heat exchange fluids for use in sulfuric acid vaporizers

    NASA Technical Reports Server (NTRS)

    Lawson, D. D.; Petersen, G. R.

    1979-01-01

    A series of perhalocarbons are proposed as candidate heat exchange fluids for service in thermochemical cycles for hydrogen production that involve direct contact of the fluid with sulfuric acid and vaporization of the acid. The required chemical and physical criteria of the liquids are described and the results of some preliminary high temperature test data are presented.

  1. Open-cycle vapor compression heat pump

    NASA Astrophysics Data System (ADS)

    Becker, F. E.; Ruggles, A. E.

    A prototype gas-fired steam heat pump was developed. The system utilizes a dry screw compressor driven by a 500-hp natural gas industrial engine. The system can recompress 10,000 lb per hr of clean steam over a 3 to 1 pressure ratio. The fuel consumption of this system is approximately 50 percent that of a direct-fired boiler. A similar size system capable of operating with contaminated steam is also being developed.

  2. Vapor-Compression Heat Pumps for Operation Aboard Spacecraft

    NASA Technical Reports Server (NTRS)

    Ruemmele, Warren; Ungar, Eugene; Cornwell, John

    2006-01-01

    Vapor-compression heat pumps (including both refrigerators and heat pumps) of a proposed type would be capable of operating in microgravity and would be safe to use in enclosed environments like those of spacecraft. The designs of these pumps would incorporate modifications of, and additions to, vapor-compression cycles of heat pumps now used in normal Earth gravitation, in order to ensure efficiency and reliability during all phases of operation, including startup, shutdown, nominal continuous operation, and peak operation. Features of such a design might include any or all of the following: (1) Configuring the compressor, condenser, evaporator, valves, capillary tubes (if any), and controls to function in microgravitation; (2) Selection of a working fluid that satisfies thermodynamic requirements and is safe to use in a closed crew compartment; (3) Incorporation of a solenoid valve and/or a check valve to prevent influx of liquid to the compressor upon startup (such influx could damage the compressor); (4) Use of a diode heat pipe between the cold volume and the evaporator to limit the influx of liquid to the compressor upon startup; and (5) Use of a heated block to vaporize any liquid that arrives at the compressor inlet.

  3. Vapor layer evolution during drop impact on a heated surface

    NASA Astrophysics Data System (ADS)

    Lee, Sanghyeon; Lee, Sangjun; Lee, Jisan; Fezzaa, Kamel; Je, Jung Ho

    2015-11-01

    When a liquid drop impacts on a sufficiently hot surface above the boiling point, a vapor layer is formed between the drop and the surface, preventing direct contact between them and as a result levitating the drop, known as the Leidenfrost effect. Understanding the evolution of the vapor layer is largely unexplored despite its importance in estimating heat transfer in cooling systems of thermal or nuclear power plants. The side-profile visualization of the vapor layer, as absolutely required for investigating its evolution, has been however unavailable by conventional optical microscopy. In this study, by employing ultrafast X-ray phase contrast imaging, we directly visualize the profiles of the vapor layers during liquid drop impact on a hot surface and elucidate the evolution of the vapor layers during spreading and retraction of the drop as functions of impact height and surface temperature. We reveal that the evolution is governed by the propagation of capillary waves generated in retraction and the wavelength of capillary waves λ is inversely proportional to the impact height h with a relation ~σ/ρh ~We-1 where We is weber number. Capillary waves that converge at the center of the vapor layers are linked to the bouncing behavior of the drop.

  4. Two-dimensional vapor flow analysis in heat pipes

    SciTech Connect

    Prenger, F.C.; Busse, C.A.

    1984-01-01

    The computer code AGATHE is intended to evaluate axially symmetric heat pipes with compressible vapor flow at Mach numbers up to 1 and at all radial Reynolds numbers. The code can be used to evaluate empirical factors describing turbulence. Furthermore, heat input and output are modeled by describing liquid heat transfer loops. This method leads to nonuniform heating and cooling rates typical of actual heat pipes. Presently the code is adapted to evaluate heat pipes in tubular geometry composed of a series of heat transfer and adiabatic zones of cylindrical or conical shape. In this analysis the two-dimensional mathematical problem was reduced to a number of ordinary differential equations, which are integrated by a Runge-Kutta scheme. The reduction was achieved, first, by starting from the Navier-Stokes equation using the boundary layer approximation; this approximation introduces the main limitation of the code, restricting its use to the calculation of vapor ducts with large length-to-diameter ratios. Second, the velocity profile was simulated by a power series. The n coefficients of this series were determined such that at each axial position the radial pressure gradient was approximately zero, as specified by the boundary layer approximation.

  5. Modeling Vapor and Heat Transport on Io

    NASA Astrophysics Data System (ADS)

    Allen, D. R.; Howell, R. R.

    2012-12-01

    length scales of sulfur deposition that were intermediate between our Ingersoll adapted model and the Moreno scaled lengths. Assumptions that we made in order to simplify our models are likely contributing to the differences in length scales between our radial model and the Moreno model. Results from these sulfur transport models will be presented. In addition to the sulfur transport models, we are beginning to develop models to investigate the role of sulfur in modifying the temperatures. Models of horizontal transport of sulfur in and around the patera and of vertical transport of sulfur from depth within the patera will explore the role of sulfur in modifying the temperatures. Horizontal transport models probe the ability of sulfur to redistribute the heat around the patera creating lower temperatures and uniform temperature profiles. Vertical transport models explore the ability to bring heat from depth and to produce the light deposits in the images. This work was supported in part by NASA JDAP grant NNX09AE06G. References: Ingersoll, A.P. (1989), Io meteorology: How atmospheric pressure is controlled locally by volcanoes and surface frosts, Icarus, 81, 298-313. Moreno, M.A., G. Schubert, J. Baumgardner, M.G. Kivelson, and D.A. Paige (1991), Io's volcanic and sublimation atmospheres, Icarus, 93, 63-81.

  6. The latent heat of vaporization of supercritical fluids

    NASA Astrophysics Data System (ADS)

    Banuti, Daniel; Raju, Muralikrishna; Hickey, Jean-Pierre; Ihme, Matthias

    2016-11-01

    The enthalpy of vaporization is the energy required to overcome intermolecular attractive forces and to expand the fluid volume against the ambient pressure when transforming a liquid into a gas. It diminishes for rising pressure until it vanishes at the critical point. Counterintuitively, we show that a latent heat is in fact also required to heat a supercritical fluid from a liquid to a gaseous state. Unlike its subcritical counterpart, the supercritical pseudoboiling transition is spread over a finite temperature range. Thus, in addition to overcoming intermolecular attractive forces, added energy simultaneously heats the fluid. Then, considering a transition from a liquid to an ideal gas state, we demonstrate that the required enthalpy is invariant to changes in pressure for 0 < p < 3pcr . This means that the classical pressure-dependent latent heat is merely the equilibrium part of the phase transition. The reduction at higher pressures is compensated by an increase in a nonequilibrium latent heat required to overcome residual intermolecular forces in the real fluid vapor during heating. At supercritical pressures, all of the transition occurs at non-equilibrium; for p -> 0 , all of the transition occurs at equilibrium.

  7. Vapor Compression and Thermoelectric Heat Pump Heat Exchangers for a Condensate Distillation System: Design and Experiment

    NASA Technical Reports Server (NTRS)

    Erickson, Lisa R.; Ungar, Eugene K.

    2013-01-01

    Maximizing the reuse of wastewater while minimizing the use of consumables is critical in long duration space exploration. One of the more promising methods of reclaiming urine is the distillation/condensation process used in the cascade distillation system (CDS). This system accepts a mixture of urine and toxic stabilizing agents, heats it to vaporize the water and condenses and cools the resulting water vapor. The CDS wastewater flow requires heating and its condensate flow requires cooling. Performing the heating and cooling processes separately requires two separate units, each of which would require large amounts of electrical power. By heating the wastewater and cooling the condensate in a single heat pump unit, mass, volume, and power efficiencies can be obtained. The present work describes and compares two competing heat pump methodologies that meet the needs of the CDS: 1) a series of mini compressor vapor compression cycles and 2) a thermoelectric heat exchanger. In the paper, the system level requirements are outlined, the designs of the two heat pumps are described in detail, and the results of heat pump performance tests are provided. A summary is provided of the heat pump mass, volume and power trades and a selection recommendation is made.

  8. Cappuccino and Specific Heat versus Heat of Vaporization

    ERIC Educational Resources Information Center

    Hidden, Frits; Boomsma, Jorn; Schins, Anton; van den Berg, Ed

    2012-01-01

    A cappuccino is prepared by adding about 50 mL frothing, foaming milk to a cup of espresso. Whole milk is best for foaming and the ideal milk temperature when adding it to the espresso is 65 [degrees]C. The espresso itself may be warmer than that. During the heating the milk should not burn, as that would spoil the taste. The best way is to heat…

  9. Cappuccino and Specific Heat versus Heat of Vaporization

    ERIC Educational Resources Information Center

    Hidden, Frits; Boomsma, Jorn; Schins, Anton; van den Berg, Ed

    2012-01-01

    A cappuccino is prepared by adding about 50 mL frothing, foaming milk to a cup of espresso. Whole milk is best for foaming and the ideal milk temperature when adding it to the espresso is 65 [degrees]C. The espresso itself may be warmer than that. During the heating the milk should not burn, as that would spoil the taste. The best way is to heat…

  10. The effects of heat conduction on the vaporization of liquid invading superheated permeable rock

    SciTech Connect

    Woods, Andrew, W.; Fitzgerald, Shaun D.

    1996-01-24

    We examine the role of conductive and convective heat transfer in the vaporization of liquid as it slowly invades a superheated permeable rock. For very slow migration, virtually all of the liquid vaporizes. As the liquid supply rate increases beyond the rate of heat transfer by thermal conduction, a decreasing fraction of the liquid can vaporize. Indeed, for sufficiently high flow rates, the fraction vaporizing depends solely on the superheat of the rock, and any heat transfer from the superheated region is negligible. These results complement earlier studies of vaporization under very high injection rates, in which case the dynamic vapour pressure reduces the mass fraction vaporizing to very small values.

  11. Vapor bubble evolution on a heated surface containing open microchannels

    NASA Astrophysics Data System (ADS)

    Forster, Christopher J.; Glezer, Ari; Smith, Marc K.

    2011-11-01

    Power electronics require cooling technologies capable of high heat fluxes at or below the operating temperatures of these devices. Boiling heat transfer is an effective choice for such cooling, but it is limited by the critical heat flux (CHF), which is typically near 125 W/cm2 for pool boiling of water on a flat plate at standard pressure and gravity. One method of increasing CHF is to incorporate an array of microchannels into the heated surface. Microchannels have been experimentally shown to improve CHF, and the goal of this study is to determine the primary mechanisms associated with the microchannels that allow for the increased CHF. While the use of various microstructures is not new, the emphasis of previous work has been on heat transfer aspects, as opposed to the fluid dynamics inside and in the vicinity of the microchannels. This work considers the non-isothermal fluid motion during bubble growth and departure by varying channel geometry, spacing, and heat flux input using a level-set method including vaporization and condensation. These results and the study of the underlying mechanisms will aid in the design optimization of microchannel-based cooling devices. Supported by ONR.

  12. Vapor hydrogen peroxide as alternative to dry heat microbial reduction

    NASA Astrophysics Data System (ADS)

    Chung, S.; Kern, R.; Koukol, R.; Barengoltz, J.; Cash, H.

    The Jet Propulsion Laboratory in conjunction with the NASA Planetary Protection Officer has selected vapor phase hydrogen peroxide sterilization process for continued development as a NASA approved sterilization technique for spacecraft subsystems and systems The goal is to include this technique with appropriate specification in NPG8020 12C as a low temperature complementary technique to the dry heat sterilization process To meet microbial reduction requirements for all Mars in-situ life detection and sample return missions various planetary spacecraft subsystems will have to be exposed to a qualified sterilization process This process could be the elevated temperature dry heat sterilization process 115C for 40 hours which was used to sterilize the Viking lander spacecraft However with utilization of highly sophisticated electronics and sensors in modern spacecraft this process presents significant materials challenges and is thus undesirable to design engineers to achieve bioburden reduction The objective of this work is to introduce vapor hydrogen peroxide VHP as an alternative to dry heat microbial reduction to meet planetary protection requirements The VHP process is widely used by the medical industry to sterilize surgical instruments and biomedical devices but high doses of VHP may degrade the performance of flight hardware or compromise material compatibility Our goal for this study is to determine the minimum VHP process conditions for planetary protection acceptable microbial reduction levels A series of experiments were conducted to

  13. Vapor Shielding of Solid Targets Exposed to High Heat Flux

    NASA Astrophysics Data System (ADS)

    Pshenov, A. A.; Eksaeva, A. A.; Krasheninnikov, S. I.; Marenkov, E. D.

    The thickness of Tungsten monoblocks composing the future ITER divertor is supposed to be 8 mm only. Therefore, severe erosion caused by high heat fluxes during transients, such as Type I ELMs and disruptions, is a limiting factor to PFCs lifespan. Under the influence of extreme heat fluxes expected during ITER transients serious surface modification of the Tungsten monoblocks is anticipated. Moreover, melting of a thin surface layer is likely to happen. Melt motion contributes seriously to the material erosion. The other sources of erosion are melt splashing, in the form of droplet ejection, and evaporation. These mechanics lead to a cold dense secondary plasma region formation near the irradiated surface. Intense re-radiation of the incoming plasma flow energy in the secondary plasma layer results in a significant reduction of the heat flux reaching the target surface. Accounting for this vapor shielding effect is essential to estimate the surface erosion under influence of intense plasma flow properly. In this paper a simple model capable of reproducing one of the key features of vapor shielding, namely the saturation of the energy absorbed by the target, is proposed. This model allows for an approximate analytical solution that indicates parameters the saturation energy depends on. The model is validated against the experimental data obtained at MK-200 pulse plasma accelerator.

  14. Liquid flow and vapor formation phenomena in a flat heat pipe

    SciTech Connect

    McCreery, G.E.

    1994-10-01

    The design and construction of a novel heat pipe apparatus is described, and results from experiments that employed the apparatus are presented. the apparatus is designed to permit visual and photographic study of liquid flow and vapor formation within the heat pipe wick structure, artery, and vapor flow channel. The vapor temperature field in the vapor flow channel is displayed by use of thermochromic liquid crystal material. Liquid and vapor flow phenomenon observed during normal and the approach to boiling-limited heat pipe operation are described.

  15. Effect of layering on NAPL behavior in soil heated vapor extraction

    SciTech Connect

    Webb, S.W.; Phelan, J.M.

    1995-12-31

    Soil heating has been proposed as a method to enhance the vapor extraction of NAPLs from contaminated soils. While vapor extraction without heating is effective in removing those NAPLs with relatively high vapor pressure, it is less successful in removing lower vapor pressure NAPLs. If heat is added to the soil, the efficiency of vapor extraction, especially for the lower vapor pressure NAPLs, is increased due to the higher vapor pressure. Simulations of soil-heated vapor extraction have been performed using a modified version of the TOUGH2 computer program, which models fluid flow and heat transport in porous and fractured media including unsaturated conditions. The original TOUGH2 program evaluates fluid flow and heat transport for water and air fluids. Recent modifications to the code include the capability to simulate a single-component NAPL in addition to the water and air components already present. Three-dimensional models of TEVES have been developed to determine the transient system performance and the potential for contaminant migration. Soil layering has been considered in evaluation of the initial NAPL distribution and in evaporation and transport to the vapor extraction location. Results from this layered model are compared to results for a homogeneous system showing a degradation in NAPL removal efficiency due to layering and the importance of vapor diffusion in transporting VOCs from the lower permeability layers to the higher permeability layers and subsequently to the vapor extraction location.

  16. Overall Heat and Mass Transfer Coefficient of Water Vapor Adsorption

    NASA Astrophysics Data System (ADS)

    Hamamoto, Yoshinori; Mori, Hideo; Godo, Masazumi; Miura, Kunio; Watanabe, Yutaka; Ishizawa, Toshihiko; Takatsuka, Takeshi

    A fundamental investigation was performed to develop a compact and simple desiccant ventilation unit which is one of the main components of a novel energy saving air-conditioning system. Water vapor in the air is adsorbed and/or desorbed to be controlled the humidity of supply air through a unit of an adsorbent rotor. A numerical simulation helps to understand the phenomena of heat and mass transfer in the rotor block. Overall transfer coefficients were estimated by performing both experiment and calculation. It was examined that the transient overall equivalent heat and mass transfer coefficient was not constant. It seems that both film fluid and diffusion resistance govern the coefficients in the block, and the influence of air flow on the time averaged coefficients is estimated by a considering the laminar forced convection from a flat plate. There is little difference of the coefficient between adsorption and desorption process. The correlation and fitting parameters are presented for prediction of the overall heat and mass transfer coefficients. The estimation accuracy was improved.

  17. Vapor Hydrogen Peroxide as Alternative to Dry Heat Microbial Reduction

    NASA Technical Reports Server (NTRS)

    Cash, Howard A.; Kern, Roger G.; Chung, Shirley Y.; Koukol, Robert C.; Barengoltz, Jack B.

    2006-01-01

    The Jet Propulsion Laboratory, in conjunction with the NASA Planetary Protection Officer, has selected vapor phase hydrogen peroxide (VHP) sterilization process for continued development as a NASA approved sterilization technique for spacecraft subsystems and systems. The goal is to include this technique, with appropriate specification, in NPG8020.12C as a low temperature complementary technique to the dry heat sterilization process. A series of experiments were conducted in vacuum to determine VHP process parameters that provided significant reductions in spore viability while allowing survival of sufficient spores for statistically significant enumeration. With this knowledge of D values, sensible margins can be applied in a planetary protection specification. The outcome of this study provided an optimization of test sterilizer process conditions: VHP concentration, process duration, a process temperature range for which the worst case D value may be imposed, a process humidity range for which the worst case D value may be imposed, and robustness to selected spacecraft material substrates.

  18. Vapor Hydrogen Peroxide as Alternative to Dry Heat Microbial Reduction

    NASA Technical Reports Server (NTRS)

    Cash, Howard A.; Kern, Roger G.; Chung, Shirley Y.; Koukol, Robert C.; Barengoltz, Jack B.

    2006-01-01

    The Jet Propulsion Laboratory, in conjunction with the NASA Planetary Protection Officer, has selected vapor phase hydrogen peroxide (VHP) sterilization process for continued development as a NASA approved sterilization technique for spacecraft subsystems and systems. The goal is to include this technique, with appropriate specification, in NPG8020.12C as a low temperature complementary technique to the dry heat sterilization process. A series of experiments were conducted in vacuum to determine VHP process parameters that provided significant reductions in spore viability while allowing survival of sufficient spores for statistically significant enumeration. With this knowledge of D values, sensible margins can be applied in a planetary protection specification. The outcome of this study provided an optimization of test sterilizer process conditions: VHP concentration, process duration, a process temperature range for which the worst case D value may be imposed, a process humidity range for which the worst case D value may be imposed, and robustness to selected spacecraft material substrates.

  19. Bilateral heat exchange in vaporization channels with an inner spirally coiled tube

    NASA Astrophysics Data System (ADS)

    Budov, V. M.; Dmitriev, S. M.

    1989-02-01

    Analytical expressions have been obtained for the profiles of the coolant temperatures and the enthalpy of the heated medium along the length of a vaporization channel with twisted flow, in the case of bilateral heating with forward and reverse motion.

  20. Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, July 1 - September 31, 1996

    SciTech Connect

    Suuberg, E.M.; Oja, V.; Lilly, W.D.

    1996-12-31

    The vapor pressure correlations that exist at present for coal tars are very crude and they are not considered reliable to even an order of magnitude. This project seeks to address this important gap in the near term by direct measurement of vapor pressures of coal tar fractions, by application of well-established techniques and modifications thereof. The principal objectives of the program are to: (1) obtain data on the vapor pressures and heats of vaporization of tars from a range of ranks of coal; (2) develop correlations based on a minimum set of conveniently measurable characteristics of the tars; and (3) develop equipment that would allow performing such measurements in a reliable, straightforward fashion. During this quarter we have extended the work on measurements of vapor pressures of coal tars, using the continuous Knudsen effusion technique. These results need further analysis and therefore in this report we describe only the general idea behind the technique, and also show some typical results.

  1. Heat Transfer in Complex Fluids

    SciTech Connect

    Mehrdad Massoudi

    2012-01-01

    Amongst the most important constitutive relations in Mechanics, when characterizing the behavior of complex materials, one can identify the stress tensor T, the heat flux vector q (related to heat conduction) and the radiant heating (related to the radiation term in the energy equation). Of course, the expression 'complex materials' is not new. In fact, at least since the publication of the paper by Rivlin & Ericksen (1955), who discussed fluids of complexity (Truesdell & Noll, 1992), to the recently published books (Deshpande et al., 2010), the term complex fluids refers in general to fluid-like materials whose response, namely the stress tensor, is 'non-linear' in some fashion. This non-linearity can manifest itself in variety of forms such as memory effects, yield stress, creep or relaxation, normal-stress differences, etc. The emphasis in this chapter, while focusing on the constitutive modeling of complex fluids, is on granular materials (such as coal) and non-linear fluids (such as coal-slurries). One of the main areas of interest in energy related processes, such as power plants, atomization, alternative fuels, etc., is the use of slurries, specifically coal-water or coal-oil slurries, as the primary fuel. Some studies indicate that the viscosity of coal-water mixtures depends not only on the volume fraction of solids, and the mean size and the size distribution of the coal, but also on the shear rate, since the slurry behaves as shear-rate dependent fluid. There are also studies which indicate that preheating the fuel results in better performance, and as a result of such heating, the viscosity changes. Constitutive modeling of these non-linear fluids, commonly referred to as non-Newtonian fluids, has received much attention. Most of the naturally occurring and synthetic fluids are non-linear fluids, for example, polymer melts, suspensions, blood, coal-water slurries, drilling fluids, mud, etc. It should be noted that sometimes these fluids show Newtonian

  2. Dielectric and specific heat relaxations in vapor deposited glycerol.

    PubMed

    Kasina, A; Putzeys, T; Wübbenhorst, M

    2015-12-28

    Recently [S. Capponi, S. Napolitano, and M. Wübbenhorst, Nat. Commun. 3, 1233 (2012)], vapor deposited glasses of glycerol have been found to recover their super-cooled liquid state via a metastable, ordered liquid (MROL) state characterized by a tremendously enhanced dielectric strength along with a slow-down of the relaxation rate of the structural relaxation. To study the calorimetric signature of this phenomenon, we have implemented a chip-based, differential AC calorimeter in an organic molecular beam deposition setup, which allows the simultaneous measurement of dielectric relaxations via interdigitated comb electrodes and specific heat relaxation spectra during deposition and as function of the temperature. Heating of the as-deposited glass just above the bulk Tg and subsequent cooling/reheating revealed a step-wise increase in cp by in total 9%, indicating unambiguously that glycerol, through slow vapour deposition, forms a thermodynamically stable glass, which has a specific heat as low as that of crystalline glycerol. Moreover, these glasses were found to show excellent kinetic stability as well as evidenced by both a high onset-temperature and quasi-isothermal recovery measurements at -75 °C. The second goal of the study was to elucidate the impact of the MROL state on the specific heat and its relaxation to the super-cooled state. Conversion of "MROL glycerol" to its "normal" (ordinary liquid, OL) state revealed a second, small (∼2%) increase of the glassy cp, a little gain (<10%) in the relaxed specific heat, and no signs of deviations of τcal from that of normal "bulk" glycerol. These findings altogether suggest that the MROL state in glycerol comprises largely bulk-type glycerol that coexist with a minor volume fraction (<10%) of PVD-induced structural anomalies with a crystal-like calorimetric signature. Based on the new calorimetric findings, we have proposed a new physical picture that assumes the existence of rigid polar clusters (RPCs

  3. Dielectric and specific heat relaxations in vapor deposited glycerol

    NASA Astrophysics Data System (ADS)

    Kasina, A.; Putzeys, T.; Wübbenhorst, M.

    2015-12-01

    Recently [S. Capponi, S. Napolitano, and M. Wübbenhorst, Nat. Commun. 3, 1233 (2012)], vapor deposited glasses of glycerol have been found to recover their super-cooled liquid state via a metastable, ordered liquid (MROL) state characterized by a tremendously enhanced dielectric strength along with a slow-down of the relaxation rate of the structural relaxation. To study the calorimetric signature of this phenomenon, we have implemented a chip-based, differential AC calorimeter in an organic molecular beam deposition setup, which allows the simultaneous measurement of dielectric relaxations via interdigitated comb electrodes and specific heat relaxation spectra during deposition and as function of the temperature. Heating of the as-deposited glass just above the bulk Tg and subsequent cooling/reheating revealed a step-wise increase in cp by in total 9%, indicating unambiguously that glycerol, through slow vapour deposition, forms a thermodynamically stable glass, which has a specific heat as low as that of crystalline glycerol. Moreover, these glasses were found to show excellent kinetic stability as well as evidenced by both a high onset-temperature and quasi-isothermal recovery measurements at -75 °C. The second goal of the study was to elucidate the impact of the MROL state on the specific heat and its relaxation to the super-cooled state. Conversion of "MROL glycerol" to its "normal" (ordinary liquid, OL) state revealed a second, small (˜2%) increase of the glassy cp, a little gain (<10%) in the relaxed specific heat, and no signs of deviations of τcal from that of normal "bulk" glycerol. These findings altogether suggest that the MROL state in glycerol comprises largely bulk-type glycerol that coexist with a minor volume fraction (<10%) of PVD-induced structural anomalies with a crystal-like calorimetric signature. Based on the new calorimetric findings, we have proposed a new physical picture that assumes the existence of rigid polar clusters (RPCs) and

  4. Vapor hydrogen peroxide as alternative to dry heat microbial reduction

    NASA Astrophysics Data System (ADS)

    Chung, S.; Kern, R.; Koukol, R.; Barengoltz, J.; Cash, H.

    2008-09-01

    The Jet Propulsion Laboratory (JPL), in conjunction with the NASA Planetary Protection Officer, has selected vapor phase hydrogen peroxide (VHP) sterilization process for continued development as a NASA approved sterilization technique for spacecraft subsystems and systems. The goal was to include this technique, with an appropriate specification, in NASA Procedural Requirements 8020.12 as a low-temperature complementary technique to the dry heat sterilization process. The VHP process is widely used by the medical industry to sterilize surgical instruments and biomedical devices, but high doses of VHP may degrade the performance of flight hardware, or compromise material compatibility. The goal for this study was to determine the minimum VHP process conditions for planetary protection acceptable microbial reduction levels. Experiments were conducted by the STERIS Corporation, under contract to JPL, to evaluate the effectiveness of vapor hydrogen peroxide for the inactivation of the standard spore challenge, Geobacillus stearothermophilus. VHP process parameters were determined that provide significant reductions in spore viability while allowing survival of sufficient spores for statistically significant enumeration. In addition to the obvious process parameters of interest: hydrogen peroxide concentration, number of injection cycles, and exposure duration, the investigation also considered the possible effect on lethality of environmental parameters: temperature, absolute humidity, and material substrate. This study delineated a range of test sterilizer process conditions: VHP concentration, process duration, a process temperature range for which the worst case D-value may be imposed, a process humidity range for which the worst case D-value may be imposed, and the dependence on selected spacecraft material substrates. The derivation of D-values from the lethality data permitted conservative planetary protection recommendations.

  5. Analysis of the one-dimensional transient compressible vapor flow in heat pipes

    NASA Technical Reports Server (NTRS)

    Jang, Jong H.; Faghri, Amir; Chang, Won S.

    1991-01-01

    The transient compressible one-dimensional vapor flow dynamics in a heat pipe is modeled. The numerical results are obtained by using the implicit non-iterative Beam-Warming finite difference method. The model is tested for simulated heat pipe vapor flow and actual vapor flow in cylindrical heat pipes. A good comparison of the present transient results for the simulated heat pipe vapor flow with the previous results of a two-dimensional numerical model is achieved and the steady state results are in agreement with the existing experimental data. The transient behavior of the vapor flow under subsonic, sonic, and supersonic speeds as well as high mass flow rates are successfully predicted.

  6. Heat transfer by condensation of low pressure metal vapors.

    NASA Technical Reports Server (NTRS)

    Huang, Y. S.; Lyman, F. A.; Lick, W. J.

    1972-01-01

    The film condensation of low pressure metal vapors on isothermal vertical flat plates or tubes is considered. The liquid film is treated as a thin layer in which the acceleration and pressure forces are negligible and across which the temperature distribution is linear. The average behavior of the vapor is found from the linearized one-dimensional vapor flow equations. In order to calculate the rate of condensation, a consistent distribution function for the vapor particles at the liquid-vapor interface is necessary and is determined. The result of the analysis is a set of algebraic equations from which one can predict the condensation rate of low pressure metal vapors. A large but continuous temperature decrease in the vapor is predicted and calculated.

  7. Heat transfer enhancement of a steam condensation by mixing ethanol vapor

    SciTech Connect

    Utaka, Yoshio; Kenmotsu, Tatsuya; Kobayashi; Hironori

    1999-07-01

    The heat transfer enhancement of ethanol vapor mixing into steam were investigated. First, it was shown that the influence of the cooling intensity revealed themselves remarkably on the heat transfer rate and the modes of condensate varied with the change in cooling intensity. The effect could be shown as the condensation characteristic curve (Marangoni condensation curve) that exhibited the variation of the heat flux or the heat transfer coefficient against the surface subcooling. It was also confirmed that the enhancement effect of the heat transfer is considerable by using the mixing of small quantities of ethanol vapor into steam. Next, the effect of principal conditions such as the vapor concentration, the vapor velocity and the height of heat transfer surface on the condensation characteristic curves for the vapor mixture of water-ethanol were clarified. As a result, the maximum peak value of the heat transfer coefficient appeared at about ethanol vapor mass fraction of 0.05 due to the experiment of varying ethanol concentration. The condensation characteristic curve moved parallel to the axis of the heat transfer coefficient with increasing vapor velocity. The effect of vapor velocity acted as the reduction of the diffusion resistance in the vapor layer for relatively small surface subcooling region and the reduction of the condensate resistance in the region of the steep increase and transition regions. Although the peak value of the heat transfer coefficient decreased with increasing distance from the top of the condensing surface, the heat transfer coefficient was independent on the position of the surface in the steep increase region.

  8. Experimental determination of ablation vapor species from carbon phenolic heat-shield materials

    NASA Technical Reports Server (NTRS)

    Lincoln, K. A.

    1981-01-01

    The relative concentrations of vapors produced from carbon phenolic composites under thermal loadings approximating those expected at peak heating during vehicle entry into the atmospheres of the outer planets have been determined. The technique of vaporizing the surface of bulk samples by laser irradiation while measuring in situ the vapor species by mass spectrometry is described. Results show that vapor composition varies with irradiance level and with depth of heating (or extent of pyrolysis). Attempts are made to compare these experimental results with the theoretical predictions from computer codes.

  9. Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, April 1--June 30, 1995

    SciTech Connect

    Suuberg, E.M.

    1995-10-01

    The vapor pressure correlations that exist at present for coal tars are very crude and they are not considered reliable to even an order of magnitude when applied to tars. The present project seeks to address this important gap in the near term by direct measurement of vapor pressures of coal tar fractions, by application of well-established techniques and modifications thereof. The principal objectives of the program are to: (1) obtain data on the vapor pressures and heats of vaporization of tars from a range of ranks of coal, (2) develop correlations based on a minimum set of conveniently measurable characteristics of the tars, (3) develop equipment that would allow performing such measurements in a reliable, straightforward fashion. Both the gas saturation method and the Knudsen effusion method are being used. Results are presented for anthracene, naphthacene, pentacene, and a mixture of anthracene and perylene obtained using the effusion method.

  10. Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, 1 January 1996--31 March 1996

    SciTech Connect

    Suuberg, E.M.

    1996-09-01

    The vapor pressure correlations that exist at present for coal tars are very crude and they are not considered reliable to even an order of magnitude. Sophisticated general correlative approaches are slowly being developed, based upon group contribution methods, or based upon some key functional features of the molecules. These are as yet difficult to apply to coal tars. The detailed group contribution methods, in which fairly precise structural information is needed, do not lend themselves well for application to very complex, poorly characterized coal tars. The methods based upon more global types of characterizations have not yet dealt much with the question of oxygenated functional groups. In short, only very limited correlations exist, and these are not considered reliable to even an order of magnitude when applied to tars. The present project seeks to address this important gap in the near term by direct measurement of vapor pressures of coal tar fractions, by application of well- established techniques and modifications thereof. The principal objectives of the program are to: (1) obtain data on the vapor pressures and heats of vaporization of tars from a range of ranks of coal, (2) develop correlations based on a minimum set of conveniently measurable characteristics of the tars, (3) develop equipment that would allow performing such measurements in a reliable, straightforward fashion. A significant amount of time has been devoted during this quarter to developing techniques for measurements of vapor pressures of coal tar related compounds, and mixtures, in a ``continuous`` mode, using the effusion technique.

  11. A non-equilibrium model for soil heating and moisture transport during extreme surface heating: The soil (heat-moisture-vapor) HMV-Model Version

    Treesearch

    William Massman

    2015-01-01

    Increased use of prescribed fire by land managers and the increasing likelihood of wildfires due to climate change require an improved modeling capability of extreme heating of soils during fires. This issue is addressed here by developing and testing the soil (heat-moisture-vapor) HMVmodel, a 1-D (one-dimensional) non-equilibrium (liquid- vapor phase change)...

  12. Dielectric and specific heat relaxations in vapor deposited glycerol

    SciTech Connect

    Kasina, A. E-mail: wubbenhorst@fys.kuleuven.be; Putzeys, T.; Wübbenhorst, M. E-mail: wubbenhorst@fys.kuleuven.be

    2015-12-28

    Recently [S. Capponi, S. Napolitano, and M. Wübbenhorst, Nat. Commun. 3, 1233 (2012)], vapor deposited glasses of glycerol have been found to recover their super-cooled liquid state via a metastable, ordered liquid (MROL) state characterized by a tremendously enhanced dielectric strength along with a slow-down of the relaxation rate of the structural relaxation. To study the calorimetric signature of this phenomenon, we have implemented a chip-based, differential AC calorimeter in an organic molecular beam deposition setup, which allows the simultaneous measurement of dielectric relaxations via interdigitated comb electrodes and specific heat relaxation spectra during deposition and as function of the temperature. Heating of the as-deposited glass just above the bulk T{sub g} and subsequent cooling/reheating revealed a step-wise increase in c{sub p} by in total 9%, indicating unambiguously that glycerol, through slow vapour deposition, forms a thermodynamically stable glass, which has a specific heat as low as that of crystalline glycerol. Moreover, these glasses were found to show excellent kinetic stability as well as evidenced by both a high onset-temperature and quasi-isothermal recovery measurements at −75 °C. The second goal of the study was to elucidate the impact of the MROL state on the specific heat and its relaxation to the super-cooled state. Conversion of “MROL glycerol” to its “normal” (ordinary liquid, OL) state revealed a second, small (∼2%) increase of the glassy c{sub p}, a little gain (<10%) in the relaxed specific heat, and no signs of deviations of τ{sub cal} from that of normal “bulk” glycerol. These findings altogether suggest that the MROL state in glycerol comprises largely bulk-type glycerol that coexist with a minor volume fraction (<10%) of PVD-induced structural anomalies with a crystal-like calorimetric signature. Based on the new calorimetric findings, we have proposed a new physical picture that assumes the

  13. Vaporization heat transfer of dielectric liquids on a wick-covered surface

    NASA Technical Reports Server (NTRS)

    Gu, C. B.; Chow, L. C.; Baker, K.

    1993-01-01

    Vaporization heat transfer characteristics were measured for the dielectric liquid FC-72 on a horizontal heated surface covered with wire screen wicks with the mesh number for the screens varying from 24 to 100. In such a situation the liquid level can be either higher or lower than the heated surface. When the liquid level was above the heated surface (shallow pool boiling), the height of the liquid level above the surface, h, was varied from 0 to 10 mm. When the liquid level was below the heated surface (evaporation through capillary pumping), the distance from the liquid level to the edge of the surface, L, was adjusted from 0 to 15 mm. Experimental data revealed that the critical heat flux (CHF) decreases as the mesh number is increased from 24 to 100 for both vaporation and shallow pool boiling, showing that the vapor-escaping limit is more important than the capillary limit in flat plate heat pipe application.

  14. Vaporization heat transfer of dielectric liquids on a wick-covered surface

    NASA Technical Reports Server (NTRS)

    Gu, C. B.; Chow, L. C.; Baker, K.

    1993-01-01

    Vaporization heat transfer characteristics were measured for the dielectric liquid FC-72 on a horizontal heated surface covered with wire screen wicks with the mesh number for the screens varying from 24 to 100. In such a situation the liquid level can be either higher or lower than the heated surface. When the liquid level was above the heated surface (shallow pool boiling), the height of the liquid level above the surface, h, was varied from 0 to 10 mm. When the liquid level was below the heated surface (evaporation through capillary pumping), the distance from the liquid level to the edge of the surface, L, was adjusted from 0 to 15 mm. Experimental data revealed that the critical heat flux (CHF) decreases as the mesh number is increased from 24 to 100 for both vaporation and shallow pool boiling, showing that the vapor-escaping limit is more important than the capillary limit in flat plate heat pipe application.

  15. Performance of multiple mini-tube heat exchangers as an internal heat exchanger of a vapor-injection cycle heat pump

    NASA Astrophysics Data System (ADS)

    Jang, Jin Yong; Jeong, Ji Hwan

    2016-04-01

    A multiple mini-tube (MMT) heat exchanger was considered as an internal heat exchanger of vapor-injection cycle heat pump. Heat transfer and pressure drop in multiple mini-tube heat exchangers were numerically and experimentally investigated. Results show that the best performance of the MMT heat exchanger can be obtained when the intermediate-pressure two-phase refrigerant is supplied to the shell-side and this refrigerant reaches a saturated vapor state at the exit of the heat exchanger.

  16. Numerical Modeling of Liquid-Vapor Coupled Heat and Fluid Flow in Geothermal Reservoirs

    NASA Astrophysics Data System (ADS)

    Zhang, J.; Xing, H.

    2011-12-01

    Liquid-vapor two phase flows in porous media are complex dynamic processes involving phase transitions and phase production due to concurrent processes. The coupled thermo fluid flow with liquid-vapor phase change has received increasing concern recently due to the highly nonlinear behaviors and drastic changes of physical properties. A numerical model is developed for simulating liquid/vapor two-phase coupled fluid and heat flow in porous media, particularly towards hydrothermal/geothermal reservoirs. The model is formulated by two nonlinear equations with pressure and enthalpy as the primary variables. The nonlinearities in the coupled partial differential equations as well as the severe oscillations and instabilities existing in the numerical modeling are investigated. The coupled highly nonlinear equations are solved simultaneously using a Newton based nonlinear finite element technique with the support of a phase change control module and an automatic time step control module. Numerical results are presented to illustrate the effectiveness and usefulness of the proposed model and algorithms.

  17. Monte Carlo molecular simulation predictions for the heat of vaporization of acetone and butyramide.

    SciTech Connect

    Biddy, Mary J.; Martin, Marcus Gary

    2005-03-01

    Vapor pressure and heats of vaporization are computed for the industrial fluid properties simulation challenge (IFPSC) data set using the Towhee Monte Carlo molecular simulation program. Results are presented for the CHARMM27 and OPLS-aa force fields. Once again, the average result using multiple force fields is a better predictor of the experimental value than either individual force field.

  18. Experimental investigation of the latent heat of vaporization in aqueous nanofluids

    NASA Astrophysics Data System (ADS)

    Lee, Soochan; Phelan, Patrick E.; Dai, Lenore; Prasher, Ravi; Gunawan, Andrey; Taylor, Robert A.

    2014-04-01

    This paper reports an experimental investigation of the latent heat of vaporization (hfg) in nanofluids. Two different types of nanoparticles, graphite and silver, suspended in deionized water were exposed to a continuous laser beam (130 mW, 532 nm) to generate boiling. The latent heat of vaporization in the nanofluids was determined by the measured vapor mass generation and the heat input. To ensure that the measured hfg values are independent of heating method, the experiments were repeated with an electrically heated hot wire as a primary heat input. These experiments show considerable variation in the hfg of nanofluids. That is, graphite nanofluid exhibits an increased hfg and silver nanofluid shows a decrease in hfg compared to the value for pure water. As such, these results indicate that relatively low mass fractions of nanoparticles can apparently create large changes in hfg.

  19. Experimental investigation of the latent heat of vaporization in aqueous nanofluids

    SciTech Connect

    Lee, Soochan; Phelan, Patrick E. Dai, Lenore; Prasher, Ravi; Gunawan, Andrey; Taylor, Robert A.

    2014-04-14

    This paper reports an experimental investigation of the latent heat of vaporization (h{sub fg}) in nanofluids. Two different types of nanoparticles, graphite and silver, suspended in deionized water were exposed to a continuous laser beam (130 mW, 532 nm) to generate boiling. The latent heat of vaporization in the nanofluids was determined by the measured vapor mass generation and the heat input. To ensure that the measured h{sub fg} values are independent of heating method, the experiments were repeated with an electrically heated hot wire as a primary heat input. These experiments show considerable variation in the h{sub fg} of nanofluids. That is, graphite nanofluid exhibits an increased h{sub fg} and silver nanofluid shows a decrease in h{sub fg} compared to the value for pure water. As such, these results indicate that relatively low mass fractions of nanoparticles can apparently create large changes in h{sub fg}.

  20. Heats of vaporization of room temperature ionic liquids by tunable vacuum ultraviolet photoionization

    SciTech Connect

    Chambreau, Steven D.; Vaghjiani, Ghanshyam L.; To, Albert; Koh, Christine; Strasser, Daniel; Kostko, Oleg; Leone, Stephen R.

    2009-11-25

    The heats of vaporization of the room temperature ionic liquids (RTILs) N-butyl-N-methylpyrrolidinium bistrifluorosulfonylimide, N-butyl-N-methylpyrrolidinium dicyanamide, and 1-butyl-3-methylimidazolium dicyanamide are determined using a heated effusive vapor source in conjunction with single photon ionization by a tunable vacuum ultraviolet synchrotron source. The relative gas phase ionic liquid vapor densities in the effusive beam are monitored by clearly distinguished dissociative photoionization processes via a time-of-flight mass spectrometer at a tunable vacuum ultraviolet beamline 9.0.2.3 (Chemical Dynamics Beamline) at the Advanced Light Source synchrotron facility. Resulting in relatively few assumptions, through the analysis of both parent cations and fragment cations, the heat of vaporization of N-butyl-N-methylpyrrolidinium bistrifluorosulfonylimide is determined to be Delta Hvap(298.15 K) = 195+-19 kJ mol-1. The observed heats of vaporization of 1-butyl-3-methylimidazolium dicyanamide (Delta Hvap(298.15 K) = 174+-12 kJ mol-1) and N-butyl-N-methylpyrrolidinium dicyanamide (Delta Hvap(298.15 K) = 171+-12 kJ mol-1) are consistent with reported experimental values using electron impact ionization. The tunable vacuum ultraviolet source has enabled accurate measurement of photoion appearance energies. These appearance energies are in good agreement with MP2 calculations for dissociative photoionization of the ion pair. These experimental heats of vaporization, photoion appearance energies, and ab initio calculations corroborate vaporization of these RTILs as intact cation-anion ion pairs.

  1. Combined vapor compression/absorption heat pump cycles for engine-driven heat pumps

    NASA Astrophysics Data System (ADS)

    Radermacher, Reinhard; Herold, Keith E.; Howe, Lawrence A.

    1988-12-01

    The performance of three combined absorption/vapor compression cycles for gas-fired internal combustion engine driven heat pumps was theoretically assessed. Two cycles were selected for the preliminary design of breadboard systems using only off-the-shelf components. The first cycle, based on the working pair ammonia/water, is termed the simple-cycle. The second cycle, based on the working pair lithium-bromide/water, is termed the compressor enhanced double-effect chiller. Both cycles are found to be technically feasible. The coefficient of performance and the capacity are increased by up to 21 percent for cooling in the first case (compressor efficiency of 0.7) and by up to 14 percent in the second (compressor efficiency of 0.5). Both were compared against the engine drive R22 vapor compression heat pump. The performance of actual machinery for both cycles is, in the current design, hampered by the fact that the desired oil-free compressors have poor isentropic efficiencies. Oil lubricated compressors together with very effective oil separators would improve the performance of the combined LiBr/water cycle to 23 percent.

  2. A first-order estimate of shock heating and vaporization in oceanic impacts

    NASA Technical Reports Server (NTRS)

    Croft, S. K.

    1982-01-01

    The vaporization of water in oceanic impacts of asteroids or comets of multikilometer dimensions is estimated by a semianalytical modeling of impact heating and shock isobar geometry that is based on computer code calculations. The mass of water vaporized in an infinitely deep ocean by the impact of a 10 km diameter asteroid at 25 km/sec (these values have been proposed for the Cretaceous/Tertiary extinction bolide) is approximately equal to the total mass of water vapor present in the earth's atmosphere, and 3-4 orders of magnitude larger than the mass of water vapor in the stratosphere. For projectiles of this size, however, the finite depth of the ocean becomes significant and may considerably reduce the amount of water vapor initially generated by the impact. Climatological models and extinction scenarios invoking the effects of impact-generated water vapor may critically depend on the a priori ambiguous details of the hypothesized impact.

  3. Characteristics of low-temperature short heat pipes with a nozzle-shaped vapor channel

    NASA Astrophysics Data System (ADS)

    Seryakov, A. V.

    2016-01-01

    This paper presents the results of experimental and numerical studies of heat transfer and swirling pulsating flows in short low-temperature heat pipes whose vapor channels have the form of a conical nozzle. It has been found that as the evaporator of the heat pipe is heated, pressure pulsations occur in the vapor channel starting at a certain threshold value of the heat power, which is due to the start of boiling in the evaporator. The frequency of the pulsations has been measured, and their dependence on the superheat of the evaporator has been determined. It has been found that in heat pipes with a conical vapor channel, pulsations occur at lower evaporator superheats and the pulsation frequency is greater than in heat pipes of the same size with a standard cylindrical vapor channel. It has been shown that the curve of the heat-transfer coefficient versus thermal load on the evaporator has an inflection corresponding to the start of boiling in the capillary porous evaporator of the heat pipe.

  4. Drying of pulverized material with heated condensible vapor

    DOEpatents

    Carlson, Larry W.

    1986-01-01

    Apparatus for drying pulverized material utilizes a high enthalpy condensable vapor such as steam for removing moisture from the individual particles of the pulverized material. The initially wet particulate material is tangentially delivered by a carrier vapor flow to an upper portion of a generally vertical cylindrical separation drum. The lateral wall of the separation drum is provided with a plurality of flow guides for directing the vapor tangentially therein in the direction of particulate material flow. Positioned concentrically within the separation drum and along the longitudinal axis thereof is a water-cooled condensation cylinder which is provided with a plurality of collection plates, or fins, on the outer lateral surface thereof. The cooled collection fins are aligned counter to the flow of the pulverized material and high enthalpy vapor mixture to maximize water vapor condensation thereon. The condensed liquid which includes moisture removed from the pulverized material then flows downward along the outer surface of the coolant cylinder and is collected and removed. The particles travel in a shallow helix due to respective centrifugal and vertical acceleration forces applied thereto. The individual particles of the pulverized material are directed outwardly by the vortex flow where they contact the inner cylindrical surface of the separation drum and are then deposited at the bottom thereof for easy collection and removal. The pulverized material drying apparatus is particularly adapted for drying coal fines and facilitates the recovery of the pulverized coal.

  5. Drying of pulverized material with heated condensible vapor

    DOEpatents

    Carlson, L.W.

    1984-08-16

    Apparatus for drying pulverized material utilizes a high enthalpy condensable vapor such as steam for removing moisture from the individual particles of the pulverized material. The initially wet particulate material is tangentially delivered by a carrier vapor flow to an upper portion of a generally vertical cylindrical separation drum. The lateral wall of the separation drum is provided with a plurality of flow guides for directing the vapor tangentially therein in the direction of particulate material flow. Positioned concentrically within the separation drum and along the longitudinal axis thereof is a water-cooled condensation cylinder which is provided with a plurality of collection plates, or fines, on the outer lateral surface thereof. The cooled collection fines are aligned counter to the flow of the pulverized material and high enthalpy vapor mixture to maximize water vapor condensation thereon. The condensed liquid which includes moisture removed from the pulverized materials then flows downward along the outer surface of the coolant cylinder and is collected and removed. The particles travel in a shallow helix due to respective centrifugal and vertical acceleration forces applied thereto. The individual particles of the pulverized material are directed outwardly by the vortex flow where they contact the inner cylindrical surface of the separation drum and are then deposited at the bottom thereof for easy collection and removal. The pulverized material drying apparatus is particularly adapted for drying coal fines and facilitates the recovery of the pulverized coal. 2 figs.

  6. Estimation of heat load in waste tanks using average vapor space temperatures

    SciTech Connect

    Crowe, R.D.; Kummerer, M.; Postma, A.K.

    1993-12-01

    This report describes a method for estimating the total heat load in a high-level waste tank with passive ventilation. This method relates the total heat load in the tank to the vapor space temperature and the depth of waste in the tank. Q{sub total} = C{sub f} (T{sub vapor space {minus}} T{sub air}) where: C{sub f} = Conversion factor = (R{sub o}k{sub soil}{sup *}area)/(z{sub tank} {minus} z{sub surface}); R{sub o} = Ratio of total heat load to heat out the top of the tank (function of waste height); Area = cross sectional area of the tank; k{sub soil} = thermal conductivity of soil; (z{sub tank} {minus} z{sub surface}) = effective depth of soil covering the top of tank; and (T{sub vapor space} {minus} T{sub air}) = mean temperature difference between vapor space and the ambient air at the surface. Three terms -- depth, area and ratio -- can be developed from geometrical considerations. The temperature difference is measured for each individual tank. The remaining term, the thermal conductivity, is estimated from the time-dependent component of the temperature signals coming from the periodic oscillations in the vapor space temperatures. Finally, using this equation, the total heat load for each of the ferrocyanide Watch List tanks is estimated. This provides a consistent way to rank ferrocyanide tanks according to heat load.

  7. Vapor Flow Patterns During a Start-Up Transient in Heat Pipes

    NASA Technical Reports Server (NTRS)

    Issacci, F.; Ghoniem, N, M.; Catton, I.

    1996-01-01

    The vapor flow patterns in heat pipes are examined during the start-up transient phase. The vapor core is modelled as a channel flow using a two dimensional compressible flow model. A nonlinear filtering technique is used as a post process to eliminate the non-physical oscillations of the flow variables. For high-input heat flux, multiple shock reflections are observed in the evaporation region. The reflections cause a reverse flow in the evaporation and circulations in the adiabatic region. Furthermore, each shock reflection causes a significant increase in the local pressure and a large pressure drop along the heat pipe.

  8. Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, July 1--September 30, 1995

    SciTech Connect

    Suuberg, E.M.

    1995-12-31

    There is significant current interest in general area of coal pyrolysis, particularly because of the central role of pyrolysis in all thermally driven coal conversion processes-gasification, combustion, liquefaction, mild gasification, or thermal beneficiation. There remain several key data needs in these application areas. Among them is a need for more reliable correlation for prediction of vapor pressure of heavy, primary coal tars. The vapor pressure correlations that exist at present for coal tars are very crude and they are not considered reliable to even an order of magnitude when applied to tars. The present project seeks to address this important gap in the near term by direct measurement of vapor pressures of coal tar fractions, by application of well-established techniques and modifications thereof. The principal objectives of the program are to: (1) obtain data on the vapor pressures and heats of vaporization of tars from a range of ranks of coal, (2) develop correlations based on a minimum set of conveniently measurable characteristics of the tars, (3) develop equipment that would allow performing such measurements in a reliable, straightforward fashion. A significant amount of time has been devoted during this quarter to extending the work on measurements of vapor pressures of tars. For this purpose, cellulose tar and cellulose tar related compounds have been selected as model systems. Cellulose tar has a much narrower distribution of molecular weight than does coal tar, and it is much more homogeneous. Thus it is better to develop the methods to be used for coal tars on this simpler model system first.

  9. A thermodynamic view on latent heat transport, expansion work of water vapor and irreversible moist processes.

    NASA Astrophysics Data System (ADS)

    Pauluis, O.

    2001-05-01

    Three aspects of moist convection are discussed here: the latent heat transport from the Earth's surface to the regions where water vapor condenses, the expansion work performed by water vapor during its ascent, and the irreversible entropy production due to diffusion of water vapor and phase changes. A thermodynamic relationship between these three aspects of moist convection, referred here to as the entropy budget of the water substance, is derived. This relationship is similar to the entropy budget of an imperfect heat engine that produces less work than the corresponding Carnot cycle because of the irreversibility associated with diffusion of water vapor and irreversible phase changes. In addition to behaving as a heat engine, moist convection also acts as an atmospheric dehumidifier that removes water from the atmosphere through condensation and precipitation. In statistical equilibrium, this dehumidification is balanced by a continuous moistening of dry air, associated at the microphysical scales with diffusion of water vapor and irreversible phase changes. The irreversible entropy production due to these moist processes can thus be viewed as the irreversible counterpart to the atmospheric dehumidification. The entropy budget of the water substance thus indicates that there is a competition between how much the latent heat transport behaves as an atmospheric dehumidifier, and how much it behaves as a heat engine. Scaling arguments show that for conditions typical of the tropical atmosphere, the expansion work of water vapor accounts for about one third of the work that would be performed by a corresponding Carnot cycle. This implies that the latent heat transport acts more as an atmospheric dehumidifier than as a heat engine. This also implies that the amount of work performed by moist convection should be much weaker than what has been predicted by earlier theories that assume that convection behaves mostly as a perfect heat engine.

  10. Vapor Compression and Thermoelectric Heat Pumps for a Cascade Distillation Subsystem: Design and Experiment

    NASA Technical Reports Server (NTRS)

    Erickson, Lisa R.; Ungar, Eugene K.

    2012-01-01

    Humans on a spacecraft require significant amounts of water for drinking, food, hydration, and hygiene. Maximizing the reuse of wastewater while minimizing the use of consumables is critical for long duration space exploration. One of the more promising consumable-free methods of reclaiming wastewater is the distillation/condensation process used in the Cascade Distillation Subsystem (CDS). The CDS heats wastewater to the point of vaporization then condenses and cools the resulting water vapor. The CDS wastewater flow requires heating for evaporation and the product water flow requires cooling for condensation. Performing the heating and cooling processes separately would require two separate units, each of which would demand large amounts of electrical power. Mass, volume, and power efficiencies can be obtained by heating the wastewater and cooling the condensate in a single heat pump unit. The present work describes and compares two competing heat pump methodologies that meet the needs of the CDS: 1) a series of mini compressor vapor compression cycles and 2) a thermoelectric heat exchanger. In the paper, the CDS system level requirements are outlined, the designs of the two heat pumps are described in detail, and the results of heat pump analysis and performance tests are provided. The mass, volume, and power requirement for each heat pump option is compared and the advantages and disadvantages of each system are listed.

  11. Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, 1 January 1995--31 March 1995

    SciTech Connect

    Suuberg, E.M.; Oja, V.; Lilly, W.D.

    1995-08-01

    The vapor pressure correlations that exist at present for coal tars are very crude and they are not considered reliable to even an order of magnitude when applied to tars. Sophisticated general correlative approaches are slowly being developed, based upon group contribution methods, or based upon some key functional features of the molecules. These are as yet difficult to apply to coal tars. The detailed group contribution methods, in which fairly precise structural information is needed, do not lend themselves well for application to very complex, poorly characterized coal tars. The methods based upon more global types of characterizations have not yet dealt much with the question of oxygenated functional groups. In short, only very limited correlations exist, and these are not considered reliable to even an order of magnitude when applied to tars. The present project seeks to address this important gap in the near term by direct measurement of vapor pressures of coal tar fractions, by application of well-established techniques and modifications thereof. The principal objectives of the program are to: (1) obtain data on the vapor pressures and heats of vaporization of tars from a range of ranks of coal, (2) develop correlations based on a minimum set of conveniently measurable characteristics of the tars, (3) develop equipment that would allow performing such measurements in a reliable, straightforward fashion. A significant amount of time has been devoted during this quarter to testing the equipment for measurements by the Knudsen effusion method. The basic technique was described in the 9th Quarterly Report how the performance of the apparatus was checked by measuring, as a function of temperature, the vapor pressures of anthracene between 25 and 130{degrees}C, pyrene between 35 and 125{degrees}C, and coronene between 145 and 235{degrees}C.

  12. Vapor-Phase Stoichiometry and Heat Treatment of CdTe Starting Material for Physical Vapor Transport

    NASA Technical Reports Server (NTRS)

    Su, Ching-Hua; Sha, Yi-Gao; Lehoczky, S. L.; Liu, Hao-Chieh; Fang, Rei; Brebrick, R. F.

    1998-01-01

    Six batches of CdTe, having total amounts of material from 99 to 203 g and gross mole fraction of Te, X(sub Te), 0.499954-0.500138, were synthesized from pure Cd and Te elements. The vapor-phase stoichiometry of the assynthesized CdTe batches was determined from the partial pressure of Te2, P(sub Te2) using an optical absorption technique. The measured vapor compositions at 870 C were Te-rich for all of the batches with partial pressure ratios of Cd to Te2, P(sub Cd)/P(sub Te2), ranging from 0.00742 to 1.92. After the heat treatment of baking under dynamic vacuum at 870 C for 8 min, the vapor-phase compositions moved toward that of the congruent sublimation, i.e. P(sub Cd)/P(sub Te2) = 2.0, with the measured P(sub Cd)/P(sub Te2) varying from 1.84 to 3.47. The partial pressure measurements on one of the heat-treated samples also showed that the sample remained close to the congruent sublimation condition over the temperature range 800-880 C.

  13. An analysis of the vapor flow and the heat conduction through the liquid-wick and pipe wall in a heat pipe with single or multiple heat sources

    NASA Technical Reports Server (NTRS)

    Chen, Ming-Ming; Faghri, Amir

    1990-01-01

    A numerical analysis is presented for the overall performance of heat pipes with single or multiple heat sources. The analysis includes the heat conduction in the wall and liquid-wick regions as well as the compressibility effect of the vapor inside the heat pipe. The two-dimensional elliptic governing equations in conjunction with the thermodynamic equilibrium relation and appropriate boundary conditions are solved numerically. The solutions are in agreement with existing experimental data for the vapor and wall temperatures at both low and high operating temperatures.

  14. An analysis of the vapor flow and the heat conduction through the liquid-wick and pipe wall in a heat pipe with single or multiple heat sources

    NASA Technical Reports Server (NTRS)

    Chen, Ming-Ming; Faghri, Amir

    1990-01-01

    A numerical analysis is presented for the overall performance of heat pipes with single or multiple heat sources. The analysis includes the heat conduction in the wall and liquid-wick regions as well as the compressibility effect of the vapor inside the heat pipe. The two-dimensional elliptic governing equations in conjunction with the thermodynamic equilibrium relation and appropriate boundary conditions are solved numerically. The solutions are in agreement with existing experimental data for the vapor and wall temperatures at both low and high operating temperatures.

  15. A numerical analysis of the effects of conjugate heat transfer, vapor compressibility, and viscous dissipation in heat pipes

    NASA Technical Reports Server (NTRS)

    Faghri, Amir; Chen, Ming-Ming

    1989-01-01

    The effects of conjugate heat transfer, vapor compressibility, and viscous dissipation in heat pipes are discussed. The accuracy of the partially parabolic versus the elliptic presentation of the governing equations is also examined. The results show that the axial wall conduction has a tendency to make the temperature distribution more uniform for heat pipes with large ratios of pipe wall to effective liquid-wick thermal conductivity. The compressible and incompressible models show very close agreement for the total pressure drop, while the local pressure variations along the heat pipe are quite different for these two models when the radial Reynolds number at the interface is high.

  16. Dynamics of vaporization and dissociation during transient surface heating, with application to vacuum arcs

    SciTech Connect

    Benson, D.A.

    1981-02-01

    This report describes a model of vaporization and dissociation occurring as a result of intense heating over a localized area of a material surface. The balance of heat between the input power and losses due to vaporization, as well as radiation and conduction in the material, are considered. The model includes the effect of binary mass diffusion and changes of surface stoichiometry for multiple component materials. Effects of vapor recondensation are included. The model is then applied to the description of spot heating on a vacuum arc anode through the use of a simple power feedback model. Comparison of surface temperature measurements to model predictions are used to parametrically describe the arc behavior. Finally, extensive parametric analyses showing the effect of material property variations on the arc behavior are described.

  17. Heat Treatments of ZnSe Starting Materials for Physical Vapor Transport

    NASA Technical Reports Server (NTRS)

    Su, Ching-Hua; Palosz, W.; Feth, S.; Lehoczky, S. L.

    1998-01-01

    The effect of different heat treatments on stoichiometry and residual gas pressure in ZnSe physical vapor transport system was investigated. The dependence of the amount and composition of the residual gas on various heat treatment procedures is reported. Heat treatment of ZnSe starting materials by baking under the condition of dynamic vacuum to adjust its stoichiometry was performed and the effectiveness of the treatment was confirmed by the measurements of the partial pressure of Se2, P(sub Se2), in equilibrium with the heat treated samples. Optimum heat treatment procedures on the ZnSe starting material for the physical vapor transport process are discussed and verified experimentally.

  18. Heat Treatments of ZnSe Starting Materials for Physical Vapor Transport

    NASA Technical Reports Server (NTRS)

    Su, Ching-Hua; Palosz, W.; Feth, S.; Lehoczky, S. L.

    1997-01-01

    The effect of different heat treatments on stoichiometry and residual gas pressure in ZnSe physical vapor transport system was investigated. The dependence of the amount and composition of the residual gas on various heat treatment procedures is reported. Heat treatment of ZnSe starting materials by baking under the condition of dynamic vacuum to adjust its stoichiometry was performed and the effectiveness of the treatment was confirmed by the measurements of the partial pressure of Se2, P(sub Se2), in equilibrium with the heat treated samples. Optimum heat treatment procedures on the ZnSe starting material for the physical vapor transport process are discussed and verified experimentally.

  19. Heat Treatments of ZnSe Starting Materials for Physical Vapor Transport

    NASA Technical Reports Server (NTRS)

    Su, Ching-Hua; Palosz, W.; Feth, S.; Lehoczky, S. L.

    1997-01-01

    The effect of different heat treatments on stoichiometry and residual gas pressure in ZnSe physical vapor transport system was investigated. The dependence of the amount and composition of the residual gas on various heat treatment procedures is reported. Heat treatment of ZnSe starting materials by baking under the condition of dynamic vacuum to adjust its stoichiometry was performed and the effectiveness of the treatment was confirmed by the measurements of the partial pressure of Se2, P(sub Se2), in equilibrium with the heat treated samples. Optimum heat treatment procedures on the ZnSe starting material for the physical vapor transport process are discussed and verified experimentally.

  20. System for vaporizing carbon dioxide utilizing the heat by-product of the refrigeration system as a heat source

    SciTech Connect

    Shaw, H.L.

    1980-12-23

    The present invention is directed to a carbonation and refrigeration system wherein the heat of the refrigerant output side of the refrigeration compressor is utilized to vaporize liquid carbon dioxide into CO/sub 2/ gas which is introduced into a liquid product. The carbonation and refrigeration system successfully utilizes the heat of the refrigerant to vaporize the CO/sub 2/ liquid regardless of the cooling demand of the system caused by seasonal temperature variations. For example during the winter months when the cooling demand is as low as 10% of the cooling demand in the summer, the carbonation and refrigeration system operates effectively to vaporize the CO/sub 2/ liquid by means of a heat exchanger and a desuperheater which are connected in communication with the superheated vapor emerging from the output side of a refrigeration compressor. In addition, the carbonation and refrigeration system of the present invention cools more efficiently by extracting some of the heat from the condensed refrigerant entering the receiver of the refrigeration system. In this manner, the refrigeration compressor can operate more efficiently.

  1. Vapors-liquid phase separator. [infrared telescope heat sink

    NASA Technical Reports Server (NTRS)

    Frederking, T. H. K.; Brown, G. S.; Chuang, C.; Kamioka, Y.; Kim, Y. I.; Lee, J. M.; Yuan, S. W. K.

    1980-01-01

    The use of porous plugs, mostly with in the form of passive devices with constant area were considered as vapor-liquid phase separators for helium 2 storage vessels under reduced gravity. The incorporation of components with variable cross sectional area as a method of flow rate modification was also investigated. A particular device which uses a shutter-type system for area variation was designed and constructed. This system successfully permitted flor rate changes of up to plus or minus 60% from its mean value.

  2. An improved algorithm for the modeling of vapor flow in heat pipes

    NASA Technical Reports Server (NTRS)

    Tower, Leonard K.; Hainley, Donald C.

    1989-01-01

    A heat pipe vapor flow algorithm suitable for use in codes on microcomputers is presented. The incompressible heat pipe vapor flow studies of Busse are extended to incorporate compressibility effects. The Busse velocity profile factor is treated as a function of temperature and pressure. The assumption of a uniform saturated vapor temperature determined by the local pressure at each cross section of the pipe is not made. Instead, a mean vapor temperature, defined by an energy integral, is determined in the course of the solution in addition to the pressure, saturation temperature at the wall, and the Busse velocity profile factor. For alkali metal working fluids, local species equilibrium is assumed. Temperature and pressure profiles are presented for several cases involving sodium heat pipes. An example for a heat pipe with an adiabatic section and two evaporators in sequence illustrates the ability to handle axially varying heat input. A sonic limit plot for a short evaporator falls between curves for the Busse and Levy inviscid sonic limits.

  3. Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, October 1, 1995--December 31, 1995

    SciTech Connect

    Suuberg, E.M.; Oja, V.; Lilly, W.D.

    1996-06-01

    As the world continues to deplete its petroleum reserves, lower quality fossil fuels will play an increasingly important role in energy production. Heavy crude oil, coal liquids, and other heavy fossil fuels may be required to meet world energy needs. Heavy fossil fuels are generally higher in molecular weight, more aromatic, and contain more heteroatoms than higher quality petroleum. There will be an increasing need to deal with such low quality feedstocks, and therefore, an incentive to learn more about their properties. There is also significant current interest in the general area of coal pyrolysis, particularly with respect to comprehensive models of this complicated phenomenon. This interest derives from the central role of pyrolysis in all thermally driven coal conversion processes - gasification, combustion, liquefaction, mild gasification, or thermal beneficiation. There remain several key data needs in these application areas. Among them is a need for more reliable correlations for predicting vapor pressures of heavy, primary coal tars. Such information is important in design of all coal conversion processes, in which the volatility of tarry products is of major concern. This work presents results on vapor pressures and vaporization heat of polycyclic aromatic hydrocarbons and mixtures found in coal tar.

  4. Flows and Heat Exchange in a Geothermal Bed in the Process of Extraction of a Vapor-Water Mixture from It

    NASA Astrophysics Data System (ADS)

    Ramazanov, M. M.; Alkhasova, D. A.; Abasov, G. M.

    2017-05-01

    With the use of the finite-difference method, a nonstationary nonlinear problem on the heat and mass transfer in a geothermal bed in the process of extraction of a vapor-water mixture from it was solved numerically with regard for the heat exchange between the bed and the surrounding rocks. The results obtained were analyzed and compared with the results of earlier investigations. It was established that the heat exchange between the bed and its roof and bottom influences the heat and mass transfer in the neighborhood of a producing well in it. It is shown that this heat exchange increases somewhat the pressure (temperature) of the phase transition of the heat-transfer medium and changes its saturation with water. At the stage of stationary heat and mass transfer in the bed, this change leads to a decrease in the water saturation of the heat-transfer medium, i.e., to an additional evaporation of water from it. However, at the stage of substantially nonstationary heat and mass transfer in the bed, the pattern is more complex: within certain time intervals, the heat exchange in separate regions of the bed decreases the content of vapor in the heat-transfer medium (increases its saturation with water). Moreover, in both the cases of absence and presence of heat exchange between the bed and the surrounding rocks, the distributions of the water saturation of the heat-transfer medium in the bed executes damped oscillations and, in so doing, approaches the stationary state.

  5. Macroscopic modeling for heat and water vapor transfer in dry snow by homogenization.

    PubMed

    Calonne, Neige; Geindreau, Christian; Flin, Frédéric

    2014-11-26

    Dry snow metamorphism, involved in several topics related to cryospheric sciences, is mainly linked to heat and water vapor transfers through snow including sublimation and deposition at the ice-pore interface. In this paper, the macroscopic equivalent modeling of heat and water vapor transfers through a snow layer was derived from the physics at the pore scale using the homogenization of multiple scale expansions. The microscopic phenomena under consideration are heat conduction, vapor diffusion, sublimation, and deposition. The obtained macroscopic equivalent model is described by two coupled transient diffusion equations including a source term arising from phase change at the pore scale. By dimensional analysis, it was shown that the influence of such source terms on the overall transfers can generally not be neglected, except typically under small temperature gradients. The precision and the robustness of the proposed macroscopic modeling were illustrated through 2D numerical simulations. Finally, the effective vapor diffusion tensor arising in the macroscopic modeling was computed on 3D images of snow. The self-consistent formula offers a good estimate of the effective diffusion coefficient with respect to the snow density, within an average relative error of 10%. Our results confirm recent work that the effective vapor diffusion is not enhanced in snow.

  6. Multicharged iron ions produced by using induction heating vapor source.

    PubMed

    Kato, Yushi; Kubo, Takashi; Muramatsu, Masayuki; Tanaka, Kiyokatsu; Kitagawa, Atsushi; Yoshida, Yoshikazu; Asaji, Toyohisa; Sato, Fuminobu; Iida, Toshiyuki

    2008-02-01

    Multiply charged Fe ions are produced from solid pure material in an electron cyclotron resonance (ECR) ion source. We develop an evaporator by using induction heating with an induction coil which is made of bare molybdenum wire partially covered by ceramic beads in vacuum and surrounding and heating directly the pure Fe rod. Heated material has no contact with insulators, so that outgas is minimized. The evaporator is installed around the mirror end plate outside of the ECR plasma with its hole grazing the ECR zone. Helium or argon gas is usually chosen for supporting gas. The multicharged Fe ions up to Fe(13+) are extracted from the opposite side of mirror and against the evaporator, and then multicharged Fe ion beam is formed. We compare production of multicharged iron ions by using this new source with our previous methods.

  7. Flat-plate /vapor-chamber/ heat pipes

    NASA Technical Reports Server (NTRS)

    Fleischman, G. L.; Marcus, B. D.; Mcintosh, R.; Ollendorf, S.

    1975-01-01

    This paper discusses the design, fabrication and testing of heat pipes constructed in the form of flat-plate panels. The test panels were constructed of copper with methyl alcohol as the working fluid. Capillary grooves etched on the internal surfaces provided evaporation and condensation heat-transfer coefficients on the order of 1600 Btu/hr-sq ft-deg F. Two panels were launched on board a sounding rocket; the payload reached an altitude of 140 miles, and zero gravity was achieved for almost six minutes. The panel with working fluid inside demonstrated a heat input flux of 2.5 watts/sq cm, with only a 3 to 5 C temperature difference throughout the entire panel.

  8. Buoyancy-Driven Heat Transfer During Application of a Thermal Gradient for the Study of Vapor Deposition at Low Pressure Using and Ideal Gas

    NASA Technical Reports Server (NTRS)

    Frazier, D. O.; Hung, R. J.; Paley, M. S.; Penn, B. G.; Long, Y. T.

    1996-01-01

    A mathematical model has been developed to determine heat transfer during vapor deposition of source materials under a variety of orientations relative to gravitational accelerations. The model demonstrates that convection can occur at total pressures as low as 10-2 mm Hg. Through numerical computation, using physical material parameters of air, a series of time steps demonstrates the development of flow and temperature profiles during the course of vapor deposition. These computations show that in unit gravity vapor deposition occurs by transport through a fairly complicated circulating flow pattern when applying heat to the bottom of the vessel with parallel orientation with respect to the gravity vector. The model material parameters for air predict the effect of kinematic viscosity to be of the same order as thermal diffusivity, which is the case for Prandtl number approx. 1 fluids. Qualitative agreement between experiment and the model indicates that 6-(2-methyl-4-nitroanilino)-2,4-hexadiyn-l-ol (DAMNA) at these pressures indeed approximates an ideal gas at the experiment temperatures, and may validate the use of air physical constants. It is apparent that complicated nonuniform temperature distribution in the vapor could dramatically affect the homogeneity, orientation, and quality of deposited films. The experimental test i's a qualitative comparison of film thickness using ultraviolet-visible spectroscopy on films generated in appropriately oriented vapor deposition cells. In the case where heating of the reaction vessel occurs from the top, deposition of vapor does not normally occur by convection due to a stable stratified medium. When vapor deposition occurs in vessels heated at the bottom, but oriented relative to the gravity vector between these two extremes, horizontal thermal gradients induce a complex flow pattern. In the plane parallel to the tilt axis, the flow pattern is symmetrical and opposite in direction from that where the vessel is

  9. Liquid-Vapor Flow Regime Transitions for Spacecraft Heat Transfer Loops

    DTIC Science & Technology

    1988-12-01

    heavenly bodies, in spite of their astonishing distances, than in the investigations of the movement of flowing water before our very eyes" Galileo ... Galilei 1564-1642 Motivation to Study MicroQravity Flow Reuimes The study of microgravity vapor-liquid flow regimes is motivated by the benefits of heat

  10. What Is the Boiling Point and Heat of Vaporization of Sulfuric Acid?

    ERIC Educational Resources Information Center

    Myers, R. Thomas

    1983-01-01

    Discusses the values presented in various handbooks for the boiling point and heat of vaporization of sulfuric acid, noting discrepencies. Analyzes various approaches to data presentation, discussing the data on sulfuric acid in light of the Trouton constant. Points out the need for a more critical use of tables. (JM)

  11. What Is the Boiling Point and Heat of Vaporization of Sulfuric Acid?

    ERIC Educational Resources Information Center

    Myers, R. Thomas

    1983-01-01

    Discusses the values presented in various handbooks for the boiling point and heat of vaporization of sulfuric acid, noting discrepencies. Analyzes various approaches to data presentation, discussing the data on sulfuric acid in light of the Trouton constant. Points out the need for a more critical use of tables. (JM)

  12. Experimental Study of Heat Transfer Induced by a Single Vapor Bubble Growth: Influence of Liquid Subcooling

    NASA Astrophysics Data System (ADS)

    Barthes, Magali; Reynard, Christelle; Santini, Robert; Tadrist, Lounès

    2004-02-01

    Heat exchanges during boiling are of high interest for cooling systems. The objective of this work is to investigate heat transfer around a single vapor bubble, the influence of the liquid subcooling and of the heat flux applied on the nucleation surface. Experiments on subcooled pool boiling at atmospheric pressure for a single vapor bubble were conducted and the obtained results are presented. The bubble was created on a downward facing heating element. Generation of the single bubble was achieved on an artificial cavity; the indentation was made on a fluxmeter (Captec Entreprise®). FC-72 was used as the test liquid, and its subcooling was maintained to 8 and 14K. Two heating powers were applied on the nucleation surface, and maintained constant during each experiment. Evolutions of bubble size and shape, as a function of wall superheat and liquid subcooling, were followed and studied using a 25 fps video camera. The effect of heating power and subcooling on growth periods were found to be significant. Total heat fluxes during bubble growth were measured using the fluxmeter, for different levels of subcooling and heating powers. Image and data processing has enabled us to show up influence of bubble growth on heat transfer and to determine nucleation periodicity. These preliminary results are discussed.

  13. Performance evaluation of a vapor compression heat pump cycle using binary zeotropic refrigerant mixtures

    SciTech Connect

    Koyama, Shigeru; Yara, Tomoyasu

    1999-07-01

    The HCFC refrigerants such as R22 have been used widely as working fluids in refrigeration and air-conditioning systems until now. These refrigerants, however, should be phased out early in the next century to prevent the depletion of the ozone layer. In this situation, binary and/or ternary mixtures composed of HFC and/or natural refrigerants have attracted a great deal of attention due to the following possibilities: (1) to improve the coefficient of performance, COP, by utilizing the temperature glide during phase change processes; (2) to keep the system in more suitable condition for given temperature levels of heat source and heat sink by selecting the combination and composition of refrigerants, etc. From this point of view, in the present study, the performance prediction of a vapor compression heat pump cycle using binary zeotropic refrigerant mixtures is carried out to clarify the effects of the combination of refrigerants, the composition of refrigerants and the size of heat exchangers on COP. In the prediction calculation, a vapor compression heat pump cycle, which consists of a compressor, a vertical plate-fin condenser, an expansion valve, a liquid-vapor separator and a vertical plate-fin evaporator is treated, and the following assumptions are employed: (1) the compression process is isentropic, (2) the expansion process is isenthalpic, (3) the refrigerant is a saturated liquid at the condenser outlet and a superheated vapor at the evaporator outlet, (4) the pressure drop in the condenser is negligible, while that in the evaporator is considered, (5) the local heat transfer characteristics in heat exchangers are considered. The prediction calculation is done for the binary zeotropic refrigerant mixtures of HFC134a/HCFC123 on condition that the heat source water temperature at the condenser outlet, the heat sink water temperature at the evaporator inlet, the water temperature change through condenser and evaporator, the heat load of condenser, the

  14. Heat and Mass Diffusions in the Absorption of Water Vapor by Aqueous Solution of Lithium Bromide

    NASA Astrophysics Data System (ADS)

    Kashiwagi, Takao; Kurosaki, Yasuo; Nikai, Isao

    The recent development of absorption-type heat pump is highly essential from the viewpoint of extracting the effective energy from waste heat or solar energy. To increase the efficiency of energy conversion, it is important to improve the performance of absorbers. The objective of this paper is to obtain an increased understanding of the fine mechanisms of vapor absorption. A system combining holographic interferometry wity thermometry is adopted to observe the progress of one-dimensional water vapor absorption by aqueous solution of lithium bromide (LiBr) and also to measure the unsteady temperature and concentration distributions in the absorption process. The experiments are carried out under the condition that the solution surface is exposed to the saturated water vapor at reduced pressure, and the effects of LiBr mass concentration on absorption mechanism are examined in the concentration range 20-60 mass%. The interference fringes are analyzed to distinguish between the layers of heat conduction and mass diffusion. The temperature and concentration distributions thus determined experimentally are compared with numerical solutions obtained by the equations for unsteady heat conduction and mass diffusion taking into consideration the effect of heat by dilution, to give reasonable values of mass diffusivity hitherto remaining unknown. Especially in the range of 40-60 mass%, the mass diffusivity decreases extremely with the increase of mass concentration of LiBr and it falls down to 0.7-0.8×10-9 m2/s in case of 60 mass% solution.

  15. The influence of convective heat transfer on flow stability in rotating disk chemical vapor deposition reactors

    SciTech Connect

    Winters, W.S.; Evans, G.H.; Grief, R.

    1997-06-01

    Flow and heat transfer of NH{sub 3} and He were studied in a rotating disk system with applications to chemical vapor deposition reactors. Flow field and disk heat flux were obtained over a range of operating conditions. Comparisons of disk convective heat transfer were made to infinite rotating disk results to appraise uniformity of transport to the disk. Important operating variables include disk spin rate, disk and enclosure temperatures, flow rate, composition, pressure, and gas mixture temperature at the reactor inlet. These variables were studied over ranges of the spin Reynolds number, Re{omega}; disk mixed convection parameter, MCP{sub w}; and wall mixed convection parameter, MCP{sub w}. Results obtained for NH{sub 3} show that increasing Re{omega} from 314.5 to 3145 increases the uniformity of rotating disk heat flux and results in thinner thermal boundary layers at the disk surface. At Re{omega}=314.5, increasing MCP{sub d} to 15 leads to significant departure from the infinite disk result with nonuniform disk heat fluxes and recirculating flow patterns; flow becomes increasingly complex at larger values of MCP{sub d}. At Re{omega} of 3145, results are closer to the infinite disk for MCP{sub d} up to 15. For large negative (hot walls) and positive (cold walls) values of MCP{sub w}, flow recirculates and there is significant deviation from the infinite disk result; nonuniformities occur at both values of Re{omega}. The influence of MCP{sub w} on flow stability is increased at larger MCP{sub d} and lower Re{omega}. To determine the influence of viscosity and thermal conductivity variation with temperature, calculations were made with He and NH{sub 3}; He transport property variation is low relative to NH{sub 3}. Results show that the flow of NH{sub 3} is less stable than that of He as MCP{sub d} is increased for MCP{sub w}=0 and Re{omega}=314.5. 16 refs., 15 figs., 1 tab.

  16. Computational prediction of standard gas, liquid, and solid-phase heats of formation and heats of vaporization and sublimation

    NASA Astrophysics Data System (ADS)

    Politzer, Peter; Ma, Yuguang; Lane, Pat; Concha, Monica C.

    We present a B3PW91/6-31G** computational procedure for predicting standard gas phase heats of formation at 298.15 K by finding ΔH for the process whereby the molecule is produced from its elements and then adding empirical atomic correction terms. Heats of vaporization and sublimation are estimated on the basis of the calculated electrostatic potential on the molecular surface. These results permit prediction of the standard liquid and solid-phase heats of formation. In comparison with experimental data, the average absolute deviations are as follows: for the heats of formation, gas phase, 2.6 kcal/mol; liquid phase, 2.4 kcal/mol; solid phase, 3.8 kcal/mol; for the heats of vaporization, 2.0 kcal/mol; and for the heats of sublimation, 2.8 kcal/mol. Computed values of these properties are given for a number of compounds for which they are not available experimentally.

  17. Rapid Vaporization and Heating of Two Parallel Fuel Droplet Streams

    DTIC Science & Technology

    1986-04-01

    injected in a hot gas. With the assumption of a constant relative ’velocity between the gas and liquid phases (inviscid approximation), a system of partial...Disftimotr - Mited.1912MATTHEw, •-•.- 094f~ Techr.1c,4, ’nforffgbI DWI=iI Presented at the 1986 Spring Technical Meeting Canadian and Western States Sections...The Combustion Institute Banff , Alberta, Canada April 27-3u, 1986 $ , I• 0 ~ ~ ~ !7 Abstract An analysis is presented of the mechanism ,• heat transfer

  18. Vaporization heat transfer of dielectric liquids on enhanced surfaces covered with screen wicks

    NASA Technical Reports Server (NTRS)

    Gu, C. B.; Chow, L. C.; Pais, M. R.; Baker, K.

    1993-01-01

    Experiments were conducted to investigate the vaporization heat transfer characteristics for the dielectric liquid FC-72 on several wicking surfaces which may be used in flat-plate heat pipes. The wicking materials studied included microstructure enhanced surfaces and coarse surfaces covered with screen meshes. Experimental data for q versus deltaT curves and critical heat fluxes were obtained for the two different operating conditions of a heat pipe, evaporation, and shallow pool boiling. When the liquid level was above the heated surface, the height of the liquid level above the surface was varied from 0 to 10 mm. When the liquid level was below the heated surface, the distance from the liquid level to the edge of the surface was adjusted from 0 to 15 mm. Experimental results revealed that for shallow pool boiling when the heated surface was covered with a wire screen mesh, the heat transfer coefficient increased at lower heat fluxes but the critical heat flux (CHF) decreased for all the surfaces tested. In the case of evaporation, both CHF and the heat transfer coefficient increased as the microstructure surfaces were covered with screen meshes.

  19. Energy balance between vaporization and heating in the absorption of CO2 laser radiation by water

    NASA Astrophysics Data System (ADS)

    Mueller, Robert E.; Yam, Henry; Duley, Walter W.

    1997-03-01

    The use of lasers in industrial and medical procedures continues to increase. A fundamental question in many laser- material interactions is how is the incident laser power transferred to the target material, and how is the power distributed among the phases (solid, liquid, vapor) of the material. This paper describes the results of a fundamental calorimetry experiment to determine the fraction of incident carbon-dioxide laser energy which is used to vaporize water from a target volume, and the fraction of power used to simply heat the remaining liquid. The experiment was performed over a range of incident laser powers from 60 to 300 W. Over most of the range of incident power, the fraction used to vaporize water is 30 to 35 percent. This fraction increases at the lowest powers.

  20. FUNDAMENTAL AREAS OF PHENOMENOLOGY (INCLUDING APPLICATIONS): Numerical Simulation of Vapor Bubble Growth and Heat Transfer in a Thin Liquid Film

    NASA Astrophysics Data System (ADS)

    Tao, Yu-Jia; Huai, Xiu-Lan; Li, Zhi-Gang

    2009-07-01

    A mathematical model is developed to investigate the dynamics of vapor bubble growth in a thin liquid film, movement of the interface between two fluids and the surface heat transfer characteristics. The model takes into account the effects of phase change between the vapor and liquid, gravity, surface tension and viscosity. The details of the multiphase now and heat transfer are discussed for two cases: (1) when a water micro-droplet impacts a thin liquid film with a vapor bubble growing and (2) when the vapor bubble grows and merges with the vapor layer above the liquid film without the droplet impacting. The development trend of the interface between the vapor and liquid is coincident qualitatively with the available literature, mostly at the first stage. We also provide an important method to better understand the mechanism of nucleate spray cooling.

  1. Heat standards calibration in the DOE complex

    SciTech Connect

    Carillo, L.A.; Rudy, C.R.; Long, S.M.; McDaniel, J.; Rodenburg, W.W.

    1997-11-01

    As part of the Department of Energy (DOE) Non-nuclear Reconfiguration Program, the Office of Safeguards and Security Calorimetry Development Program has transferred from EG and G Mound Applied Technologies to the Los Alamos National Laboratory. An important function of this program is the calibration and certification of {sup 238}Pu heat standards, which are used to assure accountability of plutonium and tritium throughout the complex. To facilitate relatively uninterrupted calibration service, two calorimeters have been installed in the Los Alamos Plutonium Facility (TA-55). These calorimeters are capable of highly accurate measurements of heat standards with power ranging from 0.01 to 20 W. In addition, two new EG and G Mound Applied Technologies calibration calorimeters with a robot handling system have been installed in the Nuclear Safeguards Laboratories at Los Alamos National Laboratory. These calorimeters are located in a specially constructed laboratory that is controlled for temperature and humidity to achieve low uncertainty in the measurements. Because transportation of aging heat standards between sites within the DOE complex has become increasingly difficult, the authors are looking into several approaches to this problem. Repackaging of all heat standards to comply with Department of Transportation and American Nuclear Standards Institute requirements is a long-term goal.

  2. Generalized computer algorithms for enthalpy, entropy and specific heat of superheated vapors

    NASA Astrophysics Data System (ADS)

    Cowden, Michael W.; Scaringe, Robert P.; Gebre-Amlak, Yonas D.

    This paper presents an innovative technique for the development of enthalpy, entropy, and specific heat correlations in the superheated vapor region. The method results in a prediction error of less than 5 percent and requires the storage of 39 constants for each fluid. These correlations are obtained by using the Beattie-Bridgeman equation of state and a least-squares regression for the coefficients involved.

  3. Vapor Jet Ejector Used to Generate Free Waste Heat Driven Cooling in Military Environmental Cooling Units

    DTIC Science & Technology

    2012-07-01

    vap erant vapor is or by a J-tub essure side of using similar pressure incre ump in order o the diesel-e per heat excha recovered at to the exhaus...top of the a tering the com at exchanger. g of the conve id flow. A nit essure pulsati tor where the ed in the cool erature level. ger where wa

  4. Heat diffusion: Thermodynamic depth complexity of networks

    NASA Astrophysics Data System (ADS)

    Escolano, Francisco; Hancock, Edwin R.; Lozano, Miguel A.

    2012-03-01

    In this paper we use the Birkhoff-von Neumann decomposition of the diffusion kernel to compute a polytopal measure of graph complexity. We decompose the diffusion kernel into a series of weighted Birkhoff combinations and compute the entropy associated with the weighting proportions (polytopal complexity). The maximum entropy Birkhoff combination can be expressed in terms of matrix permanents. This allows us to introduce a phase-transition principle that links our definition of polytopal complexity to the heat flowing through the network at a given diffusion time. The result is an efficiently computed complexity measure, which we refer to as flow complexity. Moreover, the flow complexity measure allows us to analyze graphs and networks in terms of the thermodynamic depth. We compare our method with three alternative methods described in the literature (Estrada's heterogeneity index, the Laplacian energy, and the von Neumann entropy). Our study is based on 217 protein-protein interaction (PPI) networks including histidine kinases from several species of bacteria. We find a correlation between structural complexity and phylogeny (more evolved species have statistically more complex PPIs). Although our methods outperform the alternatives, we find similarities with Estrada's heterogeneity index in terms of network size independence and predictive power.

  5. Heat treatment's effects on hydroxyapatite powders in water vapor and air atmosphere

    NASA Astrophysics Data System (ADS)

    Karabulut, A.; Baştan, F. E.; Erdoǧan, G.; Üstel, F.

    2015-03-01

    Hydroxyapatite (HA; Ca10(PO4)6(OH)2) is the main chemical constituent of bone tissue (~70%) as well as HA which is a calcium phosphate based ceramic material forms inorganic tissue of bone and tooth as hard tissues is used in production of prosthesis for synthetic bone, fractured and broken bone restoration, coating of metallic biomaterials and dental applications because of its bio compatibility. It is known that Hydroxyapatite decomposes with high heat energy after heat treatment. Therefore hydroxyapatite powders that heated in water vapor will less decomposed phases and lower amorphous phase content than in air atmosphere. In this study high purity hydroxyapatite powders were heat treated with open atmosphere furnace and water vapor atmosphere with 900, 1000, 1200 °C. Morphology of same powder size used in this process by SEM analyzed. Chemical structures of synthesized coatings have been examined by XRD. The determination of particle size and morphological structure of has been characterized by Particle Sizer, and SEM analysis, respectively. Weight change of sample was recorded by thermogravimetric analysis (TGA) during heating and cooling.

  6. Pure Material Vapor Source by Induction Heating Evaporator for an Electron Cyclotron Resonance Ion Source

    SciTech Connect

    Matsui, Y.; Watanabe, T.; Satani, T.; Sato, F.; Kato, Y.; Iida, T.; Muramatsu, M.; Kitagawa, A.; Tanaka, K.; Yoshida, Y.

    2008-11-03

    Multiply charged iron ions are produced from solid pure material in an electron cyclotron resonance (ECR) ion source. We develop an evaporator by using induction heating with the induction coil which is made from bare molybdenum wire and surrounding the pure iron rod. We optimize the shape of induction heating coil and operation of rf power supply. We conduct experiment to investigate reproducibility and stability in the operation and heating efficiency. Induction heating evaporator produces pure material vapor, because materials directly heated by eddy currents have non-contact with insulated materials which are impurity gas sources. The power and the frequency of the induction currents range from 100 to 900 W and from 48 to 23 kHz, respectively. The working pressure is about 10{sup -4} to 10{sup -3} Pa. We measure temperature of iron rod and film deposition rate by depositing iron vapor to crystal oscillator. We confirm stability and reproducibility of evaporator enough to conduct experiment in ECR ion source. We can obtain required temperature of iron under maximum power of power supply. We are aiming the evaporator higher melting point material than iron.

  7. Development of a Parching Machine Using Super-Heated Vapor or Super-Heated High-Moisture Atmosphere

    NASA Astrophysics Data System (ADS)

    Sato, Shoichi; Shinsho, Seiji; Iriki, Hiroyuki; Asai, Junya; Suganuma, Hirofumi; Shibata, Tsutomu

    We developed a new parching machine with super-heated vapor or super-heated highmoisture atmosphere as a heat medium, and investigated the influence exerted on the characteristics of manufactured tea and crude tea quality. (1)We developed machine specifications that improved throughput and allowed us to control stable quality compared with the conventional kamairicha parching machine. (2)The new parching machine could not only manufacture like kamairicha but also achieve various degrees of steaming of products like green tea or heavily steamed sencha. (3)The new parching machine could not only deactivate enzymes but dry leaves. (4)The influence of throughput was great with respect to the grade of pan-parched flavour, which meant that there was a contact opportunity for tea leaves and the surface of machine's wall. (5)Unpleasant smells such as that produced in a summer crop of tea were reduced by the new parching machine.

  8. Development of a new laser heating system for thin film growth by chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Fujimoto, Eiji; Sumiya, Masatomo; Ohnishi, Tsuyoshi; Lippmaa, Mikk; Takeguchi, Masaki; Koinuma, Hideomi; Matsumoto, Yuji

    2012-09-01

    We have developed a new laser heating system for thin film growth by chemical vapor deposition (CVD). A collimated beam from a high-power continuous-wave 808 nm semiconductor laser was directly introduced into a CVD growth chamber without an optical fiber. The light path of the heating laser inside the chamber was isolated mechanically from the growth area by bellows to protect the optics from film coating. Three types of heat absorbers, (10 × 10 × 2 mm3) consisting of SiC, Ni/NiOx, or pyrolytic graphite covered with pyrolytic BN (PG/PBN), located at the backside of the substrate, were tested for heating performance. It was confirmed that the substrate temperature could reach higher than 1500 °C in vacuum when a PG/PBN absorber was used. A wide-range temperature response between 400 °C and 1000 °C was achieved at high heating and cooling rates. Although the thermal energy loss increased in a H2 gas ambient due to the higher thermal conductivity, temperatures up to 1000°C were achieved even in 200 Torr H2. We have demonstrated the capabilities of this laser heating system by growing ZnO films by metalorganic chemical vapor deposition. The growth mode of ZnO films was changed from columnar to lateral growth by repeated temperature modulation in this laser heating system, and consequently atomically smooth epitaxial ZnO films were successfully grown on an a-plane sapphire substrate.

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

    PubMed

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

    2015-01-01

    Modular and compact adsorption heat pumps (AHPs) promise an energy-efficient alternative to conventional vapor compression based heating, ventilation and air conditioning systems. A key element in the advancement of AHPs is the development of adsorbents with high uptake capacity, fast intracrystalline diffusivity and durable hydrothermal stability. Herein, the ion exchange of NaY zeolites with ingoing Mg(2+) ions is systematically studied to maximize the ion exchange degree (IED) for improved sorption performance. It is found that beyond an ion exchange threshold of 64.1%, deeper ion exchange does not benefit water uptake capacity or characteristic adsorption energy, but does enhance the vapor diffusivity. In addition to using water as an adsorbate, the uptake properties of Mg,Na-Y zeolites were investigated using 20 wt.% MeOH aqueous solution as a novel anti-freeze adsorbate, revealing that the MeOH additive has an insignificant influence on the overall sorption performance. We also demonstrated that the labscale synthetic scalability is robust, and that the tailored zeolites scarcely suffer from hydrothermal stability even after successive 108-fold adsorption/desorption cycles. The samples were analyzed using N2 sorption, (27)Al/(29)Si MAS NMR spectroscopy, ICP-AES, dynamic vapor sorption, SEM, Fick's 2(nd) law and D-R equation regressions. Among these, close examination of sorption isotherms for H2O and N2 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.

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

    SciTech Connect

    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.

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

    PubMed Central

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

    2014-01-01

    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 labscale synthetic scalability is robust, and that the tailored zeolites scarcely suffer from hydrothermal stability even after successive 108-fold adsorption/desorption cycles. The samples were analyzed using N2 sorption, 27Al/29Si 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 N2 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. PMID:25395877

  12. Vapor shield protection of plasma facing components under incident high heat flux

    NASA Astrophysics Data System (ADS)

    Gilligan, J.; Bourham, M.; Hankins, O.; Eddy, W.; Hurley, J.; Black, D.

    1992-12-01

    Disruption damage to plasma facing components has been found to be a limiting design constraint in ITER and other large fusion devices. A growing data base is confirming the role of the vapor shield in protecting ablated surfaces under disruption-like conditions, which would imply longer lifetimes for plasma facing components. We present new results for exposure of various material surfaces to high heat fluxes up to 70 GW/m 2 over 100 μs (7 MJ/m 2) in the SIRENS high heat flux test facility. Tested materials are graphite grades, pyrolytic graphite, refractory metals and alloys, refractory coatings on copper substrates, boron nitride and preliminary results of diamond coating on silicon substrates. An empirical scaling law of the energy transmission factor through the vapor shield has been obtained. The application of a strong external magnetic field, to reduce turbulent energy transport in the vapor shield boundary, is shown to decrease f by as much as 35% for fields of 8 T.

  13. Equilibrium and heat of adsorption for organic vapors and activated carbons

    SciTech Connect

    David Ramirez; Shaoying Qi; Mark J. Rood; K. James Hay

    2005-08-01

    Determination of the adsorption properties of novel activated carbons is important to develop new air quality control technologies that can solve air quality problems in a more environmentally sustainable manner. Equilibrium adsorption capacities and heats of adsorption are important parameters for process analysis and design. Experimental adsorption isotherms were thus obtained for relevant organic vapors with activated carbon fiber cloth (ACFC) and coal-derived activated carbon adsorbents (CDAC). The Dubinin-Astakhov (DA) equation was used to describe the adsorption isotherms. The DA parameters were analytically and experimentally shown to be temperature independent. The resulting DA equations were used with the Clausius-Clapeyron equation to analytically determine the isosteric heat of adsorption ({Delta}H{sub s}) of the adsorbate-adsorbent systems studied here. ACFC showed higher adsorption capacities for organic vapors than CDAC. {Delta}H{sub s} values for the adsorbates were independent of the temperature for the conditions evaluated. {Delta}H{sub s} values for acetone and benzene obtained in this study are comparable with values reported in the literature. This is the first time that {Delta}H{sub s} values for organic vapors and these adsorbents are evaluated with an expression based on the Polanyi adsorption potential and the Clausius-Clapeyron equation. 28 refs., 5 figs., 5 tabs., 3 appends.

  14. Heat transfer in horizontal two-phase helium II and vapor

    NASA Astrophysics Data System (ADS)

    Panek, John Stanley

    This thesis examines heat transport in horizontal two- phase helium II and vapor in a 2 meter long test section with cross section 3 mm wide and 65 mm tall. Liquid and vapor temperatures are measured at eight locations, six along the channel and two in the boundary reservoirs. The six measurements along the channel are at three equally spaced axial locations, each with one thermometer in the liquid and one in the vapor. Boundary temperatures selected are 1.4, 1.8, and 2.0 K and with up to 20 mK temperature difference across the channel. The liquid level at the cold end of the channel is set at 60, 50, or 40 mm, and the warm end level is lower due to differences in saturated pressure. The effect of bellows pumps forcing up to 0.66 g/s of liquid with or against the temperature gradient is also measured. A numerical model is constructed which solves the main governing nonlinear ordinary differential equations for energy transport and compared to some of the experimental results. Agreement between the model and experiment is good if one assumes a certain reasonable value for parasitic heat load to the experiment. A second model is constructed to describe isothermal two- phase forced flow, which is similar to open channel flow. The height change at each end of the reservoir is a function of liquid flow rate, and the measured friction factors agree well with a classical correlation.

  15. Complex Heat Exchangers for Improved Performance

    NASA Astrophysics Data System (ADS)

    Bran, Gabriela Alejandra

    After a detailed literature review, it was determined that there was a need for a more comprehensive study on the transient behavior of heat exchangers. Computational power was not readily available when most of the work on transient heat exchangers was done (1956 - 1986), so most of these solutions have restrictions, or very specific assumptions. More recently, authors have obtained numerical solutions for more general problems (2003 - 2013), but they have investigated very specific conditions, and cases. For a more complex heat exchanger (i.e. with heat generation), the transient solutions from literature are no longer valid. There was a need to develop a numerical model that relaxes the restrictions of current solutions to explore conditions that have not been explored. A one dimensional transient heat exchanger model was developed. There are no restrictions on the fluids and wall conditions. The model is able to obtain a numerical solution for a wide range of fluid properties and mass flow rates. Another innovative characteristic of the numerical model is that the boundary and initial conditions are not limited to constant values. The boundary conditions can be a function of time (i.e. sinusoidal signal), and the initial conditions can be a function of position. Four different cases were explored in this work. In the first case, the start-up of a system was investigated where the whole system is assumed to be at the same temperature. In the second case, the new steady state in case one gets disrupted by a smaller inlet temperature step change. In the third case, the new steady state in case one gets disrupted by a step change in one of the mass flow rates. The response of these three cases show that there are different transient behaviors, and they depend on the conditions imposed on the system. The fourth case is a system that has a sinusoidal time varying inlet temperature for one of the flows. The results show that the sinusoidal behavior at the inlet

  16. Specific heat capacity and density of multi-walled boron nitride nanotubes by chemical vapor deposition

    NASA Astrophysics Data System (ADS)

    Zhi, Chunyi; Bando, Yoshio; Tang, Chengchun; Golberg, Dmitri

    2011-01-01

    We report on the basic physical quantities of boron nitride nanotubes (BNNTs), namely specific heat capacity and density, which have not been measured to date. A series of differential scanning calorimetry experiments were performed, and specific heat capacity was calculated for multi-walled BNNTs synthesized by chemical vapor deposition using boron and metal oxide as precursor. Very close specific heat capacity values were revealed for BNNTs and a BN powder of hexagonal (h-BN) phase. Densities of BNNTs were measured through density analyses of their epoxy composites. Our work is important as far as bulk properties of large amounts of BNNTs are crucial, for example, thermal property and density prediction for composite materials with BNNTs embedded.

  17. Intensification of microalgae drying and oil extraction process by vapor recompression and heat integration.

    PubMed

    Song, Chunfeng; Liu, Qingling; Ji, Na; Deng, Shuai; Zhao, Jun; Kitamura, Yutaka

    2016-05-01

    Reducing energy penalty caused by drying and oil extraction is the most critical challenge in microalgae biodiesel production. In this study, vapor recompression and heat integration are utilized to optimize the performance of wet microalgae drying and oil extraction. In the microalgae drying stage, the hot exhaust stream is recompressed and coupled with wet microalgae to recover the condensate heat. In the oil extraction stage, the exergy rate of recovered solvent is also elevated by compressor and then exchanged heat with feed and bottom stream in the distillation column. Energy and mass balance of the intensified process is investigated and compared with the conventional microalgae drying-extraction process. The simulation results indicated that the total energy consumption of the intensified process can be saved by 52.4% of the conventional route.

  18. Modeling of a heat sink and high heat flux vapor chamber

    NASA Astrophysics Data System (ADS)

    Vadnjal, Aleksander

    An increasing demand for a higher heat flux removal capability within a smaller volume for high power electronics led us to focus on a novel cold plate design. A high heat flux evaporator and micro channel heat sink are the main components of a cold plate which is capable of removing couple of 100 W/cm2. In order to describe performance of such porous media device a proper modeling has to be addressed. A universal approach based on the volume average theory (VAT) to transport phenomena in porous media is shown. An approach on how to treat the closure for momentum and energy equations is addressed and a proper definition for friction factors and heat transfer coefficients are discussed. A numerical scheme using a solution to Navier-Stokes equations over a representative elementary volume (REV) and the use of VAT is developed to show how to compute friction factors and heat transfer coefficients. The calculation show good agreement with the experimental data. For the heat transfer coefficient closure, a proper average for both fluid and solid is investigated. Different types of heating are also investigated in order to determine how it influences the heat transfer coefficient. A higher heat fluxes in small area condensers led us to the micro channels in contrast to the classical heat fin design. A micro channel can have various shapes to enhance heat transfer, but the shape that will lead to a higher heat flux removal with a moderate pumping power needs to be determined. The standard micro-channel terminology is usually used for channels with a simple cross section, e.g. square, round, triangle, etc., but here the micro channel cross section is going to be expanded to describe more complicated and interconnected micro scale channel cross sections. The micro channel geometries explored are pin fins (in-line and staggered) and sintered porous micro channels. The problem solved here is a conjugate problem involving two heat transfer mechanisms; (1) porous media

  19. Quantitative model of vapor dominated geothermal reservoirs as heat pipes in fractured porous rock

    SciTech Connect

    Pruess, K.

    1985-03-01

    We present a numerical model of vapor-dominated reservoirs which is based on the well-known conceptual model of White, Muffler, and Truesdell. Computer simulations show that upon heat recharge at the base, a single phase liquid-dominated geothermal reservoir in fractured rock with low matrix permeability will evolve into a two-phase reservoir with B.P.D. (boiling point-for-depth) pressure and temperature profiles. A rather limited discharge event through cracks in the caprock, involving loss of only a few percent of fluids in place, is sufficient to set the system off to evolve a vapor-dominated state. The attributes of this state are discussed, and some features requiring further clarification are identified. 26 refs., 5 figs.

  20. Effects of detailed droplet heating models on turbulent sprays vaporization behavior

    NASA Technical Reports Server (NTRS)

    Mawid, M. A.

    1993-01-01

    The effects of three different droplet heating models on the vaporization history and internal structure of turbulent liquid fuel sprays were investigated. The models considered were the infinite-diffusion, diffusion-limit, and effective-conductivity models. A numerical solution for the models was developed and implemented in the KIVA-II computer code. Low temperature and relatively high temperature numerical studies were conducted. The low temperature computations were compared with existing experimental data. The comparisons showed that while the infinite-diffusion and diffusion-limit models respectively overpredicted and underpredicted the fuel vapor peak concentration and distribution in the combustor, the effective-conductivity model gave results that were in better agreement with measurements. A limited study for the high temperature case was performed due to lack of experimental data and predictions using the three models were compared with each other.

  1. Mathematical simulation of heating effects in a static diode-pumped vapor rubidium cell

    NASA Astrophysics Data System (ADS)

    Zhang, Wei; Wang, You; Han, Juhong; Cai, He; Xue, Liangping; Wang, Hongyuan

    2015-02-01

    Diode-pumped alkali lasers (DPALs) have attracted a lot of interests in the recent years because of their high Stokes efficiency, good beam quality, compact size, and near-infrared emission wavelengths. Until now, the thermal features have been only analyzed in an open alkali cell. In this report, we established a mathematical model to examine the heating effect of a static sealed rubidium cell by means of a Finite Difference (FD) procedure. After assuming the absorption coefficient of the alkali vapor, the temperature distributions of a real sealed rubidium vapor cell have been acquired for different powers and beam waists of the pump. The analytic conclusions would be helpful in designing a feasible DPAL.

  2. Heat conversion alternative petrochemical complexes efficiency

    NASA Astrophysics Data System (ADS)

    Mrakin, A. N.; Selivanov, A. A.; Morev, A. A.; Batrakov, P. A.; Kulbyakina, A. V.; Sotnikov, D. G.

    2017-08-01

    The paper presents the energy and economic efficiency calculation results of the petrochemical complexes based upon the sulfur oil shales processing by solid (ash) heat-carrier low-temperature carbonization plants by Galoter technology. The criterion for such enterprises fuel efficiency determining was developed on the base of the exergy methodology taking into account the recurrent publications consolidation. In this case, in supplying the consumers with paving bitumen, motor benzol, thiophene, toluene, 2-methylthiophene, xylene, gas sulfur, complex thermodynamic effectiveness was founded to amount to 53 %, and if ash residue realization is possible then it was founded to be to 70 %. The project economic attractiveness determining studies depending on the feedstock cost, its delivery way and investments amount changing were conducted.

  3. A correlation to predict the heat flux on the air-side of a vapor chamber with overturn-U flattened tubes

    NASA Astrophysics Data System (ADS)

    Srimuang, Wasan; Limkaisang, Viroj

    2016-08-01

    The heat transfer characteristics of a conventional vapor chamber (CVC) and a loop vapor chamber (LVC) are compared. The vapor chambers consisted of a stainless steel box with different covers. The results indicated that the heat flux and convective heat transfer coefficient of the air-side of LVC is higher than CVC. An empirical correlation was developed to predict the convective heat transfer coefficient of the air-side of the LVC.

  4. Pulse Detonation Engine Thrust Tube Heat Exchanger for Flash Vaporization and Supercritical Heating of JP-8

    DTIC Science & Technology

    2005-03-01

    was 38.1 cm long. The short heat exchanger did not have the helical flow coil installed. The same size inlet and outlet fittings were used and...three at the top and three at the bottom of the heat exchanger. The axial positions were determined by the helical coil geometry within the heat...HX Inlet HX Outlet Helical Coil - External Thermocouple T-1 B-1B-3 B-2 T-3 T-2 B - Bottom T - Top Figure 39. External thermocouple

  5. Open-cycle vapor compression heat pump. Annual progress report for 1980

    SciTech Connect

    Sakhuja, R.; Becker, F.E.

    1981-05-05

    Approximately 10 percent of U.S. energy is used by industry in the form of process steam at 100 psi or less. In many industrial plants, a portion of this steam is simply vented to the atmosphere or condensed after use in the process because it cannot be fully utilized or economically recovered. Also, a great amount of low-grade heat energy is wasted because it cannot be economically recovered. Recovery and upgrading of these low-grade steam or waste heat sources offers a great potential of energy conservation. Thermo Electron is developing an open cycle vapor compression steam heat pump to meet this objective. The system utilizes excess low-pressure steam or that produced from an industrial excess heat source with a waste heat boiler and compresses this steam to the desired pressure level for process use. The compressor is driven by a prime mover such as a gas turbine, gas engine, etc. The prime mover exhaust heat also can be recovered to generate additional process steam. The fuel consumption of this system can be as low as 30 to 50 percent in comparison to a direct-fired boiler over the expected range of process conditions. Simple payback periods as low as one year can be achieved.

  6. Initial Thermal Modeling of the Constrained Vapor Bubble Heat Exchanger Using TSS/SINDA

    NASA Astrophysics Data System (ADS)

    Basu, S.; Wayner, P. C., Jr.; Plawsky, J. L.

    2002-07-01

    Heat transfer systems operating under interfacial free-energy gradients to control the fluid flow are simple and light due to the absence of mechanical pumps. These have been proposed as reliable cooling systems in microgravity environments (Wayner, 1999). The Constrained Vapor Bubble (CVB) heat exchanger is being designed as a microgravity (mu-g) fluid physics experiment for the Fluids Integrated Rack (FIR) aboard the International Space Station (ISS). The aim of this study is to characterize the heat flow mechanisms of such a device operating as a wickless heat pipe, using the Thermal Synthesizer System/Systems Improved Numerical Differencing Analyzer (TSS/SINDA) software. The geometry and nodal meshwork was created using TSS, the graphics interface to SINDA. A SINDA (thermal) model was created to study steady state and transient solutions to heat transfer under the influence of conduction, convection and radiation. Experiments were performed with the CVB in vacuum and air, for various power inputs. An initial thermal model using TSS-SINDA is presented for the dry, evacuated CVB cell. The temperature profile data collected from the experiments were compared to the results of the model to provide significant insights to the losses due to radiation and convection. In view of expected flight-data trends (where convection is essentially negligible), the importance of radiation is discussed. The presence of a good heater-insulation is essential for high heat input to the cell.

  7. Disjoining pressure and capillarity in the constrained vapor bubble heat transfer system.

    PubMed

    Chatterjee, Arya; Plawsky, Joel L; Wayner, Peter C

    2011-10-14

    Using the disjoining pressure concept in a seminal paper, Derjaguin, Nerpin and Churaev demonstrated that isothermal liquid flow in a very thin film on the walls of a capillary tube enhances the rate of evaporation of moisture by several times. The objective of this review is to present the evolution of the use of Churaev's seminal research in the development of the Constrained Vapor Bubble (CVB) heat transfer system. In this non-isothermal "wickless heat pipe", liquid and vapor flow results from gradients in the intermolecular force field, which depend on the disjoining pressure, capillarity and temperature. A Kelvin-Clapeyron model allowed the use of the disjoining pressure to be expanded to describe non-isothermal heat, mass and momentum transport processes. The intermolecular force field described by the convenient disjoining pressure model is the boundary condition for "suction" and stability at the leading edge of the evaporating curved flow field. As demonstrated by the non-isothermal results, applications that depend on the characteristics of the evaporating meniscus are legion.

  8. Determination of Graphite-Liquid-Vapor Triple Point by Laser Heating

    DTIC Science & Technology

    1976-01-30

    Graphite-liquid-vapor triple point and melting temperatures of graphite 23 7. Sample No. 152 at 4140 K and 146 atm of neon 24 8. Same as...micrograph of Sample No. 152 containing a droplet of frozen liquid approximately 0.4 mm in size. This sample was heated to 4140 K under 146 atm of...graphite. -23- Fig. 7. Sample No. 152 at 4140 K and 146 atm of neon (Electron micrograph. Liquid droplet is in center.) ■24- Fig. 8

  9. Carbon dioxide, water vapor and sensible heat fluxes over a tallgrass prairie

    NASA Astrophysics Data System (ADS)

    Verma, Shashi B.; Kim, Joon; Clement, Robert J.

    1989-01-01

    Fluxes of CO2, water vapor and sensible heat were measured in a grassland ecosystem near Manhattan, Kansas, employing the eddy correlation technique. The vegetation at this site is dominated by big bluestem ( Andropogon gerardii), switchgrass ( Panicum virgatum), and indiangrass ( Sorghastrum nutans). Diurnal patterns of the energy budget components and CO2 fluxes are evaluated on a few selected days. Influence of high atmospheric evaporative demand and low availability of soil water are examined on (a) energy partitioning, and (b) the magnitudes and patterns of atmospheric carbon dioxide exchange.

  10. Process for utilizing the waste heat content of condensate and/or vapor produced in the manufacture of sugar

    SciTech Connect

    Huber, H.; Schiweck, H.

    1981-09-22

    A process is provided for utilizing the waste heat content of condensate and/or vapor produced in the manufacture of sugar in which thin juice is cooled, subjected to one or more stages of flash evaporation to concentrate and further cool the juice, after which it is heated with condensate and/or vapor produced elsewhere in the sugar manufacturing process and with incoming thin juice thereby heating the outgoing juice to substantially its original temperature and providing the cooling of the incoming thin juice. In another embodiment completely purified thin juice is concentrated in a multiple effect evaporating plant wherein the vapor produced in the final evaporator is compressed and is returned selectively to one of the preceding evaporators of the evaporating plant for use in heating the juice.

  11. Importance of soil heating, liquid water loss, and vapor flow enhancement for evaporation

    NASA Astrophysics Data System (ADS)

    Novak, Michael D.

    2016-10-01

    Field measurements conducted by Cahill and Parlange (1998) are reanalyzed to verify if their conclusion that daytime peak values of 60-70 W m-2 of latent heat flux divergence occurred in the 7-10 cm soil layer of a drying Yolo silt loam when maximum values of surface latent heat flux are estimated to have been about 100 W m-2. The new analyses, as similar to theirs as possible, are validated using a numerical simulation of coupled soil moisture and heat flow based on Philip and de Vries (1957) as a test bed. The numerical simulation is extended to include the flow of air induced by diurnal soil heating and evaporative water loss to verify the flux divergence calculations reported in Parlange et al. (1998) that explained the findings of Cahill and Parlange (1998). It is shown that the conclusions of both of these papers are in error, so that the original version of the Philip and de Vries (1957) theory is consistent with their field measurements after all and the effects of airflow associated with soil heating and liquid water loss (and low-frequency barometric pressure variations also considered) are negligible in practice. In an additional investigation, enhancement of diffusive vapor flow (first postulated by Philip and de Vries (1957)) and discussed extensively in the literature since is shown to have negligible effects on cumulative evaporation under field conditions.

  12. Study on Operating Performance of Stirling Engine-Driven Vapor Compression Heat Pump System

    NASA Astrophysics Data System (ADS)

    Kagawa, Noboru

    Stirling engines have many unique advantages including higher thermal efficiencies, preferable exhaust gas characteristics, multi-fuel usage, and low noise and vibration. On the other hand, heat pump systems are very attractive for space heating and cooling, and industrial usage. There are several environmental merits of Stirling driven vapor compression (SDVC) systems. A design method for the SDVC, which is based on mathematical methods for Stirling and Ranking cycles, has been developed. The attractive SDVC performance using conventional and alternative refrigerants was shown. From the calculated Total Equivalent Warming Impact (TEWI) and operating costs, it became clear that the SDVC system with the alternative refrigerant has a higher potential as the future air-conditioning system.

  13. On-board Direct Eddy Flux Measurements of Heat, Water Vapor and Co2

    NASA Astrophysics Data System (ADS)

    Tsukamoto, O.; Takahashi, S.; Kono, T.; Yamashita, E.; Ishida, H.

    Direct eddy fluxes of heat(sensible and latent), water vapor and CO2 were measuted with on-board eddy flux system over the Pacific. Present authors are continueing direct eddy flux measurement on R/V MIRAI(JAMSTEC) cruising the Pacific. I addition to these routine heat flux evaluation, direct CO2 flux measurements were applied with LI- 7500 (Licor) and Kaijo sonic anemometer. The eddy flux system including CO2 sensor worked very well even in the moving ship. Small amplitude of turbulent fluctuations of CO2 were measured and it is found that CO2 was transported downward to sea surface during a month(Nov-Dec 2001) around 2N,138E. CO2 concentrations in the air and sea water were also measured and they also confirmed the CO2 sink. The automated real-time eddy flux system including ship motion correction has started and this can be applied to other cruising ships.

  14. Fluorine redistribution in a chemical vapor deposited tungsten/polycrystalline silicon gate structure during heat treatment

    NASA Astrophysics Data System (ADS)

    Eriksson, Th.; Carlsson, J.-O.; Keinonen, J.; Petersson, C. S.

    1988-09-01

    Fluorine redistribution during heat treatment of chemical vapor deposited tungsten/polycrystalline silicon gate structures was analyzed by the nuclear resonance broadening technique. The tungsten layer was deposited from a hydrogen/tungsten hexafluoride gas mixture. Upon heat treatment in the temperature range 1020-1325-K tungsten disilicide formation was observed using Rutherford backscattering spectrometry. In the as-deposited sample, the fluorine was accumulated at the tungsten/polycrystalline silicon interface. After silicide formation the fluorine was observed at the tungsten disilicide/polycrystalline silicon interface. At temperatures above 1120 K fluorine starts to diffuse through the polycrystalline silicon layer. A variation in the total fluorine content between the samples was also observed. The origin of the fluorine redistribution as well as the variation in the total fluorine content is discussed in connection to conceivable mechanisms.

  15. Fluorine redistribution in a chemical vapor deposited tungsten/polycrystalline silicon gate structure during heat treatment

    SciTech Connect

    Eriksson, T.; Carlsson, J.; Keinonen, J.; Petersson, C.S.

    1988-09-15

    Fluorine redistribution during heat treatment of chemical vapor deposited tungsten/polycrystalline silicon gate structures was analyzed by the nuclear resonance broadening technique. The tungsten layer was deposited from a hydrogen/tungsten hexafluoride gas mixture. Upon heat treatment in the temperature range 1020--1325-K tungsten disilicide formation was observed using Rutherford backscattering spectrometry. In the as-deposited sample, the fluorine was accumulated at the tungsten/polycrystalline silicon interface. After silicide formation the fluorine was observed at the tungsten disilicide/polycrystalline silicon interface. At temperatures above 1120 K fluorine starts to diffuse through the polycrystalline silicon layer. A variation in the total fluorine content between the samples was also observed. The origin of the fluorine redistribution as well as the variation in the total fluorine content is discussed in connection to conceivable mechanisms.

  16. High-temperature multipass cell for infrared spectroscopy of heated gases and vapors

    NASA Astrophysics Data System (ADS)

    Bartlome, R.; Baer, M.; Sigrist, M. W.

    2007-01-01

    In absorption spectroscopy, infrared spectra of heated gases or condensed samples in the vapor phase are usually recorded with a single pass heated gas cell. This device exhibits two orders of magnitude lower sensitivity than the high-temperature multipass cell presented in this article. Our device is a novel type of compact long path absorption cell that can withstand aggressive chemicals in addition to temperatures up to 723K. The construction of the cell and its technical features are described in detail, paying special attention to the mechanisms that compensate for thermal expansion and that allow the user to vary the optical path length under any thermal or vacuum condition. The cell may be used with a laser source or implemented within a Fourier transform infrared spectrometer. Its design is compatible with optical arrangements using astigmatic mirrors or spherical mirrors in a Herriott configuration. Here we implement a homebuilt Herriott-type cell with a total optical path length of up to 35m. In order to demonstrate the feasibility of the cell, methane and water vapor absorption lines showing dissimilar temperature effects on line intensity were recorded with the help of a mid-infrared laser source tunable between 3 and 4μm. Emphasis is put on lines that are too weak to be recorded with a single pass cell.

  17. High-temperature multipass cell for infrared spectroscopy of heated gases and vapors.

    PubMed

    Bartlome, R; Baer, M; Sigrist, M W

    2007-01-01

    In absorption spectroscopy, infrared spectra of heated gases or condensed samples in the vapor phase are usually recorded with a single pass heated gas cell. This device exhibits two orders of magnitude lower sensitivity than the high-temperature multipass cell presented in this article. Our device is a novel type of compact long path absorption cell that can withstand aggressive chemicals in addition to temperatures up to 723 K. The construction of the cell and its technical features are described in detail, paying special attention to the mechanisms that compensate for thermal expansion and that allow the user to vary the optical path length under any thermal or vacuum condition. The cell may be used with a laser source or implemented within a Fourier transform infrared spectrometer. Its design is compatible with optical arrangements using astigmatic mirrors or spherical mirrors in a Herriott configuration. Here we implement a homebuilt Herriott-type cell with a total optical path length of up to 35 m. In order to demonstrate the feasibility of the cell, methane and water vapor absorption lines showing dissimilar temperature effects on line intensity were recorded with the help of a mid-infrared laser source tunable between 3 and 4 microm. Emphasis is put on lines that are too weak to be recorded with a single pass cell.

  18. Pressure intelligent control strategy of Waste heat recovery system of converter vapors

    NASA Astrophysics Data System (ADS)

    Feng, Xugang; Wu, Zhiwei; Zhang, Jiayan; Qian, Hong

    2013-01-01

    The converter gas evaporative cooling system is mainly used for absorbing heat in the high temperature exhaust gas which produced by the oxygen blowing reaction. Vaporization cooling steam pressure control system of converter is a nonlinear, time-varying, lagging behind, close coupling of multivariable control object. This article based on the analysis of converter operation characteristics of evaporation cooling system, of vaporization in a production run of pipe pressure variation and disturbance factors.For the dynamic characteristics of the controlled objects,we have improved the conventional PID control scheme.In Oxygen blowing process, we make intelligent control by using fuzzy-PID cascade control method and adjusting the Lance,that it can realize the optimization of the boiler steam pressure control.By design simulation, results show that the design has a good control not only ensures drum steam pressure in the context of security, enabling efficient conversion of waste heat.And the converter of 1800 flue gas through pipes and cool and dust removal also can be cooled to about 800. Therefore the converter haze evaporative cooling system has achieved to the converter haze temperature decrease effect and enhanced to the coal gas returns-ratio.

  19. Atmospheric net transport of water vapor and latent heat across 70°S

    NASA Astrophysics Data System (ADS)

    Giovinetto, M. B.; Bromwich, D. H.; Wendler, G.

    1992-01-01

    The annual net atmospheric transports of water vapor and latent heat poleward across 70°S are estimated using the latest compilation of surface mass balance for the Antarctic ice sheet and new estimates of precipitation and evaporation in sectors of the southern oceans and of seaward drifting snow transport in particular sectors of the ice sheet. The mass and energy exchange rates at the ice sheet-atmosphere and ocean-atmosphere interfaces are integrated strictly for areas within that latitude. The estimates of net southward water vapor transport (6.6 ± 1.3 kg m-1 s-1) and latent heat transport (18.9 ± 3.6 MJ m-1 s-1) are larger than reported in all preceding studies, based on atmospheric advection and moisture data collected at stations located between 66°S and 80°S, and are generally in agreement with those based on surface mass balance data and seaward drifting snow transport across the ice terminus which extends between 65°S and 79°S.

  20. Intraparticle heat and mass transfer characteristics of silica-gel/water vapor adsorption

    SciTech Connect

    Yamamoto, Eri; Watanabe, Fujio; Hasatani, Masanobu

    1999-07-01

    Recently, highly efficient energy utilization systems which extensively employ adsorption phenomena such as pressure swing adsorption, heat storage, adsorption heat pump, etc. are being regarded as one of the countermeasures for environmental issues such as green house effect and ozone layer destruction. An Adsorption Heat Pump (AHP) has been investigated as one of the important techniques via which cold heat energy is obtained from waste thermal energy below 373K without using electricity and CFCs. An AHP normally consists of an adsorber and an evaporator/condenser and cold heat energy is generated by latent heat of evaporation during adsorption process. For realizing the AHP technology, it has been pointed out that the development of an adsorber with optimum heat and mass transfer characteristics is essentially important. In this study, experimental studies were carried out which was based on the data of temperature inside the adsorbent particle and adsorptivity profiles at the adsorption/desorption process by volumetric method. To clarify adsorption mechanism relatively large silica-gel particle (7 mm f) was used. Temperature distribution in the particle is determined at the center, at one half radius in the radial direction and at the surface by using very thin (30 mm f) thermocouples. The temperatures at these points simultaneously increase/decrease as soon as the adsorption/desorption started, reached their respective maximum/minimum values and then return to initial temperature. The temperature profiles for the adsorption process show that the temperature at the surface is initially slightly higher than the other two points. All three points reached their respective maximum temperature at the same time with the temperature at the center point the highest and at the surface the lowest. The temperature profiles during the desorptive process are almost exactly the opposite to that of the adsorption process. This shows that the adsorption phenomena can take

  1. SO2:H2O surface complex found at the vapor/water interface.

    PubMed

    Tarbuck, Teresa L; Richmond, Geraldine L

    2005-12-07

    A weakly bonded SO2:H2O surface complex is found at the vapor/water interface prior to the reaction and dissolution of SO2 into the aqueous phase. The results have important implications for understanding the formation of atmospheric aerosols and understanding the atmospheric sulfur cycle.

  2. Numerical simulation of coupled fluid flow and heat transfer characteristics in a submerged combustion vaporizer

    NASA Astrophysics Data System (ADS)

    Han, Chang-Liang; Ren, Jing-Jie; Wang, Yan-Qing; Dong, Wen-Ping; Bi, Ming-Shu

    2016-12-01

    Submerged combustion vaporizer (SCV) has been widely employed in Liquefied Natural Gas (LNG) receiving terminals as the main peaking-shaving facility. In the current work, numerical simulation was carried out to study the intrinsic fluid flow and heat transfer characteristics inside the SCV. After the verification of the numerical model and method with the experimental data, detailed results about flow field and temperature field were presented to have an understanding of the principle of shell-side heat transfer enhancement. The distributions of local LNG temperature, wall temperature, water bath temperature and heat transfer coefficient along the tube length were also revealed. Moreover, the influences of main operating parameters such as flue gas temperature, inlet LNG velocity, inlet LNG pressure, static water height and flue gas flux on the system performance were systematically investigated. Finally, based on current simulation results, two empirical correlations were proposed to predict the coupled heat transfer performance of SCV. The simulated results could provide some insight into the design and optimization of SCV.

  3. Differentiation of complex vapor mixtures using versatile DNA-carbon nanotube chemical sensor arrays.

    PubMed

    Kybert, Nicholas J; Lerner, Mitchell B; Yodh, Jeremy S; Preti, George; Johnson, A T Charlie

    2013-03-26

    Vapor sensors based on functionalized carbon nanotubes (NTs) have shown great promise, with high sensitivity conferred by the reduced dimensionality and exceptional electronic properties of the NT. Critical challenges in the development of NT-based sensor arrays for chemical detection include the demonstration of reproducible fabrication methods and functionalization schemes that provide high chemical diversity to the resulting sensors. Here, we outline a scalable approach to fabricating arrays of vapor sensors consisting of NT field effect transistors functionalized with single-stranded DNA (DNA-NT). DNA-NT sensors were highly reproducible, with responses that could be described through equilibrium thermodynamics. Target analytes were detected even in large backgrounds of volatile interferents. DNA-NT sensors were able to discriminate between highly similar molecules, including structural isomers and enantiomers. The sensors were also able to detect subtle variations in complex vapors, including mixtures of structural isomers and mixtures of many volatile organic compounds characteristic of humans.

  4. Secondary electrospray ionization of complex vapor mixtures. Theoretical and experimental approach.

    PubMed

    Vidal-de-Miguel, Guillermo; Herrero, Ana

    2012-06-01

    In secondary electrospray ionization (SESI) systems, gaseous analytes exposed to an electrospray plume become ionized after charge is transferred from the charging electrosprayed particles (the charging agent) to the vapor species. Currently available SESI models are valid for simplified systems having only one type of electrosprayed species, which ionizes only one single vapor species, and for the limit of low vapor concentration. More realistic models require considering other effects. Here we develop a theoretical model that accounts for the effects of high vapor concentration, saturation effects, interferences between different vapor species, and electrosprays producing different types of species from the liquid phase. In spite of the relatively high complexity of the problem, we find simple relations between the different ionic species concentrations that hold independently of the particular ion source configuration. Our model suggests that an ideal SESI system should use highly concentrated charging agents composed preferably of only one dominating species with low mobility. Experimental measurements with a MeOH-H(2)O-NH(3) electrospray and a mixture of fatty acids and lactic acid served to test the theory, which gives good qualitative results. These results also suggest that the SESI ionization mechanism is primarily based on ions rather than on charged droplets.

  5. A numerical study of heat and water vapor transfer in MDCT-based human airway models.

    PubMed

    Wu, Dan; Tawhai, Merryn H; Hoffman, Eric A; Lin, Ching-Long

    2014-10-01

    A three-dimensional (3D) thermo-fluid model is developed to study regional distributions of temperature and water vapor in three multi-detector row computed-tomography-based human airways with minute ventilations of 6, 15 and 30 L/min. A one-dimensional (1D) model is also solved to provide necessary initial and boundary conditions for the 3D model. Both 3D and 1D predicted temperature distributions agree well with available in vivo measurement data. On inspiration, the 3D cold high-speed air stream is split at the bifurcation to form secondary flows, with its cold regions biased toward the inner wall. The cold air flowing along the wall is warmed up more rapidly than the air in the lumen center. The repeated splitting pattern of air streams caused by bifurcations acts as an effective mechanism for rapid heat and mass transfer in 3D. This provides a key difference from the 1D model, where heating relies largely on diffusion in the radial direction, thus significantly affecting gradient-dependent variables, such as energy flux and water loss rate. We then propose the correlations for respective heat and mass transfer in the airways of up to 6 generations: [Formula: see text] and [Formula: see text], where Nu is the Nusselt number, Sh is the Sherwood number, Re is the branch Reynolds number, D a is the airway equivalent diameter, and [Formula: see text] is the tracheal equivalent diameter.

  6. Probing heat diffusion after pulsed-laser-induced breakdown in a metal vapor

    SciTech Connect

    Zapka, W.; Tam, A.C.

    1982-02-01

    We have used a pulsed dye-laser beam at 6010 A, of 1-..mu..sec duration and < or approx. =1-mJ energy, to produce a line plasma in a Cs metal vapor. This produces a line source of large thermal energy. The heat diffusion after the laser pulse can be studied by transmission monitoring of a weak cw He--Ne laser beam that is parallel to but separated from the pulse laser beam by an adjustable displacement. This is possible because the He--Ne beam is absorbed by the minority Cs/sub 2/ molecules but not by the majority Cs atoms; as the heat pulse diffuses through the probe beam, the transient temperature increase causes a corresponding change in the population distribution of the Cs/sub 2/ molecules and hence a transient increase in transmission of the probe beam. In other words, the Cs/sub 2/ workd like a thermometer. Our work demonstrates a new and simple method to measure heat diffusion in a well-defined geometry, and it is especially suitable for use in a hot corrosive system because it is a noncontact method.

  7. Modeling water vapor and heat transfer in the normal and the intubated airways.

    PubMed

    Tawhai, Merryn H; Hunter, Peter J

    2004-04-01

    Intubation of the artificially ventilated patient with an endotracheal tube bypasses the usual conditioning regions of the nose and mouth. In this situation any deficit in heat or moisture in the air is compensated for by evaporation and thermal transfer from the pulmonary airway walls. To study the dynamics of heat and water transport in the intubated airway, a coupled system of nonlinear equations is solved in airway models with symmetric geometry and anatomically based geometry. Radial distribution of heat, water vapor, and velocity in the airway are described by power-law equations. Solution of the time-dependent system of equations yields dynamic airstream and mucosal temperatures and air humidity. Comparison of model results with two independent experimental studies in the normal and intubated airway shows a close correlation over a wide range of minute ventilation. Using the anatomically based model a range of spatially distributed temperature paths is demonstrated, which highlights the model's ability to predict thermal behavior in airway regions currently inaccessible to measurement. Accurate representation of conducting airway geometry is shown to be necessary for simulating mouth-breathing at rates between 15 and 100 l x min(-1), but symmetric geometry is adequate for the low minute ventilation and warm inspired air conditions that are generally supplied to the intubated patient.

  8. DETERMINATION OF HEAT TRANSFER COEFFICIENTS FOR FRENCH PLASTIC SEMEN STRAW SUSPENDED IN STATIC NITROGEN VAPOR OVER LIQUID NITROGEN.

    PubMed

    Santo, M V; Sansinena, M; Chirife, J; Zaritzky, N

    2015-01-01

    The use of mathematical models describing heat transfer during the freezing process is useful for the improvement of cryopreservation protocols. A widespread practice for cryopreservation of spermatozoa of domestic animal species consists of suspending plastic straws in nitrogen vapor before plunging into liquid nitrogen. Knowledge of surface heat transfer coefficient (h) is mandatory for computational modelling; however, h values for nitrogen vapor are not available. In the present study, surface heat transfer coefficients for plastic French straws immersed in nitrogen vapor over liquid nitrogen was determined; vertical and horizontal positions were considered. Heat transfer coefficients were determined from the measurement of time-temperature curves and from numerical solution of heat transfer partial differential equation under transient conditions using finite elements. The h values experimentally obtained for horizontal and vertically placed straws were compared to those calculated using correlations based on the Nusselt number for natural convection. For horizontal straws the average obtained value was h=12.5 ± 1.2 W m(2) K and in the case of vertical straws h=16 ± 2.48 W m(2) K. The numerical simulation validated against experimental measurements, combined with accurate h values provides a reliable tool for the prediction of freezing curves of semen-filled straws immersed in nitrogen vapor. The present study contributes to the understanding of the cryopreservation techniques for sperm freezing based on engineering concepts, improving the cooling protocols and the manipulation of the straws.

  9. The interaction of flow, heat transfer, and free interfaces in an electron-beam vaporization system for metals

    SciTech Connect

    Westerberg, K.W.; McClelland, M.A.; Finlayson, B.A.

    1994-11-01

    A numerical analysis is made of the liquid flow and energy transport in a system to vaporize metals. The energy from an electron beam heats metal confined in a water-cooled crucible. Metal vaporizes from a hot pool of circulating liquid which is surrounded by a shell of its own solid. Flow in the pool is strongly driven by temperature-induced buoyancy and capillary forces and is located in the transition region between laminar and turbulent flow. At high vaporization rates, the thrust of the departing vapor forms a trench at the beam impact site. A modified finite element method is used to calculate the flow and temperature fields coupled with the interface locations. The mesh is structured with spines that stretch and pivot as the interfaces move. The discretized equations are arranged in an {open_quotes}arrow{close_quotes} matrix and solved using the Newton-Raphson method. The electron-beam power and width are varied for cases involving the high-rate vaporization of aluminum. Attention is focused on the interaction of vaporization, liquid flow, and heat transport in the trench area.

  10. Coupled heat and vapor transport: The thermostat effect of a freely evaporating land surface

    NASA Astrophysics Data System (ADS)

    Szilagyi, Jozsef; Schepers, Aaron

    2014-01-01

    Analytical solutions of the 2-D heat and vapor transport equations for a surface moisture jump are often based on a constant streamwise temperature (Tws) assumption over the wet vegetated surface. By analyzing 90 thermal infrared images taken over center-pivot irrigated areas in Nebraska, it has been demonstrated for the first time that such an assumption is realistic. Average temperature difference between the perimeter and core of the irrigated full or half circles stayed between -0.11 and 0.09°C (standard deviation of 0.25-0.41°C). It was further demonstrated that wet-bulb temperatures (a proxy of Tws) remain near constant during drying of the environment when net radiation and wind conditions stay largely unchanged, enabling estimation of Tws at any stage of drying, thus improving evaporation estimates of the Priestley-Taylor equation in arid and semiarid environments.

  11. Induction heating pure vapor source of high temperature melting point materials on electron cyclotron resonance ion source

    SciTech Connect

    Kutsumi, Osamu; Kato, Yushi; Matsui, Yuuki; Sato, Fuminobu; Iida, Toshiyuki; Kitagawa, Atsushi; Muramatsu, Masayuki; Uchida, Takashi; Yoshida, Yoshikazu

    2010-02-15

    Multicharged ions that are needed are produced from solid pure material with high melting point in an electron cyclotron resonance ion source. We develop an evaporator by using induction heating (IH) with multilayer induction coil, which is made from bare molybdenum or tungsten wire without water cooling and surrounding the pure vaporized material. We optimize the shapes of induction coil and vaporized materials and operation of rf power supply. We conduct experiment to investigate the reproducibility and stability in the operation and heating efficiency. IH evaporator produces pure material vapor because materials directly heated by eddy currents have no contact with insulated materials, which are usually impurity gas sources. The power and the frequency of the induction currents range from 100 to 900 W and from 48 to 23 kHz, respectively. The working pressure is about 10{sup -4}-10{sup -3} Pa. We measure the temperature of the vaporized materials with different shapes, and compare them with the result of modeling. We estimate the efficiency of the IH vapor source. We are aiming at the evaporator's higher melting point material than that of iron.

  12. Induction heating pure vapor source of high temperature melting point materials on electron cyclotron resonance ion source.

    PubMed

    Kutsumi, Osamu; Kato, Yushi; Matsui, Yuuki; Kitagawa, Atsushi; Muramatsu, Masayuki; Uchida, Takashi; Yoshida, Yoshikazu; Sato, Fuminobu; Iida, Toshiyuki

    2010-02-01

    Multicharged ions that are needed are produced from solid pure material with high melting point in an electron cyclotron resonance ion source. We develop an evaporator by using induction heating (IH) with multilayer induction coil, which is made from bare molybdenum or tungsten wire without water cooling and surrounding the pure vaporized material. We optimize the shapes of induction coil and vaporized materials and operation of rf power supply. We conduct experiment to investigate the reproducibility and stability in the operation and heating efficiency. IH evaporator produces pure material vapor because materials directly heated by eddy currents have no contact with insulated materials, which are usually impurity gas sources. The power and the frequency of the induction currents range from 100 to 900 W and from 48 to 23 kHz, respectively. The working pressure is about 10(-4)-10(-3) Pa. We measure the temperature of the vaporized materials with different shapes, and compare them with the result of modeling. We estimate the efficiency of the IH vapor source. We are aiming at the evaporator's higher melting point material than that of iron.

  13. Vapor pressures and heats of vaporization of primary coal tars. Quarterly technical progress report, 1 July 1993--30 September 1993

    SciTech Connect

    Suuberg, E.M.; Oja, V.; Lilly, W.D.

    1993-12-31

    There is significant current interest in general area of coal pyrolysis, particularly with respect to comprehensive models of this complicated phenomenon. This interest derives from the central role of pyrolysis in all thermally driven coal conversion processes -- gasification, combustion, liquefaction, mild gasification, or thermal benefication. There remain several key data needs in these application areas. Among them is a need for more reliable correlation for prediction of vapor pressure of heavy, primary coal tars. Such information is important in design of all coal conversion processes, in which the volatility of tarry products is of major concern. Only very limited correlations exist, and these are not considered reliable to even an order of magnitude when applied to tars. The present project seeks to address this important gap in the near term by direct measurement of vapor pressures of coal tar fractions, by application of well-established techniques and modifications thereof. The principal objectives of the program are to: (1) obtain data on the vapor pressures and heats of vaporization of tars from a range of ranks of coal, (2) develop correlations based on a minimum set of conveniently measurable characteristics of the tars, (3) develop equipment that would allow performing such measurements in a reliable, straightforward fashion. Results of the literature survey are compiled. The experimental tasks have been concerned with setup and calibration.

  14. Smoothing HCCI heat release with vaporization-cooling-induced thermal stratification using ethanol.

    SciTech Connect

    Dec, John E.; Sjoberg, Carl-Magnus G.

    2010-12-01

    Ethanol and ethanol/gasoline blends are being widely considered as alternative fuels for light-duty automotive applications. At the same time, HCCI combustion has the potential to provide high efficiency and ultra-low exhaust emissions. However, the application of HCCI is typically limited to low and moderate loads because of unacceptably high heat-release rates (HRR) at higher fueling rates. This work investigates the potential of lowering the HCCI HRR at high loads by using partial fuel stratification to increase the in-cylinder thermal stratification. This strategy is based on ethanol's high heat of vaporization combined with its true single-stage ignition characteristics. Using partial fuel stratification, the strong fuel-vaporization cooling produces thermal stratification due to variations in the amount of fuel vaporization in different parts of the combustion chamber. The low sensitivity of the autoignition reactions to variations of the local fuel concentration allows the temperature variations to govern the combustion event. This results in a sequential autoignition event from leaner and hotter zones to richer and colder zones, lowering the overall combustion rate compared to operation with a uniform fuel/air mixture. The amount of partial fuel stratification was varied by adjusting the fraction of fuel injected late to produce stratification, and also by changing the timing of the late injection. The experiments show that a combination of 60-70% premixed charge and injection of 30-40 % of the fuel at 80{sup o}CA before TDC is effective for smoothing the HRR. With CA50 held fixed, this increases the burn duration by 55% and reduces the maximum pressure-rise rate by 40%. Combustion stability remains high but engine-out NO{sub x} has to be monitored carefully. For operation with strong reduction of the peak HRR, ISNO{sub x} rises to around 0.20 g/kWh for an IMEP{sub g} of 440 kPa. The single-cylinder HCCI research engine was operated naturally aspirated

  15. Heat pipes for spacecraft temperature control: An assessment of the state-of-the-art. [gas, vapor, liquid, and voltage control

    NASA Technical Reports Server (NTRS)

    Groll, M.; Kirkpatrick, J. P.

    1976-01-01

    Spacecraft applications that require the efficient cooling of high-powered components, the precise temperature control of sensitive electronic and optical components, and the protection of cooled components from temporary, adverse environmental conditions are increasing. Heat pipes using gas, vapor, liquid, or voltage control to provide variable conductance or diode thermal behavior have been and are continuing to be developed to meet increasingly difficult requirements. The various control techniques are critically evaluated using characteristic features and properties, including heat transport capability, volume and mass requirements, complexity and ease of fabrication, reliability, and control characteristics. As a result, advantages and disadvantages of specific approaches are derived and discussed. Using four development levels, the state-of-the-art of the various heat pipe temperature control techniques is assessed.

  16. Preliminary analysis of NAPL behavior in soil-heated vapor extraction for in-situ environmental restoration

    SciTech Connect

    Webb, S.W.; Phelan, J.M.

    1995-10-01

    Simulations of soil-heated vapor extraction have been performed to evaluate the NAPL removal performance as a function of borehole vacuum. The possibility of loss of NAPL containment, or NAPL migration into the unheated soil, is also evaluated in the simulations. A practical warning sign indicating migration of NAPL into the unheated zone is discussed.

  17. Simulation of the early startup period of high-temperature heat pipes from the frozen state by a rarefied vapor self-diffusion model

    NASA Technical Reports Server (NTRS)

    Cao, Y.; Faghri, A.

    1993-01-01

    The heat pipe startup process is described physically and is divided into five periods for convenience of analysis. The literature survey revealed that none of the previous attempts to simulate the heat pipe startup process numerically were successful, since the rarefied vapor flow in the heat pipe was not considered. Therefore, a rarefied vapor self-diffusion model is proposed, and the early startup periods, in which the rarefied vapor flow is dominant within the heat pipe, are first simulated numerically. The numerical results show that large vapor density gradients existed along the heat pipe length, and the vapor flow reaches supersonic velocities when the density is extremely low. The numerical results are compared with the experimental data of the early startup period with good agreement.

  18. A non-equilibrium model for soil heating and moisture transport during extreme surface heating: the soil (heat-moisture-vapor) HMV-Model Version 1

    NASA Astrophysics Data System (ADS)

    Massman, W. J.

    2015-11-01

    Increased use of prescribed fire by land managers and the increasing likelihood of wildfires due to climate change require an improved modeling capability of extreme heating of soils during fires. This issue is addressed here by developing and testing the soil (heat-moisture-vapor) HMV-model, a 1-D (one-dimensional) non-equilibrium (liquid-vapor phase change) model of soil evaporation that simulates the coupled simultaneous transport of heat, soil moisture, and water vapor. This model is intended for use with surface forcing ranging from daily solar cycles to extreme conditions encountered during fires. It employs a linearized Crank-Nicolson scheme for the conservation equations of energy and mass and its performance is evaluated against dynamic soil temperature and moisture observations, which were obtained during laboratory experiments on soil samples exposed to surface heat fluxes ranging between 10 000 and 50 000 W m-2. The Hertz-Knudsen equation is the basis for constructing the model's non-equilibrium evaporative source term. Some unusual aspects of the model that were found to be extremely important to the model's performance include (1) a dynamic (temperature and moisture potential dependent) condensation coefficient associated with the evaporative source term, (2) an infrared radiation component to the soil's thermal conductivity, and (3) a dynamic residual soil moisture. This last term, which is parameterized as a function of temperature and soil water potential, is incorporated into the water retention curve and hydraulic conductivity functions in order to improve the model's ability to capture the evaporative dynamics of the strongly bound soil moisture, which requires temperatures well beyond 150 °C to fully evaporate. The model also includes film flow, although this phenomenon did not contribute much to the model's overall performance. In general, the model simulates the laboratory-observed temperature dynamics quite well, but is less precise (but

  19. A Numerical Study of Heat and Water Vapor Transfer in MDCT-Based Human Airway Models

    PubMed Central

    Wu, Dan; Tawhai, Merryn H.; Hoffman, Eric A.; Lin, Ching-Long

    2014-01-01

    A three-dimensional (3D) thermo-fluid model is developed to study regional distributions of temperature and water vapor in three multi-detector row computed-tomography (MDCT)-basedhuman airwayswith minute ventilations of 6, 15 and 30 L/min. A one-dimensional (1D) model is also solved to provide necessary initial and boundary conditionsforthe 3D model. Both 3D and 1D predicted temperature distributions agree well with available in vivo measurement data. On inspiration, the 3D cold high-speed air stream is split at the bifurcation to form secondary flows, with its cold regions biased toward the inner wall. The cold air flowing along the wall is warmed up more rapidly than the air in the lumen center. The repeated splitting pattern of air streams caused by bifurcations acts as an effective mechanism for rapid heat and mass transfer in 3D. This provides a key difference from the 1D model, where heating relies largely on diffusion in the radial direction, thus significantly affecting gradient-dependent variables, such as energy flux and water loss rate. We then propose the correlations for respective heat and mass transfer in the airways of up to 6 generations: Nu=3.504(ReDaDt)0.277, R = 0.841 and Sh=3.652(ReDaDt)0.268, R = 0.825, where Nu is the Nusselt number, Sh is the Sherwood number, Re is the branch Reynolds number, Da is the airway equivalent diameter, and Dt is the tracheal equivalentdiameter. PMID:25081386

  20. Numerical Modeling of Coupled Heat Transport and Liquid Water and Water Vapor Flow in Geothermally Heated Ground at Norris Geyser Basin

    NASA Astrophysics Data System (ADS)

    Mohamed, R. A. M.; Jones, S. B.; Neale, C. M. U.

    2016-12-01

    Long-term monitoring of ground surface temperature and heat flow near hydrothermally active areas in Yellowstone National Park can help determine possible changes of the subsurface heat flow. Some of these changes may alter the safety of the park's visitors, rangers and scientists. The geothermal heated ground in Norris Geyser Basin in Yellowstone National Park receives heat from both the geothermal gradient and the atmospheric shortwave and longwave radiations. In this study a one dimensional numerical model was used to model the coupled movement of liquid water, water vapor, and heat in the top 10 cm soil layer near a hydrothermal crater in Norris Geyser Basin. The Hydrus 1D numerical model was used to simulate the coupled processes in order to optimize the soil hydraulic parameters. Parameter optimization was done using Marquardt-Levenberg type parameter optimization algorithm for variably saturated soil under steady state and transient flow conditions. The simulation of coupled heat transport and liquid water and water vapor flow in geothermally heated ground is a new application to Hydrus 1D. Preliminary results, however, showed that the calculated temperature and water content correlated well with observed patterns on both dry sunny days and wet days. The study explained the coupled processes at the ground-atmosphere boundary layer which can help determine possible changes within the subsurface heat flow from the geothermal source.

  1. Propellant Vaporization as a Criterion for Rocket-Engine Design; Experimental Performance, Vaporization and Heat-Transfer Rates with Various Propellant Combinations

    NASA Technical Reports Server (NTRS)

    Clark, Bruce J.; Hersch, Martin; Priem, Richard J.

    1959-01-01

    Experimental combustion efficiencies of eleven propellant combinations were determined as a function of chamber length. Efficiencies were measured in terms of characteristic exhaust velocities at three chamber lengths and in terms of gas velocities. The data were obtained in a nominal 200-pound-thrust rocket engine. Injector and engine configurations were kept essentially the same to allow comparison of the performance. The data, except for those on hydrazine and ammonia-fluorine, agreed with predicted results based on the assumption that vaporization of the propellants determines the rate of combustion. Decomposition in the liquid phase may be.responsible for the anomalous behavior of hydrazine. Over-all heat-transfer rates were also measured for each combination. These rates were close to the values predicted by standard heat-transfer calculations except for the combinations using ammonia.

  2. Vapor Grown Carbon Fiber/Phenolic Matrix Composites for Rocket Nozzles and Heat Shields

    NASA Technical Reports Server (NTRS)

    Patton, R. D.; Pittman, C. U., Jr.; Wang, L.; Day, A.; Hill, J. R.

    2001-01-01

    The ablation and mechanical and thermal properties of vapor grown carbon fiber (VGCF)/phenolic resin composites were evaluated to determine the potential of using this material in solid rocket motor nozzles. Composite specimens with varying VGCF loading (30%-50% wt) including one sample with ex-rayon carbon fiber plies were prepared and exposed to a plasma torch for 20 s with a heat flux of 16.5 MW/sq m at approximately 1650 C. Low erosion rates and little char formation were observed, confirming that these materials were promising for rocket motor nozzle materials. When fiber loadings increased, mechanical properties and ablative properties improved. The VGCF composites had low thermal conductivities (approximately 0.56 W/m-C) indicating they were good insulating materials. If a 65% fiber loading in VGCF composite can be achieved, then ablative properties are projected to be comparable to or better than the composite material currently used on the Space Shuttle Reusable Solid Rocket Motor (RSRM).

  3. An investigation into the output characteristics of a discharge-heated copper vapor laser

    NASA Astrophysics Data System (ADS)

    Wang, Tieh C.; Yang, Ching Y.

    1989-11-01

    The laser output characteristics of a discharge-heated copper vapor laser (CVL) were investigated at a charging voltage of 14.5 kV, laser tube temperature of 1450 C, pulse repetition rate (PRR) range from 0.5 to 9.5 kHz, and buffer gas pressures of 20 and 75 Torr. Changing buffer gas pressure from 20 to 75 Torr causes no significant variation of the rates of relaxation of metastable atoms. Increase of the current rise of pumping pulse with increasing PRR is the predominant factor for improving the laser behavior when PRR is greater than 3.5 kHz with buffer gas pressure of 20 Torr and when PRR is less than 4.5 kHz with buffer gas pressure of 75 Torr. For short pulse applications, the CVL is preferably operated at high PRR and low buffer gas regime. For the 25-W CVL used here, the prepulse electron density should be higher than 10 to the 13th/cu cm for efficient laser operation. The output power of this CVL can be increased to much higher than 30 W if the thermal insulation is optimized and the PRR is increased.

  4. Experimental study of flow and heat transfer in a rotating chemical vapor deposition reactor

    NASA Astrophysics Data System (ADS)

    Wong, Sun

    An experimental model was set up to study the rotating vertical impinging chemical vapor deposition reactor. Deposition occurs only when the system has enough thermal energy. Therefore, understanding the fluid characteristic and heat transfer of the system will provide a good basis to understand the full model. Growth rate and the uniformity of the film are the two most important factors in CVD process and it is depended on the flow and thermal characteristic within the system. Optimizing the operating parameters will result in better growth rate and uniformity. Operating parameters such as inflow velocity, inflow diameter and rotational speed are used to create different design simulations. Fluid velocities and various temperatures are recorded to see the effects of the different operating parameters. Velocities are recorded by using flow meter and hot wire anemometer. Temperatures are recorded by using various thermocouples and infrared thermometer. The result should provide a quantitative basis for the prediction, design and optimization of the system and process for design and fabrication of future CVD reactors. Further assessment of the system results will be discuss in detail such as effects of buoyancy and effects of rotation. The experimental study also coupled with a numerical study for further validation of both model. Comparisons between the two models are also presented.

  5. Determination of atmospheric temperature, water vapor, and heating rates from mid- and far- infrared hyperspectral measurements

    NASA Astrophysics Data System (ADS)

    Feldman, D.; Liou, K.; Yung, Y.; Johnson, D.; Mlynczak, M.

    2007-12-01

    Comprehensive satellite-borne far-infrared (15-100 μm) hyperspectral measurements of the earth have not been implemented since the short-lived Infrared Interferometer Sounder-D (IRIS-D) instrument on the Nimbus-4 satellite ceased operation in 1971 due primarily to instrumentation limitations and mission cost considerations. Recently, the development of the Far Infrared Spectroscopy of the Troposphere (FIRST) instrument [Mlynczak et al, 2006], a balloon-borne FTS which records spectra from 5 to 200 μm, provides a test-bed for the development of space-based far-infrared measurements for climate change monitoring. A comparison of the retrieval capabilities of a notional space-based instrument of comparable performance to FIRST and the currently-operational mid-infrared instrument AIRS is presented. Temperature and water vapor retrievals are compared (in an orbital simulation framework) along with the relative ability of the retrievals from these two instruments to constrain the heating rate profile. Also, the skill with which the AIRS measurements can be used to extrapolate the cloud radiative effect into the far-infrared is explored. Finally, FIRST test flight spectra are presented in the framework of other A-Train measurements such as MODIS and CALIPSO, followed by a discussion of climate applications.

  6. Biodecontamination of animal rooms and heat-sensitive equipment with vaporized hydrogen peroxide.

    PubMed

    Krause, J; McDonnell, G; Riedesel, H

    2001-11-01

    Common methods used to decontaminate and disinfect laboratory animal areas are difficult to standardize, labor-intensive, and potentially hazardous for staff members and the environment. As an alternative to traditional methods, we tested fumigation with vaporized hydrogen peroxide by using the VHP 1000 Biodecontamination System. The design of our air-conditioning system allowed the connection of the generator to any animal room by using the ventilation piping, thus forming a closed circuit. A 3-h cycle consisting of dehumidification, conditioning, sterilization, and aeration was developed and shown to be effective. The biodecontamination process was monitored during five independent trials using chemical and biological (Bacillus stearothermophilus spores) indicators. Contact plates for testing surfaces and room air for environmental bacteria, yeasts, and fungi consistently showed fewer than 10 colony-forming units per 100 cm2 or per 1 liter air. In addition, this method proved successful with heat-sensitive equipment like the blower units of individually ventilated caging systems. Overall, the system was easy to use and very effective in biodecontaminating animal rooms and equipment in a reproducible manner. There were no signs of corrosion or functional damage after more than 10 fumigation cycles. Work load and potential health risk for staff members and the environment was negligible.

  7. Simple Expressions to Predict Actual Performance of Vapor Compression Air-conditioner Concerning Heat Island Analysis

    NASA Astrophysics Data System (ADS)

    Shinomiya, Naruaki; Nishimura, Nobuya; Iyota, Hiroyuki

    Simple expressions to predict actual performance of vapor compression air-conditioners such as room air-conditioners and multi-split type air-conditioners are proposed. Coefficient of performance is expressed in these simple expressions as a function of outdoor temperature, indoor temperature, air-conditioning load rate, air flow rate of indoor unit (in case of room air-conditioners) and difference in height between indoor unit and outdoor unit (in case of multi-split type air-conditioners). Those simple expressions are obtained by neural net work analysis (Rule extraction method from facts, RF5). Actual performance of air-conditioners which are used for training data and teaching data of net work are obtained by numerical simulations developed by the authors. Calculation results of these simple expressions usually agree with experimental values of other researchers. Furthermore, amount of exhaust heat from air-conditioners calculated with these expressions are 10% or lower than traditional approach: calculated with constant value of coefficient of performance.

  8. The stability of Au-chloride complexes in water vapor at elevated temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Archibald, S. M.; Migdisov, A. A.; Williams-Jones, A. E.

    2001-12-01

    The solubility of gold in liquid-undersaturated HCl-bearing water vapor was investigated experimentally at temperatures of 300 to 360°C and pressures up to 144 bars. Results of these experiments show that the solubility of gold in the vapor phase is significant and increases with increasing fHCl and fH 2O . This behavior of gold is attributed to formation of hydrated gold-chloride gas species, interpreted to have a gold-chlorine ratio of 1:1 and a hydration number varying from 5 at 300°C to 3 at 360°C. These complexes are proposed to have formed through the following reaction: Ausolid+ m· HClgas+ n· H2Ogas= AuClm·( H2O) ngas+ m/2· H2gas which was determined to have log K values of -17.28 ± 0.36 at 300°C, -18.73 ± 0.66 at 340°C, and -18.74 ± 0.43 at 360°C. Gold solubility in the vapor was retrograde, i.e., it decreased with increasing temperature, possibly as a result of the inferred decrease in hydration number. Calculations based on our data indicate that at 300°C and fO 2-pH conditions, encountered in high sulfidation epithermal systems, the vapor phase can transport up to 6.6 ppb gold, which would be sufficient to form an economic deposit (e.g., Nansatsu, Japan; 36 tonnes) in ˜ 30,000 yr.

  9. Improvement of efficiency and temperature control of induction heating vapor source on electron cyclotron resonance ion source.

    PubMed

    Takenaka, T; Kiriyama, R; Muramatsu, M; Kitagawa, A; Uchida, T; Kurisu, Y; Nozaki, D; Yano, K; Yoshida, Y; Sato, F; Kato, Y; Iida, T

    2012-02-01

    An electron cyclotron resonance ion source (ECRIS) is used to generate multicharged ions for many kinds of the fields. We have developed an evaporator by using induction heating method that can generate pure vapor from solid state materials in ECRIS. We develop the new matching and protecting circuit by which we can precisely control the temperature of the induction heating evaporator. We can control the temperature within ±15 °C around 1400 °C under the operation pressure about 10(-4) Pa. We are able to use this evaporator for experiment of synthesizing process to need pure vapor under enough low pressure, e.g., experiment of generation of endohedral Fe-fullerene at the ECRIS.

  10. Improvement of efficiency and temperature control of induction heating vapor source on electron cyclotron resonance ion source

    SciTech Connect

    Takenaka, T.; Kiriyama, R.; Kurisu, Y.; Nozaki, D.; Yano, K.; Sato, F.; Kato, Y.; Iida, T.; Muramatsu, M.; Kitagawa, A.; Uchida, T.; Yoshida, Y.

    2012-02-15

    An electron cyclotron resonance ion source (ECRIS) is used to generate multicharged ions for many kinds of the fields. We have developed an evaporator by using induction heating method that can generate pure vapor from solid state materials in ECRIS. We develop the new matching and protecting circuit by which we can precisely control the temperature of the induction heating evaporator. We can control the temperature within {+-}15 deg. C around 1400 deg. C under the operation pressure about 10{sup -4} Pa. We are able to use this evaporator for experiment of synthesizing process to need pure vapor under enough low pressure, e.g., experiment of generation of endohedral Fe-fullerene at the ECRIS.

  11. Waste-Heat-Driven Cooling Using Complex Compound Sorbents

    NASA Technical Reports Server (NTRS)

    Rocketfeller, Uwe; Kirol, Lance; Khalili, Kaveh

    2004-01-01

    Improved complex-compound sorption pumps are undergoing development for use as prime movers in heat-pump systems for cooling and dehumidification of habitats for humans on the Moon and for residential and commercial cooling on Earth. Among the advantages of sorption heat-pump systems are that they contain no moving parts except for check valves and they can be driven by heat from diverse sources: examples include waste heat from generation of electric power, solar heat, or heat from combustion of natural gas. The use of complex compound sorbents in cooling cycles is not new in itself: Marketing of residential refrigerators using SrCl2 was attempted in the 1920s and 30s and was abandoned because heat- and mass-transfer rates of the sorbents were too low. Addressing the issue that gave rise to the prior abandonment of complex compound sorption heat pumps, the primary accomplishment of the present development program thus far has been the characterization of many candidate sorption media, leading to large increases in achievable heat- and mass-transfer rates. In particular, two complex compounds (called "CC260-1260" and "CC260-2000") were found to be capable of functioning over the temperature range of interest for the lunar-habitat application and to offer heat- and mass-transfer rates and a temperature-lift capability adequate for that application. Regarding the temperature range: A heat pump based on either of these compounds is capable of providing a 95-K lift from a habitable temperature to a heat-rejection (radiator) temperature when driven by waste heat at an input temperature .500 K. Regarding the heat- and mass-transfer rates or, more precisely, the power densities made possible by these rates: Power densities observed in tests were 0.3 kilowatt of cooling per kilogram of sorbent and 2 kilowatts of heating per kilogram of sorbent. A prototype 1-kilowatt heat pump based on CC260-2000 has been built and demonstrated to function successfully.

  12. Heat and Mass Transfer in the Chemical Vapor Deposition of Silicon Carbide in a Porous Carbon-Carbon Composite Material for a Heat Shield

    NASA Astrophysics Data System (ADS)

    Reznik, S. V.; Mikhailovskii, K. V.; Prosuntsov, P. V.

    2017-03-01

    Physical and mathematical simulations of the chemical vapor deposition of silicon carbide in a porous carbon-carbon composite material in a chemical vapor deposition reactor for formation of a matrix of a carbon-ceramic composite material for a heat shield of an aerospace aircraft have been performed. Results of parametric calculations of the heat and mass transfer at the macro- and microlevels in representative elements of the microstructure of carbon-carbon composite materials different in residual porosity at different temperatures in the reaction zone of the reactor are presented. Features of compaction of the pore space of a carbon-carbon composite material by a silicon-carbide matrix depending on the technological parameters of the reaction medium were analyzed.

  13. Quantifying Heat Flow from a Restless Caldera: Shallow Measurement from a Vapor Dominated Area of the Yellowstone Plateau Volcanic Field

    NASA Astrophysics Data System (ADS)

    Rosenberg, R.; Harris, R. N.; Hurwitz, S.; Fulton, P. M.; Davis, M. G.; Werner, C. A.

    2009-12-01

    Any attempt to characterize the vigor of magmatic activity and forecast future volcanism in Yellowstone caldera requires knowledge regarding the thermal state of its magmatic system, one of the largest and most focused heat sources on Earth. Current knowledge of heat transport between magma and the ground surface is limited. Advective heat transport from the caldera has been quantified by measuring chloride flux from the major rivers draining the caldera, based on the assumptions of the chloride inventory method (Fournier, JVGR1979). We have quantified the total (conductive, advective, and evaporative) heat flux from one of the most active thermal areas in Yellowstone caldera, the Obsidian Pool thermal area (OPTA) which includes 0.1 km2 of thermal ground within the Mud Volcano thermal area. The OPTA is characterized by vapor dominated conditions. Rising steam and other gases (mainly CO2) fill open fractures beneath a low-permeability cap consisting of clay minerals (Bargar and Muffler, 1982). Conduction-dominated heat transfer through the clay cap is associated with a high temperature gradient. We made at least 4 soil-temperature measurements at 0-1 m depth at 251 locations in the OPTA and measured soil thermal conductivity in the laboratory. Evaporative heat from several thermal pools was quantified based on pool temperatures and meteorological data. Our preliminary analysis indicates that surface heat loss from OPTA is dominantly conductive. Extrapolation of the OPTA results to approximately 35 km2 of vapor-dominated area in Yellowstone caldera and surroundings would yield a total heat flow that constitutes a major fraction of the total heat power from Yellowstone’s magmatic system.

  14. Effect of heat-treatment temperature of vapor-grown graphite fibers. I - Properties of their bromine intercalation compounds

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Hambourger, Paul D.; Slabe, Melissa E.

    1989-01-01

    Vapor-grown graphite fibers were heat treated at 2000, 2200, 2400, 2600, 2800, and 3000 C, brominated at room temperature for two days, and then characterized by X-ray diffraction analysis, differential scanning calorimetry, and resistivity measurements. Fibers greater than 13 microns in diameter had low resistivities (50 microohms or less) irrespective of the heat treatment temperature. An analysis of the results obtained suggests that resistivities below 6 microohms cannot be achieved through a further reduction in defect level unless the amount of bromine is increased.

  15. Effect of heat-treatment temperature of vapor-grown graphite fibers. I - Properties of their bromine intercalation compounds

    NASA Technical Reports Server (NTRS)

    Gaier, James R.; Hambourger, Paul D.; Slabe, Melissa E.

    1989-01-01

    Vapor-grown graphite fibers were heat treated at 2000, 2200, 2400, 2600, 2800, and 3000 C, brominated at room temperature for two days, and then characterized by X-ray diffraction analysis, differential scanning calorimetry, and resistivity measurements. Fibers greater than 13 microns in diameter had low resistivities (50 microohms or less) irrespective of the heat treatment temperature. An analysis of the results obtained suggests that resistivities below 6 microohms cannot be achieved through a further reduction in defect level unless the amount of bromine is increased.

  16. Vapor-modulated heat pipe report. Flight data analysis and further development of variable-conductance heat pipes. [design analysis and performance tests

    NASA Technical Reports Server (NTRS)

    Eninger, J. E.; Fleischman, G. L.; Luedke, E. E.

    1975-01-01

    The design and testing of a heat pipe for spacecraft application is presented. The application in mind calls for heat loads up to 20 watts, a set-point temperature of 294K, and a sink that varies from -220K to nearly as high as the set-point. The overall heat pipe length is 137 cm. Two basically different mechanisms of achieving variable conductance in the pipe by vapor-flow throttling were studied. In one, the thermal resistance between the heat source and sink is due to a saturation-temperature drop corresponding to the vapor-pressure drop developed across the valve. In the other, the pressure difference across the valve induces capillary groove and wick dry out in an evaporation region, and thus results in an increased thermal resistance. This mechanism was selected for fabrication and testing. The pipe is a stainless-steel/methanol two-heat-pipe system. Results are presented and discussed. Engineering drawings and specifications of the pipe are shown.

  17. Exploring the Relationship Between Octane Sensitivity and Heat-of-Vaporization

    SciTech Connect

    Sluder, C. Scott; Szybist, James P.; McCormick, Robert L.; Ratcliff, Matthew A.; Zigler, Bradley T.

    2016-04-05

    The latent heat-of-vaporization (HoV) of blends of biofuel and hydrocarbon components into gasolines has recently experienced expanded interest because of the potential for increased HoV to increase fuel knock resistance in direct-injection (DI) engines. Several studies have been conducted, with some studies identifying an additional anti-knock benefit from HoV and others failing to arrive at the same conclusion. Consideration of these studies holistically shows that they can be grouped according to the level of fuel octane sensitivity variation within their fuel matrices. When comparing fuels of different octane sensitivity significant additional anti-knock benefits associated with HoV are sometimes observed. Studies that fix the octane sensitivity find that HoV does not produce additional anti-knock benefit. New studies were performed at ORNL and NREL to further investigate the relationship between HoV and octane sensitivity. Three fuels were formulated for the ORNL study with matched RON and octane sensitivity, but with differing HoV. Experiments with these fuels in a 1.6-liter GTDI engine showed that the fuels exhibited very similar combustion phasing under knock-limited spark advance (KLSA) conditions. Fuels having a range of RON, octane sensitivity, and HoV were tested at NREL in a single-cylinder GDI engine under conditions where octane sensitivity has little effect on knock resistance. KLSA was found to be well correlated with RON. These results reinforce the concept that HoV anti-knock effects can be viewed as a contributor to octane sensitivity. From this viewpoint, HoV effects manifest themselves as increases in octane sensitivity.

  18. Simple analysis of total mercury and methylmercury in seafood using heating vaporization atomic absorption spectrometry.

    PubMed

    Yoshimoto, Keisuke; Anh, Hoang Thi Van; Yamamoto, Atsushi; Koriyama, Chihaya; Ishibashi, Yasuhiro; Tabata, Masaaki; Nakano, Atsuhiro; Yamamoto, Megumi

    2016-01-01

    This study aimed to develop a simpler method for determining total mercury (T-Hg) and methylmercury (MeHg) in biological samples by using methyl isobutyl ketone (MIBK) in the degreasing step. The fat in the samples was extracted by MIBK to the upper phase. T-Hg transferred into the water phase. This was followed by the extraction of MeHg from the water phase using HBr, CuCl2 and toluene. The MeHg fraction was reverse-extracted into L-cysteine-sodium acetate solution from toluene. The concentrations of T-Hg and MeHg were determined by heating vaporization atomic absorption spectrometry. Certified reference materials for T-Hg and MeHg in hair and fish were accurately measured using this method. This method was then applied to determine T-Hg and MeHg concentrations in the muscle, liver and gonads of seafood for the risk assessment of MeHg exposure. The mean T-Hg and MeHg concentrations in squid eggs were 0.023 and 0.022 µg/g, and in squid nidamental glands 0.052 and 0.049 µg/g, respectively. The MeHg/T-Hg ratios in the eggs and nidamental glands of squid were 94.4% and 96.5%, respectively. The mean T-Hg and MeHg concentrations in the gonads of sea urchins were 0.043 and 0.001 µg/g, respectively, with a MeHg/T-Hg ratio of 3.5%. We developed an efficient analytical method for T-Hg and MeHg using MIBK in the degreasing step. The new information on MeHg concentration and MeHg/T-Hg ratios in the egg or nidamental glands of squid and gonads of sea urchin will also be useful for risk assessment of mercury in seafood.

  19. Large-eddy Simulation of Heat and Water Vapor Transfer in CT-Based Human Airway Models

    NASA Astrophysics Data System (ADS)

    Wu, Dan; Tawhai, Merryn; Hoffman, Eric; Lin, Ching-Long

    2014-11-01

    We propose a novel imaging-based thermodynamic model to study local heat and mass transfers in the human airways. Both 3D and 1D CFD models are developed and validated. Large-eddy simulation (LES) is adopted to solve 3D incompressible Navier-Stokes equations with Boussinesq approximation along with temperature and water vapor transport equations and energy-flux based wall boundary condition. The 1D model provides initial and boundary conditions to the 3D model. The computed tomography (CT) lung images of three healthy subjects with sinusoidal waveforms and minute ventilations of 6, 15 and 30 L/min are considered. Between 1D and 3D models and between subjects, the average temperature and water vapor distributions are similar, but their regional distributions are significantly different. In particular, unlike the 1D model, the heat and water vapor transfers in the 3D model are elevated at the bifurcations during inspiration. Moreover, the correlations of Nusselt number (Nu) and Sherwood number (Sh) with local Reynolds number and airway diameter are proposed. In conclusion, use of the subject-specific lung model is essential for accurate prediction of local thermal impacts on airway epithelium. Supported in part by NIH grants R01-HL094315, U01-HL114494 and S10-RR022421.

  20. Characteristics of a High Intensity, Pulsed, Potassium Vapor Laser in a Heat Pipe

    DTIC Science & Technology

    2011-03-01

    metals form the first column of the periodic table. From the top, this column includes lithium, sodium , potassium, rubidium, and cesium . They...pumped rubidium vapor laser by Krupke [2]. Since then, cesium (Cs), rubidium (Rb), and potassium (K) vapor lasers have been demonstrated and are the...would degrade the population inversion necessary for lasing to occur. Fortunately, the cesium and rubidium DPALs have much greater spin-orbit

  1. Effects of Vegetation and of Heat and Vapor Fluxes from Soil on Snowpack Evolution and Radiobrightness

    NASA Technical Reports Server (NTRS)

    Chung, Y. C.; England, A. W.; DeRoo, R. D.; Weininger, Etai

    2006-01-01

    The radiobrightness of a snowpack is strongly linked to the snow moisture content profile, to the point that the only operational inversion algorithms require dry snow. Forward dynamic models do not include the effects of freezing and thawing of the soil beneath the snowpack and the effect of vegetation within the snow or above the snow. To get a more realistic description of the evolution of the snowpack, we reported an addition to the Snow-Soil-Vegetation-Atmosphere- Transfer (SSVAT) model, wherein we coupled soil processes of the Land Surface Process (LSP) model with the snow model SNTHERM. In the near future we will be adding a radiobrightness prediction based on the modeled moisture, temperature and snow grain size profiles. The initial investigations with this SSVAT for a late winter and early spring snow pack indicate that soil processes warm the snowpack and the soil. Vapor diffusion needs to be considered whenever the ground is thawed. In the early spring, heat flow from the ground into a snow and a strong temperature gradient across the snow lead to thermal convection. The buried vegetation can be ignored for a late winter snow pack. The warmer surface snow temperature will affect radiobrightness since it is most sensitive to snow surface characteristics. Comparison to data shows that SSVAT provides a more realistic representation of the temperature and moisture profiles in the snowpack and its underlying soil than SNTHERM. The radiobrightness module will be optimized for the prediction of brightness when the snow is moist. The liquid water content of snow causes considerable absorption compared to dry snow, and so longer wavelengths are likely to be most revealing as to the state of a moist snowpack. For volumetric moisture contents below about 7% (the pendular regime), the water forms rings around the contact points between snow grains. Electrostatic modeling of these pendular rings shows that the absorption of these rings is significantly higher than a

  2. Sahara Heat Low Perturbations and Water Vapor in the Sahel: A Positive Feedback System

    NASA Astrophysics Data System (ADS)

    Caughman, L.; Evan, A. T.

    2013-12-01

    It is necessary to understand the drivers and feedbacks of global desertification, motivated by the increasing need to improve global food production and to sustainably manage ecosystems in the context of climate change. Climate change and land dynamics are the perturbations that are major drivers of an ecosystem shift to a ';';desertified'' state. This shift is typically sustained by positive feedbacks, which stabilize the system in the new state. This research focuses on changes in precipitation resulting from land-atmosphere interactions and changes in vegetation cover. We concentrate on the Sahel region of Africa (a strip of land that is a transitional area between the Sahara desert to the North and the rain forest to the South). It is a dry land, semi arid environment and is a bistable ecosystem that can either be in the state of 'dry' or 'wet'. After an abnormally wet/high precipitation period in the 1950s the Sahel experienced terrible droughts and desertification which peaked in the 1980s. Since then, precipitation has gradually increased and a sinusoidal model has been shown run on a multi decadal cycle. Discrepancies in the data exist, however, and although the overall cycle has been modeled well, the large inter-annual fluctuations in precipitation have yet to be sufficiently modeled or explained. This research offers new evidence as to why such a phenomenon exists and attempts to attribute this behavior to a coupled land-atmosphere feedback system, linking together changes in vegetation cover and precipitation in the Sahel. Using the model output data from a high resolution Weather Research and Forecasting (WRF) model to look at Africa and compare the difference between perturbations and the mean, this research asserts that when the surface of the Saharan Heat Low (SHL) becomes extremely hot the pressure drops substantially. Subsequently, due to the West African Monsoon system, air rushes in from high-pressure areas, and pulls monsoon precipitation

  3. Effects of Vegetation and of Heat and Vapor Fluxes from Soil on Snowpack Evolution and Radiobrightness

    NASA Technical Reports Server (NTRS)

    Chung, Y. C.; England, A. W.; DeRoo, R. D.; Weininger, Etai

    2006-01-01

    The radiobrightness of a snowpack is strongly linked to the snow moisture content profile, to the point that the only operational inversion algorithms require dry snow. Forward dynamic models do not include the effects of freezing and thawing of the soil beneath the snowpack and the effect of vegetation within the snow or above the snow. To get a more realistic description of the evolution of the snowpack, we reported an addition to the Snow-Soil-Vegetation-Atmosphere- Transfer (SSVAT) model, wherein we coupled soil processes of the Land Surface Process (LSP) model with the snow model SNTHERM. In the near future we will be adding a radiobrightness prediction based on the modeled moisture, temperature and snow grain size profiles. The initial investigations with this SSVAT for a late winter and early spring snow pack indicate that soil processes warm the snowpack and the soil. Vapor diffusion needs to be considered whenever the ground is thawed. In the early spring, heat flow from the ground into a snow and a strong temperature gradient across the snow lead to thermal convection. The buried vegetation can be ignored for a late winter snow pack. The warmer surface snow temperature will affect radiobrightness since it is most sensitive to snow surface characteristics. Comparison to data shows that SSVAT provides a more realistic representation of the temperature and moisture profiles in the snowpack and its underlying soil than SNTHERM. The radiobrightness module will be optimized for the prediction of brightness when the snow is moist. The liquid water content of snow causes considerable absorption compared to dry snow, and so longer wavelengths are likely to be most revealing as to the state of a moist snowpack. For volumetric moisture contents below about 7% (the pendular regime), the water forms rings around the contact points between snow grains. Electrostatic modeling of these pendular rings shows that the absorption of these rings is significantly higher than a

  4. Differential heat of adsorption of water vapor on silicified microcrystalline cellulose (SMCC): an investigation using isothermal microcalorimetry.

    PubMed

    Qian, Ken K; Bogner, Robin H

    2011-01-01

    A novel dual-shaft configuration in isothermal microcalorimetry was developed to study the interaction of water vapor with pharmaceutical excipients. An instrument performance test is suggested to validate the experimental data. Reliable experimental results can be collected using a single perfusion shaft; however, there was limitation of the dual-shaft configuration, which resulted deviation in the experimental results. A periodic performance test is recommended. Silicified microcrystalline cellulose (SMCC) was used as a model system to study the interaction using the dual-shaft method. Enthalpy of water vapor adsorption on SMCC was determined and compared to literature data. The data collected using the dual-shaft configuration did not reflect the actual physical system. The deviation was most likely due to the lack of flow control caused by viscous resistance. The enthalpy of adsorption was then calculated using isothermal microcalorimetry coupled with a dynamic vapor sorption apparatus. The results, -55 kJ/mol at low relative humidity (RH) to -22 kJ/mol at high RH, were consistent with the physical phenomenon of water vapor adsorption. Enthalpy of adsorption showed surface heterogeneity of SMCC and suggested multilayer condensation of water at approximately 60% RH. However, at high RH, the results showed the moisture-excipient interaction can be more complex than the proposed mechanism.

  5. Operation characteristic of a heat pump of mechanical vapor recompression propelled by fans and its performance analysis applied to waste-water treatment

    NASA Astrophysics Data System (ADS)

    Weike, Pang; Wenju, Lin; Qilin, Pan; Wenye, Lin; Qunte, Dai; Luwei, Yang; Zhentao, Zhang

    2014-01-01

    In this paper, a set of heat pump (called as Mechanical Vapor Recompression, MVR) propelled by a centrifugal fan is tested and it shows some special characteristic when it works together with a falling film evaporator. Firstly, an analysis of the fan's suction and discharge parameters at stable state, such as its pressure and temperature, indicates that a phenomenon of wet compression is probably to appear during vapor compression. As a result, superheat after saturated vapor is compressed is eliminated, which reduces discharge temperature of the system. It is because drops boil away and absorb the super heat into their latent heat during vapor compression. Meanwhile, drops in the suction vapor add to the compressed vapor, which increase the given heat of the MVR heat pump. Next, assistant electric heat could adjust and keep steady of the operating pressure and temperature of an MVR heat pump. With the evaporation temperature up to be high, heat balance is broken and supplement heat needs to increase. Thirdly, the performance of an MVR heat pump is affect by the balance of falling film and evaporation that has an effect on heat transfer. Then, two parameters standing for the performance are measured as it runs in practical condition. The two important parameters are consumptive electricity power and productive water capacity. According to theoretical work in ideal condition by calculation and fan's input power by measure as running, adiabatic efficiency (ηad) of a centrifugal fan is calculated when it is applied in a heat pump of MVR. Following, based on ηad, practical SMER and COP of an MVR heat pump are discovered to be correlative with it. Finally, in dependence on productive water in theory and in practice, displacement efficiency (ηv) of centrifugal fans is obtained when compressing vapor, and so provide some references of matching a fan for an MVR heat pump. On the other hand, it is helpful to research and develop MVR heat pumps, and also to check

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

    PubMed

    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.

  7. Spectrophotometric studies of holmium(III) chloride-aluminum(III) chloride vapor complexes

    SciTech Connect

    Williams, C.W.; Hessler, J.P.; Peterson, E.J.

    1980-01-01

    The gas complexation reactions between LnCl/sub 3/ and Al/sub 2/Cl/sub 6/ to yield molecular species of the form LnCl/sub 3/ (Al/sub 2/Cl/sub 6/)/sub x/ have been studied for a number of years. The spectrophotometric technique has been used to deduce the thermodynamic properties of the molecular species. We have studied the HoCl/sub 3/ (Al/sub 2/Cl/sub 6/)/sub x/ system from 600 to 900/sup 0/K and at Al/sub 2/Cl/sub 6/ pressures between 1 and 7 atm. The Ho/sup 3 +/ hypersensitive transition between /sup 5/I/sub 8/ and /sup 5/G/sub 6/ at 456 nm has been used to measure the complex vapor densities as a function of pressure and temperature. A temperature-dependence of the optical absorption spectrum was observed in samples with a constant Ho/sup 3 +/ ion density. These data cannot be understood in terms of the generally used treatment of molar absorptivity, but requires the introduction of an effective oscillator strength. A temperature-dependent oscillator effect is also observed and this is interpeted as evidence for the presence of multiple species with differing oscillator strengths. The consequence of these observations for the determination of equilibrium constants for the different species will be discussed.

  8. Revealing the complex conduction heat transfer mechanism of nanofluids.

    PubMed

    Sergis, A; Hardalupas, Y

    2015-12-01

    Nanofluids are two-phase mixtures consisting of small percentages of nanoparticles (sub 1-10 %vol) inside a carrier fluid. The typical size of nanoparticles is less than 100 nm. These fluids have been exhibiting experimentally a significant increase of thermal performance compared to the corresponding carrier fluids, which cannot be explained using the classical thermodynamic theory. This study deciphers the thermal heat transfer mechanism for the conductive heat transfer mode via a molecular dynamics simulation code. The current findings are the first of their kind and conflict with the proposed theories for heat transfer propagation through micron-sized slurries and pure matter. The authors provide evidence of a complex new type of heat transfer mechanism, which explains the observed abnormal heat transfer augmentation. The new mechanism appears to unite a number of popular speculations for the thermal heat transfer mechanism employed by nanofluids as predicted by the majority of the researchers of the field into a single one. The constituents of the increased diffusivity of the nanoparticle can be attributed to mismatching of the local temperature profiles between parts of the surface of the solid and the fluid resulting in increased local thermophoretic effects. These effects affect the region surrounding the solid manifesting interfacial layer phenomena (Kapitza resistance). In this region, the activity of the fluid and the interactions between the fluid and the nanoparticle are elevated. Isotropic increased nanoparticle mobility is manifested as enhanced Brownian motion and diffusion effects.

  9. Revealing the complex conduction heat transfer mechanism of nanofluids

    NASA Astrophysics Data System (ADS)

    Sergis, A.; Hardalupas, Y.

    2015-06-01

    Nanofluids are two-phase mixtures consisting of small percentages of nanoparticles (sub 1-10 %vol) inside a carrier fluid. The typical size of nanoparticles is less than 100 nm. These fluids have been exhibiting experimentally a significant increase of thermal performance compared to the corresponding carrier fluids, which cannot be explained using the classical thermodynamic theory. This study deciphers the thermal heat transfer mechanism for the conductive heat transfer mode via a molecular dynamics simulation code. The current findings are the first of their kind and conflict with the proposed theories for heat transfer propagation through micron-sized slurries and pure matter. The authors provide evidence of a complex new type of heat transfer mechanism, which explains the observed abnormal heat transfer augmentation. The new mechanism appears to unite a number of popular speculations for the thermal heat transfer mechanism employed by nanofluids as predicted by the majority of the researchers of the field into a single one. The constituents of the increased diffusivity of the nanoparticle can be attributed to mismatching of the local temperature profiles between parts of the surface of the solid and the fluid resulting in increased local thermophoretic effects. These effects affect the region surrounding the solid manifesting interfacial layer phenomena (Kapitza resistance). In this region, the activity of the fluid and the interactions between the fluid and the nanoparticle are elevated. Isotropic increased nanoparticle mobility is manifested as enhanced Brownian motion and diffusion effects

  10. GAM-HEAT: A computer code to compute heat transfer in complex enclosures. Revision 2

    SciTech Connect

    Cooper, R.E.; Taylor, J.R.

    1992-12-01

    This report discusses the GAM{underscore}HEAT code which was developed for heat transfer analyses associated with postulated Double Ended Guilliotine Break Loss Of Coolant Accidents (DEGB LOCA) resulting in a drained reactor vessel. In these analyses the gamma radiation resulting from fission product decay constitutes the primary source of energy as a function of time. This energy is deposited into the various reactor components and is re-radiated as thermal energy. The code accounts for all radiant heat exchanges within and leaving the reactor enclosure. The SRS reactors constitute complex radiant exchange enclosures since there are many assemblies of various types within the primary enclosure and most of the assemblies themselves constitute enclosures. GAM-HEAT accounts for this complexity by processing externally generated view factors and connectivity matrices as discussed below, and also accounts for convective, conductive, and advective heat exchanges. The code is structured such that it is applicable for many situations involving heat exchange between surfaces within a radiatively passive medium.

  11. GAM-HEAT: A computer code to compute heat transfer in complex enclosures

    SciTech Connect

    Cooper, R.E.; Taylor, J.R.

    1992-12-01

    This report discusses the GAM[underscore]HEAT code which was developed for heat transfer analyses associated with postulated Double Ended Guilliotine Break Loss Of Coolant Accidents (DEGB LOCA) resulting in a drained reactor vessel. In these analyses the gamma radiation resulting from fission product decay constitutes the primary source of energy as a function of time. This energy is deposited into the various reactor components and is re-radiated as thermal energy. The code accounts for all radiant heat exchanges within and leaving the reactor enclosure. The SRS reactors constitute complex radiant exchange enclosures since there are many assemblies of various types within the primary enclosure and most of the assemblies themselves constitute enclosures. GAM-HEAT accounts for this complexity by processing externally generated view factors and connectivity matrices as discussed below, and also accounts for convective, conductive, and advective heat exchanges. The code is structured such that it is applicable for many situations involving heat exchange between surfaces within a radiatively passive medium.

  12. Micrometeorological observations of carbon, water vapor and heat exchanges on the California Academy of Sciences' living roof using eddy covariance

    NASA Astrophysics Data System (ADS)

    Lavender, S.; Oliphant, A. J.; Thorp, R.

    2014-12-01

    Living roofs have very different surface energy, water and carbon budgets than conventional roofs. Since roofs cover approximately one third of the planimetric surface area of cities, they are a significant driver of the urban boundary layer. Living roofs have been thought to be beneficial for reducing the urban heat island through increased latent heat exchange, uptake of atmospheric carbon dioxide and storage in soil and plant matter, building energy conservation through soil heat storage and latent heat fluxes and reduction in runoff. Here we present evidence of some of these through ongoing observations of surface energy, water and carbon budget estimates for the extensive living roof of the California Academy of Sciences building in Golden Gate Park, San Francisco, California. Micrometeorological measurements including the eddy covariance approach are used to estimate CO2, water vapor and both ground and atmospheric heat fluxes. The California Academy's roof encompasses an area of 18,000 m2. Vegetation surveys were conducted in the spring; beach strawberry (Fragaria chiloensis) and California bentgrass (Agrostis) were found to dominate the project footprint out of the 26 species observed. Eddy covariance measurements are made about one meter above the 10-20 cm tall vegetation on the downwind side of the building. Approximately 50% of data are rejected due to less than 80% of the flux source area being contained in the roof or due to low friction velocity. Nevertheless, we are able to develop robust diurnal ensemble fluxes, and will present data from a nine month period. During summer, the roof acted as a carbon sink of approximately 1.5 gC m-2 d-1. Turbulent heat fluxes were dominated by sensible heat flux with a mean Bowen ratio of approximately 1.5 and daily evapotranspiration rates of about 1.8 mm d-1. The role of seasonality and meteorology on surface microclimate characteristics will also be discussed.

  13. The mechanical design of a vapor compressor for a heat pump to be used in space

    NASA Technical Reports Server (NTRS)

    Berner, F.; Oesch, H.; Goetz, K.; Savage, C. J.

    1982-01-01

    A heat pump developed for use in Spacelab as a stand-alone refrigeration unit as well as within a fluid loop system is discussed. It will provide an active thermal control for payloads. Specifications for the heat pump were established: (1) heat removal rates at the source; (2) heat source temperatures from room temperature; (3) heat-sink fluid temperatures at condenser inlet; and (4) minimum power consumption. A reversed Carnot cycle heat pump using Freon 12 as working fluid incorporating a one-cylinder reciprocating compressor was selected. The maximum crankshaft speed was fixed relatively high at 100 rpm. The specified cooling rates then made it necessary to select a cylinder volume of 10 cu cm, which was obtained with a bore of 40 mm and a stroke of 8 mm.

  14. GAM-HEAT -- a computer code to compute heat transfer in complex enclosures. Revision 1

    SciTech Connect

    Cooper, R.E.; Taylor, J.R.; Kielpinski, A.L.; Steimke, J.L.

    1991-02-01

    The GAM-HEAT code was developed for heat transfer analyses associated with postulated Double Ended Guillotine Break Loss Of Coolant Accidents (DEGB LOCA) resulting in a drained reactor vessel. In these analyses the gamma radiation resulting from fission product decay constitutes the primary source of energy as a function of time. This energy is deposited into the various reactor components and is re- radiated as thermal energy. The code accounts for all radiant heat exchanges within and leaving the reactor enclosure. The SRS reactors constitute complex radiant exchange enclosures since there are many assemblies of various types within the primary enclosure and most of the assemblies themselves constitute enclosures. GAM-HEAT accounts for this complexity by processing externally generated view factors and connectivity matrices, and also accounts for convective, conductive, and advective heat exchanges. The code is applicable for many situations involving heat exchange between surfaces within a radiatively passive medium. The GAM-HEAT code has been exercised extensively for computing transient temperatures in SRS reactors with specific charges and control components. Results from these computations have been used to establish the need for and to evaluate hardware modifications designed to mitigate results of postulated accident scenarios, and to assist in the specification of safe reactor operating power limits. The code utilizes temperature dependence on material properties. The efficiency of the code has been enhanced by the use of an iterative equation solver. Verification of the code to date consists of comparisons with parallel efforts at Los Alamos National Laboratory and with similar efforts at Westinghouse Science and Technology Center in Pittsburgh, PA, and benchmarked using problems with known analytical or iterated solutions. All comparisons and tests yield results that indicate the GAM-HEAT code performs as intended.

  15. Heat-Pipe Bismuth Laser; Examination of Laser Action at 4722A in Bismuth Vapor

    DTIC Science & Technology

    1976-11-01

    Terminating Laser Transitions in Calcium and Strontium. " IEEE J. Quantum Electron. QE-4, 474 (1968). 7. P.Cahuzac, "Raies Laser Infrarouges dans les Vapeurs... Spectroscopy 19. 282(1065). 13. P.A. Rice and D. V. Ragone, "Simultaneous Determination of f Values and Vapor Pressures from Optical Absorption Measurements...approaching 10%6. Beam foil spectroscopy can be included with these more accurate methods if one can be certain that there is no unrecognized

  16. Effect of Wool Components in Pile Fabrics on Water Vapor Sorption, Heat Release, and Humidity Buffering

    DTIC Science & Technology

    2008-05-01

    recognized in the commercial marketplace . Experimental measurements of the water vapor sorption phenomena associated with these modifications to fabric...clothing. For example there are wool/Nomex blends that are of interest, as well as new variations on wool fibers such as enzyme -treated wool fabrics... enzyme -scoured wool fibers sufficiently flame-retardant to be used in thermally- protective military outerwear, or are more traditional Wool/Nomex

  17. Visualization Of Water Vaporization During Electrical Heating Process With X-ray Tomography

    NASA Astrophysics Data System (ADS)

    Wang, Jie; Li, Yubin; Erath, Michael; Kantzas, Apostolos

    2007-06-01

    This paper deals with the study of electrical heating as a potential method for recovery of heavy oil and bitumen from unconsolidated sand formations of Northern Alberta. Electrical heating is a preferred energy transfer method for heating relatively shallow formations containing bitumen with limited support for high-pressure steam injection. Simulation results demonstrated that although electrical heating can contribute to the recovery of oil, substantially more oil would be recovered if the formation or injected water were allowed to boil. Thus the in-situ steam creation has been the target of simulation and experimental work presented here.

  18. User's manual for the TRW gaspipe 2 program: A vapor-gas front analysis program for heat pipes containing non-condensible gas

    NASA Technical Reports Server (NTRS)

    Edwards, D. K.; Fleischman, G. L.; Marcus, B. D.

    1973-01-01

    A digital computer program for design and analysis of heat pipes which contain non-condensible gases, either for temperature control or to aid in start-up from the frozen state, is presented. Some of the calculations which are possible with the program are: (1) wall temperature profile along a gas-loaded heat pipe, (2) amount of gas loading necessary to obtain desired evaporator temperature at a desired heat load, (3) heat load versus evaporator temperature for a fixed amount of gas in the pipe, and (4) heat and mass transfer along the pipe, including the vapor-gas front region.

  19. Control of complex heat transfer on producing extremal fields

    NASA Astrophysics Data System (ADS)

    Grenkin, G. V.; Chebotarev, A. Yu.

    2016-10-01

    A time-dependent model of complex heat transfer including the P 1 approximation for the equation of radiative transfer is considered. The problem of finding the coefficient in the boundary condition from a given interval, providing the minimum (maximum) temperature and radiation intensity in the entire domain is formulated. The solvability of the control problem is proven, conditions for optimality are obtained, and an iterative algorithm for finding the optimal control is found.

  20. Synthesis of New Ba Complex as Metalorganic Source for Metalorganic Chemical Vapor Deposition and Optimization of Its Molecule Structure

    NASA Astrophysics Data System (ADS)

    Zama, Hideaki; Morishita, Tadataka

    2000-10-01

    New Ba(DPM)2-amine (DPM=dipivaloylmethane) adduct compounds were attempted to be synthesized from Ba(DPM)2 and amines. Complexes obtained were evaluated based on decreases of their weight with increasing temperature by thermogravimetry. The simple vaporizing phenomenon, showing a one-step weight-reduction curve, was observed only in the case of using tetraethylenepentamine and pentaethylenehexamine (pentaen) as adduct molecules, which have a simple chain structure and five to six primary and secondary amine radicals. From the viewpoint of applicability to film growth, they have the best structure based on a survey in this study using sixteen amine molecules with distinctive structures. When we used Ba(DPM)2-pentaen as a metalorganic source for a metalorganic chemical vapor deposition method at a vaporizing temperature of 140°C, the Ba supply rate remained stable within a standard deviation of 1.6% for over 300 h.

  1. Development of a reverse-Rankine cycle heat pump for space use: Design and testing of the engineering model of the vapor compressor

    NASA Astrophysics Data System (ADS)

    Berner, F.; Oesch, H.; Goetz, K.

    1981-09-01

    An installation for testing a vapor compressor under operating conditions in a heat pump loop, and the testing of the vapor compressor in this installation are described. The installation is a closed freon 12 loop, like that of a reverse Rankine cycle heat pump. It is demonstrated that the compressor operates satisfactorily under the most extreme conditions, including ingestion of liquid refrigerant during high speed operation, and operation of the compressor in different attitudes. It is shown that volumetric efficiency and isentropic compression efficiency are practically dependent on the compression ratio only, and are rather high for this size of compressor. A heat pump incorporating the vapor compressor cools payloads down to -40C. Maximum cooling rate is over 400W when payload temperature is 10C. Compressor power consumption never exceeds 120W.

  2. Unraveling the complex chemistry using dimethylsilane as a precursor gas in hot wire chemical vapor deposition.

    PubMed

    Toukabri, Rim; Shi, Yujun

    2014-05-07

    The gas-phase reaction chemistry when using dimethylsilane (DMS) as a source gas in a hot-wire chemical vapor deposition (CVD) process has been studied in this work. The complex chemistry is unraveled by using a soft 10.5 eV single photon ionization technique coupled with time-of-flight mass spectrometry in combination with the isotope labelling and chemical trapping methods. It has been demonstrated that both free-radical reactions and those involving silylene/silene intermediates are important. The reaction chemistry is characterized by the formation of 1,1,2,2-tetramethyldisilane (TMDS) from dimethylsilylene insertion into the Si-H bond of DMS, trimethylsilane (TriMS) from free-radical recombination, and 1,3-dimethyl-1,3-disilacyclobutane (DMDSCB) from the self dimerization of either dimethylsilylene or 1-methylsilene. At low filament temperatures and short reaction time, silylene chemistry dominates. The free-radical reactions become more important with increasing temperature and time. The same three products have been detected when using tantalum and tungsten filaments, indicating that changing the filament material from Ta to W does not affect much the gas-phase reaction chemistry when using DMS as a source gas in a hot-wire CVD reactor.

  3. A novel pre-oxidation method for elemental mercury removal utilizing a complex vaporized absorbent.

    PubMed

    Zhao, Yi; Hao, Runlong; Guo, Qing

    2014-09-15

    A novel semi-dry integrative method for elemental mercury (Hg(0)) removal has been proposed in this paper, in which Hg(0) was initially pre-oxidized by a vaporized liquid-phase complex absorbent (LCA) composed of a Fenton reagent, peracetic acid (CH3COOOH) and sodium chloride (NaCl), after which Hg(2+) was absorbed by the resultant Ca(OH)2. The experimental results indicated that CH3COOOH and NaCl were the best additives for Hg(0) oxidation. Among the influencing factors, the pH of the LCA and the adding rate of the LCA significantly affected the Hg(0) removal. The coexisting gases, SO2 and NO, were characterized as either increasing or inhibiting in the removal process, depending on their concentrations. Under optimal reaction conditions, the efficiency for the single removal of Hg(0) was 91%. Under identical conditions, the efficiencies of the simultaneous removal of SO2, NO and Hg(0) were 100%, 79.5% and 80.4%, respectively. Finally, the reaction mechanism for the simultaneous removal of SO2, NO and Hg(0) was proposed based on the characteristics of the removal products as determined by X-ray diffraction (XRD), atomic fluorescence spectrometry (AFS), the analysis of the electrode potentials, and through data from related research references.

  4. Systematics and anomalies in rare earth/aluminum bromide vapor complexes: thermodynamic properties of the vapor complexes LnAl3Br12 from Ln = Sc to Ln = Lu.

    PubMed

    Wang, Zhi-Chang; Yu, Jin

    2007-05-14

    Systematics and anomalies in the rare earth/aluminum bromide vapor complexes have been investigated by the phase equilibrium-quenching experiments. The measurements suggest that the LnAl3Br12 complexes are the predominant vapor complexes for the 16 rare earth elements Ln = Sc, Y, La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb, and Lu in the temperature range 601-833 K and pressure range 0.01-0.22 MPa, which is different from the rare earth/aluminum chloride systems, where the predominant vapor complexes are LnAl3Cl12 from Ln = La to Ln = Lu, but LnAl2Cl9 for Ln = Sc and Y are roughly in the same ranges, which indicates the importance of the halogen anion radius on the rare earth vapor complex formation. In the temperature and pressure ranges, gaseous Al2Br6 and AlBr3 are dominant species and the molar fraction of LnAl3Br12 is normally less than 0.01. Thermodynamic functions of the reactions LnBr3(s) + (3/2)Al2Br6(g) = LnAl3Br12(g) were calculated from the measurements for the 16 rare earth elements and then smoothly interpolated for the radioelement Ln = Pm. The standard molar enthalpies and standard molar entropies show significant Gd divergences from LaAl3Br12 to LuAl3Br12 when plotted as functions of the rare earth atomic number. They also suggest nearly linear manner for ScAl3Br12, LuAl3Br12, YAl3Br12, and LaAl3Br12 when plotted as functions of the rare earth ionic radius.

  5. Heat flow in vapor dominated areas of the Yellowstone Plateau Volcanic Field: Implications for the thermal budget of the Yellowstone Caldera

    NASA Astrophysics Data System (ADS)

    Hurwitz, Shaul; Harris, Robert N.; Werner, Cynthia A.; Murphy, Fred

    2012-10-01

    Characterizing the vigor of magmatic activity in Yellowstone requires knowledge of the mechanisms and rates of heat transport between magma and the ground surface. We present results from a heat flow study in two vapor dominated, acid-sulfate thermal areas in the Yellowstone Caldera, the 0.11 km2 Obsidian Pool Thermal Area (OPTA) and the 0.25 km2 Solfatara Plateau Thermal Area (SPTA). Conductive heat flux through a low permeability layer capping large vapor reservoirs is calculated from soil temperature measurements at >600 locations and from laboratory measurements of soil properties. The conductive heat output is 3.6 ± 0.4 MW and 7.5 ± 0.4 MW from the OPTA and the SPTA, respectively. The advective heat output from soils is 1.3 ± 0.3 MW and 1.2 ± 0.3 MW from the OPTA and the SPTA, respectively and the heat output from thermal pools in the OPTA is 6.8 ± 1.4 MW. These estimates result in a total heat output of 11.8 ± 1.4 MW and 8.8 ± 0.4 MW from OPTA and SPTA, respectively. Focused zones of high heat flux in both thermal areas are roughly aligned with regional faults suggesting that faults in both areas serve as conduits for the rising acid vapor. Extrapolation of the average heat flux from the OPTA (103 ± 2 W·m-2) and SPTA (35 ± 3 W·m-2) to the ˜35 km2 of vapor dominated areas in Yellowstone yields 3.6 and 1.2 GW, respectively, which is less than the total heat output transported by steam from the Yellowstone Caldera as estimated by the chloride inventory method (4.0 to 8.0 GW).

  6. Heat flow in vapor dominated areas of the Yellowstone Plateau volcanic field: implications for the thermal budget of the Yellowstone Caldera

    USGS Publications Warehouse

    Hurwitz, Shaul; Harris, Robert; Werner, Cynthia Anne; Murphy, Fred

    2012-01-01

    Characterizing the vigor of magmatic activity in Yellowstone requires knowledge of the mechanisms and rates of heat transport between magma and the ground surface. We present results from a heat flow study in two vapor dominated, acid-sulfate thermal areas in the Yellowstone Caldera, the 0.11 km2 Obsidian Pool Thermal Area (OPTA) and the 0.25 km2 Solfatara Plateau Thermal Area (SPTA). Conductive heat flux through a low permeability layer capping large vapor reservoirs is calculated from soil temperature measurements at >600 locations and from laboratory measurements of soil properties. The conductive heat output is 3.6 ± 0.4 MW and 7.5 ± 0.4 MW from the OPTA and the SPTA, respectively. The advective heat output from soils is 1.3 ± 0.3 MW and 1.2 ± 0.3 MW from the OPTA and the SPTA, respectively and the heat output from thermal pools in the OPTA is 6.8 ± 1.4 MW. These estimates result in a total heat output of 11.8 ± 1.4 MW and 8.8 ± 0.4 MW from OPTA and SPTA, respectively. Focused zones of high heat flux in both thermal areas are roughly aligned with regional faults suggesting that faults in both areas serve as conduits for the rising acid vapor. Extrapolation of the average heat flux from the OPTA (103 ± 2 W·m−2) and SPTA (35 ± 3 W·m−2) to the ~35 km2 of vapor dominated areas in Yellowstone yields 3.6 and 1.2 GW, respectively, which is less than the total heat output transported by steam from the Yellowstone Caldera as estimated by the chloride inventory method (4.0 to 8.0 GW).

  7. Comparison of measured and modeled radiation, heat and water vapor fluxes: FIFE pilot study

    NASA Technical Reports Server (NTRS)

    Blad, Blaine L.; Verma, Shashi B.; Hubbard, Kenneth G.; Starks, Patrick; Hays, Cynthia; Norman, John M.; Waltershea, Elizabeth

    1988-01-01

    The primary objectives of the 1985 study were to test the feasibility of using radio frequency receivers to collect data from automated weather stations and to evaluate the use of the data collected by the automated weather stations for modeling the fluxes of latent heat, sensible heat, and radiation over wheat. The model Cupid was used to calculate these fluxes which were compared with fluxes of these entities measured using micrometeorological techniques. The primary objectives of the 1986 study were to measure and model reflected and emitted radiation streams at a few locations within the First International Satellite Land-Surface Climatology Project Field Experiment (FIFE) site and to compare modeled and measured latent heat and sensible heat fluxes from the prairie vegetation.

  8. Comparison of measured and modeled radiation, heat and water vapor fluxes: FIFE pilot study

    NASA Technical Reports Server (NTRS)

    Blad, Blaine L.; Hubbard, Kenneth G.; Verma, Shashi B.; Starks, Patrick; Norman, John M.; Walter-Shea, Elizabeth

    1987-01-01

    The feasibility of using radio frequency receivers to collect data from automated weather stations to model fluxes of latent heat, sensible heat, and radiation using routine weather data collected by automated weather stations was tested and the estimated fluxes were compared with fluxes measured over wheat. The model Cupid was used to model the fluxes. Two or more automated weather stations, interrogated by radio frequency and other means, were utilized to examine some of the climatic variability of the First ISLSCP (International Satellite Land-Surface Climatology Project) Field Experiment (FIFE) site, to measure and model reflected and emitted radiation streams from various locations at the site and to compare modeled latent and sensible heat fluxes with measured values. Some bidirectional reflected and emitted radiation data were collected from 23 locations throughout the FIFE site. Analysis of these data along with analysis of the measured sensible and latent heat fluxes is just beginning.

  9. Heat capacity contributions to the formation of inclusion complexes.

    PubMed

    Olvera, Angeles; Pérez-Casas, Silvia; Costas, Miguel

    2007-10-04

    An analysis scheme for the formation of the inclusion complexes in water is presented. It is exemplified for the case where the host is alpha-cyclodextrin and the guest is a linear alcohol (1-propanol to 1-octanol) or the isomers of 1-pentanol. Eight transfer isobaric heat capacities, DeltatCp, involving different initial and final states are evaluated at infinite dilution of the guest using both data determined in this work and from the literature. Apart from the usual definition for the inclusion heat capacity change, three inclusion transfers are used. The sign of each DeltatCp indicates if the transfer is an order-formation or an order-destruction process. From the DeltatCp data, the main contributions to the heat capacity of cyclodextrin complexation, namely, those due to dehydration of the hydrophobic section of the guest molecule, H-bond formation, formation of hydrophobic interactions, and release of water molecules from the cyclodextrin cavity, are estimated. The relative weight of each of these contributions to the DeltatCp values is discussed, providing a better characterization of the molecular recognition process involved in the inclusion phenomena.

  10. Water injection into vapor- and liquid-dominated reservoirs: Modeling of heat transfer and mass transport

    SciTech Connect

    Pruess, K.; Oldenburg, C.; Moridis, G.; Finsterle, S.

    1997-12-31

    This paper summarizes recent advances in methods for simulating water and tracer injection, and presents illustrative applications to liquid- and vapor-dominated geothermal reservoirs. High-resolution simulations of water injection into heterogeneous, vertical fractures in superheated vapor zones were performed. Injected water was found to move in dendritic patterns, and to experience stronger lateral flow effects than predicted from homogeneous medium models. Higher-order differencing methods were applied to modeling water and tracer injection into liquid-dominated systems. Conventional upstream weighting techniques were shown to be adequate for predicting the migration of thermal fronts, while higher-order methods give far better accuracy for tracer transport. A new fluid property module for the TOUGH2 simulator is described which allows a more accurate description of geofluids, and includes mineral dissolution and precipitation effects with associated porosity and permeability change. Comparisons between numerical simulation predictions and data for laboratory and field injection experiments are summarized. Enhanced simulation capabilities include a new linear solver package for TOUGH2, and inverse modeling techniques for automatic history matching and optimization.

  11. Vapor Bubbles

    NASA Astrophysics Data System (ADS)

    Prosperetti, Andrea

    2017-01-01

    This article reviews the fundamental physics of vapor bubbles in liquids. Work on bubble growth and condensation for stationary and translating bubbles is summarized and the differences with bubbles containing a permanent gas stressed. In particular, it is shown that the natural frequency of a vapor bubble is proportional not to the inverse radius, as for a gas bubble, but to the inverse radius raised to the power 2/3. Permanent gas dissolved in the liquid diffuses into the bubble with strong effects on its dynamics. The effects of the diffusion of heat and mass on the propagation of pressure waves in a vaporous bubbly liquid are discussed. Other topics briefly touched on include thermocapillary flow, plasmonic nanobubbles, and vapor bubbles in an immiscible liquid.

  12. Re-evaluation of the reported experimental values of the heat of vaporization of N-methylacetamide

    PubMed Central

    MacKerell, Alexander D.; Shim, Ji Hyun; Anisimov, Victor M.

    2010-01-01

    The accuracy of empirical force fields is inherently related to the quality of the target data used for optimization of the model. With the heat of vaporization (ΔHvap) of N-methylacetamide (NMA), a range of values have been reported as target data for optimization of the nonbond parameters associated with the peptide bond in proteins. In the present work, the original experimental data and Antoine constants used for the determination of the ΔHvap of NMA are reanalyzed. Based on this analysis, the wide range of ΔHvap values reported in the literature are shown to be due to incorrect reporting of the temperatures at which the original values were extracted and limitations in the quality of experimental vapor pressure-temperature data over a wide range of temperatures. Taking these problems into account, a consistent ΔHvap value is extracted from three studies for which experimental data are available. This analysis suggests that the most reliable value for ΔHvap is 13.0±0.1 at 410 K for use in force field optimization studies. The present results also indicate that similar analyses, including analysis of Antoine constants alone, may be of utility when reported ΔHvap values are not consistent for a given neat liquid. PMID:20445813

  13. Vapor pressures and calculated heats of vaporization of concentrated nitric acid solutions in the composition range 71 to 89 percent nitrogen dioxide, 1 to 10 percent water, and in the temperature range 10 to 60 degrees C

    NASA Technical Reports Server (NTRS)

    Mckeown, A B; Belles, Frank E

    1954-01-01

    Total vapor pressures were measured for 16 acid mixtures of the ternary system nitric acid, nitrogen dioxide, and water within the temperature range 10 degrees to 60 degrees Celsius, and with the composition range 71 to 89 weight percent nitric acid, 7 to 20 weight percent nitrogen dioxide, and 1 to 10 weight percent water. Heats of vaporization were calculated from the vapor pressure measurements for each sample for the temperatures 25, 40, and 60 degrees Celsius. The ullage of the apparatus used for the measurements was 0.46. Ternary diagrams showing isobars as a function of composition of the system were constructed from experimental and interpolated data for the temperatures 25, 40, 45, and 60 degrees C and are presented herein.

  14. Relationship between 578-nm (copper vapor) laser beam geometry and heat distribution within biological tissues

    NASA Astrophysics Data System (ADS)

    Ilyasov, Ildar K.; Prikhodko, Constantin V.; Nevorotin, Alexey J.

    1995-01-01

    Monte Carlo (MC) simulation model and the thermoindicative tissue phantom were applied for evaluation of a depth of tissue necrosis (DTN) as a result of quasi-cw copper vapor laser (578 nm) irradiation. It has been shown that incident light focusing angle is essential for DTN. In particular, there was a significant rise in DTN parallel to elevation of this angle up to +20 degree(s)C and +5 degree(s)C for both the MC simulation and tissue phantom models, respectively, with no further increase in the necrosis depth above these angles. It is to be noted that the relationship between focusing angles and DTN values was apparently stronger for the real target compared to the MC-derived hypothetical one. To what extent these date are applicable for medical practice can be evaluated in animal models which would simulate laser-assisted therapy for PWS or related dermatologic lesions with converged 578 nm laser beams.

  15. Performance Analysis of Stirling Engine-Driven Vapor Compression Heat Pump System

    NASA Astrophysics Data System (ADS)

    Kagawa, Noboru

    Stirling engine-driven vapor compression systems have many unique advantages including higher thermal efficiencies, preferable exhaust gas characteristics, multi-fuel usage, and low noise and vibration which can play an important role in alleviating environmental and energy problems. This paper introduces a design method for the systems based on reliable mathematical methods for Stirling and Rankin cycles using reliable thermophysical information for refrigerants. The model deals with a combination of a kinematic Stirling engine and a scroll compressor. Some experimental coefficients are used to formulate the model. The obtained results show the performance behavior in detail. The measured performance of the actual system coincides with the calculated results. Furthermore, the calculated results clarify the performance using alternative refrigerants for R-22.

  16. Water, heat, and vapor flow in a deep vadose zone under arid and hyper-arid conditions: a numerical study.

    NASA Astrophysics Data System (ADS)

    Madi, Raneem; de Rooij, Gerrit H.

    2017-04-01

    Groundwater recharge in arid regions is notoriously difficult to quantify. One reason is data scarcity: reliable weather records (rainfall, potential evapotranspiration rate, temperature) are typically lacking, the soil properties over the entire extent of the often very deep vadose zone are usually unknown, and the effect of sparse vegetation, wadis, (biological) soil crusts, and hard pans on infiltration and evaporation is difficult to quantify. Another reason is the difficulty of modeling the intricately coupled relevant processes over extended periods of time: coupled flow of liquid water, water vapor, and heat in a very deep soil in view of considerable uncertainty at the soil surface as indicated above, and over large spatial extents. In view of this myriad of problems, we limited ourselves to the simulation of 1-dimensional coupled flow of water, heat, and vapor in an unvegetated deep vadose zone. The conventional parameterizations of the soil hydraulic properties perform poorly under very dry conditions. We therefore selected an alternative that was developed specifically for dry circumstances and modified another to eliminate the physically implausible residual water content that rendered it of limited use for desert environments. The issue of data scarcity was resolved by using numerically generated rainfall records combined with a simple model for annual and daily temperature fluctuations. The soil was uniform, and the groundwater depth was constant at 100 m depth, which provided the lower boundary condition. The geothermal gradient determined the temperature at the groundwater level. We generated two scenarios with 120 years of weather in an arid and a hyper-arid climate. The initial condition was established by first starting with a somewhat arbitrary unit gradient initial condition corresponding to a small fraction of the annual average rainfall and let the model run through the 120-year atmospheric forcing. The resulting profile of matric potential

  17. Calibrated vapor generator source

    DOEpatents

    Davies, J.P.; Larson, R.A.; Goodrich, L.D.; Hall, H.J.; Stoddard, B.D.; Davis, S.G.; Kaser, T.G.; Conrad, F.J.

    1995-09-26

    A portable vapor generator is disclosed that can provide a controlled source of chemical vapors, such as, narcotic or explosive vapors. This source can be used to test and calibrate various types of vapor detection systems by providing a known amount of vapors to the system. The vapor generator is calibrated using a reference ion mobility spectrometer. A method of providing this vapor is described, as follows: explosive or narcotic is deposited on quartz wool, placed in a chamber that can be heated or cooled (depending on the vapor pressure of the material) to control the concentration of vapors in the reservoir. A controlled flow of air is pulsed over the quartz wool releasing a preset quantity of vapors at the outlet. 10 figs.

  18. Calibrated vapor generator source

    DOEpatents

    Davies, John P.; Larson, Ronald A.; Goodrich, Lorenzo D.; Hall, Harold J.; Stoddard, Billy D.; Davis, Sean G.; Kaser, Timothy G.; Conrad, Frank J.

    1995-01-01

    A portable vapor generator is disclosed that can provide a controlled source of chemical vapors, such as, narcotic or explosive vapors. This source can be used to test and calibrate various types of vapor detection systems by providing a known amount of vapors to the system. The vapor generator is calibrated using a reference ion mobility spectrometer. A method of providing this vapor is described, as follows: explosive or narcotic is deposited on quartz wool, placed in a chamber that can be heated or cooled (depending on the vapor pressure of the material) to control the concentration of vapors in the reservoir. A controlled flow of air is pulsed over the quartz wool releasing a preset quantity of vapors at the outlet.

  19. Open-cycle vapor-compression heat pump. Annual report, April 1983-April 1984

    SciTech Connect

    Becker, F.E.; Ruggles, A.E.

    1984-05-01

    Large quantities of low-grade energy in the form of low-pressure steam and low-temperature heat are wasted by industry. The practical and economical recovery of energy from these sources is often limited by the number of applications for the use of low-temperature heat. Thermo Electron has developed an open-cycle steam-heat-pump system capable of the direct recovery and upgrading of low-grade waste steam. The system compresses low-pressure waste steam (or steam made from sources of low-temperature waste heat) to produce high-pressure steam suitable for use in industrial processes. A prototype system has been developed that is capable of recovering and recompressing up to 10,000 lb/hr of waste steam, while using only 50 percent of the fuel that would be required to produce comparable steam in a boiler. The prototype steam recompression system, using a 2200-cfm rotary screw compressor driven by a 500-hp natural-gas engine, was tested at Thermo Electron and then installed at the Monsanto Company in western Massachusetts for a yearlong field test.

  20. Open-cycle vapor compression heat pump. Final report, January 1979-January 1985

    SciTech Connect

    Becker, F.E.; Ruggles, A.E.

    1985-03-01

    Large quantities of low-grade energy in the form of low-pressure steam and low-temperature heat are often discharged to the environment by industry. The practical and economical recovery of energy from these sources is often limited by the number of applications that can directly use low-temperature heat. Thermo Electron has developed an open-cycle steam heat-pump system capable of the direct recovery and upgrading of low-grade waste energy. The system compresses low-pressure waste steam (or steam made from sources of low-temperature waste heat) to produce high-pressure steam suitable for use in industrial processes. A prototype system has been developed that is capable of recovering and recompressing up to 10,000 lb/hr of waste steam, while using only 50% of the fuel that would be required to produce comparable steam in a boiler. The prototype steam-recompression system, using a 2200-cfm rotary-screw compressor, driven by a 500-hp natural-gas engine, was tested at Thermo Electron and then installed at the Monsanto Company in western Massachusetts for a year-long field test.

  1. Protection against cold in prehospital care: evaporative heat loss reduction by wet clothing removal or the addition of a vapor barrier--a thermal manikin study.

    PubMed

    Henriksson, Otto; Lundgren, Peter; Kuklane, Kalev; Holmér, Ingvar; Naredi, Peter; Bjornstig, Ulf

    2012-02-01

    In the prehospital care of a cold and wet person, early application of adequate insulation is of utmost importance to reduce cold stress, limit body core cooling, and prevent deterioration of the patient's condition. Most prehospital guidelines on protection against cold recommend the removal of wet clothing prior to insulation, and some also recommend the use of a waterproof vapor barrier to reduce evaporative heat loss. However, there is little scientific evidence of the effectiveness of these measures. Using a thermal manikin with wet clothing, this study was conducted to determine the effect of wet clothing removal or the addition of a vapor barrier on thermal insulation and evaporative heat loss using different amounts of insulation in both warm and cold ambient conditions. A thermal manikin dressed in wet clothing was set up in accordance with the European Standard for assessing requirements of sleeping bags, modified for wet heat loss determination, and the climatic chamber was set to -15 degrees Celsius (°C) for cold conditions and +10°C for warm conditions. Three different insulation ensembles, one, two or seven woollen blankets, were chosen to provide different levels of insulation. Five different test conditions were evaluated for all three levels of insulation ensembles: (1) dry underwear; (2) dry underwear with a vapor barrier; (3) wet underwear; (4) wet underwear with a vapor barrier; and (5) no underwear. Dry and wet heat loss and thermal resistance were determined from continuous monitoring of ambient air temperature, manikin surface temperature, heat flux and evaporative mass loss rate. Independent of insulation thickness or ambient temperature, the removal of wet clothing or the addition of a vapor barrier resulted in a reduction in total heat loss of 19-42%. The absolute heat loss reduction was greater, however, and thus clinically more important in cold environments when little insulation is available. A similar reduction in total heat loss

  2. Heat strain reduction by ice-based and vapor compression liquid cooling systems with a toxic agent protective uniform.

    PubMed

    Cadarette, Bruce S; Levine, Leslie; Kolka, Margaret A; Proulx, Gary N; Correa, Mathew M; Sawka, Michael N

    2002-07-01

    The purpose of this study was to compare a vapor compression microclimate cooling system (MCC) and a personal ice cooling system (PIC) for their effectiveness in reducing physiological strain when used with cooling garments worn under the impermeable self-contained toxic environment protective outfit (STEPO). A second comparison was done between the use of total body (TOTAL) and hooded shirt-only (SHIRT) cooling garments with both the MCC and PIC systems. It was hypothesized that the cooling systems would be equally effective, and total body cooling would allow 4 h of physical work in the heat while wearing STEPO. Eight subjects (six men, two women) attempted four experiments at 38 degrees C (100 degrees F), 30% rh, 0.9 m x sec(-1) wind, while wearing the STEPO. Subjects attempted 4 h of treadmill walking (rest/exercise cycles of 10/20 min) at a time-weighted metabolic rate of 303 +/- 50 W. Exposure time was not different between MCC and PIC, but exposure time was greater with TOTAL (131 +/- 66 min) than with SHIRT (83 +/- 27 min) for both cooling systems (p < 0.05). Cooling rate was not different between MCC and PIC, but cooling rate while wearing TOTAL (362 +/- 52 W) was greater than with SHIRT (281 +/- 48 W) (p < 0.05). Average heat storage was lower with MCC (39 +/- 20 W x m(-2)) than with PIC (50 +/- 17 W x m(-2)) in both TOTAL and SHIRT (p < 0.05). Also, average heat storage while wearing TOTAL (34 +/- 19 W x m(-2)) was less than with SHIRT (55 +/- 13 W x m(-2)) for both cooling systems (p < 0.05). The Physiological Strain Index (PSI) was lower in MCC-TOTAL (2.4) than MCC-SHIRT (3.7), PIC-SHIRT (3.8), and PIC-TOTAL (3.3) after 45 min of heat exposure (p < 0.05). Total body circulating liquid cooling was more effective than shirt-only cooling under the impermeable STEPO uniform, providing a greater cooling rate, allowing longer exposure time, and reducing the rate of heat storage. The MCC and PIC systems were equally effective during heat exposure, but neither

  3. The role of water vapor and its associated latent heating in extreme Beaufort coastal storm surge events

    NASA Astrophysics Data System (ADS)

    Gyakum, J. R.; Small, D. L.; Atallah, E.; Liu, N.; Kuo, Y.

    2009-12-01

    During the rather limited ice-free season that typically may occur from late July through early October, the Beaufort Sea region is susceptible to extreme windstorms, many of which produce damaging storm surges to low-lying coastal communities. During the most recent years, the ice-free season has lengthened, suggesting an increased vulnerability of coastal communities to cyclogenesis-related windstorms. Therefore, our research focuses on the dynamic and thermodynamic mechanisms responsible for significant surface wind events during the ice-free season in this region. We demonstrate that these storm surge events are often associated with the generation of large-scale atmospheric circulation regomes conducive to North American droughts. Our analysis methodology includes the detailed synoptic-dynamic analysis, including numerical experiments, on a case of an especially long-lived extreme storm surge that occurred in September 1999. We utilize conventional surface and upper-air station data, along with satellite and ground-based water vapor data. We also utilize global and regional reanalysis data to document the synoptic-scale and mesoscale environments associated with the cyclogenesis events. Our numerical experiments with the Weather Research and Forecasting (WRF) model include sensitivity testing with COSMIC-derived water vapor data, and sensitivity tests to illustrate the relative roles that latent heating plays in the storm surge event, at various stages in its lifecycle. A particularly important finding of our research on the devastating September 1999 storm surge event is that a relatively rare case of explosive cyclogenesis in the Gulf of Alaska is a key player in this Beaufort storm surge. The deep-tropospheric latent heating during the explosive cyclogenesis generates a dynamic tropopause ridge. This ridge in turn induces surface ridging that contributes to the strong west-northwesterlies associated with the storm surge. This generation of the dynamic

  4. An experimental study of the stability of copper chloride complexes in water vapor at elevated temperatures and pressures

    NASA Astrophysics Data System (ADS)

    Archibald, S. M.; Migdisov, A. A.; Williams-Jones, A. E.

    2002-05-01

    The solubility of copper chloride in liquid-undersaturated HCl-bearing water vapor was investigated experimentally at temperatures of 280 to 320°C and pressures up to 103 bars. Results of these experiments show that the solubility of copper in the vapor phase is significant and increases with increasing fH 2O , but is retrograde with respect to temperature. This solubility is attributed to the formation of hydrated copper-chloride gas species, interpreted to have a copper-chlorine ratio of 1:1 (e.g., CuCl, Cu 3Cl 3, etc.) and a hydration number varying from 7.6 at 320°C, to 6.0 at 300°C, and 6.1 at 280°C. Complex formation is proposed to have occurred through the reaction: 3 CuCl solid+nH 2O gas⇋ Cu 3Cl 3·(H 2O) ngas Log K values determined for this reaction are -21.46 ± 0.05 at 280°C (n = 7.6), -19.03 ± 0.10 at 300°C (n = 6.0), and -19.45 ± 0.12 at 320°C (n = 6.1), if it is assumed that the vapor species is the trimer, Cu 3Cl 3(H 2O) 6-8. Calculations based on the above data indicate that at 300°C and HCl fluxes encountered in passively degassing volcanic systems, the vapor phase could transport copper in concentrations as high as 280 ppm. Theoretically, this vapor could form an economic copper deposit (e.g., 50 million tonnes of 0.5% Cu) in as little as ˜20,500 yr.

  5. A season of heat, water vapor, total hydrocarbon, and ozone fluxes at a subarctic fen

    NASA Technical Reports Server (NTRS)

    Moore, Kathleen E.; Fitzjarrald, David R.; Wofsy, Steven C.; Daube, Bruce C.; Munger, J. William; Bakwin, Peter S.; Crill, Patrick

    1994-01-01

    High-latitude environments are thought to play several critical roles in the global balance of radiatively active trace gases. Adequate documentation of the source and sink strengths for trace gases requires long time series of detailed measurements, including heat and moisture budgets. A fen near Schefferville, Quebec, was instrumented during the summer of 1990 for the measurement of the surface energy, radiation, and moisture balances as well as for eddy correlation estimates of ozone and methane flux. Despite the limited fetch at this site, analysis of the tower flux 'footprint' indicates that at least 80% of the flux observed originates from sources within the fen. Sensible heat fluxes averaged 25% of the daytime net radiation at the site, while the latent heat flux, determined from the energy balance, was 63%; the Bowen ratio varied from 0.2 to 0.8 from day to day, without a seasonal trend to the variation. The competing effects of rooted macrophyte development (with concomitant effects on roughness and transpiration) and the normal shift in synoptic pattern around day 200 to warm, dry conditions results in a lack of net seasonal effect on the energy partitioning. Over the period from days 170 to 230, the evaporation (167 mm) was double the rainfall, while the decline in water level was 107 mm, leaving a net runoff of 0.44 mm/d. The total hydrocarbon flux was 75-120 mg m(exp -2)/d, following a diurnal pattern similar to heat or moisture flux, while the daytime ozone flux was about -1.11 x 10(exp 11) molecules cm(exp -2)/s. A period near the end of the experiment, during week 30, produced the strongest total hydrocarbon flux, associated with warmer deep (1 m) soil temperatures, lower fen water levels, and the late summer shift in wind direction at that time. An early summer 'flush' of total hydrocarbon was not observed.

  6. A season of heat, water vapor, total hydrocarbon, and ozone fluxes at a subarctic fen

    NASA Technical Reports Server (NTRS)

    Moore, Kathleen E.; Fitzjarrald, David R.; Wofsy, Steven C.; Daube, Bruce C.; Munger, J. William; Bakwin, Peter S.; Crill, Patrick

    1994-01-01

    High-latitude environments are thought to play several critical roles in the global balance of radiatively active trace gases. Adequate documentation of the source and sink strengths for trace gases requires long time series of detailed measurements, including heat and moisture budgets. A fen near Schefferville, Quebec, was instrumented during the summer of 1990 for the measurement of the surface energy, radiation, and moisture balances as well as for eddy correlation estimates of ozone and methane flux. Despite the limited fetch at this site, analysis of the tower flux 'footprint' indicates that at least 80% of the flux observed originates from sources within the fen. Sensible heat fluxes averaged 25% of the daytime net radiation at the site, while the latent heat flux, determined from the energy balance, was 63%; the Bowen ratio varied from 0.2 to 0.8 from day to day, without a seasonal trend to the variation. The competing effects of rooted macrophyte development (with concomitant effects on roughness and transpiration) and the normal shift in synoptic pattern around day 200 to warm, dry conditions results in a lack of net seasonal effect on the energy partitioning. Over the period from days 170 to 230, the evaporation (167 mm) was double the rainfall, while the decline in water level was 107 mm, leaving a net runoff of 0.44 mm/d. The total hydrocarbon flux was 75-120 mg m(exp -2)/d, following a diurnal pattern similar to heat or moisture flux, while the daytime ozone flux was about -1.11 x 10(exp 11) molecules cm(exp -2)/s. A period near the end of the experiment, during week 30, produced the strongest total hydrocarbon flux, associated with warmer deep (1 m) soil temperatures, lower fen water levels, and the late summer shift in wind direction at that time. An early summer 'flush' of total hydrocarbon was not observed.

  7. Report: Vapor Intrusion Health Risks at Bannister Federal Complex Not a Concern for Buildings 50 and 52, Unknown for Other Buildings

    EPA Pesticide Factsheets

    Report #11-P-0048, January 5, 2011. Testing at Bannister Federal Complex in February 2010 revealed elevated levels of volatile organic compounds (VOCs) in the soil vapor beneath the foundations of buildings 50 and 52.

  8. Experimental study of a constrained vapor bubble fin heat exchanger in the absence of external natural convection.

    PubMed

    Basu, Sumita; Plawsky, Joel L; Wayner, Peter C

    2004-11-01

    In preparation for a microgravity flight experiment on the International Space Station, a constrained vapor bubble fin heat exchanger (CVB) was operated both in a vacuum chamber and in air on Earth to evaluate the effect of the absence of external natural convection. The long-term objective is a general study of a high heat flux, low capillary pressure system with small viscous effects due to the relatively large 3 x 3 x 40 mm dimensions. The current CVB can be viewed as a large-scale version of a micro heat pipe with a large Bond number in the Earth environment but a small Bond number in microgravity. The walls of the CVB are quartz, to allow for image analysis of naturally occurring interference fringes that give the pressure field for liquid flow. The research is synergistic in that the study requires a microgravity environment to obtain a low Bond number and the space program needs thermal control systems, like the CVB, with a large characteristic dimension. In the absence of natural convection, operation of the CVB may be dominated by external radiative losses from its quartz surface. Therefore, an understanding of radiation from the quartz cell is required. All radiative exchange with the surroundings occurs from the outer surface of the CVB when the temperature range renders the quartz walls of the CVB optically thick (lambda > 4 microns). However, for electromagnetic radiation where lambda < 2 microns, the walls are transparent. Experimental results obtained for a cell charged with pentane are compared with those obtained for a dry cell. A numerical model was developed that successfully simulated the behavior and performance of the device observed experimentally.

  9. Research and development of CVD (chemical vapor deposition) composite heat exchanger: Phase 1 report for the period August 1984-April 1985: (Final report)

    SciTech Connect

    Cole, W.; Metcalfe, C.; Nathanson, D.; Reagan, P.; Shimko, M.

    1985-05-17

    There is significant potential for energy and cost savings in high-temperature industrial processes by recovering the heat from flue-gas streams and using it to preheat combustion air. Although heat exchangers are available to preheat combustion air when the flue gases are clean, heat exchangers to recover heat from dirty and corrosive flue gas do not exist. Thermo Electron Corporation has developed a novel concept for a composite heat exchanger utilizing a ceramic composite material. This integrated concept relates to the one-piece construction of the heat exchanger panels which contain both headers and flow passages in one integrated panel. The ceramic composite material utilizes a woven ceramic cloth substrate which is first infiltrated and then overcoated with silicon carbide using the chemical vapor deposition (CVD) process. In this report, the accomplishments of the Phase 1 efforts are discussed and a description of the Phase 2 development program is presented.

  10. Analysis of Thermally Denatured Depth in Laser Vaporization for Benign Prostatic Hyperplasia using a Simulation of Light Propagation and Heat Transfer (secondary publication)

    PubMed Central

    Takada, Junya; Honda, Norihiro; Hazama, Hisanao; Ioritani, Naomasa

    2016-01-01

    Background and Aims: Laser vaporization of the prostate is expected as a less invasive treatment for benign prostatic hyperplasia (BPH), via the photothermal effect. In order to develop safer and more effective laser vaporization of the prostate, it is essential to set optimal irradiation parameters based on quantitative evaluation of temperature distribution and thermally denatured depth in prostate tissue. Method: A simulation model was therefore devised with light propagation and heat transfer calculation, and the vaporized and thermally denatured depths were estimated by the simulation model. Results: The results of the simulation were compared with those of an ex vivo experiment and clinical trial. Based on the accumulated data, the vaporized depth strongly depended on the distance between the optical fiber and the prostate tissue, and it was suggested that contact laser irradiation could vaporize the prostate tissue most effectively. Additionally, it was suggested by analyzing thermally denatured depth comprehensively that laser irradiation at the distance of 3 mm between the optical fiber and the prostate tissue was useful for hemostasis. Conclusions: This study enabled quantitative and reproducible analysis of laser vaporization for BPH and will play a role in clarification of the safety and efficacy of this treatment. PMID:28765672

  11. Electrospray droplet exposure to organic vapors: metal ion removal from proteins and protein complexes.

    PubMed

    DeMuth, J Corinne; McLuckey, Scott A

    2015-01-20

    The exposure of aqueous nanoelectrospray droplets to various organic vapors can dramatically reduce sodium adduction on protein ions in positive ion mass spectra. Volatile alcohols, such as methanol, ethanol, and isopropanol lead to a significant reduction in sodium ion adduction but are not as effective as acetonitrile, acetone, and ethyl acetate. Organic vapor exposure in the negative ion mode, on the other hand, has essentially no effect on alkali ion adduction. Evidence is presented to suggest that the mechanism by which organic vapor exposure reduces alkali ion adduction in the positive mode involves the depletion of alkali metal ions via ion evaporation of metal ions solvated with organic molecules. The early generation of metal/organic cluster ions during the droplet desolvation process results in fewer metal ions available to condense on the protein ions formed via the charged residue mechanism. These effects are demonstrated with holomyoglobin ions to illustrate that the metal ion reduction takes place without detectable protein denaturation, which might be revealed by heme loss or an increase in charge state distribution. No evidence is observed for denaturation with exposure to any of the organic vapors evaluated in this work.

  12. Improved efficiency and precise temperature control of low-frequency induction-heating pure iron vapor source on ECR ion source

    NASA Astrophysics Data System (ADS)

    Kato, Y.; Takenaka, T.; Yano, K.; Kiriyama, R.; Kurisu, Y.; Nozaki, D.; Muramatsu, M.; Kitagawa, A.; Uchida, T.; Yoshida, Y.; Sato, F.; Iida, T.

    2012-11-01

    Multiply charged ions to be used prospectively are produced from solid pure material in an electron cyclotron resonance ion source (ECRIS). Recently a pure iron source is also required for the production of caged iron ions in the fullerene in order to control cells in vivo in bio-nano science and technology. We adopt directly heating iron rod by induction heating (IH) because it has non-contact with insulated materials which are impurity gas sources. We choose molybdenum wire for the IH coils because it doesn't need water cooling. To improve power efficiency and temperature control, we propose to the new circuit without previously using the serial and parallel dummy coils (SPD) for matching and safety. We made the circuit consisted of inductively coupled coils which are thin-flat and helix shape, and which insulates the IH power source from the evaporator. This coupling coils circuit, i.e. insulated induction heating coil transformer (IHCT), can be move mechanically. The secondary current can be adjusted precisely and continuously. Heating efficiency by using the IHCT is much higher than those of previous experiments by using the SPD, because leakage flux is decreased and matching is improved simultaneously. We are able to adjust the temperature in heating the vapor source around melting point. And then the vapor pressure can be controlled precisely by using the IHCT. We can control ±10K around 1500°C by this method, and also recognize to controlling iron vapor flux experimentally in the extreme low pressures. Now we come into next stage of developing induction heating vapor source for materials with furthermore high temperature melting points above 2000K with the IHCT, and then apply it in our ECRIS.

  13. Improved efficiency and precise temperature control of low-frequency induction-heating pure iron vapor source on ECR ion source

    SciTech Connect

    Kato, Y.; Takenaka, T.; Yano, K.; Kiriyama, R.; Kurisu, Y.; Nozaki, D.; Muramatsu, M.; Kitagawa, A.; Uchida, T.; Yoshida, Y.; Sato, F.; Iida, T.

    2012-11-06

    Multiply charged ions to be used prospectively are produced from solid pure material in an electron cyclotron resonance ion source (ECRIS). Recently a pure iron source is also required for the production of caged iron ions in the fullerene in order to control cells in vivo in bio-nano science and technology. We adopt directly heating iron rod by induction heating (IH) because it has non-contact with insulated materials which are impurity gas sources. We choose molybdenum wire for the IH coils because it doesn't need water cooling. To improve power efficiency and temperature control, we propose to the new circuit without previously using the serial and parallel dummy coils (SPD) for matching and safety. We made the circuit consisted of inductively coupled coils which are thin-flat and helix shape, and which insulates the IH power source from the evaporator. This coupling coils circuit, i.e. insulated induction heating coil transformer (IHCT), can be move mechanically. The secondary current can be adjusted precisely and continuously. Heating efficiency by using the IHCT is much higher than those of previous experiments by using the SPD, because leakage flux is decreased and matching is improved simultaneously. We are able to adjust the temperature in heating the vapor source around melting point. And then the vapor pressure can be controlled precisely by using the IHCT. We can control {+-}10K around 1500 Degree-Sign C by this method, and also recognize to controlling iron vapor flux experimentally in the extreme low pressures. Now we come into next stage of developing induction heating vapor source for materials with furthermore high temperature melting points above 2000K with the IHCT, and then apply it in our ECRIS.

  14. Variably-saturated flow in large weighing lysimeters under dry conditions: parameter identification and predictive modelling using coupled water, vapor and heat flow theory

    NASA Astrophysics Data System (ADS)

    Iden, Sascha; Reineke, Daniela; Koonce, Jeremy; Berli, Markus; Durner, Wolfgang

    2017-04-01

    The prediction of groundwater recharge in arid and semi-arid regions with simulation models requires an accurate simulation of actual evaporation. Actual evaporation from dry soil cannot be predicted without the consideration of the interplay between liquid, vapor and heat flow. Under dry conditions, soil water content and latent heat fluxes are generally low and temperature gradients close to the surface can become extremely high in bare-soil leading to temperature-induced vapor fluxes. Due to this and because of the temperature-dependence of saturation vapor pressure, the near-surface temperature fluctuations must be correctly modeled to predict actual evaporation. We have analyzed water, vapor and heat fluxes in a large weighing Lysimeter (length 3 m, area 4 m2) in the Mohave desert, Nevada. The Lysimeter contains homogenized and packed desert soil and is instrumented with a total of 152 sensors for the measurement of local water content (TDR), matric potential (HDU) and soil temperature. The time series of the lysimeter mass was first corrected manually and semi-automatically to determine hourly fluxes across the upper boundary. Effective soil hydraulic properties were identified by inverse modeling of the lysimeter data. The soil hydraulic functions had to be parameterized with a flexible model accounting for water flow in completely and incompletely-filled capillaries to match the time series of water potential and local water content. The hydraulic properties were then used in a coupled model of water, vapor and heat flow which was driven by meteorological data and the energy balance of the ground surface. The coupled model provided an excellent prediction of local water contents, soil temperatures at different depths and actual evaporation from the lysimeter in a validation period. The difference between the actual evaporation measured with the lysimeter and the evaporation predicted by the process model was only 5 %.

  15. Macroscopic modeling of heat and water vapor transfer with phase change in dry snow based on an upscaling method: Influence of air convection

    NASA Astrophysics Data System (ADS)

    Calonne, N.; Geindreau, C.; Flin, F.

    2015-12-01

    At the microscopic scale, i.e., pore scale, dry snow metamorphism is mainly driven by the heat and water vapor transfer and the sublimation-deposition process at the ice-air interface. Up to now, the description of these phenomena at the macroscopic scale, i.e., snow layer scale, in the snowpack models has been proposed in a phenomenological way. Here we used an upscaling method, namely, the homogenization of multiple-scale expansions, to derive theoretically the macroscopic equivalent modeling of heat and vapor transfer through a snow layer from the physics at the pore scale. The physical phenomena under consideration are steady state air flow, heat transfer by conduction and convection, water vapor transfer by diffusion and convection, and phase change (sublimation and deposition). We derived three different macroscopic models depending on the intensity of the air flow considered at the pore scale, i.e., on the order of magnitude of the pore Reynolds number and the Péclet numbers: (A) pure diffusion, (B) diffusion and moderate convection (Darcy's law), and (C) strong convection (nonlinear flow). The formulation of the models includes the exact expression of the macroscopic properties (effective thermal conductivity, effective vapor diffusion coefficient, and intrinsic permeability) and of the macroscopic source terms of heat and vapor arising from the phase change at the pore scale. Such definitions can be used to compute macroscopic snow properties from 3-D descriptions of snow microstructures. Finally, we illustrated the precision and the robustness of the proposed macroscopic models through 2-D numerical simulations.

  16. Research Strategy for Modeling the Complexities of Turbine Heat Transfer

    NASA Technical Reports Server (NTRS)

    Simoneau, Robert J.

    1996-01-01

    The subject of this paper is a NASA research program, known as the Coolant Flow Management Program, which focuses on the interaction between the internal coolant channel and the external film cooling of a turbine blade and/or vane in an aircraft gas turbine engine. The turbine gas path is really a very complex flow field. The combination of strong pressure gradients, abrupt geometry changes and intersecting surfaces, viscous forces, rotation, and unsteady blade/vane interactions all combine to offer a formidable challenge. To this, in the high pressure turbine, we add the necessity of film cooling. The ultimate goal of the turbine designer is to maintain or increase the high level of turbine performance and at the same time reduce the amount of coolant flow needed to achieve this end. Simply stated, coolant flow is a penalty on the cycle and reduces engine thermal efficiency. Accordingly, understanding the flow field and heat transfer associated with the coolant flow is a priority goal. It is important to understand both the film cooling and the internal coolant flow, particularly their interaction. Thus, the motivation for the Coolant Flow Management Program. The paper will begin with a brief discussion of the management and research strategy, will then proceed to discuss the current attack from the internal coolant side, and will conclude by looking at the film cooling effort - at all times keeping sight of the primary goal the interaction between the two. One of the themes of this paper is that complex heat transfer problems of this nature cannot be attacked by single researchers or even groups of researchers, each working alone. It truly needs the combined efforts of a well-coordinated team to make an impact. It is important to note that this is a government/industry/university team effort.

  17. Research Strategy for Modeling the Complexities of Turbine Heat Transfer

    SciTech Connect

    Simoneau, R.J.

    1996-03-01

    The subject of this paper is a NASA research program, known as the Coolant Flow Management Program, which focuses on the interaction between the internal coolant channel and the external film cooling of a turbine blade and/or vane in an aircraft gas turbine engine. The turbine gas path is really a very complex flow field. The combination of strong pressure gradients, abrupt geometry changes and intersecting surfaces, viscous forces, rotation, and unsteady blade/vane interactions all combine to offer a formidable challenge. To this, in the high pressure turbine, one adds the necessity of film cooling. The ultimate goal of the turbine designer is to maintain or increase the high level of turbine performance and at the same time reduce the amount of coolant flow needed to achieve this end. Simply stated, coolant flow is a penalty on the cycle and reduces engine thermal efficiency. Accordingly, understanding the flow field and heat transfer associated with the coolant flow is a priority goal. It is important to understand both the film cooling and the internal coolant flow, particularly their interaction. Thus, the motivation for the Coolant Flow Management Program. The paper will begin with a brief discussion of the management and research strategy, will then proceed to discuss the current attack from the internal coolant side, and will conclude by looking at the film cooling effort - at all times keeping sight of the primary goal the interaction between the two. One of the themes of this paper is that complex heat transfer problems of this nature cannot be attacked by single researchers or even groups of researchers, each working alone. It truly needs the combined efforts of a well-coordinated team to make an impact. It is important to note that this is a government/industry/university team effort.

  18. Heat Transfer And Vapor Dynamics Induced By Nanosecond Laser Ablation Of Titanium Target

    SciTech Connect

    Hamadi, F.; Amara, E. H.; Mezaoui, D.

    2008-09-23

    A numerical modelling describing a pulsed nanosecond laser interaction with a titanium target is presented, resulting in the study of the plume expansion in vacuum or in background gas, using the species transport model available in Fluent computational fluid dynamics code. The heat transfers in the solid target and the molten material are modeled using an enthalpy formulation for the solid-liquid phase changing. The effect of laser fluences is investigated, and results are presented as a function of time. Moreover, the plasma or the vapour dynamics is calculated by solving a set of Navier-Stokes equations. The plasma absorption by inverse Bremsstrahlung, the ionization states and the density profiles of the Titanium ions and electrons in the plume are interactively included in the Fluent calculation process by the mean of User Defined Functions (UDFs) used in order to take into account the specificity of our problem. The ionization is computed by solving the Saha-Eggert equation assuming local thermodynamic equilibrium (LTE) conditions.

  19. Comparison of gold nanoparticle mediated photoporation: vapor nanobubbles outperform direct heating for delivering macromolecules in live cells.

    PubMed

    Xiong, Ranhua; Raemdonck, Koen; Peynshaert, Karen; Lentacker, Ine; De Cock, Ine; Demeester, Jo; De Smedt, Stefaan C; Skirtach, Andre G; Braeckmans, Kevin

    2014-06-24

    There is a great interest in delivering macromolecular agents into living cells for therapeutic purposes, such as siRNA for gene silencing. Although substantial effort has gone into designing nonviral nanocarriers for delivering macromolecules into cells, translocation of the therapeutic molecules from the endosomes after endocytosis into the cytoplasm remains a major bottleneck. Laser-induced photoporation, especially in combination with gold nanoparticles, is an alternative physical method that is receiving increasing attention for delivering macromolecules in cells. By allowing gold nanoparticles to bind to the cell membrane, nanosized membrane pores can be created upon pulsed laser illumination. Depending on the laser energy, pores are created through either direct heating of the AuNPs or by vapor nanobubbles (VNBs) that can emerge around the AuNPs. Macromolecules in the surrounding cell medium can then diffuse through the pores directly into the cytoplasm. Here we present a systematic evaluation of both photoporation mechanisms in terms of cytotoxicity, cell loading, and siRNA transfection efficiency. We find that the delivery of macromolecules under conditions of VNBs is much more efficient than direct photothermal disturbance of the plasma membrane without any noticeable cytotoxic effect. Interestingly, by tuning the laser energy, the pore size could be changed, allowing control of the amount and size of molecules that are delivered in the cytoplasm. As only a single nanosecond laser pulse is required, we conclude that VNBs are an interesting photoporation mechanism that may prove very useful for efficient high-throughput macromolecular delivery in live cells.

  20. Vapor resistant arteries

    NASA Technical Reports Server (NTRS)

    Shaubach, Robert M. (Inventor); Dussinger, Peter M. (Inventor); Buchko, Matthew T. (Inventor)

    1989-01-01

    A vapor block resistant liquid artery structure for heat pipes. A solid tube artery with openings is encased in the sintered material of a heat pipe wick. The openings are limited to that side of the artery which is most remote from the heat source. The liquid in the artery can thus exit the artery through the openings and wet the sintered sheath, but vapor generated at the heat source is unlikely to move around the solid wall of the artery and reverse its direction in order to penetrate the artery through the openings. An alternate embodiment uses finer pore size wick material to resist vapor entry.

  1. Evaporation of Droplets in Plasma Spray–Physical Vapor Deposition Based on Energy Compensation Between Self-Cooling and Plasma Heat Transfer

    NASA Astrophysics Data System (ADS)

    Liu, Mei-Jun; Zhang, Meng; Zhang, Qiang; Yang, Guan-Jun; Li, Cheng-Xin; Li, Chang-Jiu

    2017-10-01

    In the plasma spray-physical vapor deposition process (PS-PVD), there is no obvious heating to the feedstock powders due to the free molecular flow condition of the open plasma jet. However, this is in contrast to recent experiments in which the molten droplets are transformed into vapor atoms in the open plasma jet. In this work, to better understand the heating process of feedstock powders in the open plasma jet of PS-PVD, an evaporation model of molten ZrO2 is established by examining the heat and mass transfer process of molten ZrO2. The results reveal that the heat flux in PS-PVD open plasma jet (about 106 W/m2) is smaller than that in the plasma torch nozzle (about 108 W/m2). However, the flying distance of molten ZrO2 in the open plasma jet is much longer than that in the plasma torch nozzle, so the heating in the open plasma jet cannot be ignored. The results of the evaporation model show that the molten ZrO2 can be partly evaporated by self-cooling, whereas the molten ZrO2 with a diameter <0.28 μm and an initial temperature of 3247 K can be completely evaporated within the axial distance of 450 mm by heat transfer.

  2. Evaporation of Droplets in Plasma Spray-Physical Vapor Deposition Based on Energy Compensation Between Self-Cooling and Plasma Heat Transfer

    NASA Astrophysics Data System (ADS)

    Liu, Mei-Jun; Zhang, Meng; Zhang, Qiang; Yang, Guan-Jun; Li, Cheng-Xin; Li, Chang-Jiu

    2017-08-01

    In the plasma spray-physical vapor deposition process (PS-PVD), there is no obvious heating to the feedstock powders due to the free molecular flow condition of the open plasma jet. However, this is in contrast to recent experiments in which the molten droplets are transformed into vapor atoms in the open plasma jet. In this work, to better understand the heating process of feedstock powders in the open plasma jet of PS-PVD, an evaporation model of molten ZrO2 is established by examining the heat and mass transfer process of molten ZrO2. The results reveal that the heat flux in PS-PVD open plasma jet (about 106 W/m2) is smaller than that in the plasma torch nozzle (about 108 W/m2). However, the flying distance of molten ZrO2 in the open plasma jet is much longer than that in the plasma torch nozzle, so the heating in the open plasma jet cannot be ignored. The results of the evaporation model show that the molten ZrO2 can be partly evaporated by self-cooling, whereas the molten ZrO2 with a diameter <0.28 μm and an initial temperature of 3247 K can be completely evaporated within the axial distance of 450 mm by heat transfer.

  3. Changes in bioactive compounds and oxidative enzymes of fresh-cut pomegranate arils during storage as affected by deficit irrigation and postharvest vapor heat treatments.

    PubMed

    Peña-Estévez, María E; Gómez, Perla A; Artés, Francisco; Aguayo, Encarna; Martínez-Hernández, Ginés Benito; Galindo, Alejandro; Torecillas, Arturo; Artés-Hernández, Francisco

    2016-12-01

    The effect of postharvest vapor heat treatments at 95℃ (4, 7, and 10 s) regarding a conventional sanitizing treatment with 100 mg NaClO l(-1) on enzyme activities (phenylalanine ammonia lyase, polyphenol oxidase, and peroxidase), phenolic content, and total antioxidant capacity of fresh-cut pomegranates arils throughout 18 days at 5℃ was studied. Furthermore, the effect of two sustained deficit irrigation (SDI) strategies, compared to a standardly irrigated control (CTRL), was also studied on such quality parameters throughout storage. Arils from CTRL-irrigated fruit registered phenylalanine ammonia lyase, peroxidase, and polyphenol oxidase initial activities of 60.6, 382, and 14.4 U g(-1) fw, respectively. Arils from sustained deficit irrigation fruit registered 46-58% lower phenylalanine ammonia lyase values while polyphenol oxidase and peroxidase activities did not register great variants (<9%) among both sustained deficit irrigation treatments. Postharvest vapor heat treatments enhanced phenylalanine ammonia lyase activity in those samples from sustained deficit irrigation fruit although no great peroxidase and polyphenol oxidase (<2-5%) increases were observed. Arils from SDI1 fruit registered higher phenolic content than those values reported for CTRL samples. However, phenolic compounds decreased during storage, in a greater extent for sustained deficit irrigation samples, although 7 s arils achieved better phenolic compounds retention in sustained deficit irrigation samples. Vapor heat treatments reduced up to twofold the total antioxidant capacity losses observed in samples sanitized by conventional NaOCl treatment during shelf life. Conclusively, postharvest vapor heat treatment for 7 and 10 s used to extend the shelf life of pomegranate arils up to 18 days at 5℃ reduced the losses of health-promoting compounds during storage compared to conventional NaOCl sanitizing treatment.

  4. Volatile organometallic complexes suitable for use in chemical vapor depositions on metal oxide films

    DOEpatents

    Giolando, Dean M.

    2003-09-30

    Novel ligated compounds of tin, titanium, and zinc are useful as metal oxide CVD precursor compounds without the detriments of extreme reactivity yet maintaining the ability to produce high quality metal oxide coating by contact with heated substrates.

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

    PubMed Central

    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. PMID:28184144

  6. Hardware Modifications to the US Army Research Laboratory’s Metalorganic Chemical Vapor Deposition (MOCVD) System for Optimization of Complex Oxide Thin Film Fabrication

    DTIC Science & Technology

    2015-04-01

    Substrate 17 4.2.3 Atomic Force Microscopy (AFM) AFM micrographs for the as- deposited STO thin film after hardware modifications were taken... layer -by- layer MOCVD of complex metal oxides and in situ process monitoring. Chemical Vapor Deposition . 2001;7:7–18. 39. Jones AC. MOCVD of...modeling of pulsed MOCVD with ultrasonic atomization of liquid precursor. Chemical Vapor Deposition . 2001;7:85–90. 51. Xie HY, Versteeg VA, Raj R

  7. Nanoscale control of optical heating in complex plasmonic systems.

    PubMed

    Baffou, Guillaume; Quidant, Romain; García de Abajo, F Javier

    2010-02-23

    We introduce a numerical technique to investigate the temperature distribution in arbitrarily complex plasmonic systems subject to external illumination. We perform both electromagnetic and thermodynamic calculations based upon a time-efficient boundary element method. Two kinds of plasmonic systems are investigated in order to illustrate the potential of such a technique. First, we focus on individual particles with various morphologies. In analogy with electrostatics, we introduce the concept of thermal capacitance. This geometry-dependent quantity allows us to assess the temperature increase inside a plasmonic particle from the sole knowledge of its absorption cross section. We present universal thermal-capacitance curves for ellipsoids, rods, disks, and rings. Additionally, we investigate assemblies of nanoparticles in close proximity and show that, despite its diffusive nature, the temperature distribution can be made highly non-uniform even at the nanoscale using plasmonic systems. A significant degree of nanoscale control over the individual temperatures of neighboring particles is demonstrated, depending on the external light wavelength and direction of incidence. We illustrate this concept with simulations of gold sphere dimers and chains in water. Our work opens new possibilities for selectively controlling processes such as local melting for dynamic patterning of textured materials, chemical and metabolic thermal activation, and heat delivery for producing mechanical motion with spatial precision in the nanoscale.

  8. A Coupled Multiphase Fluid Flow And Heat And Vapor Transport Model For Air-Gap Membrane Distillation

    NASA Astrophysics Data System (ADS)

    Mukhopadhyay, Sumit

    2010-05-01

    Membrane distillation (MD) is emerging as a viable desalination technology because of its low energy requirements that can be provided from low-grade, waste heat and because it causes less fouling. In MD, desalination is accomplished by transporting water vapour through a porous hydrophobic membrane. The vapour transport process is governed by the vapour pressure difference between the two sides of a membrane. A variety of configurations have been tested to impose this vapour pressure gradient, however, the air-gap membrane distillation (AGMD) has been found to be the most efficient. The separation mechanism of AGMD and its overall efficiency is based on vapour-liquid equilibrium (VLE). At present, little knowledge is available about the optimal design of such a transmembrane VLE-based evaporation, and subsequent condensation processes. While design parameters for MD have evolved mostly through experimentations, a comprehensive mathematical model is yet to be developed. This is primarily because the coupling and non-linearity of the equations, the interactions between the flow, heat and mass transport regimes, and the complex geometries involved pose a challenging modelling and simulation problem. Yet a comprehensive mathematical model is needed for systematic evaluation of the processes, design parameterization, and performance prediction. This paper thus presents a coupled fluid flow, heat and mass transfer model to investigate the main processes and parameters affecting the performance of an AGMD.

  9. A Visual Technique for Determining Qualitative Aerodynamic Heating Rates on Complex Configurations

    NASA Technical Reports Server (NTRS)

    Stainback, P. Calvin

    1960-01-01

    An experimental investigation was conducted at a test-section Mach number of 4.95 and a stagnation temperature of 400 F to evaluate a visual technique for obtaining qualitative aerodynamic heat-transfer data on complex configurations.This technique utilized a temperature-sensetive paint indicated that this technique was satisfactory for determining qualitative heat-transfer rates on various bodies, some of which exhibited complex flow patterns. The results obtained have been found useful to guide the instrumentation of quantitative heat-transfer models, to supplement quantitative heat-transfer measurements, and to make preliminary heat-transfer studies for new configurations.

  10. A Visual Technique for Determining Qualitative Aerodynamic Heating Rates on Complex Configurations

    NASA Technical Reports Server (NTRS)

    Stainback, P. Calvin

    1960-01-01

    An experimental investigation was conducted at a test-section Mach number of 4.95 and a stagnation temperature of 400 F to evaluate a visual technique for obtaining qualitative aerodynamic heat-transfer data on complex configurations.This technique utilized a temperature-sensetive paint indicated that this technique was satisfactory for determining qualitative heat-transfer rates on various bodies, some of which exhibited complex flow patterns. The results obtained have been found useful to guide the instrumentation of quantitative heat-transfer models, to supplement quantitative heat-transfer measurements, and to make preliminary heat-transfer studies for new configurations.

  11. Vapor generator wand

    NASA Technical Reports Server (NTRS)

    Robelen, David B. (Inventor)

    1996-01-01

    A device for producing a stream of vapor for wind tunnel airflow visualization is described. An electrically conductive heating tube is used to resistively heat a vapor producing liquid. The heating and delivery systems are integrated to allow the device to present a small cross section to the air flow, thereby reducing disturbances due to the device. The simplicity of the design allows for inexpensive implementation and construction. The design is readily scaled for use in various wind tunnel applications. The device may also find uses in manufacturing, producing a vapor for deposition on a substrate.

  12. Isotherms and Kinetics of Water Vapor Sorption/Desorption for Surface Films of Polyion-Surfactant Ion Complex Salts.

    PubMed

    Gustavsson, Charlotte; Piculell, Lennart

    2016-07-14

    Thin films of "complex salts" (CS = ionic surfactants with polymeric counterions) have recently been shown to respond to humidity changes in ambient air by changing their liquid crystalline structure. We here report isotherms and kinetics of water sorption/desorption for ∼10-100 μm films of alkyltrimethylammonium polyacrylate CS, measured in a dynamic gravimetric vapor sorption instrument over a 0-95% relative humidity (RH) range. The sorption per ion pair was similar to that observed for common ionomers. A kinetic model for the water exchange is presented, assuming that the "external" transport between the vapor reservoir and the film surface is rate-determining. The model predicts that the water content, after a small stepwise change of the reservoir RH, should vary exponentially with time, with a time constant proportional to both the slope of the sorption isotherm and the film thickness. These predictions were confirmed for our films over large RH ranges, and the external mass transfer coefficient in our setup was calculated from the experimental data. Expressions derived for the Biot number (ratio of characteristic times for internal and external water transport) for the considered limiting case strongly indicate that external water transport should quite generally affect, or even dominate, the measured kinetics for similarly thin hydrated films.

  13. Synthesis and characterization of carbon nanofibers by catalytic chemical vapor deposition using non-ferromagnetic metal complexes.

    PubMed

    Su, Chi-Jung; Yuan, Wei-Li; Lai, Tzu-Wei; Lei, Chien-Ming

    2014-06-01

    Carbon nanofibers (CNFs) have wide applications in energy storage devices, electrically conducting composites, selective adsorbents, and catalyst supports. Catalytic chemical vapor deposition was carried out in this work to synthesize CNFs at mild temperatures of 700 and 800 degrees C. Non-ferromagnetic metal complexes of La, Nb, and Ti, spread on porous NaX-type zeolite support, were tested as new catalyst. CNFs ranging from 30 to 200 nm in diameter were obtained. Images of transmission electron microscopy showed encapsulated transition-metal nanoparticles by CNFs. X-ray diffraction patterns revealed the crystalline structures of La (FCC), Nb (BCC), and Ti (HCP) formed over zeolite. Magnetic hysteresis loops showed superconductivity from the CNF-encapsulated Nb at 2 K. Raman spectra showed that all the samples possessed graphitic and amorphous carbon structures. Based on the SEM images and Raman spectra, the three metals all catalyzed the synthesis of CNFs.

  14. The effect of dependence between vapor heat capacity, specific heat of evaporation-condensation of irrigating liquid and temperature on thermodynamic parameters of processes gases

    NASA Astrophysics Data System (ADS)

    Khromova, Helen; Oparina, Irene

    2014-08-01

    The results of parameters calculations of the vapor-gas flow and droplets of irrigating liquid in application to the conditions of flue gas cooling in the reactors of the soda ash workshop at "Azot" limited company, Kemerovo, are compared.

  15. ATF1 modulates the heat shock response by regulating the stress-inducible heat shock factor 1 transcription complex.

    PubMed

    Takii, Ryosuke; Fujimoto, Mitsuaki; Tan, Ke; Takaki, Eiichi; Hayashida, Naoki; Nakato, Ryuichiro; Shirahige, Katsuhiko; Nakai, Akira

    2015-01-01

    The heat shock response is an evolutionally conserved adaptive response to high temperatures that controls proteostasis capacity and is regulated mainly by an ancient heat shock factor (HSF). However, the regulation of target genes by the stress-inducible HSF1 transcription complex has not yet been examined in detail in mammalian cells. In the present study, we demonstrated that HSF1 interacted with members of the ATF1/CREB family involved in metabolic homeostasis and recruited them on the HSP70 promoter in response to heat shock. The HSF1 transcription complex, including the chromatin-remodeling factor BRG1 and lysine acetyltransferases p300 and CREB-binding protein (CBP), was formed in a manner that was dependent on the phosphorylation of ATF1. ATF1-BRG1 promoted the establishment of an active chromatin state and HSP70 expression during heat shock, whereas ATF1-p300/CBP accelerated the shutdown of HSF1 DNA-binding activity during recovery from acute stress, possibly through the acetylation of HSF1. Furthermore, ATF1 markedly affected the resistance to heat shock. These results revealed the unanticipated complexity of the primitive heat shock response mechanism, which is connected to metabolic adaptation. Copyright © 2015, American Society for Microbiology. All Rights Reserved.

  16. ATF1 Modulates the Heat Shock Response by Regulating the Stress-Inducible Heat Shock Factor 1 Transcription Complex

    PubMed Central

    Takii, Ryosuke; Fujimoto, Mitsuaki; Tan, Ke; Takaki, Eiichi; Hayashida, Naoki; Nakato, Ryuichiro; Shirahige, Katsuhiko

    2014-01-01

    The heat shock response is an evolutionally conserved adaptive response to high temperatures that controls proteostasis capacity and is regulated mainly by an ancient heat shock factor (HSF). However, the regulation of target genes by the stress-inducible HSF1 transcription complex has not yet been examined in detail in mammalian cells. In the present study, we demonstrated that HSF1 interacted with members of the ATF1/CREB family involved in metabolic homeostasis and recruited them on the HSP70 promoter in response to heat shock. The HSF1 transcription complex, including the chromatin-remodeling factor BRG1 and lysine acetyltransferases p300 and CREB-binding protein (CBP), was formed in a manner that was dependent on the phosphorylation of ATF1. ATF1-BRG1 promoted the establishment of an active chromatin state and HSP70 expression during heat shock, whereas ATF1-p300/CBP accelerated the shutdown of HSF1 DNA-binding activity during recovery from acute stress, possibly through the acetylation of HSF1. Furthermore, ATF1 markedly affected the resistance to heat shock. These results revealed the unanticipated complexity of the primitive heat shock response mechanism, which is connected to metabolic adaptation. PMID:25312646

  17. Solar heated office complex--Greenwood, South Carolina

    NASA Technical Reports Server (NTRS)

    1981-01-01

    Report contains thorough docuumentation of project meeting 85 percent of building heat requirements. System uses roof mounted recirculating water solar panels and underground hot water energy storage. Aluminum film reflectors increase total solar flux captured by panels.

  18. Means and method for vapor generation

    DOEpatents

    Carlson, L.W.

    A liquid, in heat transfer contact with a surface heated to a temperature well above the vaporization temperature of the liquid, will undergo a multiphase (liquid-vapor) transformation from 0% vapor to 100% vapor. During this transition, the temperature driving force or heat flux and the coefficients of heat transfer across the fluid-solid interface, and the vapor percentage influence the type of heating of the fluid - starting as feedwater heating where no vapors are present, progressing to nucleate heating where vaporization begins and some vapors are present, and concluding with film heating where only vapors are present. Unstable heating between nucleate and film heating can occur, accompanied by possibly large and rapid temperature shifts in the structures. This invention provides for injecting into the region of potential unstable heating and proximate the heated surface superheated vapors in sufficient quantities operable to rapidly increase the vapor percentage of the multiphase mixture by perhaps 10 to 30% and thereby effectively shift the multiphase mixture beyond the unstable heating region and up to the stable film heating region.

  19. Means and method for vapor generation

    DOEpatents

    Carlson, Larry W.

    1984-01-01

    A liquid, in heat transfer contact with a surface heated to a temperature well above the vaporization temperature of the liquid, will undergo a multiphase (liquid-vapor) transformation from 0% vapor to 100% vapor. During this transition, the temperature driving force or heat flux and the coefficients of heat transfer across the fluid-solid interface, and the vapor percentage influence the type of heating of the fluid--starting as "feedwater" heating where no vapors are present, progressing to "nucleate" heating where vaporization begins and some vapors are present, and concluding with "film" heating where only vapors are present. Unstable heating between nucleate and film heating can occur, accompanied by possibly large and rapid temperature shifts in the structures. This invention provides for injecting into the region of potential unstable heating and proximate the heated surface superheated vapors in sufficient quantities operable to rapidly increase the vapor percentage of the multiphase mixture by perhaps 10-30% and thereby effectively shift the multiphase mixture beyond the unstable heating region and up to the stable film heating region.

  20. Large-scale fabrication of linear low density polyethylene/layered double hydroxides composite films with enhanced heat retention, thermal, mechanical, optical and water vapor barrier properties

    NASA Astrophysics Data System (ADS)

    Xie, Jiazhuo; Zhang, Kun; Zhao, Qinghua; Wang, Qingguo; Xu, Jing

    2016-11-01

    Novel LDH intercalated with organic aliphatic long-chain anion was large-scale synthesized innovatively by high-energy ball milling in one pot. The linear low density polyethylene (LLDPE)/layered double hydroxides (LDH) composite films with enhanced heat retention, thermal, mechanical, optical and water vapor barrier properties were fabricated by melt blending and blowing process. FT IR, XRD, SEM results show that LDH particles were dispersed uniformly in the LLDPE composite films. Particularly, LLDPE composite film with 1% LDH exhibited the optimal performance among all the composite films with a 60.36% enhancement in the water vapor barrier property and a 45.73 °C increase in the temperature of maximum mass loss rate compared with pure LLDPE film. Furthermore, the improved infrared absorbance (1180-914 cm-1) of LLDPE/LDH films revealed the significant enhancement of heat retention. Therefore, this study prompts the application of LLDPE/LDH films as agricultural films with superior heat retention.

  1. Injection plume behavior in fractured, vapor-dominated reservoirs

    SciTech Connect

    Pruess, Karsten

    1996-01-24

    We discuss fluid flow and heat transfer processes during water injection into hot, fluid-depleted vapor zones. Numerical simulations of injection plumes in fractures, modeled as two-dimensional heterogeneous porous media, indicate complex behavior. Under certain conditions it is possible to make detailed quantitative predictions of vaporization behavior. However, when effects of reservoir heterogeneity are dominant it will only be possible to predict the behavior of injection plumes in general terms.

  2. Numerical modeling of conjugate heat transfer on complex geometries with diagonal Cartesian method. Part 2: Applications

    SciTech Connect

    Carlson, K.D.; Lin, W.L.; Chen, C.J. |

    1999-05-01

    Part 1 of this study discusses the diagonal Cartesian method for temperature analysis. The application of this method to the analysis of flow and conjugate heat transfer in a compact heat exchanger is given in Part 2. In addition to a regular (i.e., Cartesian-oriented) fin arrangement, two complex fin arrangements are modeled using the diagonal Cartesian method. The pressure drop and heat transfer characteristics of the different configurations are compared. It is found that enhanced heat transfer and reduced pressure drop can be obtained with the modified fin arrangements for this compact heat exchanger.

  3. Estimation of spatially distributed latent energy flux over complex terrain using a scanning water-vapor Raman lidar

    SciTech Connect

    Cooper, D.I.; Eichinger, W.; Archuleta, J.; Cottingame, W.; Osborne, M.; Tellier, L.

    1995-09-01

    Evapotranspiration is one of the critical variables in both water and energy balance models of the hydrological system. The hydrologic system is driven by the soil-plant-atmosphere continuum, and as such is a spatially distributed process. Traditional techniques rely on point sensors to collect information that is then averaged over a region. The assumptions involved in spatially average point data is of limited value (1) because of limited sensors in the arrays, (2) the inability to extend and interpret the Measured scalars and estimated fluxes at a point over large areas in complex terrain, and (3) the limited understanding of the relationship between point measurements of spatial processes. Remote sensing technology offers the ability to collect detailed spatially distributed data. However, the Los Alamos National Laboratory`s volume-imaging, scanning water-vapor Raman lidar has been shown to be able to estimate the latent energy flux at a point. The extension of this capability to larger scales over complex terrain represents a step forward. This abstract Outlines the techniques used to estimate the spatially resolved latent energy flux. The following sections describe the site, model, data acquired, and lidar estimated latent energy ``map``.

  4. Surface-driven, one-step chemical vapor deposition of γ-Al4Cu9 complex metallic alloy film

    NASA Astrophysics Data System (ADS)

    Prud'homme, Nathalie; Duguet, Thomas; Samélor, Diane; Senocq, François; Vahlas, Constantin

    2013-10-01

    The present paper is a paradigm for the one-step formation of complex intermetallic coatings by chemical vapor deposition. It genuinely addresses the challenge of depositing an intermetallic coating with comparable contents of Cu and Al. Depending on processing conditions, a pure γ-Al4Cu9 and multi-phase Al-Cu films are grown with wetting properties of the former being similar to its bulk counterpart. The deposition process and its parametric investigation are detailed. Two metalorganic precursors are used taking into account their transport and chemical properties, and deposition temperature ranges. On line and ex situ characterizations enlighten the competition which occurs at the growing surface between molecular fragments, and which limits growth rates. Notably, introducing a partial pressure of hydrogen gas during deposition reduces Al growth rate from dimethylethylamine alane (DMEAA), by displacing the hydrogen desorption equilibrium. This Al partial growth rate decrease is not sufficient to achieve a Cu/Al atomic ratio that is high enough for the formation of intermetallics with close Al and Cu compositions. A fivefold increase of the flux of the gaseous copper(I) cyclopentadienyl triethylphosphine CpCuPEt3, whereas the DMEAA flux remains constant, results in the targeted Al/Cu atomic ratio equal to 44/56. Nevertheless, the global growth rate is rendered extremely low by the deposition inhibition caused by a massive phosphine adsorption (-PEt3). Despite these limitations, the results pave the way towards the conformal coating of complex surface geometries by such intermetallic compounds.

  5. I. Synthesis of group 13 fluoroalkoxide complexes and the chemical vapor deposition of indium oxide films. II. Synthesis of gallium hydrido-thiolate complexes

    NASA Astrophysics Data System (ADS)

    Miinea, Liliana Angela

    A synthetic route to indium fluoroalkoxide complexes was developed and fluorine-doped indium oxide films were prepared from one of the new complexes by chemical vapor deposition. The reaction of indium amide complexes with fluorinated alcohols was found to be a convenient synthetic route to indium fluoroalkoxide complexes. In[N-t-Bu(SiMe3)]3 reacted with (CF3)Me2COH to give the dimer [In{mu-OCMe 2(CF3)}{OCMe2(CF3)}2] 2. In contrast, reactions involving the more acidic alcohols (CF 3)2MeCOH and (CF3)2CHOH yielded products containing t-BuNH2, which was derived from the amide ligands of the starting material. Reactions of (CF3) 2MeCOH and (CF3)2CHOH with In(tmp)3 (tmp = the anion derived from 2,2,6,6-tetramethylpiperidine) and In(NEt 2)3 gave In[OCH(CF3)2]3(Htmp), [H2tmp][In{OCR(CF3)2}4] (R = H or Me), and mer-In[OCMe(CF3)2]3(py) 3. Polycrystalline indium oxide films were deposited at 400-550°C in a low-pressure chemical vapor deposition process from In[OCMe(CF3 )2]3(H2N-t-Bu) and O2 precursors. The films deposited at ≤500°C contained 2-3 atom % fluorine while the film deposited at 550°C had no detectable fluorine incorporation. Films deposited on quartz (˜3600-A thickness) showed >85% transmittance in the 400-800 nm region, and resistivities of 2.56 x 10 -1-2.02 x 10-2 O cm were measured for the as-deposited films. The observed transmittance is in the range reported previously for doped and undoped In2O3, while the resistivity values are higher than those reported for tin, fluorine or sulfur-doped indium oxide. The work on the synthesis of indium fluoroalkoxide complexes prompted an examination of the synthesis of related aluminum and gallium fluoroalkoxide complexes. Aluminum and gallium fluoroalkoxide complexes of formula M(ORf) 3(HNMe2) [M = Al, Rf = CH(CF3)2, CMe 2(CF3) or CMe(CF3)2; M = Ga, Rf = CMe 2(CF3) or CMe(CF3)2] were prepared by reacting the corresponding metal dimethylamide complexes with fluorinated alcohols. An attempt was made to prepare

  6. The influence of radiative heat exchange on the character of gasdynamic flows under conditions of pulsed discharge in high-pressure cesium vapor

    NASA Astrophysics Data System (ADS)

    Baksht, F. G.; Lapshin, V. F.

    2015-01-01

    The gasdynamics of pulse-periodic radiative discharge in high-pressure cesium vapor has been studied in the framework of a two-temperature multifluid model. It is established that, at a limited volume of the gas-discharge tube, the character of gasdynamic flows depends on the conditions of radiative heat exchange in discharge plasma. In cases in which the main contribution to radiative energy losses is related to a spectral region with optical thickness τ R (λ) ˜ 1, there is nonlocal radiative heat exchange in discharge plasma, which is uniformly heated over the entire tube volume and moves from the discharge axis to tube walls during the entire pulse of discharge current. Under the conditions of radiative losses determined by the spectral region where τ R (λ) ≪ 1, the reabsorption of radiation is absent and discharge plasma is nonuniformly heated by the current pulse. This leads to the appearance of reverse motions, so that the heated plasma is partly pushed toward the tube walls and partly returned to the discharge axis.

  7. Metal organic chemical vapor deposition of environmental barrier coatings for the inhibition of solid deposit formation from heated jet fuel

    NASA Astrophysics Data System (ADS)

    Mohan, Arun Ram

    Solid deposit formation from jet fuel compromises the fuel handling system of an aviation turbine engine and increases the maintenance downtime of an aircraft. The deposit formation process depends upon the composition of the fuel, the nature of metal surfaces that come in contact with the heated fuel and the operating conditions of the engine. The objective of the study is to investigate the effect of substrate surfaces on the amount and nature of solid deposits in the intermediate regime where both autoxidation and pyrolysis play an important role in deposit formation. A particular focus has been directed to examining the effectiveness of barrier coatings produced by metal organic chemical vapor deposition (MOCVD) on metal surfaces for inhibiting the solid deposit formation from jet fuel degradation. In the first part of the experimental study, a commercial Jet-A sample was stressed in a flow reactor on seven different metal surfaces: AISI316, AISI 321, AISI 304, AISI 347, Inconel 600, Inconel 718, Inconel 750X and FecrAlloy. Examination of deposits by thermal and microscopic analysis shows that the solid deposit formation is influenced by the interaction of organosulfur compounds and autoxidation products with the metal surfaces. The nature of metal sulfides was predicted by Fe-Ni-S ternary phase diagram. Thermal stressing on uncoated surfaces produced coke deposits with varying degree of structural order. They are hydrogen-rich and structurally disordered deposits, spherulitic deposits, small carbon particles with relatively ordered structures and large platelets of ordered carbon structures formed by metal catalysis. In the second part of the study, environmental barrier coatings were deposited on tube surfaces to inhibit solid deposit formation from the heated fuel. A new CVD system was configured by the proper choice of components for mass flow, pressure and temperature control in the reactor. A bubbler was designed to deliver the precursor into the reactor

  8. The effect of heated vapor-phase acidification on organic carbon concentrations and isotopic values in geologic rock samples

    NASA Astrophysics Data System (ADS)

    Wang, R. Z.; West, A. J.; Yager, J. A.; Rollins, N.; Li, G.; Berelson, W.

    2016-12-01

    Carbon signatures recorded in the modern and geologic rock record can give insight on the Earth's carbon cycle through time. This is especially true for organic carbon (OC), which can help us understand how the biosphere has evolved over Earth's history. However, carbon recorded in rocks is a combination of OC and inorganic carbon (IC) mostly in the form of carbonate minerals. To measure OC, IC must therefore first be removed through a process called "decarbonation." This is often done through a leaching process with hydrochloric acid (HCl). However, three well known problems exist for the decarbonation process: 1) Incomplete removal of IC, 2) Unintentional removal of OC, and 3) Addition of false carbon blank. Currently, vapor (gas) phase removal of OC is preferred to liquid phase treatment because it has been shown that OC is lost to solubilization during liquid phase acidification. Vapor phase treatment is largely thought to avoid the problem of OC loss, but this has not yet been rigorously investigated. This study investigates that assumption and shows that vapor phase treatment can cause unintentional OC loss. We show that vapor phase treatment must be sensitive to rock type and treatment length to produce robust OC isotopic measurements and concentrations.

  9. Vapor pressure and evaporation rate of certain heat-resistant compounds in a vacuum at high temperatures

    SciTech Connect

    Bolgar, A.S.; Verkhoglyadova, T.S.; Samsonov, G.V.

    1985-02-01

    The vapor pressure and evaporation rate of borides of titanium, zirconium, and chrome and of strontium and carbides of titanium, zirconium, and chrome, molybdenum silicide and nitrides of titanium, niobium, and tantalum in a vacuum were studied. It is concluded that all subject compounds evaporate by molecular structures except AlB sub 12' which dissociates, losing the aluminum.

  10. Vapor pressure and evaporation rate of certain heat-resistant compounds in a vacuum at high temperatures

    NASA Technical Reports Server (NTRS)

    Bolgar, A. S.; Verkhoglyadova, T. S.; Samsonov, G. V.

    1985-01-01

    The vapor pressure and evaporation rate of borides of titanium, zirconium, and chrome; and of strontium and carbides of titanium, zirconium, and chrome, molybdenum silicide; and nitrides of titanium, niobium, and tantalum in a vacuum were studied. It is concluded that all subject compounds evaporate by molecular structures except AlB sub 12' which dissociates, losing the aluminum.

  11. Interpretation of MSL REMS data using 1D coupled heat and water vapor transport model of Mars subsurface

    NASA Astrophysics Data System (ADS)

    Gloesener, Elodie; Karatekin, Özgür; Dehant, Véronique

    2016-04-01

    MSL Rover Environmental Monitoring Station (REMS) performed high-resolution measurements of temperature and relative humidity during more than one Martian year. In this work, a 1D subsurface model is used to study water vapor exchange between the atmosphere and the subsurface at Gale crater using REMS data. The thermal model used includes several layers of varying thickness with depth and properties that can be changed to correspond to those of Martian rocks at locations studied. It also includes the transport of water vapor through porous Martian regolith and the different phases considered are vapor, ice and adsorbed H2O. The total mass flux is given by the sum of diffusive and advective transport. The role of an adsorbing regolith on water transfer as well as the range of parameters with significant effect on water transport in Martian conditions are investigated. In addition, kinetics of the adsorption process is considered to examine its influence on the water vapor exchange between the subsurface and the atmosphere.

  12. Application of photoacoustic and photothermal techniques for heat conduction measurements in a free-standing chemical vapor-deposited diamond film

    SciTech Connect

    Glorieux, C.; De Groote, J.; Lauriks, W.; Thoen, J. ); Fivez, J. EHSAL, Brussel Universitaire Faculteiten St. Ignatius, Antwerpen )

    1993-11-01

    Heat conduction in a free-standing chemical vapor-deposited polycrystalline diamond film has been investigated by means of combined front and rear photoacoustic signal detection techniques and also by means of a mirage' photothermal beam deflection technique. The results obtained with the different techniques are consistent with a value of [alpha] = (5.5 [+-] 0.4) [times] 10[sup [minus]4]m[sup 2][center dot]s[sup [minus]1] for thermal diffusivity, resulting in a value of k -(9.8 [+-] 0.7) [times] 10[sup 2]W m[sup [minus]1]. K[sup [minus]1] for thermal conductivity when literature values for the density and heat capacity for natural diamond are used. 25 refs., 7 figs.

  13. Constraining Water Vapor Abundance on Mars using a Coupled Heat-Water Transport Model and Seasonal Frost Observations

    NASA Astrophysics Data System (ADS)

    Bapst, J.; Byrne, S.

    2016-12-01

    The stability of water ice on Mars' surface is determined by its temperature and the density of water vapor at the bottom of the atmosphere. Multiple orbiting instruments have been used to study column-integrated water abundance in the martian atmosphere, resolving the global annual water cycle. However, poor knowledge of the vertical distribution of water makes constraining its abundance near the surface difficult. One must assume a mixing regime to produce surface vapor density estimates. More indirectly, one can use the appearance and disappearance of seasonal water frost, along with ice stability models, to estimate this value. Here, we use derived temperature and surface reflectance data from MGS TES to constrain a 1-D thermal diffusion model, which is coupled to an atmospheric water transport model. TES temperatures are used to constrain thermal properties of our modeled subsurface, while changes in TES albedo can be used to determine the timing of water frost. We tune the density of water vapor in the atmospheric model to match the observed seasonal water frost timing in the northern hemisphere, poleward of 45°N. Thus, we produce a new estimate for the water abundance in the lower atmosphere of Mars and how it varies seasonally and geographically. The timing of water frost can be ambiguous in TES data, especially at lower latitudes where the albedo contrast between frosted and unfrosted surfaces is lower (presumably due to lesser areal coverage of water frost). The uncertainty in frost timing with our approach is <20° LS ( 40 sols), and will be used to define upper and lower bounds in our estimate of vapor density. The implications of our derived vapor densities on the stability of surface and subsurface water ice will be discussed.

  14. Studies of Heat Transfer in Complex Internal Flows.

    DTIC Science & Technology

    1984-04-01

    a secondary flow in the form of corkscrew -like vortices which are superposed on the mainflow. Thus, the presence of the bend causes the flow that is...point the transition from a square to a circular cross section occurs. The heat exchanger tubes were modeled by solid cylinders fabricated from drill rod...later, the generator induced the swirl by means of 224 holes drilled through the wall of a circular cylinder (i.e., the swirl chamber) so as to be

  15. How to Compute Complex Interconnected District Heating Systems,

    DTIC Science & Technology

    1980-03-01

    valid modelling of such systems. 3. Network Hydraulic Characteristics In hot water networks the usual pipe diameters, roughnesses, and flow rates are...with cold water network flow characteristics, are shown in Table 2 and Figure 2. Table 2. Characteristic flow values of water distribution networks...conveyance costs decrease. V󈨋 ....... Figure 2. Flow domains for water networks and district heating system networks cold water I//I//I hot water

  16. Numerical simulation of water injection into vapor-dominated reservoirs

    SciTech Connect

    Pruess, K.

    1995-01-01

    Water injection into vapor-dominated reservoirs is a means of condensate disposal, as well as a reservoir management tool for enhancing energy recovery and reservoir life. We review different approaches to modeling the complex fluid and heat flow processes during injection into vapor-dominated systems. Vapor pressure lowering, grid orientation effects, and physical dispersion of injection plumes from reservoir heterogeneity are important considerations for a realistic modeling of injection effects. An example of detailed three-dimensional modeling of injection experiments at The Geysers is given.

  17. Senstitivity analysis of horizontal heat and vapor transfer coefficients for a cloud-topped marine boundary layer during cold-air outbreaks. M.S. Thesis

    NASA Technical Reports Server (NTRS)

    Chang, Y. V.

    1986-01-01

    The effects of external parameters on the surface heat and vapor fluxes into the marine atmospheric boundary layer (MABL) during cold-air outbreaks are investigated using the numerical model of Stage and Businger (1981a). These fluxes are nondimensionalized using the horizontal heat (g1) and vapor (g2) transfer coefficient method first suggested by Chou and Atlas (1982) and further formulated by Stage (1983a). In order to simplify the problem, the boundary layer is assumed to be well mixed and horizontally homogeneous, and to have linear shoreline soundings of equivalent potential temperature and mixing ratio. Modifications of initial surface flux estimates, time step limitation, and termination conditions are made to the MABL model to obtain accurate computations. The dependence of g1 and g2 in the cloud topped boundary layer on the external parameters (wind speed, divergence, sea surface temperature, radiative sky temperature, cloud top radiation cooling, and initial shoreline soundings of temperature, and mixing ratio) is studied by a sensitivity analysis, which shows that the uncertainties of horizontal transfer coefficients caused by changes in the parameters are reasonably small.

  18. Application of a bubble column for evaporative cooling and a simple procedure for determining the latent heat of vaporization of aqueous salt solutions.

    PubMed

    Francis, M J; Pashley, R M

    2009-07-09

    In this work we have studied the evaporative cooling effect produced in a continuous flow air bubble column, containing water and salt solutions. We have established that, at equilibrium, a significant reduction in temperature is produced in an insulated, continuous flow, bubble column. For example, with a continuous flow of inlet air at 22 degrees C, a water bubble column cools to about 8 degrees C, at steady state equilibrium. The cooling effect observed in a continuous bubble column of concentrated aqueous salt solution could be used for commercial applications, such as for evaporative cooling systems. We have developed a simple method, based on the steady state thermal energy balance developed in a bubble column, to determine the latent heat of vaporization of the liquid in the column. Only the equilibrium temperature of the bubble column, the temperature of the inlet gas and the hydrostatic pressure across the column need to be measured. This analysis has been used to determine the heat of vaporization for water and some concentrated salt solutions.

  19. Stratified vapor generator

    DOEpatents

    Bharathan, Desikan [Lakewood, CO; Hassani, Vahab [Golden, CO

    2008-05-20

    A stratified vapor generator (110) comprises a first heating section (H.sub.1) and a second heating section (H.sub.2). The first and second heating sections (H.sub.1, H.sub.2) are arranged so that the inlet of the second heating section (H.sub.2) is operatively associated with the outlet of the first heating section (H.sub.1). A moisture separator (126) having a vapor outlet (164) and a liquid outlet (144) is operatively associated with the outlet (124) of the second heating section (H.sub.2). A cooling section (C.sub.1) is operatively associated with the liquid outlet (144) of the moisture separator (126) and includes an outlet that is operatively associated with the inlet of the second heating section (H.sub.2).

  20. Thin films of metal oxides grown by chemical vapor deposition from volatile transition metal and lanthanide metal complexes

    NASA Astrophysics Data System (ADS)

    Pollard, Kimberly Dona

    1998-08-01

    This thesis describes the synthesis and characterization of novel volatile metal-organic complexes for the chemical vapor deposition (CVD) of metal oxides. Monomeric tantalum complexes, lbrack Ta(OEt)sb4(beta-diketonate)) are prepared by the acid-base reaction of lbrack Tasb2(OEt)sb{10}rbrack with a beta-diketone, (RC(O)CHsb2C(O)Rsp' for R = CHsb3, Rsp' = CFsb3; R = Rsp'=C(CHsb3)sb3; R = Csb3Fsb7,\\ Rsp'=C(CHsb3)sb3;\\ R=Rsp'=CFsb3; and R = Rsp' = CHsb3). The products are characterized spectroscopically. Thermal CVD using these complexes as precursors gave good quality Tasb2Osb5 thin films which are characterized by XPS, SEM, electrical measurements, and XRD. Factors affecting the film deposition such as the type of carrier gas and the temperature of the substrate were considered. Catalyst-enhanced CVD reactions with each of the precursors and a palladium catalyst, ((2-methylallyl)Pd(acac)), were studied as a lower temperature route to good quality Tasb2Osb5 films. The decomposition mechanism at the hot substrate surface was studied. Precursors for the formation of yttria by CVD were examined. New complexes of the form (Y(hfac)sb3(glyme)), (hfac = \\{CFsb3C(O)CHC(O)CFsb3\\}sp-,\\ glyme=CHsb3O(CHsb2CHsb2O)sb{n}CHsb3 for n = 1-4) were synthesized and characterized spectroscopically. X-ray structural determinations of three new complexes were obtained. CVD reaction conditions were determined which give YOF films and, with catalyst-enhanced CVD, reaction conditions which give selective formation of Ysb2Osb3, YOF, or YFsb3. The films were studied by XPS, SEM, and XRD. Decomposition mechanisms which lead to film formation, together with a possible route for fluorine atom transfer from the ligand to the metal resulting in fluorine incorporation, were studied by analysis of exhaust products using GC-MS. Novel precursors of the form lbrack Ce(hfac)sb3(glyme)rbrack,\\ (hfac=\\{CFsb3C(O)CHC(O)CFsb3\\}sp-,\\ glyme=CHsb3O(CHsb2CHsb2O)sb{n}CHsb3, n = 1-4) for CVD of ceria were

  1. Report of results of the vapor vacuum extraction test at the Radioactive Waste Management Complex (RWMC) on the Idaho National Engineering Laboratory (INEL) in the state of Idaho

    SciTech Connect

    Chatwin, T.D.; Miyasaki, D.H.; Sisson, J.B.; Sondrup, A.J.

    1992-01-01

    A test-scale vapor vacuum extraction (VVE) system was installed and operated at the Radioactive Waste Management Complex (RWMC) on the Idaho National Engineering Laboratory (INEL), which is west of Idaho Falls, Idaho and is managed by the US Department of Energy Idaho Field Office. The system was constructed for the purpose of demonstrating the feasibility of VVE or vapor venting technology to abate a volatile organic compound (VOC) plume located in the vadose zone below the subsurface disposal area at the complex. To date, the system has been operated for two periods, a two-week test and a four-month test. The purpose of the two-week test was to determine what would be extracted from the borehole and to verify the design of the system to handle what would be extracted.

  2. Preparation of AlGaN/GaN Heterostructures on Sapphire Using Light Radiation Heating Metal-Organic Chemical Vapor Deposition at Low Pressure

    NASA Astrophysics Data System (ADS)

    Zhou, Yu-Gang; Shen, Bo; Zhang, Rong; Li, Wei-Ping; Chen, Peng; Chen, Zhi-Zhong; Gu, Shu-Lin; Shi, Yi; Z, Huang C.; Zheng, You-Dou

    2000-08-01

    AlGaN/GaN heterostructures on sapphire substrate were fabricated by using light radiation heating metalorganic chemical vapor deposition. Photoluminescence excitation spectra show that there are two abrupt slopes corresponding to the absorption edges of AlGaN and GaN, respectively. X-ray diffraction spectra clearly exhibit the GaN (0002), (0004), and AlGaN (0002), (0004) diffraction peaks, and no diffraction peak other than those from the GaN {0001} and AlGaN {0001} planes is found. Reciprocal space mapping indicates that there is no tilt between the AlGaN layer and the GaN layer. All results also indicate that the sample is of sound quality and the Al composition in the AlGaN layer is of high uniformity.

  3. Numerical modeling of conjugate heat transfer on complex geometries with diagonal Cartesian method. Part 1: Methods

    SciTech Connect

    Lin, W.L.; Carlson, K.D.; Chen, C.J. |

    1999-05-01

    In this study, a diagonal Cartesian method for thermal analysis is developed for simulation of conjugate heat transfer over complex boundaries. This method uses diagonal line segments in addition to Cartesian coordinates. The velocity fields are also modeled using the diagonal Cartesian method. The transport equations are discretized with the finite analytic (FA) method. The current work is validated by simulating a rotated lid-driven cavity flow with conjugate heat transfer, and accurate results are obtained.

  4. Anharmonic effects and heat transport in complex systems (Invited)

    NASA Astrophysics Data System (ADS)

    Wentzcovitch, R. M.

    2013-12-01

    We have recently developed a hybrid strategy combining first principles molecular dynamics (MD) with vibrational normal mode analysis to obtain anharmonic frequency shifts and lifetimes of phonon quasi-particles. This approach is effective irrespective of crystal structure complexity and has been used to investigate anharmonicity in MgSiO3-perpovskite (MgPv) and cubic CaSiO3-perovskite (CaPv). The first is weakly anharmonic but has well identified temperature induced anharmonic Raman frequency shifts, while the second is strongly anharmonic. This method displays fine predictive capability by reproducing subtle measured effects in MgPv and proves to be robust and capable of handling soft phonon anharmonicity in CaPv. This strategy also facilitates calculation of anharmonic phonon dispersions throughout the Brillouin zone. Combination of analytical treatments of anharmonic free energy based on the phonon gas model (PGM) with thoroughly sampled anharmonic dispersions should improve considerably the accuracy of first-principles free energy calculations in crystalline solids at very high temperatures. This method also enables calculations of thermal conductivity, κ, using Boltzman transport equation with lifetimes calculated by MD. This is essential to predict thermodynamics properties and κ by first principles at very high temperatures. Research in collaboration with Tao Sun and Dong-Bo Zhang and supported by NSF award EAR-1019853.

  5. Complex Geometry Creation and Turbulent Conjugate Heat Transfer Modeling

    SciTech Connect

    Bodey, Isaac T; Arimilli, Rao V; Freels, James D

    2011-01-01

    The multiphysics capabilities of COMSOL provide the necessary tools to simulate the turbulent thermal-fluid aspects of the High Flux Isotope Reactor (HFIR). Version 4.1, and later, of COMSOL provides three different turbulence models: the standard k-{var_epsilon} closure model, the low Reynolds number (LRN) k-{var_epsilon} model, and the Spalart-Allmaras model. The LRN meets the needs of the nominal HFIR thermal-hydraulic requirements for 2D and 3D simulations. COMSOL also has the capability to create complex geometries. The circular involute fuel plates used in the HFIR require the use of algebraic equations to generate an accurate geometrical representation in the simulation environment. The best-estimate simulation results show that the maximum fuel plate clad surface temperatures are lower than those predicted by the legacy thermal safety code used at HFIR by approximately 17 K. The best-estimate temperature distribution determined by COMSOL was then used to determine the necessary increase in the magnitude of the power density profile (PDP) to produce a similar clad surface temperature as compared to the legacy thermal safety code. It was determined and verified that a 19% power increase was sufficient to bring the two temperature profiles to relatively good agreement.

  6. Boiler for generating high quality vapor

    NASA Technical Reports Server (NTRS)

    Gray, V. H.; Marto, P. J.; Joslyn, A. W.

    1972-01-01

    Boiler supplies vapor for use in turbines by imparting a high angular velocity to the liquid annulus in heated rotating drum. Drum boiler provides a sharp interface between boiling liquid and vapor, thereby, inhibiting the formation of unwanted liquid droplets.

  7. The effect of saturated steam vapor temperature on heat consumption in the process of color modification of acacia wood

    NASA Astrophysics Data System (ADS)

    Dzurenda, Ladislav

    2017-09-01

    This paper presents the heat consumption on the process of colour modification of acacia timber with measures 30 x 55 x 500 mm in pressure autoclaves AZ 240 using saturated water steam with temperatures from t = 110 to 140 °C following the regimes of colour homogenisation of I., II. and III. degree. The dependance of the heat consumption normative QTFS on the temparature of saturated water steam in the process of colour homogenisation of acacia timber following these regimes describes the equation: QTFS = 1.1122.t -13.903 kWh.m-3.

  8. Vapor generator wand

    NASA Technical Reports Server (NTRS)

    Robelen, David B. (Inventor)

    1994-01-01

    In low speed wind tunnels it is often desirable to visualize airflow to augment observations made with instruments such as strain and pressure gages. Current technology devices for delivery of a vapor are bulky and thus disrupt local airflow. It is the object of this invention to provide a device capable of delivering a stream of vapor with a minimal effect on local airflow. The present invention achieves this object by utilizing a narrow tube as a heating device for producing the vapor. Running an electrical current through the tube provides resistive heating to a liquid which produces a vapor when boiled. As the entire heating and delivery portion of the device is simply a small cylinder the disruption to airflow within the tunnel is minimized. this allows an experimenter to place the source of vapor fairly close to a model without causing too much change to the model data. The novelty of the present invention lies in reducing the bulk of current technology devices by combining the acts of heating and delivery.

  9. A dual response organogel system based on an iridium complex and a Eu(iii) hybrid for volatile acid and organic amine vapors.

    PubMed

    Cao, Xinhua; Zhao, Na; Zou, Guodong; Gao, Aiping; Ding, Qianqian; Zeng, Guanjie; Wu, Yongquan

    2017-05-24

    A thiophene-based hybrid organogel system consisting of complex iridium (Ir) and EuCl3·6H2O was designed and synthesized to realize dual responses to volatile acids and organic amine vapors. The photophysical properties and self-assembly of compound 1 and the hybrid organogel were also studied. Compound 1 could gelate some organic solvents and self-assemble into 3D nanofibers in the gels. The stable hybrid organogel 1-Ir-Eu could be obtained after addition of complex Ir and EuCl3·6H2O. FTIR spectral results showed that the hydrogen bond still remained even upon addition of complex Ir, EuCl3·6H2O, NaOH and CF3COOH to organogel 1. Interestingly, the emission properties of the hybrid organogel 1-Ir-Eu could undergo interconversion between cyan light and red light via addition of NaOH and CF3COOH. The emission properties of xerogel film 1-Ir-Eu obtained in the presence of NaOH could also undergo fast and reversible transition in response to volatile acids such as CF3COOH, formic acid, acetic acid, propionic acid and organic amine vapors such as ammonium hydroxide, Et3N, tripropylamine, and ethylenediamine. The emission spectral change of Ir-Eu in the organogel or xerogel in the presence of base and acid demonstrated the formation of a new complex between complex Ir and EuCl3·6H2O. This dual-response process could be repeated many times. Contact angle experiment results further showed the morphology and internal components of the xerogel film surface in the process of response to gaseous CF3COOH and Et3N. This work provides a method for producing multifunctional supramolecular materials for sensing volatile acids and organic amine vapors.

  10. Vapor Intrusion

    EPA Pesticide Factsheets

    Vapor intrusion occurs when there is a migration of volatile chemicals from contaminated groundwater or soil into an overlying building. Volatile chemicals can emit vapors that may migrate through subsurface soils and into indoor air spaces.

  11. Force Field Benchmark of Organic Liquids: Density, Enthalpy of Vaporization, Heat Capacities, Surface Tension, Isothermal Compressibility, Volumetric Expansion Coefficient, and Dielectric Constant.

    PubMed

    Caleman, Carl; van Maaren, Paul J; Hong, Minyan; Hub, Jochen S; Costa, Luciano T; van der Spoel, David

    2012-01-10

    The chemical composition of small organic molecules is often very similar to amino acid side chains or the bases in nucleic acids, and hence there is no a priori reason why a molecular mechanics force field could not describe both organic liquids and biomolecules with a single parameter set. Here, we devise a benchmark for force fields in order to test the ability of existing force fields to reproduce some key properties of organic liquids, namely, the density, enthalpy of vaporization, the surface tension, the heat capacity at constant volume and pressure, the isothermal compressibility, the volumetric expansion coefficient, and the static dielectric constant. Well over 1200 experimental measurements were used for comparison to the simulations of 146 organic liquids. Novel polynomial interpolations of the dielectric constant (32 molecules), heat capacity at constant pressure (three molecules), and the isothermal compressibility (53 molecules) as a function of the temperature have been made, based on experimental data, in order to be able to compare simulation results to them. To compute the heat capacities, we applied the two phase thermodynamics method (Lin et al. J. Chem. Phys.2003, 119, 11792), which allows one to compute thermodynamic properties on the basis of the density of states as derived from the velocity autocorrelation function. The method is implemented in a new utility within the GROMACS molecular simulation package, named g_dos, and a detailed exposé of the underlying equations is presented. The purpose of this work is to establish the state of the art of two popular force fields, OPLS/AA (all-atom optimized potential for liquid simulation) and GAFF (generalized Amber force field), to find common bottlenecks, i.e., particularly difficult molecules, and to serve as a reference point for future force field development. To make for a fair playing field, all molecules were evaluated with the same parameter settings, such as thermostats and barostats

  12. Force Field Benchmark of Organic Liquids: Density, Enthalpy of Vaporization, Heat Capacities, Surface Tension, Isothermal Compressibility, Volumetric Expansion Coefficient, and Dielectric Constant

    PubMed Central

    2011-01-01

    The chemical composition of small organic molecules is often very similar to amino acid side chains or the bases in nucleic acids, and hence there is no a priori reason why a molecular mechanics force field could not describe both organic liquids and biomolecules with a single parameter set. Here, we devise a benchmark for force fields in order to test the ability of existing force fields to reproduce some key properties of organic liquids, namely, the density, enthalpy of vaporization, the surface tension, the heat capacity at constant volume and pressure, the isothermal compressibility, the volumetric expansion coefficient, and the static dielectric constant. Well over 1200 experimental measurements were used for comparison to the simulations of 146 organic liquids. Novel polynomial interpolations of the dielectric constant (32 molecules), heat capacity at constant pressure (three molecules), and the isothermal compressibility (53 molecules) as a function of the temperature have been made, based on experimental data, in order to be able to compare simulation results to them. To compute the heat capacities, we applied the two phase thermodynamics method (Lin et al. J. Chem. Phys.2003, 119, 11792), which allows one to compute thermodynamic properties on the basis of the density of states as derived from the velocity autocorrelation function. The method is implemented in a new utility within the GROMACS molecular simulation package, named g_dos, and a detailed exposé of the underlying equations is presented. The purpose of this work is to establish the state of the art of two popular force fields, OPLS/AA (all-atom optimized potential for liquid simulation) and GAFF (generalized Amber force field), to find common bottlenecks, i.e., particularly difficult molecules, and to serve as a reference point for future force field development. To make for a fair playing field, all molecules were evaluated with the same parameter settings, such as thermostats and barostats

  13. Complex Nonmetallic Inclusions Formed in Billets Heated for Rolling and Characteristics of Structural Steels

    NASA Astrophysics Data System (ADS)

    Zaitsev, A. I.; Koldaev, A. V.; Arutyunyan, N. A.; Shaposhnikov, N. G.; Dunaev, S. F.

    2017-03-01

    Complex bimetallic inclusions formed in billets from steels 09G2S and K52 during heating for rolling are studied by methods of electron microscopy and local x-ray spectrum analysis. To check the established evolution of oxide inclusions based on aluminomagnesium spinel and other oxide compositions, individual inclusions of manganese sulfide and complex oxide-sulfide inclusions, a method developed by the Severstal'Company and the Karpov NIFKhI for determining the content of corrosion-active nonmetallic inclusions (CANI) as a function of the heating mode is applied to the steels studied. It is recommended to increase the temperature and duration of heating of billets for hot rolling in order to lower the content of CANI and to raise the resistance of the steels to local corrosion.

  14. Complex of automated equipment and technologies for waveguides soldering using induction heating

    NASA Astrophysics Data System (ADS)

    Murygin, A. V.; Tynchenko, V. S.; Laptenok, V. D.; Emilova, O. A.; Bocharov, A. N.

    2017-02-01

    The article deals with the problem of designing complex automated equipment for soldering waveguides based on induction heating technology. A theoretical analysis of the problem, allowing to form a model of the «inductor-waveguide» system and to carry out studies to determine the form of inducing wire, creating a narrow and concentrated heat zone in the area of the solder joint. Also solves the problem of the choice of the temperature control means, the information from which is used later to generate the effective management of induction soldering process. Designed hardware complex in conjunction with the developed software system is a system of automatic control, allowing to manage the process of induction heating, to prevent overheating and destruction of the soldered products, improve the stability of induction soldering process, to improve the quality of products, thereby reducing time and material costs for the production.

  15. Simplifying the model of a complex heat-transfer system for solving the relay control problem

    NASA Astrophysics Data System (ADS)

    Shilin, A. A.; Bukreev, V. G.

    2014-09-01

    A method for approximating the high-dimensionality model of a complex heat-transfer system with time delay by a nonlinear second-order differential equation is proposed. The modeling results confirming adequacy of the nonlinear properties of the reduced and initial models and their correspondence to the controlled plant actual data are presented.

  16. REFRIG-12: A graphics-augmented interactive program for designing vapor-compression refrigeration/heat pump cycles

    NASA Astrophysics Data System (ADS)

    Davis, B. W.

    1984-09-01

    REFRIG-12 is an interactive program that serves as a tool for designing and analyzing thermodynamic vapor compression refrigeration/heatpump cycles. Graphic and alphanumeric responses to design decisions are displayed simultaneously on separate monitors. Temperature-Entropy property coordinates are used to describe the thermodynamic processes Freon-12 undergoes as it passes through the various mechanical components which ultimately produce the cycle. The processes are displayed graphically as the user makes the decisions to design a refrigeration cycle. When a design has been completed, REFRIG-12 offers the user an opportunity to make changes. The effects of design changes become graphically discernible through successive overlays on the graphics monitor. DOTPLOT can be executed to produce a hard copy of the graphics monitor display. Summaries of the cycle performance, pertinent energy transfers, and other engineering consequences of the design specifications can also be presented - at user option - on both the CRT and the printer. REFRIG-12 is organized so that a relatively small main program controls 25 subroutines. Each subroutine has stand alone characteristics and may be used with programs having other primary purposes. The subroutines can be conveniently merged (or chained) into system memory as needed.

  17. Vapor-liquid activity coefficients for methanol and ethanol from heat of solution data: application to steam-methane reforming.

    PubMed

    Kunz, R G; Baade, W F

    2001-11-16

    This paper presents equations and curves to calculate vapor-liquid phase equilibria for methanol and ethanol in dilute aqueous solution as a function of temperature, using activity coefficients at infinite dilution. These thermodynamic functions were originally derived to assess the distribution of by-product contaminants in the process condensate and the steam-system deaerator of a hydrogen plant [Paper ENV-00-171 presented at the NPRA 2000 Environmental Conference, San Antonio, TX, 10-12 September 2000], but have general applicability to other systems as well. The functions and calculation method described here are a necessary piece of an overall prediction technique to estimate atmospheric emissions from the deaerator-vent when the process condensate is recycled as boiler feed water (BFW) make-up. Having such an estimation technique is of particular significance at this time because deaerator-vent emissions are already coming under regulatory scrutiny in California [Emissions from Hydrogen Plant Process Vents, Adopted 21 January 2000] followed closely elsewhere in the US, and eventually worldwide. The overall technique will enable a permit applicant to estimate environmental emissions to comply with upcoming regulations, and a regulatory agency to evaluate those estimates. It may also be useful to process engineers as a tool to estimate contaminant concentrations and flow rates in internal process streams such as the steam-generating system. Metallurgists and corrosion engineers might be able to use the results for materials selection.

  18. Heat- and light-induced detachment of the light harvesting complex from isolated photosystem I supercomplexes.

    PubMed

    Nellaepalli, Sreedhar; Zsiros, Ottó; Tóth, Tünde; Yadavalli, Venkateswarlu; Garab, Győző; Subramanyam, Rajagopal; Kovács, László

    2014-08-01

    In a previous study, using photosystem I enriched stroma thylakoid membrane vesicles, we have shown that the light harvesting complexes of this photosystem are prone to heat- and light-induced, thermo-optically driven detachment from the supercomplex [43]. We have also shown that the splitting of the supercomplex occurs in a gradual and specific manner, selectively affecting the different constituents of the antenna complexes. Here we further analyse these heat- and light-induced processes in isolated Photosystem I supercomplex using circular dichroism and 77K fluorescence emission spectroscopy and immuno blotting, and obtain further details on the sequence of events of the dissociation process as well as on the thermal stability of the different components. Our absorption and circular dichroism spectroscopy and immuno blotting data show that the dissociation of LHCI from PSI-LHCI supercomplex starts above 50°C. Also, the low temperature fluorescence emission spectra depicts decrease of maximum fluorescence emission at 730nm and an increase of the intensity at 685nm, and about 10nm blue-shifts, from 730 to 720nm and from 685 to 676nm, respectively, indicating the heat (50°C) induced detachment of LHCI from PSI core complexes. The reaction centre proteins are highly stable even at high temperatures. Lhca2 is more heat stable than the other light harvesting protein complexes of PSI, whereas Lhca4 and Lhca3 are rather labile. Combined heat and light treatments significantly enhances the disorganization of PSI-LHCI supercomplexes, indicating a thermo-optic mechanism, which might have significant role under combined heat and light stress conditions. Copyright © 2014 Elsevier B.V. All rights reserved.

  19. The Water Vapor Spectrum of APM 08279+5255: X-Ray Heating and Infrared Pumping over Hundreds of Parsecs

    NASA Astrophysics Data System (ADS)

    Bradford, C. M.; Bolatto, A. D.; Maloney, P. R.; Aguirre, J. E.; Bock, J. J.; Glenn, J.; Kamenetzky, J.; Lupu, R.; Matsuhara, H.; Murphy, E. J.; Naylor, B. J.; Nguyen, H. T.; Scott, K.; Zmuidzinas, J.

    2011-11-01

    We present the rest-frame 200-320 μm spectrum of the z = 3.91 quasar APM 08279+5255, obtained with Z-Spec at the Caltech Submillimeter Observatory. In addition to the J = 8 → 7 to J = 13 → 12 CO rotational transitions which dominate the CO cooling, we find six transitions of water originating at energy levels ranging up to 643 K. Most are first detections at high redshift, and we have confirmed one transition with CARMA. The CO cooling is well described by our X-ray dominated region (XDR) model, assuming L 1-100 keV ~ 1 × 1046 erg s-1, and that the gas is distributed over a 550-pc size scale, as per the now-favored μ = 4 lensing model. The total observed cooling in water corresponds to 6.5 × 109 L sun, comparable to that of CO. We compare the water spectrum with that of Mrk 231, finding that the intensity ratios among the high-lying lines are similar, but with a total luminosity scaled up by a factor of ~50. Using this scaling, we estimate an average water abundance relative to H2 of 1.4 × 10-7, a good match to the prediction of the chemical network in the XDR model. As with Mrk 231, the high-lying water transitions are excited radiatively via absorption in the rest-frame far-infrared, and we show that the powerful dust continuum in APM 08279+5255 is more than sufficient to pump this massive reservoir of warm water vapor.

  20. Tubing For Sampling Hydrazine Vapor

    NASA Technical Reports Server (NTRS)

    Travis, Josh; Taffe, Patricia S.; Rose-Pehrsson, Susan L.; Wyatt, Jeffrey R.

    1993-01-01

    Report evaluates flexible tubing used for transporting such hypergolic vapors as those of hydrazines for quantitative analysis. Describes experiments in which variety of tubing materials, chosen for their known compatibility with hydrazine, flexibility, and resistance to heat.

  1. Numerical modeling of simultaneous heat and moisture transfer under complex geometry for refrigeration purposes

    NASA Astrophysics Data System (ADS)

    Hou, Xiaofei; Joaquim, Rigola; Oriol, Lehmkuhl; Carles, Oliet; D, Pérez-Segarra Carlos

    2012-11-01

    The aim of the paper is to gain a better insight into heat and moisture transfer in refrigerator and to do fundamental study for water evaporation and condensation in refrigeration application. The governing transport equations (continuity, momentum, energy and concentration equations) in 3D Cartesian coordinates are firstly introduced. As the mixed convection is simulated in the paper, buoyancy forces caused by both temperature and concentration gradient are considered and are also included in momentum equation. Numerical results are carried out by using Termofluids code. The pressure-velocity linkage is solved by means of an explicit finite volume fractional step procedure. In order to validate the code, a humid air flowing in a horizontal 3D rectangular duct case is carried out and compared with the published numerical and experimental results. The contour of temperature and vapor density of air at a cross section is provided and analyzed. Finally, the heat and mass transfer process during the moist air flow through complicated geometry is simulated and temperature and humidity distributions are obtained.

  2. Device Quality SiO2 Deposited by Distributed Electron Cyclotron Resonance Plasma Enhanced Chemical Vapor Deposition without Substrate Heating

    NASA Astrophysics Data System (ADS)

    Jiang, Nan; Hugon, Marie-Christine; Agius, Bernard; Kretz, Thierry; Plais, François; Pribat, Didier; Carriere, Thierry; Puech, Michel

    1992-10-01

    The deposition of high electrical quality SiO2 films on Si wafers has been achieved without substrate heating, (T<˜ 100°C), using distributed electron cyclotron resonance (DECR) microwave plasmas. We have studied the effects of the reactant gas mixture composition (O2/SiH4) on the dielectric behavior of DECR SiO2. The electrical performances of both Si-SiO2 interfaces and SiO2 films in metal-oxide-semiconductor (MOS) structures were assessed by several characterization methods including critical field (Ec) evaluation, fixed charge densities (Qox) and interface traps densities (Dit) determinations. We report typical values of Ec around 6 MV\\cdotcm-1, and Qox and Dit densities around 2× 1010 cm-2 and 3× 1010 cm-2\\cdoteV-1 respectively. Thin film SOI-MOSFETs have also been fabricated to prove the DECR oxide quality.

  3. TRANSPORT OF HEAT, WATER VAPOR AND CARBON DOXIDE BY LONG PERIOD EDDIES IN THE STABLE BOUNDARY LAYER

    SciTech Connect

    Kurzeja, R.

    2010-07-26

    The vertical transport of heat and trace chemicals for a night in April has been studied with a wavelet analysis and conventional one-hour averages. It was found that for the night of April 20, 2009, turbulent kinetic energy, heat and trace chemicals were transported directed downward from the jet core. The most significant periods for this transport were less than 5 minutes and greater than one hour with intermittent transport taking place in the 5 min to 1 hour time frame. The nocturnal boundary layer is characterized by turbulent intermittency, long period oscillations, and a slow approach to equilibrium, (Mahrt, 1999). Although turbulence is usually maintained by surface friction, downward transport from low-level jets can also play an important role in turbulence maintenance and in the transport of scalars, Mahrt (1999), Banta et al. (2006). The eddy covariance flux measurement technique assumes continuous turbulence which is unusual in the stable boundary because significant flux transport occurs via turbulent eddies whose periods are long compared with the averaging time (Goulden et al., 1996). Systematic error in eddy flux measurements is attributed mainly to the neglect of long period eddies. Banta et al. (2006) noted that observations of turbulence below the low level jet suggested that while upward transport of turbulence kinetic energy (TKE) is common, downward transport from the jet can also occur. They found that in the CASES 99 experiments that turbulence scaled well with the strength of the low-level jet, and that surface cooling was more important than surface roughness. Because nocturnal turbulence is intermittent and non-stationary, the appropriate averaging time for calculation of TKE and EC fluxes is not obvious. Wavelet analysis is, thus, a more suitable analysis tool than conventional Fourier analysis.

  4. Heat inactivation of Mycobacterium avium-Mycobacterium intracellulare complex organisms in meat products.

    PubMed Central

    Merkal, R S; Crawford, J A; Whipple, D L

    1979-01-01

    Wieners and sausages were prepared which contained the most heat-tolerant representative of the Mycobacterium avium-Mycobacterium intracellulare complex we were able to obtain. They also were prepared with infected tissues obtained from tuberculous swine. Processing conditions were as varied as possible. Neither incorporation of sodium nitrite in the emulsion nor presence of smoke during processing altered the heat susceptibility of the organisms. Substantial killing of the organisms occurred as wieners reached the upper processing temperatures, but hot oil or radiant heating of the "precooked" sausages allowed very short times within the killing range; hence, higher peak internal temperatures were necessary. The lethalities for these organisms of reaching and maintaining various processing temperatures are given. PMID:575610

  5. Study on the effect of heat treatment conditions on metalorganic-chemical-vapor-deposited ferroelectric Hf0.5Zr0.5O2 thin film on Ir electrode

    NASA Astrophysics Data System (ADS)

    Shimizu, Takao; Yokouchi, Tatsuhiko; Shiraishi, Takahisa; Oikawa, Takahiro; Sankara Rama Krishnan, P. S.; Funakubo, Hioshi

    2014-09-01

    The effect of the heat treatment conditions on the constituent phases and electrical properties of (Hf0.5Zr0.5)O2 films deposited by the metalorganic chemical vapor deposition was investigated. By using a low temperature or short duration for post-heat treatment after the deposition, the volume fraction of the tetragonal phase increases, resulting in a high dielectric constant. On the other hand, the volume fraction of the monoclinic phase increased in the films that were heat-treated at higher temperatures and exposed to longer heat treatment duration. The ferroelectric with and dielectric properties of these films were greatly inferior. Superior ferroelectric properties a significant volume fraction of orthorhombic phase were achieved for intermediate heat treatment conditions. These results give useful information to understand the origin of the ferroelectricity and to control the phases and electrical properties in HfO2-based films.

  6. Dynamic Complexity Study of Nuclear Reactor and Process Heat Application Integration

    SciTech Connect

    J'Tia Patrice Taylor; David E. Shropshire

    2009-09-01

    Abstract This paper describes the key obstacles and challenges facing the integration of nuclear reactors with process heat applications as they relate to dynamic issues. The paper also presents capabilities of current modeling and analysis tools available to investigate these issues. A pragmatic approach to an analysis is developed with the ultimate objective of improving the viability of nuclear energy as a heat source for process industries. The extension of nuclear energy to process heat industries would improve energy security and aid in reduction of carbon emissions by reducing demands for foreign derived fossil fuels. The paper begins with an overview of nuclear reactors and process application for potential use in an integrated system. Reactors are evaluated against specific characteristics that determine their compatibility with process applications such as heat outlet temperature. The reactor system categories include light water, heavy water, small to medium, near term high-temperature, and far term high temperature reactors. Low temperature process systems include desalination, district heating, and tar sands and shale oil recovery. High temperature processes that support hydrogen production include steam reforming, steam cracking, hydrogen production by electrolysis, and far-term applications such as the sulfur iodine chemical process and high-temperature electrolysis. A simple static matching between complementary systems is performed; however, to gain a true appreciation for system integration complexity, time dependent dynamic analysis is required. The paper identifies critical issues arising from dynamic complexity associated with integration of systems. Operational issues include scheduling conflicts and resource allocation for heat and electricity. Additionally, economic and safety considerations that could impact the successful integration of these systems are considered. Economic issues include the cost differential arising due to an integrated

  7. Electrolyte vapor condenser

    DOEpatents

    Sederquist, R.A.; Szydlowski, D.F.; Sawyer, R.D.

    1983-02-08

    A system is disclosed for removing electrolyte from a fuel cell gas stream. The gas stream containing electrolyte vapor is supercooled utilizing conventional heat exchangers and the thus supercooled gas stream is passed over high surface area passive condensers. The condensed electrolyte is then drained from the condenser and the remainder of the gas stream passed on. The system is particularly useful for electrolytes such as phosphoric acid and molten carbonate, but can be used for other electrolyte cells and simple vapor separation as well. 3 figs.

  8. Hsp56: a novel heat shock protein associated with untransformed steroid receptor complexes.

    PubMed

    Sanchez, E R

    1990-12-25

    The recently-described p59 protein has been shown to be associated with untransformed steroid receptors present in rabbit uterus and rat liver cytosols (Tai, P. K., Maeda, Y., Nakao, K., Wakim, N. G., Duhring, J. L., and Faber, L. E. (1986) Biochemistry 25, 5269-5275; Renoir, J.-M., Radanyi, C., Faber, L. E., and Baulieu, E.-E. (1990) J. Biol. Chem. 265, 10740-10745), while a smaller version of this protein (p56) interacts with glucocorticoid receptors in human IM-9 cell cytosols (Sanchez, E. R., Faber, L. E., Henzel, W. J., and Pratt, W. B. (1990) Biochemistry 29, 5145-5152). In addition to interacting with glucocorticoid receptors, the p56 protein of IM-9 cell cytosol is also found as part of a large heteromeric complex that contains both the 70-kDa and 90-kDa heat shock proteins (hsp70 and hsp90, respectively). Given this association of p56 with the two major stress proteins, I have speculated that p56 may itself be a heat shock protein. In this paper, the effect of heat stress on the rate of synthesis of p56 is determined. Intact IM-9 cells were exposed to 37 or 43 degrees C for 4 h, followed by pulse-labeling with [35S]methionine. Analysis of whole cytosolic extracts by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and autoradiography reveal an increased rate of radiolabeling for hsp70, hsp90, hsp100, ad hsp110, but no heat-inducible protein of smaller relative molecular mass is detected. However, immune-purification of p56 from normal and heat-stressed cytosols with the EC1 monoclonal antibody results in the presence of a 56-kDa protein that exhibits an increased rate of synthesis in response to heat stress. The results of two-dimensional gel Western blots employing the EC1 antibody demonstrate that this heat-inducible protein is indeed the EC1-reactive p56 protein and that the induction effect is not due to unequal yields of p56 during immune-purification. Heat stress has no effect on the composition of the p56.hsp.70.hsp90 complex, except that

  9. Integrated bioenergy complex for the production of power, heat and bio-ethanol

    SciTech Connect

    Taviani, M.; Chiaramonti, D.; Tondi, G.; Grassi, G.

    1998-07-01

    In this paper an integrated bioenergy complex for the production of power, heat and bio-ethanol is presented. Ethanol, in fact, has been recognized as a high-quality transportation fuel. The reduction of petroleum consumption, especially for transport, is a strategic goal especially for those countries that already have or will experience an intensive industrial development in the next future. For these motivations, the production of bio-ethanol from Sweet Sorghum (which is now one of the most promising crop for this application in term of productivity, inputs demand, and flexibility) is of great interest in most of countries. The proposed integrated complex produces power, heat and bio-ethanol: the produced power and heat are partly used for bio-ethanol processing and biomass pre-treatment, partly to be sold to the market. This system has important innovations allowing a decentralized energy and ethanol production and creating new local jobs. The small power plant is based upon a steam cycle with an advanced low emission combustor, capable of burning different biomass resources with a modest decrease in the efficiency value. The Bioenergy Complex, suitable to satisfy the needs of a 3,000 inhabitants village, is composed by the following sub-systems: (1) Sweet Sorghum plantation (250 ha); the main products are: dry bagasse (approximately 3,900 Ton/year), grains (1,300 Ton/y) and sugar (1,850 Ton/y); (2) Cane crushing--sugar juice extraction system; (3) Sugar juice fermentation and distillation ethanol production (approx. 835 Ton/y); (4) Biomass pre-treatment components (grinding, drying, briquetting, storage, etc.); and (5) Cogeneration unit--the expansion unit is constituted by a last generation reciprocating steam engine, coupled with a 500 kWe alternator; the heat of the expanded flow is removed in the condenser, with an available thermal power of approximately 2,000 kWt.

  10. Three-Dimensional Modeling of Fluid and Heat Transport in an Accretionary Complex

    NASA Astrophysics Data System (ADS)

    Paula, C. A.; Ge, S.; Screaton, E. J.

    2001-12-01

    As sediments are scraped off of the subducting oceanic crust and accreted to the overriding plate, the rapid loading causes pore pressures in the underthrust sediments to increase. The change in pore pressure drives fluid flow and heat transport within the accretionary complex. Fluid is channeled along higher permeability faults and fractures and expelled at the seafloor. In this investigation, we examined the effects of sediment loading on fluid flow and thermal transport in the decollement at the Barbados Ridge subduction zone. Both the width and thickness of the Barbados Ridge accretionary complex increase from north to south. The presence of mud diapers south of the Tiburon Rise and an observed southward decrease in heat flow measurements indicate that the increased thickness of the southern Barbados accretionary prism affects the transport of chemicals and heat by fluids. The three-dimensional geometry and physical properties of the accretionary complex were utilized to construct a three-dimensional fluid flow/heat transport model. We calculated the pore pressure change due to a period of sediment loading and added this to steady-state pressure conditions to generate initial conditions for transient simulations. We then examined the diffusion of pore pressure and possible perturbation of the thermal regime over time due to loading of the underthrust sediments. The model results show that the sediment-loading event was sufficient to create small temperature fluctuations in the decollement zone. The magnitude of temperature fluctuation in the decollement was greatest at the deformation front but did not vary significantly from north to south of the Tiburon Rise.

  11. Correlating the Transport of Precipitable Water Vapor with Rainfall in a Complex Orographic Environment Before, During and After a Tropical Storm: Case Study of Typhoon Morakot

    NASA Astrophysics Data System (ADS)

    Almanza, V. D.; Braun, J. J.; Kuo, Y.; Schreiner, W. S.

    2010-12-01

    On August 7, 2009, Typhoon Morakot struck Taiwan producing 1,504 mm of rain in a 24-hour period, and 2874 mm over a 96-h period. The flooding and landslides associated with Typhoon Morakot claimed more than 700 lives and caused major damage in Taiwan. In-situ observations of precipitable water vapor (PWV) from 76 GPS stations and 450 rain gauges operated by the Taiwanese Central Weather Bureau captured the water vapor evolution and rainfall distribution as the storm moved through the island nation. Recently, Fang et al (2010) performed a high-resolution (4-km) simulation of Morakot using the Advanced Weather Research and Forecasting (WRF-ARW) model. This research compared model generated PWV and rainfall to in-situ data to evaluate the performance of the WRF-ARW during the passage of Typhoon Morakot. In general, the model captured time evolution of the water vapor distribution as Typhoon Morakot passed through the island. However, there are also subtle differences. Although the model 96-h accumulated rainfall reproduced many salient features of the orographic precipitatoin, accurate prediction of rainfall evolution at high temporal and spatial resolution proves to be challenging due to complex topography and its interaction with the typhoon circulation. Comparison of PWV observation from the climatology of August 2008 suggests that the pre-typhoon environment is abnormally moist over Taiwan. This might provide an explanation for the extra-ordinary rainfall amount for this case. This study illustrates that the PWV observations from a dense ground-based GPS network, coupled with a rainfall observations from a high-resolution rain gauge network, can be quite valuable in verifying high-resolution model prediction for a significant weather event such as Typhoon Morakot.

  12. Influence of tailored MLI for complex surface geometries on heat transfer

    NASA Astrophysics Data System (ADS)

    Neumann, H.; Mayrhofer, R.; Richter, T.

    2015-12-01

    Complex, non-developable surfaces require a tailored multi-layer insulation (MLI) for lowest heat load. The most experiments showing the heat transfer through MLI are performed under quasi-ideal conditions determining the principle insulation quality. But the surface to be insulated in real cryostats implies feed-throughs and other non-developable surface parts. The thermal performance of MLI is degraded significantly at cutting points. To investigate this degrading effect a LN2-filled cylinder with a diameter of 219 mm and a length of 1820 mm was insulated with MLI and the heat load was measured by means of calorimetry. In addition the heat load to an insulated cylinder with eighteen branches was measured. Both cylinders have the same surface of 1.37 m2 for a comparison of the results. This article describes the experiments with different ways of tailoring the MLI for the cylinder with branches and discusses their results. It was shown that the cutting points at the branches have a significant degrading influence on the thermal performance of MLI.

  13. AMTEC vapor-vapor series connected cells

    NASA Technical Reports Server (NTRS)

    Underwood, Mark L. (Inventor); Williams, Roger M. (Inventor); Ryan, Margaret A. (Inventor); Nakamura, Barbara J. (Inventor); Oconnor, Dennis E. (Inventor)

    1995-01-01

    An alkali metal thermoelectric converter (AMTEC) having a plurality of cells structurally connected in series to form a septum dividing a plenum into two chambers, and electrically connected in series, is provided with porous metal anodes and porous metal cathodes in the cells. The cells may be planar or annular, and in either case a metal alkali vapor at a high temperature is provided to the plenum through one chamber on one side of the wall and returned to a vapor boiler after condensation at a chamber on the other side of the wall in the plenum. If the cells are annular, a heating core may be placed along the axis of the stacked cells. This arrangement of series-connected cells allows efficient generation of power at high voltage and low current.

  14. The lithium vapor box divertor

    NASA Astrophysics Data System (ADS)

    Goldston, R. J.; Myers, R.; Schwartz, J.

    2016-02-01

    It has long been recognized that volumetric dissipation of the plasma heat flux from a fusion power system is preferable to its localized impingement on a material surface. Volumetric dissipation mitigates both the anticipated very high heat flux and intense particle-induced damage due to sputtering. Recent projections to a tokamak demonstration power plant suggest an immense upstream parallel heat flux, of order 20 GW m-2, implying that fully detached operation may be a requirement for the success of fusion power. Building on pioneering work on the use of lithium by Nagayama et al and by Ono et al as well as earlier work on the gas box divertor by Watkins and Rebut, we present here a concept for a lithium vapor box divertor, in which lithium vapor extracts momentum and energy from a fusion-power-plant divertor plasma, using fully volumetric processes. At the high powers and pressures that are projected this requires a high density of lithium vapor, which must be isolated from the main plasma in order to avoid lithium build-up on the chamber walls or in the plasma. Isolation is achieved through a powerful multi-box differential pumping scheme available only for condensable vapors. The preliminary box-wise calculations are encouraging, but much more work is required to demonstrate the practical viability of this scheme, taking into account at least 2D plasma and vapor flows within and between the vapor boxes and out of the vapor boxes to the main plasma.

  15. Vacuum vapor deposition gun assembly

    DOEpatents

    Zeren, Joseph D.

    1985-01-01

    A vapor deposition gun assembly includes a hollow body having a cylindrical outer surface and an end plate for holding an adjustable heat sink, a hot hollow cathode gun, two magnets for steering the plasma from the gun into a crucible on the heat sink, and a shutter for selectively covering and uncovering the crucible.

  16. Vapor generation methods for explosives detection research

    SciTech Connect

    Grate, Jay W.; Ewing, Robert G.; Atkinson, David A.

    2012-12-01

    The generation of calibrated vapor samples of explosives compounds remains a challenge due to the low vapor pressures of the explosives, adsorption of explosives on container and tubing walls, and the requirement to manage (typically) multiple temperature zones as the vapor is generated, diluted, and delivered. Methods that have been described to generate vapors can be classified as continuous or pulsed flow vapor generators. Vapor sources for continuous flow generators are typically explosives compounds supported on a solid support, or compounds contained in a permeation or diffusion device. Sources are held at elevated isothermal temperatures. Similar sources can be used for pulsed vapor generators; however, pulsed systems may also use injection of solutions onto heated surfaces with generation of both solvent and explosives vapors, transient peaks from a gas chromatograph, or vapors generated by s programmed thermal desorption. This article reviews vapor generator approaches with emphasis on the method of generating the vapors and on practical aspects of vapor dilution and handling. In addition, a gas chromatographic system with two ovens that is configurable with up to four heating ropes is proposed that could serve as a single integrated platform for explosives vapor generation and device testing. Issues related to standards, calibration, and safety are also discussed.

  17. Method and apparatus for vapor detection

    NASA Technical Reports Server (NTRS)

    Lerner, Melvin (Inventor); Hood, Lyal V. (Inventor); Rommel, Marjorie A. (Inventor); Pettitt, Bruce C. (Inventor); Erikson, Charles M. (Inventor)

    1980-01-01

    The method disclosed herein may be practiced by passing the vapors to be sampled along a path with halogen vapor, preferably chlorine vapor, heating the mixed vapors to halogenate those of the sampled vapors subject to halogenation, removing unreacted halogen vapor, and then sensing the vapors for organic halogenated compounds. The apparatus disclosed herein comprises means for flowing the vapors, both sample and halogen vapors, into a common path, means for heating the mixed vapors to effect the halogenation reaction, means for removing unreacted halogen vapor, and a sensing device for sensing halogenated compounds. By such a method and means, the vapors of low molecular weight hydrocarbons, ketones and alcohols, when present, such as methane, ethane, acetone, ethanol, and the like are converted, at least in part, to halogenated compounds, then the excess halogen removed or trapped, and the resultant vapors of the halogenated compounds sensed or detected. The system is highly sensitive. For example, acetone in a concentration of 30 parts per billion (volume) is readily detected.

  18. [Some properties of complexes formed by small heat shock proteins with denatured actin].

    PubMed

    Pivovarova, A V; Chebotareva, N A; Guseev, N B; Levitskiĭ, D I

    2008-01-01

    We applied different methods to analyze the effects of the recombinant wild-type small heat shock protein with an apparent molecular mass of 27 kD (Hsp27-wt) and its S15,78,82D mutant (Hsp27-3D), which mimics the naturally occurring phosphorylation of this protein, on the thermal denaturation and aggregation of F-actin. It has been shown that, at the weight ratio of Hsp27/actin equal to 1/4, both Hsp27-wt and Hsp27-3D do not affect the thermal unfolding of F-actin but effectively prevent the aggregation of F-actin by forming soluble complexes with denatured actin. The formation of these complexes occurs upon heating and accompanies the F-actin thermal denaturation. It is known that Hsp27-wt forms high-molecular-mass oligomers, whereas Hsp27-3D forms small dimers or tetramers. However, the complexes formed by Hsp27-wt and Hsp27-3D with denatured actin did not differ in their size, as measured by dynamic light scattering, and demonstrated the same hydrodynamic radius of 17-18 nm. On the other hand, the sedimentation coefficients of these complexes were distributed within the range 10-45 S in the case of Hsp27-3D and 18-60 S in the case of Hsp27-wt. Thus, the ability of Hsp27 to form soluble complexes with denatured actin does not significantly depend on the initial oligomeric state of Hsp27.

  19. Interaction of the sea breeze with a river breeze in an area of complex coastal heating

    NASA Technical Reports Server (NTRS)

    Zhong, Shiyuan; Takle, Eugene S.; Leone, John M., Jr.

    1991-01-01

    The interaction of the sea-breeze circulation with a river-breeze circulation in an area of complex coastal heating (east coast of Florida) was studied using a 3D finite-element mesoscale model. The model simulations are compared with temperature and wind fields observed on a typical fall day during the Kennedy Space Center Atmospheric Boundary Layer Experiment. The results from numerical experiments designed to isolate the effect of the river breeze indicate that the convergence in the sea-breeze front is suppressed when it passes over the cooler surface of the rivers.

  20. Small heat shock protein Hsp27 prevents heat-induced aggregation of F-actin by forming soluble complexes with denatured actin.

    PubMed

    Pivovarova, Anastasia V; Chebotareva, Natalia A; Chernik, Ivan S; Gusev, Nikolai B; Levitsky, Dmitrii I

    2007-11-01

    Previously, we have shown that the small heat shock protein with apparent molecular mass 27 kDa (Hsp27) does not affect the thermal unfolding of F-actin, but effectively prevents aggregation of thermally denatured F-actin [Pivovarova AV, Mikhailova VV, Chernik IS, Chebotareva NA, Levitsky DI & Gusev NB (2005) Biochem Biophys Res Commun331, 1548-1553], and supposed that Hsp27 prevents heat-induced aggregation of F-actin by forming soluble complexes with denatured actin. In the present work, we applied dynamic light scattering, analytical ultracentrifugation and size exclusion chromatography to examine the properties of complexes formed by denatured actin with a recombinant human Hsp27 mutant (Hsp27-3D) mimicking the naturally occurring phosphorylation of this protein at Ser15, Ser78, and Ser82. Our results show that formation of these complexes occurs upon heating and accompanies the F-actin thermal denaturation. All the methods show that the size of actin-Hsp27-3D complexes decreases with increasing Hsp27-3D concentration in the incubation mixture and that saturation occurs at approximately equimolar concentrations of Hsp27-3D and actin. Under these conditions, the complexes exhibit a hydrodynamic radius of approximately 16 nm, a sedimentation coefficient of 17-20 S, and a molecular mass of about 2 MDa. It is supposed that Hsp27-3D binds to denatured actin monomers or short oligomers dissociated from actin filaments upon heating and protects them from aggregation by forming relatively small and highly soluble complexes. This mechanism might explain how small heat shock proteins prevent aggregation of denatured actin and by this means protect the cytoskeleton and the whole cell from damage caused by accumulation of large insoluble aggregates under heat shock conditions.

  1. Effect of CMC Molecular Weight on Acid-Induced Gelation of Heated WPI-CMC Soluble Complex.

    PubMed

    Huan, Yan; Zhang, Sha; Vardhanabhuti, Bongkosh

    2016-02-01

    Acid-induced gelation properties of heated whey protein isolate (WPI) and carboxymethylcellulose (CMC) soluble complex were investigated as a function of CMC molecular weight (270, 680, and 750 kDa) and concentrations (0% to 0.125%). Heated WPI-CMC soluble complex with 6% protein was made by heating biopolymers together at pH 7.0 and 85 °C for 30 min and diluted to 5% protein before acid-induced gelation. Acid-induced gel formed from heated WPI-CMC complexes exhibited increased hardness and decreased water holding capacity with increasing CMC concentrations but gel strength decreased at higher CMC content. The highest gel strength was observed with CMC 750 k at 0.05%. Gels with low CMC concentration showed homogenous microstructure which was independent of CMC molecular weight, while increasing CMC concentration led to microphase separation with higher CMC molecular weight showing more extensive phase separation. When heated WPI-CMC complexes were prepared at 9% protein the acid gels showed improved gel hardness and water holding capacity, which was supported by the more interconnected protein network with less porosity when compared to complexes heated at 6% protein. It is concluded that protein concentration and biopolymer ratio during complex formation are the major factors affecting gel properties while the effect of CMC molecular weight was less significant. © 2016 Institute of Food Technologists®

  2. Cooling systems and hybrid A/C systems using an electromagnetic radiation-absorbing complex

    DOEpatents

    Halas, Nancy J.; Nordlander, Peter; Neumann, Oara

    2015-05-19

    A method for powering a cooling unit. The method including applying electromagnetic (EM) radiation to a complex, where the complex absorbs the EM radiation to generate heat, transforming, using the heat generated by the complex, a fluid to vapor, and sending the vapor from the vessel to a turbine coupled to a generator by a shaft, where the vapor causes the turbine to rotate, which turns the shaft and causes the generator to generate the electric power, wherein the electric powers supplements the power needed to power the cooling unit

  3. Filter vapor trap

    DOEpatents

    Guon, Jerold

    1976-04-13

    A sintered filter trap is adapted for insertion in a gas stream of sodium vapor to condense and deposit sodium thereon. The filter is heated and operated above the melting temperature of sodium, resulting in a more efficient means to remove sodium particulates from the effluent inert gas emanating from the surface of a liquid sodium pool. Preferably the filter leaves are precoated with a natrophobic coating such as tetracosane.

  4. A Stereospecific Vapor Detector.

    DTIC Science & Technology

    1984-03-26

    to be done next is to determine the state of aggregation of the iron in the cesium iodide matrix. Is it present as single atoms, small clusters...its polarity and tendency to aggregate , on the properties of the host matrix material such as its heat of vaporization, and on the temperature and...has been filed. COry \\NSf’! CTED (ii) The next question had to do with the state of aggregation of the ’_ guest molecules: if these molecules are not

  5. Melting transition in a two-dimensional complex plasma heated by driven acoustic instability

    SciTech Connect

    Sheridan, T. E.

    2008-10-15

    The melting transition in a two-dimensional complex (dusty) plasma is studied experimentally. A system consisting of {approx_equal}3900 microspheres is heated by amplitude modulating the rf discharge power with a square wave at the vertical resonance frequency. The vertical motion couples to an in-plane dust-acoustic instability at one-half the modulation frequency, thereby increasing the complex plasma's effective temperature. The 'thermodynamic' phase of the system is characterized for increasing levels of amplitude modulation at constant neutral pressure (35 mTorr Ar) and average rf power using the Lindemann ratio, defect density, bond-orientational correlation function, and pair correlation function. A melting transition showing evidence for an intermediate hexatic phase is observed.

  6. Characterization of the Sublimation and Vapor Pressure of 2-(2-Nitrovinyl) Furan (G-0) Using Thermogravimetric Analysis: Effects of Complexation with Cyclodextrins.

    PubMed

    Ruz, Vivian; González, Mirtha Mayra; Winant, Danny; Rodríguez, Zenaida; Van den Mooter, Guy

    2015-08-19

    In the present work, the sublimation of crystalline solid 2-(2-nitrovinyl) furan (G-0) in the temperature range of 35 to 60 °C (below the melting point of the drug) was studied using thermogravimetric analysis (TGA). The sublimated product was characterized using Fourier-transformed-infrared spectroscopy (FT-IR) and thin layer chromatography (TLC). The sublimation rate at each temperature was obtained using the slope of the linear regression model and followed apparent zero-order kinetics. The sublimation enthalpy from 35 to 60 °C was obtained from the Eyring equation. The Gückel method was used to estimate the sublimation rate and vapor pressure at 25 °C. Physical mixtures, kneaded and freeze-dried complexes were prepared with 2-hydroxypropyl-β-cyclodextrin (HP-β-CD) and sulfobutyl ether-β-cyclodextrin (SBE-β-CD) and analyzed using isothermal TGA at 50 °C. The complexation contributed to reducing the sublimation process. The best results were achieved using freeze-dried complexes with both cyclodextrins.

  7. A Lithium Vapor Box similarity experiment employing water vapor

    NASA Astrophysics Data System (ADS)

    Schwartz, Ja; Jagoe, C.; Goldston, Rj; Jaworski, Ma

    2016-10-01

    Handling high power loads and heat flux in the divertor is a major challenge for fusion power plants. A detached plasma will likely be required. However, hydrogenic and impurity puffing experiments show that detached operation leads easily to X-point MARFEs, impure plasmas, degradation in confinement, and lower helium pressure at the exhaust. The concept of the Lithium Vapor Box Divertor is to use local evaporation and strong differential pumping through condensation to localize the gas-phase material that absorbs the plasma heat flux, and so avoid those difficulties. In order to design such a box first the vapor without plasma must be simulated. The density of vapor required can be estimated using the SOL power, major radius, poloidal box length, and cooling energy per lithium atom. For an NSTX-U-sized machine, the Knudsen number Kn spans 0.01 to 1, the transitional flow regime. This regime cannot handled by fluid codes or collisionless Monte Carlo codes, but can be handled by Direct Simulation Monte Carlo (DSMC) codes. To validate a DSMC model, we plan to build a vapor box test stand employing more-convenient water vapor instead of lithium vapor as the working fluid. Transport of vapor between the chambers at -50C will be measured and compared to the model. This work supported by DOE Contract No. DE-AC02-09CH11466.

  8. Synthesis and modeling of uniform complex metal oxides by close-proximity atmospheric pressure chemical vapor deposition.

    PubMed

    Hoye, Robert L Z; Muñoz-Rojas, David; Musselman, Kevin P; Vaynzof, Yana; MacManus-Driscoll, Judith L

    2015-05-27

    A close-proximity atmospheric pressure chemical vapor deposition (AP-CVD) reactor is developed for synthesizing high quality multicomponent metal oxides for electronics. This combines the advantages of a mechanically controllable substrate-manifold spacing and vertical gas flows. As a result, our AP-CVD reactor can rapidly grow uniform crystalline films on a variety of substrate types at low temperatures without requiring plasma enhancements or low pressures. To demonstrate this, we take the zinc magnesium oxide (Zn(1-x)Mg(x)O) system as an example. By introducing the precursor gases vertically and uniformly to the substrate across the gas manifold, we show that films can be produced with only 3% variation in thickness over a 375 mm(2) deposition area. These thicknesses are significantly more uniform than for films from previous AP-CVD reactors. Our films are also compact, pinhole-free, and have a thickness that is linearly controllable by the number of oscillations of the substrate beneath the gas manifold. Using photoluminescence and X-ray diffraction measurements, we show that for Mg contents below 46 at. %, single phase Zn(1-x)Mg(x)O was produced. To further optimize the growth conditions, we developed a model relating the composition of a ternary oxide with the bubbling rates through the metal precursors. We fitted this model to the X-ray photoelectron spectroscopy measured compositions with an error of Δx = 0.0005. This model showed that the incorporation of Mg into ZnO can be maximized by using the maximum bubbling rate through the Mg precursor for each bubbling rate ratio. When applied to poly(3-hexylthiophene-2,5-diyl) hybrid solar cells, our films yielded an open-circuit voltage increase of over 100% by controlling the Mg content. Such films were deposited in short times (under 2 min over 4 cm(2)).

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

    SciTech Connect

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

    2006-05-05

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

  10. A new method for predicting the solar heat gain of complex fenestration systems

    SciTech Connect

    Klems, J.H.; Warner, J.L.; Kelley, G.O.

    1995-03-01

    A new method of predicting the solar heat gain through complex fenestration systems involving nonspecular layers such as shades or blinds has been examined in a project jointly sponsored by ASHRAE and DOE. In this method, a scanning radiometer is used to measure the bidirectional radiative transmittance and reflectance of each layer of a fenestration system. The properties of systems containing these layers are then built up computationally from the measured layer properties using a transmission/multiple-reflection calculation. The calculation produces the total directional-hemispherical transmittance of the fenestration system and the layer-by-layer absorbances. These properties are in turn combined with layer-specific measurements of the inward-flowing fractions of absorbed solar energy to produce the overall solar heat gain coefficient. The method has been applied to one of the most optically complex systems in common use, a venetian blind in combination with multiple glazings. A comparison between the scanner-based calculation method and direct system calorimetric measurements made on the LBL MoWiTT facility showed good agreement, and is a significant validation of the method accuracy and feasibility.

  11. Determination of thiolic compounds as mercury complexes by cold vapor atomic absorption spectrometry and its application to wines.

    PubMed

    Bramanti, Emilia; Cavallaro, Rosa; Onor, Massimo; Zamboni, Roberto; D'Ulivo, Alessandro

    2008-01-15

    We report on the application of a commercially available mercury analyzer, which is based on vapour generation of Hg(0) by NaBH(4) reduction and atomic absorption detection, to the quantification and characterization of -SH groups and its application to wine samples. The behaviour of Hg(II) and thiol-Hg(II) (RS-Hg) complexes at nanomolar level (RS=l-cysteine, dl-penicillamine, N-acetyl penicillamine, glutathione, cysteinylglycine, homocysteine) has been studied following their reduction with alkaline NaBH(4) to give Hg(0). In the absence of thiol-Hg(II) is quantitatively converted to Hg(0) by stoichiometric amount of NaBH(4) (reaction ratio 1/4mole NaBH(4)/mole Hg), while the complete reduction of Hg(II)-thiol complexes to Hg(0) requires molar excess of NaBH(4) up to six orders of magnitude, depending on the type of complex and on the pK(a) of the thiolic group. Under an appropriate excess of reductant, Hg(II) and its thiol complexes are not distinguishable giving the same response. These properties allow the discrimination of Hg(II) from Hg(II)-thiol complexes without any preliminary separation and the quantification of thiol groups. Instrumental detection limits are as low as 2.5pg, permitting sample dilution, therefore, minimizing the risk of possible interferences occurring with complex real matrices. The method has been applied to quantification of thiol groups in wine samples. Comparison with results obtained by HPLC coupled to atomic fluorescence detection confirmed the promising potentialities of the method.

  12. Evidence for Multiple Mediator Complexes in Yeast Independently Recruited by Activated Heat Shock Factor

    PubMed Central

    Anandhakumar, Jayamani; Moustafa, Yara W.; Chowdhary, Surabhi; Kainth, Amoldeep S.

    2016-01-01

    Mediator is an evolutionarily conserved coactivator complex essential for RNA polymerase II transcription. Although it has been generally assumed that in Saccharomyces cerevisiae, Mediator is a stable trimodular complex, its structural state in vivo remains unclear. Using the “anchor away” (AA) technique to conditionally deplete select subunits within Mediator and its reversibly associated Cdk8 kinase module (CKM), we provide evidence that Mediator's tail module is highly dynamic and that a subcomplex consisting of Med2, Med3, and Med15 can be independently recruited to the regulatory regions of heat shock factor 1 (Hsf1)-activated genes. Fluorescence microscopy of a scaffold subunit (Med14)-anchored strain confirmed parallel cytoplasmic sequestration of core subunits located outside the tail triad. In addition, and contrary to current models, we provide evidence that Hsf1 can recruit the CKM independently of core Mediator and that core Mediator has a role in regulating postinitiation events. Collectively, our results suggest that yeast Mediator is not monolithic but potentially has a dynamic complexity heretofore unappreciated. Multiple species, including CKM-Mediator, the 21-subunit core complex, the Med2-Med3-Med15 tail triad, and the four-subunit CKM, can be independently recruited by activated Hsf1 to its target genes in AA strains. PMID:27185874

  13. Collapse of large vapor bubbles

    NASA Technical Reports Server (NTRS)

    Tegart, J.; Dominick, S.

    1982-01-01

    The refilling of propellant tanks while in a low-gravity environment requires that entrapped vapor bubbles be collapsed by increasing the system pressure. Tests were performed to verify the mechanism of collapse for these large vapor bubbles with the thermodynamic conditions, geometry, and boundary conditions being those applicable to propellant storage systems. For these conditions it was found that conduction heat transfer determined the collapse rate, with the specific bubble geometry having a significant influence.

  14. Condensation of vapor bubble in subcooled pool

    NASA Astrophysics Data System (ADS)

    Horiuchi, K.; Koiwa, Y.; Kaneko, T.; Ueno, I.

    2017-02-01

    We focus on condensation process of vapor bubble exposed to a pooled liquid of subcooled conditions. Two different geometries are employed in the present research; one is the evaporation on the heated surface, that is, subcooled pool boiling, and the other the injection of vapor into the subcooled pool. The test fluid is water, and all series of the experiments are conducted under the atmospheric pressure condition. The degree of subcooling is ranged from 10 to 40 K. Through the boiling experiment, unique phenomenon known as microbubble emission boiling (MEB) is introduced; this phenomenon realizes heat flux about 10 times higher than the critical heat flux. Condensation of the vapor bubble is the key phenomenon to supply ambient cold liquid to the heated surface. In order to understand the condensing process in the MEB, we prepare vapor in the vapor generator instead of the evaporation on the heated surface, and inject the vapor to expose the vapor bubble to the subcooled liquid. Special attention is paid to the dynamics of the vapor bubble detected by the high-speed video camera, and on the enhancement of the heat transfer due to the variation of interface area driven by the condensation.

  15. Precision ozone vapor pressure measurements

    NASA Technical Reports Server (NTRS)

    Hanson, D.; Mauersberger, K.

    1985-01-01

    The vapor pressure above liquid ozone has been measured with a high accuracy over a temperature range of 85 to 95 K. At the boiling point of liquid argon (87.3 K) an ozone vapor pressure of 0.0403 Torr was obtained with an accuracy of + or - 0.7 percent. A least square fit of the data provided the Clausius-Clapeyron equation for liquid ozone; a latent heat of 82.7 cal/g was calculated. High-precision vapor pressure data are expected to aid research in atmospheric ozone measurements and in many laboratory ozone studies such as measurements of cross sections and reaction rates.

  16. Heating systems for heating subsurface formations

    DOEpatents

    Nguyen, Scott Vinh [Houston, TX; Vinegar, Harold J [Bellaire, TX

    2011-04-26

    Methods and systems for heating a subsurface formation are described herein. A heating system for a subsurface formation includes a sealed conduit positioned in an opening in the formation and a heat source. The sealed conduit includes a heat transfer fluid. The heat source provides heat to a portion of the sealed conduit to change phase of the heat transfer fluid from a liquid to a vapor. The vapor in the sealed conduit rises in the sealed conduit, condenses to transfer heat to the formation and returns to the conduit portion as a liquid.

  17. Vapor fragrancer

    NASA Astrophysics Data System (ADS)

    Sang, Q. Tran; Bryant, Timothy D.

    1987-05-01

    This invention relates to a vapor fragrancer for continuously, uniformly, and economically odorizing or deodorizing an environment. Homes, offices, automobiles, and space stations require either odorizing or deodorizing of the atmosphere to create pleasant conditions for work or leisure. A vapor fragrancer is provided to accomplish these goals. A supplier continuously supplies a predetermined amount of desired liquid fragrance from a container to a retaining material, which is positioned in the circulation path of the atmosphere. The supplier is either a low powered pump or a gravity dispenser. The atmosphere flowing in a circulation path passes over the retaining material containing the liquid fragrance and lifts a fragrant vapor from the retaining material. The atmosphere is thereby continuously and uniformly fragranced.

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

    PubMed

    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.

  19. Heat-induced reorganization of the structure of photosystem II membranes: role of oxygen evolving complex.

    PubMed

    Busheva, Mira; Tzonova, Iren; Stoitchkova, Katerina; Andreeva, Atanaska

    2012-12-05

    The sensitivity of the green plants' photosystem II (PSII) to high temperatures is investigated in PSII enriched membranes and in membranes, from which the oxygen evolving complex is removed. Using steady-state 77 K fluorescence and resonance Raman spectroscopy we analyze the interdependency between the temperature-driven changes in structure and energy distribution in the PSII supercomplex. The results show that the heat treatment induces different reduction of the 77 K fluorescence emission in both types of investigated membranes: (i) an additional considerable decrease of the overall fluorescence emission in Tris-washed membranes as compared to the native membranes; (ii) a transition point at 42°C(,) observed only in native membranes; (iii) a sharp reduction of the PSII core fluorescence in Tris-washed membranes at temperatures higher than 50°C; (iv) a 3 nm red-shift of F700 band's maximum in Tris-washed membranes already at 20°C and its further shift by 1 nm at temperature increase. Both treatments intensified their action by increasing the aggregation and dissociation of the peripheral light harvesting complexes. The oxygen-evolving complex, in addition to its main function to produce O(2), increases the thermal stability of PSII core by strengthening the connection between the core and the peripheral antenna proteins and by keeping their structural integrity.

  20. Heat-Pipe Array for Large-Area Cooling

    NASA Technical Reports Server (NTRS)

    Edelstein, F.; Brown, R. F.

    1986-01-01

    High rates of heat transfer anticipated. Prototype evaporative cold plate gathers waste heat from equipment mounted on it. Plate made by welding together flanges of several sections of heat pipe. Since plate separates liquid and vapor phases at inlet and outlet ports, eliminates complexities and uncertainties of two-phase flow in zero gravity. On earth, inlet valve enables plate to operate at relatively-large height differences with other plates in same system.

  1. The JCMT Gould Belt Survey: evidence for radiative heating and contamination in the W40 complex

    NASA Astrophysics Data System (ADS)

    Rumble, D.; Hatchell, J.; Pattle, K.; Kirk, H.; Wilson, T.; Buckle, J.; Berry, D. S.; Broekhoven-Fiene, H.; Currie, M. J.; Fich, M.; Jenness, T.; Johnstone, D.; Mottram, J. C.; Nutter, D.; Pineda, J. E.; Quinn, C.; Salji, C.; Tisi, S.; Walker-Smith, S.; di Francesco, J.; Hogerheijde, M. R.; Ward-Thompson, D.; Bastien, P.; Bresnahan, D.; Butner, H.; Chen, M.; Chrysostomou, A.; Coude, S.; Davis, C. J.; Drabek-Maunder, E.; Duarte-Cabral, A.; Fiege, J.; Friberg, P.; Friesen, R.; Fuller, G. A.; Graves, S.; Greaves, J.; Gregson, J.; Holland, W.; Joncas, G.; Kirk, J. M.; Knee, L. B. G.; Mairs, S.; Marsh, K.; Matthews, B. C.; Moriarty-Schieven, G.; Mowat, C.; Rawlings, J.; Richer, J.; Robertson, D.; Rosolowsky, E.; Sadavoy, S.; Thomas, H.; Tothill, N.; Viti, S.; White, G. J.; Wouterloot, J.; Yates, J.; Zhu, M.

    2016-08-01

    We present SCUBA-2 450 μm and 850 μm observations of the W40 complex in the Serpens-Aquila region as part of the James Clerk Maxwell Telescope (JCMT) Gould Belt Survey (GBS) of nearby star-forming regions. We investigate radiative heating by constructing temperature maps from the ratio of SCUBA-2 fluxes using a fixed dust opacity spectral index, β = 1.8, and a beam convolution kernel to achieve a common 14.8 arcsec resolution. We identify 82 clumps ranging between 10 and 36 K with a mean temperature of 20 ± 3 K. Clump temperature is strongly correlated with proximity to the external OB association and there is no evidence that the embedded protostars significantly heat the dust. We identify 31 clumps that have cores with densities greater than 105cm-3. 13 of these cores contain embedded Class 0/I protostars. Many cores are associated with bright-rimmed clouds seen in Herschel 70 μm images. From JCMT HARP observations of the 12CO 3-2 line, we find contamination of the 850 μm band of up to 20 per cent. We investigate the free-free contribution to SCUBA-2 bands from large-scale and ultracompact H II regions using archival VLA data and find the contribution is limited to individual stars, accounting for 9 per cent of flux per beam at 450 μm or 12 per cent at 850 μm in these cases. We conclude that radiative heating has potentially influenced the formation of stars in the Dust Arc sub-region, favouring Jeans stable clouds in the warm east and fragmentation in the cool west.

  2. Vapor Detector

    NASA Technical Reports Server (NTRS)

    Waddell, H. M.; Garrard, G. C.; Houston, D. W.

    1982-01-01

    Detector eliminates need for removing covers to take samples. Detector is canister consisting of screw-in base and clear plastic tube that contains two colors of silica gel. Monoethylhydrazine and nitrogen tetroxide vapors are visually monitored with canister containing color-changing gels.

  3. Heat-induced formation of myosin oligomer-soluble filament complex in high-salt solution.

    PubMed

    Shimada, Masato; Takai, Eisuke; Ejima, Daisuke; Arakawa, Tsutomu; Shiraki, Kentaro

    2015-02-01

    Heat-induced aggregation of myosin into an elastic gel plays an important role in the water-holding capacity and texture of meat products. Here, we investigated thermal aggregation of porcine myosin in high-salt solution over a wide temperature range by dynamic light scattering experiments. The myosin samples were readily dissolved in 1.0 M NaCl at 25 °C followed by dilution into various salt concentrations. The diluted solutions consistently contained both myosin monomers and soluble filaments. The filament size decreased with increasing salt concentration and temperature. High temperatures above Tm led to at least partial dissociation of soluble filaments and thermal unfolding, resulting in the formation of soluble oligomers and binding to the persistently present soluble filaments. Such a complex formation between the oligomers and filaments has never been observed. Our results provide new insight into the heat-induced myosin gelation in high-salt solution. Copyright © 2014 Elsevier B.V. All rights reserved.

  4. Heat transfer system

    DOEpatents

    Not Available

    1980-03-07

    A heat transfer system for a nuclear reactor is described. Heat transfer is accomplished within a sealed vapor chamber which is substantially evacuated prior to use. A heat transfer medium, which is liquid at the design operating temperatures, transfers heat from tubes interposed in the reactor primary loop to spaced tubes connected to a steam line for power generation purposes. Heat transfer is accomplished by a two-phase liquid-vapor-liquid process as used in heat pipes. Condensible gases are removed from the vapor chamber through a vertical extension in open communication with the chamber interior.

  5. Heat transfer system

    DOEpatents

    McGuire, Joseph C.

    1982-01-01

    A heat transfer system for a nuclear reactor. Heat transfer is accomplished within a sealed vapor chamber which is substantially evacuated prior to use. A heat transfer medium, which is liquid at the design operating temperatures, transfers heat from tubes interposed in the reactor primary loop to spaced tubes connected to a steam line for power generation purposes. Heat transfer is accomplished by a two-phase liquid-vapor-liquid process as used in heat pipes. Condensible gases are removed from the vapor chamber through a vertical extension in open communication with the chamber interior.

  6. Mathematical modeling of heat transfer processes of coal waste combustion in a chamber of automated energy generating complex

    NASA Astrophysics Data System (ADS)

    Mochalov, Sergey P.; Kalashnikov, Sergey N.; Mochalov, Pavel S.; Song, Guolin; Tang, Guoyi

    2013-04-01

    The automated energy generating complex allows obtaining heat energy from waste coal-water slurry fuel (WCF) that is a mixture of fine coal particles from coal enrichment wastes with water. The mixture is blown into the swirl chamber under the pressure through the special sprayers. The received heat energy is used in different ways. One of the important issues is to estimate the heat losses through the walls of this chamber. In this paper we solved the boundary problem of mathematical physics to estimate the temperature fields in the walls of the swirl chamber. The obtained solution allows us to estimate the heat losses through the walls of the swirl chamber. The task of the mathematical physics has been solved by a numerical finite-difference method. The method for solving this problem can be used in the calculation of temperature fields and evaluation of heat losses in other thermal power units.

  7. Removal of the process-induced fluorine associated to chemical vapor deposition of tungsten onto a polycrystalline silicon gate structure by heat treatment in a hydrogen-containing atmosphere

    NASA Astrophysics Data System (ADS)

    Eriksson, Th.; Carlsson, J.-O.; Mohadjeri, B.; Östling, M.; d'Heurle, F. M.; Petersson, C. S.; Keinonen, J.

    1990-09-01

    Tungsten was deposited from a gas mixture of hydrogen and tungsten hexafluoride onto a polycrystalline silicon gate structure in a chemical vapor deposition system. During the deposition process fluorine was also deposited as an undesired impurity. In order to remove the fluorine, heat treatments in the temperature range 550-1050 °C were performed in a hydrogen atmosphere. By this treatment it is possible to form volatile hydrofluoric acid and hence remove fluorine from the structure. Nuclear-resonance-broadening technique and secondary ion mass spectrometry were used for the analysis of fluorine. Fluorine was detected in all the samples except for the sample heat treated at 1050 °C. Moreover, etching of the polycrystalline silicon was observed. The gettering of fluorine, the etching of silicon and the observed formation of tungsten disilicide at 650 °C are discussed with respect to conceivable mechanisms. A thermodynamic study supporting the interpretations is also included.

  8. The application of complex network time series analysis in turbulent heated jets

    SciTech Connect

    Charakopoulos, A. K.; Karakasidis, T. E. Liakopoulos, A.; Papanicolaou, P. N.

    2014-06-15

    In the present study, we applied the methodology of the complex network-based time series analysis to experimental temperature time series from a vertical turbulent heated jet. More specifically, we approach the hydrodynamic problem of discriminating time series corresponding to various regions relative to the jet axis, i.e., time series corresponding to regions that are close to the jet axis from time series originating at regions with a different dynamical regime based on the constructed network properties. Applying the transformation phase space method (k nearest neighbors) and also the visibility algorithm, we transformed time series into networks and evaluated the topological properties of the networks such as degree distribution, average path length, diameter, modularity, and clustering coefficient. The results show that the complex network approach allows distinguishing, identifying, and exploring in detail various dynamical regions of the jet flow, and associate it to the corresponding physical behavior. In addition, in order to reject the hypothesis that the studied networks originate from a stochastic process, we generated random network and we compared their statistical properties with that originating from the experimental data. As far as the efficiency of the two methods for network construction is concerned, we conclude that both methodologies lead to network properties that present almost the same qualitative behavior and allow us to reveal the underlying system dynamics.

  9. The application of complex network time series analysis in turbulent heated jets.

    PubMed

    Charakopoulos, A Κ; Karakasidis, T E; Papanicolaou, P N; Liakopoulos, A

    2014-06-01

    In the present study, we applied the methodology of the complex network-based time series analysis to experimental temperature time series from a vertical turbulent heated jet. More specifically, we approach the hydrodynamic problem of discriminating time series corresponding to various regions relative to the jet axis, i.e., time series corresponding to regions that are close to the jet axis from time series originating at regions with a different dynamical regime based on the constructed network properties. Applying the transformation phase space method (k nearest neighbors) and also the visibility algorithm, we transformed time series into networks and evaluated the topological properties of the networks such as degree distribution, average path length, diameter, modularity, and clustering coefficient. The results show that the complex network approach allows distinguishing, identifying, and exploring in detail various dynamical regions of the jet flow, and associate it to the corresponding physical behavior. In addition, in order to reject the hypothesis that the studied networks originate from a stochastic process, we generated random network and we compared their statistical properties with that originating from the experimental data. As far as the efficiency of the two methods for network construction is concerned, we conclude that both methodologies lead to network properties that present almost the same qualitative behavior and allow us to reveal the underlying system dynamics.

  10. Assessment of the CCSD and CCSD(T) Coupled-Cluster Methods in Calculating Heats of Formation for Zn Complexes

    PubMed Central

    Weaver, Michael N.; Yang, Yue

    2010-01-01

    Heats of formation were calculated using coupled-cluster methods for a series of zinc complexes. The calculated values were evaluated against previously conducted computational studies using density functional methods as well as experimental values. Heats of formation for nine neutral ZnXn complexes [X = -Zn, -H, -O, -F2, -S, -Cl, -Cl2, -CH3, (-CH3)2] were determined at the CCSD and CCSD(T) levels using the 6–31G** and TZVP basis sets, as well as the LANL2DZ-6–31G** (LACVP**) and LANL2DZ-TZVP hybrid basis sets. The CCSD(T)/6–31G** level of theory was found to predict the heat of formation for the non-alkyl Zn complexes most accurately. The alkyl Zn species were problematic in that none of the methods that were tested accurately predicted the heat of formation for these complexes. For the seven non-alkyl species, the CCSD(T)/6–31G** level of theory was shown to predict the most accurate heat of formation values. In instances where experimental geometric parameters were available, these were most accurately predicted by the CCSD/6–31G** level of theory; going to CCSD(T) did not improve agreement with the experimental values. PMID:19691272

  11. Heat Shock Protein 90 Ensures Efficient Mumps Virus Replication by Assisting with Viral Polymerase Complex Formation.

    PubMed

    Katoh, Hiroshi; Kubota, Toru; Nakatsu, Yuichiro; Tahara, Maino; Kidokoro, Minoru; Takeda, Makoto

    2017-03-15

    Paramyxoviral RNAs are synthesized by a viral RNA-dependent RNA polymerase (RdRp) consisting of the large (L) protein and its cofactor phosphoprotein (P protein). The L protein is a multifunctional protein that catalyzes RNA synthesis, mRNA capping, and mRNA polyadenylation. Growing evidence shows that the stability of several paramyxovirus L proteins is regulated by heat shock protein 90 (Hsp90). In this study, we demonstrated that Hsp90 activity was important for mumps virus (MuV) replication. The Hsp90 activity was required for L-protein stability and activity because an Hsp90-specific inhibitor, 17-allylamino-17-demethoxygeldanamycin (17-AAG), destabilized the MuV L protein and suppressed viral RNA synthesis. However, once the L protein formed a mature polymerase complex with the P protein, Hsp90 activity was no longer required for the stability and activity of the L protein. When the Hsp90 activity was inhibited, the MuV L protein was degraded through the CHIP (C terminus of Hsp70-interacting protein)-mediated proteasomal pathway. High concentrations of 17-AAG showed strong cytotoxicity to certain cell types, but combined use of an Hsp70 inhibitor, VER155008, potentiated degradation of the L protein, allowing a sufficient reduction of 17-AAG concentration to block MuV replication with minimum cytotoxicity. Regulation of the L protein by Hsp90 and Hsp70 chaperones was also demonstrated for another paramyxovirus, the measles virus. Collectively, our data show that the Hsp90/Hsp70 chaperone machinery assists in the maturation of the paramyxovirus L protein and thereby in the formation of a mature RdRp complex and efficient viral replication.IMPORTANCE Heat shock protein 90 (Hsp90) is nearly universally required for viral protein homeostasis. Here, we report that Hsp90 activity is required for efficient propagation of mumps virus (MuV). Hsp90 functions in the maintenance of the catalytic subunit of viral polymerase, the large (L) protein, prior to formation of a

  12. Separation of an associated 90K heat shock protein from the glucocorticoid receptor complex

    SciTech Connect

    Miller-Diener, A.; Kirsch, T.; Grove, B.; Robertson, N.; Litwack, G.

    1986-05-01

    A 90K heat shock protein(HSP), observed to copurify with the glucocorticoid receptor(GR), can be separated from the complex by 2 methods, allowing investigation of the role of HSP on kinase activity that was previously reported to be inherent to purified activated GR. Na/sub 2/MoO/sub 4/ stabilized unactivated rat hepatic GR complexes have been purified to >10,000-fold using a purification scheme that involves batchwise treatment of cytosol with phosphocellulose/DNAcellulose, elution from an affinity resin, gel filtration and ion exchange chromatography. Samples were subjected to 10-20% gradient SDS-PAGE. Proteins were transferred to nitrocellulose and blotted against monoclonal antibodies to GR(3A6), HSP or nonspecific IgM/G. Immunoblots indicated that HSP was separated from unactivated GR complexes at the affinity step prior to elution of GR with active steroid. GR eluted from the resin with /sup 3/H Triamcinolone acetonide or /sup 3/H Dexamethasone mesylate had an apparent M/sub r/ = 94-96,000 for the steroid binding subunit and is recognized by 3A6. Purification of GR minus the affinity step resulted in copurification of HSP throughout the procedure. However, after Sephadex G75 filtration and subsequent incubation at 25/sup 0/C, 30 min., HSP was separated from activated (DNA binding) GR on DEAE cellulose-52. HSP did not enhance or inhibit /sup 32/P incorporation of the 94K steroid binding subunit nor did it affect phosphorylation of histones by GR.

  13. MEMS Lubrication by In-Situ Tribochemical Reactions From the Vapor Phase.

    SciTech Connect

    Dugger, Michael Thomas; Asay, David B.; Kim, Seong H.

    2008-01-01

    Vapor Phase Lubrication (VPL) of silicon surfaces with pentanol has been demonstrated. Two potential show stoppers with respect to application of this approach to real MEMS devices have been investigated. Water vapor was found to reduce the effectiveness of VPL with alcohol for a given alcohol concentration, but the basic reaction mechanism observed in water-free environments is still active, and devices operated much longer in mixed alcohol and water vapor environments than with chemisorbed monolayer lubricants alone. Complex MEMS gear trains were successfully lubricated with alcohol vapors, resulting in a factor of 104 improvement in operating life without failure. Complex devices could be made to fail if operated at much higher frequencies than previously used, and there is some evidence that the observed failure is due to accumulation of reaction products at deeply buried interfaces. However, if hypothetical reaction mechanisms involving heated surfaces are valid, then the failures observed at high frequency may not be relevant to operation at normal frequencies. Therefore, this work demonstrates that VPL is a viable approach for complex MEMS devices in conventional packages. Further study of the VPL reaction mechanisms are recommended so that the vapor composition may be optimized for low friction and for different substrate materials with potential application to conventionally fabricated, metal alloy parts in weapons systems. Reaction kinetics should be studied to define effective lubrication regimes as a function of the partial pressure of the vapor phase constituent, interfacial shear rate, substrate composition, and temperature.

  14. Improving the emulsifying properties of β-lactoglobulin-wild almond gum (Amygdalus scoparia Spach) exudate complexes by heat.

    PubMed

    Golkar, Abdolkhalegh; Nasirpour, Ali; Keramat, Javad

    2017-01-01

    The present study aims to investigate the advantageous effects of wet heating, BLG (β-lactoglobulin)/Ang (Angum gum) ratio, and pH (normal pH of mixed BLG and Ang solutions, pHc > pH > pHΦ1 ) on the emulsifying properties of wet-heated β-lactoglobulin-wild almond gum exudate (Amygdalus scoparia Spach) mixture over those of electrostatic counterparts. Covalent linkage of BLG-Ang conjugates was confirmed by SDS-PAGE and FTIR analysis. Emulsion activity (EA), emulsion stability (ES), and droplet size characteristics of emulsions were significantly (P < 0.05 and P < 0.01) affected by electrostatic/wet-heating, biopolymer ratio, pH, and their interactions. The electrostatic complexes with pHc > pH > pHΦ1 exhibited higher EA and ES values for all the biopolymer ratios investigated than their electrostatic counterparts with pH after mixing. However, these values for the wet-heated samples at pH after mixing were found to be higher than those of the samples subjected to heat treatment at pHc > pH > pHΦ1 . Based on the results obtained, it was concluded that E/1:2/3.80 and W/1:2/6.69 were the two complexes with finer droplet size distributions after preparation (26.72 ± 3.71 and 15.27 ± 1.01 µm, respectively) and after one week of storage at 4 °C (30.71 ± 1.57 and 28.79 ± 0.56 µm, respectively) than others. Apparent viscosities of electrostatic and wet-heated complexes and emulsions made with the complexes were measured. Protein-polysaccharide interactions can be used as an efficient way for producing novel emulsifiers/stabilisers after heat treatment. © 2016 Society of Chemical Industry. © 2016 Society of Chemical Industry.

  15. The lithium vapor box divertor

    SciTech Connect

    Goldston, R. J.; Myers, R.; Schwartz, J.

    2016-01-13

    It has long been recognized that volumetric dissipation of the plasma heat flux from a fusion power system is preferable to its localized impingement on a material surface. Volumetric dissipation mitigates both the anticipated very high heat flux and intense particle-induced damage due to sputtering. Our recent projections to a tokamak demonstration power plant suggest an immense upstream parallel heat flux, of order 20 GW m-2, implying that fully detached operation may be a requirement for the success of fusion power. Building on pioneering work on the use of lithium by Nagayama et al and by Ono et al as well as earlier work on the gas box divertor by Watkins and Rebut, we present here a concept for a lithium vapor box divertor, in which lithium vapor extracts momentum and energy from a fusion-power-plant divertor plasma, using fully volumetric processes. Furthermore, at the high powers and pressures that are projected this requires a high density of lithium vapor, which must be isolated from the main plasma in order to avoid lithium build-up on the chamber walls or in the plasma. Isolation is achieved through a powerful multi-box differential pumping scheme available only for condensable vapors. The preliminary box-wise calculations are encouraging, but much more work is required in order to demonstrate the practical viability of this scheme, taking into account at least 2D plasma and vapor flows within and between the vapor boxes and out of the vapor boxes to the main plasma.

  16. The lithium vapor box divertor

    DOE PAGES

    Goldston, R. J.; Myers, R.; Schwartz, J.

    2016-01-13

    It has long been recognized that volumetric dissipation of the plasma heat flux from a fusion power system is preferable to its localized impingement on a material surface. Volumetric dissipation mitigates both the anticipated very high heat flux and intense particle-induced damage due to sputtering. Our recent projections to a tokamak demonstration power plant suggest an immense upstream parallel heat flux, of order 20 GW m-2, implying that fully detached operation may be a requirement for the success of fusion power. Building on pioneering work on the use of lithium by Nagayama et al and by Ono et al asmore » well as earlier work on the gas box divertor by Watkins and Rebut, we present here a concept for a lithium vapor box divertor, in which lithium vapor extracts momentum and energy from a fusion-power-plant divertor plasma, using fully volumetric processes. Furthermore, at the high powers and pressures that are projected this requires a high density of lithium vapor, which must be isolated from the main plasma in order to avoid lithium build-up on the chamber walls or in the plasma. Isolation is achieved through a powerful multi-box differential pumping scheme available only for condensable vapors. The preliminary box-wise calculations are encouraging, but much more work is required in order to demonstrate the practical viability of this scheme, taking into account at least 2D plasma and vapor flows within and between the vapor boxes and out of the vapor boxes to the main plasma.« less

  17. Air heating system

    DOEpatents

    Primeau, John J.

    1983-03-01

    A self-starting, fuel-fired, air heating system including a vapor generator, a turbine, and a condenser connected in a closed circuit such that the vapor output from the vapor generator is conducted to the turbine and then to the condenser where it is condensed for return to the vapor generator. The turbine drives an air blower which passes air over the condenser for cooling the condenser. Also, a condensate pump is driven by the turbine. The disclosure is particularly concerned with the provision of heat exchanger and circuitry for cooling the condensed fluid output from the pump prior to its return to the vapor generator.

  18. Specific Genetic Immunotherapy Induced by Recombinant Vaccine Alpha-Fetoprotein-Heat Shock Protein 70 Complex

    NASA Astrophysics Data System (ADS)

    Wang, Xiaoping; Lin, Huanping; Wang, Qiaoxia

    Purposes: To construct a recombinant vaccine alpha-fetoprotein (AFP)-heat shock protein (HSP70) complex, and study its ability to induce specific CTL response and its protective effect against AFP-producing tumor. Material/Methods: A recombinant vaccine was constructed by conjugating mouse alpha-fetoprotein to heat shock protein 70. By way of intracutaneous injection, mice were primed and boosted with recombinant vaccine mAFP/HSP70, whereas single mAFP or HSP70 injection as controls. The ELISPOT and ELISA were used to measure the frequency of cells producing the cytokine IFN-γ in splenocytes and the level of anti-AFP antibody of serum from immunized mice respectively. In vivo tumor challenge were carried out to assess the immune effect of the recombinant vaccine. Results: By recombinant mAFP/HSP70 vaccine immunization, the results of ELISPOT and ELISA showed that the number of splenic cells producing IFN-γ and the level of anti-AFP antibody of serum were significantly higher in mAFP/HSP70 group than those in mAFP and HSP70 groups (108.50±11.70 IFN-γ spots/106 cells vs 41.60±10.40 IFN-γ spots/106 cells, 7.32±3.14 IFN-γ spots/106 cells, P<0.01; 156.32±10.42 μg/mL vs 66.52±7.35 μg/mL, 5.73±2.89 μg/mL, P<0.01). The tumor volume in mAFP/HSP70 group was significantly smaller than that in mAFP and HSP70 groups (42.44±7.14 mm3 vs 392.23±12.46 mm3, 838.63±13.84 mm3, P<0.01). Conclusions: The study further confirmed the function of heat shock protein 70's immune adjuvant. Sequential immunization with recombinant mAFP/HSP70 vaccine could generate effective antitumor immunity on AFP-producing tumor. The recombined mAFP/HSP70 vaccine may be suitable for serving as an immunotherapy for hepatocellular carcinoma.

  19. Chemical vapor infiltration using microwave energy

    DOEpatents

    Devlin, David J.; Currier, Robert P.; Laia, Jr., Joseph R.; Barbero, Robert S.

    1993-01-01

    A method for producing reinforced ceramic composite articles by means of chemical vapor infiltration and deposition in which an inverted temperature gradient is utilized. Microwave energy is the source of heat for the process.

  20. Very focused expulsion of pore fluid along the western Nankai accreionary complex detected by closely-spaced heat flow measurements

    NASA Astrophysics Data System (ADS)

    Kinoshita, M.; Goto, S.; Gulick, S. P.; Mikada, H.

    2002-12-01

    During the KR02-10 cruise onboard R/V KAIREI, JAMSTEC, intensive heat flow measurements were carried out across the western and middle Nankai Trough areas, in order to reveal thermal and hydrological process across the frontal thrust and the Large Thrust Slice Zone (LTSZ). Previous heat flow data suggest that the Nankai accretionary complex is basically thermal-conduction dominant, except for strongly channelized flow along the faults. Heat flow was measured using two types of geothermal probes: a 4.5m geothermal probe lowered from the ship, and two 60cm probes manipulated by ROV KAIKO. Probe positions were controlled using SSBL acoustic navigation with the accuracy of 30-70 m. We obtained 19 heat flow data across the second frontal thrust off Muroto. Heat flow is highest at the base of the second frontal thrust. Maximum heat flow reaches up to 280 mW/m2 and its width is probably less than 50 m. We observed no indication of seepage activity at this site. Upslope we found a cold seep site, which was distributed along a topographic contour of 4620 m. Although we measured heat flow in the middle of seep site, no heat flow anomaly was detected. We obtained 12 heat flow data across the lower part of LTSZ off Muroto. Two local heat flow anomalies of up to 250 mW/m2 were detected, both of which are related to cold seep activities. The amplitude of heat flow anomalies is similar to that observed in the frontal thrust area, although the basal heat flow here, 60-80 mW/m2, is much lower that in the frontal thrust area. Also, the width of the anomaly seems similar to frontal thrust area. These data indicates that fluid flow is restricted within the fault or in the hanging wall, and otherwise the thermal regime in the accretionary complex is conduction dominant. On the other hand, difference in heat flow anomaly locations between two areas may provide insights into the maturity of cold seep activity and the thrust as fluid conduits.

  1. Axially grooved heat pipe study

    NASA Technical Reports Server (NTRS)

    1977-01-01

    A technology evaluation study on axially grooved heat pipes is presented. The state-of-the-art is reviewed and present and future requirements are identified. Analytical models, the Groove Analysis Program (GAP) and a closed form solution, were developed to facilitate parametric performance evaluations. GAP provides a numerical solution of the differential equations which govern the hydrodynamic flow. The model accounts for liquid recession, liquid/vapor shear interaction, puddle flow as well as laminar and turbulent vapor flow conditions. The closed form solution was developed to reduce computation time and complexity in parametric evaluations. It is applicable to laminar and ideal charge conditions, liquid/vapor shear interaction, and an empirical liquid flow factor which accounts for groove geometry and liquid recession effects. The validity of the closed form solution is verified by comparison with GAP predictions and measured data.

  2. Liquid-vapor flow regime transitions for use in design of heat transfer loops in spacecraft: An investigation of two-phase flow in zero gravity conditions

    NASA Astrophysics Data System (ADS)

    Lovell, T. W.

    1985-05-01

    The behavior of viscous (or low velocity) two-phase vapor-liquid flow under zero gravity was simulated in the laboratory by using two immiscible fluids of equal density flowing together in a one inch diameter glass tube. The fluids used were Polypropylene Glycol (PPG) which simulated the liquid phase and water which simulated the vapor phase. Various tests were conducted varying flow rates and entrance conditions. Four existing flow regime models were analyzed, modeled on a computer, and extrapolated to predict zero-gravity conditions. The flow regimes were the Horizontal Dukler-Taitel, Vertical Dukler-Taitel, Vertical Weisman and Horizontal Weisman. None of these models when extrapolated to zero-g conditions agreed well with the lab data, and some of the observed flow regimes were not predicted at all.

  3. Role of chalcogen vapor annealing in inducing bulk superconductivity in Fe1+yTe1-xSex [How does annealing in chalcogen vapor induce superconductivity in Fe1+yTe-xSex?

    DOE PAGES

    Lin, Wenzhi; Ganesh, P.; Gianfrancesco, Anthony; ...

    2015-02-01

    Recent investigations have shown that Fe1+yTe1-xSex can be made superconducting by annealing it in Se and O vapors. The current lore is that these chalcogen vapors induce superconductivity by removing the magnetic excess Fe atoms. To investigate this phenomenon we performed a combination of magnetic susceptibility, specific heat and transport measurements together with scanning tunneling microscopy and spectroscopy and density functional theory calculations on Fe1+yTe1-xSex treated with Te vapor. We conclude that the main role of the Te vapor is to quench the magnetic moments of the excess Fe atoms by forming FeTem (m ≥ 1) complexes. We show thatmore » the remaining FeTem complexes are still damaging to the superconductivity and therefore that their removal potentially could further improve superconductive properties in these compounds.« less

  4. Acoustic Behavior of Vapor Bubbles

    NASA Technical Reports Server (NTRS)

    Prosperetti, Andrea; Oguz, Hasan N.

    1996-01-01

    In a microgravity environment vapor bubbles generated at a boiling surface tend to remain near it for a long time. This affects the boiling heat transfer and in particular promotes an early transition to the highly inefficient film boiling regime. This paper describes the physical basis underlying attempts to remove the bubbles by means of pressure radiation forces.

  5. Complex-Difference Constrained Compressed Sensing Reconstruction for Accelerated PRF Thermometry with Application to MRI Induced RF Heating

    PubMed Central

    Cao, Zhipeng; Oh, Sukhoon; Otazo, Ricardo; Sica, Christopher T.; Griswold, Mark A.; Collins, Christopher M.

    2014-01-01

    Purpose Introduce a novel compressed sensing reconstruction method to accelerate proton resonance frequency (PRF) shift temperature imaging for MRI induced radiofrequency (RF) heating evaluation. Methods A compressed sensing approach that exploits sparsity of the complex difference between post-heating and baseline images is proposed to accelerate PRF temperature mapping. The method exploits the intra- and inter-image correlations to promote sparsity and remove shared aliasing artifacts. Validations were performed on simulations and retrospectively undersampled data acquired in ex-vivo and in-vivo studies by comparing performance with previously proposed techniques. Results The proposed complex difference constrained compressed sensing reconstruction method improved the reconstruction of smooth and local PRF temperature change images compared to various available reconstruction methods in a simulation study, a retrospective study with heating of a human forearm in vivo, and a retrospective study with heating of a sample of beef ex vivo . Conclusion Complex difference based compressed sensing with utilization of a fully-sampled baseline image improves the reconstruction accuracy for accelerated PRF thermometry. It can be used to improve the volumetric coverage and temporal resolution in evaluation of RF heating due to MRI, and may help facilitate and validate temperature-based methods for safety assurance. PMID:24753099

  6. Role of chalcogen vapor annealing in inducing bulk superconductivity in Fe1 +yTe1 -xSex

    NASA Astrophysics Data System (ADS)

    Lin, Wenzhi; Ganesh, P.; Gianfrancesco, Anthony; Wang, Jun; Berlijn, Tom; Maier, Thomas A.; Kalinin, Sergei V.; Sales, Brian C.; Pan, Minghu

    2015-02-01

    Recent investigations have shown that Fe1 +yTe1 -xSex can be made superconducting by annealing it in Se and O vapors. The current lore is that these chalcogen vapors induce superconductivity by removing the magnetic excess Fe atoms. To investigate this phenomenon, we performed a combination of magnetic susceptibility, specific heat, and transport measurements together with scanning tunneling microscopy and spectroscopy and density functional theory calculations on Fe1 +yTe1 -xSex treated with Te vapor. We conclude that the main role of the Te vapor is to quench the magnetic moments of the excess Fe atoms by forming FeTem (m ≥1 ) complexes. We show that the remaining FeTem complexes are still damaging to the superconductivity and therefore that their removal potentially could further improve superconductive properties in these compounds.

  7. Gastric cancer-derived heat shock protein-gp96 peptide complex enhances dendritic cell activation

    PubMed Central

    Lu, Wen-Wen; Zhang, Hong; Li, You-Ming; Ji, Feng

    2017-01-01

    AIM To investigate the role of heat shock protein (HSP)-glycoprotein (gp)96 in dendritic cells (DCs) and lymphocytes induction in gastric cancer (GC). METHODS Human GC cell lines KATOIII, MKN-28 and SGC-7901 were infected with adenovirus gp96 at a multiplicity of infection of 100. gp96-GC antigen peptide complexes were purified. MTT (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) assay, lactate dehydrogenase (LDH) release assay and enzyme-linked immunosorbent assay were used to determine allo-reactive T cell stimulation, natural killer (NK) cell activity and expression of cytokines (such as interleukin (IL)-10, IL-12, interferon (IFN)-γ and tumor necrosis factor (TNF)-α), respectively. Effect of cytotoxic T lymphocyte (CTL) on DCs incubated with HSP-gp96 was also evaluated by LDH release. All assays were performed in triplicate and the average values were reported. Comparison between groups was conducted using Student’s t test. RESULTS T cells incubated with HSP-gp96 exhibited a marked increase in proliferation in a dose-dependent manner (P < 0.05). NK cell activity after gp96-GC peptide complex treatment was significantly higher than that after antigen peptide treatment (P < 0.05). The activity of CTLs incubated with DCs from three GC cells lines was obviously higher than that stimulated by GC antigen at ratios of 50: 1, 25: 1, 10: 1, and 5: 1 (P < 0.05). Furthermore, the secretion of TNF-α, IL-10, IL-12 (P70) and IFN-γ markedly increased after incubation with HSP-gp96 (P < 0.05). CONCLUSION HSP-gp96 promotes T cell response, enhances DC antigen presentation and induces cytokine secretion, as well. HSP-gp96 has potential as immunotherapy for elimination of residual GC cells. PMID:28706421

  8. Fluid flow effects in evaporation from liquid-vapor meniscus

    SciTech Connect

    Khrustalev, D.; Faghri, A.

    1996-12-31

    A mathematical model of the evaporating liquid-vapor meniscus in a capillary slot has been developed. The model includes two-dimensional steady-state momentum conservation and energy equations for both the vapor and liquid phases, and incorporates the existing simplified one-dimensional model of the evaporating microfilm. The numerical results, obtained for water, demonstrate the importance of accounting for the fluid flow in calculating the effective evaporative heat transfer coefficient and the superheat of the vapor over the liquid-vapor meniscus due to the heat transfer from the heated wall. With higher heat fluxes, a recirculation zone appears in the vapor near the heated wall due to the extensive evaporation in the thin-film region of the liquid-vapor meniscus.

  9. Measuring the Heats of Water.

    ERIC Educational Resources Information Center

    Hunt, James L.; Tegart, Tracy L.

    1994-01-01

    Uses common equipment (tea kettle and vacuum bottles) to precisely measure the specific heat, latent heat of fusion, and latent heat of vaporization of water. Provides descriptions for all three experiments. (MVL)

  10. Measuring the Heats of Water.

    ERIC Educational Resources Information Center

    Hunt, James L.; Tegart, Tracy L.

    1994-01-01

    Uses common equipment (tea kettle and vacuum bottles) to precisely measure the specific heat, latent heat of fusion, and latent heat of vaporization of water. Provides descriptions for all three experiments. (MVL)

  11. Characterization and Physiological Function of Class I Low-Molecular-Mass, Heat-Shock Protein Complex in Soybean.

    PubMed

    Jinn, T. L.; Chen, Y. M.; Lin, C. Y.

    1995-06-01

    Examination of an ammonium sulfate-enriched fraction (70-100% saturation) of heat-shock proteins (HSPs) by nondenaturing polyacrylamide gel electrophoresis revealed the presence of a high molecular mass complex (280 kD) in soybean (Glycine max) seedlings. This complex cross-reacted with antibodies raised against soybean class I low-molecular-mass (LMW) HSPs. Dissociation of the complex by denaturing polyacrylamide gel electrophoresis showed the complex to contain at least 15 polypeptides of the 15-to 18-kD class I LMW HSPs that could be detected by staining, radiolabeling, and western blotting. A similar LMW-HSP complex was observed in mung bean (Vigna radiata L.; 295 kD), in pea (Pisum sativum L.; 270 kD), and in rice (Oryza sativa L.; 310 kD). The complex was stable under high salt conditions (250 mM KCI), and the integrity was not affected by 1% Nonidet P-40 and 3 [mu]g/ML RNase treatment. The size of the isolated HSP complex in vitro was conserved to 55[deg]C; however, starting at 37.5[deg]C, it changed to higher molecular forms in the presence of soluble proteins. The isolated HSP complex was able to protect up to 75% of the soluble proteins from heat denaturation in vitro.

  12. Methodology for comparison of hydraulic and thermal performance of alternative heat transfer fluids in complex systems

    SciTech Connect

    Ghajar, A.J.; Tang, W.C.; Beam, J.E.

    1995-01-01

    A general method for the comparison of hydraulic and thermal performance of different liquid coolants in complex systems is offered. As a case study, the performance of polyalphaolefin (PAO) and a silicate ester-based fluid (Coolanol 25R) used as liquid coolants in avionic systems is presented. Thermophysical property expressions for the variation of density, specific heat, thermal conductivity, and kinematic viscosity with temperature for PAO and Coolanol 25R were developed. The range of temperature for this study was from {minus}54 to 135 C. Based on the results, the hydraulic performance of Coolanol 25R is much better than that of PAO at low temperatures (below 0 C) and in the laminar flow regime. In the turbulent region, PAO outperforms Coolanol 25R hydraulically over the entire temperature range. The thermal performance of PAO at temperatures below 61 C and in the laminar flow region is slightly better than that of Coolanol 25R. In the low-temperature turbulent region, Coolanol 25R outperforms PAO thermally. At other temperatures, the performance of the two liquid coolants is reasonably close and fairly independent of the flow regime.

  13. Heat-Transfer Coupling For Heat Pipes

    NASA Technical Reports Server (NTRS)

    Nesmith, Bill J.

    1991-01-01

    Proposed welded heat-transfer coupling joins set of heat pipes to thermoelectric converter. Design avoids difficult brazing operation. Includes pair of mating flanged cups. Upper cup integral part of housing of thermoelectric converter, while lower cup integral part of plate supporting filled heat pipes. Heat pipes prefilled. Heat of welding applied around periphery of coupling, far enough from heat pipes so it would not degrade working fluid or create excessive vapor pressure in the pipes.

  14. Gravity sensitivity of a resistojet water vaporizer

    NASA Technical Reports Server (NTRS)

    Morren, W. Earl

    1993-01-01

    A laboratory model of a water vaporizer for resistojet applications was designed, fabricated, and steady and transient characteristics were measured. Vaporizer operation was not impacted by rotation about a horizontal axis normal to its own. The vaporizer was operated under low and high accelerations aboard a jet aircraft for periods up to 25 s at flow rates ranging from 159(10)(exp -6) to 230(10)(exp -6) kg/s. Slight changes in inlet and outlet pressures and some heat exchanger temperatures were observed during the low-gravity tests. However, the results of these tests indicated probable compatibility of the vaporizer design tested with a low-gravity environment.

  15. Unstable heat pipes

    SciTech Connect

    McGuinness, M.J.; Pruess, K.

    1987-10-01

    Heat pipes are an important feature of models of vapor-dominated geothermal reservoirs. Numerical experiments reveal that a vapor-dominated heat pipe is unstable if pressure is controlled at shallow levels. This instability is discussed in physical terms, and some implications for geothermal reservoirs are considered. 9 refs., 10 figs.

  16. Power production with two-phase expansion through vapor dome

    SciTech Connect

    Amend, W.E.; Toner, S.J.

    1984-08-07

    In a system wherein a fluid exhibits a regressive vapor dome in a T-S diagram, the following are provided: a two-phase nozzle receiving the fluid in pressurized and heated liquid state and expanding the received liquid into saturated or superheated vapor state, and apparatus receiving the saturated or superheated vapor to convert the kinetic energy thereof into power.

  17. Large-capacity pump vaporizer for liquid hydrogen and nitrogen

    NASA Technical Reports Server (NTRS)

    Hauser, J. A.

    1970-01-01

    Pump vaporizer system delivers 500 standard cubic feet per minute of hydrogen or nitrogen, one system delivers both gases. Vacuum-jacketed pump discharges liquid hydrogen or liquid nitrogen into vaporizing system heated by ambient air. Principal characteristics of the flow and discharge system, pump, and vaporizer are given.

  18. Nonazeotropic Heat Pump

    NASA Technical Reports Server (NTRS)

    Ealker, David H.; Deming, Glenn

    1991-01-01

    Heat pump collects heat from water circulating in heat-rejection loop, raises temperature of collected heat, and transfers collected heat to water in separate pipe. Includes sealed motor/compressor with cooling coils, evaporator, and condenser, all mounted in outer housing. Gradients of temperature in evaporator and condenser increase heat-transfer efficiency of vapor-compression cycle. Intended to recover relatively-low-temperature waste heat and use it to make hot water.

  19. A numerical study of fluid flow and heat transfer over a fin and flat tube heat exchangers with complex vortex generators

    NASA Astrophysics Data System (ADS)

    Sahel, Djamel; Ameur, Houari; Kamla, Youcef

    2017-05-01

    A numerical work is carried out to investigate the heat transfer and fluid flow behaviors in a fin-and-flat-tube heat exchanger provided with complex vortex generators (CVGs). A new design of CVGs is proposed in the present paper, it consists of CVGs formed by two portions: a flat portion with various attack angles (β = 0°, 20°, 40° and 60°) and a curved portion with various curvature angles (α = 30°, 45° and 60°). Changes in CVGs position ratio (R*) inside the tube are also investigated and three values of R* are considered, namely: R* = 1.375, 1.750 and 2.125. Computations based on the finite volume method with the SIMPLE algorithm are conducted for the air flow. The Reynolds number is ranging from 25 to 400. The obtained results show that the vortex formed near the tubes is intensified by the flat potion of CVGs, and the curved tube guide the fluid flow towards the region behind the tubes, resulting thus in improved heat transfer rates. In a comparison with tubes without CVG, the new design suggested and especially the case with β = 60°, α = 60° and R* = 2.125 improve significantly the heat transfer (an increase by about 76%) with a moderate pressure loss penalty. Contribution to the topical issue "Materials for Energy harvesting, conversion and storage II (ICOME 2016)", edited by Jean-Michel Nunzi, Rachid Bennacer and Mohammed El Ganaoui

  20. Is Heat Generated from a Crematorium an Appropriate Source for District Heating? Student Teachers' Reasoning About a Complex Environmental Issue

    ERIC Educational Resources Information Center

    Ekborg, Margareta

    2005-01-01

    This paper reports on a longitudinal study on how science student teachers' reasoning about a complex environmental issue developed through a teacher education programme in mathematics and science for grades 1-7 (ages 7-13). Of special interest was to follow the ways in which student teachers used scientific knowledge in their reasoning. The issue…

  1. Is Heat Generated from a Crematorium an Appropriate Source for District Heating? Student Teachers' Reasoning About a Complex Environmental Issue

    ERIC Educational Resources Information Center

    Ekborg, Margareta

    2005-01-01

    This paper reports on a longitudinal study on how science student teachers' reasoning about a complex environmental issue developed through a teacher education programme in mathematics and science for grades 1-7 (ages 7-13). Of special interest was to follow the ways in which student teachers used scientific knowledge in their reasoning. The issue…

  2. Process for vaporizing a liquid hydrocarbon fuel

    DOEpatents

    Szydlowski, Donald F.; Kuzminskas, Vaidotas; Bittner, Joseph E.

    1981-01-01

    The object of the invention is to provide a process for vaporizing liquid hydrocarbon fuels efficiently and without the formation of carbon residue on the apparatus used. The process includes simultaneously passing the liquid fuel and an inert hot gas downwardly through a plurality of vertically spaed apart regions of high surface area packing material. The liquid thinly coats the packing surface, and the sensible heat of the hot gas vaporizes this coating of liquid. Unvaporized liquid passing through one region of packing is uniformly redistributed over the top surface of the next region until all fuel has been vaporized using only the sensible heat of the hot gas stream.

  3. Effects of supplemental zinc amino acid complex on gut integrity in heat-stressed growing pigs.

    PubMed

    Sanz Fernandez, M V; Pearce, S C; Gabler, N K; Patience, J F; Wilson, M E; Socha, M T; Torrison, J L; Rhoads, R P; Baumgard, L H

    2014-01-01

    Heat stress (HS) jeopardizes livestock health and productivity and both may in part be mediated by reduced intestinal integrity. Dietary zinc improves a variety of bowel diseases, which are characterized by increased intestinal permeability. Study objectives were to evaluate the effects of supplemental zinc amino acid complex (ZnAA) on intestinal integrity in heat-stressed growing pigs. Crossbred gilts (43±6 kg BW) were ad libitum fed one of three diets: (1) control (ZnC; 120 ppm Zn as ZnSO4; n=13), (2) control+100 ppm Zn as ZnAA (Zn220; containing a total of 220 ppm Zn; n=14), and (3) control+200 ppm Zn as ZnAA (Zn320; containing a total of 320 ppm Zn; n=16). After 25 days on their respective diets, all pigs were exposed to constant HS conditions (36°C, ∼50% humidity) for either 1 or 7 days. At the end of the environmental exposure, pigs were euthanized and blood and intestinal tissues were harvested immediately after sacrifice. As expected, HS increased rectal temperature (P⩽0.01; 40.23°C v. 38.93°C) and respiratory rate (P⩽0.01; 113 v. 36 bpm). Pigs receiving ZnAA tended to have increased rectal temperature (P=0.07; +0.27°C) compared with ZnC-fed pigs. HS markedly reduced feed intake (FI; P⩽0.01; 59%) and caused BW loss (2.10 kg), but neither variable was affected by dietary treatment. Fresh intestinal segments were assessed ex vivo for intestinal integrity. As HS progressed from days 1 to 7, both ileal and colonic transepithelial electrical resistance (TER) decreased (P⩽0.05; 34% and 22%, respectively). This was mirrored by an increase in ileal and colonic permeability to the macromolecule dextran (P⩽0.01; 13- and 56-fold, respectively), and increased colonic lipopolysaccharide permeability (P⩽0.05; threefold) with time. There was a quadratic response (P⩽0.05) to increasing ZnAA on ileal TER, as it was improved (P⩽0.05; 56%) in Zn220-fed pigs compared with ZnC. This study demonstrates that HS progressively compromises the intestinal

  4. Complex difference constrained compressed sensing reconstruction for accelerated PRF thermometry with application to MRI-induced RF heating.

    PubMed

    Cao, Zhipeng; Oh, Sukhoon; Otazo, Ricardo; Sica, Christopher T; Griswold, Mark A; Collins, Christopher M

    2015-04-01

    Introduce a novel compressed sensing reconstruction method to accelerate proton resonance frequency shift temperature imaging for MRI-induced radiofrequency heating evaluation. A compressed sensing approach that exploits sparsity of the complex difference between postheating and baseline images is proposed to accelerate proton resonance frequency temperature mapping. The method exploits the intra-image and inter-image correlations to promote sparsity and remove shared aliasing artifacts. Validations were performed on simulations and retrospectively undersampled data acquired in ex vivo and in vivo studies by comparing performance with previously published techniques. The proposed complex difference constrained compressed sensing reconstruction method improved the reconstruction of smooth and local proton resonance frequency temperature change images compared to various available reconstruction methods in a simulation study, a retrospective study with heating of a human forearm in vivo, and a retrospective study with heating of a sample of beef ex vivo. Complex difference based compressed sensing with utilization of a fully sampled baseline image improves the reconstruction accuracy for accelerated proton resonance frequency thermometry. It can be used to improve the volumetric coverage and temporal resolution in evaluation of radiofrequency heating due to MRI, and may help facilitate and validate temperature-based methods for safety assurance. © 2014 Wiley Periodicals, Inc.

  5. Control of flow through a vapor generator

    DOEpatents

    Radcliff, Thomas D.

    2005-11-08

    In a Rankine cycle system wherein a vapor generator receives heat from exhaust gases, provision is made to avoid overheating of the refrigerant during ORC system shut down while at the same time preventing condensation of those gases within the vapor generator when its temperature drops below a threshold temperature by diverting the flow of hot gases to ambient and to thereby draw ambient air through the vapor generator in the process. In one embodiment, a bistable ejector is adjustable between one position, in which the hot gases flow through the vapor generator, to another position wherein the gases are diverted away from the vapor generator. Another embodiment provides for a fixed valve ejector with a bias towards discharging to ambient, but with a fan on the downstream side of said vapor generator for overcoming this bias.

  6. Cluster model of aluminum dense vapor plasma

    NASA Astrophysics Data System (ADS)

    Khomkin, A. L.; Shumikhin, A. S.

    2009-08-01

    The chemical model of aluminum vapor plasma, that take into account the formation of neutral and charged clusters, is suggested. Caloric and thermal equations of state and composition of plasma were received using the available information about properties of metal clusters. It is shown, that aluminum vapors are clusterized with decrease of temperature and with increase of density. Pressure dependence on internal energy is calculated and comparison with experimental data is made. The important role of aluminum clusters, especially in an initial phase of the metals vapor heating, is demonstrated. It is shown, that the region of plasma clusterization in gaseous phase agree with known literature data for binodal of vapor-liquid transition from gaseous region. Suggested cluster model may be used to forecast the location of metal vapors binodal. The conductivity of aluminum vapor plasma was calculated. The satisfactory agreement with available experimental data is received.

  7. A software system used for load distribution at a combined heat and power plant with the complex mix of the equipment and complex schemes of heat and electric power supply

    NASA Astrophysics Data System (ADS)

    Makarch'yan, V. A.; Chernyaev, A. N.; Andryushin, A. V.; Pechenkin, S. P.; Lisitsa, V. I.; Logvinov, E. I.; Molchanov, A. Yu.

    2013-05-01

    The authors describe various approaches to construction of an algorithm for the solution of the problem of load distribution at a combined heat and power (CHP) plant with the complex mix of the equipment and complex schemes of heat and electrical energy supply on the basis of which the software system has been developed. Methods of obtaining energy characteristics of the equipment used for solving the problem of load distribution were studied. The results of the implementation of the software system for load distribution at the CHP-23 plant belonging to OAO Mosenergo are given. Realization of recommendations on maintaining an operational mode of the equipment with due regard for its optimal loading makes it possible to obtain fuel savings of up to 1%.

  8. The Optical Characteristics of Nitrogen-Doped Amorphous Carbon Thin-Films Grown on Novel Heat-Tolerant Flexible Plastic Substrates by a Newly Developed Microwave Surface Wave Plasma Chemical Vapor Deposition Method

    NASA Astrophysics Data System (ADS)

    Rusop, M.; Omer, A. M. M.; Adhikari, S.; Adhikary, S.; Uchida, H.; Soga, T.; Jimbo, T.; Umeno, M.

    Nitrogen-doped amorphous carbon (a-C:N) thin-films have been deposited on novel heat tolerant flexible plastic substrates by a newly developed microwave surface wave plasma chemical vapor deposition (MWSWP-CVD) method. Methane gas and also camphor dissolved with ethyl alcohol gas composition have been used as plasma source. Nitrogen gas has been used as a dopant material for a-C:N films. In this paper, the optical characteristics of absorption coefficients and band gaps for a-C:N are discussed. The optical band gap of a-C:N films was found to be approximately 1.7 eV, which is close to the suitable band gap for solar cell. The optical band gap of a-C:N was found to be dependent on the composition gas source pressures.

  9. High heat flux loop heat pipes

    NASA Technical Reports Server (NTRS)

    North, Mark T.; Sarraf, David B.; Rosenfeld, John H.; Maidanik, Yuri F.; Vershinin, Sergey

    1997-01-01

    Loop heat pipes (LHPs) can transport very large thermal power loads over long distances, through flexible, small diameter tubes against gravitational heads. In order to overcome the evaporator limit of LHPs, which is of about 0.07 MW/sq m, work was carried out to improve the efficiency by threefold to tenfold. The vapor passage geometry for the high heat flux conditions is shown. A bidisperse wick material within the circumferential vapor passages was used. Along with heat flux enhancement, several underlying issues were demonstrated, including the fabrication of bidisperse powder with controlled properties and the fabrication of a device geometry capable of replacing vapor passages with bidisperse powder.

  10. Vacuum-Induction, Vacuum-Arc, and Air-Induction Melting of a Complex Heat-Resistant Alloy

    NASA Technical Reports Server (NTRS)

    Decker, R. F.; Rowe, John P.; Freeman, J. W.

    1959-01-01

    The relative hot-workability and creep-rupture properties at 1600 F of a complex 55Ni-20Cr-15Co-4Mo-3Ti-3Al alloy were evaluated for vacuum-induction, vacuum-arc, and air-induction melting. A limited study of the role of oxygen and nitrogen and the structural effects in the alloy associated with the melting process was carried out. The results showed that the level of boron and/or zirconium was far more influential on properties than the melting method. Vacuum melting did reduce corner cracking and improve surface during hot-rolling. It also resulted in more uniform properties within heats. The creep-rupture properties were slightly superior in vacuum heats at low boron plus zirconium or in heats with zirconium. There was little advantage at high boron levels and air heats were superior at high levels of boron plus zirconium. Vacuum heats also had fewer oxide and carbonitride inclusions although this was a function of the opportunity for separation of the inclusions from high oxygen plus nitrogen heats. The removal of phosphorous by vacuum melting was not found to be related to properties. Oxygen plus nitrogen appeared to increase ductility in creep-rupture tests suggesting that vacuum melting removes unidentified elements detrimental to ductility. Oxides and carbonitrides in themselves did not initiate microcracks. Carbonitrides in the grain boundaries of air heats did initiate microcracks. The role of microcracking from this source and as a function of oxygen and nitrogen content was not clear. Oxygen and nitrogen did intensify corner cracking during hot-rolling but were not responsible for poor surface which resulted from rolling heats melted in air.

  11. Experimental and Computational Studies of Heat Transfer in Complex Internal Flows.

    DTIC Science & Technology

    1981-01-01

    isolated plexi - glass struts (not shown in the figure) bridged the gap just under the plastic sheet C. Direct contact between the two aluminum walls...the plexi - glass wall as at the other walls. The numerical solutions for the plexiglass wall yield the rate at which heat passes out of the heated walls

  12. Petroleum Vapor Intrusion

    EPA Pesticide Factsheets

    One type of vapor intrusion is PVI, in which vapors from petroleum hydrocarbons such as gasoline, diesel, or jet fuel enter a building. Intrusion of contaminant vapors into indoor spaces is of concern.

  13. Processing of extraterrestrial materials by high temperature vacuum vaporization

    NASA Technical Reports Server (NTRS)

    Grimley, R. T.; Lipschutz, M. E.

    1983-01-01

    It is noted that problems associated with the extraction and concentration of elements and commpounds important for the construction and operation of space habitats have received little attention. High temperature vacuum vaporization is considered a promising approach; this is a technique for which the space environment offers advantages in the form of low ambient pressures and temperatures and the possibility of sustained high temperatures via solar thermal energy. To establish and refine this new technology, experimental determinations must be made of the material release profiles as a function of temperature, of the release kinetics and chemical forms of material being transported, and of the various means of altering release kinetics. Trace element data determined by neutron activation analysis of meteorites heated to 1400 C in vacuum is summarized. The principal tool, high temperature spectrometry, is used to examine the vaporization thermodynamics and kinetics of major and minor elements from complex multicomponent extraterrestrial materials.

  14. A laboratory study examining the impact of linen use on low-air-loss support surface heat and water vapor transmission rates.

    PubMed

    Williamson, Rachel; Lachenbruch, Charlie; VanGilder, Catherine

    2013-08-01

    Layers of linens are frequently placed under patients to manage moisture and/or assist with positioning immobile patients, including persons placed on a therapeutic surface because they are at risk for developing pressure ulcers. Because skin microclimate is believed to affect pressure ulcer risk, some therapeutic surfaces are designed to manage skin temperature and humidity (microclimate management). The purpose of this study was to measure the effects of linens and underpads on a low-air-loss (LAL) surface's ability to disperse heat and evaporate moisture. Underpads and transfer sheet combinations (grouped by three common linen functions: immobility, moisture management, and immobility and moisture management) were tested using the sweating guarded hot plate method, which allows for the measurement of the evaporative capacity (g H2O/m2*hour) and the total rate of heat withdrawal (Watts/m2) associated with nine different linen configurations placed on the support surface. Total heat withdrawal and evaporative capacity of the LAL surface with a fitted sheet only was used for comparison (P <0.05) Compared with fitted sheet only, heat withdrawal was significantly reduced by five of eight combinations, and evaporative moisture reduction was significantly reduced by six of eight linen combinations (P <0.05). All combinations that included plastic-containing underpads significantly reduced the surface's ability to dissipate heat and evaporate moisture, and use of the maximum number of layers (nine) reduced heat withdrawal to the level of a static, nonLAL surface. The results of this study suggest that putting additional linens or underpads on LAL surfaces may adversely affect skin temperature and moisture, thereby reducing the pressure ulcer prevention potential of these surfaces. Additional studies to examine the effect of linens and underpads as well as microclimate management strategies on pressure ulcer risk are needed.

  15. Superfund Vapor Intrusion

    EPA Pesticide Factsheets

    In addition to basic information about vapor intrusion, the site contains technical and policy documents, tools and other resources to support vapor intrusion environmental investigations and mitigation activities.

  16. The summer 2012 Greenland heat wave: In situ and remote sensing observations of water vapor isotopic composition during an atmospheric river event

    NASA Astrophysics Data System (ADS)

    Bonne, Jean-Louis; Steen-Larsen, Hans Christian; Risi, Camille; Werner, Martin; Sodemann, Harald; Lacour, Jean-Lionel; Fettweis, Xavier; Cesana, Grégory; Delmotte, Marc; Cattani, Olivier; Vallelonga, Paul; Kjær, Helle Astrid; Clerbaux, Cathy; Sveinbjörnsdóttir, Árny Erla; Masson-Delmotte, Valérie

    2015-04-01

    During 7-12 July 2012, extreme moist and warm conditions occurred over Greenland, leading to widespread surface melt. To investigate the physical processes during the atmospheric moisture transport of this event, we study the water vapor isotopic composition using surface in situ observations in Bermuda Island, South Greenland coast (Ivittuut), and northwest Greenland ice sheet (NEEM), as well as remote sensing observations (Infrared Atmospheric Sounding Interferometer (IASI) instrument on board MetOp-A), depicting propagation of similar surface and midtropospheric humidity and δD signals. Simulations using Lagrangian moisture source diagnostic and water tagging in a regional model showed that Greenland was affected by an atmospheric river transporting moisture from the western subtropical North Atlantic Ocean, which is coherent with observations of snow pit impurities deposited at NEEM. At Ivittuut, surface air temperature, humidity, and δD increases are observed. At NEEM, similar temperature increase is associated with a large and long-lasting ˜100‰δD enrichment and ˜15‰ deuterium excess decrease, thereby reaching Ivittuut level. We assess the simulation of this event in two isotope-enabled atmospheric general circulation models (LMDz-iso and ECHAM5-wiso). LMDz-iso correctly captures the timing of propagation for this event identified in IASI data but depict too gradual variations when compared to surface data. Both models reproduce the surface meteorological and isotopic values during the event but underestimate the background deuterium excess at NEEM. Cloud liquid water content parametrization in LMDz-iso poorly impacts the vapor isotopic composition. Our data demonstrate that during this atmospheric river event the deuterium excess signal is conserved from the moisture source to northwest Greenland.

  17. Theory of hysteresis during electron heating of electromagnetic wave scattering by self-organized dust structures in complex plasmas

    SciTech Connect

    Tsytovich, Vadim; Gusein-zade, Namik; Ignatov, Alexander

    2015-07-15

    Dust structuring is a natural and universal process in complex plasmas. The scattering of electromagnetic waves by dust structures is governed by the factor of coherency, i.e., the total number of coherent electrons in a single structure. In the present paper, we consider how the factor of coherency changes due to additional pulse electron heating and show that it obeys a hysteresis. After the end of the pulse heating, the scattering intensity differs substantially from that before heating. There are three necessary conditions for scattering hysteresis: first, the radiation wavelength should be larger than the pattern (structure) size; second, the total number of coherent electrons confined by the structure should be large; and third, the heating pulse duration should be shorter than the characteristic time of dust structure formation. We present the results of numerical calculations using existing models of self-consistent dust structures with either positively or negatively charged dust grains. It is shown that, depending on the grain charge and the ionization rate, two types of hysteresis are possible: one with a final increase of the scattering and the other with a final decrease of the scattering. It is suggested that the hysteresis of coherent scattering can be used as a tool in laboratory experiments and that it can be a basic mechanism explaining the observed hysteresis in radar scattering by noctilucent clouds during active experiments on electron heating in mesosphere.

  18. Solar heating and hot water system installed at Municipal Building complex, Abbeville, South Carolina

    NASA Technical Reports Server (NTRS)

    1979-01-01

    Information on the solar energy system installed at the new municipal building for the City of Abbeville, SC is presented, including a description of solar energy system and buildings, lessons learned, and recommendations. The solar space heating system is a direct air heating system. The flat roof collector panel was sized to provide 75% of the heating requirement based on an average day in January. The collectors used are job-built with two layers of filon corrugated fiberglass FRP panels cross lapped make up the cover. The storage consists of a pit filled with washed 3/4 in - 1 1/2 in diameter crushed granite stone. The air handler includes the air handling mechanism, motorized dampers, air circulating blower, sensors, control relays and mode control unit. Solar heating of water is provided only those times when the hot air in the collector is exhausted to the outside.

  19. Effects of friction and heat conduction on sound propagation in ducts. [analyzing complex aerodynamic noise problems

    NASA Technical Reports Server (NTRS)

    Huerre, P.; Karamcheti, K.

    1976-01-01

    The theory of sound propagation is examined in a viscous, heat-conducting fluid, initially at rest and in a uniform state, and contained in a rigid, impermeable duct with isothermal walls. Topics covered include: (1) theoretical formulation of the small amplitude fluctuating motions of a viscous, heat-conducting and compressible fluid; (2) sound propagation in a two dimensional duct; and (3) perturbation study of the inplane modes.

  20. Complex fluid flow and heat transfer analysis inside a calandria based reactor using CFD technique

    NASA Astrophysics Data System (ADS)

    Kulkarni, P. S.

    2017-04-01

    Series of numerical experiments have been carried out on a calandria based reactor for optimizing the design to increase the overall heat transfer efficiency by using Computational Fluid Dynamic (CFD) technique. Fluid flow and heat transfer inside the calandria is governed by many geometric and flow parameters like orientation of inlet, inlet mass flow rate, fuel channel configuration (in-line, staggered, etc.,), location of inlet and outlet, etc.,. It was well established that heat transfer is more wherever forced convection dominates but for geometries like calandria it is very difficult to achieve forced convection flow everywhere, intern it strongly depends on the direction of inlet jet. In the present paper the initial design was optimized with respect to inlet jet angle, the optimized design has been numerically tested for different heat load mass flow conditions. To further increase the heat removal capacity of a calandria, further numerical studies has been carried out for different inlet geometry. In all the analysis same overall geometry size and same number of tubes has been considered. The work gives good insight into the fluid flow and heat transfer inside the calandria and offer a guideline for optimizing the design and/or capacity enhancement of a present design.

  1. The Lithium Vapor Box Divertor

    NASA Astrophysics Data System (ADS)

    Goldston, Robert; Hakim, Ammar; Hammett, Gregory; Jaworski, Michael; Myers, Rachel; Schwartz, Jacob

    2015-11-01

    Projections of scrape-off layer width to a demonstration power plant suggest an immense parallel heat flux, of order 12 GW/m2, which will necessitate nearly fully detached operation. Building on earlier work by Nagayama et al. and by Ono et al., we propose to use a series of differentially pumped boxes filled with lithium vapor to isolate the buffering vapor from the main plasma chamber, allowing stable detachment. This powerful differential pumping is only available for condensable vapors, not conventional gases. We demonstrate the properties of such a system through conservation laws for vapor mass and enthalpy, and then include plasma entrainment and ultimately an estimate of radiated power. We find that full detachment should be achievable with little leakage of lithium to the main plasma chamber. We also present progress towards solving the Navier-Stokes equation numerically for the chain of vapor boxes, including self-consistent wall boundary conditions and fully-developed shocks, as well as concepts for an initial experimental demonstration-of-concept. This work supported by DOE Contract No. DE-AC02-09CH11466.

  2. Complexation of rice starch/flour and maize oil through heat moisture treatment: Structural, in vitro digestion and physicochemical properties.

    PubMed

    Chen, Xu; He, Xiaowei; Fu, Xiong; Zhang, Bin; Huang, Qiang

    2017-05-01

    This study investigated structural, in vitro digestion and physicochemical properties of normal rice starch (NRS)/flour (NRF) complexed with maize oil (MO) through heat-moisture treatment (HMT). The NRS-/NRF-MO complex displayed an increased pasting temperature and a decreased peak viscosity. After HMT, less ordered Maltese and more granule fragments were observed for NRS-/NRF-MO complex. Meanwhile, more aggregation was observed in the HMT samples with higher moisture contents. We found that higher onset temperature, lower enthalpy change and relative crystallinity of the NRS-/NRF-MO complex were associated with a higher moisture content of HMT samples. The higher moisture content of HMT was also favorable for the amylose-lipid complex formation. Differences in starch digestion properties were found for NRS-MO and NRF-MO complex. All of the NRS/NRF complexed MO after cooking showed lower rapidly digestible starch (RDS) contents compared with the control sample, therein NRS-/NRF- MO 20% exhibited the highest sum of the slowly digestible starch and resistant starch contents. In general, HMT had a greater impact on the in vitro digestion and physicochemical properties of flour samples compared with starch counterparts. Copyright © 2017 Elsevier B.V. All rights reserved.

  3. Distribution of Chlorophyll-Protein Complexes during Chilling in the Light Compared with Heat-Induced Modifications 1

    PubMed Central

    Ovaska, Jari; Mäenpää, Pirkko; Nurmi, Arja; Aro, Eva-Mari

    1990-01-01

    The effects of chilling in the light (4 days at 5°C and 100-200 micromoles of photons per square meter per second) on the distribution of chlorophyll (Chl) protein complexes between appressed and nonappressed thylakoid regions of pumpkin (Cucurbita pepo L.) chloroplasts were studied and compared with the changes occurring during in vitro heat treatment (5 minutes at 40°C) of isolated thylakoids. Both treatments induced an increase (18 and 65%, respectively) in the relative amount of the antenna Chl a protein complexes (CP47 + CP43) of photosystem II (PSII) in stroma lamellae vesicles. Freeze-fracture replicas of light-chilled material revealed an increase in the particle density on the exoplasmic fracture face of unstacked membrane regions. These two treatments differed markedly, however, in respect to comigration of the light-harvesting Chl a/b protein complex (LHCII) of PSII. The LHCII/PSII ratio in stroma lamellae vesicles remained fairly constant during chilling in the light, whereas it dropped during the heat treatment. Moreover, it was a minor light-harvesting Chl a/b protein complex of PSII, CP29, that increased most in stroma lamellae vesicles during light-chilling. Changes in the organization of LHCII during chilling were suggested by a shift to particles of smaller sizes on the protoplasmic fracture face of stacked membrane regions and a decrease in the amount of trans-Δ3-hexadecenoic acid in the phosphatidyldiacylglycerol fraction. Images Figure 2 PMID:16667464

  4. Enhanced Photoluminescence and Raman Properties of Al-Doped ZnO Nanostructures Prepared Using Thermal Chemical Vapor Deposition of Methanol Assisted with Heated Brass

    PubMed Central

    Thandavan, Tamil Many K.; Gani, Siti Meriam Abdul; San Wong, Chiow; Md. Nor, Roslan

    2015-01-01

    Vapor phase transport (VPT) assisted by mixture of methanol and acetone via thermal evaporation of brass (CuZn) was used to prepare un-doped and Al-doped zinc oxide (ZnO) nanostructures (NSs). The structure and morphology were characterized by field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). Photoluminescence (PL) properties of un-doped and Al-doped ZnO showed significant changes in the optical properties providing evidence for several types of defects such as zinc interstitials (Zni), oxygen interstitials (Oi), zinc vacancy (Vzn), singly charged zinc vacancy (VZn-), oxygen vacancy (Vo), singly charged oxygen vacancy (Vo+) and oxygen anti-site defects (OZn) in the grown NSs. The Al-doped ZnO NSs have exhibited shifted PL peaks at near band edge (NBE) and red luminescence compared to the un-doped ZnO. The Raman scattering results provided evidence of Al doping into the ZnO NSs due to peak shift from 145 cm-1 to an anomalous peak at 138 cm-1. Presence of enhanced Raman signal at around 274 and 743 cm-1 further confirmed Al in ZnO NSs. The enhanced D and G band in all Al-doped ZnO NSs shows possible functionalization and doping process in ZnO NSs. PMID:25756598

  5. Enhanced photoluminescence and Raman properties of Al-Doped ZnO nanostructures prepared using thermal chemical vapor deposition of methanol assisted with heated brass.

    PubMed

    Thandavan, Tamil Many K; Gani, Siti Meriam Abdul; San Wong, Chiow; Md Nor, Roslan

    2015-01-01

    Vapor phase transport (VPT) assisted by mixture of methanol and acetone via thermal evaporation of brass (CuZn) was used to prepare un-doped and Al-doped zinc oxide (ZnO) nanostructures (NSs). The structure and morphology were characterized by field emission scanning electron microscopy (FESEM) and x-ray diffraction (XRD). Photoluminescence (PL) properties of un-doped and Al-doped ZnO showed significant changes in the optical properties providing evidence for several types of defects such as zinc interstitials (Zni), oxygen interstitials (Oi), zinc vacancy (Vzn), singly charged zinc vacancy (VZn-), oxygen vacancy (Vo), singly charged oxygen vacancy (Vo+) and oxygen anti-site defects (OZn) in the grown NSs. The Al-doped ZnO NSs have exhibited shifted PL peaks at near band edge (NBE) and red luminescence compared to the un-doped ZnO. The Raman scattering results provided evidence of Al doping into the ZnO NSs due to peak shift from 145 cm-1 to an anomalous peak at 138 cm-1. Presence of enhanced Raman signal at around 274 and 743 cm-1 further confirmed Al in ZnO NSs. The enhanced D and G band in all Al-doped ZnO NSs shows possible functionalization and doping process in ZnO NSs.

  6. Simple Chemical Vapor Deposition Experiment

    ERIC Educational Resources Information Center

    Pedersen, Henrik

    2014-01-01

    Chemical vapor deposition (CVD) is a process commonly used for the synthesis of thin films for several important technological applications, for example, microelectronics, hard coatings, and smart windows. Unfortunately, the complexity and prohibitive cost of CVD equipment makes it seldom available for undergraduate chemistry students. Here, a…

  7. Simple Chemical Vapor Deposition Experiment

    ERIC Educational Resources Information Center

    Pedersen, Henrik

    2014-01-01

    Chemical vapor deposition (CVD) is a process commonly used for the synthesis of thin films for several important technological applications, for example, microelectronics, hard coatings, and smart windows. Unfortunately, the complexity and prohibitive cost of CVD equipment makes it seldom available for undergraduate chemistry students. Here, a…

  8. Vapor spill pipe monitor

    DOEpatents

    Bianchini, G.M.; McRae, T.G.

    1983-06-23

    The invention is a method and apparatus for continually monitoring the composition of liquefied natural gas flowing from a spill pipe during a spill test by continually removing a sample of the LNG by means of a probe, gasifying the LNG in the probe, and sending the vaporized LNG to a remote ir gas detector for analysis. The probe comprises three spaced concentric tubes surrounded by a water jacket which communicates with a flow channel defined between the inner and middle, and middle and outer tubes. The inner tube is connected to a pump for providing suction, and the probe is positioned in the LNG flow below the spill pipe with the tip oriented partly downward so that LNG is continuously drawn into the inner tube through a small orifice. The probe is made of a high thermal conductivity metal. Hot water is flowed through the water jacket and through the flow channel between the three tubes to provide the necessary heat transfer to flash vaporize the LNG passing through the inner channel of the probe. The gasified LNG is transported through a connected hose or tubing extending from the probe to a remote ir sensor which measures the gas composition.

  9. Vapor spill pipe monitor

    NASA Astrophysics Data System (ADS)

    Bianchini, G. M.; McRae, T. G.

    1983-06-01

    The invention is a method and apparatus for continually monitoring the composition of liquefied natural gas flowing from a spill pipe during a spill test by continually removing a sample of the LNG by means of a probe, gasifying the LNG in the probe, and sending the vaporized LNG to a remote IR gas detector for analysis. The probe comprises three spaced concentric tubes surrounded by a water jacket which communicates with a flow channel defined between the inner and middle, and middle and outer tubes. The inner tube is connected to a pump for providing suction, and the probe is positioned in the LNG flow below the spill pipe with the tip oriented partly downward so that LNG is continuously drawn into the inner tube through a small orifice. The probe is made of a high thermal conductivity metal. Hot water is flowed through the water jacket and through the flow channel between the three tubes to provide the necessary heat transfer to flash vaporize the LNG passing through the inner channel of the probe. The gasified LNG is transported through a connected hose or tubing extending from the probe to a remote IR sensor which measures the gas composition.

  10. Vaporization Would Cool Primary Battery

    NASA Technical Reports Server (NTRS)

    Bhandari, Pradeep; Miyake, Robert N.

    1991-01-01

    Temperature of discharging high-power-density primary battery maintained below specified level by evaporation of suitable liquid from jacket surrounding battery, according to proposal. Pressure-relief valve regulates pressure and boiling temperature of liquid. Less material needed in cooling by vaporization than in cooling by melting. Technique used to cool batteries in situations in which engineering constraints on volume, mass, and location prevent attachment of cooling fins, heat pipes, or like.

  11. Chemical vapor deposition of sialon

    DOEpatents

    Landingham, R.L.; Casey, A.W.

    A laminated composite and a method for forming the composite by chemical vapor deposition are described. The composite includes a layer of sialon and a material to which the layer is bonded. The method includes the steps of exposing a surface of the material to an ammonia containing atmosphere; heating the surface to at least about 1200/sup 0/C; and impinging a gas containing N/sub 2/, SiCl/sub 4/, and AlCl/sub 3/ on the surface.

  12. THERMALLY OPERATED VAPOR VALVE

    DOEpatents

    Dorward, J.G. Jr.

    1959-02-10

    A valve is presented for use in a calutron to supply and control the vapor to be ionized. The invention provides a means readily operable from the exterior of the vacuum tank of the apparatuss without mechanical transmission of forces for the quick and accurate control of the ionizing arc by a corresponding control of gas flow theretos thereby producing an effective way of carefully regulating the operation of the calutron. The invention consists essentially of a tube member extending into the charge bottle of a calutron devices having a poppet type valve closing the lower end of the tube. An electrical heating means is provided in the valve stem to thermally vary the length of the stem to regulate the valve opening to control the flow of material from the charge bottle.

  13. Solar heat gain coefficient of complex fenestrations with a venetian blind for differing slat tilt angles

    SciTech Connect

    Klems, J.H.; Warner, J.L.

    1996-08-01

    Measured bidirectional transmittances and reflectances of a buff-colored venetian blind together with a layer calculation scheme developed in previous publications are utilized to produce directional-hemispherical properties for the venetian blind layer and solar heat gain coefficients for the blind in combination with clear double glazing. Results are presented for three blind slat tilt angles and for the blind mounted either interior to the double glazing or between the glass panes. Implications of the results for solar heat gain calculations are discussed in the context of sun positions for St. Louis, MO.

  14. Heat stress induces an aggregation of the light-harvesting complex of photosystem II in spinach plants.

    PubMed

    Tang, Yunlai; Wen, Xiaogang; Lu, Qingtao; Yang, Zhipan; Cheng, Zhukuan; Lu, Congming

    2007-02-01

    Whole spinach (Spinacia oleracea) plants were subjected to heat stress (25 degrees C-50 degrees C) in the dark for 30 min. At temperatures higher than 35 degrees C, CO2 assimilation rate decreased significantly. The maximal efficiency of photosystem II (PSII) photochemistry remained unchanged until 45 degrees C and decreased only slightly at 50 degrees C. Nonphotochemical quenching increased significantly either in the absence or presence of dithiothreitol. There was an appearance of the characteristic band at around 698 nm in 77 K fluorescence emission spectra of leaves. Native green gel of thylakoid membranes isolated immediately from heat-stressed leaves showed that many pigment-protein complexes remained aggregated in the stacking gel. The analyses of sodium dodecyl sulfate-polyacrylamide gel electrophoresis and immunoblotting demonstrated that the aggregates were composed of the main light-harvesting complex of PSII (LHCIIb). To characterize the aggregates, isolated PSII core complexes were incubated at 25 degrees C to 50 degrees C in the dark for 10 min. At temperatures over 35 degrees C, many pigment-protein complexes remained aggregated in the stacking gel of native green gel, and immunoblotting analyses showed that the aggregates were composed of LHCIIb. In addition, isolated LHCII was also incubated at 25 degrees C to 50 degrees C in the dark for 10 min. LHCII remained aggregated in the stacking gel of native green gel at temperatures over 35 degrees C. Massive aggregation of LHCII was clearly observed by using microscope images, which was accompanied by a significant increase in fluorescence quenching. There was a linear relationship between the formation of LHCII aggregates and nonphotochemical quenching in vivo. The results in this study suggest that LHCII aggregates may represent a protective mechanism to dissipate excess excitation energy in heat-stressed plants.

  15. A simple heated-capillary modification improves the analysis of non-covalent complexes by Z-spray electrospray ionization.

    PubMed

    Lippens, Jennifer L; Mangrum, J B; McIntyre, William; Redick, Bill; Fabris, D

    2016-03-30

    The observation of intact non-covalent complexes by electrospray ionization mass spectrometry (ESI-MS) hinges on the ability to minimize in-source activation processes that take place during analyte desolvation. We explored the merits of replacing the sampling cone of a standard Z-spray source with a heated capillary that makes the desolvation process slower and more gradual. We employed well-characterized protein-RNA, RNA-RNA, and DNA-DNA assemblies to compare the alternative configurations. Mass analysis evaluated the integrity of the complexes, whereas traveling wave ion mobility experiments assessed the stability of biomolecular structure. Analyses were performed back-to-back on the same samples on a Synapt G2 HDMS equipped with either the standard sampling cone or the heated-capillary apparatus. In each configuration, the source/capillary temperature was varied in controlled fashion, while keeping all other desolvation parameters constant to monitor the in-source dissociation of selected DNA duplexes. Ion mobility data were obtained from the same precursor by using the alternative configurations under the same settings. Monitoring the percentage of associated complex demonstrated that the heated capillary provided softer desolvation that was more conducive to the detection of intact non-covalent interactions. This configuration failed to produce complete dissociation of 14 bp and 24 bp duplexes, even when the source/capillary temperature was increased well above their solution melting points. Analyzed by IMS-MS, a selected construct displayed just one conformation with the heated capillary, but two with the standard sampling cone. The heated capillary minimizes in-source activation processes that can lead to unintended dissociation of complexes and perturbation of biomolecular structure, which rely on the integrity of non-covalent interactions. This effect can be attributed to the attenuation of the supersonic expansion typical of the Z-spray geometry and

  16. Rapid presumptive identification of the Mycobacterium tuberculosis-bovis complex by radiometric determination of heat stable urease

    SciTech Connect

    Gandy, J.H.; Pruden, E.L.; Cox, F.R.

    1983-12-01

    Simple and rapid Bactec methodologies for the determination of neat (unaltered) and heat stable urease activity of mycobacteria are presented. Clinical isolates (63) and stock cultures (32)--consisting of: M. tuberculosis (19), M. bovis (5), M. kansasii (15), M. marinum (4), M. simiae (3), M. scrofulaceum (16), M. gordonae (6), M. szulgai (6), M. flavescens (1), M. gastri (1), M. intracellulare (6), M. fortuitum-chelonei complex (12), and M. smegmatis (1)--were tested for neat urease activity by Bactec radiometry. Mycobacterial isolates (50-100 mg wet weight) were incubated at 35 degrees C for 30 minutes with microCi14C-urea. Urease-positive mycobacteria gave Bactec growth index (GI) values greater than 100 units, whereas urease-negative species gave values less than 10 GI units. Eighty-three isolates possessing neat urease activity were heated at 80 degrees C for 30 minutes followed by incubation at 35 degrees C for 30 minutes with 1 microCi14C-urea. Mycobacterium tuberculosis-bovis complex demonstrated heat-stable urease activity (GI more than 130 units) and could be distinguished from mycobacteria other than tuberculosis (MOTT), which gave GI values equal to or less than 40 units.

  17. Horizontal heat fluxes over complex terrain computed using a simple mixed-layer model and a numerical model

    SciTech Connect

    Kimura, Fujio; Kuwagata, Tuneo

    1995-02-01

    The thermally induced local circulation over a periodic valley is simulated by a two-dimensional numerical model that does-not include condensational processes. During the daytime of a clear, calm day, heat is transported from the mountainous region to the valley area by anabatic wind and its return flow. The specific humidity is, however, transported in an inverse manner. The horizontal exchange rate of sensible heat has a horizontal scale similarity, as long as the horizontal scale is less than a critical width of about 100 km. The sensible heat accumulated in an atmospheric column over an arbitrary point can be estimated by a simple model termed the uniform mixed-layer model (UML). The model assumes that the potential temperature is both vertically and horizontally uniform in the mixed layer, even over the complex terrain. The UML model is valid only when the horizontal scale of the topography is less than the critical width and the maximum difference in the elevation of the topography is less than about 1500 m. Latent heat is accumulated over the mountainous region while the atmosphere becomes dry over the valley area. When the horizontal scale is close to the critical width, the largest amount of humidity is accumulated during the late afternoon over the mountainous region. 18 refs., 15 figs., 1 tab.

  18. Thermal and hydraulic performance tests of a sieve-tray direct-contact heat exchanger vaporizing pure and mixed-hydrocarbon Rankine-cycle working fluids

    SciTech Connect

    Mines, G.L.; Demuth, O.J.; Wiggins, D.J.

    1983-08-01

    Experiments investigating a sieve-tray direct-contact heat exchanger were conducted at the Raft River Geothermal Test Site in southeastern Idaho using the 60-kW Mobile Heat Cycle Research Facility operating in the thermal loop mode (without a turbine). Isobutane, propane, and several hydrocarbon mixtures were heated and boiled in the direct-contact column, which is approx. 12 in. in diameter and 19-1/2 ft. high, using the energy from a 280/sup 0/F geothermal resource. Using pure fluids, isobutane or propane, the column operated much as intended, with 17 trays used for preheating and one or two accomplishing the boiling. For the pure fluids, individual tray efficiencies were found to be 70% or higher for preheating, and close to 100% for boiling; column pinch points were projected to be well under 1/sup 0/F with some runs reaching values as low as approx. 0.02/sup 0/F. Maximum geofluid throughputs for the isobutane tests corresponded roughly to the terminal rise velocity of a 1/32 in. working fluid droplet in geofluid. Boiling was found to occur in as many as 12 trays for the mixtures having the highest concentrations of the minor component, with overall efficiencies in the boiling section estimated on the order of 25 or 30%. Preheating tray efficiencies appeared to be fairly independent of working fluid, with pinch points ranging from as low as approx. 0.03/sup 0/F for a 0.95 isobutane/0.05 hexane mixture to approx. 2.3/sup 0/F for a 0.85 isobutane/0.05 hexane mixture. Column operation was noticeably less stable for the mixtures than for the pure fluids, with maximum throughputs dropping to as low as 40 to 50% of those for the pure fluids.

  19. The non-Newtonian heat and mass transport of He 2 in porous media used for vapor-liquid phase separation. Ph.D. Thesis

    NASA Technical Reports Server (NTRS)

    Yuan, S. W. K.

    1985-01-01

    This investigation of vapor-liquid phase separation (VLPS) of He 2 is related to long-term storage of cryogenic liquid. The VLPS system utilizes porous plugs in order to generate thermomechanical (thermo-osmotic) force which in turn prevents liquid from flowing out of the cryo-vessel (e.g., Infrared Astronomical Satellite). An apparatus was built and VLPS data were collected for a 2 and a 10 micrometer sintered stainless steel plug and a 5 to 15 micrometer sintered bronze plug. The VLPS data obtained at high temperature were in the nonlinear turbulent regime. At low temperature, the Stokes regime was approached. A turbulent flow model was developed, which provides a phenomenological description of the VLPS data. According to the model, most of the phase separation data are in the turbulent regime. The model is based on concepts of the Gorter-Mellink transport involving the mutual friction known from the zero net mass flow (ZNMF) studies. The latter had to be modified to obtain agreement with the present experimental VLPS evidence. In contrast to the well-known ZNMF mode, the VLPS results require a geometry dependent constant (Gorter-Mellink constant). A theoretical interpretation of the phenomenological equation for the VLPS data obtained, is based on modelling of the dynamics of quantized vortices proposed by Vinen. In extending Vinen's model to the VLPS transport of He 2 in porous media, a correlation between the K*(GM) and K(p) was obtained which permits an interpretation of the present findings. As K(p) is crucial, various methods were introduced to measure the permeability of the porous media at low temperatures. Good agreement was found between the room temperature and the low temperature K(p)-value of the plugs.

  20. Impact Welding of Aluminum to Copper and Stainless Steel by Vaporizing Foil Actuator: Effect of Heat Treatment Cycles on Mechanical Properties and Microstructure

    NASA Astrophysics Data System (ADS)

    Vivek, Anupam; Hansen, Steven; Benzing, Jake; He, Mei; Daehn, Glenn

    2015-10-01

    This work studies the mechanical property effect of microstructure on impact welds of aluminum alloy AA6061 with both copper alloy Cu 110 and stainless steel AISI 304. AA6061-T6 and T4 temper aluminum sheets of 1 mm thickness were launched toward copper and stainless steel targets using the vaporizing foil actuator technique. Flyer plate velocities, measured via photonic Doppler velocimetry, were observed to be approximately 800 m/s. The welded aluminum-copper samples were subjected to instrumented peel testing, microhardness testing, energy-dispersive X-ray spectroscopy, and scanning electron microscopy. The welded joints exhibited cracks through their continuous intermetallic layers. The cracks were impeded upon encountering a ductile metallic wave. The welds created with T6 temper flyer sheets were found to have smaller intermetallic-free and wavy interface regions as compared to those created with T4 temper flyer sheets. Peel strength tests of the two weld combinations resulted in failure along the interface in the case of the T6 flyer welds, while the failure generally occurred in the parent aluminum for the T4 temper flyer welds. Half of the T4 flyer welds were subjected to aging for 18 h at 433 K (160 °C) to convert the aluminum sheet to the T6 condition. Although the aged flyer material did not attain the hardness of the as-received T6 material, it was found to be significantly stronger than the T4 material. These welds retained their strength after the aging process, and diffusion across the interface was minimal. The welded aluminum-stainless steel samples were analyzed on a more basic level than aluminum-copper samples, but were found to exhibit similar results.

  1. Heat shock protein 70 kDa chaperone/DnaJ cochaperone complex employs an unusual dynamic interface.

    PubMed

    Ahmad, Atta; Bhattacharya, Akash; McDonald, Ramsay A; Cordes, Melissa; Ellington, Benjamin; Bertelsen, Eric B; Zuiderweg, Erik R P

    2011-11-22

    The heat shock protein 70 kDa (Hsp70)/DnaJ/nucleotide exchange factor system assists in intracellular protein (re)folding. Using solution NMR, we obtained a three-dimensional structure for a 75-kDa Hsp70-DnaJ complex in the ADP state, loaded with substrate peptide. We establish that the J domain (residues 1-70) binds with its positively charged helix II to a negatively charged loop in the Hsp70 nucleotide-binding domain. The complex shows an unusual "tethered" binding mode which is stoichiometric and saturable, but which has a dynamic interface. The complex represents part of a triple complex of Hsp70 and DnaJ both bound to substrate protein. Mutagenesis data indicate that the interface is also of relevance for the interaction of Hsp70 and DnaJ in the ATP state. The solution complex is completely different from a crystal structure of a disulfide-linked complex of homologous proteins [Jiang, et al. (2007) Mol Cell 28:422-433].

  2. Multicomponent fuel vaporization at high pressures.

    SciTech Connect

    Torres, D. J.; O'Rourke, P. J.

    2002-01-01

    We extend our multicomponent fuel model to high pressures using a Peng-Robinson equation of state, and implement the model into KIVA-3V. Phase equilibrium is achieved by equating liquid and vapor fugacities. The latent heat of vaporization and fuel enthalpies are also corrected for at high pressures. Numerical simulations of multicomponent evaporation are performed for single droplets for a diesel fuel surrogate at different pressures.

  3. Studies of oscillatory combustion and fuel vaporization

    NASA Technical Reports Server (NTRS)

    Borman, G. L.; Myers, P. S.; Uyehara, O. A.

    1972-01-01

    Research projects involving oscillatory combustion and fuel vaporization are reported. Comparisons of experimental and theoretical droplet vaporization histories under ambient conditions such that the droplet may approach its thermodynamic critical point are presented. Experimental data on instantaneous heat transfer from a gas to a solid surface under conditions of oscillatory pressure with comparisons to an unsteady one-dimensional model are analyzed. Droplet size and velocity distribution in a spray as obtained by use of a double flash fluorescent method were investigated.

  4. The vapor pressure of iron pentacarbonyl

    NASA Technical Reports Server (NTRS)

    Gilbert, A. G.; Sulzmann, K. G. P.

    1974-01-01

    Vapor pressure measurements have been made on pure iron pentacarbonyl between +31 and -19 C. The experimental results may be expressed by the logarithm of pressure (mm Hg) to the base 10 equals -(2096.7 K/T) + 8.4959, which corresponds to a heat of vaporization for the liquid carbonyl of delta H ? (9.588 plus or minus 0.12) kcal/mole. This result confirms and extends the earlier measurements made by Trautz and Badstuebner between 0 and 140 C. The need for careful purification of commercially available iron pentacarbonyl is emphasized, particularly for establishing the correct vapor pressure below 45 C.

  5. Vapor pressure and thermodynamics of actinide metals

    SciTech Connect

    Ward, J.W.; Kleinschmidt, P.D.; Haire, R.G.; Brown, D.

    1980-01-01

    Precise vapor pressure measurements by target collection/mass spectrometric Knudsen effusion techniques were combined with crystal entropy estimates to produce self-consistent free-enrgy functions, permitting calculation of heats, entropies and free energies from 298/sup 0/K to the highest temperatures of measurement. The vapor pressures and thermodyamics of vaporization of americium, curium, berkelium, and californium are compared in terms of electronic structure and bonding trends in the trans-plutonium elements. These resuslts are contrasted with the behavior of the early actinides, with attention to energy states and possible effects of f-electron bonding. 9 figures, 4 tables.

  6. Analytical framework for borehole heat exchanger (BHE) simulation influenced by horizontal groundwater flow and complex top boundary conditions

    NASA Astrophysics Data System (ADS)

    Rivera, Jaime; Blum, Philipp; Bayer, Peter

    2015-04-01

    Borehole heat exchangers (BHE) are the most widely used technologies for tapping low-enthalpy energy resources in the shallow subsurface. Analysis of these systems requires a proper simulation of the relevant processes controlling the transfer of heat between the BHE and the ground. Among the available simulation approaches, analytical methods are broadly accepted, especially when low computational costs and comprehensive analyses are demanded. Moreover, these methods constitute the benchmark solutions to evaluate the performance of more complex numerical models. Within the spectrum of existing (semi-)analytical models, those based on the superposition of problem-specific Green's functions are particularly appealing. Green's functions can be derived, for instance, for nodal or line sources with constant or transient strengths. In the same manner, functional forms can be obtained for scenarios with complex top boundary conditions whose temperature may vary in space and time. Other relevant processes, such as advective heat transport, mechanical dispersion and heat transfer through the unsaturated zone could be incorporated as well. A keystone of the methodology is that individual solutions can be added up invoking the superposition principle. This leads to a flexible and robust framework for studying the interaction of multiple processes on thermal plumes of BHEs. In this contribution, we present a new analytical framework and its verification via comparison with a numerical model. It simulates a BHE as a line source, and it integrates both horizontal groundwater flow and the effect of top boundary effects due to variable land use. All these effects may be implemented as spatially and temporally variable. For validation, the analytical framework is successfully applied to study cases where highly resolved temperature data is available.

  7. The microdetermination of H 2O, CO 2, and SO 2 in glass using a 1280°C microscope vacuum heating stage, cryopumping, and vapor pressure measurements from 77 to 273 K

    NASA Astrophysics Data System (ADS)

    Harris, David M.

    1981-11-01

    A new microscope vacuum heating stage and gas analyzer has been developed for measurement of H 2O, CO 2, SO 2, and noncondensable gas (H 2, CO, N 2, Ar, CH 4, etc.) evolved from samples, particularly natural glass, at temperatures up to 1280°C. The gas evolved upon heating to 1280δC is collected in a liquid nitrogen cold trap. Gas components are identified by the characteristic vapor pressure and temperature ranges over which solid and vapor are in equilibrium during sublimation of individual components. The masses of CO 2, SO 2, and H 2O derived from samples and blanks are calculated using the ideal gas law, the molecular weights of the components, and the gauge constant (i.e. the ratio of the number of moles of a gas to its partial pressure in the constant volume). Results obtained by repeated determinations of H 2O, CO 2, and SO 2 evolved from a submarine basaltic glass from Kilauea volcano, Hawaii, (average sample mass = 3 × 10 -3 g) gave probable errors for the determinations of H 2O (0.23%), CO 2 (0.025%), and S (0.071%) equal to 4, 10, and 8% respectively, of the concentrations. Determinations of H 2O in smaller samples of H 2O-poor basaltic pumice show a linear proportionality (0.063%) between the measured H 2O and the sample mass over the range 0.1 × 10 -6 to 1.7 × 10 -6 g H 2O. Comparisons of H 2O determinations by this technique with those obtained by Penfield, gas chromatic, microcoulometric, and vacuum fusion techniques used elsewhere show reasonably good agreement. Determinations of SO 2 by this technique agree reasonably well X-ray fluorescence and electron microprobe determinations of sulfur. Determinations of CO 2 by the present technique are reproducible but cannot be compared directly to measurements made in other labs because of differences in samples analyzed. The principle advantages of this analytical technique are the very small sample required, the simultaneous determination of H 2O, CO 2, SO 2 and noncondensable gas, the avoidance of

  8. A simple heated-capillary modification improves the analysis of non-covalent complexes by Z-spray electrospray ionization

    PubMed Central

    Lippens, Jennifer L; Mangrum, J.B.; McIntyre, William; Redick, Bill; Fabris, D.

    2016-01-01

    Rationale The observation of intact non-covalent complexes by ESI-MS hinges on the ability to minimize in-source activation processes that take place during analyte desolvation. We explored the merits of replacing the sampling cone of a standard Z-spray source with a heated capillary that makes the desolvation process slower and more gradual. We employed well-characterized protein-RNA and DNA-DNA assemblies to compare the alternative configurations. Methods Mass analysis evaluated the complexes’ integrity, whereas traveling wave ion mobility experiments assessed the stability of biomolecular structure. Analyses were performed back-to-back on the same samples on a Synapt G2 HDMS equipped with either the standard sampling cone or the heated-capillary apparatus. In each configuration, the source/capillary temperature was varied in controlled fashion, while keeping all other desolvation parameters constant to monitor the in-source dissociation of selected DNA duplexes. Ion mobility data were obtained from the same precursor by using the alternative configurations under the same settings. Results Monitoring the percentage of associated complex demonstrated that the heated capillary provided softer desolvation that was more conducive to the detection of intact non-covalent interactions. This configuration failed to produce complete dissociation of 14bp and 24bp duplexes, even when the source/capillary temperature was increased well above their solution melting points. Analyzed by IMS-MS, a selected construct displayed just one conformation with the heated capillary, but two with the standard sampling cone. Conclusions The heated capillary minimizes in-source activation processes that can lead to unintended dissociation of complexes and perturbation of biomolecular structure, which rely on the integrity of non-covalent interactions. This effect can be attributed to the attenuation of the supersonic expansion typical of the Z-spray geometry and the greater ability to

  9. Metal vapor laser including hot electrodes and integral wick

    DOEpatents

    Ault, E.R.; Alger, T.W.

    1995-03-07

    A metal vapor laser, specifically one utilizing copper vapor, is disclosed herein. This laser utilizes a plasma tube assembly including a thermally insulated plasma tube containing a specific metal, e.g., copper, and a buffer gas therein. The laser also utilizes means including hot electrodes located at opposite ends of the plasma tube for electrically exciting the metal vapor and heating its interior to a sufficiently high temperature to cause the metal contained therein to vaporize and for subjecting the vapor to an electrical discharge excitation in order to lase. The laser also utilizes external wicking arrangements, that is, wicking arrangements located outside the plasma tube. 5 figs.

  10. Metal vapor laser including hot electrodes and integral wick

    DOEpatents

    Ault, Earl R.; Alger, Terry W.

    1995-01-01

    A metal vapor laser, specifically one utilizing copper vapor, is disclosed herein. This laser utilizes a plasma tube assembly including a thermally insulated plasma tube containing a specific metal, e.g., copper, and a buffer gas therein. The laser also utilizes means including hot electrodes located at opposite ends of the plasma tube for electrically exciting the metal vapor and heating its interior to a sufficiently high temperature to cause the metal contained therein to vaporize and for subjecting the vapor to an electrical discharge excitation in order to lase. The laser also utilizes external wicking arrangements, that is, wicking arrangements located outside the plasma tube.

  11. Pumped two-phase heat transfer loop

    NASA Technical Reports Server (NTRS)

    Edelstein, Fred

    1988-01-01

    A pumped loop two-phase heat transfer system, operating at a nearly constant temperature throughout, includes several independently operating grooved capillary heat exchanger plates supplied with working fluid through independent flow modulation valves connected to a liquid supply line, a vapor line for collecting vapor from the heat exchangers, a condenser between the vapor and the liquid lines, and a fluid circulating pump between the condenser and the heat exchangers.

  12. Pumped two-phase heat transfer loop

    NASA Technical Reports Server (NTRS)

    Edelstein, Fred (Inventor)

    1987-01-01

    A pumped loop two-phase heat transfer system, operating at a nearly constant temperature throughout, includes a plurality of independently operating grooved capillary heat exchanger plates supplied with working fluid through independent flow modulation valves connected to a liquid supply line, a vapor line for collecting vapor from the heat exchangers, a condenser between the vapor and the liquid lines, and a fluid circulating pump between the condenser and the heat exchangers.

  13. Optimization of metal vapor lasers

    NASA Astrophysics Data System (ADS)

    Buchanov, V. V.; Molodykh, E. I.; Tykotskii, V. V.

    1983-03-01

    The method proposed here for performing numerical calculations on a computer in order to predict and optimize the characteristics of metal vapor lasers is based on the use of a universal program for numerical experiments designed expressly for metal vapor lasers and on a simultaneous application of an algorithm for multifactor optimization of the output parameters. The latter, in turn, is based on the complex Boks method (Himmelblau, 1970) and on the Gel'fand-Tsetlin ravine method (Himmelblau, 1970). Calculations carried out for a metal with a copper vapor in neon reveal that for optimization with respect to the geometry of the active zone and the parameters of the electrical circuits (including the voltage pulses and excitation frequency) it is sufficient to use the Boks method. The objective function optimum regarding the concentration of the metal particles and the buffer gas found using this algorithm calls for further refinement; this can be performed efficiently with the Gel'fand-Tsetlin ravine method.

  14. A method for optimum heating and cooling boiler components of a complex shape

    NASA Astrophysics Data System (ADS)

    Duda, Piotr; Rząsa, Dariusz

    2015-06-01

    A numerical method for determining a transient fluid temperature is presented. The method is formulated to minimizethe total time of heating and cooling operation based on the assumption that maximum tensile and compressivetotal stresses in a solid can not exceed the allowable value during the entire process. The method can be used for any construction element of a simple or complicated geometry. In this method, material properties of solids can be assumed as constant or temperature dependent. The method will be implemented for the heating operationof an outlet header. This construction element is mounted in supercritical power plants. The outlet header is installed in the 460 MW power unit and it is designed for the working pressure of p w = 26.5 MPa and the steam working temperature of T w = 554°C. The results obtained from the proposed method will be compared with the calculations according to TRD 301 - German boiler code

  15. Enhancing oxidative stability in heated oils using core/shell structures of collagen and α-tocopherol complex.

    PubMed

    Gim, Seo Yeong; Hong, Seungmi; Kim, Jisu; Kwon, YongJun; Kim, Mi-Ja; Kim, GeunHyung; Lee, JaeHwan

    2017-11-15

    In this study, collagen mesh structure was prepared by carrying α-tocopherol in the form of core/shell complex. Antioxidant properties of α-tocopherol loaded carriers were tested in moisture added bulk oils at 140°C. From one gram of collagen core/shell complex, 138mg α-tocopherol was released in medium chain triacylglycerol (MCT). α-Tocopherol was substantially protected against heat treatment when α-tocopherol was complexed in collagen core/shell. Oxidative stability in bulk oil was significantly enhanced by added collagen mesh structure or collagen core/shell complex with α-tocopherol compared to that in control bulk oils (p<0.05), although no significant difference was observed between oils containing collagen mesh structure and collagen core/shell with α-tocopherol (p>0.05). Results of DPPH loss in methanol demonstrated that collagen core/shell with α-tocopherol had significantly (p<0.05) higher antioxidant properties than collagen mesh structure up to a certain period. Therefore, collagen core/shell complex is a promising way to enhance the stability of α-tocopherol and oxidative stability in oil-rich foods prepared at high temperature. Copyright © 2017 Elsevier Ltd. All rights reserved.

  16. Effect of water vapors on the luminescence of cation-exchange membranes modified by Pt(II) and Ru(II) complexes and Nile blue

    NASA Astrophysics Data System (ADS)

    Khakhalina, M. S.; Musaeva, D. N.; Tikhomirova, I. Yu.; Puzyk, M. V.

    2010-04-01

    The surface of a cation-exchange membrane was modified by the [PtEnPpy]+, [PtEnBt]+, [PtEnTpy]+, [RuBpy3]+2, and NB+, (En is ethylenediamine; Ppy, Bt, Tpy are α-deprotonated forms of 2-phenylpyridine, 2-phenylbenzothiazole, and 2-(2'-thienyl)pyridine, respectively; Bpy is 2,2'-bipyridyl, and NB+ is Nile blue) ions, which exhibit intense luminescence. It is found that the quenching of the luminescence of the modified cation-exchange membrane by water vapors depends on the nature of the excited electronic state of the immobilized cation.

  17. Heat Pipe With Interrupted Slot

    NASA Technical Reports Server (NTRS)

    Brown, Richard F.; Kosson, Robert L.; Edelstein, Fred

    1994-01-01

    Newer version of heat pipe slot interrupted by plug or, if heat pipe is cast, by bridge of heat-pipe material cast integrally across groove. Small barrier assists in priming heat pipe. Vapor and noncondensible gas still accumulates in liquid channel at evaporator before or during startup, but barrier keeps liquid out of small part of slot at bubble. Dry part of slot allows bubble to escape into vapor channel, making room for liquid to move in during startup.

  18. Flat device for heat concentration or dispersion

    NASA Technical Reports Server (NTRS)

    Jenkins, R. V.; Sabol, A. P.

    1975-01-01

    Device provides low-cost unit for efficiently transferring heat between, either to or from, flat surface and central point or region. It is based upon vapor heat transfer principle and therefore, extends applicability of heat pipe.

  19. Fluid flow and heat transfer in polygonal micro heat pipes

    NASA Astrophysics Data System (ADS)

    Rao, Sai; Wong, Harris

    2015-11-01

    Micro heat pipes have been used to cool microelectronic devices, but their heat transfer coefficients are low compared with those of conventional heat pipes. We model heat and mass transfer in triangular, square, hexagonal, and rectangular micro heat pipes under small imposed temperature differences. A micro heat pipe is a closed microchannel filled with a wetting liquid and a long vapor bubble. When a temperature difference is applied across a micro heat pipe, the equilibrium vapor pressure at the hot end is higher than that at the cold end, and the difference drives a vapor flow. As the vapor moves, the vapor pressure at the hot end drops below the saturation pressure. This pressure drop induces continuous evaporation from the interface. Two dimensionless numbers emerge from the momentum and energy equations: the heat-pipe number H, and the evaporation exponent S. When H >> 1 and S >> 1, vapor-flow heat transfer dominates and a thermal boundary layer appears at the hot end, the thickness of which scales as L/S, where L is the half-length of the pipe. A similar boundary layer exists at the cold end. Outside the boundary layers, the temperature is uniform. We also find a dimensionless optimal pipe length Sm =Sm(H) for maximum evaporative heat transfer. Thus, our model suggests that micro heat pipes should be designed with H >> 1 and S =Sm. We calculate H and S for four published micro-heat-pipe experiments, and find encouraging support for our design criterion.

  20. Heat Transfer in a Complex Trailing Edge Passage for a High Pressure Turbine Blade. Part 2:; Simulation Results

    NASA Technical Reports Server (NTRS)

    Rigby, David L.; Bunker, Ronald S.

    2002-01-01

    A combined experimental and numerical study to investigate the heat transfer distribution in a complex blade trailing edge passage was conducted. The geometry consists of a two pass serpentine passage with taper toward the trailing edge, as well as from hub to tip. The upflow channel has an average aspect ratio of roughly 14:1, while the exit passage aspect ratio is about 5:1. The upflow channel is split in an interrupted way and is smooth on the trailing edge side of the split and turbulated on the other side. A turning vane is placed near the tip of the upflow channel. Reynolds numbers in the range of 31,000 to 61,000, based on inlet conditions, were simulated numerically. The simulation was performed using the Glenn-HT code, a full three-dimensional Navier-Stokes solver using the Wilcox k-omega turbulence model. A structured multi-block grid is used with approximately 4.5 million cells and average y+ values on the order of unity. Pressure and heat transfer distributions are presented with comparison to the experimental data. While there are some regions with discrepancies, in general the agreement is very good for both pressure and heat transfer.

  1. Enhanced vacuum arc vapor deposition electrode

    NASA Technical Reports Server (NTRS)

    Weeks, Jack L. (Inventor); Todd, Douglas M. (Inventor)

    1999-01-01

    A process for forming a thin metal coating on a substrate wherein a gas stream heated by an electrical current impinges on a metallic target in a vacuum chamber to form a molten pool of the metal and then vaporize a portion of the pool, with the source of the heated gas stream being on one side of the target and the substrate being on the other side of the target such that most of the metallic vapor from the target is directed at the substrate.

  2. Boron and Zirconium from Crucible Refractories in a Complex Heat-Resistant Alloy

    NASA Technical Reports Server (NTRS)

    Decker, R F; Rowe, John P; Freeman, J W

    1958-01-01

    In a laboratory study of the factors involved in the influence of induction vacuum melting on 55ni-20cr-15co-4mo-3ti-3al heat resistant alloy, it was found that the major factor was the type of ceramic used as the crucible. The study concluded that trace amounts of boron or zirconium derived from reaction of the melt with the crucible refactories improved creep-rupture properties at 1,600 degrees F. Boron was most effective and, in addition, markedly improved hot-workability.

  3. The Experimental Measurement of Aerodynamic Heating About Complex Shapes at Supersonic Mach Numbers

    NASA Technical Reports Server (NTRS)

    Neumann, Richard D.; Freeman, Delma C.

    2011-01-01

    In 2008 a wind tunnel test program was implemented to update the experimental data available for predicting protuberance heating at supersonic Mach numbers. For this test the Langley Unitary Wind Tunnel was also used. The significant differences for this current test were the advances in the state-of-the-art in model design, fabrication techniques, instrumentation and data acquisition capabilities. This current paper provides a focused discussion of the results of an in depth analysis of unique measurements of recovery temperature obtained during the test.

  4. Modeling the heat transfer in geometrically complex media with a volume source

    SciTech Connect

    Gurevich, M. I. Tel’kovskaya, O. V.; Chukbar, B. K.; Shkarovskiy, D. A.

    2014-12-15

    Fuel elements produced from spent fuel are porous media with spatially varying characteristics. A hierarchical discrete structure for the numerical modeling of heat-transfer processes in media with an anisotropic geometry that is characterized by both the microscopic voids and macroscopic changes in the parameters is proposed. The basic unit of the structure at its lower level is a cell that represents the local properties of the medium. The cells have a standard interface that allows one to form three-dimensional networks of such cells. Different types of cells in the network represent macroscopic changes. The potential for parallel processing is analyzed.

  5. Vapor intrusion from entrapped NAPL sources and groundwater plumes

    NASA Astrophysics Data System (ADS)

    Illangasekare, Tissa H.; Sakaki, Toshihiro; Christ, John; Petri, Bejamin; Sauck, Carolyn; Cihan, Abdullah

    2010-05-01

    Volatile organic compounds (VOC) are commonly found entrapped as non-aqueous phase liquids (NAPLs) in the soil pores or dissolved in groundwater at industrial waste sites and refineries. Vapors emitted from these contaminant sources readily disperse into the atmosphere, into air-filled void spaces within the soil, and migrate below surface structures, leading to the intrusion of contaminant vapors into indoor air through basements and other underground structures. This process referred to as vapor intrusion (VI) represents a potential threat to human health, and is a possible exposure pathway of concern to regulatory agencies. To assess whether this exposure pathway is present, remediation project managers often rely in part on highly simplified screening level models that do not take into consideration the complex flow dynamics controlled by subsurface heterogeneities and soil moisture conditions affected by the mass and heat flux boundary conditions at the land/atmospheric interface. A research study is under way to obtain an improved understanding of the processes and mechanisms controlling vapor generation from entrapped NAPL sources and groundwater plumes, their subsequent migration through the subsurface, and their attenuation in naturally heterogeneous vadose zones under various natural physical, climatic, and geochemical conditions. Experiments conducted at multiple scales will be integrated with analytical and numerical modeling and field data to test and validate existing VI theories and models. A set of preliminary experiments where the fundamental process of vapor generation from entrapped NAPL sources and dissolved plumes under fluctuating water were investigated in small cells and two-dimensional test tanks. In another task, intermediate scale experiments were conducted to generate quantitative data on how the heat and mass flux boundary conditions control the development of dynamic VI pathways. The data from the small cell and tank experiments were

  6. Induction of a heat-stable topoisomerase II-DNA cleavable complex by nonintercalative terpenoides, terpentecin and clerocidin.

    PubMed

    Kawada, S; Yamashita, Y; Fujii, N; Nakano, H

    1991-06-01

    Terpentecin and clerocidin, microbial terpenoides, have been known to be potent antitumor antibiotics. However, the critical biochemical target of these terpenoides has not been identified. Our present studies, using purified mammalian topoisomerase II, have shown that terpentecin and clerocidin induce topoisomerase II-mediated DNA cleavage in vitro with comparable potency to that of demethylepipodophyllotoxin ethylidene-beta-D-glucoside. These terpenoides produced a similar DNA cleavage pattern which is distinctly different from those generated in the presence of the known topoisomerase poisons, demethylepipodophyllotoxin ethylidene-beta-D-glucoside and 4'-(9-acridinylamino)methanesulfon-m-anisidide. Brief heating at 65 degrees C, which abolishes completely the cleavable complex with demethylepipodophyllotoxin ethylidene-beta-D-glucoside, of the reaction mixture containing these terpenoides resulted in slight reduction in DNA cleavage. Thus, differently from other topoisomerase II-active antitumor agents, terpentecin and clerocidin induce formation of a cleavable complex which is stable for heat or salt treatments. The lack of significant DNA binding or intercalation activity of terpentecin and clerocidin suggests that topoisomerase II is a cellular target for these drugs.

  7. Heteromeric complexes of heat shock protein 70 (HSP70) family members, including Hsp70B′, in differentiated human neuronal cells

    PubMed Central

    Chow, Ari M.; Mok, Philip; Xiao, Dawn; Khalouei, Sam

    2010-01-01

    Human neurodegenerative disorders such as Alzheimer’s disease, Parkinson’s disease, and amyotrophic lateral sclerosis have been termed “protein misfolding disorders.” Upregulation of heat shock proteins that target misfolded aggregation-prone proteins has been proposed as a potential therapeutic strategy to counter neurodegenerative disorders. The heat shock protein 70 (HSP70) family is well characterized for its cytoprotective effects against cell death and has been implicated in neuroprotection by overexpression studies. HSP70 family members exhibit sequence and structural conservation. The significance of the multiplicity of HSP70 proteins is unknown. In this study, coimmunoprecipitation was employed to determine if association of HSP70 family members occurs, including Hsp70B′ which is present in the human genome but not in mouse and rat. Heteromeric complexes of Hsp70B′, Hsp70, and Hsc70 were detected in differentiated human SH-SY5Y neuronal cells. Hsp70B′ also formed complexes with Hsp40 suggesting a common co-chaperone for HSP70 family members. PMID:20084477

  8. LOX vaporization in high-pressure, hydrogen-rich gas

    NASA Technical Reports Server (NTRS)

    Litchford, Ron J.; Jeng, San-Mou

    1990-01-01

    LOX droplet vaporization in high-pressure hydrogen-rich gas is analyzed, with special attention to thermodynamic effects which compel the surface to heat to the critical state and to supercritical vaporization processes on heating to criticality. Subcritical vaporization is modeled using a quasi-steady diffusion-controlled gas-phase transport formulation coupled to an effective-conductivity internal-energy-transport model accounting for circulation effects. It is demonstrated how the droplet surface might heat to the critical state, for ambient pressures slightly greater than the critical pressure of oxygen, such that the bulk of propellant within the droplet remains substantially below the critical mixing temperature.

  9. Role of the heat-induced whey protein/kappa-casein complexes in the formation of acid milk gels: a kinetic study using rheology and confocal microscopy.

    PubMed

    Guyomarc'h, Fanny; Jemin, Marlène; Le Tilly, Véronique; Madec, Marie-Noëlle; Famelart, Marie-Hélène

    2009-07-08

    The effect of heat treatment of milk on the formation of acid gel was examined using confocal scanning laser microscopy and low-amplitude dynamic oscillation throughout acidification. Milk samples were reconstituted by mixing colloidal phase from unheated or preheated skim milk, labeled with rhodamine B isothiocyanate, with the aqueous phase from unheated or preheated milk, labeled with fluorescein isothiocyanate. Gels were made by acidification with glucono-delta-lactone. The presence of material from preheated milk, that is, either the colloidal or the aqueous phase or both, led to an increase in the gelation pH and in the final elastic modulus and to a more branched network with larger pores. During acidification, the heat-induced serum complexes and the casein micelles did not appear to form separated gels with time or in space. Moreover, the colocalization in the final network of serum heat-induced complexes and casein micelles is particularly well observed in the presence of an aqueous phase obtained from preheated milk. Finally, because the rheological and microstructural properties of acid gels containing either micelle-bound or serum heat-induced complexes were similar, it was suggested that the serum heat-induced complexes interacted with the casein micelles early in the course of acidification and that formation of the network did not differ significantly whether the heat-induced complexes were initially found in the aqueous phase of milk or bound to casein micelles.

  10. Thermoregulation in complex situations: combined heat exposure, infectious fever and water deprivation

    NASA Astrophysics Data System (ADS)

    Blatteis, C. M.

    Heat exposure, infectious fever and water deprivation are stressors that, individually, produce disturbances in more than one regulated system, calling for diverse compensatory responses. A potential conflict is created when these stimuli are combined and impose concurrent stressful loads on the body because the homeostatic defenses mobilized against one are also partly needed against the other stressors. To learn how the competing demands of combined stressors for shared regulatory systems are met, rabbits were exposed to 32°C and 37°C (heat), administered lipopolysaccharide (Salmonella enteritidis LPS, 2 µg/kg, i.v.) in temperatures of 22°C or 27°C, or water-deprived for 1 or 2 days in 22°C or 27°C, in separate experiments. The corresponding controls were exposed to 22°C or 27°C, administered pyrogen-free saline i.v. in 22°C or 27°C, or normally hydrated in 22°C or 27°C. In subsequent experiments, two or all three of these treatments were applied concurrently. Core and ear skin temperatures and respiratory rates were monitored continuously. The results indicated that the concomitant needs of moderate heat exposure, fever and 1 day of water deprivation were generally met by the regulatory systems involved, but different patterns of thermoeffector activities were evoked and the eventual body temperature changes produced were different under each condition. However, when the test conditions were severe, their combined needs were not met adequately and the eventual compensatory response depended not only on the particular stimulus intensity, but also on the immediate importance for survival of the functions being defended. Thus, dehydration was the most dangerous factor to the physiological integrity of the animals. In sum, conflicting physiological stimuli appear to result in responses that are different from the responses to a single perturbation, the eventual output representing the resultant of the inputs rather than a singular output dictated by one

  11. Vaporization chambers and associated methods

    DOEpatents

    Turner, Terry D.; Wilding, Bruce M.; McKellar, Michael G.; Shunn, Lee P.

    2017-02-21

    A vaporization chamber may include at least one conduit and a shell. The at least one conduit may have an inlet at a first end, an outlet at a second end and a flow path therebetween. The shell may surround a portion of each conduit and define a chamber surrounding the portion of each conduit. Additionally, a plurality of discrete apertures may be positioned at longitudinal intervals in a wall of each conduit, each discrete aperture of the plurality of discrete apertures sized and configured to direct a jet of fluid into each conduit from the chamber. A liquid may be vaporized by directing a first fluid comprising a liquid into the inlet at the first end of each conduit, directing jets of a second fluid into each conduit from the chamber through discrete apertures in a wall of each conduit and transferring heat from the second fluid to the first fluid.

  12. Enthalpy By Energy Balance for Aerodynamic Heating Facility at NASA Ames Research Center Arc Jet Complex

    NASA Technical Reports Server (NTRS)

    Hightower, T. Mark; MacDonald, Christine L.; Martinez, Edward R.; Balboni, John A.; Anderson, Karl F.; Arnold, Jim O. (Technical Monitor)

    2002-01-01

    The NASA Ames Research Center (ARC) Arc Jet Facilities' Aerodynamic Heating Facility (AHF) has been instrumented for the Enthalpy By Energy Balance (EB2) method. Diagnostic EB2 data is routinely taken for all AHF runs. This paper provides an overview of the EB2 method implemented in the AHF. The chief advantage of the AHF implementation over earlier versions is the non-intrusiveness of the instruments used. For example, to measure the change in cooling water temperature, thin film 1000 ohm Resistance Temperature Detectors (RTDs) are used with an Anderson Current Loop (ACL) as the signal conditioner. The ACL with 1000 ohm RTDs allows for very sensitive measurement of the increase in temperature (Delta T) of the cooling water to the arc heater, which is a critical element of the EB2 method. Cooling water flow rates are measured with non-intrusive ultrasonic flow meters.

  13. On the vertical exchange of heat, mass and momentum over complex, mountainous terrain

    NASA Astrophysics Data System (ADS)

    Rotach, Mathias; Gohm, Alexander; Lang, Moritz; Leukauf, Daniel; Stiperski, Ivana; Wagner, Johannes

    2015-12-01

    The role of the atmospheric boundary layer (ABL) in the atmosphere-climate system is the exchange of heat, mass and momentum between 'the earth's surface' and the atmosphere. Traditionally, it is understood that turbulent transport is responsible for this exchange and hence the understanding and physical description of the turbulence structure of the boundary layer is key to assess the effectiveness of earth-atmosphere exchange. This understanding is rooted in the (implicit) assumption of a scale separation or spectral gap between turbulence and mean atmospheric motions, which in turn leads to the assumption of a horizontally homogeneous and flat (HHF) surface as a reference, for which both physical understanding and model parameterizations have successfully been developed over the years. Over mountainous terrain, however, the ABL is generically inhomogeneous due to both thermal (radiative) and dynamic forcing. This inhomogeneity leads to meso-scale and even sub-meso-scale flows such as slope and valley winds or wake effects. It is argued here that these (sub)meso-scale motions can significantly contribute to the vertical structure of the boundary layer and hence vertical exchange of heat and mass between the surface and the atmosphere. If model grid resolution is not high enough the latter will have to be parameterized (in a similar fashion as gravity wave drag parameterizations take into account the momentum transport due to gravity waves in large-scale models). In this contribution we summarize the available evidence of the contribution of (sub)meso-scale motions to vertical exchange in mountainous terrain from observational and numerical modeling studies. In particular, a number of recent simulation studies using idealized topography will be summarized and put into perspective - so as to identify possible limitations and areas of necessary future research.

  14. Multiple source heat pump

    DOEpatents

    Ecker, Amir L.

    1983-01-01

    A heat pump apparatus for conditioning a fluid characterized by a fluid handler and path for circulating a fluid in heat exchange relationship with a refrigerant fluid, at least three refrigerant heat exchangers, one for effecting heat exchange with the fluid, a second for effecting heat exchange with a heat exchange fluid, and a third for effecting heat exchange with ambient air; a compressor for compressing the refrigerant; at least one throttling valve connected at the inlet side of a heat exchanger in which liquid refrigerant is vaporized; a refrigerant circuit; refrigerant; a source of heat exchange fluid; heat exchange fluid circuit and pump for circulating the heat exchange fluid in heat exchange relationship with the refrigerant; and valves or switches for selecting the heat exchangers and directional flow of refrigerant therethrough for selecting a particular mode of operation. Also disclosed are a variety of embodiments, modes of operation, and schematics therefor.

  15. External artery heat pipe

    NASA Technical Reports Server (NTRS)

    Gernert, Nelson J. (Inventor); Ernst, Donald M. (Inventor); Shaubach, Robert M. (Inventor)

    1989-01-01

    An improved heat pipe with an external artery. The longitudinal slot in the heat pipe wall which interconnects the heat pipe vapor space with the external artery is completely filled with sintered wick material and the wall of the external artery is also covered with sintered wick material. This added wick structure assures that the external artery will continue to feed liquid to the heat pipe evaporator even if a vapor bubble forms within and would otherwise block the liquid transport function of the external artery.

  16. High-Temperature Vaporization of Mg-Ca-Carbonate-Sulfate-Quartz-Alumina Targets

    NASA Astrophysics Data System (ADS)

    Dikov, Yu. P.; Gerasimov, M. V.; Yakovlev, O. I.; Wlotzka, F.

    1996-03-01

    In a series of experiments we studied the chemistry of high-temperature vaporization in the Ca-carbonate-sulfate-quartz system in relation to the Chicxulub impact. Since Mg-carbonates are a major constituent of the rocks in the Chicxulub crater area, it is important to study the evaporative chemistry of MgCO3 together with the cited system. We performed high-temperature vaporization of MgCO3 + CaCO3 + CaSO4/CaSO4 x 2H2O + SiO2 (in one experiment we used anhydrite and in another gypsum) targets using standard laser-pulse heating technique to simulate impact vaporization. In the third experimental run we added Al2O3 to simulate the alumo-silicate component of Chicxulub target rocks and to investigate the behavior of Al during vaporization. The results show a complex chemistry which occurs in the vapor cloud, resulting in (1) noticeable trapping of S, C, and of H2O by condensing products; (2) formation of Mg and Al sheet silicates in experiments with water-containing targets; and (3) strong reduction processes in experiments with water-containing targets.

  17. Stratospheric water vapor feedback.

    PubMed

    Dessler, A E; Schoeberl, M R; Wang, T; Davis, S M; Rosenlof, K H

    2013-11-05

    We show here that stratospheric water vapor variations play an important role in the evolution of our climate. This comes from analysis of observations showing that stratospheric water vapor increases with tropospheric temperature, implying the existence of a stratospheric water vapor feedback. We estimate the strength of this feedback in a chemistry-climate model to be +0.3 W/(m(2)⋅K), which would be a significant contributor to the overall climate sensitivity. One-third of this feedback comes from increases in water vapor entering the stratosphere through the tropical tropopause layer, with the rest coming from increases in water vapor entering through the extratropical tropopause.

  18. Vapor phase pyrolysis

    NASA Technical Reports Server (NTRS)

    Steurer, Wolfgang

    1992-01-01

    The vapor phase pyrolysis process is designed exclusively for the lunar production of oxygen. In this concept, granulated raw material (soil) that consists almost entirely of metal oxides is vaporized and the vapor is raised to a temperature where it dissociates into suboxides and free oxygen. Rapid cooling of the dissociated vapor to a discrete temperature causes condensation of the suboxides, while the oxygen remains essentially intact and can be collected downstream. The gas flow path and flow rate are maintained at an optimum level by control of the pressure differential between the vaporization region and the oxygen collection system with the aid of the environmental vacuum.

  19. Heat pump system

    DOEpatents

    Swenson, Paul F.; Moore, Paul B.

    1983-01-01

    An air heating and cooling system for a building includes an expansion type refrigeration circuit and a vapor power circuit. The refrigeration circuit includes two heat exchangers, one of which is communicated with a source of indoor air from the building and the other of which is communicated with a source of air from outside the building. The vapor power circuit includes two heat exchangers, one of which is disposed in series air flow relationship with the indoor refrigeration circuit heat exchanger and the other of which is disposed in series air flow relationship with the outdoor refrigeration circuit heat exchanger. Fans powered by electricity generated by a vapor power circuit alternator circulate indoor air through the two indoor heat exchangers and circulate outside air through the two outdoor heat exchangers. The system is assembled as a single roof top unit, with a vapor power generator and turbine and compressor thermally insulated from the heat exchangers, and with the indoor heat exchangers thermally insulated from the outdoor heat exchangers.

  20. Heat pump system

    DOEpatents

    Swenson, Paul F.; Moore, Paul B.

    1977-01-01

    An air heating and cooling system for a building includes an expansion type refrigeration circuit and a vapor power circuit. The refrigeration circuit includes two heat exchangers, one of which is communicated with a source of indoor air from the building and the other of which is communicated with a source of air from outside the building. The vapor power circuit includes two heat exchangers, one of which is disposed in series air flow relationship with the indoor refrigeration circuit heat exchanger and the other of which is disposed in series air flow relationship with the outdoor refrigeration circuit heat exchanger. Fans powered by electricity generated by a vapor power circuit alternator circulate indoor air through the two indoor heat exchangers and circulate outside air through the two outdoor heat exchangers. The system is assembled as a single roof top unit, with a vapor power generator and turbine and compressor thermally insulated from the heat exchangers, and with the indoor heat exchangers thermally insulated from the outdoor heat exchangers.

  1. Heat pump system

    DOEpatents

    Swenson, Paul F.; Moore, Paul B.

    1983-06-21

    An air heating and cooling system for a building includes an expansion type refrigeration circuit and a vapor power circuit. The refrigeration circuit includes two heat exchangers, one of which is communicated with a source of indoor air from the building and the other of which is communicated with a source of air from outside the building. The vapor power circuit includes two heat exchangers, one of which is disposed in series air flow relationship with the indoor refrigeration circuit heat exchanger and the other of which is disposed in series air flow relationship with the outdoor refrigeration circuit heat exchanger. Fans powered by electricity generated by a vapor power circuit alternator circulate indoor air through the two indoor heat exchangers and circulate outside air through the two outdoor heat exchangers. The system is assembled as a single roof top unit, with a vapor power generator and turbine and compressor thermally insulated from the heat exchangers, and with the indoor heat exchangers thermally insulated from the outdoor heat exchangers.

  2. Leidenfrost Vapor Layer Stabilization on Superhydrophobic Surfaces

    NASA Astrophysics Data System (ADS)

    Vakarelski, Ivan; Patankar, Neelesh; Marston, Jeremy; Chan, Derek; Thoroddsen, Sigurdur

    2012-11-01

    We have performed experiments to investigate the influence of the wettability of a superheated metallic sphere on the stability of a thin vapor layer during the cooling of a sphere immersed in water. For high enough sphere temperatures, a continuous vapor layer (Leidenfrost regime) is observed on the surface of non-superhydrophobic spheres, but below a critical sphere temperature the layer becomes unstable and explosively switches to nuclear boiling regime. In contrast, when the sphere surface is textured and superhydrophobic, the vapor layer is stable and gradually relaxes to the sphere surface until the complete cooling of the sphere, thus avoiding the nuclear boiling transition altogether. This finding could help in the development of heat exchange devices and of vapor layer based drag reducing technologies.

  3. Model for the Vaporization of Mixed Organometallic Compounds in the Metalorganic Chemical Vapor Deposition of High Temperature Superconducting Films

    NASA Technical Reports Server (NTRS)

    Meng, Guangyao; Zhou, Gang; Schneider, Roger L.; Sarma, Bimal K.; Levy, Moises

    1993-01-01

    A model of the vaporization and mass transport of mixed organometallics from a single source for thin film metalorganic chemical vapor deposition is presented. A stoichiometric gas phase can be obtained from a mixture of the organometallics in the desired mole ratios, in spite of differences in the volatilities of the individual compounds. Proper film composition and growth rates are obtained by controlling the velocity of a carriage containing the organometallics through the heating zone of a vaporizer.

  4. Monogroove liquid heat exchanger

    NASA Technical Reports Server (NTRS)

    Brown, Richard F. (Inventor); Edelstein, Fred (Inventor)

    1990-01-01

    A liquid supply control is disclosed for a heat transfer system which transports heat by liquid-vapor phase change of a working fluid. An assembly (10) of monogroove heat pipe legs (15) can be operated automatically as either heat acquisition devices or heat discharge sources. The liquid channels (27) of the heat pipe legs (15) are connected to a reservoir (35) which is filled and drained by respective filling and draining valves (30, 32). Information from liquid level sensors (50, 51) on the reservoir (35) is combined (60) with temperature information (55) from the liquid heat exchanger (12) and temperature information (56) from the assembly vapor conduit (42) to regulate filling and draining of the reservoir (35), so that the reservoir (35) in turn serves the liquid supply/drain needs of the heat pipe legs (15), on demand, by passive capillary action (20, 28).

  5. Analysis of a Flooded Heat Exchanger

    ERIC Educational Resources Information Center

    Fink, Aaron H.; Luyben, William L.

    2015-01-01

    Flooded heat exchangers are often used in industry to reduce the required heat-transfer area and the size of utility control valves. These units involve a condensing vapor on the hot side that accumulates as a liquid phase in the lower part of the vessel. The heat transfer occurs mostly in the vapor space, but the condensate becomes somewhat…

  6. Analysis of a Flooded Heat Exchanger

    ERIC Educational Resources Information Center

    Fink, Aaron H.; Luyben, William L.

    2015-01-01

    Flooded heat exchangers are often used in industry to reduce the required heat-transfer area and the size of utility control valves. These units involve a condensing vapor on the hot side that accumulates as a liquid phase in the lower part of the vessel. The heat transfer occurs mostly in the vapor space, but the condensate becomes somewhat…

  7. Methods for forming wellbores in heated formations

    DOEpatents

    Guimerans, Rosalvina Ramona; Mansure, Arthur James

    2012-09-25

    A method for forming a wellbore in a heated formation includes flowing liquid cooling fluid to a bottom hole assembly in a wellbore in a heated formation. At least a portion of the liquid cooling fluid is vaporized at or near a region to be cooled. Vaporizing the liquid cooling fluid absorbs heat from the region to be cooled.

  8. Premixing and flash vaporization in a two-stage combustor

    SciTech Connect

    Sjoblom, B.G.A.

    1982-01-01

    A double recirculation zone two-stage combustor fitted with airblast atomizers has been investigated in a previous work. This paper describes further tests with premixing tubes in the secondary combustion zone. Flash vaporization was employed to ensure complete vaporization of the secondary fuel, which was heated to 600K by the combustor inlet air. 9 refs.

  9. Coherent 455 nm beam production in a cesium vapor.

    PubMed

    Schultz, J T; Abend, S; Döring, D; Debs, J E; Altin, P A; White, J D; Robins, N P; Close, J D

    2009-08-01

    We observe coherent, cw, 455 nm blue-beam production via frequency upconversion in cesium vapor. Two IR lasers induce strong double excitation in a heated cesium vapor cell, allowing the atoms to undergo a double cascade and produce a coherent, collimated, blue beam copropagating with the two IR pump lasers.

  10. Condensation of acetol and acetic acid vapor with sprayed liquid

    USDA-ARS?s Scientific Manuscript database

    A cellulose-derived fraction of biomass pyrolysis vapor was simulated by evaporating acetol and acetic acid (AA) from flasks on a hot plate. The liquid in the flasks was infused with heated nitrogen. The vapor/nitrogen stream was superheated in a tube oven and condensed by contact with a cloud of ...

  11. Effect of the Thermocouple on Measuring the Temperature Discontinuity at a Liquid-Vapor Interface.

    PubMed

    Kazemi, Mohammad Amin; Nobes, David S; Elliott, Janet A W

    2017-07-18

    The coupled heat and mass transfer that occurs in evaporation is of interest in a large number of fields such as evaporative cooling, distillation, drying, coating, printing, crystallization, welding, atmospheric processes, and pool fires. The temperature jump that occurs at an evaporating interface is of central importance to understanding this complex process. Over the past three decades, thermocouples have been widely used to measure the interfacial temperature jumps at a liquid-vapor interface during evaporation. However, the reliability of these measurements has not been investigated so far. In this study, a numerical simulation of a thermocouple when it measures the interfacial temperatures at a liquid-vapor interface is conducted to understand the possible effects of the thermocouple on the measured temperature and features in the temperature profile. The differential equations of heat transfer in the solid and fluids as well as the momentum transfer in the fluids are coupled together and solved numerically subject to appropriate boundary conditions between the solid and fluids. The results of the numerical simulation showed that while thermocouples can measure the interfacial temperatures in the liquid correctly, they fail to read the actual interfacial temperatures in the vapor. As the results of our numerical study suggest, the temperature jumps at a liquid-vapor interface measured experimentally by using a thermocouple are larger than what really exists at the interface. For a typical experimental study of evaporation of water at low pressure, it was found that the temperature jumps measured by a thermocouple are overestimated by almost 50%. However, the revised temperature jumps are still in agreement with the statistical rate theory of interfacial transport. As well as addressing the specific application of the liquid-vapor temperature jump, this paper provides significant insight into the role that heat transfer plays in the operation of thermocouples

  12. Selective separation of La3+ and lanthanum organic complexes with nanometer-sized titanium dioxide and their detection by using fluorination-assisted electrothermal vaporization ICP-AES with in-situ matrix removal.

    PubMed

    Li, Shengqing; Hu, Bin; Jiang, Zucheng; Liang, Pei; Li, Xuan; Xia, Linbo

    2004-04-01

    A new method for the determination of free La3+ and La organic complexes in solution using a nanometer-sized titanium dioxide as solid-phase extractant and fluorination-assisted electrothermal vaporization (FETV)-ICP-AES as sensitive detector has been developed. The effect of pH on the adsorption characteristics of La3+ and La complexes of citric acid, 2-hydroxyisobutyric acid (HIBA), and humic acid on nanometer-sized TiO2 was investigated and optimized. On the basis of the difference in volatility between fluoride of analyte (lanthanum) and the fluoride of matrix (titanium), an in-situ removal of the adsorbent matrix (TiO2) from a graphite furnace was realized. Therefore, the free La3+ and adsorbed La complexes on nanometer-sized titanium dioxide could be determined respectively by FETV-ICP-AES without any other chemical pretreatment. The proposed method was applied for the determination of free ion (La3+) and La complexes in synthetic solutions and soil extracts with satisfactory results.

  13. Thermodynamic properties of the rare earth element vapor complexes LnAl{sub 3}Cl{sub 12} from Ln = La to Ln = Lu

    SciTech Connect

    Zhi-Chang Wang; Lin-Shan Wang

    1997-04-09

    The rare earth element complexes have never been analyzed in the gaseous state due to experimental concerns. The thermodynamic properties of rare earth element complexes are important for various applications, from high-intensity discharge lamps to recovery of rare earth metals. 46 refs., 4 figs., 1 tab.

  14. Vaporization of droplets in premixing chambers

    NASA Technical Reports Server (NTRS)

    Yule, A. J.; Chigier, N. A.

    1980-01-01

    Detailed measurements were made of the structures of turbulent fuel sprays vaporizing in heated airstreams. The measurements show the size dependent vaporization and dispersion of the droplets and the important influence of the large eddies in the turbulence. The measurements form a data base for the development of models of fuel spray vaporization. Two laser techniques were specially developed for the investigation. A laser tomography technique converts line-of-sight light scattering measurements into time averaged 'point' measurements of droplet size distribution and volume concentration. A laser anemometer particle sizing technique was further developed to permit accurate measurements of individual particle sizes and velocities, with backscatter collection of light. The experiments are combined with heat transfer models to analyze the performance of miniature thermocouples in liquid sprays.

  15. Vapor concentration measurement with photothermal deflectometry

    NASA Technical Reports Server (NTRS)

    Banish, R. Michael; Xiao, Rong-Fu; Rosenberger, Franz

    1988-01-01

    Theoretical and experimental results for using the photothermal deflection technique to measure vapor species concentration, while minimizing the disturbance of the transport (material) parameters due to vapor heating, are developed and described. In contrast to common practice, the above constraints require using a pump-beam duty cycle of less than 50 percent. The theoretical description of the shortened heating time is based on a step-function formulation of the pumping cycle. The results are obtained as closed-form solutions of the energy equation for many chopping cycles until steady state is reached, by use of a Green's-function method. The Euler formulation of the Fermat principle is used to calculate the deflection angle. The equations are expanded to include the effects of vapor velocity on both the temperature and temperature gradient profiles. The effects of finite (unfocused) pump and probe beams and thermal (Soret) diffusion are also accounted for. Excellent agreement between theory and experiment is obtained.

  16. Complex of lithium and tungsten limiters for 3 MW of ECR plasma heating in T-10 tokamak. Design, first results

    NASA Astrophysics Data System (ADS)

    Lyublinski, I. E.; Vertkov, A. V.; Zharkov, M. Yu.; Mirnov, S. V.; Vershkov, V. A.; Glazyuk, Ya. V.; Notkin, G. E.; Grashin, S. A.; Kislov, A. Ya.; Komov, A. T.

    2017-06-01

    A complex of tungsten and lithium limiters is developed. It is expected that application of W as a plasma facing material will allow excluding carbon influx into the vacuum chamber. An additional Li limiter, arranged in the shadow of the W one, will be used as a Li source. The parameters and design of limiters are presented. The plasma facing surface of the Li limiter is constructed to make use of a capillary-porous system (CPS). The porous matrix of the CPS provides stability of liquid Li surface under magnetohydrodinamic force effects, and facilitates its constant renewal due to capillary forces. It is shown that the upgrade of limiters in tokamak Т-10 will allow the provision of electron cyclotron resonance (ECR) plasma heating with power up to 3 MW at reasonable Li flux. The first results on Li-W experiments with ECR heating are presented and discussed. Li limiter design and limiter arrangement configuration for a steady state operating tokamak with a closed cycle of lithium circulation are considered.

  17. Effect of cooling-heating rate on sol-gel transformation of fish gelatin-gum arabic complex coacervate phase.

    PubMed

    Anvari, Mohammad; Chung, Donghwa

    2016-10-01

    The objective of this study was to characterize influence of different cooling and heating rates on gelation of fish gelatin (FG)-gum arabic (GA) complex coacervate phase using rheological measurements. For the coacervate phase prepared at 10°C, the gelling temperature, melting temperature, gel strength, and stress relaxation decreased with increasing cooling or heating rate, however, no gelation was observed at the highest cooling rate of 0.05°C/min. Similar trends were obtained for the coacervates phase prepared at 30°C, but the gelation did not occur at a cooling rate of 0.033 or 0.05°C/min. The results indicated that rheological properties of FG-GA coacervate gels were highly dependent to the cooling process, where more thermos-stable and stronger gels formed at slower cooling. This was probably because of higher degree of molecular rearrangements, more hydrogen bindings, and formation of greater junction zones into the gel network at slower cooling rates. However, all of the FG-GA coacervate gels obtained at different cooling rates were classified as a weak physical gel. Copyright © 2016 Elsevier B.V. All rights reserved.

  18. Stable nanoparticles prepared by heating electrostatic complexes of whey protein isolate-dextran conjugate and chondroitin sulfate.

    PubMed

    Dai, Qingyuan; Zhu, Xiuling; Abbas, Shabbar; Karangwa, Eric; Zhang, Xiaoming; Xia, Shuqin; Feng, Biao; Jia, Chengsheng

    2015-04-29

    A simple and green method was developed for preparing the stable biopolymer nanoparticles with pH and salt resistance. The method involved the macromolecular crowding Maillard process and heat-induced gelation process. The conjugates of whey protein isolate (WPI) and dextran were produced by Maillard reaction. The nanoparticles were fabricated by heating electrostatic complexes of WPI-dextran conjugate and chondroitin sulfate (ChS) above the denaturation temperature and near the isoelectric point of WPI. Then, the nanoparticles were characterized by spectrophotometry, dynamic laser scattering, zeta potential, transmission electron microscopy, atomic force microscopy, and scanning electron microscopy. Results showed that the nanoparticles were stable in the pH range from 1.0 to 8.0 and in the presence of high salt concentration of 200 mM NaCl. WPI-dextran conjugate, WPI, and ChS were assembled into the nanoparticles with dextran conjugated to WPI/ChS shell and WPI/ChS core. The repulsive steric interactions, from both dextran covalently conjugated to WPI and ChS electrostatically interacted with WPI, were the major formation mechanism of the stable nanoparticles. As a nutrient model, lutein could be effectively encapsulated into the nanoparticles. Additionally, the nanoparticles exhibited a spherical shape and homogeneous size distribution regardless of lutein loading. The results suggested that the stable nanoparticles from proteins and strong polyelectrolyte polysaccharides would be used as a promising target delivery system for hydrophobic nutrients and drugs at physiological pH and salt conditions.

  19. Complementary system vaporizes subcooled liquid, improves transformer efficiency

    NASA Technical Reports Server (NTRS)

    Ketaily, E. C.

    1966-01-01

    Complementary system converts subcooled liquid hydrogen or nitrogen to gas. The inherent induction heat losses of an electrical transformer are used in the vaporizing process. Transformer efficiency is improved in the process.

  20. Complex use of waste in wastewater and circulating water treatment from oil in heat power stations

    NASA Astrophysics Data System (ADS)

    Nikolaeva, L. A.; Iskhakova, R. Ya.

    2017-06-01

    Sewage and circulating water from oil of thermal power plants (TPP) generated in fuel-oil shops during washing of electrical equipment and its running into the storm drainage system from the industrial site has been considered in the paper. It has been suggested to use the carbonate sludge of water treatment modified with hydrophobing emulsion as a sorption material for waste and circulating water treatment in thermal power plants. The carbonate sludge is waste accumulated in clarifiers at the stage of natural water pretreatment. General technical characteristics of the sludge, such as moisture, bulk density, total pore volume, ash, etc., have been determined. It has been found that the sludge without additional treatment is a hydrophilic material that has low adsorption capacity and wettability with nonpolar compounds. Therefore, the sludge is treated with organosilicon compounds to reduce the moisture capacity and increase its floatation. Several types of sorption materials based on the carbonate sludge subjected to surface and volume hydrophobization have been developed. During the volume treatment, the hydrophobing compound has been introduced into the material along with the plastifier. In case of the surface treatment, heat-treated granules have been soaked into hydrophobing emulsion. It has been shown that surface hydrophobization is most economically advantageous, because it reduces the consumption of water-repelling agent, wherein the total pore volume and sorption capacity during surface hydrophobization increase by 45 and 25% compared to that during volume hydrophobization. Based on the obtained results, the most effective sorption material has been chosen. To produce this material, it is necessary to sequentially carry out mixing of carbonate sludge with the binder, granulation, calcination, impregnation with a waterrepellent emulsion, and drying of the finished material. The suggested technology to produce the material and use it as a sorbent allows